Dynamic calibration of pan-tilt-zoom cameras for traffic monitoring.

PubMed

Song, Kai-Tai; Tai, Jen-Chao

2006-10-01

Pan-tilt-zoom (PTZ) cameras have been widely used in recent years for monitoring and surveillance applications. These cameras provide flexible view selection as well as a wider observation range. This makes them suitable for vision-based traffic monitoring and enforcement systems. To employ PTZ cameras for image measurement applications, one first needs to calibrate the camera to obtain meaningful results. For instance, the accuracy of estimating vehicle speed depends on the accuracy of camera calibration and that of vehicle tracking results. This paper presents a novel calibration method for a PTZ camera overlooking a traffic scene. The proposed approach requires no manual operation to select the positions of special features. It automatically uses a set of parallel lane markings and the lane width to compute the camera parameters, namely, focal length, tilt angle, and pan angle. Image processing procedures have been developed for automatically finding parallel lane markings. Interesting experimental results are presented to validate the robustness and accuracy of the proposed method.

Reverse design of a bull's eye structure for oblique incidence and wider angular transmission efficiency.

PubMed

Yamada, Akira; Terakawa, Mitsuhiro

2015-04-10

We present a design method of a bull's eye structure with asymmetric grooves for focusing oblique incident light. The design method is capable of designing transmission peaks to a desired oblique angle with capability of collecting light from a wider range of angles. The bull's eye groove geometry for oblique incidence is designed based on the electric field intensity pattern around an isolated subwavelength aperture on a thin gold film at oblique incidence, calculated by the finite difference time domain method. Wide angular transmission efficiency is successfully achieved by overlapping two different bull's eye groove patterns designed with different peak angles. Our novel design method would overcome the angular limitations of the conventional methods.

Catadioptric planar compound eye with large field of view.

PubMed

Deng, Huaxia; Gao, Xicheng; Ma, Mengchao; Li, Yunyang; Li, Hang; Zhang, Jin; Zhong, Xiang

2018-05-14

The planar compound eye has the advantages of simple structure and no requirement for complex relay optical elements, but the field of view (FOV) is very difficult to expand. Overcoming the limitation of FOV, especially with simple structures, is a great challenge for the development of planar compound eyes. Different from the existing designs that only considering refraction, this article proposes a catadioptric planar compound eye based on the reflection and refraction to expand the FOV. In the proposed design, the incident light from a large angle is reflected into the lenslet array by two rotationally symmetric mirrors whose surface equations are optimized by mathematical and optical softwares. The FOV of the proposed catadioptric planar compound eye theoretically can reach 96.6°, which is much wider than the opening record of 70°. Moreover, no distortion of the imaging system can be obtained theoretically in this design. Simulation results show a linearity of better than 99% for the most of the incident angles. The verification experiments show that the FOV of the proposed device can reach 90.7° while the FOV of the corresponding planar compound eye without mirrors is 41.6°. The proposed catadioptric planar compound eye has the great potential in monitoring, detection and virtual reality since the FOV has been widen significantly.

View angle effect in LANDSAT imagery

NASA Technical Reports Server (NTRS)

Kaneko, T.; Engvall, J. L.

1977-01-01

The view angle effect in LANDSAT 2 imagery was investigated. The LANDSAT multispectral scanner scans over a range of view angles of -5.78 to 5.78 degrees. The view angle effect, which is caused by differing view angles, could be studied by comparing data collected at different view angles over a fixed location at a fixed time. Since such LANDSAT data is not available, consecutive day acquisition data were used as a substitute: they were collected over the same geographical location, acquired 24 hours apart, with a view angle change of 7 to 8 degrees at a latitude of 35 to 45 degrees. It is shown that there is approximately a 5% reduction in the average sensor response on the second-day acquisitions as compared with the first-day acquisitions, and that the view angle effect differs field to field and crop to crop. On false infrared color pictures the view angle effect causes changes primarily in brightness and to a lesser degree in color (hue and saturation). An implication is that caution must be taken when images with different view angles are combined for classification and a signature extension technique needs to take the view angle effect into account.

Sun-view angle effects on reflectance factors of corn canopies

NASA Technical Reports Server (NTRS)

Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.; Bauer, M. E.

1985-01-01

The effects of sun and view angles on reflectance factors of corn (Zea mays L.) canopies ranging from the six leaf stage to harvest maturity were studied on the Purdue University Agronomy Farm by a multiband radiometer. The two methods of acquiring spectral data, the truck system and the tower systrem, are described. The analysis of the spectral data is presented in three parts: solar angle effects on reflectance factors viewed at nadir; solar angle effects on reflectance factors viewed at a fixed sun angle; and both sun and view angles effect on reflectance factors. The analysis revealed that for nadir-viewed reflectance factors there is a strong solar angle dependence in all spectral bands for canopies with low leaf area index. Reflectance factors observed from the sun angle at different view azimuth angles showed that the position of the sensor relative to the sun is important in determining angular reflectance characteristics. For both sun and view angles, reflectance factors are maximized when the sensor view direction is towards the sun.

Spheres of Earth: An Introduction to Making Observations of Earth Using an Earth System's Science Approach. Student Guide

NASA Technical Reports Server (NTRS)

Graff, Paige Valderrama; Baker, Marshalyn (Editor); Graff, Trevor (Editor); Lindgren, Charlie (Editor); Mailhot, Michele (Editor); McCollum, Tim (Editor); Runco, Susan (Editor); Stefanov, William (Editor); Willis, Kim (Editor)

2010-01-01

Scientists from the Image Science and Analysis Laboratory (ISAL) at NASA's Johnson Space Center (JSC) work with astronauts onboard the International Space Station (ISS) who take images of Earth. Astronaut photographs, sometimes referred to as Crew Earth Observations, are taken using hand-held digital cameras onboard the ISS. These digital images allow scientists to study our Earth from the unique perspective of space. Astronauts have taken images of Earth since the 1960s. There is a database of over 900,000 astronaut photographs available at http://eol.jsc.nasa.gov . Images are requested by ISAL scientists at JSC and astronauts in space personally frame and acquire them from the Destiny Laboratory or other windows in the ISS. By having astronauts take images, they can specifically frame them according to a given request and need. For example, they can choose to use different lenses to vary the amount of area (field of view) an image will cover. Images can be taken at different times of the day which allows different lighting conditions to bring out or highlight certain features. The viewing angle at which an image is acquired can also be varied to show the same area from different perspectives. Pointing the camera straight down gives you a nadir shot. Pointing the camera at an angle to get a view across an area would be considered an oblique shot. Being able to change these variables makes astronaut photographs a unique and useful data set. Astronaut photographs are taken from the ISS from altitudes of 300 - 400 km (185 to 250 miles). One of the current cameras being used, the Nikon D3X digital camera, can take images using a 50, 100, 250, 400 or 800mm lens. These different lenses allow for a wider or narrower field of view. The higher the focal length (800mm for example) the narrower the field of view (less area will be covered). Higher focal lengths also show greater detail of the area on the surface being imaged. Scientists from the Image Science and Analysis Laboratory (ISAL) at NASA s Johnson Space Center (JSC) work with astronauts onboard the International Space Station (ISS) who take images of Earth. Astronaut photographs, sometimes referred to as Crew Earth Observations, are taken using hand-held digital cameras onboard the ISS. These digital images allow scientists to study our Earth from the unique perspective of space. Astronauts have taken images of Earth since the 1960s. There is a database of over 900,000 astronaut photographs available at http://eol.jsc.nasa.gov . Images are requested by ISAL scientists at JSC and astronauts in space personally frame and acquire them from the Destiny Laboratory or other windows in the ISS. By having astronauts take images, they can specifically frame them according to a given request and need. For example, they can choose to use different lenses to vary the amount of area (field of view) an image will cover. Images can be taken at different times of the day which allows different lighting conditions to bring out or highlight certain features. The viewing angle at which an image is acquired can also be varied to show the same area from different perspectives. Pointing the camera straight down gives you a nadir shot. Pointing the camera at an angle to get a view across an area would be considered an oblique shot. Being able to change these variables makes astronaut photographs a unique and useful data set. Astronaut photographs are taken from the ISS from altitudes of 300 - 400 km (approx.185 to 250 miles). One of the current cameras being used, the Nikon D3X digital camera, can take images using a 50, 100, 250, 400 or 800mm lens. These different lenses allow for a wider or narrower field of view. The higher the focal length (800mm for example) the narrower the field of view (less area will be covered). Higher focal lengths also show greater detail of the area on the surface being imaged. There are four major systems or spheres of Earth. They are: Atmosphere, Biosphere, Hydrosphe, and Litho/Geosphere.

Water-tunnel study results of a TF/A-18 and F/A-18 canopy flow visualization

NASA Technical Reports Server (NTRS)

Johnson, Steven A.; Fisher, David F.

1990-01-01

A water tunnel study examining the influence of canopy shape on canopy and leading edge extension flow patterns was initiated. The F/A-18 single-place canopy model and the TF/A-18 two place canopy model were the study subjects. Plan view and side view photographs showing the flow patterns created by injected colored dye are presented for 0 deg and 5 deg sideslip angles. Photographs taken at angle of attack and sideslip conditions correspond to test departure points found in flight test. Flight experience has shown that the TF/A-18 airplane departs in regions where the F/A-18 airplane is departure-resistant. The study results provide insight into the differences in flow patterns which may influence the resulting aerodynamics of the TF/A-18 and F/A-18 aircraft. It was found that at 0 deg sideslip, the TF/A-18 model has more downward flow on the sides of the canopy than the F/A-18 model. This could be indicative of flow from the leading edge extension (LEX) vortexes impinging on the sides of the wider TF/A-18 canopy. In addition, the TF/A-18 model has larger areas of asymmetric separated and unsteady flow on the LEXs and fuselage, possibly indicating a lateral and directional destabilizing effect at the conditions studied.

Preferred viewing distance and screen angle of electronic paper displays.

PubMed

Shieh, Kong-King; Lee, Der-Song

2007-09-01

This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and screen angle were 495 mm and 123.7 degrees. The mean viewing distances for Kolin Chlorestic Liquid Crystal display was 500 mm, significantly longer than Sony electronic ink display, 491 mm. Screen angle for Kolin was 127.4 degrees, significantly greater than that of Sony, 120.0 degrees. Various light sources revealed no significant effect on viewing distances; nevertheless, they showed significant effect on screen angles. The screen angle for sunlight lamp (D65) was similar to that of fluorescent lamp (TL84), but greater than that of tungsten lamp (F). Ambient illumination and E-paper type had significant effects on viewing distance and screen angle. The higher the ambient illumination was, the longer the viewing distance and the lesser the screen angle. Character size had significant effect on viewing distances: the larger the character size, the longer the viewing distance. The results of this study indicated that the viewing distance for E-Paper was similar to that of visual display terminal (VDT) at around 500 mm, but greater than normal paper at about 360 mm. The mean screen angle was around 123.7 degrees, which in terms of viewing angle is 29.5 degrees below horizontal eye level. This result is similar to the general suggested viewing angle between 20 degrees and 50 degrees below the horizontal line of sight.

Morphology and isozyme band-profile as sexual determinant of nutmeg plant (Myristica fragrants Houttj).

NASA Astrophysics Data System (ADS)

Karmanah; Maslahat, M.; Nurhayati, dan L.

2016-01-01

Sex information in nutmeg plant is important to distinguish between male and female species. The recommendation of optimum sex-ratio for a nutmeg plantation is 1:10. This research is aimed to discover the morphological characteristic of nutmeg plant and the difference of leaf pattern as sexual determinant between male and female plant with the comparison of isozyme analysis. The result of morphological identification provided from 3 research farm location indicated that female nutmeg was higher, with longer and wider leaf, more vein, bigger diameter of stem and branching angle as compared to male nutmeg. Two parameters which were widht of leaf and branching angle showed significant differences, where female nutmeg plants have wider leaves and branching angle. Isozyme analysis suggested that the analysis of peroxidase enzyme (PER) was better and able to provide more information than aspartarte amino transferase (AAT) and acid phospatase (ACP) Enzymes.

Retrospective exploration of risk factors for L5 radiculopathy following lumbar floating fusion surgery.

PubMed

Orita, Sumihisa; Yamagata, Masatsune; Ikeda, Yoshikazu; Nakajima, Fumitake; Aoki, Yasuchika; Nakamura, Junichi; Takahashi, Kazuhisa; Suzuki, Takane; Ohtori, Seiji

2015-10-17

Lumbar floating fusion occasionally causes postoperative adjacent segment disorder (ASD) at lumbosacral level, causing L5 spinal nerve disorder by L5-S1 foraminal stenosis. The disorder is considered to be one of the major outcomes of L5-S1 ASD, which has not been evaluated yet. The present study aimed to evaluate the incidence and risk factors of postoperative L5 spinal nerve disorder after lumbar interbody fusion extending to the L5 vertebra. We evaluated 125 patients with a diagnosis of spondylolisthesis who underwent floating fusion surgery with transforaminal lumbar interbody fusion with average postoperative period of 25.2 months. The patients were regarded as symptomatic with postoperative L5 spinal nerve disorder such as radicular pain/numbness in the lower limbs and/or motor dysfunction. We estimated and compared the wedging angle (frontal view) and height (lateral view) of the lumbosacral junction in pre- and postoperative plain X-ray images and the foraminal ratio (ratio of the narrower foraminal diameter to the wider diameter in the craniocaudal direction) in the preoperative magnetic resonance image. Risk factors for the incidence of L5 spinal nerve disorder were explored using multivariate logistic regression. Eight of the 125 patients (6.4%) were categorized as symptomatic, an average of 13.3 months after surgery. The wedging angle was significantly higher, and the foraminal ratio was significantly decreased in the symptomatic group (both P < 0.05) compared to the asymptomatic group. Multivariate logistic regression analysis of possible risk factors revealed that the wedging angle, foraminal ratio, and multileveled fusion were statistically significant. Higher wedging angle and lower foraminal ratio in the lumbosacral junction were significantly predictive for the incidence of L5 nerve root disorder as well as multiple-leveled fusion. These findings indicate that lumbosacral fixation should be considered for patients with these risk factors even if they have few symptoms from the L5-S1 junction.

Bidirectional measurements of surface reflectance for view angle corrections of oblique imagery

NASA Technical Reports Server (NTRS)

Jackson, R. D.; Teillet, P. M.; Slater, P. N.; Fedosejevs, G.; Jasinski, Michael F.

1990-01-01

An apparatus for acquiring bidirectional reflectance-factor data was constructed and used over four surface types. Data sets were obtained over a headed wheat canopy, bare soil having several different roughness conditions, playa (dry lake bed), and gypsum sand. Results are presented in terms of relative bidirectional reflectance factors (BRFs) as a function of view angle at a number of solar zenith angles, nadir BRFs as a function of solar zenith angles, and, for wheat, vegetation indices as related to view and solar zenith angles. The wheat canopy exhibited the largest BRF changes with view angle. BRFs for the red and the NIR bands measured over wheat did not have the same relationship with view angle. NIR/Red ratios calculated from nadir BRFs changed by nearly a factor of 2 when the solar zenith angle changed from 20 to 50 degs. BRF versus view angle relationships were similar for soils having smooth and intermediate rough surfaces but were considerably different for the roughest surface. Nadir BRF versus solar-zenith angle relationships were distinctly different for the three soil roughness levels. Of the various surfaces, BRFs for gypsum sand changed the least with view angle (10 percent at 30 degs).

View-invariant object recognition ability develops after discrimination, not mere exposure, at several viewing angles.

PubMed

Yamashita, Wakayo; Wang, Gang; Tanaka, Keiji

2010-01-01

One usually fails to recognize an unfamiliar object across changes in viewing angle when it has to be discriminated from similar distractor objects. Previous work has demonstrated that after long-term experience in discriminating among a set of objects seen from the same viewing angle, immediate recognition of the objects across 30-60 degrees changes in viewing angle becomes possible. The capability for view-invariant object recognition should develop during the within-viewing-angle discrimination, which includes two kinds of experience: seeing individual views and discriminating among the objects. The aim of the present study was to determine the relative contribution of each factor to the development of view-invariant object recognition capability. Monkeys were first extensively trained in a task that required view-invariant object recognition (Object task) with several sets of objects. The animals were then exposed to a new set of objects over 26 days in one of two preparatory tasks: one in which each object view was seen individually, and a second that required discrimination among the objects at each of four viewing angles. After the preparatory period, we measured the monkeys' ability to recognize the objects across changes in viewing angle, by introducing the object set to the Object task. Results indicated significant view-invariant recognition after the second but not first preparatory task. These results suggest that discrimination of objects from distractors at each of several viewing angles is required for the development of view-invariant recognition of the objects when the distractors are similar to the objects.

Relationships Between Age at Menarche, Walking Gait Base of Support, and Stance Phase Frontal Plane Knee Biomechanics in Adolescent Girls.

PubMed

Froehle, Andrew W; Grannis, Kimberly A; Sherwood, Richard J; Duren, Dana L

2017-05-01

Age at menarche impacts patterns of pubertal growth and skeletal development. These effects may carry over into variation in biomechanical profiles involved in sports-related traumatic and overuse knee injuries. The present study investigated whether age at menarche is a potential indicator of knee injury risk through its influence on knee biomechanics during normal walking. To test the hypothesis that earlier menarche is related to postpubertal biomechanical risk factors for knee injuries, including a wider, more immature gait base of support, and greater valgus knee angles and moments. Cross-sectional observational study. University research facility. Healthy, postmenarcheal, adolescent girls. Age at menarche was obtained by recall questionnaire. Pubertal growth and anthropometric data were collected by using standard methods. Biomechanical data were taken from tests of walking gait at self-selected speed. Reflective marker position data were collected with a 3-dimensional quantitative motion analysis system, and 3 force plates recorded kinetic data. Age at menarche; growth and anthropometric measurements; base of support; static knee frontal plane angle; and dynamic knee frontal plane angles and moments during stance. Earlier menarche was correlated significantly with abbreviated pubertal growth and postpubertal retention of immature traits, including a wider base of support. Earlier menarche and wider base of support were both correlated with more valgus static knee angles, more valgus knee abduction angles and moments at foot-strike, and a more valgus peak knee abduction angle during stance. Peak knee abduction moment during stance was not correlated with age at menarche or base of support. Earlier menarche and its effects on growth are associated with retention of a relatively immature gait base of support and a tendency for static and dynamic valgus knee alignment. This biomechanical profile may put girls with earlier menarche at greater risk for sports-related knee injuries. Not applicable. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Relationships between age at menarche, walking gait base of support, and stance phase frontal plane knee biomechanics in adolescent females

PubMed Central

Grannis, Kimberly A.; Sherwood, Richard J.; Duren, Dana L

2016-01-01

Background Age at menarche impacts patterns of pubertal growth and skeletal development. These effects may carry over into variation in biomechanical profiles involved in sports-related traumatic and overuse knee injuries. The present study investigated whether age at menarche is a potential indicator of knee injury risk through its influence on knee biomechanics during normal walking. Objective To test the hypothesis that earlier menarche is related to post-pubertal biomechanical risk factors for knee injuries, including a wider, more immature gait base of support, and greater valgus knee angles and moments. Design Cross-sectional observational study. Setting University research facility. Participants Healthy, post-menarcheal, adolescent females. Methods Age at menarche was obtained by recall questionnaire. Pubertal growth and anthropometric data were collected using standard methods. Biomechanical data were taken from tests of walking gait at self-selected speed. Reflective marker position data were collected using a three-dimensional quantitative motion analysis system, and three force plates recorded kinetic data. Main Outcome Measures Age at menarche; growth and anthropometric measurements; base of support; static knee frontal plane angle; dynamic knee frontal plane angles and moments during stance. Results Earlier menarche was significantly correlated with abbreviated pubertal growth and post-pubertal retention of immature traits, including a wider base of support. Earlier menarche and wider base of support were both correlated with more valgus static knee angles, more valgus knee abduction angles and moments at foot-strike, and a more valgus peak knee abduction angle during stance. Peak knee abduction moment during stance was not correlated with age at menarche or base of support. Conclusions Earlier menarche and its effects on growth are associated with retention of a relatively immature gait base of support and a tendency for static and dynamic valgus knee alignment. This biomechanical profile may put girls with earlier menarche at higher risk for sports-related knee injuries. PMID:27485675

The Wider Benefits of Further Education: Practitioner Views. Wider Benefits of Learning Research Report.

ERIC Educational Resources Information Center

Preston, John; Hammond, Cathie

The wider benefits of further education (FE) were examined in a survey circulated to more than 10,000 FE practitioners in a representative sample of FE colleges throughout England. A total of 2,729 questionnaires (approximately 27%) were returned. The following were among the benefits of FE cited: esteem; efficacy; independence of thought; problem…

Vastus lateralis single motor unit EMG at the same absolute torque production at different knee angles.

PubMed

Altenburg, T M; de Haan, A; Verdijk, P W L; van Mechelen, W; de Ruiter, C J

2009-07-01

Single motor unit electromyographic (EMG) activity of the knee extensors was investigated at different knee angles with subjects (n = 10) exerting the same absolute submaximal isometric torque at each angle. Measurements were made over a 20 degrees range around the optimum angle for torque production (AngleTmax) and, where feasible, over a wider range (50 degrees ). Forty-six vastus lateralis (VL) motor units were recorded at 20.7 +/- 17.9 %maximum voluntary contraction (%MVC) together with the rectified surface EMG (rsEMG) of the superficial VL muscle. Due to the lower maximal torque capacity at positions more flexed and extended than AngleTmax, single motor unit recruitment thresholds were expected to decrease and discharge rates were expected to increase at angles above and below AngleTmax. Unexpectedly, the recruitment threshold was higher (P < 0.05) at knee angles 10 degrees more extended (43.7 +/- 22.2 N.m) and not different (P > 0.05) at knee angles 10 degrees more flexed (35.2 +/- 17.9 N.m) compared with recruitment threshold at AngleTmax (41.8 +/- 21.4 N.m). Also, unexpectedly the discharge rates were similar (P > 0.05) at the three angles: 11.6 +/- 2.2, 11.6 +/- 2.1, and 12.3 +/- 2.1 Hz. Similar angle independent discharge rates were also found for 12 units (n = 5; 7.4 +/- 5.4 %MVC) studied over the wider (50 degrees ) range, while recruitment threshold only decreased at more flexed angles. In conclusion, the similar recruitment threshold and discharge behavior of VL motor units during submaximal isometric torque production suggests that net motor unit activation did not change very much along the ascending limb of the knee-angle torque relationship. Several factors such as length-dependent twitch potentiation, which may contribute to this unexpected aspect of motor control, are discussed.

Omni-Directional Viewing-Angle Switching through Control of the Beam Divergence Angle in a Liquid Crystal Panel

NASA Astrophysics Data System (ADS)

Baek, Jong-In; Kim, Ki-Han; Kim, Jae Chang; Yoon, Tae-Hoon

2010-01-01

This paper proposes a method of omni-directional viewing-angle switching by controlling the beam diverging angle (BDA) in a liquid crystal (LC) panel. The LCs aligned randomly by in-cell polymer structures diffuse the collimated backlight for the bright state of the wide viewing-angle mode. We align the LCs homogeneously by applying an in-plane field for the narrow viewing-angle mode. By doing this the scattering is significantly reduced so that the small BDA is maintained as it passes through the LC layer. The dark state can be obtained by aligning the LCs homeotropically with a vertical electric field. We demonstrated experimentally the omni-directional switching of the viewing-angle, without an additional panel or backlighting system.

Endoscopy in neuro-otologic surgery.

PubMed

Wackym, Phillip A; King, Wesley A; Meyer, Glenn A; Poe, Dennis S

2002-04-01

Endoscopy offers several distinct advantages over the operating microscope during neuro-otologic surgery that make it an excellent adjunctive tool to the microscope or independent modality during cranial base surgery. The high magnification gives excellent definition of perforating blood vessels, cranial nerves, and neural structures, which in many cases is superior to that achieved with the microscope. Furthermore, the use of angled or flexible endoscopes allows one to look around corners and behind anatomic structures blocking the view seen via a 0 degree microscope. Endoscopy also has the theoretical advantage that a less invasive operative procedure is required, which should reduce the operative morbidity. Several notable disadvantages of endoscopy include the problems associated with blood soiling the endoscope, making visualization difficult or impossible, the lack of readily available instrumentation designed specifically for endoscopic neuro-otology, and the poor overview of the operative field. This last point is an important one because the endoscope is placed adjacent to the lesion and does not allow one to look backward to prevent [figure: see text] injury to structures next to the shaft of the telescope. Furthermore, the surgeon must be cognizant of potential thermal injury to structures caused by the heat generated by the light source. The present endoscopic technology limits the image that the surgeon sees to two dimensions, which results in certain unique problems when operating in a three-dimensional milieu. Because of this, there is a steep learning curve to acquire endoscopic dexterity and three-dimensional orientation. Finally, bimanual operation requires the use of an articulated endoscope holder or the commitment of the co-surgeon to hold the endoscope. One of the limitations of the operative microscope is that the angle of view is determined by the distance of the lens to the skull, retractor, or obstructing tissue, which is a function of the lens focal length; the longer the focal length, the narrower the viewing angle. During most microsurgical procedures, the focal distance varies between 200 and 400 mm. Using a previous analogy, if one looks through a door's keyhole at close range, nearly the entire room on the opposite side of the door can be seen, although nothing can be seen when the hole is viewed from a long distance. This is similar to what happens when using the endoscope with focal lengths ranging from 5 to 20 mm: a wider angle of view can be achieved. Based on their, experience the authors believe that endoscopes can be used safely during neuro-otologic surgery. As an adjunct to or substitution for the operative microscope, this modality does improve visualization of bony, neural, and vascular structures while minimizing cerebellar retraction.

Compensation method for the influence of angle of view on animal temperature measurement using thermal imaging camera combined with depth image.

PubMed

Jiao, Leizi; Dong, Daming; Zhao, Xiande; Han, Pengcheng

2016-12-01

In the study, we proposed an animal surface temperature measurement method based on Kinect sensor and infrared thermal imager to facilitate the screening of animals with febrile diseases. Due to random motion and small surface temperature variation of animals, the influence of the angle of view on temperature measurement is significant. The method proposed in the present study could compensate the temperature measurement error caused by the angle of view. Firstly, we analyzed the relationship between measured temperature and angle of view and established the mathematical model for compensating the influence of the angle of view with the correlation coefficient above 0.99. Secondly, the fusion method of depth and infrared thermal images was established for synchronous image capture with Kinect sensor and infrared thermal imager and the angle of view of each pixel was calculated. According to experimental results, without compensation treatment, the temperature image measured in the angle of view of 74° to 76° showed the difference of more than 2°C compared with that measured in the angle of view of 0°. However, after compensation treatment, the temperature difference range was only 0.03-1.2°C. This method is applicable for real-time compensation of errors caused by the angle of view during the temperature measurement process with the infrared thermal imager. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gaze and viewing angle influence visual stabilization of upright posture

PubMed Central

Ustinova, KI; Perkins, J

2011-01-01

Focusing gaze on a target helps stabilize upright posture. We investigated how this visual stabilization can be affected by observing a target presented under different gaze and viewing angles. In a series of 10-second trials, participants (N = 20, 29.3 ± 9 years of age) stood on a force plate and fixed their gaze on a figure presented on a screen at a distance of 1 m. The figure changed position (gaze angle: eye level (0°), 25° up or down), vertical body orientation (viewing angle: at eye level but rotated 25° as if leaning toward or away from the participant), or both (gaze and viewing angle: 25° up or down with the rotation equivalent of a natural visual perspective). Amplitude of participants’ sagittal displacement, surface area, and angular position of the center of gravity (COG) were compared. Results showed decreased COG velocity and amplitude for up and down gaze angles. Changes in viewing angles resulted in altered body alignment and increased amplitude of COG displacement. No significant changes in postural stability were observed when both gaze and viewing angles were altered. Results suggest that both the gaze angle and viewing perspective may be essential variables of the visuomotor system modulating postural responses. PMID:22398978

Dual-mode switching of a liquid crystal panel for viewing angle control

NASA Astrophysics Data System (ADS)

Baek, Jong-In; Kwon, Yong-Hoan; Kim, Jae Chang; Yoon, Tae-Hoon

2007-03-01

The authors propose a method to control the viewing angle of a liquid crystal (LC) panel using dual-mode switching. To realize both wide viewing angle (WVA) characteristics and narrow viewing angle (NVA) characteristics with a single LC panel, the authors use two different dark states. The LC layer can be aligned homogeneously parallel to the transmission axis of the bottom polarizer for WVA dark state operation, while it can be aligned vertically for NVA dark state operation. The authors demonstrated that viewing angle control can be achieved with a single panel without any loss of contrast at the front.

The Influence of the Project Method on the Achievement of Young Learners in the Field Science and Social Studies

ERIC Educational Resources Information Center

Prtljaga, Snežana; Veselinov, Danica

2017-01-01

The paper deals with the influence of project work on the achievement of young learners in the area of science and social studies. The presented results are part of a wider study, in which they were interpreted from a different angle. The goal of the wider study was to determine to what extent a higher level of knowledge acquisition in the field…

Relationship between iris surface features and angle width in Asian eyes.

PubMed

Sidhartha, Elizabeth; Nongpiur, Monisha Esther; Cheung, Carol Y; He, Mingguang; Wong, Tien Yin; Aung, Tin; Cheng, Ching-Yu

2014-10-23

To examine the associations between iris surface features with anterior chamber angle width in Asian eyes. In this prospective cross-sectional study, we recruited 600 subjects from a large population-based study, the Singapore Epidemiology of Eye Diseases (SEED) study. We obtained standardized digital slit-lamp iris photographs and graded the iris crypts (by number and size), furrows (by number and circumferential extent), and color (higher grade denoting darker iris). Vertical and horizontal cross-sections of anterior chamber were imaged using anterior segment optical coherence tomography. Angle opening distance (AOD), angle recess area (ARA), and trabecular-iris space area (TISA) were measured using customized software. Associations of the angle width with the iris surface features in the subject's right eyes were assessed using linear regression analysis. A total of 464 eyes of the 464 subjects (mean age: 57.5 ± 8.6 years) had complete and gradable data for crypts and color, and 423 eyes had gradable data for furrows. After adjustment for age, sex, ethnicity, pupil size, and corneal arcus, higher crypt grade was independently associated with wider AOD750 (β [change in angle width per grade higher] = 0.018, P = 0.023), ARA750 (β = 0.022, P = 0.049), and TISA750 (β = 0.011, P = 0.019), and darker iris was associated narrower ARA750 (β = -0.025, P = 0.044) and TISA750 (β = -0.013, P = 0.011). Iris surface features, assessed and measured from slit-lamp photographs, correlated well with anterior chamber angle width; irises with more crypts and lighter color were associated with wider angle. These findings may provide another imaging modality to assess angle closure risk based on iris surface features. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Neural Substrates of View-Invariant Object Recognition Developed without Experiencing Rotations of the Objects

PubMed Central

Okamura, Jun-ya; Yamaguchi, Reona; Honda, Kazunari; Tanaka, Keiji

2014-01-01

One fails to recognize an unfamiliar object across changes in viewing angle when it must be discriminated from similar distractor objects. View-invariant recognition gradually develops as the viewer repeatedly sees the objects in rotation. It is assumed that different views of each object are associated with one another while their successive appearance is experienced in rotation. However, natural experience of objects also contains ample opportunities to discriminate among objects at each of the multiple viewing angles. Our previous behavioral experiments showed that after experiencing a new set of object stimuli during a task that required only discrimination at each of four viewing angles at 30° intervals, monkeys could recognize the objects across changes in viewing angle up to 60°. By recording activities of neurons from the inferotemporal cortex after various types of preparatory experience, we here found a possible neural substrate for the monkeys' performance. For object sets that the monkeys had experienced during the task that required only discrimination at each of four viewing angles, many inferotemporal neurons showed object selectivity covering multiple views. The degree of view generalization found for these object sets was similar to that found for stimulus sets with which the monkeys had been trained to conduct view-invariant recognition. These results suggest that the experience of discriminating new objects in each of several viewing angles develops the partially view-generalized object selectivity distributed over many neurons in the inferotemporal cortex, which in turn bases the monkeys' emergent capability to discriminate the objects across changes in viewing angle. PMID:25378169

Polarimetric Imaging for the Detection of Disturbed Surfaces

DTIC Science & Technology

2009-06-01

9 Figure 4. Rayleigh Roughness Criterion as a Function of Incident Angle ......................10 Figure 5. Definition of Geometrical...Terms (after Egan & Hallock, 1966).....................11 Figure 6. Haleakala Ash Depolarization for (a) °0 Viewing Angle and (b) °60 Viewing... Angle (from Egan et al., 1968)..........................................................13 Figure 7. Basalt Depolarization at (a) °0 Viewing Angle and

Numerical investigation on the viewing angle of a lenticular three-dimensional display with a triplet lens array.

PubMed

Kim, Hwi; Hahn, Joonku; Choi, Hee-Jin

2011-04-10

We investigate the viewing angle enhancement of a lenticular three-dimensional (3D) display with a triplet lens array. The theoretical limitations of the viewing angle and view number of the lenticular 3D display with the triplet lens array are analyzed numerically. For this, the genetic-algorithm-based design method of the triplet lens is developed. We show that a lenticular 3D display with viewing angle of 120° and 144 views without interview cross talk can be realized with the use of an optimally designed triplet lens array. © 2011 Optical Society of America

Neural substrates of view-invariant object recognition developed without experiencing rotations of the objects.

PubMed

Okamura, Jun-Ya; Yamaguchi, Reona; Honda, Kazunari; Wang, Gang; Tanaka, Keiji

2014-11-05

One fails to recognize an unfamiliar object across changes in viewing angle when it must be discriminated from similar distractor objects. View-invariant recognition gradually develops as the viewer repeatedly sees the objects in rotation. It is assumed that different views of each object are associated with one another while their successive appearance is experienced in rotation. However, natural experience of objects also contains ample opportunities to discriminate among objects at each of the multiple viewing angles. Our previous behavioral experiments showed that after experiencing a new set of object stimuli during a task that required only discrimination at each of four viewing angles at 30° intervals, monkeys could recognize the objects across changes in viewing angle up to 60°. By recording activities of neurons from the inferotemporal cortex after various types of preparatory experience, we here found a possible neural substrate for the monkeys' performance. For object sets that the monkeys had experienced during the task that required only discrimination at each of four viewing angles, many inferotemporal neurons showed object selectivity covering multiple views. The degree of view generalization found for these object sets was similar to that found for stimulus sets with which the monkeys had been trained to conduct view-invariant recognition. These results suggest that the experience of discriminating new objects in each of several viewing angles develops the partially view-generalized object selectivity distributed over many neurons in the inferotemporal cortex, which in turn bases the monkeys' emergent capability to discriminate the objects across changes in viewing angle. Copyright © 2014 the authors 0270-6474/14/3415047-13$15.00/0.

Directional infrared temperature and emissivity of vegetation: Measurements and models

NASA Technical Reports Server (NTRS)

Norman, J. M.; Castello, S.; Balick, L. K.

1994-01-01

Directional thermal radiance from vegetation depends on many factors, including the architecture of the plant canopy, thermal irradiance, emissivity of the foliage and soil, view angle, slope, and the kinetic temperature distribution within the vegetation-soil system. A one dimensional model, which includes the influence of topography, indicates that thermal emissivity of vegetation canopies may remain constant with view angle, or emissivity may increase or decrease as view angle from nadir increases. Typically, variations of emissivity with view angle are less than 0.01. As view angle increases away from nadir, directional infrared canopy temperature usually decreases but may remain nearly constant or even increase. Variations in directional temperature with view angle may be 5C or more. Model predictions of directional emissivity are compared with field measurements in corn canopies and over a bare soil using a method that requires two infrared thermometers, one sensitive to the 8 to 14 micrometer wavelength band and a second to the 14 to 22 micrometer band. After correction for CO2 absorption by the atmosphere, a directional canopy emissivity can be obtained as a function of view angle in the 8 to 14 micrometer band to an accuracy of about 0.005. Modeled and measured canopy emissivities for corn varied slightly with view angle (0.990 at nadir and 0.982 at 75 deg view zenith angle) and did not appear to vary significantly with view angle for the bare soil. Canopy emissivity is generally nearer to unity than leaf emissivity may vary by 0.02 with wavelength even though leaf emissivity. High spectral resolution, canopy thermal emissivity may vary by 0.02 with wavelength even though leaf emissivity may vary by 0.07. The one dimensional model provides reasonably accurate predictions of infrared temperature and can be used to study the dependence of infrared temperature on various plant, soil, and environmental factors.

A new species of freshwater crab of the genus Oziotelphusa Müller, 1887 (Crustacea: Decapoda: Brachyura: Gecarcinucidae) from Tamil Nadu, southern India.

PubMed

Raj, Smrithy; Kumar, Appukuttannair Biju; Ng, Peter K L

2017-12-10

A new species of gecarcinucid freshwater crab of the genus Oziotelphusa Müller, 1887, is described from stationary or slow-flowing bodies of water in Keeriparai near Nagercoil, in the state of Tamil Nadu in southern India. Oziotelphusa ravi, new species, is distinguished from its congeners by several distinct characters: the median tooth of the posterior margin of epistome forms a distinct bilobed tip in frontal view, the male pleonal somite 6 is narrowly trapezoidal and slightly wider than long with the lateral margins concave, the terminal segment of the male first gonopod is distinctly bent laterally (along the longitudinal axis) at an angle of about 45°, and the proximal part of the outer margin of the subterminal segment of the male first gonopod has a prominent deep concavity.

Enhanced light output from a nitride-based power chip of green light-emitting diodes with nano-rough surface using nanoimprint lithography.

PubMed

Huang, H W; Lin, C H; Yu, C C; Lee, B D; Chiu, C H; Lai, C F; Kuo, H C; Leung, K M; Lu, T C; Wang, S C

2008-05-07

Enhanced light extraction from a GaN-based power chip (PC) of green light-emitting diodes (LEDs) with a rough p-GaN surface using nanoimprint lithography is presented. At a driving current of 350 mA and with a chip size of 1 mm × 1 mm packaged on transistor outline (TO)-cans, the light output power of the green PC LEDs with nano-rough p-GaN surface is enhanced by 48% when compared with the same device without a rough p-GaN surface. In addition, by examining the radiation patterns, the green PC LED with nano-rough p-GaN surface shows stronger light extraction with a wider view angle. These results offer promising potential to enhance the light output powers of commercial light-emitting devices by using the technique of nanoimprint lithography under suitable nanopattern design.

Widening of the femoral proximal diaphysis--metaphysis angle in fetuses with achondroplasia.

PubMed

Khalil, A; Morales-Roselló, J; Morlando, M; Bhide, A; Papageorghiou, A; Thilaganathan, B

2014-07-01

It has recently been reported that fetuses with achondroplasia have a wider than expected femoral proximal diaphysis-metaphysis angle (femoral angle). The aim of this case-control study was to investigate this finding. Cases with confirmed achondroplasia (n = 6), small-for-gestational-age fetuses (n = 70) and a group of normal fetuses (n = 377) were included in this study. The ultrasound image of the femur was examined by two independent experienced observers blinded to the diagnosis, who measured the femoral angle. These values were converted into multiples of the expected median (MoM), after adjustment for gestational age and femur length. Prevalence of various prenatal ultrasound signs of achondroplasia was determined in affected fetuses. Intra- and interobserver agreement of measurement of femoral angle was assessed using 95% limits of agreement and kappa statistics. The femoral angle can be measured accurately by ultrasound, and increases with both increasing gestational age and increasing femur length. The femoral angle-MoM was significantly higher in fetuses with achondroplasia than in the control group (1.36 vs 1.00 MoM, P < 0.001) and in the SGA group (1.36 vs 1.04 MoM, P < 0.001). It measured more than 130° in five of the six cases with achondroplasia (83.3%), which was the most consistent finding other than shortening of the long bones. The femoral angle is wider in fetuses with achondroplasia. This new ultrasound sign appears promising as an additional discriminatory marker when clinicians are faced with a case of short long bones in the third trimester. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Polarimetric Thermal Imaging

DTIC Science & Technology

2007-03-01

front of a large area blackbody as background. The viewing angle , defined as the angle between surface normal and camera line of sight, was varied by...and polarization angle were derived from the Stokes parameters. The dependence of these polarization characteristics on viewing angle was investigated

29. View of paired concreteencased columns at joint between beams ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. View of paired concrete-encased columns at joint between beams contrasted against wider single columns. Looking east. - Stillwell Avenue Station, Intersection of Stillwell & Surf Avenues, Brooklyn, Kings County, NY

Assistive peripheral phosphene arrays deliver advantages in obstacle avoidance in simulated end-stage retinitis pigmentosa: a virtual-reality study

NASA Astrophysics Data System (ADS)

Zapf, Marc Patrick H.; Boon, Mei-Ying; Lovell, Nigel H.; Suaning, Gregg J.

2016-04-01

Objective. The prospective efficacy of peripheral retinal prostheses for guiding orientation and mobility in the absence of residual vision, as compared to an implant for the central visual field (VF), was evaluated using simulated prosthetic vision (SPV). Approach. Sighted volunteers wearing a head-mounted display performed an obstacle circumvention task under SPV. Mobility and orientation performance with three layouts of prosthetic vision were compared: peripheral prosthetic vision of higher visual acuity (VA) but limited VF, of wider VF but limited VA, as well as centrally restricted prosthetic vision. Learning curves using these layouts were compared fitting an exponential model to the mobility and orientation measures. Main results. Using peripheral layouts, performance was superior to the central layout. Walking speed with both higher-acuity and wider-angle layouts was 5.6% higher, and mobility errors reduced by 46.4% and 48.6%, respectively, as compared to the central layout. The wider-angle layout yielded the least number of collisions, 63% less than the higher-acuity and 73% less than the central layout. Using peripheral layouts, the number of visual-scanning related head movements was 54.3% (higher-acuity) and 60.7% (wider-angle) lower, as compared to the central layout, and the ratio of time standing versus time walking was 51.9% and 61.5% lower, respectively. Learning curves did not differ between layouts, except for time standing versus time walking, where both peripheral layouts achieved significantly lower asymptotic values compared to the central layout. Significance. Beyond complementing residual vision for an improved performance, peripheral prosthetic vision can effectively guide mobility in the later stages of retinitis pigmentosa (RP) without residual vision. Further, the temporal dynamics of learning peripheral and central prosthetic vision are similar. Therefore, development of a peripheral retinal prosthesis and early implantation to alleviate VF constriction in RP should be considered to extend the target group and the time of benefit for potential retinal prosthesis implantees.

Nasal valve evaluation in the Mexican-Hispanic (mestizo) nose.

PubMed

Jasso-Ramírez, Elizabeth; Sánchez Y Béjar, Fernando; Arcaute Aizpuru, Fernando; Maulen Radován, Irene E; de la Garza Hesles, Héctor

2018-04-01

Our aim in this study was to determine the angle of the internal nasal valve in Mexican patients with the "mestizo nose" feature and without nasal obstructive symptoms. The work was prospective, comparative, and observational in nature and included patients >14 years of age who were seen in the Otolaryngology Department at the Los Angeles Lomas Hospital between April and May 2016. The angle of the internal nasal valve was measured in 30 patients without obstructive symptoms. Endoscopic examination was performed with a 0° endoscope framed with tape at a 13-mm distance from the endoscope's tip, and digital photographs of the internal nasal valve were taken. The measurement of the angle of the internal nasal valve was made in sexagesimal degrees using Golden Ratio v3.1 (2012) software. Statistical analysis was performed using Excel v15.13.3. The angles of the internal nasal valve of the patients were (mean ± standard deviation) 24.07 ± 4.8° for the right nasal cavity and 25.07 ± 5.0° for the left nasal cavity, wider than the angle reported in the normal Caucasian nose established in the literature. According to our results, the Mexican-Hispanic mestizo nose has a wider angle in the internal nasal valve than that considered normal in the literature (10°-15°). We believe it is necessary to undertake a second study and add an airflow resistance measurement with a rhinomanometry procedure so we can compare the results with those in the Caucasian population. © 2018 ARS-AAOA, LLC.

Influence of magnification and superimposition of structures on cephalometric diagnosis.

PubMed

Paula, Leonardo Koerich de; Solon-de-Mello, Priscilla de Almeida; Mattos, Claudia Trindade; Ruellas, Antônio Carlos de Oliveira; Sant'Anna, Eduardo Franzotti

2015-01-01

The purpose of this study was to assess the influence of magnification and superimposition of structures on CBCT-generated lateral cephalometric radiographs (LCR) using different segments of the cranium. CBCT scans of 10 patients were selected. Four LCR were generated using Dolphin Imaging(r) software: full-face, right side, left side and center of the head. A total of 40 images were imported into Radiocef Studio 2(r), and the angles of the most common cephalometric analyses were traced by the same observer twice and within a 10-day interval. Statistical analyses included intraexaminer agreement and comparison between methods by means of intraclass correlation coefficient (ICC) and Bland-Altman agreement tests. Intraexaminer agreement of the angles assessed by ICC was excellent (> 0.90) for 83% of measurements, good (between 0.75 and 0.90) for 15%, and moderate (between 0.50 and 0.75) for 2% of measurements. The comparison between methods by ICC was excellent for 68% of measurements, good for 26%, and moderate for 6%. Variables presenting wider confidence intervals (> 6o) in the Bland-Altman tests, in intraexaminer assessment, were: mandibular incisor angle, maxillary incisor angle, and occlusal plane angle. And in comparison methods the variables with wider confidence interval were: mandibular incisor, maxillary incisor, GoGn, occlusal plane angle, Frankfort horizontal plane (FHP), and CoA. Superimposition of structures seemed to influence the results more than magnification, and neither one of them significantly influenced the measurements. Considerable individual variability may occur, especially for mandibular and maxillary incisors, FHP and occlusal plane.

Characterization and Discrimination of Selected Vegetation Canopies from Field Observations of Bidirectional Reflectances. M.S. Thesis

NASA Technical Reports Server (NTRS)

Donovan, Sheila

1985-01-01

A full evaluation of the bidirectional reflectance properties of different vegetated surfaces was limited in past studies by instrumental inadequacies. With the development of the PARABOLA, it is now possible to sample reflectances from a large number of view angles in a short period of time, maintaining an almost constant solar zenith angle. PARABOLA data collected over five different canopies in Texas are analyzed. The objective of this investigation was to evaluate the intercanopy and intracanopy differences in bidirectional reflectance patterns. Particular attention was given to the separability of canopy types using different view angles for the red and the near infrared (NIR) spectral bands. Comparisons were repeated for different solar zenith angles. Statistical and other quantitative techniques were used to assess these differences. For the canopies investigated, the greatest reflectances were found in the backscatter direction for both bands. Canopy discrimination was found to vary with both view angle and the spectral reflectance band considered, the forward scatter view angles being most suited to observations in the NIR and backscatter view angles giving better results in the red band. Because of different leaf angle distribution characteristics, discrimination was found to be better at small solar zenith angles in both spectral bands.

Fabrication and investigation of the bionic curved visual microlens array films

NASA Astrophysics Data System (ADS)

Kuo, Wen-Kai; Lin, Syuan-You; Hsu, Sheng-Wei; Yu, Hsin Her

2017-04-01

The compound eyes of insects are smaller, lighter, and have a wider field of view and high sensitivity to moving targets. In recent years, these advantages have attracted many researchers to develop minimized optical devices. In this study, a high performance microlens was fabricated, mimicking the biological visual feature. Polystyrene (PS) microspheres were synthesized by dispersion polymerization first, and then a close-packed monolayer of PS microspheres was assembled by the Langmuir-Blodgett (LB) deposition method. Following this, a 2D polydimethylsiloxane (PDMS) concave mold was fabricated by a soft lithography technique. Different aperture sizes of poly(methyl methacrylate) (PMMA) curved microlens array replicated films were prepared using traditional Chinese medicine cupping tool with a temperature-controllable hot plate, which eliminated the need for inconvenient metal modeling. The optical performance of the curved microlens films were evaluated by a system of optical microscopy (OM) and a home-made image capture charge-coupled device (CCD). The field of view (FOV) and the light intensity distribution of the curved microlens array were also investigated. We found that a broader field of view corresponded to a smaller aperture size of the curved microlens films, as the convex heights of the films are identical. The resolution of the curved microlens films was not affected by their aperture sizes, but was determined by their interommatidial angle and the diameter of the microlens.

Measurements of the reflection factor of flat ground surfaces

NASA Technical Reports Server (NTRS)

Ventres, C. S.; Myles, M. M.; Ver, I. L.

1977-01-01

Measurements are made of the reflection factors of asphalt, concrete, and sod at oblique angles of incidence. Initial measurements were carried out in an anechoic chamber to eliminate the effects of wind and temperature gradients. These were followed by measurements made outdoors over a wider frequency range. Data are presented for the magnitudes of the reflection factors of asphalt, concrete, and sod at angles of incidence of 38 deg and 45 deg.

BOREAS RSS-2 Level-1B ASAS Image Data: At-Sensor Radiance in BSQ Format

NASA Technical Reports Server (NTRS)

Russell, C.; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Dabney, P. W.; Kovalick, W.; Graham, D.; Bur, Michael; Irons, James R.; Tierney, M.

2000-01-01

The BOREAS RSS-2 team used the ASAS instrument, mounted on the NASA C-130 aircraft, to create at-sensor radiance images of various sites as a function of spectral wavelength, view geometry (combinations of view zenith angle, view azimuth angle, solar zenith angle, and solar azimuth angle), and altitude. The level-1b ASAS images of the BOREAS study areas were collected from April to September 1994 and March to July 1996.

Long-Lag, Wide-pulse Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Norris, J. P.; Bonnell, J. T.; Kazanas, D.; Scargie, J. D.; Hakkila, J.; Giblin, T. W.

2005-01-01

The best available probe of the early phase of gamma-ray burst (GRB) jet attributes is the prompt gamma-ray emission, in which several intrinsic and extrinsic variables determine observed GRB pulse evolution, including at least: jet opening angle, profiles of Lorentz factor and matter/field density, distance of emission region from central source, and viewing angle. Bright, usually complex bursts have many narrow pulses that are difficult to model due to overlap. However, the relatively simple, long spectral lag, wide-pulse bursts may have simpler physics and are easier to model. We have analyzed the temporal and spectral behavior of wide pulses in 24 long-lag bursts from the BATSE sample, using a pulse model with two shape parameters - width and asymmetry - and the Band spectral model with three shape parameters. We find that pulses in long-lag bursts are distinguished both temporally and spectrally from those in bright bursts: the pulses in long spectral lag bursts are few in number, and approximately 100 times wider (10s of seconds), have systemtically lower peaks in nu*F(nu), harder low-energy spectra and softer high-energy spectra. These five pulse descriptors are essentially uncorrelated for our long-lag sample, suggesting that at least approximately 5 parameters are needed to model burst temporal and spectral behavior, roughly commensurate with the theoretical phase space. However, we do find that pulse width is strongly correlated with spectral lag; hence these two parameters may be viewed as mutual surrogates. The prevalence of long-lag bursts near the BATSE trigger threshold, their predominantly low nu*F(nu) spectral peaks, and relatively steep upper power-law spectral indices indicate that Swiift will detect many such bursts.

Simulations of Convection Zone Flows and Measurements from Multiple Viewing Angles

NASA Technical Reports Server (NTRS)

Duvall, Thomas L.; Hanasoge, Shravan

2011-01-01

A deep-focusing time-distance measurement technique has been applied to linear acoustic simulations of a solar interior perturbed by convective flows. The simulations are for the full sphere for r/R greater than 0.2. From these it is straightforward to simulate the observations from different viewing angles and to test how multiple viewing angles enhance detectibility. Some initial results will be presented.

The development of practice professional development plans from the postgraduate education allowance: a discussion of the causes and implications.

PubMed

Cornford, C S

2001-01-01

Practice professional development plans (PPDPs) began to replace the Postgraduate Education Allowance (PGEA) for general practitioners in England and Wales from April 2000. The origin of this change lies with those with educational expertise who have been concerned that the PGEA fails to encourage GPs to define their own learning needs, fails to encourage practice-based learning and fails to influence their working behaviour. The policy has been influenced however, by wider political developments which view PPDPs as a means to ensure national standards are met, to reassure the public, provide uniformity and deal with underperforming doctors. This mixture of influences has resulted in conflicting areas within PPDPs. There are different emphases on whether learning needs should be defined from the perspective of the individual or from the perspective of wider needs within the NHS. There are conflicting views about the desirability of multi- or uniprofessional learning and conflicting views about whether PPDPs are appropriate for dealing with failing doctors. PPDPs are based on a particular theory of adult learning - andragogy - which arguably fails to account for wider, richer and more significant forms of learning.

Esthetic smile preferences and the orientation of the maxillary occlusal plane.

PubMed

Kattadiyil, Mathew T; Goodacre, Charles J; Naylor, W Patrick; Maveli, Thomas C

2012-12-01

The anteroposterior orientation of the maxillary occlusal plane has an important role in the creation, assessment, and perception of an esthetic smile. However, the effect of the angle at which this plane is visualized (the viewing angle) in a broad smile has not been quantified. The purpose of this study was to assess the esthetic preferences of dental professionals and nondentists by using 3 viewing angles of the anteroposterior orientation of the maxillary occlusal plane. After Institutional Review Board approval, standardized digital photographic images of the smiles of 100 participants were recorded by simultaneously triggering 3 cameras set at different viewing angles. The top camera was positioned 10 degrees above the occlusal plane (camera #1, Top view); the center camera was positioned at the level of the occlusal plane (camera #2, Center view); and the bottom camera was located 10 degrees below the occlusal plane (camera #3, Bottom view). Forty-two dental professionals and 31 nondentists (persons from the general population) independently evaluated digital images of each participant's smile captured from the Top view, Center view, and Bottom view. The 73 evaluators were asked individually through a questionnaire to rank the 3 photographic images of each patient as 'most pleasing,' 'somewhat pleasing,' or 'least pleasing,' with most pleasing being the most esthetic view and the preferred orientation of the occlusal plane. The resulting esthetic preferences were statistically analyzed by using the Friedman test. In addition, the participants were asked to rank their own images from the 3 viewing angles as 'most pleasing,' 'somewhat pleasing,' and 'least pleasing.' The 73 evaluators found statistically significant differences in the esthetic preferences between the Top and Bottom views and between the Center and Bottom views (P<.001). No significant differences were found between the Top and Center views. The Top position was marginally preferred over the Center, and both were significantly preferred over the Bottom position. When the participants evaluated their own smiles, a significantly greater number (P< .001) preferred the Top view over the Center or the Bottom views. No significant differences were found in preferences based on the demographics of the evaluators when comparing age, education, gender, profession, and race. The esthetic preference for the maxillary occlusal plane was influenced by the viewing angle with the higher (Top) and center views preferred by both dental and nondental evaluators. The participants themselves preferred the higher view of their smile significantly more often than the center or lower angle views (P<.001). Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Large-viewing-angle electroholography by space projection

NASA Astrophysics Data System (ADS)

Sato, Koki; Obana, Kazuki; Okumura, Toshimichi; Kanaoka, Takumi; Nishikawa, Satoko; Takano, Kunihiko

2004-06-01

The specification of hologram image is the full parallax 3D image. In this case we can get more natural 3D image because focusing and convergence are coincident each other. We try to get practical electro-holography system because for conventional electro-holography the image viewing angle is very small. This is due to the limited display pixel size. Now we are developing new method for large viewing angle by space projection method. White color laser is irradiated to single DMD panel ( time shared CGH of RGB three colors ). 3D space screen constructed by very small water particle is used to reconstruct the 3D image with large viewing angle by scattering of water particle.

Increased horizontal viewing zone angle of a hologram by resolution redistribution of a spatial light modulator.

PubMed

Takaki, Yasuhiro; Hayashi, Yuki

2008-07-01

The narrow viewing zone angle is one of the problems associated with electronic holography. We propose a technique that enables the ratio of horizontal and vertical resolutions of a spatial light modulator (SLM) to be altered. This technique increases the horizontal resolution of a SLM several times, so that the horizontal viewing zone angle is also increased several times. A SLM illuminated by a slanted point light source array is imaged by a 4f imaging system in which a horizontal slit is located on the Fourier plane. We show that the horizontal resolution was increased four times and that the horizontal viewing zone angle was increased approximately four times.

C-band backscattering from corn canopies

NASA Technical Reports Server (NTRS)

Daughtry, C. S. T.; Ranson, K. J.; Biehl, L. L.

1991-01-01

A frequency-modulatad continuous-wave C-band (4.8 GHz) scatterometer was mounted on an aerial lift truck, and backscatter coefficients of corn (Zea mays L.) were acquired as functions of polarizations, view angles, and row directions. As phytomass and green-leaf area index increased, the backscatter also increased. Near anthesis, when the canopies were fully developed, the major scattering elements were located in the upper 1 m of the 2.8 m tall canopy and little backscatter was measured below that level for view angles of 30 deg or greater. C-band backscatter data could provide information to monitor tillage operations at small view zenith angles and vegetation at large view zenith angles.

The effect of viewing angle on the spectral behavior of a Gd plasma source near 6.7 nm

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Gorman, Colm; Li Bowen; Cummins, Thomas

2012-04-02

We have demonstrated the effect of viewing angle on the extreme ultraviolet (EUV) emission spectra of gadolinium (Gd) near 6.7 nm. The spectra are shown to have a strong dependence on viewing angle when produced with a laser pulse duration of 10 ns, which may be attributed to absorption by low ion stages of Gd and an angular variation in the ion distribution. Absorption effects are less pronounced at a 150-ps pulse duration due to reduced opacity resulting from plasma expansion. Thus for evaluating source intensity, it is necessary to allow for variation with both viewing angle and target orientation.

Automated comprehensive Adolescent Idiopathic Scoliosis assessment using MVC-Net.

PubMed

Wu, Hongbo; Bailey, Chris; Rasoulinejad, Parham; Li, Shuo

2018-05-18

Automated quantitative estimation of spinal curvature is an important task for the ongoing evaluation and treatment planning of Adolescent Idiopathic Scoliosis (AIS). It solves the widely accepted disadvantage of manual Cobb angle measurement (time-consuming and unreliable) which is currently the gold standard for AIS assessment. Attempts have been made to improve the reliability of automated Cobb angle estimation. However, it is very challenging to achieve accurate and robust estimation of Cobb angles due to the need for correctly identifying all the required vertebrae in both Anterior-posterior (AP) and Lateral (LAT) view x-rays. The challenge is especially evident in LAT x-ray where occlusion of vertebrae by the ribcage occurs. We therefore propose a novel Multi-View Correlation Network (MVC-Net) architecture that can provide a fully automated end-to-end framework for spinal curvature estimation in multi-view (both AP and LAT) x-rays. The proposed MVC-Net uses our newly designed multi-view convolution layers to incorporate joint features of multi-view x-rays, which allows the network to mitigate the occlusion problem by utilizing the structural dependencies of the two views. The MVC-Net consists of three closely-linked components: (1) a series of X-modules for joint representation of spinal structure (2) a Spinal Landmark Estimator network for robust spinal landmark estimation, and (3) a Cobb Angle Estimator network for accurate Cobb Angles estimation. By utilizing an iterative multi-task training algorithm to train the Spinal Landmark Estimator and Cobb Angle Estimator in tandem, the MVC-Net leverages the multi-task relationship between landmark and angle estimation to reliably detect all the required vertebrae for accurate Cobb angles estimation. Experimental results on 526 x-ray images from 154 patients show an impressive 4.04° Circular Mean Absolute Error (CMAE) in AP Cobb angle and 4.07° CMAE in LAT Cobb angle estimation, which demonstrates the MVC-Net's capability of robust and accurate estimation of Cobb angles in multi-view x-rays. Our method therefore provides clinicians with a framework for efficient, accurate, and reliable estimation of spinal curvature for comprehensive AIS assessment. Copyright © 2018. Published by Elsevier B.V.

Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle.

PubMed

Qin, Zong; Wang, Kai; Chen, Fei; Luo, Xiaobing; Liu, Sheng

2010-08-02

In this research, the condition for uniform lighting generated by array of LEDs with large view angle was studied. The luminous intensity distribution of LED is not monotone decreasing with view angle. A LED with freeform lens was designed as an example for analysis. In a system based on LEDs designed in house with a thickness of 20mm and rectangular arrangement, the condition for uniform lighting was derived and the analytical results demonstrated that the uniformity was not decreasing monotonously with the increasing of LED-to-LED spacing. The illuminance uniformities were calculated with Monte Carlo ray tracing simulations and the uniformity was found to increase with the increasing of certain LED-to-LED spacings anomalously. Another type of large view angle LED and different arrangements were discussed in addition. Both analysis and simulation results showed that the method is available for LED array lighting system design on the basis of large view angle LED..

View angle dependence of cloud optical thicknesses retrieved by MODIS

NASA Technical Reports Server (NTRS)

Marshak, Alexander; Varnai, Tamas

2005-01-01

This study examines whether cloud inhomogeneity influences the view angle dependence of MODIS cloud optical thickness (tau) retrieval results. The degree of cloud inhomogeneity is characterized through the local gradient in 11 microns brightness temperature. The analysis of liquid phase clouds in a one year long global dataset of Collection 4 MODIS data reveals that while optical thickness retrievals give remarkably consistent results for all view directions if clouds are homogeneous, they give much higher tau-values for oblique views than for overhead views if clouds are inhomogeneous and the sun is fairly oblique. For solar zenith angles larger than 55deg, the mean optical thickness retrieved for the most inhomogeneous third of cloudy pixels is more than 30% higher for oblique views than for overhead views. After considering a variety of possible scenarios, the paper concludes that the most likely reason for the increase lies in three-dimensional radiative interactions that are not considered in current, one-dimensional retrieval algorithms. Namely, the radiative effect of cloud sides viewed at oblique angles seems to contribute most to the enhanced tau-values. The results presented here will help understand cloud retrieval uncertainties related to cloud inhomogeneity. They complement the uncertainty estimates that will start accompanying MODIS cloud products in Collection 5 and may eventually help correct for the observed view angle dependent biases.

Color dependence with horizontal-viewing angle and colorimetric characterization of two displays using different backlighting

NASA Astrophysics Data System (ADS)

Castro, José J.; Pozo, Antonio M.; Rubiño, Manuel

2013-11-01

In this work we studied the color dependence with a horizontal-viewing angle and colorimetric characterization of two liquid-crystal displays (LCD) using two different backlighting: Cold Cathode Fluorescent Lamps (CCFLs) and light-emitting diodes (LEDs). The LCDs studied had identical resolution, size, and technology (TFT - thin film transistor). The colorimetric measurements were made with the spectroradiometer SpectraScan PR-650 following the procedure recommended in the European guideline EN 61747-6. For each display, we measured at the centre of the screen the chromaticity coordinates at horizontal viewing angles of 0, 20, 40, 60 and 80 degrees for the achromatic (A), red (R), green (G) and blue (B) channels. Results showed a greater color-gamut area for the display with LED backlight, compared with the CCFL backlight, showing a greater range of colors perceptible by human vision. This color-gamut area diminished with viewing angle for both displays. Higher differences between trends for viewing angles were observed in the LED-backlight, especially for the R- and G-channels, demonstrating a higher variability of the chromaticity coordinates with viewing angle. The best additivity was reached by the LED-backlight display (a lower error percentage). LED-backlight display provided better color performance of visualization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davies, R.

The spatial autocorrelation functions of broad-band longwave and shortwave radiances measured by the Earth Radiation Budget Experiment (ERBE) are analyzed as a function of view angle in an investigation of the general effects of scene inhomogeneity on radiation. For nadir views, the correlation distance of the autocorrelation function is about 900 km for longwave radiance and about 500 km for shortwave radiance, consistent with higher degrees of freedom in shortwave reflection. Both functions rise monotonically with view angle, but there is a substantial difference in the relative angular dependence of the shortwave and longwave functions, especially for view angles lessmore » than 50 deg. In this range, the increase with angle of the longwave functions is found to depend only on the expansion of pixel area with angle, whereas the shortwave functions show an additional dependence on angle that is attributed to the occlusion of inhomogeneities by cloud height variations. Beyond a view angle of about 50 deg, both longwave and shortwave functions appear to be affected by cloud sides. The shortwave autocorrelation functions do not satisfy the principle of directional reciprocity, thereby proving that the average scene is horizontally inhomogeneous over the scale of an ERBE pixel (1500 sq km). Coarse stratification of the measurements by cloud amount, however, indicates that the average cloud-free scene does satisfy directional reciprocity on this scale.« less

Flight Integral Field Spectrograph (IFS) Optical Design for WFIRST Coronagraphic Exoplanet Demonstration

NASA Technical Reports Server (NTRS)

Gong, Qian; Groff, Tyler D.; Zimmerman, Neil; Mandell, Avi; McElwain, Michael; Rizzo, Maxime; Saxena, Prabal

2017-01-01

Based on the experience from Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST, we have moved to the flight instrument design phase. The specifications for flight IFS have similarities and differences from the prototype. This paper starts with the science and system requirement, discusses a number of critical trade-offs: such as IFS type selection, lenslet array shape and layout versus detector pixel accuracy, how to accommodate the larger Field Of View (FOV) and wider wavelength band for a potential add-on StarShade occulter. Finally, the traditional geometric optical design is also investigated and traded: reflective versus refractive, telecentric versus non-telecentric relay. The relay before the lenslet array controls the chief angle distribution on the lenslet array. Our previous paper has addressed how the relay design combined with lenslet arraypinhole mask can further compress the residual star light and increase the contrast. Finally, a complete phase A IFS optical design is presented.

The cam impinging femur has multiple morphologic abnormalities.

PubMed

Ellis, Andrew R; Noble, Philip C; Schroder, Steven J; Thompson, Matthew T; Stocks, Gregory W

2011-09-01

This study was performed to establish whether the "cam" impinging femur has a single deformity of the head-neck junction or multiple abnormalities. Average dimensions (anteversion angle, α angle of Notzli, β angle of Beaulé, normalized anterior head offset) were compared between normal and impinging femora. The results demonstrated that impinging femora had wider necks, larger heads, and decreased head-neck ratios. There was no difference in neck-shaft angle or anteversion angle. Forty-six percent of impinging femora had significant posterior head displacement (>2mm), which averaged 1.93 mm for the cam impinging group, and 0.78 mm for the normal group. In conclusion, surgical treatment limited to localized recontouring of the head-neck profile may fail to address significant components of the underlying abnormality. Copyright © 2011 Elsevier Inc. All rights reserved.

PTSD in Limb Trauma and Recovery

DTIC Science & Technology

2008-10-16

field of view, much greater image fidelity and more comfortable viewing than the Emagin head-mounted display, and is well-suited to deployment in a...run on display platforms other than the eMagin Head-Mounted Display (HMD). This will include Brown University’s Cave, an eight- foot immersive VR...Samsung display provides wider field of view, much greater image fidelity and more comfortable viewing than the Emagin head-mounted display, and is

What convention is used for the illumination and view angles?

Atmospheric Science Data Center

2014-12-08

... Azimuth angles are measured clockwise from the direction of travel to local north. For both the Sun and cameras, azimuth describes the ... to the equator, because of its morning equator crossing time. Additionally, the difference in view and solar azimuth angle will be near ...

Digital 3D holographic display using scattering layers for enhanced viewing angle and image size

NASA Astrophysics Data System (ADS)

Yu, Hyeonseung; Lee, KyeoReh; Park, Jongchan; Park, YongKeun

2017-05-01

In digital 3D holographic displays, the generation of realistic 3D images has been hindered by limited viewing angle and image size. Here we demonstrate a digital 3D holographic display using volume speckle fields produced by scattering layers in which both the viewing angle and the image size are greatly enhanced. Although volume speckle fields exhibit random distributions, the transmitted speckle fields have a linear and deterministic relationship with the input field. By modulating the incident wavefront with a digital micro-mirror device, volume speckle patterns are controlled to generate 3D images of micrometer-size optical foci with 35° viewing angle in a volume of 2 cm × 2 cm × 2 cm.

Wide-angle vision for road views

NASA Astrophysics Data System (ADS)

Huang, F.; Fehrs, K.-K.; Hartmann, G.; Klette, R.

2013-03-01

The field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.

Responding to the Challenges of KM Education in the LIS Sector: Some Academic and Professional Perspectives

ERIC Educational Resources Information Center

Hazeri, Afsaneh; Martin, Bill

2009-01-01

As a newly emerging field of study, KM education is faced with significant challenges which continue to evolve. Informed by wider organisational perspectives, this paper presents the findings of recent research into this field. The first part of the research was in the form of an online survey canvassing the views of the wider LIS community on the…

Comparison of endoscopic transnasal and transoral approaches to the craniovertebral junction.

PubMed

Seker, Askin; Inoue, Kohei; Osawa, Shigeyuki; Akakin, Akin; Kilic, Turker; Rhoton, Albert L

2010-12-01

The study compared the endoscopic anatomy of the transnasal and transoral approaches to the craniovertebral junction (CVJ). Structures examined and compared with both the straight and angled telescopes in 10 cadaveric specimens included the pharyngeal walls and adjacent musculature, resected anterior arch of the axis and odontoid, cruciform, axial, and apical ligaments, clival and dural openings, and the intradural exposure. There is considerable overlap at the pharyngeal level in the structures that can be viewed by the transoral and transnasal routes. The transoral approach provides a wider corridor with less restricted manipulation of instruments than the transnasal approach, but the transnasal approach provides a better view of the clivus, upper part of the CVJ, and the structures posterior to the removed odontoid and anterior arch of C1. Combining the two approaches provides significantly better access to the midline anterior CVJ than either approach alone, allows the scopes to be advanced in one cavity and the surgical instruments in the other cavity, and reduces the need to split the palate, tongue, or mandible in order to reach the target area. The transnasal approach also allows access to the superior part of the occipital condyles, paraclival areas, and hypoglossal canals without removal of the condyles, but these structures can be exposed by the transoral route only after at least partial removal of the condyles. The endoscopic transoral and transnasal approaches to the CVJ should be viewed as complementary routes as opposed to strict alternatives. Copyright © 2010 Elsevier Inc. All rights reserved.

10. 22'X34' original blueprint, VariableAngle Launcher, 'SIDE VIEW CAMERA CARSTEEL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. 22'X34' original blueprint, Variable-Angle Launcher, 'SIDE VIEW CAMERA CAR-STEEL FRAME AND AXLES' drawn at 1/2'=1'-0'. (BOURD Sketch # 209124). - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Two Perspectives on Forest Fire

NASA Technical Reports Server (NTRS)

2002-01-01

Multi-angle Imaging Spectroradiometer (MISR) images of smoke plumes from wildfires in western Montana acquired on August 14, 2000. A portion of Flathead Lake is visible at the top, and the Bitterroot Range traverses the images. The left view is from MISR's vertical-viewing (nadir) camera. The right view is from the camera that looks forward at a steep angle (60 degrees). The smoke location and extent are far more visible when seen at this highly oblique angle. However, vegetation is much darker in the forward view. A brown burn scar is located nearly in the exact center of the nadir image, while in the high-angle view it is shrouded in smoke. Also visible in the center and upper right of the images, and more obvious in the clearer nadir view, are checkerboard patterns on the surface associated with land ownership boundaries and logging. Compare these images with the high resolution infrared imagery captured nearby by Landsat 7 half an hour earlier. Images by NASA/GSFC/JPL, MISR Science Team.

Spatial autocorrelation of radiation measured by the Earth Radiation Budget Experiment: Scene inhomogeneity and reciprocity violation

NASA Technical Reports Server (NTRS)

Davies, Roger

1994-01-01

The spatial autocorrelation functions of broad-band longwave and shortwave radiances measured by the Earth Radiation Budget Experiment (ERBE) are analyzed as a function of view angle in an investigation of the general effects of scene inhomogeneity on radiation. For nadir views, the correlation distance of the autocorrelation function is about 900 km for longwave radiance and about 500 km for shortwave radiance, consistent with higher degrees of freedom in shortwave reflection. Both functions rise monotonically with view angle, but there is a substantial difference in the relative angular dependence of the shortwave and longwave functions, especially for view angles less than 50 deg. In this range, the increase with angle of the longwave functions is found to depend only on the expansion of pixel area with angle, whereas the shortwave functions show an additional dependence on angle that is attributed to the occlusion of inhomogeneities by cloud height variations. Beyond a view angle of about 50 deg, both longwave and shortwave functions appear to be affected by cloud sides. The shortwave autocorrelation functions do not satisfy the principle of directional reciprocity, thereby proving that the average scene is horizontally inhomogeneous over the scale of an ERBE pixel (1500 sq km). Coarse stratification of the measurements by cloud amount, however, indicates that the average cloud-free scene does satisfy directional reciprocity on this scale.

Application of AI techniques to infer vegetation characteristics from directional reflectance(s)

NASA Technical Reports Server (NTRS)

Kimes, D. S.; Smith, J. A.; Harrison, P. A.; Harrison, P. R.

1994-01-01

Traditionally, the remote sensing community has relied totally on spectral knowledge to extract vegetation characteristics. However, there are other knowledge bases (KB's) that can be used to significantly improve the accuracy and robustness of inference techniques. Using AI (artificial intelligence) techniques a KB system (VEG) was developed that integrates input spectral measurements with diverse KB's. These KB's consist of data sets of directional reflectance measurements, knowledge from literature, and knowledge from experts which are combined into an intelligent and efficient system for making vegetation inferences. VEG accepts spectral data of an unknown target as input, determines the best techniques for inferring the desired vegetation characteristic(s), applies the techniques to the target data, and provides a rigorous estimate of the accuracy of the inference. VEG was developed to: infer spectral hemispherical reflectance from any combination of nadir and/or off-nadir view angles; infer percent ground cover from any combination of nadir and/or off-nadir view angles; infer unknown view angle(s) from known view angle(s) (known as view angle extension); and discriminate between user defined vegetation classes using spectral and directional reflectance relationships developed from an automated learning algorithm. The errors for these techniques were generally very good ranging between 2 to 15% (proportional root mean square). The system is designed to aid scientists in developing, testing, and applying new inference techniques using directional reflectance data.

Miranda

NASA Image and Video Library

1999-08-24

One wide-angle and eight narrow-angle camera images of Miranda, taken by NASA Voyager 2, were combined in this view. The controlled mosaic was transformed to an orthographic view centered on the south pole.

Measuring the Viewing Angle of GW170817 with Electromagnetic and Gravitational Waves

NASA Astrophysics Data System (ADS)

Finstad, Daniel; De, Soumi; Brown, Duncan A.; Berger, Edo; Biwer, Christopher M.

2018-06-01

The joint detection of gravitational waves (GWs) and electromagnetic (EM) radiation from the binary neutron star merger GW170817 ushered in a new era of multi-messenger astronomy. Joint GW–EM observations can be used to measure the parameters of the binary with better precision than either observation alone. Here, we use joint GW–EM observations to measure the viewing angle of GW170817, the angle between the binary’s angular momentum and the line of sight. We combine a direct measurement of the distance to the host galaxy of GW170817 (NGC 4993) of 40.7 ± 2.36 Mpc with the Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo GW data and find that the viewing angle is {32}-13+10 +/- 1.7 degrees (90% confidence, statistical, and systematic errors). We place a conservative lower limit on the viewing angle of ≥13°, which is robust to the choice of prior. This measurement provides a constraint on models of the prompt γ-ray and radio/X-ray afterglow emission associated with the merger; for example, it is consistent with the off-axis viewing angle inferred for a structured jet model. We provide for the first time the full posterior samples from Bayesian parameter estimation of LIGO/Virgo data to enable further analysis by the community.

Gender, Militarism and the View of the Future: Students' Views on the Introduction of the Civilian Service in Serbia

ERIC Educational Resources Information Center

Milojevic, Ivana; Markov, Slobodanka

2008-01-01

What are some of the obstacles to demilitarization of society? What role does worldview in general, and views of gender, future and peace in particular, play in this process? What could be some aspects of the intervention when educating students and the wider community for peace? This article discusses the results from a pilot study that…

Design considerations for a backlight with switchable viewing angles

NASA Astrophysics Data System (ADS)

Fujieda, Ichiro; Takagi, Yoshihiko; Rahadian, Fanny

2006-08-01

Small-sized liquid crystal displays are widely used for mobile applications such as cell phones. Electronic control of a viewing angle range is desired in order to maintain privacy for viewing in public as well as to provide wide viewing angles for solitary viewing. Conventionally, a polymer-dispersed liquid crystal (PDLC) panel is inserted between a backlight and a liquid crystal panel. The PDLC layer either transmits or scatters the light from the backlight, thus providing an electronic control of viewing angles. However, such a display system is obviously thick and expensive. Here, we propose to place an electronically-controlled, light-deflecting device between an LED and a light-guide of a backlight. For example, a liquid crystal lens is investigated for other applications and its focal length is controlled electronically. A liquid crystal phase grating either transmits or diffracts an incoming light depending on whether or not a periodic phase distribution is formed inside its liquid crystal layer. A bias applied to such a device will control the angular distribution of the light propagating inside a light-guide. Output couplers built in the light-guide extract the propagating light to outside. They can be V-shaped grooves, pyramids, or any other structures that can refract, reflect or diffract light. When any of such interactions occur, the output couplers translate the changes in the propagation angles into the angular distribution of the output light. Hence the viewing-angle characteristic can be switched. The designs of the output couplers and the LC devices are important for such a backlight system.

Modeling contact angle hysteresis of a liquid droplet sitting on a cosine wave-like pattern surface.

PubMed

Promraksa, Arwut; Chen, Li-Jen

2012-10-15

A liquid droplet sitting on a hydrophobic surface with a cosine wave-like square-array pattern in the Wenzel state is simulated by using the Surface Evolver to determine the contact angle. For a fixed drop volume, multiple metastable states are obtained at two different surface roughnesses. Unusual and non-circular shape of the three-phase contact line of a liquid droplet sitting on the model surface is observed due to corrugation and distortion of the contact line by structure of the roughness. The contact angle varies along the contact line for each metastable state. The maximum and minimum contact angles among the multiple metastable states at a fixed viewing angle correspond to the advancing and the receding contact angles, respectively. It is interesting to observe that the advancing/receding contact angles (and contact angle hysteresis) are a function of viewing angle. In addition, the receding (or advancing) contact angles at different viewing angles are determined at different metastable states. The contact angle of minimum energy among the multiple metastable states is defined as the most stable (equilibrium) contact angle. The Wenzel model is not able to describe the contact angle along the three-phase contact line. The contact angle hysteresis at different drop volumes is determined. The number of the metastable states increases with increasing drop volume. Drop volume effect on the contact angles is also discussed. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Matching the best viewing angle in depth cameras for biomass estimation based on poplar seedling geometry.

PubMed

Andújar, Dionisio; Fernández-Quintanilla, César; Dorado, José

2015-06-04

In energy crops for biomass production a proper plant structure is important to optimize wood yields. A precise crop characterization in early stages may contribute to the choice of proper cropping techniques. This study assesses the potential of the Microsoft Kinect for Windows v.1 sensor to determine the best viewing angle of the sensor to estimate the plant biomass based on poplar seedling geometry. Kinect Fusion algorithms were used to generate a 3D point cloud from the depth video stream. The sensor was mounted in different positions facing the tree in order to obtain depth (RGB-D) images from different angles. Individuals of two different ages, e.g., one month and one year old, were scanned. Four different viewing angles were compared: top view (0°), 45° downwards view, front view (90°) and ground upwards view (-45°). The ground-truth used to validate the sensor readings consisted of a destructive sampling in which the height, leaf area and biomass (dry weight basis) were measured in each individual plant. The depth image models agreed well with 45°, 90° and -45° measurements in one-year poplar trees. Good correlations (0.88 to 0.92) between dry biomass and the area measured with the Kinect were found. In addition, plant height was accurately estimated with a few centimeters error. The comparison between different viewing angles revealed that top views showed poorer results due to the fact the top leaves occluded the rest of the tree. However, the other views led to good results. Conversely, small poplars showed better correlations with actual parameters from the top view (0°). Therefore, although the Microsoft Kinect for Windows v.1 sensor provides good opportunities for biomass estimation, the viewing angle must be chosen taking into account the developmental stage of the crop and the desired parameters. The results of this study indicate that Kinect is a promising tool for a rapid canopy characterization, i.e., for estimating crop biomass production, with several important advantages: low cost, low power needs and a high frame rate (frames per second) when dynamic measurements are required.

A see-through holographic head-mounted display with the large viewing angle

NASA Astrophysics Data System (ADS)

Chen, Zhidong; sang, Xinzhu; Lin, Qiaojun; Li, Jin; Yu, Xunbo; Gao, Xin; Yan, Binbin; Wang, Kuiru; Yu, Chongxiu; Xie, Songlin

2017-02-01

A novel solution for the large view angle holographic head-mounted display (HHMD) is presented. Divergent light is used for the hologram illumination to construct a large size three-dimensional object outside the display in a short distance. A designed project-type lens with large numerical aperture projects the object constructed by the hologram to its real location. The presented solution can realize a compact HHMD system with a large field of view. The basic principle and the structure of the system are described. An augmented reality (AR) prototype with the size of 50 mm×40 mm and the view angle above 60° is demonstrated.

Absorption spectroscopy and multi-angle scattering measurements in the visible spectral range for the geographic classification of Italian exravirgin olive oils

NASA Astrophysics Data System (ADS)

Mignani, Anna G.; Ciaccheri, Leonardo; Cimato, Antonio; Sani, Graziano; Smith, Peter R.

2004-03-01

Absorption spectroscopy and multi-angle scattering measurements in the visible spectral range are innovately used to analyze samples of extra virgin olive oils coming from selected areas of Tuscany, a famous Italian region for the production of extra virgin olive oil. The measured spectra are processed by means of the Principal Component Analysis method, so as to create a 3D map capable of clustering the Tuscan oils within the wider area of Italian extra virgin olive oils.

Visual Costs of the Inhomogeneity of Luminance and Contrast by Viewing LCD-TFT Screens Off-Axis.

PubMed

Ziefle, Martina; Groeger, Thomas; Sommer, Dietmar

2003-01-01

In this study the anisotropic characteristics of TFT-LCD (Thin-Film-Transistor-Liquid Crystal Display) screens were examined. Anisotropy occurs as the distribution of luminance and contrast changes over the screen surface due to different viewing angles. On the basis of detailed photometric measurements the detection performance in a visual reaction task was measured in different viewing conditions. Viewing angle (0 degrees, frontal view; 30 degrees, off-axis; 50 degrees, off-axis) as well as ambient lighting (a dark or illuminated room) were varied. Reaction times and accuracy of detection performance were recorded. Results showed TFT's anisotropy to be a crucial factor deteriorating performance. With an increasing viewing angle performance decreased. It is concluded that TFT's anisotropy is a limiting factor for overall suitability and usefulness of this new display technology.

Preferred viewing distance of liquid crystal high-definition television.

PubMed

Lee, Der-Song

2012-01-01

This study explored the effect of TV size, illumination, and viewing angle on preferred viewing distance in high-definition liquid crystal display televisions (HDTV). Results showed that the mean preferred viewing distance was 2856 mm. TV size and illumination significantly affected preferred viewing distance. The larger the screen size, the greater the preferred viewing distance, at around 3-4 times the width of the screen (W). The greater the illumination, the greater the preferred viewing distance. Viewing angle also correlated significantly with preferred viewing distance. The more deflected from direct frontal view, the shorter the preferred viewing distance seemed to be. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Wide-field fundus imaging with trans-palpebral illumination.

PubMed

Toslak, Devrim; Thapa, Damber; Chen, Yanjun; Erol, Muhammet Kazim; Paul Chan, R V; Yao, Xincheng

2017-01-28

In conventional fundus imaging devices, transpupillary illumination is used for illuminating the inside of the eye. In this method, the illumination light is directed into the posterior segment of the eye through the cornea and passes the pupillary area. As a result of sharing the pupillary area for the illumination beam and observation path, pupil dilation is typically necessary for wide-angle fundus examination, and the field of view is inherently limited. An alternative approach is to deliver light from the sclera. It is possible to image a wider retinal area with transcleral-illumination. However, the requirement of physical contact between the illumination probe and the sclera is a drawback of this method. We report here trans-palpebral illumination as a new method to deliver the light through the upper eyelid (palpebra). For this study, we used a 1.5 mm diameter fiber with a warm white LED light source. To illuminate the inside of the eye, the fiber illuminator was placed at the location corresponding to the pars plana region. A custom designed optical system was attached to a digital camera for retinal imaging. The optical system contained a 90 diopter ophthalmic lens and a 25 diopter relay lens. The ophthalmic lens collected light coming from the posterior of the eye and formed an aerial image between the ophthalmic and relay lenses. The aerial image was captured by the camera through the relay lens. An adequate illumination level was obtained to capture wide angle fundus images within ocular safety limits, defined by the ISO 15004-2: 2007 standard. This novel trans-palpebral illumination approach enables wide-angle fundus photography without eyeball contact and pupil dilation.

Light sources and output couplers for a backlight with switchable emission angles

NASA Astrophysics Data System (ADS)

Fujieda, Ichiro; Imai, Keita; Takagi, Yoshihiko

2007-09-01

For switching viewing angles of a liquid crystal display, we proposed to place a liquid crystal device between an LED and a light-guide of a backlight. The first key component for this configuration is a light source with electronically-controlled emission angles. Here, we construct such a device by stacking an optical film and a polymer-network liquid crystal (PNLC) cell on top of a chip-type LED. The optical film contains opaque parallel plates that limit the LED output in a narrow angular range. The PNLC cell either transmits or scatters the light emerging from the optical film. Experiment using a 15μm-thick PNLC cell shows that the angular distribution becomes 2.3 times wider by turning off the PNLC cell. We place this light source at one end of a light-guide so that the angular distribution of the light propagating inside is controlled. The second key component is some types of micro-strucrures built on the light-guide to out-couple the propagating light. We first attached various optical films on a light-guide surface. Although the angular distribution of the extracted light was switched successfully, light was mostly emitted into an oblique direction, approximately 60° from the plane normal. Next, we used a half-cylinder in place of the optical films. The curved surface of the cylinder was attached to the light-guide with a small amount of matching oil, which constituted an optical window. We measured that the angular distribution of the extracted light decreased to 35° FWHM from 62° FWHM by turning on the PNLC cell.

Comparison of tunnel variability between trans-portal and outside-in techniques in ACL reconstruction.

PubMed

Sim, Jae-Ang; Kim, Jong-Min; Lee, Sahnghoon; Bae, Ji-Yong; Seon, Jong-Keun

2017-04-01

Although trans-portal and outside-in techniques are commonly used for anatomical ACL reconstruction, there is very little information on variability in tunnel placement between two techniques. A total of 103 patients who received ACL reconstruction using trans-portal (50 patients) and outside-in techniques (53 patients) were included in the study. The ACL tunnel location, length and graft-femoral tunnel angle were analyzed using the 3D CT knee models, and we compared the location and length of the femoral and tibial tunnels, and graft bending angle between the two techniques. The variability in each technique regarding the tunnel location, length and graft tunnel angle using the range values was also compared. There were no differences in the average of femoral tunnel depth and height between the two groups. The ranges of femoral tunnel depth and height showed no difference between two groups (36 and 41 % in trans-portal technique vs. 32 and 41 % in outside-in technique). The average value and ranges of tibial tunnel location also showed similar results in two groups. The outside-in technique showed longer femoral tunnel than the trans-portal technique (34.0 vs. 36.8 mm, p = 0.001). The range of femoral tunnel was also wider in trans-portal technique than in outside-in technique. Although the outside-in technique showed significant acute graft bending angle than trans-portal technique in average values, the trans-portal technique showed wider ranges in graft bending angle than outside-in technique [ranges 73° (SD 13.6) vs. 53° (SD 10.7), respectively]. Although both trans-portal and outside-in techniques in ACL reconstruction can provide relatively consistent in femoral and tibial tunnel locations, trans-portal technique showed high variability in femoral tunnel length and graft bending angles than outside-in technique. Therefore, the outside-in technique in ACL reconstruction is considered as the effective method for surgeons to make more consistent femoral tunnel. III.

Examining view angle effects on leaf N estimation in wheat using field reflectance spectroscopy

NASA Astrophysics Data System (ADS)

Song, Xiao; Feng, Wei; He, Li; Xu, Duanyang; Zhang, Hai-Yan; Li, Xiao; Wang, Zhi-Jie; Coburn, Craig A.; Wang, Chen-Yang; Guo, Tian-Cai

2016-12-01

Real-time, nondestructive monitoring of crop nitrogen (N) status is a critical factor for precision N management during wheat production. Over a 3-year period, we analyzed different wheat cultivars grown under different experimental conditions in China and Canada and studied the effects of viewing angle on the relationships between various vegetation indices (VIs) and leaf nitrogen concentration (LNC) using hyperspectral data from 11 field experiments. The objective was to improve the prediction accuracy by minimizing the effects of viewing angle on LNC estimation to construct a novel vegetation index (VI) for use under different experimental conditions. We examined the stability of previously reported optimum VIs obtained from 13 traditional indices for estimating LNC at 13 viewing zenith angles (VZAs) in the solar principal plane (SPP). Backscattering direction showed better index performance than forward scattering direction. Red-edge VIs including modified normalized difference vegetation index (mND705), ratio index within the red edge region (RI-1dB) and normalized difference red edge index (NDRE) were highly correlated with LNC, as confirmed by high R2 determination coefficients. However, these common VIs tended to saturation, as the relationships strongly depended on experimental conditions. To overcome the influence of VZA on VIs, the chlorophyll- and LNC-sensitive NDRE index was divided by the floating-position water band index (FWBI) to generate the integrated narrow-band vegetation index. The highest correlation between the novel NDRE/FWBI parameter and LNC (R2 = 0.852) occurred at -10°, while the lowest correlation (R2 = 0.745) occurred at 60°. NDRE/FWBI was more highly correlated with LNC than existing commonly used VIs at an identical viewing zenith angle. Upon further analysis of angle combinations, our novel VI exhibited the best performance, with the best prediction accuracy at 0° to -20° (R2 = 0.838, RMSE = 0.360) and relatively good accuracy at 0° to -30° (R2 = 0.835, RMSE = 0.366). As it is possible to monitor plant N status over a wide range of angles using portable spectrometers, viewing angles of as much as 0° to -30° are common. Consequently, we developed a united model across angles of 0° to -30° to reduce the effects of viewing angle on LNC prediction in wheat. The proposed combined NDRE/FWBI parameter, designated the wide-angle-adaptability nitrogen index (WANI), is superior for estimating LNC in wheat on a regional scale in China and Canada.

Enhanced contrast ratio and viewing angle of polymer-stabilized liquid crystal via refractive index matching between liquid crystal and polymer network.

PubMed

Lee, Ji-Hoon; Lee, Jung Jin; Lim, Young Jin; Kundu, Sudarshan; Kang, Shin-Woong; Lee, Seung Hee

2013-11-04

Long standing electro-optic problems of a polymer-dispersed liquid crystal (PDLC) such as low contrast ratio and transmittances decrease in oblique viewing angle have been challenged with a mixture of dual frequency liquid crystal (DFLC) and reactive mesogen (RM). The DFLC and RM molecules were vertically aligned and then photo-polymerized using a UV light. At scattering state under 50 kHz electric field, DFLC was switched to planar state, giving greater extraordinary refractive index than the normal PDLC cell. Consequently, the scattering intensity and the contrast ratio were increased compared to the conventional PDLC cell. At transparent state under 1 kHz electric field, the extraordinary refractive index of DFLC was simultaneously matched with the refractive index of vertically aligned RM so that the light scattering in oblique viewing angles was minimized, giving rise to high transmittance in all viewing angles.

Simulated response of a multispectral scanner over wheat as a function of wavelength and view/illumination direction

NASA Technical Reports Server (NTRS)

Bauer, M. E. (Principal Investigator); Vanderbilt, V. C.; Robinson, B. F.; Biehl, L. L.; Vanderbilt, A. S.

1981-01-01

The reflectance response with view angle of wheat, was analyzed. The analyses, which assumes there are no atmospheric effects, and otherwise simulates the response of a multispectral scanner, is based upon spectra taken continuously in wavelength from 0.45 to 2.4 micrometers at more than 1200 view/illumination directions using an Exotech model 20C spectra radiometer. Data were acquired six meters above four wheat canopies, each at a different growth stage. The analysis shows that the canopy reflective response is a pronounced function of illumination angle, scanner view angle and wavelength. The variation is greater at low solar elevations compared to high solar elevations.

Reflections on current and future applications of multiangle imaging to aerosol and cloud remote sensing

NASA Astrophysics Data System (ADS)

Diner, David

2010-05-01

The Multi-angle Imaging SpectroRadiometer (MISR) instrument has been collecting global Earth data from NASA's Terra satellite since February 2000. With its 9 along-track view angles, 4 spectral bands, intrinsic spatial resolution of 275 m, and stable radiometric and geometric calibration, no instrument that combines MISR's attributes has previously flown in space, nor is there is a similar capability currently available on any other satellite platform. Multiangle imaging offers several tools for remote sensing of aerosol and cloud properties, including bidirectional reflectance and scattering measurements, stereoscopic pattern matching, time lapse sequencing, and potentially, optical tomography. Current data products from MISR employ several of these techniques. Observations of the intensity of scattered light as a function of view angle and wavelength provide accurate measures of aerosol optical depths (AOD) over land, including bright desert and urban source regions. Partitioning of AOD according to retrieved particle classification and incorporation of height information improves the relationship between AOD and surface PM2.5 (fine particulate matter, a regulated air pollutant), constituting an important step toward a satellite-based particulate pollution monitoring system. Stereoscopic cloud-top heights provide a unique metric for detecting interannual variability of clouds and exceptionally high quality and sensitivity for detection and height retrieval for low-level clouds. Using the several-minute time interval between camera views, MISR has enabled a pole-to-pole, height-resolved atmospheric wind measurement system. Stereo imagery also makes possible global measurement of the injection heights and advection speeds of smoke plumes, volcanic plumes, and dust clouds, for which a large database is now available. To build upon what has been learned during the first decade of MISR observations, we are evaluating algorithm updates that not only refine retrieval accuracies but also include enhancements (e.g., finer spatial resolution) that would have been computationally prohibitive just ten years ago. In addition, we are developing technological building blocks for future sensors that enable broader spectral coverage, wider swath, and incorporation of high-accuracy polarimetric imaging. Prototype cameras incorporating photoelastic modulators have been constructed. To fully capitalize on the rich information content of the current and next-generation of multiangle imagers, several algorithmic paradigms currently employed need to be re-examined, e.g., the use of aerosol look-up tables, neglect of 3-D effects, and binary partitioning of the atmosphere into "cloudy" or "clear" designations. Examples of progress in algorithm and technology developments geared toward advanced application of multiangle imaging to remote sensing of aerosols and clouds will be presented.

Normalization of multidirectional red and NIR reflectances with the SAVI

NASA Technical Reports Server (NTRS)

Huete, A. R.; Hua, G.; Qi, J.; Chehbouni, A.; Van Leeuwen, W. J. D.

1992-01-01

Directional reflectance measurements were made over a semi-desert gramma grassland at various times of the growing season. View angle measurements from +40 to -40 degrees were made at various solar zenith angles and soil moisture conditions. The sensitivity of the Normalized Difference Vegetation Index (NDVI) and the Soil Adjusted Vegetation Index (SAVI) to bidirectional measurements was assessed for purposes of improving remote temporal monitoring of vegetation dynamics. The SAVI view angle response was found to be symmetric about nadir while the NDVI response was strongly anisotropic. This enabled the view angle behavior of the SAVI to be normalized with a cosine function. In contrast to the NDVI, the SAVI was able to minimize soil moisture and shadow influences for all measurement conditions.

Effects of changing canopy directional reflectance on feature selection

NASA Technical Reports Server (NTRS)

Smith, J. A.; Oliver, R. E.; Kilpela, O. E.

1973-01-01

The use of a Monte Carlo model for generating sample directional reflectance data for two simplified target canopies at two different solar positions is reported. Successive iterations through the model permit the calculation of a mean vector and covariance matrix for canopy reflectance for varied sensor view angles. These data may then be used to calculate the divergence between the target distributions for various wavelength combinations and for these view angles. Results of a feature selection analysis indicate that different sets of wavelengths are optimum for target discrimination depending on sensor view angle and that the targets may be more easily discriminated for some scan angles than others. The time-varying behavior of these results is also pointed out.

Expansion of the visual angle of a car rear-view image via an image mosaic algorithm

NASA Astrophysics Data System (ADS)

Wu, Zhuangwen; Zhu, Liangrong; Sun, Xincheng

2015-05-01

The rear-view image system is one of the active safety devices in cars and is widely applied in all types of vehicles and traffic safety areas. However, studies made by both domestic and foreign researchers were based on a single image capture device while reversing, so a blind area still remained to drivers. Even if multiple cameras were used to expand the visual angle of the car's rear-view image in some studies, the blind area remained because different source images were not mosaicked together. To acquire an expanded visual angle of a car rear-view image, two charge-coupled device cameras with optical axes angled at 30 deg were mounted below the left and right fenders of a car in three light conditions-sunny outdoors, cloudy outdoors, and an underground garage-to capture rear-view heterologous images of the car. Then these rear-view heterologous images were rapidly registered through the scale invariant feature transform algorithm. Combined with the random sample consensus algorithm, the two heterologous images were finally mosaicked using the linear weighted gradated in-and-out fusion algorithm, and a seamless and visual-angle-expanded rear-view image was acquired. The four-index test results showed that the algorithms can mosaic rear-view images well in the underground garage condition, where the average rate of correct matching was the lowest among the three conditions. The rear-view image mosaic algorithm presented had the best information preservation, the shortest computation time and the most complete preservation of the image detail features compared to the mean value method (MVM) and segmental fusion method (SFM), and it was also able to perform better in real time and provided more comprehensive image details than MVM and SFM. In addition, it had the most complete image preservation from source images among the three algorithms. The method introduced by this paper provided the basis for researching the expansion of the visual angle of a car rear-view image in all-weather conditions.

Bidirectional Reflectance Functions for Application to Earth Radiation Budget Studies

NASA Technical Reports Server (NTRS)

Manalo-Smith, N.; Tiwari, S. N.; Smith, G. L.

1997-01-01

Reflected solar radiative fluxes emerging for the Earth's top of the atmosphere are inferred from satellite broadband radiance measurements by applying bidirectional reflectance functions (BDRFs) to account for the anisotropy of the radiation field. BDRF's are dependent upon the viewing geometry (i.e. solar zenith angle, view zenith angle, and relative azimuth angle), the amount and type of cloud cover, the condition of the intervening atmosphere, and the reflectance characteristics of the underlying surface. A set of operational Earth Radiation Budget Experiment (ERBE) BDRFs is available which was developed from the Nimbus 7 ERB (Earth Radiation Budget) scanner data for a three-angle grid system, An improved set of bidirectional reflectance is required for mission planning and data analysis of future earth radiation budget instruments, such as the Clouds and Earth's Radiant Energy System (CERES), and for the enhancement of existing radiation budget data products. This study presents an analytic expression for BDRFs formulated by applying a fit to the ERBE operational model tabulations. A set of model coefficients applicable to any viewing condition is computed for an overcast and a clear sky scene over four geographical surface types: ocean, land, snow, and desert, and partly cloudy scenes over ocean and land. The models are smooth in terms of the directional angles and adhere to the principle of reciprocity, i.e., they are invariant with respect to the interchange of the incoming and outgoing directional angles. The analytic BDRFs and the radiance standard deviations are compared with the operational ERBE models and validated with ERBE data. The clear ocean model is validated with Dlhopolsky's clear ocean model. Dlhopolsky developed a BDRF of higher angular resolution for clear sky ocean from ERBE radiances. Additionally, the effectiveness of the models accounting for anisotropy for various viewing directions is tested with the ERBE along tract data. An area viewed from nadir and from the side give two different radiance measurements but should yield the same flux when converted by the BDRF. The analytic BDRFs are in very good qualitative agreement with the ERBE models. The overcast scenes exhibit constant retrieved albedo over viewing zenith angles for solar zenith angles less than 60 degrees. The clear ocean model does not produce constant retrieved albedo over viewing zenith angles but gives an improvement over the ERBE operational clear sky ocean BDRF.

THE VIEWING ANGLES OF BROAD ABSORPTION LINE VERSUS UNABSORBED QUASARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.

2012-06-10

It was recently shown that there is a significant difference in the radio spectral index distributions of broad absorption line (BAL) quasars and unabsorbed quasars, with an overabundance of BAL quasars with steeper radio spectra. This result suggests that source orientation does play into the presence or absence of BAL features. In this paper, we provide more quantitative analysis of this result based on Monte Carlo simulations. While the relationship between viewing angle and spectral index does indeed contain a lot of scatter, the spectral index distributions are different enough to overcome that intrinsic variation. Utilizing two different models ofmore » the relationship between spectral index and viewing angle, the simulations indicate that the difference in spectral index distributions can be explained by allowing BAL quasar viewing angles to extend about 10 Degree-Sign farther from the radio jet axis than non-BAL sources, though both can be seen at small angles. These results show that orientation cannot be the only factor determining whether BAL features are present, but it does play a role.« less

A wide field-of-view microscope based on holographic focus grid

NASA Astrophysics Data System (ADS)

Wu, Jigang; Cui, Xiquan; Zheng, Guoan; Lee, Lap Man; Yang, Changhuei

2010-02-01

We have developed a novel microscope technique that can achieve wide field-of-view (FOV) imaging and yet possess resolution that is comparable to conventional microscope. The principle of wide FOV microscope system breaks the link between resolution and FOV magnitude of traditional microscopes. Furthermore, by eliminating bulky optical elements from its design and utilizing holographic optical elements, the wide FOV microscope system is more cost-effective. In our system, a hologram was made to focus incoming collimated beam into a focus grid. The sample is put in the focal plane and the transmissions of the focuses are detected by an imaging sensor. By scanning the incident angle of the incoming beam, the focus grid will scan across the sample and the time-varying transmission can be detected. We can then reconstruct the transmission image of the sample. The resolution of microscopic image is limited by the size of the focus formed by the hologram. The scanning area of each focus spot is determined by the separation of the focus spots and can be made small for fast imaging speed. We have fabricated a prototype system with a 2.4-mm FOV and 1-μm resolution. The prototype system was used to image onion skin cells for a demonstration. The preliminary experiments prove the feasibility of the wide FOV microscope technique, and the possibility of a wider FOV system with better resolution.

4. Elevation view of Bunker 104 with ultrawide angle lens ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Elevation view of Bunker 104 with ultrawide angle lens shows about 70 percent of east facade including entire south end with steps and doors. View shows slope of south end and vegetation growing atop building. See also photo WA-203-C-3. - Puget Sound Naval Shipyard, Munitions Storage Bunker, Naval Ammunitions Depot, South of Campbell Trail, Bremerton, Kitsap County, WA

Young People and Physical Activity: A Systematic Review Matching Their Views to Effective Interventions

ERIC Educational Resources Information Center

Rees, Rebecca; Kavanagh, J.; Harden, A.; Shepherd, J.; Brunton, G.; Oliver, S.; Oakley, A.

2006-01-01

A systematic review was conducted to examine the barriers to, and facilitators of, physical activity among young people (11-16 years). The review focused on the wider determinants of health, examining community- and society-level interventions. Four trials and 16 studies of young people's views were included. Evidence for the effectiveness of the…

Dyslexia: A Wider View. The Contribution of an Ecological Paradigm to Current Issues.

ERIC Educational Resources Information Center

Poole, Jennifer

2003-01-01

Dyslexia issues such as its existence, definition, and medical versus educational construction have been framed by the scientific paradigm. Reframing using an ecological perspective allows assessment focused on whole-school approaches and sociocultural factors. It also enables the use of predictive research and a view of dyslexia as more than a…

Geographical Locational Knowledge as an Indicator of Children's Views of the World: Research from Sweden and Australia

ERIC Educational Resources Information Center

Reynolds, Ruth; Vinterek, Monika

2016-01-01

Children's locational knowledge is often used to clarify underlying conceptual understandings of the world in which they live. Although there has been some exploration of how European children view their world there is little recent research on Scandinavian children's knowledge and associated perceptions of the wider world, or about Australian…

You Have to Be Prepared to Drink: Students' Views about Reducing Excessive Alcohol Consumption at University

ERIC Educational Resources Information Center

Davies, Emma L.; Law, Cara; Hennelly, Sarah E.

2018-01-01

Purpose: Many existing interventions to reduce excessive drinking in university students attempt to target individual cognitions, which ignore the wider contextual features that drive excessive drinking and mark this as an important aspect of university life. The purpose of this paper is to explore students' views about preventing excessive…

School Autonomy and Government Control: School Leaders' Views on a Changing Policy Landscape in England

ERIC Educational Resources Information Center

Higham, Rob; Earley, Peter

2013-01-01

The Conservative-Liberal Democrat Coalition government elected in 2010 has argued contemporary reform will increase the autonomy of schools in England. Given the complexities that exist, however, in the balance between autonomy and control, we explore how school leaders view autonomy as it exists within the wider policy framework. The article…

What is MISR? MISR Instrument? MISR Project?

Atmospheric Science Data Center

2014-12-08

... to improve our understanding of the Earth's environment and climate. Viewing the sunlit Earth simultaneously at nine widely-spaced angles, ... types of atmospheric particles and clouds on climate. The change in reflection at different view angles affords the means to distinguish ...

Array Of Sensors Measures Broadband Radiation

NASA Technical Reports Server (NTRS)

Hoffman, James W.; Grush, Ronald G.

1994-01-01

Multiple broadband radiation sensors aimed at various portions of total field of view. All sensors mounted in supporting frame, serving as common heat sink and temperature reference. Each sensor includes heater winding and differential-temperature-sensing bridge circuit. Power in heater winding adjusted repeatedly in effort to balance bridge circuit. Intended to be used aboard satellite in orbit around Earth to measure total radiation emitted, at various viewing angles, by mosaic of "footprint" areas (each defined by its viewing angle) on surface of Earth. Modified versions of array useful for angle-resolved measurements of broadband radiation in laboratory and field settings on Earth.

An Innovate Robotic Endoscope Guidance System for Transnasal Sinus and Skull Base Surgery: Proof of Concept.

PubMed

Friedrich, D T; Sommer, F; Scheithauer, M O; Greve, J; Hoffmann, T K; Schuler, P J

2017-12-01

Objective  Advanced transnasal sinus and skull base surgery remains a challenging discipline for head and neck surgeons. Restricted access and space for instrumentation can impede advanced interventions. Thus, we present the combination of an innovative robotic endoscope guidance system and a specific endoscope with adjustable viewing angle to facilitate transnasal surgery in a human cadaver model. Materials and Methods  The applicability of the robotic endoscope guidance system with custom foot pedal controller was tested for advanced transnasal surgery on a fresh frozen human cadaver head. Visualization was enabled using a commercially available endoscope with adjustable viewing angle (15-90 degrees). Results  Visualization and instrumentation of all paranasal sinuses, including the anterior and middle skull base, were feasible with the presented setup. Controlling the robotic endoscope guidance system was effectively precise, and the adjustable endoscope lens extended the view in the surgical field without the common change of fixed viewing angle endoscopes. Conclusion  The combination of a robotic endoscope guidance system and an advanced endoscope with adjustable viewing angle enables bimanual surgery in transnasal interventions of the paranasal sinuses and the anterior skull base in a human cadaver model. The adjustable lens allows for the abandonment of fixed-angle endoscopes, saving time and resources, without reducing the quality of imaging.

Visual Image Sensor Organ Replacement

NASA Technical Reports Server (NTRS)

Maluf, David A.

2014-01-01

This innovation is a system that augments human vision through a technique called "Sensing Super-position" using a Visual Instrument Sensory Organ Replacement (VISOR) device. The VISOR device translates visual and other sensors (i.e., thermal) into sounds to enable very difficult sensing tasks. Three-dimensional spatial brightness and multi-spectral maps of a sensed image are processed using real-time image processing techniques (e.g. histogram normalization) and transformed into a two-dimensional map of an audio signal as a function of frequency and time. Because the human hearing system is capable of learning to process and interpret extremely complicated and rapidly changing auditory patterns, the translation of images into sounds reduces the risk of accidentally filtering out important clues. The VISOR device was developed to augment the current state-of-the-art head-mounted (helmet) display systems. It provides the ability to sense beyond the human visible light range, to increase human sensing resolution, to use wider angle visual perception, and to improve the ability to sense distances. It also allows compensation for movement by the human or changes in the scene being viewed.

Simple, monolithic optical element for forward-viewing spectrally encoded endoscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Do, Dukho; Kang, Dongkyun; Ikuta, Mitsuhiro; Tearney, Guillermo J.

2016-03-01

Spectrally encoded endoscopy (SEE) is a miniature endoscopic technology that can acquire images of internal organs through a hair-thin probe. While most previously described SEE probes have been side viewing, forward-view (FV)-SEE is advantageous in certain clinical applications as it provides more natural navigation of the probe and has the potential to provide a wider field of view. Prior implementations of FV-SEE used multiple optical elements that increase fabrication complexity and may diminish the robustness of the device. In this paper, we present a new design that uses a monolithic optical element to realize FV-SEE imaging. The optical element is specially designed spacer, fabricated from a 500-μm-glass rod that has a mirror surface on one side and a grating stamped on its distal end. The mirror surface is used to change the incident angle on the grating to diffract the shortest wavelength of the spectrum so that it is parallel to the optical axis. Rotating the SEE optics creates a circular FV-SEE image. Custom-designed software processes FV-SEE images into circular images, which are displayed in real-time. In order to demonstrate this new design, we have constructed the FV-SEE optical element using a 1379 lines/mm diffraction grating. When illuminated with a source with a spectral bandwidth of 420-820 nm, the FV-SEE optical element provides 678 resolvable points per line. The imaging performance of the FV-SEE device was tested by imaging a USAF resolution target. SEE images showed that this new approach generates high quality images in the forward field with a field of view of 58°. Results from this preliminary study demonstrate that we can realize FV-SEE imaging with simple, monolithic, miniature optical element. The characteristics of this FV-SEE configuration will facilitate the development of robust miniature endoscopes for a variety of medical imaging applications.

1. VARIABLEANGLE LAUNCHER CAMERA CAR, VIEW OF CAMERA CAR AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VARIABLE-ANGLE LAUNCHER CAMERA CAR, VIEW OF CAMERA CAR AND TRACK WITH CAMERA STATION ABOVE LOOKING NORTH TAKEN FROM RESERVOIR. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

The ethics of drug development and promotion: the need for a wider view.

PubMed

Brody, Howard

2012-11-01

Ethical issues at the interface between the medical profession and the pharmaceutical industry have generally been approached from the vantage point of medical professionalism, with a focus on conflict of interest as the key ethical concern. Although conflicts of interest remain important, other ethical issues may be obscured unless a wider perspective is adopted. Besides medical professionalism, the ethics of the clinical therapeutic relationship, ethics of public health, and business ethics all provide additional insights.

79. VIEW OF VAL FIRING RANGE LOOKING SOUTHWEST SHOWING LAUNCHER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

79. VIEW OF VAL FIRING RANGE LOOKING SOUTHWEST SHOWING LAUNCHER BRIDGE, BARGES, SONAR BUOY RANGE AND MORRIS DAM IN BACKGROUND, June 10, 1948. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Mobile Robot Localization by Remote Viewing of a Colored Cylinder

NASA Technical Reports Server (NTRS)

Volpe, R.; Litwin, T.; Matthies, L.

1995-01-01

A system was developed for the Mars Pathfinder rover in which the rover checks its position by viewing the angle back to a colored cylinder with different colors for different angles. The rover determines distance by the apparent size of the cylinder.

New developments of a knowledge based system (VEG) for inferring vegetation characteristics

NASA Technical Reports Server (NTRS)

Kimes, D. S.; Harrison, P. A.; Harrison, P. R.

1992-01-01

An extraction technique for inferring physical and biological surface properties of vegetation using nadir and/or directional reflectance data as input has been developed. A knowledge-based system (VEG) accepts spectral data of an unknown target as input, determines the best strategy for inferring the desired vegetation characteristic, applies the strategy to the target data, and provides a rigorous estimate of the accuracy of the inference. Progress in developing the system is presented. VEG combines methods from remote sensing and artificial intelligence, and integrates input spectral measurements with diverse knowledge bases. VEG has been developed to (1) infer spectral hemispherical reflectance from any combination of nadir and/or off-nadir view angles; (2) test and develop new extraction techniques on an internal spectral database; (3) browse, plot, or analyze directional reflectance data in the system's spectral database; (4) discriminate between user-defined vegetation classes using spectral and directional reflectance relationships; and (5) infer unknown view angles from known view angles (known as view angle extension).

[Influence of surface roughness on degree of polarization of biotite plagioclase gneiss varying with viewing angle].

PubMed

Xiang, Yun; Yan, Lei; Zhao, Yun-sheng; Gou, Zhi-yang; Chen, Wei

2011-12-01

Polarized reflectance is influenced by such factors as its physical and chemical properties, the viewing geometry composed of light incident zenith, viewing zenith and viewing azimuth relative to light incidence, surface roughness and texture, surface density, detection wavelengths, polarization phase angle and so on. In the present paper, the influence of surface roughness on the degree of polarization (DOP) of biotite plagioclase gneiss varying with viewing angle was inquired and analyzed quantitatively. The polarized spectra were measured by ASD FS3 spectrometer on the goniometer located in Northeast Normal University. When the incident zenith angle was fixed at 50 degrees, it was showed that on the rock surfaces with different roughness, in the specular reflection direction, the DOP spectrum within 350-2500 nm increased to the highest value first, and then began to decline varying with viewing zenith angle from 0 degree to 80 degrees. The characterized band (520 +/- 10) nm was picked out for further analysis. The correlation analysis between the peak DOP value of zenith and surface roughness showed that they are in a power function relationship, with the regression equation: y = 0.604x(-0.297), R2 = 0.985 4. The correlation model of the angle where the peak is in and the surface roughness is y = 3.4194x + 51.584, y < 90 degrees , R2 = 0.8177. With the detecting azimuth farther away from 180 degrees azimuth where the maximum DOP exists, the DOP lowers gradually and tends to 0. In the detection azimuth 180 dgrees , the correlation analysis between the peak values of DOP on the (520 =/- 10) nm band for five rocks and their surface roughness indicates a power function, with the regression equation being y = 0.5822x(-0.333), R2 = 0.9843. F tests of the above regression models indicate that the peak value and its corresponding viewing angle correlate much with surface roughness. The study provides a theoretical base for polarization remote sensing, and impels the rock and city architecture discrimination and minerals mapping.

Anthropological Approaches to the Study of Housing Areas: Lessons from Oaxaca City, Mexico.

ERIC Educational Resources Information Center

Murphy, Arthur D.

The anthropological study of the city's role in the evolution of human systems requires the use of both macro and micro levels of analysis. From the macro perspective, the city is viewed as part of a wider complex society, while from the micro point of view, the city provides the context for understanding specific human institutions or processes…

The Legal Limitations on Defending the National Information Infrastructure Against a Cyber Attack

DTIC Science & Technology

1999-05-27

has a wider significance .... Kelsen has asserted that ’use of force’ in Article 2, paragraph 4, of the Charter includes both the use of arms and a...or United Nations practice that it bears the meaning suggested by Kelsen . Indeed, in view of the predominant view of aggression and the use of force

Pupils' Views on an ICT-Based Learning Environment in Health Learning

ERIC Educational Resources Information Center

Räihä, Teija; Tossavainen, Kerttu; Enkenberg, Jorma; Turunen, Hannele

2014-01-01

This paper presents a study that examined pupils' views on an ICT-based learning environment in health learning. The study was a part of the wider European Network of Health Promoting Schools programme (ENHPS; since 2008, Schools for Health in Europe, SHE) in Finland, and particularly its sub-project, From Puijo to the World with Health Lunch,…

13. OBLIQUE VIEW OF UPPER ORE BIN, LOOKING WEST NORTHWEST. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. OBLIQUE VIEW OF UPPER ORE BIN, LOOKING WEST NORTHWEST. THIS ORE BIN WAS ADDED IN THE LATE 1930'S. IT IS TRAPAZOIDAL IN SHAPE, WIDER AT THE REAR THAN THE FRONT, AND DIVIDED INTO THREE BINS, EACH WITH ITS OWN CONTROL DOOR (SEE CA-290-15). - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

Sensitivity of MODIS 2.1-(micrometers) Channel for Off-Nadir View Angles for Use in Remote Sensing of Aerosol

NASA Technical Reports Server (NTRS)

Gatebe, C. K.; King, M. D.; Tsay, S.-C.; Ji, Q.; Arnold, T.

2000-01-01

In this sensitivity study, we examined the ratio technique, the official method for remote sensing of aerosols over land from Moderate Resolution Imaging Spectroradiometer (MODIS) DATA, for view angles from nadir to 65 deg. off-nadir using Cloud Absorption Radiometer (CAR) data collected during the Smoke, Clouds, and Radiation-Brazil (SCAR-B) experiment conducted in 1995. For the data analyzed and for the view angles tested, results seem to suggest that the reflectance (rho)0.47 and (rho)0.67 are predictable from (rho)2.1 using: (rho)0.47 = (rho)2.1/6, which is a slight modification and (rho)0.67 = (rho)2.1/2. These results hold for target viewed from backscattered direction, but not for the forward direction.

Sliding mode control based impact angle control guidance considering the seeker׳s field-of-view constraint.

PubMed

Wang, Xingliang; Zhang, Youan; Wu, Huali

2016-03-01

The problem of impact angle control guidance for a field-of-view constrained missile against non-maneuvering or maneuvering targets is solved by using the sliding mode control theory. The existing impact angle control guidance laws with field-of-view constraint are only applicable against stationary targets and most of them suffer abrupt-jumping of guidance command due to the application of additional guidance mode switching logic. In this paper, the field-of-view constraint is handled without using any additional switching logic. In particular, a novel time-varying sliding surface is first designed to achieve zero miss distance and zero impact angle error without violating the field-of-view constraint during the sliding mode phase. Then a control integral barrier Lyapunov function is used to design the reaching law so that the sliding mode can be reached within finite time and the field-of-view constraint is not violated during the reaching phase as well. A nonlinear extended state observer is constructed to estimate the disturbance caused by unknown target maneuver, and the undesirable chattering is alleviated effectively by using the estimation as a compensation item in the guidance law. The performance of the proposed guidance law is illustrated with simulations. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

74. DETAIL VIEW OF INSIDE THE LAUNCHING BRIDGE LOOKING SOUTHWEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

74. DETAIL VIEW OF INSIDE THE LAUNCHING BRIDGE LOOKING SOUTHWEST SHOWING ADJUSTABLE STAIRS ON THE LEFT AND LAUNCHING TUBE ON THE RIGHT, Date unknown, circa 1948. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Prediction beyond the borders: ERP indices of boundary extension-related error.

PubMed

Czigler, István; Intraub, Helene; Stefanics, Gábor

2013-01-01

Boundary extension (BE) is a rapidly occurring memory error in which participants incorrectly remember having seen beyond the boundaries of a view. However, behavioral data has provided no insight into how quickly after the onset of a test picture the effect is detected. To determine the time course of BE from neural responses we conducted a BE experiment while recording EEG. We exploited a diagnostic response asymmetry to mismatched views (a closer and wider view of the same scene) in which the same pair of views is rated as more similar when the closer item is shown first than vice versa. On each trial, a closer or wider view was presented for 250 ms followed by a 250-ms mask and either the identical view or a mismatched view. Boundary ratings replicated the typical asymmetry. We found a similar asymmetry in ERP responses in the 265-285 ms interval where the second member of the close-then-wide pairs evoked less negative responses at left parieto-temporal sites compared to the wide-then-close condition. We also found diagnostic ERP effects in the 500-560 ms range, where ERPs to wide-then-close pairs were more positive at centro-parietal sites than in the other three conditions, which is thought to be related to participants' confidence in their perceptual decision. The ERP effect in the 265-285 ms range suggests the falsely remembered region beyond the view-boundaries of S1 is rapidly available and impacts assessment of the test picture within the first 265 ms of viewing, suggesting that extrapolated scene structure may be computed rapidly enough to play a role in the integration of successive views during visual scanning.

A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

NASA Astrophysics Data System (ADS)

Yagi, N.; Ohta, N.; Matsuo, T.; Tanaka, T.; Terada, Y.; Kamasaka, H.; Kometani, T.

2010-10-01

The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6μm at BL40XU and 50μm at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

Optimal design of wide-view-angle waveplate used for polarimetric diagnosis of lithography system

NASA Astrophysics Data System (ADS)

Gu, Honggang; Jiang, Hao; Zhang, Chuanwei; Chen, Xiuguo; Liu, Shiyuan

2016-03-01

The diagnosis and control of the polarization aberrations is one of the main concerns in a hyper numerical aperture (NA) lithography system. Waveplates are basic and indispensable optical components in the polarimetric diagnosis tools for the immersion lithography system. The retardance of a birefringent waveplate is highly sensitive to the incident angle of the light, which makes the conventional waveplate not suitable to be applied in the polarimetric diagnosis for the immersion lithography system with a hyper NA. In this paper, we propose a method for the optimal design of a wideview- angle waveplate by combining two positive waveplates made from magnesium fluoride (MgF2) and two negative waveplates made from sapphire using the simulated annealing algorithm. Theoretical derivations and numerical simulations are performed and the results demonstrate that the maximum variation in the retardance of the optimally designed wide-view-angle waveplate is less than +/- 0.35° for a wide-view-angle range of +/- 20°.

View-angle-dependent AIRS Cloudiness and Radiance Variance: Analysis and Interpretation

NASA Technical Reports Server (NTRS)

Gong, Jie; Wu, Dong L.

2013-01-01

Upper tropospheric clouds play an important role in the global energy budget and hydrological cycle. Significant view-angle asymmetry has been observed in upper-level tropical clouds derived from eight years of Atmospheric Infrared Sounder (AIRS) 15 um radiances. Here, we find that the asymmetry also exists in the extra-tropics. It is larger during day than that during night, more prominent near elevated terrain, and closely associated with deep convection and wind shear. The cloud radiance variance, a proxy for cloud inhomogeneity, has consistent characteristics of the asymmetry to those in the AIRS cloudiness. The leading causes of the view-dependent cloudiness asymmetry are the local time difference and small-scale organized cloud structures. The local time difference (1-1.5 hr) of upper-level (UL) clouds between two AIRS outermost views can create parts of the observed asymmetry. On the other hand, small-scale tilted and banded structures of the UL clouds can induce about half of the observed view-angle dependent differences in the AIRS cloud radiances and their variances. This estimate is inferred from analogous study using Microwave Humidity Sounder (MHS) radiances observed during the period of time when there were simultaneous measurements at two different view-angles from NOAA-18 and -19 satellites. The existence of tilted cloud structures and asymmetric 15 um and 6.7 um cloud radiances implies that cloud statistics would be view-angle dependent, and should be taken into account in radiative transfer calculations, measurement uncertainty evaluations and cloud climatology investigations. In addition, the momentum forcing in the upper troposphere from tilted clouds is also likely asymmetric, which can affect atmospheric circulation anisotropically.

The big picture: effects of surround on immersion and size perception.

PubMed

Baranowski, Andreas M; Hecht, Heiko

2014-01-01

Despite the fear of the entertainment industry that illegal downloads of films might ruin their business, going to the movies continues to be a popular leisure activity. One reason why people prefer to watch movies in cinemas may be the surround of the movie screen or its physically huge size. To disentangle the factors that might contribute to the size impression, we tested several measures of subjective size and immersion in different viewing environments. For this purpose we built a model cinema that provided visual angle information comparable with that of a real cinema. Subjects watched identical movie clips in a real cinema, a model cinema, and on a display monitor in isolation. Whereas the isolated display monitor was inferior, the addition of a contextual model improved the viewing immersion to the extent that it was comparable with the movie theater experience, provided the viewing angle remained the same. In a further study we built an identical but even smaller model cinema to unconfound visual angle and viewing distance. Both model cinemas produced similar results. There was a trend for the larger screen to be more immersive; however, viewing angle did not play a role in how the movie was evaluated.

22. VAL, VIEW OF PROJECTILE LOADING DECK LOOKING NORTHEAST TOWARD ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. VAL, VIEW OF PROJECTILE LOADING DECK LOOKING NORTHEAST TOWARD TOP OF CONCRETE 'A' FRAME STRUCTURE SHOWING DRIVE CABLES, DRIVE GEAR, BOTTOM OF CAMERA TOWER AND 'CROWS NEST' CONTROL ROOM. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Wide angle view of the Flight control room of Mission control center

NASA Image and Video Library

1984-10-06

Wide angle view of the flight control room (FCR) of the Mission Control Center (MCC). Some of the STS 41-G crew can be seen on a large screen at the front of the MCC along with a map tracking the progress of the orbiter.

Wide angle view of Mission Control Center during Apollo 14 transmission

NASA Image and Video Library

1971-01-31

S71-17122 (31 Jan. 1971) --- A wide angle overall view of the Mission Operations Control Room (MOCR) in the Mission Control Center at the Manned spacecraft Center. This view was photographed during the first color television transmission from the Apollo 14 Command Module. Projected on the large screen at the right front of the MOCR is a view of the Apollo 14 Lunar Module, still attached to the Saturn IVB stage. The Command and Service Modules were approaching the LM/S-IVB during transposition and docking maneuvers.

Optimal directional view angles for remote-sensing missions

NASA Technical Reports Server (NTRS)

Kimes, D. S.; Holben, B. N.; Tucker, C. J.; Newcomb, W. W.

1984-01-01

The present investigation is concerned with the directional, off-nadir viewing of terrestrial scenes using remote-sensing systems from aircraft and satellite platforms, taking into account advantages of such an approach over strictly nadir viewing systems. Directional reflectance data collected for bare soil and several different vegetation canopies in NOAA-7 AVHRR bands 1 and 2 were analyzed. Optimum view angles were recommended for two strategies. The first strategy views the utility of off-nadir measurements as extending spatial and temporal coverage of the target area. The second strategy views the utility of off-nadir measurements as providing additional information about the physical characteristics of the target. Conclusions regarding the two strategies are discussed.

Lunar Sodium and Potassium Exosphere in May 2014

NASA Astrophysics Data System (ADS)

Oliversen, R. J.; Kuruppuaratchi, D. C. P.; Mierkiewicz, E. J.; Derr, N. J.; Rosborough, S.; Gallant, M. A.; Roesler, F. L.

2015-12-01

We apply high resolution spectroscopy to investigate the lunar exosphere by measuring sodium and potassium spectral line profiles to determine the variations in exospheric effective temperatures and velocities. Observations were made at the National Solar Observatory McMath-Pierce Telescope during May 2014. Data were collected over several nights, centered on full moon (May 14) and covering a waxing phase angle of 67° to a waning phase angle of 75°. We used a dual-etalon Fabry-Perot spectrometer with a resolving power of 184,000 (1.63 km s-1) to measure the line widths and radial velocity shifts of the sodium D2 (5889.951 Å) and potassium D1 (7698.965 Å) emission lines. The field of view was 3 arcmin (~330 km) and positioned at several locations, each centered at 1.5 arcmin (~165 km) off the East and West sunlit limbs. The deconvolved line widths indicate significant differences between the sodium and potassium temperatures. The sodium line widths were mostly symmetric as a function of phase for both the waxing and waning phases. At phase angles > 40º (outside of the magnetotail) the full width half maximum (FWHM) line widths are 1.5 - 2.0 km s-1 or ~1500 K for FWHM = 1.75 km s-1. Inside the magnetotail (phase angle < 40º) and near full moon (phase angle ~6°), the FWHM increased to ~4 km s-1. The implied line width temperature is 8000 K, although some of the observed line width may be due to a dispersion in velocities from many contribution along the extended sodium tail. Unlike sodium, the potassium line widths are wider by 50% during the waxing phase compared to the waning phase at phases > 40º. The potassium temperatures pre-magnetotail passage are ~1000 K while the temperatures post-magnetotail passage are ~2000K. At phase angles < 40º, the potassium intensities decreased dramatically; on consecutive days, when the phase angle changed from 44º to 31º to 20º, the relative intensities dropped by 1.0:0.6:0.15. The potassium intensity in the East and West equatorial regions (latitude < 10º) were similar; however, the potassium intensity was brightest off the limb near Aristarchus (latitude ~24º), which was the crater we observed nearest the KREEP region. This work was partially supported by the NASA Planetary Astronomy programs, NNX11AE38G and NNX13AL30G.

A Different Description of Trauma: A Wider Systemic Perspective--A Personal Insight

ERIC Educational Resources Information Center

Healey, Arlene

2004-01-01

This special edition of Child Care in Practice provides a unique opportunity to reflect on the years since the signing of the Belfast Agreement in 1998 and the period leading up to this. This article offers my personal views based on my experience of working with families affected by the Troubles. As a family therapist I am trained to view matters…

Exploring Primary Children's Views and Experiences of the School Ground: The Case of a Greek School

ERIC Educational Resources Information Center

Christidou, Vasilia; Tsevreni, Irida; Epitropou, Maria; Kittas, Constantinos

2013-01-01

The present study explores the use of a conventional school ground of a primary school and its potential as a space for creative play and environmental learning. Children's play behavior and views of the school ground are explored, as well as their vision for its improvement. The research constitutes part of a wider school ground project and was…

Optimal angle of needle insertion for fluoroscopy-guided transforaminal epidural injection of L5.

PubMed

Ra, In-Hoo; Min, Woo-Kie

2015-06-01

Unlike other sites, there is difficulty in performing TFESI at the L5-S1 level because the iliac crest is an obstacle to needle placement. The objective of this study was to identify the optimal angle of fluoroscopy for insertion and advancement of a needle during L5 TEFSI. We conducted an observational study of patients undergoing fluoroscopy-guided L5 TFESI in the prone position. A total of 80 patients (40 men and 40 women) with radiating pain of lower limbs were enrolled. During TFESI, we measured the angle at which the L5 vertebral body forms a rectangular shape and compared men and women. Then, we measured area of safe triangle in tilting angle of fluoroscopy from 15° to 35° and compared men and women. The mean cephalocaudal angle, where the vertebral body takes the shape of a rectangle, was 11.0° in men and 13.9° in women (P = 0.007). In men, the triangular area was maximal at 18.3 mm² with an oblique view angle of 25°. In women, the area was maximal at 23.6 mm² with an oblique view angle of 30°. At an oblique view angle of 30° and 35°, the area was significantly greater in women (P < 0.05). When TFESI is performed at the L5 region in the prone position, placement of fluoroscopy at a cephalocaudal angle of 11.0° and an oblique angle of 25° in men and cephalocaudal angle of 13.9° and an oblique angle of 30° in women would be most reasonable. © 2014 World Institute of Pain.

Vertical viewing angle enhancement for the 360  degree integral-floating display using an anamorphic optic system.

PubMed

Erdenebat, Munkh-Uchral; Kwon, Ki-Chul; Yoo, Kwan-Hee; Baasantseren, Ganbat; Park, Jae-Hyeung; Kim, Eun-Soo; Kim, Nam

2014-04-15

We propose a 360 degree integral-floating display with an enhanced vertical viewing angle. The system projects two-dimensional elemental image arrays via a high-speed digital micromirror device projector and reconstructs them into 3D perspectives with a lens array. Double floating lenses relate initial 3D perspectives to the center of a vertically curved convex mirror. The anamorphic optic system tailors the initial 3D perspectives horizontally and vertically disperse light rays more widely. By the proposed method, the entire 3D image provides both monocular and binocular depth cues, a full-parallax demonstration with high-angular ray density and an enhanced vertical viewing angle.

Detection Angle Calibration of Pressure-Sensitive Paints

NASA Technical Reports Server (NTRS)

Bencic, Timothy J.

2000-01-01

Uses of the pressure-sensitive paint (PSP) techniques in areas other than external aerodynamics continue to expand. The NASA Glenn Research Center has become a leader in the application of the global technique to non-conventional aeropropulsion applications including turbomachinery testing. The use of the global PSP technique in turbomachinery applications often requires detection of the luminescent paint in confined areas. With the limited viewing usually available, highly oblique illumination and detection angles are common in the confined areas in these applications. This paper will describe the results of pressure, viewing and excitation angle dependence calibrations using three popular PSP formulations to get a better understanding of the errors associated with these non-traditional views.

Concept development for the ITER equatorial port visible∕infrared wide angle viewing system.

PubMed

Reichle, R; Beaumont, B; Boilson, D; Bouhamou, R; Direz, M-F; Encheva, A; Henderson, M; Huxford, R; Kazarian, F; Lamalle, Ph; Lisgo, S; Mitteau, R; Patel, K M; Pitcher, C S; Pitts, R A; Prakash, A; Raffray, R; Schunke, B; Snipes, J; Diaz, A Suarez; Udintsev, V S; Walker, C; Walsh, M

2012-10-01

The ITER equatorial port visible∕infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R&D topics are outlined.

The Interaction of Extremist Propaganda and Anger as Predictors of Violent Responses.

PubMed

Shortland, Neil; Nader, Elias; Imperillo, Nicholas; Ross, Kyrielle; Dmello, Jared

2017-12-01

In this study, and with a view to extending upon existing findings on the effects of general violent media on violent cognitions, we experimentally measured the relationship between exposure to extremist propaganda and violent cognitions. Our results countered our hypotheses and the wider findings of violent media and aggression that exposure to violent stimuli increases violent thoughts and that this effect is moderated by trait aggression. Specifically, this study found that participants with low and medium trait aggression became more pro-social after being exposed to extremist propaganda. We discuss these results with reference to theories of terror management and mortality salience, as well as the implications of these results for wider theories of the role of online extremist material in the wider "radicalization" process.

81. VIEW OF VAL LOOKING NORTH AS SEEN FROM THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

81. VIEW OF VAL LOOKING NORTH AS SEEN FROM THE RESERVOIR SHOWING TWO LAUNCHING TUBES ON THE LAUNCHER BRIDGE, Date unknown, circa 1952. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

63. VIEW LOOKING DOWN VAL LAUNCHING SLAB SHOWING DRIVE GEARS, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

63. VIEW LOOKING DOWN VAL LAUNCHING SLAB SHOWING DRIVE GEARS, CABLES, LAUNCHER RAILS, PROJECTILE CAR AND SUPPORT CARRIAGE, April 8, 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

View angle effects on relationships between leaf area index in wheat and vegetation indices

NASA Astrophysics Data System (ADS)

Chen, H.; Li, W.; Huang, W.; Niu, Z.

2016-12-01

The effects of plant types and view angles on the canopy-reflected spectrum can not be ignored in the estimation of leaf area index (LAI) using remote sensing vegetation indices. While vegetation indices derived from nadir-viewing remote sensors are insufficient in leaf area index (LAI) estimation because of its misinterpretation of structural characteristecs, vegetation indices derived from multi-angular remote sensors have potential to improve detection of LAI. However, view angle effects on relationships between these indices and LAI for low standing crops (i.e. wheat) has not been fully evaluated and thus limits them to applied for consistent and accurate monitoring of vegetation. View angles effects of two types of winter wheat (wheat 411, erectophile; and wheat 9507, planophile) on relationship between LAI and spectral reflectance are assessed and compared in this study. An evaluation is conducted with in-situ measurements of LAI and bidirectional reflectance in the principal plane from -60° (back-scattering direction ) ot 60° (forward scattering direction) in the growth cycle of winter wheat. A variety of vegetation indices (VIs) published are calculated by BRDF. Additionally, all combinations of the bands are used in order to calculate Normalized difference Spectral Indices (NDSI) and Simple Subtraction Indices (SSI). The performance of the above indices along with raw reflectance and reflectance derivatives on LAI estimation are examined based on a linearity comparison. The results will be helpful in further developing multi-angle remote sensing models for accurate LAI evaluation.

Development of a Model to Correct Multi-View Angle above Water Measurements for the Analysis of the Bidirectional Reflectance of Coral and Other Reef Substrates

NASA Astrophysics Data System (ADS)

Miller, I.; Forster, B. C.; Laffan, S. W.

2012-07-01

Spectral reflectance characteristics of substrates in a coral reef environment are often measured in the field by viewing a substrate at nadir. However, viewing a substrate from multiple angles would likely result in different spectral characteristics for most coral reef substrates and provide valuable information on structural properties. To understand the relationship between the morphology of a substrate and its spectral response it is necessary to correct the observed above-water radiance for the effects of atmosphere and water attenuation, at a number of view and azimuth angles. In this way the actual surface reflectance can be determined. This research examines the air-water surface interaction for two hypothetical atmospheric conditions (clear Rayleigh scattering and totally cloudcovered) and the global irradiance reaching the benthic surface. It accounts for both water scattering and absorption, with simplifications for shallow water conditions, as well as the additive effect of background reflectance being reflected at the water-air surface at angles greater than the critical refraction angle (~48°). A model was developed to correct measured above-water radiance along the refracted view angle for its decrease due to path attenuation and the "n squared law of radiance" and the additive surface reflectance. This allows bidirectional benthic surface reflectance and nadir-normalised reflectance to be determined. These theoretical models were adapted to incorporate above-water measures relative to a standard, diffuse, white reference panel. The derived spectral signatures of a number of coral and non-coral benthic surfaces compared well with other published results, and the signatures and nadir normalised reflectance of the corals and other benthic surface classes indicate good class separation.

Soybean canopy reflectance as a function of view and illumination geometry

NASA Technical Reports Server (NTRS)

Bauer, M. E. (Principal Investigator); Ranson, K. J.; Vanderbilt, V. C.; Biehl, L. L.; Robinson, B. F.

1982-01-01

The results of an experiment designed to characterize a soybean field by its reflectance at various view and illumination angles and by its physical and agronomic attributes are presented. Reflectances were calculated from measurements at four wavelength bands through eight view azimuth and seven view zenith directions for various solar zenith and azimuth angles during portions of three days. An ancillary data set consisting of the agronomic and physical characteristics of the soybean field is described. The results indicate that the distribution of reflectance from a soybean field is a function of the solar illumination and viewing geometry, wavelength and row direction, as well as the state of development of the canopy. Shadows between rows greatly affected the reflectance in the visible wavelength bands and to a lesser extent in the near infrared wavelengths. A model is proposed that describes the reflectance variation as a function of projected solar and projected viewing angles. The model appears to approximate the reflectance variations in the visible wavelength bands from a canopy with well defined row structure.

Novel high-performance scattering materials for use in energy-saving light fittings and skylights based on polymer pigmented with polymer

NASA Astrophysics Data System (ADS)

Smith, Geoffrey B.; Earp, Alan; Franklin, Jim B.; McCredie, Geoffrey

2001-11-01

Simple quantitative performance criteria are developed for translucent materials in terms of hemispherical visible transmittance, and angular spread of transmitted luminance using a half angle. Criteria are linked to applications in luminaires and skylights with emphasis on maximising visible throughput while minimising glare. These basic criteria are also extended to angle of incidence changes which are substantial. Example data is provided showing that acrylic pigmented with spherical polymer particles can have total hemispherical transmittance with weak thickness dependence, which is better than clear sheet, while the spread of transmitted light is quite thickness-sensitive and occurs over wider angles than inorganic pigments. This combination means significantly fewer lamps can achieve specified lux levels with low glare, and smaller skylights can provide higher, more uniform daylight illuminance.

Modified locking thread form for fastener

NASA Technical Reports Server (NTRS)

Roopnarine, (Inventor); Vranish, John D. (Inventor)

1998-01-01

A threaded fastener has a standard part with a standard thread form characterized by thread walls with a standard included angle, and a modified part complementary to the standard part having a modified thread form characterized by thread walls which are symmetrically inclined with a modified included angle that is different from the standard included angle of the standard part's thread walls, such that the threads of one part make pre-loaded edge contact with the thread walls of the other part. The thread form of the modified part can have an included angle that is greater, less, or compound as compared to the included angle of the standard part. The standard part may be a bolt and the modified part a nut, or vice versa. The modified thread form holds securely even under large vibrational forces, it permits bi-directional use of standard mating threads, is impervious to the build up of tolerances and can be manufactured with a wider range of tolerances without loss of functionality, and distributes loading stresses (per thread) in a manner that decreases the possibility of single thread failure.

Optics of wide-angle panoramic viewing system-assisted vitreous surgery.

PubMed

Chalam, Kakarla V; Shah, Vinay A

2004-01-01

The purpose of the article is to describe the optics of the contact wide-angle lens system with stereo-reinverter for vitreous surgery. A panoramic viewing system is made up of two components; an indirect ophthalmoscopy lens system for fundus image viewing, which is placed on the patient's cornea as a contact lens, and a separate removable prism system for reinversion of the image mounted on the microscope above the zooming system. The system provides a 104 degrees field of view in a phakic emmetropic eye with minification, which can be magnified by the operating microscope. It permits a binocular stereoptic view even through a small pupil (3 mm) or larger. In an air-filled phakic eye, field of view increases to approximately 130 degrees. The obtained image of the patient's fundus is reinverted to form true, erect, stereoscopic image by the reinversion system. In conclusion, this system permits wide-angle panoramic view of the surgical field. The contact lens neutralizes the optical irregularities of the corneal surface and allows improved visualization in eyes with irregular astigmatism induced by corneal scars. Excellent visualization is achieved in complex clinical situations such as miotic pupils, lenticular opacities, and in air-filled phakic eyes.

Endoscopic pituitary surgery.

PubMed

Cappabianca, Paolo; Cavallo, Luigi Maria; de Divitiis, Oreste; Solari, Domenico; Esposito, Felice; Colao, Annamaria

2008-01-01

Pituitary surgery is a continuous evolving speciality of the neurosurgeons' armamentarium, which requires precise anatomical knowledge, technical skills and integrated appreciation of the pituitary pathophysiology. What we consider "pure" endoscopic transsphenoidal surgery is a procedure performed through the nose and the sphenoid bone, with the endoscope alone throughout the whole approach to visualize the surgical target area and without the use of any transsphenoidal retractor. It offers some advantages due to the endoscope itself: a superior close-up view of the relevant anatomy and an enlarged working angle are provided with an increased panoramic vision inside the surgical area. Concerning results in terms of mass removal, relief of clinical symptoms, cure of the underlying disease and complication rate, they are, at least, similar to those reported in the major microsurgical series, but patient compliance is by far better. Furthermore transsphenoidal endoscopy brings advantages to the patient (less nasal traumatism, no nasal packing, less post-op pain and usually quick recovery), to the surgeon (wider and closer view of the surgical target area, increase of the scientific activity as from the peer-reviewed literature on the topic in the last 10 years, smoothing of interdisciplinary cooperation), to the institution (shorter post-op hospital stay, increase of the case load). Besides, further progress and technological advance are expected from the close cooperation between different technologies and industries. Continuing works in such field of "minimalism" will offer further possibilities to provide the surgeon with even more effectiveness and safety, and, on the other hand, the patient with improvement of results.

57. INTERIOR VIEW OF VAL BRIDGE STRUCTURE SHOWING LAUNCHING TUBE, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

57. INTERIOR VIEW OF VAL BRIDGE STRUCTURE SHOWING LAUNCHING TUBE, STAIRS AND PORTION OF LAUNCHING DECK. NOTE SUPPORT CARRIAGE ASSEMBLY IN DISTANCE. Date unknown, circa March 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Characteristics of mist 3D screen for projection type electro-holography

NASA Astrophysics Data System (ADS)

Sato, Koki; Okumura, Toshimichi; Kanaoka, Takumi; Koizumi, Shinya; Nishikawa, Satoko; Takano, Kunihiko

2006-01-01

The specification of hologram image is the full parallax 3D image. In this case we can get more natural 3D image because focusing and convergence are coincident each other. We try to get practical electro-holography system because for conventional electro-holography the image viewing angle is very small. This is due to the limited display pixel size. Now we are developing new method for large viewing angle by space projection method. White color laser is irradiated to single DMD panel (time shared CGH of RGB three colors). 3D space screen constructed by very small water particle is used to reconstruct the 3D image with large viewing angle by scattering of water particle.

Hologram generation by horizontal scanning of a high-speed spatial light modulator.

PubMed

Takaki, Yasuhiro; Okada, Naoya

2009-06-10

In order to increase the image size and the viewing zone angle of a hologram, a high-speed spatial light modulator (SLM) is imaged as a vertically long image by an anamorphic imaging system, and this image is scanned horizontally by a galvano scanner. The reduction in horizontal pixel pitch of the SLM provides a wide viewing zone angle. The increased image height and horizontal scanning increased the image size. We demonstrated the generation of a hologram having a 15 degrees horizontal viewing zone angle and an image size of 3.4 inches with a frame rate of 60 Hz using a digital micromirror device with a frame rate of 13.333 kHz as a high-speed SLM.

On the viewing angle dependence of blazar variability

NASA Astrophysics Data System (ADS)

Eldar, Avigdor; Levinson, Amir

2000-05-01

Internal shocks propagating through an ambient radiation field are subject to a radiative drag that, under certain conditions, can significantly affect their dynamics, and consequently the evolution of the beaming cone of emission produced behind the shocks. The resultant change of the Doppler factor combined with opacity effects leads to a strong dependence on the viewing angle of the variability pattern produced by such systems; specifically, the shape of the light curves and the characteristics of correlated emission. One implication is that objects oriented at relatively large viewing angles to the observer should exhibit a higher level of activity at high synchrotron frequencies (above the self-absorption frequency), and also at gamma-ray energies below the threshold energy of pair production, than at lower (radio/millimetre) frequencies.

Angle Measurement of Objects outside the Linear Field of View of a Strapdown Semi-Active Laser Seeker.

PubMed

Zheng, Yongbin; Chen, Huimin; Zhou, Zongtan

2018-05-23

The accurate angle measurement of objects outside the linear field of view (FOV) is a challenging task for a strapdown semi-active laser seeker and is not yet well resolved. Considering the fact that the strapdown semi-active laser seeker is equipped with GPS and an inertial navigation system (INS) on a missile, in this work, we present an angle measurement method based on the fusion of the seeker’s data and GPS and INS data for a strapdown semi-active laser seeker. When an object is in the nonlinear FOV or outside the FOV, by solving the problems of space consistency and time consistency, the pitch angle and yaw angle of the object can be calculated via the fusion of the last valid angles measured by the seeker and the corresponding GPS and INS data. The numerical simulation results demonstrate the correctness and effectiveness of the proposed method.

Concept development for the ITER equatorial port visible/infrared wide angle viewing system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reichle, R.; Beaumont, B.; Boilson, D.

2012-10-15

The ITER equatorial port visible/infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R and D topicsmore » are outlined.« less

Defining Constellation Suit Helmet Field of View Requirements Employing a Mission Segment Based Reduction Process

NASA Technical Reports Server (NTRS)

McFarland, Shane M.

2008-01-01

Field of view has always been a design feature paramount to helmet design, and in particular space suit design, where the helmet must provide an adequate field of view for a large range of activities, environments, and body positions. For Project Constellation, a slightly different approach to helmet requirement maturation was utilized; one that was less a direct function of body position and suit pressure and more a function of the mission segment in which the field of view is required. Through taxonimization of various parameters that affect suited FOV, as well as consideration for possible nominal and contingency operations during that mission segment, a reduction process was able to condense the large number of possible outcomes to only six unique field of view angle requirements that still captured all necessary variables without sacrificing fidelity. The specific field of view angles were defined by considering mission segment activities, historical performance of other suits, comparison between similar requirements (pressure visor up versus down, etc.), estimated requirements from other teams for field of view (Orion, Altair, EVA), previous field of view tests, medical data for shirtsleeve field of view performance, and mapping of visual field data to generate 45degree off-axis field of view requirements. Full resolution of several specific field of view angle requirements warranted further work, which consisted of low and medium fidelity field of view testing in the rear entry ISuit and DO27 helmet prototype. This paper serves to document this reduction progress and followup testing employed to write the Constellation requirements for helmet field of view.

Biophysical and spectral modeling for crop identification and assessment

NASA Technical Reports Server (NTRS)

Goel, N. S. (Principal Investigator)

1984-01-01

The development of a technique for estimating all canopy parameters occurring in a canopy reflectance model from the measured canopy reflectance data is summarized. The Suits and the SAIL model for a uniform and homogeneous crop canopy were used to determine if the leaf area index and the leaf angle distribution could be estimated. Optimal solar/view angles for measuring CR were also investigated. The use of CR in many wavelengths or spectral bands and of linear and nonlinear transforms of CRs for various solar/view angles and various spectral bands is discussed as well as the inversion of rediance data inside the canopy, angle transforms for filtering out terrain slope effects, and modification of one dimensional models.

Experimental light scattering by positionally-controlled small particles — Implications for Planetary Science

NASA Astrophysics Data System (ADS)

Gritsevich, M.; Penttilä, A.; Maconi, G.; Kassamakov, I.; Martikainen, J.; Markkanen, J.; Vaisanen, T.; Helander, P.; Puranen, T.; Salmi, A.; Hæggström, E.; Muinonen, K.

2017-12-01

Electromagnetic scattering is a fundamental physical process that allows inferring characteristics of an object studied remotely. This possibility is enhanced by obtaining the light-scattering response at multiple wavelengths and viewing geometries, i.e., by considering a wider range of the phase angle (the angle between the incident light and the light reflected from the object) in the experiment. Within the ERC Advanced Grant project SAEMPL (http://cordis.europa.eu/project/rcn/107666_en.html) we have assembled an interdisciplinary group of scientists to develop a fully automated, 3D scatterometer that can measure scattered light at different wavelengths from small particulate samples. The setup comprises: (a) the PXI Express platform to synchronously record data from several photomultiplier tubes (PMTs); (b) a motorized rotation stage to precisely control the azimuthal angle of the PMTs around 360°; and (c) a versatile light source, whose wavelength, polarization, intensity, and beam shape can be precisely controlled. An acoustic levitator is used to hold the sample without touching it. The device is the first of its kind, since it measures controlled spectral angular scattering including all polarization effects, for an arbitrary object in the µm-cm size scale. It permits a nondestructive, disturbance-free measurement with control of the orientation and location of the scattering object. To demonstrate our approach we performed detailed measurements of light scattered by a Chelyabinsk LL5 chondrite particle, derived from the light-colored lithology sample of the meteorite. These measurements are cross-validated against the modeled light-scattering characteristics of the sample, i.e., the intensity and the degree of linear polarization of the reflected light, calculated with state-of-the-art electromagnetic techniques (see Muinonen et al., this meeting). We demonstrate a unique non-destructive approach to derive the optical properties of small grain samples which facilitates research on highly valuable planetary materials, such as samples returned from space missions or rare meteorites.

Networking Hospital ePrescribing: A Systemic View of Digitalization of Medicines' Use in England.

PubMed

Lichtner, Valentina; Hibberd, Ralph; Cornford, Tony

2016-01-01

Medicine management is at the core of hospital care and digitalization of prescribing and administration of medicines is often the focus of attention of health IT programs. This may be conveyed to the public in terms of the elimination of paper-based drug charts and increased readability of doctors' prescriptions. Based on analysis of documents about hospital medicines supply and use (including systems' implementation) in the UK, in this conceptual paper electronic prescribing and administration are repositioned as only one aspect of an important wider transformation in medicine management in hospital settings, involving, for example, procurement, dispensing, auditing, waste management, research and safety vigilance. Approaching digitalization from a systemic perspective has the potential to uncover the wider implications of this transformation for patients, the organization and the wider health care system.

Ash from Kilauea Eruption Viewed by NASA's MISR

Atmospheric Science Data Center

2018-06-07

... title:  Ash from Kilauea Eruption Viewed by NASA's MISR View Larger Image   Ash ... Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite captured this view of the island as it passed overhead. ...

Three-dimensional imaging from a unidirectional hologram: wide-viewing-zone projection type.

PubMed

Okoshi, T; Oshima, K

1976-04-01

In ordinary holography reconstructing a virtual image, the hologram must be wider than either the visual field or the viewing zone. In this paper, an economical method of recording a wide-viewing-zone wide-visual-field 3-D holographic image is proposed. In this method, many mirrors are used to collect object waves onto a small hologram. In the reconstruction, a real image from the hologram is projected onto a horizontally direction-selective stereoscreen through the same mirrors. In the experiment, satisfactory 3-D images have been observed from a wide viewing zone. The optimum design and information reduction techniques are also discussed.

Off-resonance artifacts correction with convolution in k-space (ORACLE).

PubMed

Lin, Wei; Huang, Feng; Simonotto, Enrico; Duensing, George R; Reykowski, Arne

2012-06-01

Off-resonance artifacts hinder the wider applicability of echo-planar imaging and non-Cartesian MRI methods such as radial and spiral. In this work, a general and rapid method is proposed for off-resonance artifacts correction based on data convolution in k-space. The acquired k-space is divided into multiple segments based on their acquisition times. Off-resonance-induced artifact within each segment is removed by applying a convolution kernel, which is the Fourier transform of an off-resonance correcting spatial phase modulation term. The field map is determined from the inverse Fourier transform of a basis kernel, which is calibrated from data fitting in k-space. The technique was demonstrated in phantom and in vivo studies for radial, spiral and echo-planar imaging datasets. For radial acquisitions, the proposed method allows the self-calibration of the field map from the imaging data, when an alternating view-angle ordering scheme is used. An additional advantage for off-resonance artifacts correction based on data convolution in k-space is the reusability of convolution kernels to images acquired with the same sequence but different contrasts. Copyright © 2011 Wiley-Liss, Inc.

Bunionette deformity.

PubMed

Cohen, Bruce E; Nicholson, Christopher W

2007-05-01

The bunionette, or tailor's bunion, is a lateral prominence of the fifth metatarsal head. Most commonly, bunionettes are the result of a widened 4-5 intermetatarsal angle with associated varus of the metatarsophalangeal joint. When symptomatic, these deformities often respond to nonsurgical treatment methods, such as wider shoes and padding techniques. When these methods are unsuccessful, surgical treatment is based on preoperative radiographs and associated lesions, such as hyperkeratoses. In rare situations, a simple lateral eminence resection is appropriate; however, the risk of recurrence or overresection is high with this technique. Patients with a lateral bow to the fifth metatarsal are treated with a distal chevron-type osteotomy. A widened 4-5 intermetatarsal angle often requires a diaphyseal osteotomy for correction.

3. Elevation view of entire midsection using ultrawide angle lens. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Elevation view of entire midsection using ultrawide angle lens. Note opened south doors and closed north doors. The following photo WA-203-C-4 is similar except the camera position was moved right to include the slope of the south end. - Puget Sound Naval Shipyard, Munitions Storage Bunker, Naval Ammunitions Depot, South of Campbell Trail, Bremerton, Kitsap County, WA

Dynamic foot function and morphology in elite rugby league athletes of different ethnicity.

PubMed

Gurney, Jason K; Kersting, Uwe G; Rosenbaum, Dieter

2009-05-01

It has long been assumed that foot function and morphology differ between ethnicities. However, quantitative research proving or disproving this relationship is sparse. As a starting point, the objective of this study was to investigate the plantar loading characteristics and foot geometry of athletes from three ethnicities, being Caucasian, Maori and Pacific Islanders. Four plantar pressure parameters were compared in 28 male elite rugby league players using an EMED-AT plantar pressure distribution platform [Novel GmbH, Munich, Germany] and the five-step method. Foot geometry measures were also taken, including arch index, coefficient of spreading, hallux angle and sub-arch angle. Five trials were collected per foot at a self-selected speed. It was found that Caucasian and Maori subjects had a relatively wider forefoot than the Pacific Island subjects; however the Pacific Islanders' foot was found to be wider than both these ethnicities in absolute terms. While Caucasian subjects loaded the toes to a much greater extent than the Maori and Pacific Island subjects, the latter demonstrated a greater loading of the mid and forefoot regions. Pacific Island subjects revealed a significantly more pronounced hallux valgus angle as compared to the Caucasian and Maori subjects. The results of this study may be relevant for/should be taken into consideration in footwear design issues, where allowances need to be made during the design process for anatomical differences between ethnicities. However these observations cannot be generalised to whole ethnic populations, and further research is required on non-athletes to build on the current research findings.

An anatomical analysis of the mini-modified orbitozygomatic and supra-orbital approaches.

PubMed

Figueiredo, Eberval G; Deshmukh, Puspha; Nakaji, Peter; Shu, Edson Bor Seng; Crawford, Neil; Spetzler, Robert F; Preul, Mark C

2012-11-01

Seven sides of cadaver heads were used to compare the surgical exposures provided by the mini-modified orbitozygomatic (MOz) and supra-orbital (SO) approaches. The Optotrak 3020 computerized tracking system (Northern Digital, Waterloo, ON, Canada) was utilized to evaluate the area of anatomical exposure defined by six points: (1) ipsilateral sphenoid ridge; (2) most distal point of the ipsilateral middle cerebral artery (MCA); (3) most distal point of the ipsilateral posterior cerebral artery (PCA); (4) most distal point of the contralateral PCA; (5) most distal point of the contralateral MCA; and (6) contralateral sphenoid ridge. Additionally, angles of approach for the ipsilateral MCA bifurcation, ipsilateral ICA bifurcation, basilar artery tip, contralateral MCA and ICA bifurcation and anterior communicating artery (AcomA) were evaluated, first for SO and then for MOz. An image guidance system was used to evaluate the limits of surgical exposure. No differences in the area of surgical exposure were noted (p>0.05). Vertical angles were significantly wider for the ipsilateral and contralateral ICA bifurcation, AcomA, contralateral MCA and basilar tip (p<0.05) for MOz. No differences in horizontal angles were observed between the approaches for the six targets (p>0.05). There were no differences in the limits of exposure. MOz affords no additional surgical working space. However, our results demonstrate systematically that vertical exposure is improved. The MOz should be performed while planning an approach to these regions and a wider exposure in the vertical axis is needed. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Case for Contextual Learning.

ERIC Educational Resources Information Center

Souders, John; Prescott, Carolyn

1999-01-01

Establishing schooling/larger world connections is critical for adolescents. The contextual learning approach views learning as most effective when information is presented within a familiar framework. Employing puzzles, hands-on learning activities, project-based learning, contextual connections, applied math, mentoring, and wider audiences…

The pigeon's distant visual acuity as a function of viewing angle.

PubMed

Uhlrich, D J; Blough, P M; Blough, D S

1982-01-01

Distant visual acuity was determined for several viewing angles in two restrained White Carneaux pigeons. The behavioral technique was a classical conditioning procedure that paired presentation of sinusoidal gratings with shock. A conditioned heart rate acceleration during the grating presentation indicated resolution of the grating. The bird's acuity was fairly uniform across a large range of their lateral visual field; performance decreased slightly for posterior stimulus placement and sharply for frontal placements. The data suggest that foveal viewing is relatively less advantageous for acuity in pigeons than in humans. The data are also consistent with the current view that pigeons are myopic in frontal vision.

Reduction of skylight reflection effects in the above-water measurement of diffuse marine reflectance: comment.

PubMed

Krotkov, N A; Vasilkov, A P

2000-03-20

Use of a vertical polarizer has been suggested to reduce the effects of surface reflection in the above-water measurements of marine reflectance. We suggest using a similar technique for airborne or spaceborne sensors when atmospheric scattering adds its own polarization signature to the upwelling radiance. Our own theoretical sensitivity study supports the recommendation of Fougnie et al. [Appl. Opt. 38, 3844 (1999)] (40-50 degrees vertical angle and azimuth angle near 135 degrees, polarizer parallel to the viewing plane) for above-water measurements. However, the optimal viewing directions (and the optimal orientation of the polarizer) change with altitude above the sea surface, solar angle, and atmospheric vertical optical structure. A polarization efficiency function is introduced, which shows the maximal possible polarization discrimination of the background radiation for an arbitrary altitude above the sea surface, viewing direction, and solar angle. Our comment is meant to encourage broader application of airborne and spaceborne polarization sensors in remote sensing of water and sea surface properties.

Integrated large view angle hologram system with multi-slm

NASA Astrophysics Data System (ADS)

Yang, ChengWei; Liu, Juan

2017-10-01

Recently holographic display has attracted much attention for its ability to generate real-time 3D reconstructed image. CGH provides an effective way to produce hologram, and spacial light modulator (SLM) is used to reconstruct the image. However the reconstructing system is usually very heavy and complex, and the view-angle is limited by the pixel size and spatial bandwidth product (SBP) of the SLM. In this paper a light portable holographic display system is proposed by integrating the optical elements and host computer units.Which significantly reduces the space taken in horizontal direction. CGH is produced based on the Fresnel diffraction and point source method. To reduce the memory usage and image distortion, we use an optimized accurate compressed look up table method (AC-LUT) to compute the hologram. In the system, six SLMs are concatenated to a curved plane, each one loading the phase-only hologram in a different angle of the object, the horizontal view-angle of the reconstructed image can be expanded to about 21.8°.

A Wide Field of View Plasma Spectrometer

DOE PAGES

Skoug, Ruth M.; Funsten, Herbert O.; Moebius, Eberhard; ...

2016-07-01

Here we present a fundamentally new type of space plasma spectrometer, the wide field of view plasma spectrometer, whose field of view is >1.25π ster using fewer resources than traditional methods. The enabling component is analogous to a pinhole camera with an electrostatic energy-angle filter at the image plane. Particle energy-per-charge is selected with a tunable bias voltage applied to the filter plate relative to the pinhole aperture plate. For a given bias voltage, charged particles from different directions are focused by different angles to different locations. Particles with appropriate locations and angles can transit the filter plate and aremore » measured using a microchannel plate detector with a position-sensitive anode. Full energy and angle coverage are obtained using a single high-voltage power supply, resulting in considerable resource savings and allowing measurements at fast timescales. Lastly, we present laboratory prototype measurements and simulations demonstrating the instrument concept and discuss optimizations of the instrument design for application to space measurements.« less

NIMROD: The Near and InterMediate Range Order Diffractometer of the ISIS second target station.

PubMed

Bowron, D T; Soper, A K; Jones, K; Ansell, S; Birch, S; Norris, J; Perrott, L; Riedel, D; Rhodes, N J; Wakefield, S R; Botti, A; Ricci, M-A; Grazzi, F; Zoppi, M

2010-03-01

NIMROD is the Near and InterMediate Range Order Diffractometer of the ISIS second target station. Its design is optimized for structural studies of disordered materials and liquids on a continuous length scale that extends from the atomic, upward of 30 nm, while maintaining subatomic distance resolution. This capability is achieved by matching a low and wider angle array of high efficiency neutron scintillation detectors to the broad band-pass radiation delivered by a hybrid liquid water and liquid hydrogen neutron moderator assembly. The capabilities of the instrument bridge the gap between conventional small angle neutron scattering and wide angle diffraction through the use of a common calibration procedure for the entire length scale. This allows the instrument to obtain information on nanoscale systems and processes that are quantitatively linked to the local atomic and molecular order of the materials under investigation.

Thin plate spline feature point matching for organ surfaces in minimally invasive surgery imaging

NASA Astrophysics Data System (ADS)

Lin, Bingxiong; Sun, Yu; Qian, Xiaoning

2013-03-01

Robust feature point matching for images with large view angle changes in Minimally Invasive Surgery (MIS) is a challenging task due to low texture and specular reflections in these images. This paper presents a new approach that can improve feature matching performance by exploiting the inherent geometric property of the organ surfaces. Recently, intensity based template image tracking using a Thin Plate Spline (TPS) model has been extended for 3D surface tracking with stereo cameras. The intensity based tracking is also used here for 3D reconstruction of internal organ surfaces. To overcome the small displacement requirement of intensity based tracking, feature point correspondences are used for proper initialization of the nonlinear optimization in the intensity based method. Second, we generate simulated images from the reconstructed 3D surfaces under all potential view positions and orientations, and then extract feature points from these simulated images. The obtained feature points are then filtered and re-projected to the common reference image. The descriptors of the feature points under different view angles are stored to ensure that the proposed method can tolerate a large range of view angles. We evaluate the proposed method with silicon phantoms and in vivo images. The experimental results show that our method is much more robust with respect to the view angle changes than other state-of-the-art methods.

Dental cone-beam CT reconstruction from limited-angle view data based on compressed-sensing (CS) theory for fast, low-dose X-ray imaging

NASA Astrophysics Data System (ADS)

Je, Uikyu; Cho, Hyosung; Lee, Minsik; Oh, Jieun; Park, Yeonok; Hong, Daeki; Park, Cheulkyu; Cho, Heemoon; Choi, Sungil; Koo, Yangseo

2014-06-01

Recently, reducing radiation doses has become an issue of critical importance in the broader radiological community. As a possible technical approach, especially, in dental cone-beam computed tomography (CBCT), reconstruction from limited-angle view data (< 360°) would enable fast scanning with reduced doses to the patient. In this study, we investigated and implemented an efficient reconstruction algorithm based on compressed-sensing (CS) theory for the scan geometry and performed systematic simulation works to investigate the image characteristics. We also performed experimental works by applying the algorithm to a commercially-available dental CBCT system to demonstrate its effectiveness for image reconstruction in incomplete data problems. We successfully reconstructed CBCT images with incomplete projections acquired at selected scan angles of 120, 150, 180, and 200° with a fixed angle step of 1.2° and evaluated the reconstruction quality quantitatively. Both simulation and experimental demonstrations of the CS-based reconstruction from limited-angle view data show that the algorithm can be applied directly to current dental CBCT systems for reducing the imaging doses and further improving the image quality.

Sailing on the "Boundless and Bottomless Sea": A View from the OIA Bridge

ERIC Educational Resources Information Center

Behrens, Rob

2015-01-01

The prevention and resolution of student complaints are critical factors in maintaining and improving the student experience. Rob Behrens looks at the wider context, drawing on lessons from beyond higher education, to examine the opportunities and possible pitfalls.

Case studies of aerosol and ocean color retrieval using a Markov chain radiative transfer model and AirMSPI measurements

NASA Astrophysics Data System (ADS)

Xu, F.; Diner, D. J.; Seidel, F. C.; Dubovik, O.; Zhai, P.

2014-12-01

A vector Markov chain radiative transfer method was developed for forward modeling of radiance and polarization fields in a coupled atmosphere-ocean system. The method was benchmarked against an independent Successive Orders of Scattering code and linearized through the use of Jacobians. Incorporated with the multi-patch optimization algorithm and look-up-table method, simultaneous aerosol and ocean color retrievals were performed using imagery acquired by the Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) when it was operated in step-and-stare mode with 9 viewing angles ranging between ±67°. Data from channels near 355, 380, 445, 470*, 555, 660*, and 865* nm were used in the retrievals, where the asterisk denotes the polarimetric bands. Retrievals were run for AirMSPI overflights over Southern California and Monterey Bay, CA. For the relatively high aerosol optical depth (AOD) case (~0.28 at 550 nm), the retrieved aerosol concentration, size distribution, water-leaving radiance, and chlorophyll concentration were compared to those reported by the USC SeaPRISM AERONET-OC site off the coast of Southern California on 6 February 2013. For the relatively low AOD case (~0.08 at 550 nm), the retrieved aerosol concentration and size distribution were compared to those reported by the Monterey Bay AERONET site on 28 April 2014. Further, we evaluate the benefits of multi-angle and polarimetric observations by performing the retrievals using (a) all view angles and channels; (b) all view angles but radiances only (no polarization); (c) the nadir view angle only with both radiance and polarization; and (d) the nadir view angle without polarization. Optimized retrievals using different initial guesses were performed to provide a measure of retrieval uncertainty. Removal of multi-angular or polarimetric information resulted in increases in both parameter uncertainty and systematic bias. Potential accuracy improvements afforded by applying constraints on the surface and aerosol parametric models will also be discussed.

Use of a microscope-mounted wide-angle point of view camera to record optimal hand position in ocular surgery.

PubMed

Gooi, Patrick; Ahmed, Yusuf; Ahmed, Iqbal Ike K

2014-07-01

We describe the use of a microscope-mounted wide-angle point-of-view camera to record optimal hand positions in ocular surgery. The camera is mounted close to the objective lens beneath the surgeon's oculars and faces the same direction as the surgeon, providing a surgeon's view. A wide-angle lens enables viewing of both hands simultaneously and does not require repositioning the camera during the case. Proper hand positioning and instrument placement through microincisions are critical for effective and atraumatic handling of tissue within the eye. Our technique has potential in the assessment and training of optimal hand position for surgeons performing intraocular surgery. It is an innovative way to routinely record instrument and operating hand positions in ophthalmic surgery and has minimal requirements in terms of cost, personnel, and operating-room space. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

On-orbit Characterization of RVS for MODIS Thermal Emissive Bands

NASA Technical Reports Server (NTRS)

Xiong, X.; Salomonson, V.; Chiang, K.; Wu, A.; Guenther, B.; Barnes, W.

2004-01-01

Response versus scan angle (RVS) is a key calibration parameter for remote sensing radiometers that make observations using a scanning optical system, such as a scan mirror in MODIS and GLI or a rotating telescope in SeaWiFS and VIIRS, since the calibration is typically performed at a fixed viewing angle while the Earth scene observations are made over a range of viewing angles. Terra MODIS has been in operation for more than four years since its launch in December 1999. It has 36 spectral bands covering spectral range from visible (VIS) to long-wave infrared (LWIR). It is a cross-track scanning radiometer using a two-sided paddle wheel scan mirror, making observations over a wide field of view (FOV) of +/-55 deg from the instrument nadir. This paper describes on-orbit characterization of MODIS RVS for its thermal emissive bands (TEB), using the Earth view data collected during Terra spacecraft deep space maneuvers (DSM). Comparisons with pre-launch analysis and early on-orbit measurements are also provided.

Deformation of Fold-and-Thrust Belts above a Viscous Detachment: New Insights from Analogue Modelling Experiments

NASA Astrophysics Data System (ADS)

Nogueira, Carlos R.; Marques, Fernando O.

2015-04-01

Theoretical and experimental studies on fold-and-thrusts belts (FTB) have shown that, under Coulomb conditions, deformation of brittle thrust wedges above a dry frictional basal contact is characterized by dominant frontward vergent thrusts (forethrusts) with thrust spacing and taper angle being directly influenced by the basal strength (increase in basal strength leading to narrower thrust spacing and higher taper angles); whereas thrust wedges deformed above a weak viscous detachment, such as salt, show a more symmetric thrust style (no prevailing vergence of thrusting) with wider thrust spacing and shallower wedges. However, different deformation patterns can be found on this last group of thrust wedges both in nature and experimentally. Therefore we focused on the strength (friction) of the wedge basal contact, the basal detachment. We used a parallelepiped box with four fixed walls and one mobile that worked as a vertical piston drove by a computer controlled stepping motor. Fine dry sand was used as the analogue of brittle rocks and silicone putty (PDMS) with Newtonian behaviour as analogue of the weak viscous detachment. To investigate the strength of basal contact on thrust wedge deformation, two configurations were used: 1) a horizontal sand pack with a dry frictional basal contact; and 2) a horizontal sand pack above a horizontal PDMS layer, acting as a basal weak viscous contact. Results of the experiments show that: the model with a dry frictional basal detachment support the predictions for the Coulomb wedges, showing a narrow wedge with dominant frontward vergence of thrusting, close spacing between FTs and high taper angle. The model with a weak viscous frictional basal detachment show that: 1) forethrusts (FT) are dominant showing clearly an imbricate asymmetric geometry, with wider spaced thrusts than the dry frictional basal model; 2) after FT initiation, the movement on the thrust can last up to 15% model shortening, leading to great amount of displacement along the FT; 3) intermittent reactivation of FTs also occurs despite the steepening of the FT plane and existence of new FT ahead, creating a high critical taper angle; 4) injection of PDMS from the basal weak layer into the FTs planes also favours to the long living of FTs and to the high critical taper angle; 5) vertical sand thickening in the hanging block also added to the taper angle.

NPP VIIRS on-orbit calibration and characterization using the moon

NASA Astrophysics Data System (ADS)

Sun, J.; Xiong, X.; Butler, J.

2012-09-01

The Visible Infrared Imager Radiometer Suite (VIIRS) is one of five instruments on-board the Suomi National Polarorbiting Partnership (NPP) satellite that launched from Vandenberg Air Force Base, Calif., on Oct. 28, 2011. VIIRS has been scheduled to view the Moon approximately monthly with a spacecraft roll maneuver after its NADIR door open on November 21, 2012. To reduce the uncertainty of the radiometric calibration due to the view geometry, the lunar phase angles of the scheduled lunar observations were confined in the range from -56° to -55° in the first three scheduled lunar observations and then changed to the range from -51.5° to -50.5°, where the negative sign for the phase angles indicates that the VIIRS views a waxing moon. Unlike the MODIS lunar observations, most scheduled VIIRS lunar views occur on the day side of the Earth. For the safety of the instrument, the roll angles of the scheduled VIIRS lunar observations are required to be within [-14°, 0°] and the aforementioned change of the phase angle range was aimed to further minimize the roll angle required for each lunar observation while keeping the number of months in which the moon can be viewed by the VIIRS instrument each year unchanged. The lunar observations can be used to identify if there is crosstalk in VIIRS bands and to track on-orbit changes in VIIRS Reflective Solar Bands (RSB) detector gains. In this paper, we report our results using the lunar observations to examine the on-orbit crosstalk effects among NPP VIIRS bands, to track the VIIRS RSB gain changes in first few months on-orbit, and to compare the gain changes derived from lunar and SD/SDSM calibration.

NPP VIIRS On-Orbit Calibration and Characterization Using the Moon

NASA Technical Reports Server (NTRS)

Sun, J.; Xiong, X.; Butler, J.

2012-01-01

The Visible Infrared Imager Radiometer Suite (VIIRS) is one of five instruments on-board the Suomi National Polar orbiting Partnership (NPP) satellite that launched from Vandenberg Air Force Base, Calif., on Oct. 28, 2011. VIIRS has been scheduled to view the Moon approximately monthly with a spacecraft roll maneuver after its NADIR door open on November 21, 2011. To reduce the uncertainty of the radiometric calibration due to the view geometry, the lunar phase angles of the scheduled lunar observations were confined in the range from -56 deg to -55 deg in the first three scheduled lunar observations and then changed to the range from -51.5 deg to -50.5 deg, where the negative sign for the phase angles indicates that the VIIRS views a waxing moon. Unlike the MODIS lunar observations, most scheduled VIIRS lunar views occur on the day side of the Earth. For the safety of the instrument, the roll angles of the scheduled VIIRS lunar observations are required to be within [-14 deg, 0 deg] and the aforementioned change of the phase angle range was aimed to further minimize the roll angle required for each lunar observation while keeping the number of months in which the moon can be viewed by the VIIRS instrument each year unchanged. The lunar observations can be used to identify if there is crosstalk in VIIRS bands and to track on-orbit changes in VIIRS Reflective Solar Bands (RSB) detector gains. In this paper, we report our results using the lunar observations to examine the on-orbit crosstalk effects among NPP VIIRS bands, to track the VIIRS RSB gain changes in first few months on-orbit, and to compare the gain changes derived from lunar and SD/SDSM calibration.

Utility of BRDF Models for Estimating Optimal View Angles in Classification of Remotely Sensed Images

NASA Technical Reports Server (NTRS)

Valdez, P. F.; Donohoe, G. W.

1997-01-01

Statistical classification of remotely sensed images attempts to discriminate between surface cover types on the basis of the spectral response recorded by a sensor. It is well known that surfaces reflect incident radiation as a function of wavelength producing a spectral signature specific to the material under investigation. Multispectral and hyperspectral sensors sample the spectral response over tens and even hundreds of wavelength bands to capture the variation of spectral response with wavelength. Classification algorithms then exploit these differences in spectral response to distinguish between materials of interest. Sensors of this type, however, collect detailed spectral information from one direction (usually nadir); consequently, do not consider the directional nature of reflectance potentially detectable at different sensor view angles. Improvements in sensor technology have resulted in remote sensing platforms capable of detecting reflected energy across wavelengths (spectral signatures) and from multiple view angles (angular signatures) in the fore and aft directions. Sensors of this type include: the moderate resolution imaging spectroradiometer (MODIS), the multiangle imaging spectroradiometer (MISR), and the airborne solid-state array spectroradiometer (ASAS). A goal of this paper, then, is to explore the utility of Bidirectional Reflectance Distribution Function (BRDF) models in the selection of optimal view angles for the classification of remotely sensed images by employing a strategy of searching for the maximum difference between surface BRDFs. After a brief discussion of directional reflect ante in Section 2, attention is directed to the Beard-Maxwell BRDF model and its use in predicting the bidirectional reflectance of a surface. The selection of optimal viewing angles is addressed in Section 3, followed by conclusions and future work in Section 4.

Measuring contact angle and meniscus shape with a reflected laser beam.

PubMed

Eibach, T F; Fell, D; Nguyen, H; Butt, H J; Auernhammer, G K

2014-01-01

Side-view imaging of the contact angle between an extended planar solid surface and a liquid is problematic. Even when aligning the view perfectly parallel to the contact line, focusing one point of the contact line is not possible. We describe a new measurement technique for determining contact angles with the reflection of a widened laser sheet on a moving contact line. We verified this new technique measuring the contact angle on a cylinder, rotating partially immersed in a liquid. A laser sheet is inclined under an angle φ to the unperturbed liquid surface and is reflected off the meniscus. Collected on a screen, the reflection image contains information to determine the contact angle. When dividing the laser sheet into an array of laser rays by placing a mesh into the beam path, the shape of the meniscus can be reconstructed from the reflection image. We verified the method by measuring the receding contact angle versus speed for aqueous cetyltrimethyl ammonium bromide solutions on a smooth hydrophobized as well as on a rough polystyrene surface.

Measuring contact angle and meniscus shape with a reflected laser beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eibach, T. F.; Nguyen, H.; Butt, H. J.

2014-01-15

Side-view imaging of the contact angle between an extended planar solid surface and a liquid is problematic. Even when aligning the view perfectly parallel to the contact line, focusing one point of the contact line is not possible. We describe a new measurement technique for determining contact angles with the reflection of a widened laser sheet on a moving contact line. We verified this new technique measuring the contact angle on a cylinder, rotating partially immersed in a liquid. A laser sheet is inclined under an angle φ to the unperturbed liquid surface and is reflected off the meniscus. Collectedmore » on a screen, the reflection image contains information to determine the contact angle. When dividing the laser sheet into an array of laser rays by placing a mesh into the beam path, the shape of the meniscus can be reconstructed from the reflection image. We verified the method by measuring the receding contact angle versus speed for aqueous cetyltrimethyl ammonium bromide solutions on a smooth hydrophobized as well as on a rough polystyrene surface.« less

Sensitivity of MODIS 2.1 micron Channel for Off-Nadir View Angles for Use in Remote Sensing of Aerosol

NASA Technical Reports Server (NTRS)

Gatebe, C. K.; King, M. D.; Tsay, S.-C.; Ji, Q.

2000-01-01

Remote sensing of aerosol over land, from MODIS will be based on dark targets using mid-IR channels 2.1 and 3.9 micron. This approach was developed by Kaufman et al (1997), who suggested that dark surface reflectance in the red (0.66 micron -- rho(sub 0.66)) channel is half of that at 2.2 micron (rho(sub 2.2)), and the reflectance in the blue (0.49 micron - rho(sub 0.49)) channel is a quarter of that at 2.2 micron. Using this relationship, the surface reflectance in the visible channels can be predicted within Delta.rho(sub 0.49) approximately Delat.rho(sub 0.66) approximately 0.006 from rho(sub 2.2) for rho(sub 2.2) <= 0.10. This was half the error obtained using the 3.75 micron and corresponds to an error in aerosol optical thickness of Delat.tau approximately 0.06. These results, though applicable to several biomes (e.g. forests, and brighter lower canopies), have only been tested at one view angle - the nadir (theta = 0 deg). Considering the importance of the results in remote sensing of aerosols over land surfaces from space, we are validating the relationships for off-nadir view angles using Cloud Absorption Radiometer (CAR) data. The CAR data are available for channels between 0.3 and 2.3 micron and for different surface types and conditions: forest, tundra, ocean, sea-ice, swamp, grassland and over areas covered with smoke. In this study we analyzed data collected during the Smoke, Clouds, and Radiation - Brazil (SCAR-B) experiment to validate Kaufman et al.'s (1997) results for non-nadir view angles. We will show the correlation between rho(sub 0.472), rho(sub 0.675), and rho(sub 2.2) for view angles between nadir (0 deg) and 55 deg off-nadir, and for different viewing directions in the backscatter and forward scatter directions.

On Local Ionization Equilibrium and Disk Winds in QSOs

NASA Astrophysics Data System (ADS)

Pereyra, Nicolas A.

2014-11-01

We present theoretical C IV λλ1548,1550 absorption line profiles for QSOs calculated assuming the accretion disk wind (ADW) scenario. The results suggest that the multiple absorption troughs seen in many QSOs may be due to the discontinuities in the ion balance of the wind (caused by X-rays), rather than discontinuities in the density/velocity structure. The profiles are calculated from a 2.5-dimensional time-dependent hydrodynamic simulation of a line-driven disk wind for a typical QSO black hole mass, a typical QSO luminosity, and for a standard Shakura-Sunyaev disk. We include the effects of ionizing X-rays originating from within the inner disk radius by assuming that the wind is shielded from the X-rays from a certain viewing angle up to 90° ("edge on"). In the shielded region, we assume constant ionization equilibrium, and thus constant line-force parameters. In the non-shielded region, we assume that both the line-force and the C IV populations are nonexistent. The model can account for P-Cygni absorption troughs (produced at edge on viewing angles), multiple absorption troughs (produced at viewing angles close to the angle that separates the shielded region and the non-shielded region), and for detached absorption troughs (produced at an angle in between the first two absorption line types); that is, the model can account for the general types of broad absorption lines seen in QSOs as a viewing angle effect. The steady nature of ADWs, in turn, may account for the steady nature of the absorption structure observed in multiple-trough broad absorption line QSOs. The model parameters are M bh = 109 M ⊙ and L disk = 1047 erg s-1.

Towards a Consensus View on Understanding Nanomaterials Hazards and Managing Exposure: Knowledge Gaps and Recommendations

PubMed Central

Hunt, Geoffrey; Lynch, Iseult; Cassee, Flemming; Handy, Richard D.; Fernandes, Teresa F.; Berges, Markus; Kuhlbusch, Thomas A. J.; Dusinska, Maria; Riediker, Michael

2013-01-01

The aim of this article is to present an overview of salient issues of exposure, characterisation and hazard assessment of nanomaterials as they emerged from the consensus-building of experts undertaken within the four year European Commission coordination project NanoImpactNet. The approach adopted is to consolidate and condense the findings and problem-identification in such a way as to identify knowledge-gaps and generate a set of interim recommendations of use to industry, regulators, research bodies and funders. The categories of recommendation arising from the consensual view address: significant gaps in vital factual knowledge of exposure, characterisation and hazards; the development, dissemination and standardisation of appropriate laboratory protocols; address a wide range of technical issues in establishing an adequate risk assessment platform; the more efficient and coordinated gathering of basic data; greater inter-organisational cooperation; regulatory harmonization; the wider use of the life-cycle approaches; and the wider involvement of all stakeholders in the discussion and solution-finding efforts for nanosafety. PMID:28809359

Applying Augmented Reality to a Mobile-Assisted Learning System for Martial Arts Using Kinect Motion Capture

ERIC Educational Resources Information Center

Hsu, Wen-Chun; Shih, Ju-Ling

2016-01-01

In this study, to learn the routine of Tantui, a branch of martial arts was taken as an object of research. Fitts' stages of motor learning and augmented reality (AR) were applied to a 3D mobile-assisted learning system for martial arts, which was characterized by free viewing angles. With the new system, learners could rotate the viewing angle of…

Brain activation in parietal area during manipulation with a surgical robot simulator.

PubMed

Miura, Satoshi; Kobayashi, Yo; Kawamura, Kazuya; Nakashima, Yasutaka; Fujie, Masakatsu G

2015-06-01

we present an evaluation method to qualify the embodiment caused by the physical difference between master-slave surgical robots by measuring the activation of the intraparietal sulcus in the user's brain activity during surgical robot manipulation. We show the change of embodiment based on the change of the optical axis-to-target view angle in the surgical simulator to change the manipulator's appearance in the monitor in terms of hand-eye coordination. The objective is to explore the change of brain activation according to the change of the optical axis-to-target view angle. In the experiments, we used a functional near-infrared spectroscopic topography (f-NIRS) brain imaging device to measure the brain activity of the seven subjects while they moved the hand controller to insert a curved needle into a target using the manipulator in a surgical simulator. The experiment was carried out several times with a variety of optical axis-to-target view angles. Some participants showed a significant peak (P value = 0.037, F-number = 2.841) when the optical axis-to-target view angle was 75°. The positional relationship between the manipulators and endoscope at 75° would be the closest to the human physical relationship between the hands and eyes.

Evolved atmospheric entry corridor with safety factor

NASA Astrophysics Data System (ADS)

Liang, Zixuan; Ren, Zhang; Li, Qingdong

2018-02-01

Atmospheric entry corridors are established in previous research based on the equilibrium glide condition which assumes the flight-path angle to be zero. To get a better understanding of the highly constrained entry flight, an evolved entry corridor that considers the exact flight-path angle is developed in this study. Firstly, the conventional corridor in the altitude vs. velocity plane is extended into a three-dimensional one in the space of altitude, velocity, and flight-path angle. The three-dimensional corridor is generated by a series of constraint boxes. Then, based on a simple mapping method, an evolved two-dimensional entry corridor with safety factor is obtained. The safety factor is defined to describe the flexibility of the flight-path angle for a state within the corridor. Finally, the evolved entry corridor is simulated for the Space Shuttle and the Common Aero Vehicle (CAV) to demonstrate the effectiveness of the corridor generation approach. Compared with the conventional corridor, the evolved corridor is much wider and provides additional information. Therefore, the evolved corridor would benefit more to the entry trajectory design and analysis.

Limited Angle Dual Modality Breast Imaging

NASA Astrophysics Data System (ADS)

More, Mitali J.; Li, Heng; Goodale, Patricia J.; Zheng, Yibin; Majewski, Stan; Popov, Vladimir; Welch, Benjamin; Williams, Mark B.

2007-06-01

We are developing a dual modality breast scanner that can obtain x-ray transmission and gamma ray emission images in succession at multiple viewing angles with the breast held under mild compression. These views are reconstructed and fused to obtain three-dimensional images that combine structural and functional information. Here, we describe the dual modality system and present results of phantom experiments designed to test the system's ability to obtain fused volumetric dual modality data sets from a limited number of projections, acquired over a limited (less than 180 degrees) angular range. We also present initial results from phantom experiments conducted to optimize the acquisition geometry for gamma imaging. The optimization parameters include the total number of views and the angular range over which these views should be spread, while keeping the total number of detected counts fixed. We have found that in general, for a fixed number of views centered around the direction perpendicular to the direction of compression, in-plane contrast and SNR are improved as the angular range of the views is decreased. The improvement in contrast and SNR with decreasing angular range is much greater for deeper lesions and for a smaller number of views. However, the z-resolution of the lesion is significantly reduced with decreasing angular range. Finally, we present results from limited angle tomography scans using a system with dual, opposing heads.

5. VIEW OF FRONT (WEST AND SOUTH SIDES) TO NORTHEAST. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW OF FRONT (WEST AND SOUTH SIDES) TO NORTHEAST. VIEW TO NORTHEAST. NOTE THAT LARGE TREES PREVENT MORE COMPLETE VIEW FROM BETTER ANGLE. FOR MORE COMPLETE VIEW, SEE PHOTOGRAPHIC COPY OF 1916 PHOTO, NO. ID-17-C-35. - Boise Project, Boise Project Office, 214 Broadway, Boise, Ada County, ID

Modernization of Deployable Airfield Debris Removal Equipment

DTIC Science & Technology

2017-04-01

cleared the debris away from the crater by lowering the front bucket and setting the bottom blade at a 45-deg angle. The debris was pushed...the Komatsu WA 150 baseline loader. The crater clearing process involved the loader orienting the bucket blade at approximately 45 deg to the...wider than the track’s width (Figure 30). This caused debris to run under the track and lift the equipment, potentially throwing the operator. The final

Scapular dyskinesia: evolution towards a systems-based approach

PubMed Central

Smith, Michael J

2015-01-01

Historically, scapular dyskinesia has been used to describe an isolated clinical entity whereby an abnormality in positioning, movement or function of the scapula is present. Based upon this, treatment approaches have focused on addressing local isolated muscle activity. Recently, however, there has been a progressive move towards viewing the scapula as being part of a wider system of movement that is regulated and controlled by multiple factors, including the wider kinetic chain and individual patient-centred requirements. We therefore propose a paradigm shift whereby scapular dyskinesia is seen not in isolation but is considered within the broader context of patient-centred care and an entire neuromuscular system. PMID:27583003

Complete 360° circumferential SSOCT gonioscopy of the iridocorneal angle

NASA Astrophysics Data System (ADS)

McNabb, Ryan P.; Kuo, Anthony N.; Izatt, Joseph A.

2014-02-01

The ocular iridocorneal angle is generally an optically inaccessible area when viewed directly through the cornea due to the high angle of incidence required and the large index of refraction difference between air and cornea (nair = 1.000 and ncornea = 1.376) resulting in total internal reflection. Gonioscopy allows for viewing of the angle by removing the aircornea interface through the use of a special contact lens on the eye. Gonioscopy is used clinically to visualize the angle directly but only en face. Optical coherence tomography (OCT) has been used to image the angle and deeper structures via an external approach. Typically, this imaging technique is performed by utilizing a conventional anterior segment OCT scanning system. However, instead of imaging the apex of the cornea, either the scanner or the subject is tilted such that the corneoscleral limbus is orthogonal to the optical axis of the scanner requiring multiple volumes to obtain complete circumferential coverage of the ocular angle. We developed a novel gonioscopic OCT (GOCT) system that images the entire ocular angle within a single volume via an "internal" approach through the use of a custom radially symmetric gonioscopic contact lens. We present, to our knowledge, the first complete 360° circumferential volumes of the iridocorneal angle from a direct, internal approach.

59. VIEW FROM THE NORTHEAST IN THE NORTHEAST QUADRANT. GENERAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

59. VIEW FROM THE NORTHEAST IN THE NORTHEAST QUADRANT. GENERAL VIEW OF THE RIGHT FLANK WALL. RIGHT SHOULDER ANGLE IS INCLUDED ON THE RIGHT SIDE OF THE PHOTOGRAPH. - Fort Sumter, Charleston, Charleston County, SC

Larsen B Ice Shelf

Atmospheric Science Data Center

2013-04-16

article title:  Unique Views of a Shattered Ice Shelf     View Larger Image ... views of the breakup of the northern section of the Larsen B ice shelf are shown in this image pair from the Multi-angle Imaging ...

Voyager spacecraft images of Jupiter and Saturn

NASA Technical Reports Server (NTRS)

Birnbaum, M. M.

1982-01-01

The Voyager imaging system is described, noting that it is made up of a narrow-angle and a wide-angle TV camera, each in turn consisting of optics, a filter wheel and shutter assembly, a vidicon tube, and an electronics subsystem. The narrow-angle camera has a focal length of 1500 mm; its field of view is 0.42 deg and its focal ratio is f/8.5. For the wide-angle camera, the focal length is 200 mm, the field of view 3.2 deg, and the focal ratio of f/3.5. Images are exposed by each camera through one of eight filters in the filter wheel on the photoconductive surface of a magnetically focused and deflected vidicon having a diameter of 25 mm. The vidicon storage surface (target) is a selenium-sulfur film having an active area of 11.14 x 11.14 mm; it holds a frame consisting of 800 lines with 800 picture elements per line. Pictures of Jupiter, Saturn, and their moons are presented, with short descriptions given of the area being viewed.

Rotationally Invariant Image Representation for Viewing Direction Classification in Cryo-EM

PubMed Central

Zhao, Zhizhen; Singer, Amit

2014-01-01

We introduce a new rotationally invariant viewing angle classification method for identifying, among a large number of cryo-EM projection images, similar views without prior knowledge of the molecule. Our rotationally invariant features are based on the bispectrum. Each image is denoised and compressed using steerable principal component analysis (PCA) such that rotating an image is equivalent to phase shifting the expansion coefficients. Thus we are able to extend the theory of bispectrum of 1D periodic signals to 2D images. The randomized PCA algorithm is then used to efficiently reduce the dimensionality of the bispectrum coefficients, enabling fast computation of the similarity between any pair of images. The nearest neighbors provide an initial classification of similar viewing angles. In this way, rotational alignment is only performed for images with their nearest neighbors. The initial nearest neighbor classification and alignment are further improved by a new classification method called vector diffusion maps. Our pipeline for viewing angle classification and alignment is experimentally shown to be faster and more accurate than reference-free alignment with rotationally invariant K-means clustering, MSA/MRA 2D classification, and their modern approximations. PMID:24631969

Imminent Approach to Dione

NASA Image and Video Library

2015-08-20

This view from NASA Cassini spacecraft looks toward Saturn icy moon Dione, with giant Saturn and its rings in the background, just prior to the mission final close approach to the moon on August 17, 2015. At lower right is the large, multi-ringed impact basin named Evander, which is about 220 miles (350 kilometers) wide. The canyons of Padua Chasma, features that form part of Dione's bright, wispy terrain, reach into the darkness at left. Imaging scientists combined nine visible light (clear spectral filter) images to create this mosaic view: eight from the narrow-angle camera and one from the wide-angle camera, which fills in an area at lower left. The scene is an orthographic projection centered on terrain at 0.2 degrees north latitude, 179 degrees west longitude on Dione. An orthographic view is most like the view seen by a distant observer looking through a telescope. North on Dione is up. The view was acquired at distances ranging from approximately 106,000 miles (170,000 kilometers) to 39,000 miles (63,000 kilometers) from Dione and at a sun-Dione-spacecraft, or phase, angle of 35 degrees. Image scale is about 1,500 feet (450 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA19650

Happy Anniversary to a Galactic Explorer

NASA Image and Video Library

2004-05-24

The Galaxy Evolution Explorer specializes in surveying galaxies in ultraviolet light. Its telescope, 50 centimeters (19.7 inches) in diameter, has a field of view that is much wider than most ground-based and space-based telescopes. This field of view, nearly three times the diameter of the Moon, allowed the Galaxy Evolution Explorer to discover seemingly newborn galaxies in our local universe. The telescope surveyed thousands of galaxies before finding three-dozen of these newborns. http://photojournal.jpl.nasa.gov/catalog/PIA05979

Perceptual Calibration for Immersive Display Environments

PubMed Central

Ponto, Kevin; Gleicher, Michael; Radwin, Robert G.; Shin, Hyun Joon

2013-01-01

The perception of objects, depth, and distance has been repeatedly shown to be divergent between virtual and physical environments. We hypothesize that many of these discrepancies stem from incorrect geometric viewing parameters, specifically that physical measurements of eye position are insufficiently precise to provide proper viewing parameters. In this paper, we introduce a perceptual calibration procedure derived from geometric models. While most research has used geometric models to predict perceptual errors, we instead use these models inversely to determine perceptually correct viewing parameters. We study the advantages of these new psychophysically determined viewing parameters compared to the commonly used measured viewing parameters in an experiment with 20 subjects. The perceptually calibrated viewing parameters for the subjects generally produced new virtual eye positions that were wider and deeper than standard practices would estimate. Our study shows that perceptually calibrated viewing parameters can significantly improve depth acuity, distance estimation, and the perception of shape. PMID:23428454

The extreme blazar AO 0235+164 as seen by extensive ground and space radio observations

NASA Astrophysics Data System (ADS)

Kutkin, A. M.; Pashchenko, I. N.; Lisakov, M. M.; Voytsik, P. A.; Sokolovsky, K. V.; Kovalev, Y. Y.; Lobanov, A. P.; Ipatov, A. V.; Aller, M. F.; Aller, H. D.; Lahteenmaki, A.; Tornikoski, M.; Gurvits, L. I.

2018-04-01

Clues to the physical conditions in radio cores of blazars come from measurements of brightness temperatures as well as effects produced by intrinsic opacity. We study the properties of the ultra-compact blazar AO 0235+164 with RadioAstron ground-space radio interferometer, multifrequency VLBA, EVN, and single-dish radio observations. We employ visibility modelling and image stacking for deriving structure and kinematics of the source, and use Gaussian process regression to find the relative multiband time delays of the flares. The multifrequency core size and time lags support prevailing synchrotron self-absorption. The intrinsic brightness temperature of the core derived from ground-based very long baseline interferometry (VLBI) is close to the equipartition regime value. In the same time, there is evidence for ultra-compact features of the size of less than 10 μas in the source, which might be responsible for the extreme apparent brightness temperatures of up to 1014 K as measured by RadioAstron. In 2007-2016 the VLBI components in the source at 43 GHz are found predominantly in two directions, suggesting a bend of the outflow from southern to northern direction. The apparent opening angle of the jet seen in the stacked image at 43 GHz is two times wider than that at 15 GHz, indicating a collimation of the flow within the central 1.5 mas. We estimate the Lorentz factor Γ = 14, the Doppler factor δ = 21, and the viewing angle θ = 1.7° of the apparent jet base, derive the gradients of magnetic field strength and electron density in the outflow, and the distance between jet apex and the core at each frequency.

Curiosity Rover View of Alluring Martian Geology Ahead

NASA Image and Video Library

2015-08-05

A southward-looking panorama combining images from both cameras of the Mast Camera Mastcam instrument on NASA Curiosity Mars Rover shows diverse geological textures on Mount Sharp. A southward-looking panorama combining images from both cameras of the Mast Camera (Mastcam) instrument on NASA's Curiosity Mars Rover shows diverse geological textures on Mount Sharp. Three years after landing on Mars, the mission is investigating this layered mountain for evidence about changes in Martian environmental conditions, from an ancient time when conditions were favorable for microbial life to the much-drier present. Gravel and sand ripples fill the foreground, typical of terrains that Curiosity traversed to reach Mount Sharp from its landing site. Outcrops in the midfield are of two types: dust-covered, smooth bedrock that forms the base of the mountain, and sandstone ridges that shed boulders as they erode. Rounded buttes in the distance contain sulfate minerals, perhaps indicating a change in the availability of water when they formed. Some of the layering patterns on higher levels of Mount Sharp in the background are tilted at different angles than others, evidence of complicated relationships still to be deciphered. The scene spans from southeastward at left to southwestward at right. The component images were taken on April 10 and 11, 2015, the 952nd and 953rd Martian days (or sols) since the rover's landing on Mars on Aug. 6, 2012, UTC (Aug. 5, PDT). Images in the central part of the panorama are from Mastcam's right-eye camera, which is equipped with a 100-millimeter-focal-length telephoto lens. Images used in outer portions, including the most distant portions of the mountain in the scene, were taken with Mastcam's left-eye camera, using a wider-angle, 34-millimeter lens. http://photojournal.jpl.nasa.gov/catalog/PIA19803

Perceived orientation, spatial layout and the geometry of pictures

NASA Technical Reports Server (NTRS)

Goldstein, E. Bruce

1989-01-01

The purpose is to discuss the role of geometry in determining the perception of spatial layout and perceived orientation in pictures viewed at an angle. This discussion derives from Cutting's (1988) suggestion, based on his analysis of some of the author's data (Goldstein, 1987), that the changes in perceived orientation that occur when pictures are viewed at an angle can be explained in terms of geometrically produced changes in the picture's virtual space.

Variation in spectral response of soybeans with respect to illumination, view, and canopy geometry

NASA Technical Reports Server (NTRS)

Ranson, K. J.; Biehl, L. L.; Bauer, M. E.

1984-01-01

Comparisons of the spectral response for incomplete (well-defined row structure) and complete (overlapping row structure) canopies of soybeans indicated a greater dependence on Sun and view geometry for the incomplete canopies. Red and near-IR reflectance for the incomplete canopy decreased as solar zenith angle increased for a nadir view angle until the soil between the plant rows was completely shaded. Thereafter for increasing solar zenith angle, the red reflectance leveled off and the near-IR reflectance increased. A 'hot spot' effect was evident for the red and near-IR reflectance factors. The 'hot spot' effect was more pronounced for the red band based on relative reflectance value changes. The ratios of off-nadir to nadir acquired data reveal that off-nadir red band reflectance factors more closely approximated straightdown measurements for time periods away from solar noon. Normalized difference generally approximated straightdown measurements during the middle portion of the day.

Effect of structured visual environments on apparent eye level.

PubMed

Stoper, A E; Cohen, M M

1989-11-01

Each of 12 subjects set a binocularly viewed target to apparent eye level; the target was projected on the rear wall of an open box, the floor of which was horizontal or pitched up and down at angles of 7.5 degrees and 15 degrees. Settings of the target were systematically biased by 60% of the pitch angle when the interior of the box was illuminated, but by only 5% when the interior of the box was darkened. Within-subjects variability of the settings was less under illuminated viewing conditions than in the dark, but was independent of box pitch angle. In a second experiment, 11 subjects were tested with an illuminated pitched box, yielding biases of 53% and 49% for binocular and monocular viewing conditions, respectively. The results are discussed in terms of individual and interactive effects of optical, gravitational, and extraretinal eye-position information in determining judgements of eye level.

Image quality improvement in MDCT cardiac imaging via SMART-RECON method

NASA Astrophysics Data System (ADS)

Li, Yinsheng; Cao, Ximiao; Xing, Zhanfeng; Sun, Xuguang; Hsieh, Jiang; Chen, Guang-Hong

2017-03-01

Coronary CT angiography (CCTA) is a challenging imaging task currently limited by the achievable temporal resolution of modern Multi-Detector CT (MDCT) scanners. In this paper, the recently proposed SMARTRECON method has been applied in MDCT-based CCTA imaging to improve the image quality without any prior knowledge of cardiac motion. After the prospective ECG-gated data acquisition from a short-scan angular span, the acquired data were sorted into several sub-sectors of view angles; each corresponds to a 1/4th of the short-scan angular range. Information of the cardiac motion was thus encoded into the data in each view angle sub-sector. The SMART-RECON algorithm was then applied to jointly reconstruct several image volumes, each of which is temporally consistent with the data acquired in the corresponding view angle sub-sector. Extensive numerical simulations were performed to validate the proposed technique and investigate the performance dependence.

Soybean canopy reflectance as a function of view and illumination geometry

NASA Technical Reports Server (NTRS)

Ranson, K. J.; Vanderbilt, V. C.; Biehl, L. L.; Robinson, B. F.; Bauer, M. E.

1981-01-01

Reflectances were calculated from measurements at four wavelength bands through eight view azimuth and seven view zenith directions, for various solar zenith and azimuth angles over portions of three days, in an experimental characterization of a soybean field by means of its reflectances and physical and agronomic attributes. Results indicate that the distribution of reflectance from a soybean field is a function of the solar illumination and viewing geometry, wavelength, and row direction, as well as the state of canopy development. Shadows between rows were found to affect visible wavelength band reflectance to a greater extent than near-IR reflectance. A model describing reflectance variation as a function of projected solar and viewing angles is proposed, which approximates the visible wavelength band reflectance variations of a canopy with a well-defined row structure.

The Wider View

ERIC Educational Resources Information Center

Lawrence, Liz

2010-01-01

In this article, the author talks about Primary Science Committee's (PSC) joint meeting with members of the Scottish Primary Group in Edinburgh. The remit of the group is to advise on primary matters, develop primary aspects of Scottish Region's Annual Conference and run primary-focused continuing professional development (CPD) events as part of…

Culture vs. Technology: Mass Media Policy of the Netherlands Attempts a Balance.

ERIC Educational Resources Information Center

Heuterman, Thomas H.; Rennen, Toon

Telecommunications policy makers in Western Europe face the dilema of satisfying public demand for a wider range of television viewing alternatives without sacrificing national cultural integrity. The Dutch Parliament addressed this problem in 1984, 1985, and 1986 as it approved steps to implement the "Medianota," the comprehensive…

Orwell on Language and Politics.

ERIC Educational Resources Information Center

Joseph, John E.

2000-01-01

Newspeak, the engineered language of George Orwell's novel "Nineteen Eighty-Four," is discussed in the context of Orwell's wider views on language and politics and the need for linguistic intervention as part of the struggle against tyranny, and the related or opposed ideas of some of Orwell's contemporaries and Saussure. Orwell worried…

Institutional Level Student Engagement and Organisational Cultures

ERIC Educational Resources Information Center

van der Velden, Gwen

2012-01-01

Driven by the growing presence of market forces within higher education worldwide, universities are changing the way they engage with students. This article explores how a university's internal culture relates to engagement with students and their views. It builds on wider research into student engagement and organisational cultures. The…

Video Views and Reviews

ERIC Educational Resources Information Center

Watters, Christopher

2003-01-01

These days, all introductory biology students know that sliding filaments of myosin and actin cause muscle contraction. Moreover, cell biology students learn that there are more ubiquitous, less specialized forms of cell motility than what is evident in contracting muscle cells. Increasingly, it seems that actin is involved in a wider variety of…

Complicating "Student Behaviour": Exploring the Discursive Constitution of "Learner Subjectivities"

ERIC Educational Resources Information Center

Millei, Zsuzsa; Petersen, Eva Bendix

2015-01-01

When educators consider "student behaviour", they usually think about "problem behaviour" such as disruption or defiance. This limited and limiting view of "student behaviour" not only fails to acknowledge children as educational actors in a wider sense, but also narrowly positions educators as either in control or…

"YOUR VIEWS SHOWED TRUE IGNORANCE!!!": (Mis)Communication in an Online Interracial Discussion Forum.

ERIC Educational Resources Information Center

McKee, Heidi

2002-01-01

Focuses on the dynamics of interracial electronic communication. Examines the misunderstandings that arose in this interracial discussion, situating the causes and consequences of the students' discourse within both the local context of the electronic forum and within wider cultural patterns. Suggests strategies for facilitating more productive…

64. VIEW FROM THE NORTHEAST IN THE NORTHEAST QUADRANT. DETAIL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

64. VIEW FROM THE NORTHEAST IN THE NORTHEAST QUADRANT. DETAIL VIEW OF THE RIGHT FACE. A PORTION OF THE RIGHT SHOULDER ANGLE IS INCLUDED ON THE LEFT-SIDE OF THE IMAGE, WITH SCALE. - Fort Sumter, Charleston, Charleston County, SC

Access to dental care and dental ill-health of people with serious mental illness: views of nurses working in mental health settings in Australia.

PubMed

Happell, Brenda; Platania-Phung, Chris; Scott, David; Hanley, Christine

2015-01-01

People with serious mental illness experience higher rates of oral and dental health problems than the wider population. Little is known about how dental health is viewed or addressed by nurses working with mental health consumers. This paper presents the views of nurses regarding the nature and severity of dental health problems of consumers with serious mental illness, and how often they provide advice on dental health. Mental health sector nurses (n=643) completed an online survey, including questions on dental and oral health issues of people with serious mental illness. The majority of nurses considered the oral and dental conditions of people with serious mental illness to be worse than the wider community. When compared with a range of significant physical health issues (e.g. cardiovascular disease), many nurses emphasised that dental and oral problems are one of the most salient health issues facing people with serious mental illness, their level of access to dental care services is severely inadequate and they suffer significantly worse dental health outcomes as a result. This study highlights the need for reforms to increase access to dental and oral health care for mental health consumers.

Touch-screen tablet user configurations and case-supported tilt affect head and neck flexion angles.

PubMed

Young, Justin G; Trudeau, Matthieu; Odell, Dan; Marinelli, Kim; Dennerlein, Jack T

2012-01-01

The aim of this study was to determine how head and neck postures vary when using two media tablet (slate) computers in four common user configurations. Fifteen experienced media tablet users completed a set of simulated tasks with two media tablets in four typical user configurations. The four configurations were: on the lap and held with the user's hands, on the lap and in a case, on a table and in a case, and on a table and in a case set at a high angle for watching movies. An infra-red LED marker based motion analysis system measured head/neck postures. Head and neck flexion significantly varied across the four configurations and across the two tablets tested. Head and neck flexion angles during tablet use were greater, in general, than angles previously reported for desktop and notebook computing. Postural differences between tablets were driven by case designs, which provided significantly different tilt angles, while postural differences between configurations were driven by gaze and viewing angles. Head and neck posture during tablet computing can be improved by placing the tablet higher to avoid low gaze angles (i.e. on a table rather than on the lap) and through the use of a case that provides optimal viewing angles.

Changing paradigms in radiobiology.

PubMed

Mothersill, Carmel; Seymour, Colin

2012-01-01

The last 25 years have seen a major shift in emphasis in the field of radiobiology from a DNA-centric view of how radiation damage occurs to a much more biological view that appreciates the importance of macro-and micro-environments, hierarchical organization, underlying genetics, evolution, adaptation and signaling at all levels from atoms to ecosystems. The new view incorporates concepts of hormesis, nonlinear systems, bioenergy field theory, uncertainty and homeodynamics. While the mechanisms underlying these effects and responses are still far from clear, it is very apparent that their implications are much wider than the field of radiobiology. This reflection discusses the changing views and considers how they are influencing thought in environmental and medical science and systems biology. Copyright © 2012 Elsevier B.V. All rights reserved.

High Efficiency Large-Angle Pancharatnam Phase Deflector Based on Dual Twist Design

DTIC Science & Technology

2016-12-16

previous approaches have been reported, with an even wider range of potential applications8-13. Figure 1a shows the schematics of a thin- film beam...using a liquid crystal device. SID Symp. Dig. Tech. Papers 45, 739–742 (2014). 10. Gao, K., Cheng, H. H., Bhowmik, A. K. & Bos, P. J. Thin- film ...efficient thin- film polarizing beamsplitters for broadband light. Proc. SPIE 6682, 668211 (2007). Acknowledgements We express thanks for financial

Bony Pelvis Dimensions in Women With and Without Stress Urinary Incontinence

PubMed Central

Berger, Mitchell B.; Doumouchtsis, Stergios K.; DeLancey, John O.

2012-01-01

AIMS To test the null hypothesis that bony pelvis dimensions are similar in women with and without stress urinary incontinence, both in the postpartum and midlife periods. METHODS Secondary analyses were performed of two case-control studies comparing women with stress urinary incontinence to asymptomatic controls. One study examined primiparas in the first 9–12 months postpartum; the other study involved middle-aged women. Stress urinary incontinence was confirmed by full-bladder stress test. All subjects underwent pelvic magnetic resonance imaging. The interspinous and intertuberous diameters, subpubic angle and sacrococcygeal joint-to-the inferior pubic point distance were measured from the images independently by two authors. RESULTS In the young cohorts, we compared primiparas with de novo postpartum stress urinary incontinence to both continent primiparas and nulliparas. Postpartum stress urinary incontinence is associated with a wider subpubic angle. There is also a trend towards wider interspinous and intertuberous diameters in the stress-incontinent primiparas as compared to the continent cohorts, although this did not reach statistical significance with our sample sizes. By contrast, no significant differences in bony pelvis dimensions were identified when comparing middle-aged women with stress urinary incontinence and their continent controls. CONCLUSIONS Bony pelvis dimensions are different in women with stress urinary incontinence than in matched continent controls. However, these differences are only identified in young primiparas in the postpartum period, not in middle-aged women. PMID:22674676

Photographic measurement of head and cervical posture when viewing mobile phone: a pilot study.

PubMed

Guan, Xiaofei; Fan, Guoxin; Wu, Xinbo; Zeng, Ying; Su, Hang; Gu, Guangfei; Zhou, Qi; Gu, Xin; Zhang, Hailong; He, Shisheng

2015-12-01

With the dramatic growth of mobile phone usage, concerns have been raised with regard to the adverse health effects of mobile phone on spinal posture. The aim of this study was to determine the head and cervical postures by photogrammetry when viewing the mobile phone screen, compared with those in neutral standing posture. A total of 186 subjects (81 females and 105 males) aged from 17 to 31 years old participated in this study. Subjects were instructed to stand neutrally and using mobile phone as in daily life. Using a photographic method, the sagittal head and cervical postures were assessed by head tilt angle, neck tilt angle, forward head shift and gaze angle. The photographic method showed a high intra-rater and inter-rater reliability in measuring the sagittal posture of cervical spine and gaze angle (ICCs ranged from 0.80 to 0.99). When looking at mobile phone, the head tilt angle significantly increased (from 74.55° to 95.22°, p = 0.000) and the neck angle decreased (from 54.68° to 38.77°, p = 0.000). The forward head posture was also confirmed by the significantly increased head shift (from 10.90 to 13.85 cm, p = 0.000). The posture assumed in mobile phone use was significantly correlated with neutral posture (p < 0.05). Males displayed a more forward head posture than females (p < 0.05). The head tilt angle was positively correlated with the gaze angle (r = 0.616, p = 0.000), while the neck tilt angle was negatively correlated with the gaze angle (r = -0.628, p = 0.000). Photogrammetry is a reliable, quantitative method to evaluate the head and cervical posture during mobile phone use. Compared to neutral standing, subjects display a more forward head posture when viewing the mobile phone screen, which is correlated with neutral posture, gaze angle and gender. Future studies will be needed to investigate a dose-response relationship between mobile phone use and assumed posture.

Wide-angle Optical Telescope for the EUSO Experiments

NASA Technical Reports Server (NTRS)

Hillman, L. W.; Takahaski, Y.; Zuccaro, A.; Lamb, D.; Pitalo, K.; Lopado, A.; Keys, A.

2003-01-01

Future spacebased air shower experiments, including the planned Extreme Universe Space Observatory (EUSO) mission, require a wide-angle telescope in the near-UV wavelengths 330 - 400 nm. Widest possible target aperture of earth's atmosphere, such as greater than 10(exp 5) square kilometers sr, can be viewed within the field-of-view of 30 degrees from space. EUSO's optical design is required to be compact, being constrained by the allocated mass and diameter for use in space. Two doublesided Fresnel lenses with 2.5-m diameter are chosen for the baseline design. It satisfies the imaging resolution of 0.1 degree over the 30-degree field of view.

Improved estimation of leaf area index and leaf chlorophyll content of a potato crop using multi-angle spectral data - potential of unmanned aerial vehicle imagery

NASA Astrophysics Data System (ADS)

Roosjen, Peter P. J.; Brede, Benjamin; Suomalainen, Juha M.; Bartholomeus, Harm M.; Kooistra, Lammert; Clevers, Jan G. P. W.

2018-04-01

In addition to single-angle reflectance data, multi-angular observations can be used as an additional information source for the retrieval of properties of an observed target surface. In this paper, we studied the potential of multi-angular reflectance data for the improvement of leaf area index (LAI) and leaf chlorophyll content (LCC) estimation by numerical inversion of the PROSAIL model. The potential for improvement of LAI and LCC was evaluated for both measured data and simulated data. The measured data was collected on 19 July 2016 by a frame-camera mounted on an unmanned aerial vehicle (UAV) over a potato field, where eight experimental plots of 30 × 30 m were designed with different fertilization levels. Dozens of viewing angles, covering the hemisphere up to around 30° from nadir, were obtained by a large forward and sideways overlap of collected images. Simultaneously to the UAV flight, in situ measurements of LAI and LCC were performed. Inversion of the PROSAIL model was done based on nadir data and based on multi-angular data collected by the UAV. Inversion based on the multi-angular data performed slightly better than inversion based on nadir data, indicated by the decrease in RMSE from 0.70 to 0.65 m2/m2 for the estimation of LAI, and from 17.35 to 17.29 μg/cm2 for the estimation of LCC, when nadir data were used and when multi-angular data were used, respectively. In addition to inversions based on measured data, we simulated several datasets at different multi-angular configurations and compared the accuracy of the inversions of these datasets with the inversion based on data simulated at nadir position. In general, the results based on simulated (synthetic) data indicated that when more viewing angles, more well distributed viewing angles, and viewing angles up to larger zenith angles were available for inversion, the most accurate estimations were obtained. Interestingly, when using spectra simulated at multi-angular sampling configurations as were captured by the UAV platform (view zenith angles up to 30°), already a huge improvement could be obtained when compared to solely using spectra simulated at nadir position. The results of this study show that the estimation of LAI and LCC by numerical inversion of the PROSAIL model can be improved when multi-angular observations are introduced. However, for the potato crop, PROSAIL inversion for measured data only showed moderate accuracy and slight improvements.

Calibrators measurement system for headlamp tester of motor vehicle base on machine vision

NASA Astrophysics Data System (ADS)

Pan, Yue; Zhang, Fan; Xu, Xi-ping; Zheng, Zhe

2014-09-01

With the development of photoelectric detection technology, machine vision has a wider use in the field of industry. The paper mainly introduces auto lamps tester calibrator measuring system, of which CCD image sampling system is the core. Also, it shows the measuring principle of optical axial angle and light intensity, and proves the linear relationship between calibrator's facula illumination and image plane illumination. The paper provides an important specification of CCD imaging system. Image processing by MATLAB can get flare's geometric midpoint and average gray level. By fitting the statistics via the method of the least square, we can get regression equation of illumination and gray level. It analyzes the error of experimental result of measurement system, and gives the standard uncertainty of synthesis and the resource of optical axial angle. Optical axial angle's average measuring accuracy is controlled within 40''. The whole testing process uses digital means instead of artificial factors, which has higher accuracy, more repeatability and better mentality than any other measuring systems.

Pixel-level tunable liquid crystal lenses for auto-stereoscopic display

NASA Astrophysics Data System (ADS)

Li, Kun; Robertson, Brian; Pivnenko, Mike; Chu, Daping; Zhou, Jiong; Yao, Jun

2014-02-01

Mobile video and gaming are now widely used, and delivery of a glass-free 3D experience is of both research and development interest. The key drawbacks of a conventional 3D display based on a static lenticular lenslet array and parallax barriers are low resolution, limited viewing angle and reduced brightness, mainly because of the need of multiple-pixels for each object point. This study describes the concept and performance of pixel-level cylindrical liquid crystal (LC) lenses, which are designed to steer light to the left and right eye sequentially to form stereo parallax. The width of the LC lenses can be as small as 20-30 μm, so that the associated auto-stereoscopic display will have the same resolution as the 2D display panel in use. Such a thin sheet of tunable LC lens array can be applied directly on existing mobile displays, and can deliver 3D viewing experience while maintaining 2D viewing capability. Transparent electrodes were laser patterned to achieve the single pixel lens resolution, and a high birefringent LC material was used to realise a large diffraction angle for a wide field of view. Simulation was carried out to model the intensity profile at the viewing plane and optimise the lens array based on the measured LC phase profile. The measured viewing angle and intensity profile were compared with the simulation results.

Changes in Anterior Segment Morphology and Predictors of Angle Widening after Laser Iridotomy in South Indian Eyes.

PubMed

Zebardast, Nazlee; Kavitha, Srinivasan; Krishnamurthy, Palaniswamy; Friedman, David S; Nongpiur, Monisha E; Aung, Tin; Quigley, Harry A; Ramulu, Pradeep Y; Venkatesh, Rengaraj

2016-12-01

To compare anterior segment optical coherence tomography (ASOCT) angle morphology before and after laser peripheral iridotomy (LPI) in a cohort of South Indian subjects with primary angle-closure suspect (PACS) or primary angle-closure/primary angle-closure glaucoma (PAC/PACG) and to examine baseline parameters associated with angle widening. Prospective observational study. A total of 244 subjects aged ≥30 years with PACS or PAC/PACG in at least 1 eye. The ASOCT images and angle gonioscopic grades were analyzed for all subjects at baseline and 2 weeks after LPI. Multivariable linear and logistic regression models were used to determine predictors of angle widening (change in mean angle opening distance [AOD750]) and angle opening (all 4 quadrants with trabecular meshwork [TM] visible on gonioscopy after LPI). Change in ASOCT parameters with LPI and baseline predictors of angle widening. Laser peripheral iridotomy resulted in angle widening on ASOCT with significant increases in AOD750, angle recess area, and trabecular iris surface area (P < 0.05 for all). Gonioscopically, 44.7% of all subjects had open angles in all 4 quadrants after LPI, with a greater percentage of angles open in the PACS group compared with the PAC/PACG group (52.4% vs. 36.4%; P = 0.01). In multivariable regression analyses, greater postoperative angle widening as defined by change in AOD750 was associated with shorter baseline AOD750 and axial length, and greater baseline anterior chamber depth, iris curvature, and lens vault (P ≤ 0.002 for all). Gonioscopic angle opening after LPI was more common with wider baseline angle width (modified Shaffer grade) and lower cup-to-disc ratio (P < 0.001 for both). In a South Indian population with PACS or PAC/PACG, LPI results in significant anterior chamber angle widening seen on both ASOCT and gonioscopy, although some degree of persistent iridotrabecular contact was present in approximately half of PACS eyes and approximately two thirds of PAC/PACG eyes on gonioscopy. The greatest widening by ASOCT was observed in eyes with features most consistent with greater baseline pupillary block. Copyright © 2016 American Academy of Ophthalmology. All rights reserved.

Holographic elements and curved slit used to enlarge field of view in rocket detection system

NASA Astrophysics Data System (ADS)

Breton, Mélanie; Fortin, Jean; Lessard, Roger A.; Châteauneuf, Marc

2006-09-01

Rocket detection over a wide field of view is an important issue in the protection of light armored vehicle. Traditionally, the detection occurs in UV band, but recent studies have shown the existence of significant emission peaks in the visible and near infrared at rocket launch time. The use of the visible region is interesting in order to reduce the weight and cost of systems. Current methods to detect those specific peaks involve use of interferometric filters. However, they fail to combine wide angle with wavelength selectivity. A linear array of volume holographic elements combined with a curved exit slit is proposed for the development of a wide field of view sensor for the detection of solid propellant motor launch flash. The sensor is envisaged to trigger an active protection system. On the basis of geometric theory, a system has been designed. It consists of a collector, a linear array of holographic elements, a curved slit and a detector. The collector is an off-axis parabolic mirror. Holographic elements are recorded subdividing a hologram film in regions, each individually exposed with a different incidence angle. All regions have a common diffraction angle. The incident angle determines the instantaneous field of view of the elements. The volume hologram performs the function of separating and focusing the diffracted beam on an image plane to achieve wavelength filtering. Conical diffraction property is used to enlarge the field of view in elevation. A curved slit was designed to correspond to oblique incidence of the holographic linear array. It is situated at the image plane and filters the diffracted spectrum toward the sensor. The field of view of the design was calculated to be 34 degrees. This was validated by a prototype tested during a field trial. Results are presented and analyzed. The system succeeded in detecting the rocket launch flash at desired fields of view.

Digital mammography: comparative performance of color LCD and monochrome CRT displays.

PubMed

Samei, Ehsan; Poolla, Ananth; Ulissey, Michael J; Lewin, John M

2007-05-01

To evaluate the comparative performance of high-fidelity liquid crystal display (LCD) and cathode ray tube (CRT) devices for mammography applications, and to assess the impact of LCD viewing angle on detection accuracy. Ninety 1 k x 1 k images were selected from a database of digital mammograms: 30 without any abnormality present, 30 with subtle masses, and 30 with subtle microcalcifications. The images were used with waived informed consent, Health Insurance Portability and Accountability Act compliance, and Institutional Review Board approval. With postprocessing presentation identical to those of the commercial mammography system used, 1 k x 1 k sections of images were viewed on a monochrome CRT and a color LCD in native grayscale, and with a grayscale representative of images viewed from a 30 degrees or 50 degrees off-normal viewing angle. Randomized images were independently scored by four experienced breast radiologists for the presence of lesions using a 0-100 grading scale. To compare diagnostic performance of the display modes, observer scores were analyzed using receiver operating characteristic (ROC) and analysis of variance. For masses and microcalcifications, the detection rate in terms of the area under the ROC curve (A(z)) showed a 2% increase and a 4% decrease from CRT to LCD, respectively. However, differences were not statistically significant (P > .05). The viewing angle data showed better microcalcification detection but lower mass detection at 30 degrees viewing orientation. The overall results varied notably from observer to observer yielding no statistically discernible trends across all observers, suggesting that within the 0-50 degrees viewing angle range and in a controlled observer experiment, the variation in the contrast response of the LCD has little or no impact on the detection of mammographic lesions. Although CRTs and LCDs differ in terms of angular response, resolution, noise, and color, these characteristics seem to have little influence on the detection of mammographic lesions. The results suggest comparable performance in clinical applications of the two devices.

Site selection and directional models of deserts used for ERBE validation targets

NASA Technical Reports Server (NTRS)

Staylor, W. F.

1986-01-01

Broadband shortwave and longwave radiance measurements obtained from the Nimbus 7 Earth Radiation Budget scanner were used to develop reflectance and emittance models for the Sahara, Gibson, and Saudi Deserts. These deserts will serve as in-flight validation targets for the Earth Radiation Budget Experiment being flown on the Earth Radiation Budget Satellite and two National Oceanic and Atmospheric Administration polar satellites. The directional reflectance model derived for the deserts was a function of the sum and product of the cosines of the solar and viewing zenith angles, and thus reciprocity existed between these zenith angles. The emittance model was related by a power law of the cosine of the viewing zenith angle.

Departing Dione

NASA Image and Video Library

2015-08-20

NASA Cassini spacecraft captured this parting view showing the rough and icy crescent of Saturn moon Dione following the spacecraft last close flyby of the moon on Aug. 17, 2015. Cassini obtained a similar crescent view in 2005 (see PIA07745). The earlier view has an image scale about four times higher, but does not show the moon's full crescent as this view does. Five visible light (clear spectral filter), narrow-angle camera images were combined to create this mosaic view. The scene is an orthographic projection centered on terrain at 0.4 degrees north latitude, 30.6 degrees west longitude on Dione. An orthographic view is most like the view seen by a distant observer looking through a telescope. The view was acquired at distances ranging from approximately 37,000 miles (59,000 kilometers) to 47,000 miles (75,000 kilometers) from Dione and at a sun-Dione-spacecraft, or phase, angle of 145 degrees. Image scale is about 1,300 feet (400 meters) per pixel. North on Dione is up and rotated 34 degrees to the right. http://photojournal.jpl.nasa.gov/catalog/PIA19649

India: Gujarat

Atmospheric Science Data Center

2013-04-16

... Gujarat), and in areas close to the earthquake epicenter.  Research uses the unique capabilities of the Multi-angle Imaging ... Indo-Pakistani border, which were not easily accessible to survey teams on the ground. Changes in reflection at different view angles ...

Spherical grating based x-ray Talbot interferometry.

PubMed

Cong, Wenxiang; Xi, Yan; Wang, Ge

2015-11-01

Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh-Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and improves both signal visibility and dose utilization for pre-clinical and clinical applications.

Spherical grating based x-ray Talbot interferometry

PubMed Central

Cong, Wenxiang; Xi, Yan; Wang, Ge

2015-01-01

Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and improves both signal visibility and dose utilization for pre-clinical and clinical applications. PMID:26520741

Spherical grating based x-ray Talbot interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cong, Wenxiang, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Xi, Yan, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Wang, Ge, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu

2015-11-15

Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme formore » a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and improves both signal visibility and dose utilization for pre-clinical and clinical applications.« less

Stabilizing detached Bridgman melt crystal growth: Model-based nonlinear feedback control

NASA Astrophysics Data System (ADS)

Yeckel, Andrew; Daoutidis, Prodromos; Derby, Jeffrey J.

2012-12-01

The dynamics and operability limits of a nonlinear-proportional-integral controller designed to stabilize detached vertical Bridgman crystal growth are studied. The manipulated variable is the pressure difference between upper and lower vapor spaces, and the controlled variable is the gap width at the triple-phase line. The controller consists of a model-based nonlinear component coupled with a standard proportional-integral controller. The nonlinear component is based on a capillary model of shape stability. Perturbations to gap width, pressure difference, wetting angle, and growth angle are studied under both shape stable and shape unstable conditions. The nonlinear-PI controller allows a wider operating range of gain than a standard PI controller used alone, is easier to tune, and eliminates solution multiplicity from closed-loop operation.

Unzip instabilities: Straight to oscillatory transitions in the cutting of thin polymer sheets

NASA Astrophysics Data System (ADS)

Reis, P. M.; Kumar, A.; Shattuck, M. D.; Roman, B.

2008-06-01

We report an experimental investigation of the cutting of a thin brittle polymer sheet with a blunt tool. It was recently shown that the fracture path becomes oscillatory when the tool is much wider than the sheet thickness. Here we uncover two novel transitions from straight to oscillatory fracture by varying either the tilt angle of the tool or the speed of cutting, respectively. We denote these by angle and speed unzip instabilities and analyze them by quantifying both the dynamics of the crack tip and the final shapes of the fracture paths. Moreover, for the speed unzip instability, the straight crack lip obtained at low speeds exhibits out-of-plane buckling undulations (as opposed to being flat above the instability threshold) suggesting a transition from ductile to brittle fracture.

CMEs in the Heliosphere: I. A Statistical Analysis of the Observational Properties of CMEs Detected in the Heliosphere from 2007 to 2017 by STEREO/HI-1

NASA Astrophysics Data System (ADS)

Harrison, R. A.; Davies, J. A.; Barnes, D.; Byrne, J. P.; Perry, C. H.; Bothmer, V.; Eastwood, J. P.; Gallagher, P. T.; Kilpua, E. K. J.; Möstl, C.; Rodriguez, L.; Rouillard, A. P.; Odstrčil, D.

2018-05-01

We present a statistical analysis of coronal mass ejections (CMEs) imaged by the Heliospheric Imager (HI) instruments on board NASA's twin-spacecraft STEREO mission between April 2007 and August 2017 for STEREO-A and between April 2007 and September 2014 for STEREO-B. The analysis exploits a catalogue that was generated within the FP7 HELCATS project. Here, we focus on the observational characteristics of CMEs imaged in the heliosphere by the inner (HI-1) cameras, while following papers will present analyses of CME propagation through the entire HI fields of view. More specifically, in this paper we present distributions of the basic observational parameters - namely occurrence frequency, central position angle (PA) and PA span - derived from nearly 2000 detections of CMEs in the heliosphere by HI-1 on STEREO-A or STEREO-B from the minimum between Solar Cycles 23 and 24 to the maximum of Cycle 24; STEREO-A analysis includes a further 158 CME detections from the descending phase of Cycle 24, by which time communication with STEREO-B had been lost. We compare heliospheric CME characteristics with properties of CMEs observed at coronal altitudes, and with sunspot number. As expected, heliospheric CME rates correlate with sunspot number, and are not inconsistent with coronal rates once instrumental factors/differences in cataloguing philosophy are considered. As well as being more abundant, heliospheric CMEs, like their coronal counterparts, tend to be wider during solar maximum. Our results confirm previous coronagraph analyses suggesting that CME launch sites do not simply migrate to higher latitudes with increasing solar activity. At solar minimum, CMEs tend to be launched from equatorial latitudes, while at maximum, CMEs appear to be launched over a much wider latitude range; this has implications for understanding the CME/solar source association. Our analysis provides some supporting evidence for the systematic dragging of CMEs to lower latitude as they propagate outwards.

Radiative albedo from a linearly fibered half-space

NASA Astrophysics Data System (ADS)

Grzesik, J. A.

2018-05-01

A growing acceptance of fiber-reinforced composite materials imparts some relevance to exploring the effects which a predominantly linear scattering lattice may have upon interior radiative transport. Indeed, a central feature of electromagnetic wave propagation within such a lattice, if sufficiently dilute, is ray confinement to cones whose half-angles are set by that between lattice and the incident ray. When such propagation is subordinated to a viewpoint of an unpolarized intensity transport, one arrives at a somewhat simplified variant of the Boltzmann equation with spherical scattering demoted to its cylindrical counterpart. With a view to initiating a hopefully wider discussion of such phenomena, we follow through in detail the half-space albedo problem. This is done first along canonical lines that harness the Wiener-Hopf technique, and then once more in a discrete ordinates setting via flux decomposition along the eigenbasis of the underlying attenuation/scattering matrix. Good agreement is seen to prevail. We further suggest that the Case singular eigenfunction apparatus could likewise be evolved here in close analogy to its original, spherical scattering model. A cursory contact with related problems in the astrophysical literature suggests, in addition, that the basic physical fidelity of our scalar radiative transfer equation (RTE) remains open to improvement by passage to a (4×1) Stokes vector, (4×4) matricial setting.

Liquid crystal displays with plastic substrates

NASA Astrophysics Data System (ADS)

Lueder, Ernst H.

1998-04-01

Plastic substrates for the cells of displays exhibit only 1/6 of the weight of glass substrates; they are virtually unbreakable; their flexibility allows the designer to give them a shape suppressing reflections, to realize a display board on a curved surface or meeting the requirements for an appealing styling; displays with plastics are thinner which provides a wider viewing angle. These features render them attractive for displays in portable systems such as mobile phones, pagers, smart cards, personal digital assistants (PDAs) and portable computers. Reflective displays are especially attractive as they don't need a back light. The most important requirements are the protection of plastics against gas permeation and chemical agents, the prevention of layers on plastics to crack or peel off when the plastic is bent and the development of low temperature thin film processes because the plastics, as a rule, only tolerate temperatures below 150 degrees Celsius. Bistable reflective FLC- and PSCT-displays with plastic substrates will be introduced. Special sputtered SiO2-orientation layers preserve the displayed information even if pressure or torsion is applied. MIM-addressed PDLC-displays require additional Al- or Ti-layers which provide the necessary ductility. Sputtered or PECVD-generated TFTs can be fabricated on plastics at temperatures below 150 degrees Celsius.

Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, W.S.; Rutledge, J.T.; Gardner, T.L.

1996-11-01

Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regionalmore » fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.« less

Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, W.S.; Rutledge, J.T.; Fairbanks, T.D.

1996-12-31

Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regionalmore » fracture trend. However, widths of the stimulated zones differed by a factor of live between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.« less

Painted Lines on an Ornament

NASA Image and Video Library

2013-12-23

The globe of Saturn, seen here in natural color, is reminiscent of a holiday ornament in this wide-angle view from NASA's Cassini spacecraft. The characteristic hexagonal shape of Saturn's northern jet stream, somewhat yellow here, is visible. At the pole lies a Saturnian version of a high-speed hurricane, eye and all. This view is centered on terrain at 75 degrees north latitude, 120 degrees west longitude. Images taken using red, green and blue spectral filters were combined to create this natural-color view. The images were taken with the Cassini spacecraft wide-angle camera on July 22, 2013. This view was acquired at a distance of approximately 611,000 miles (984,000 kilometers) from Saturn. Image scale is 51 miles (82 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA17175

The effect of internal fixation lamp on anterior chamber angle width measured by anterior segment optical coherence tomography.

PubMed

Nakamine, Sakari; Sakai, Hiroshi; Arakaki, Yoshikuni; Yonahara, Michiko; Kaiya, Tadayoshi

2018-01-01

To study the effect of the internal fixation lamp on anterior chamber width measured by anterior segment optical coherence tomography. In a prospective cross sectional observational study, consecutive 22 right eyes of 22 patients (4 men and 18 women) with suspected primary angle closure underwent swept source domain anterior segment optical coherence tomography (AS-OCT), (CASIA SS-1000, Tomey, Nagoya, Japan). Anterior chamber parameters of angle opening distance (AOD), trabecular-iris angle (TIA), angle recess area (ARA) at 500 or 750 µm from scleral spur and pupil diameter were measured by AS-OCT in a three-dimensional mode in 4 quadrants (superior, inferior, temporal and nasal) in dark room setting both with and without internal fixation lamp. Anterior segment parameters of AOD 500 in superior, inferior and temporal quadrants, AOD 750 at superior and nasal, TIA 500 at superior, and inferior and TIA 750 at superior and nasal, and ARA 500 or 750 at superior and inferior with internal fixation lamp were greater and the pupil diameter was significantly (all P < 0.05, paired t test) smaller than when measured without fixation lamp. Internal fixation lamp of the anterior segment OCT makes the pupil constrict and angle wider. When using AS-OCT with usual setting with internal fixation lamp on with eyes in which the anterior chamber angle is narrow but open, it is recommended that the internal fixation lamp be turned off to ensure a clear indication as to whether the angle is open or closed in the dark.

Smartphone-Guided Needle Angle Selection During CT-Guided Procedures.

PubMed

Xu, Sheng; Krishnasamy, Venkatesh; Levy, Elliot; Li, Ming; Tse, Zion Tsz Ho; Wood, Bradford John

2018-01-01

In CT-guided intervention, translation from a planned needle insertion angle to the actual insertion angle is estimated only with the physician's visuospatial abilities. An iPhone app was developed to reduce reliance on operator ability to estimate and reproduce angles. The iPhone app overlays the planned angle on the smartphone's camera display in real-time based on the smartphone's orientation. The needle's angle is selected by visually comparing the actual needle with the guideline in the display. If the smartphone's screen is perpendicular to the planned path, the smartphone shows the Bull's-Eye View mode, in which the angle is selected after the needle's hub overlaps the tip in the camera. In phantom studies, we evaluated the accuracies of the hardware, the Guideline mode, and the Bull's-Eye View mode and showed the app's clinical efficacy. A proof-of-concept clinical case was also performed. The hardware accuracy was 0.37° ± 0.27° (mean ± SD). The mean error and navigation time were 1.0° ± 0.9° and 8.7 ± 2.3 seconds for a senior radiologist with 25 years' experience and 1.5° ± 1.3° and 8.0 ± 1.6 seconds for a junior radiologist with 4 years' experience. The accuracy of the Bull's-Eye View mode was 2.9° ± 1.1°. Combined CT and smart-phone guidance was significantly more accurate than CT-only guidance for the first needle pass (p = 0.046), which led to a smaller final targeting error (mean distance from needle tip to target, 2.5 vs 7.9 mm). Mobile devices can be useful for guiding needle-based interventions. The hardware is low cost and widely available. The method is accurate, effective, and easy to implement.

Facial profile parameters and their relative influence on bilabial prominence and the perceptions of facial profile attractiveness: A novel approach

PubMed Central

Denize, Erin Stewart; McDonald, Fraser; Sherriff, Martyn

2014-01-01

Objective To evaluate the relative importance of bilabial prominence in relation to other facial profile parameters in a normal population. Methods Profile stimulus images of 38 individuals (28 female and 10 male; ages 19-25 years) were shown to an unrelated group of first-year students (n = 42; ages 18-24 years). The images were individually viewed on a 17-inch monitor. The observers received standardized instructions before viewing. A six-question questionnaire was completed using a Likert-type scale. The responses were analyzed by ordered logistic regression to identify associations between profile characteristics and observer preferences. The Bayesian Information Criterion was used to select variables that explained observer preferences most accurately. Results Nasal, bilabial, and chin prominences; the nasofrontal angle; and lip curls had the greatest effect on overall profile attractiveness perceptions. The lip-chin-throat angle and upper lip curl had the greatest effect on forehead prominence perceptions. The bilabial prominence, nasolabial angle (particularly the lower component), and mentolabial angle had the greatest effect on nasal prominence perceptions. The bilabial prominence, nasolabial angle, chin prominence, and submental length had the greatest effect on lip prominence perceptions. The bilabial prominence, nasolabial angle, mentolabial angle, and submental length had the greatest effect on chin prominence perceptions. Conclusions More prominent lips, within normal limits, may be considered more attractive in the profile view. Profile parameters have a greater influence on their neighboring aesthetic units but indirectly influence related profile parameters, endorsing the importance of achieving an aesthetic balance between relative prominences of all aesthetic units of the facial profile. PMID:25133133

The solid angle hidden in polyhedron gravitation formulations

NASA Astrophysics Data System (ADS)

Werner, Robert A.

2017-03-01

Formulas of a homogeneous polyhedron's gravitational potential typically include two arctangent terms for every edge of every face and a special term to eliminate a possible facial singularity. However, the arctangent and singularity terms are equivalent to the face's solid angle viewed from the field point. A face's solid angle can be evaluated with a single arctangent, saving computation.

Prediction of the Aerodynamic Characteristics of Cruciform Missiles Including Effects of Roll Angle and Control Deflection

DTIC Science & Technology

1986-08-01

CHARACTERISTICS OF CRU.CIFORM MISSILES INCLUDING EFFECTS OF ROLL ANGLE AND CONTROL DEFLECTION N by Daniel J. Lesieutre Michael R. Mendenhall Susana M. Nazario...ANGLE AND CONTROL DEFLECTION Daniel J. Lesieutre Michael R. Mendenhal. Susana M. Nazario Nielsen Engineering & Research, Inc.00 Mountain View, CA 94043...Lo PREDICTION OF THE AERODYNAMIC CHARACTERISTICS OF CRU.CIFORM MISSILES - INCLUDING EFFECTS OF ROLL ANGLE AND CONTROL DEFLECTION by Daniel J

View Angle Effects on MODIS Snow Mapping in Forests

NASA Technical Reports Server (NTRS)

Xin, Qinchuan; Woodcock, Curtis E.; Liu, Jicheng; Tan, Bin; Melloh, Rae A.; Davis, Robert E.

2012-01-01

Binary snow maps and fractional snow cover data are provided routinely from MODIS (Moderate Resolution Imaging Spectroradiometer). This paper investigates how the wide observation angles of MODIS influence the current snow mapping algorithm in forested areas. Theoretical modeling results indicate that large view zenith angles (VZA) can lead to underestimation of fractional snow cover (FSC) by reducing the amount of the ground surface that is viewable through forest canopies, and by increasing uncertainties during the gridding of MODIS data. At the end of the MODIS scan line, the total modeled error can be as much as 50% for FSC. Empirical analysis of MODIS/Terra snow products in four forest sites shows high fluctuation in FSC estimates on consecutive days. In addition, the normalized difference snow index (NDSI) values, which are the primary input to the MODIS snow mapping algorithms, decrease as VZA increases at the site level. At the pixel level, NDSI values have higher variances, and are correlated with the normalized difference vegetation index (NDVI) in snow covered forests. These findings are consistent with our modeled results, and imply that consideration of view angle effects could improve MODIS snow monitoring in forested areas.

Astronomy in Denver: Polarization of bow shock nebulae around massive stars

NASA Astrophysics Data System (ADS)

Shrestha, Manisha; Hoffman, Jennifer L.; Ignace, Richard; Neilson, Hilding; Richard Ignace

2018-06-01

Stellar wind bow shocks are structures created when stellar winds with supersonic relative velocities interact with the local interstellar medium (ISM). They can be studied to understand the properties of stars as well as the ISM. Since bow shocks are asymmetric, light becomes polarized by scattering in the regions of enhanced density they create. We use a Monte Carlo radiative transfer code calle SLIP to simulate the polarization signatures produced by both resolved and unresolved bow shocks with analytically derived shapes and density structures. When electron scattering is the polarizing mechanism, we find that optical depth plays an important role in the polarization signatures. While results for low optical depths reproduce theoretical predictions, higher optical depths produce higher polarization and position angle rotations at specific viewing angles. This is due to the geometrical properties of the bow shock along with multiple scattering effects. For dust scattering, we find that the polarization signature is strongly affected by wavelength, dust size, dust composition, and viewing angle. Depending on the viewing angle, the polarization magnitude may increase or decrease as a function of wavelength. We will present results from these simulations and preliminary comparisons with observational data.

Study of the retardance of a birefringent waveplate at tilt incidence by Mueller matrix ellipsometer

NASA Astrophysics Data System (ADS)

Gu, Honggang; Chen, Xiuguo; Zhang, Chuanwei; Jiang, Hao; Liu, Shiyuan

2018-01-01

Birefringent waveplates are indispensable optical elements for polarization state modification in various optical systems. The retardance of a birefringent waveplate will change significantly when the incident angle of the light varies. Therefore, it is of great importance to study such field-of-view errors on the polarization properties, especially the retardance of a birefringent waveplate, for the performance improvement of the system. In this paper, we propose a generalized retardance formula at arbitrary incidence and azimuth for a general plane-parallel composite waveplate consisting of multiple aligned single waveplates. An efficient method and corresponding experimental set-up have been developed to characterize the retardance versus the field-of-view angle based on a constructed spectroscopic Mueller matrix ellipsometer. Both simulations and experiments on an MgF2 biplate over an incident angle of 0°-8° and an azimuthal angle of 0°-360° are presented as an example, and the dominant experimental errors are discussed and corrected. The experimental results strongly agree with the simulations with a maximum difference of 0.15° over the entire field of view, which indicates the validity and great potential of the presented method for birefringent waveplate characterization at tilt incidence.

Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

NASA Technical Reports Server (NTRS)

Pitone, D. S.; Klein, J. R.

1989-01-01

Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the large-angle pointing performance.

Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

NASA Technical Reports Server (NTRS)

Pitone, D. S.; Klein, J. R.; Twambly, B. J.

1990-01-01

Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X-ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the larg-angle pointing performance.

Multi-Angle View of the Canary Islands

NASA Technical Reports Server (NTRS)

2000-01-01

A multi-angle view of the Canary Islands in a dust storm, 29 February 2000. At left is a true-color image taken by the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. This image was captured by the MISR camera looking at a 70.5-degree angle to the surface, ahead of the spacecraft. The middle image was taken by the MISR downward-looking (nadir) camera, and the right image is from the aftward 70.5-degree camera. The images are reproduced using the same radiometric scale, so variations in brightness, color, and contrast represent true variations in surface and atmospheric reflectance with angle. Windblown dust from the Sahara Desert is apparent in all three images, and is much brighter in the oblique views. This illustrates how MISR's oblique imaging capability makes the instrument a sensitive detector of dust and other particles in the atmosphere. Data for all channels are presented in a Space Oblique Mercator map projection to facilitate their co-registration. The images are about 400 km (250 miles)wide, with a spatial resolution of about 1.1 kilometers (1,200 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Appalachian Mountains

Atmospheric Science Data Center

2014-05-15

...     View Larger Image Multi-angle views of the Appalachian Mountains, March 6, 2000 . ... Center Atmospheric Science Data Center in Hampton, VA. Photo credit: NASA/GSFC/LaRC/JPL, MISR Science Team Other formats ...

Eyjafjallajökull Ash Plume Particle Properties

NASA Image and Video Library

2010-04-21

As NASA Terra satellite flew over Iceland erupting Eyjafjallajökull volcano, its Multi-angle Imaging SpectroRadiometer instrument acquired 36 near-simultaneous images of the ash plume, covering nine view angles in each of four wavelengths.

An imaging anatomical study on percutaneous kyphoplasty for lumbar via a unilateral transverse process-pedicle approach.

PubMed

Wang, Song; Wang, Qing; Kang, Jianping; Xiu, Peng; Wang, Gaoju

2014-04-20

An imaging anatomical measurement. To investigate the anatomical feasibility of percutaneous kyphoplasty for lumbar osteoporotic vertebral compression fractures via a unilateral transverse process-pedicle approach (TPA). Kyphoplasty via a unilateral approach has been reported and good clinical results have been achieved. However, because of the lack of an anatomical study, these approaches have yet to be popularized. A total of 150 lumbar vertebral bodies of 30 patients were simulated kyphoplasty on the computed tomographic scans through conventional transpedicle approach (CTA) and the TPA, respectively. Anatomical parameters including the distance between the entry point and the midline of the vertebral body, the puncture inclination angle, and the success rate of puncture were measured and compared. The distance between the entry point and the midline from L1 to L5 lumbar levels varied from 20.6 ± 2.2 mm to 28.6 ± 2.9 mm in the CTA group and from 23.6 ± 2.2 mm to 33.6 ± 2.9 mm in the TPA group. The entry point from L1 to L5 in the TPA group was 3.0 ± 2.1 mm to 5.1 ± 2.7 mm more lateral than that in the CTA group. The medial inclination angles from L1 to L5 were 30.2° ± 6.4° to 47.7° ± 5.4° in the TPA and 15.3° ± 6.0° to 22.8° ± 8.7° in the CTA group. The inclination angles in the TPA group were greater than that in the CTA group and the safe range of the puncture angles was also wider. The success rate was 51.7% in the CTA group and 87.7% in the TPA group. The entry point through a TPA was localized at the midline of the transverse process, 3.0 to 5.1 mm outside the lateral margin of the pedicle projection. Compared with CTA, the puncture inclination angle in the TPA approach was much larger with a wider safe puncture range. The TPA approach allowed an easy puncture to meet or surpass the midline of the lumbar vertebral body. N/A.

Three paths toward the quantum angle operator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gazeau, Jean Pierre, E-mail: gazeau@apc.univ-paris7.fr; Szafraniec, Franciszek Hugon, E-mail: franciszek.szafraniec@uj.edu.pl

2016-12-15

We examine mathematical questions around angle (or phase) operator associated with a number operator through a short list of basic requirements. We implement three methods of construction of quantum angle. The first one is based on operator theory and parallels the definition of angle for the upper half-circle through its cosine and completed by a sign inversion. The two other methods are integral quantization generalizing in a certain sense the Berezin–Klauder approaches. One method pertains to Weyl–Heisenberg integral quantization of the plane viewed as the phase space of the motion on the line. It depends on a family of “weight”more » functions on the plane. The third method rests upon coherent state quantization of the cylinder viewed as the phase space of the motion on the circle. The construction of these coherent states depends on a family of probability distributions on the line.« less

Reproducing the hierarchy of disorder for Morpho-inspired, broad-angle color reflection

NASA Astrophysics Data System (ADS)

Song, Bokwang; Johansen, Villads Egede; Sigmund, Ole; Shin, Jung H.

2017-04-01

The scales of Morpho butterflies are covered with intricate, hierarchical ridge structures that produce a bright, blue reflection that remains stable across wide viewing angles. This effect has been researched extensively, and much understanding has been achieved using modeling that has focused on the positional disorder among the identical, multilayered ridges as the critical factor for producing angular independent color. Realizing such positional disorder of identical nanostructures is difficult, which in turn has limited experimental verification of different physical mechanisms that have been proposed. In this paper, we suggest an alternative model of inter-structural disorder that can achieve the same broad-angle color reflection, and is applicable to wafer-scale fabrication using conventional thin film technologies. Fabrication of a thin film that produces pure, stable blue across a viewing angle of more than 120 ° is demonstrated, together with a robust, conformal color coating.

Shuttle imaging radar views the Earth from Challenger: The SIR-B experiment

NASA Technical Reports Server (NTRS)

Ford, J. P.; Cimino, J. B.; Holt, B.; Ruzek, M. R.

1986-01-01

In October 1984, SIR-B obtained digital image data of about 6.5 million km2 of the Earth's surface. The coverage is mostly of selected experimental test sites located between latitudes 60 deg north and 60 deg south. Programmed adjustments made to the look angle of the steerable radar antenna and to the flight attitude of the shuttle during the mission permitted collection of multiple-incidence-angle coverage or extended mapping coverage as required for the experiments. The SIR-B images included here are representative of the coverage obtained for scientific studies in geology, cartography, hydrology, vegetation cover, and oceanography. The relations between radar backscatter and incidence angle for discriminating various types of surfaces, and the use of multiple-incidence-angle SIR-B images for stereo measurement and viewing, are illustrated with examples. Interpretation of the images is facilitated by corresponding images or photographs obtained by different sensors or by sketch maps or diagrams.

Description of a landing site indicator (LASI) for light aircraft operation

NASA Technical Reports Server (NTRS)

Fuller, H. V.; Outlaw, B. K. E.

1976-01-01

An experimental cockpit mounted head-up type display system was developed and evaluated by LaRC pilots during the landing phase of light aircraft operations. The Landing Site Indicator (LASI) system display consists of angle of attack, angle of sideslip, and indicated airspeed images superimposed on the pilot's view through the windshield. The information is made visible to the pilot by means of a partially reflective viewing screen which is suspended directly in frot of the pilot's eyes. Synchro transmitters are operated by vanes, located at the left wing tip, which sense angle of attack and sideslip angle. Information is presented near the center of the display in the form of a moving index on a fixed grid. The airspeed is sensed by a pitot-static pressure transducer and is presented in numerical form at the top center of the display.

Estimation of canopy carotenoid content of winter wheat using multi-angle hyperspectral data

NASA Astrophysics Data System (ADS)

Kong, Weiping; Huang, Wenjiang; Liu, Jiangui; Chen, Pengfei; Qin, Qiming; Ye, Huichun; Peng, Dailiang; Dong, Yingying; Mortimer, A. Hugh

2017-11-01

Precise estimation of carotenoid (Car) content in crops, using remote sensing data, could be helpful for agricultural resources management. Conventional methods for Car content estimation were mostly based on reflectance data acquired from nadir direction. However, reflectance acquired at this direction is highly influenced by canopy structure and soil background reflectance. Off-nadir observation is less impacted, and multi-angle viewing data are proven to contain additional information rarely exploited for crop Car content estimation. The objective of this study was to explore the potential of multi-angle observation data for winter wheat canopy Car content estimation. Canopy spectral reflectance was measured from nadir as well as from a series of off-nadir directions during different growing stages of winter wheat, with concurrent canopy Car content measurements. Correlation analyses were performed between Car content and the original and continuum removed spectral reflectance. Spectral features and previously published indices were derived from data obtained at different viewing angles and were tested for Car content estimation. Results showed that spectral features and indices obtained from backscattering directions between 20° and 40° view zenith angle had a stronger correlation with Car content than that from the nadir direction, and the strongest correlation was observed from about 30° backscattering direction. Spectral absorption depth at 500 nm derived from spectral data obtained from 30° backscattering direction was found to reduce the difference induced by plant cultivars greatly. It was the most suitable for winter wheat canopy Car estimation, with a coefficient of determination 0.79 and a root mean square error of 19.03 mg/m2. This work indicates the importance of taking viewing geometry effect into account when using spectral features/indices and provides new insight in the application of multi-angle remote sensing for the estimation of crop physiology.

Minimum viewing angle for visually guided ground speed control in bumblebees.

PubMed

Baird, Emily; Kornfeldt, Torill; Dacke, Marie

2010-05-01

To control flight, flying insects extract information from the pattern of visual motion generated during flight, known as optic flow. To regulate their ground speed, insects such as honeybees and Drosophila hold the rate of optic flow in the axial direction (front-to-back) constant. A consequence of this strategy is that its performance varies with the minimum viewing angle (the deviation from the frontal direction of the longitudinal axis of the insect) at which changes in axial optic flow are detected. The greater this angle, the later changes in the rate of optic flow, caused by changes in the density of the environment, will be detected. The aim of the present study is to examine the mechanisms of ground speed control in bumblebees and to identify the extent of the visual range over which optic flow for ground speed control is measured. Bumblebees were trained to fly through an experimental tunnel consisting of parallel vertical walls. Flights were recorded when (1) the distance between the tunnel walls was either 15 or 30 cm, (2) the visual texture on the tunnel walls provided either strong or weak optic flow cues and (3) the distance between the walls changed abruptly halfway along the tunnel's length. The results reveal that bumblebees regulate ground speed using optic flow cues and that changes in the rate of optic flow are detected at a minimum viewing angle of 23-30 deg., with a visual field that extends to approximately 155 deg. By measuring optic flow over a visual field that has a low minimum viewing angle, bumblebees are able to detect and respond to changes in the proximity of the environment well before they are encountered.

Teacher Misbehaviour: An Analysis of Disciplinary Orders by the General Teaching Council for England

ERIC Educational Resources Information Center

Page, Damien

2013-01-01

This article presents findings from a documentary analysis of 300 disciplinary orders against teachers from the General Teaching Council (GTC) for England. While the extant literature concerning teacher misbehaviour focuses primarily on pedagogical practice, this article draws on the wider organisational misbehaviour paradigm and views teachers as…

Let's Start Leveling about Leveling

ERIC Educational Resources Information Center

Glasswell, Kath; Ford, Michael

2011-01-01

In this article, the authors propose a revised way of thinking about reading levels, one that promotes a wider and more flexible view of teacher decision making about the use of leveled texts in classrooms. They share five key principles to consider when looking at the use of instruction that involves matching leveled materials with readers.…

Taking Account of Siblings--A View from Child Psychotherapy

ERIC Educational Resources Information Center

Rustin, Margaret

2007-01-01

This paper argues that siblinghood has had an important place in child psychotherapy thinking for many decades. Both psychoanalytic observation of young children and clinical experience have contributed to this. It discusses some reasons for the renewed interest in siblings in the wider psychoanalytic field and emphasises the existential threat to…

Stirring the Lions: Strategy and Tactics in Global Higher Education

ERIC Educational Resources Information Center

Robertson, Susan L.; Keeling, Ruth

2008-01-01

In many parts of the world, higher education is viewed as a prime "motor" for the development of a knowledge-based economy. Under the banner of this "new economy", higher education policies, programmes and practices have been increasingly co-opted and shaped by wider geo-strategic political and economic interests. This paper…

Education and Utopia: Robert Owen and Charles Fourier

ERIC Educational Resources Information Center

Leopold, David

2011-01-01

The aims of education, and the appropriate means of realising them, are a recurring preoccupation of utopian authors. The utopian socialists Robert Owen (1771-1858) and Charles Fourier (1772-1837) both place human nature at the core of their educational views, and both see education as central to their wider objective of social and political…

Classroom Behaviour Management: Educational Psychologists' Views on Effective Practice

ERIC Educational Resources Information Center

Hart, Robert

2010-01-01

The behaviour of children and young people in schools is a perennial concern to educators and the wider public alike. It also represents a significant focus for the work of educational psychologists (EPs). Research evidence has identified a number of strategies that teachers, students and school inspectors believe contribute to effective classroom…

Education for Global Citizenship in a Divided Society? Young People's Views and Experiences

ERIC Educational Resources Information Center

Niens, Ulrike; Reilly, Jacqueline

2012-01-01

Global citizenship education has been suggested as a means of overcoming the limitations of national citizenship in an increasingly globalised world. In divided societies, global citizenship education is especially relevant and problematic as it offers the opportunity to explore identities and conflict in a wider context. This paper therefore…

Characterization of lipid films by an angle-interrogation surface plasmon resonance imaging device.

PubMed

Liu, Linlin; Wang, Qiong; Yang, Zhong; Wang, Wangang; Hu, Ning; Luo, Hongyan; Liao, Yanjian; Zheng, Xiaolin; Yang, Jun

2015-04-01

Surface topographies of lipid films have an important significance in the analysis of the preparation of giant unilamellar vesicles (GUVs). In order to achieve accurately high-throughput and rapidly analysis of surface topographies of lipid films, a homemade SPR imaging device is constructed based on the classical Kretschmann configuration and an angle interrogation manner. A mathematical model is developed to accurately describe the shift including the light path in different conditions and the change of the illumination point on the CCD camera, and thus a SPR curve for each sampling point can also be achieved, based on this calculation method. The experiment results show that the topographies of lipid films formed in distinct experimental conditions can be accurately characterized, and the measuring resolution of the thickness lipid film may reach 0.05 nm. Compared with existing SPRi devices, which realize detection by monitoring the change of the reflective-light intensity, this new SPRi system can achieve the change of the resonance angle on the entire sensing surface. Thus, it has higher detection accuracy as the traditional angle-interrogation SPR sensor, with much wider detectable range of refractive index. Copyright © 2015 Elsevier B.V. All rights reserved.

Precise time dissemination and applications development on the Bonneville Power Administration system

NASA Technical Reports Server (NTRS)

Martin, Ken E.; Esztergalyos, J.

1992-01-01

The Bonneville Power Administration (BPA) uses IRIG-B transmitted over microwave as its primary system time dissemination. Problems with accuracy and reliability have led to ongoing research into better methods. BPA has also developed and deployed a unique fault locator which uses precise clocks synchronized by a pulse over microwaves. It automatically transmits the data to a central computer for analysis. A proposed system could combine fault location timing and time dissemination into a Global Position System (GPS) timing receiver and close the verification loop through a master station at the Dittmer Control Center. Such a system would have many advantages, including lower cost, higher reliability, and wider industry support. Test results indicate the GPS has sufficient accuracy and reliability for this and other current timing requirements including synchronous phase angle measurements. A phasor measurement system which provides phase angle has recently been tested with excellent results. Phase angle is a key parameter in power system control applications including dynamic braking, DC modulation, remedial action schemes, and system state estimation. Further research is required to determine the applications which can most effectively use real-time phase angle measurements and the best method to apply them.

Precise time dissemination and applications development on the Bonneville Power Administration system

NASA Astrophysics Data System (ADS)

Martin, Ken E.; Esztergalyos, J.

1992-07-01

The Bonneville Power Administration (BPA) uses IRIG-B transmitted over microwave as its primary system time dissemination. Problems with accuracy and reliability have led to ongoing research into better methods. BPA has also developed and deployed a unique fault locator which uses precise clocks synchronized by a pulse over microwaves. It automatically transmits the data to a central computer for analysis. A proposed system could combine fault location timing and time dissemination into a Global Position System (GPS) timing receiver and close the verification loop through a master station at the Dittmer Control Center. Such a system would have many advantages, including lower cost, higher reliability, and wider industry support. Test results indicate the GPS has sufficient accuracy and reliability for this and other current timing requirements including synchronous phase angle measurements. A phasor measurement system which provides phase angle has recently been tested with excellent results. Phase angle is a key parameter in power system control applications including dynamic braking, DC modulation, remedial action schemes, and system state estimation. Further research is required to determine the applications which can most effectively use real-time phase angle measurements and the best method to apply them.

Ergonomics, education and children: a personal view.

PubMed

Woodcock, A

2007-10-01

Educational ergonomics - the teaching of ergonomics and the design of environments where ergonomics teaching and learning might occur - has received little attention from ergonomists. This paper first describes the roots of the author's interest and research in educational ergonomics; second it provides a personal view of the opportunities and challenges posed by the two streams of educational ergonomics; and lastly it considers the implications of teaching ergonomics to children in terms of their personal development, the design of schools and the impact such initiatives might have on wider societal problems.

A generalized view of the correlation factor in solid-state diffusion

NASA Astrophysics Data System (ADS)

Akbar, Sheikh A.

1994-03-01

The correlation factor is commonly used to determine the mechanism of diffusion in solids. Although originally thought to be associated only with tracer diffusion, the concept of the correlation factor has broadened considerably over the last couple of decades. In light of these developments, it is important to generalize the concept. This article attempts to present a simple picture of an integrated view of the correlation factor in a way accessible to a wider audience. Some areas where the generalized correlation factor plays important roles are also highlighted.

Efficient fabrication method of nano-grating for 3D holographic display with full parallax views.

PubMed

Wan, Wenqiang; Qiao, Wen; Huang, Wenbin; Zhu, Ming; Fang, Zongbao; Pu, Donglin; Ye, Yan; Liu, Yanhua; Chen, Linsen

2016-03-21

Without any special glasses, multiview 3D displays based on the diffractive optics can present high resolution, full-parallax 3D images in an ultra-wide viewing angle. The enabling optical component, namely the phase plate, can produce arbitrarily distributed view zones by carefully designing the orientation and the period of each nano-grating pixel. However, such 3D display screen is restricted to a limited size due to the time-consuming fabricating process of nano-gratings on the phase plate. In this paper, we proposed and developed a lithography system that can fabricate the phase plate efficiently. Here we made two phase plates with full nano-grating pixel coverage at a speed of 20 mm²/mins, a 500 fold increment in the efficiency when compared to the method of E-beam lithography. One 2.5-inch phase plate generated 9-view 3D images with horizontal-parallax, while the other 6-inch phase plate produced 64-view 3D images with full-parallax. The angular divergence in horizontal axis and vertical axis was 1.5 degrees, and 1.25 degrees, respectively, slightly larger than the simulated value of 1.2 degrees by Finite Difference Time Domain (FDTD). The intensity variation was less than 10% for each viewpoint, in consistency with the simulation results. On top of each phase plate, a high-resolution binary masking pattern containing amplitude information of all viewing zone was well aligned. We achieved a resolution of 400 pixels/inch and a viewing angle of 40 degrees for 9-view 3D images with horizontal parallax. In another prototype, the resolution of each view was 160 pixels/inch and the view angle was 50 degrees for 64-view 3D images with full parallax. As demonstrated in the experiments, the homemade lithography system provided the key fabricating technology for multiview 3D holographic display.

[A difficult stabilisation. Chlorpromazine in the fifties in Belgium].

PubMed

Majerus, Benoît

2010-01-01

Through a Belgian case study the article tries to trace the gradual stabilisation of chlorpromazine as an antipsychotic in the 1950s. By varying ranges and angles of approach it shows the heterogeneity of actors involved and the semantic bricolage that accompany the marketing of the first antipsychotic. Far from being a revolution, the presence of Largactil in psychiatric practice is rather characterised by integration into a wider range of medicines and sinuous searching to give sense to this new drug.

SPACE FOR AUDIO-VISUAL LARGE GROUP INSTRUCTION.

ERIC Educational Resources Information Center

GAUSEWITZ, CARL H.

WITH AN INCREASING INTEREST IN AND UTILIZATION OF AUDIO-VISUAL MEDIA IN EDUCATION FACILITIES, IT IS IMPORTANT THAT STANDARDS ARE ESTABLISHED FOR ESTIMATING THE SPACE REQUIRED FOR VIEWING THESE VARIOUS MEDIA. THIS MONOGRAPH SUGGESTS SUCH STANDARDS FOR VIEWING AREAS, VIEWING ANGLES, SEATING PATTERNS, SCREEN CHARACTERISTICS AND EQUIPMENT PERFORMANCES…

Bleriot Propeller Close-up

NASA Image and Video Library

2017-05-10

This view from NASA's Cassini spacecraft shows Cassini's best image of the propeller feature known informally as Bleriot. The propeller is named after Louis Bleriot, the French engineer and aviator who in 1909 was the first person to fly across the English Channel. This is the third and final propeller to be targeted for a close flyby observation during Cassini's ring-grazing orbits (the period from Nov. 2016 to April 2017 when Cassini's orbit passed just outside the main rings). Because propellers are seen in the outermost parts of the main rings, the ring-grazing orbits provided Cassini's best opportunity to see them up close. Many small, bright specks and linear, scratch-like artifacts are visible in the image. These artifacts are due to cosmic rays and particles of radiation near the planet striking the camera detector during the exposure. Bleriot is the largest of the propellers in Saturn's rings. The wavy features embedded in the propeller structure indicate that its central moonlet is some 60 percent wider than that of Santos-Dumont, which means the Bleriot moonlet is about four times more massive. Cassini scientists have been tracking the orbit of this object for the past decade, tracing the effect that the ring has upon it. Because it is the biggest propeller, it is more easily seen in lower-resolution images than other propellers, and thus it can be spotted in the most images by far. Here, as Cassini moved in close to the rings as part of its ring-grazing orbits, it was able to obtain this extreme close-up view of the propeller, which enables researchers to examine its effects on the ring as never before. These views, and others like them, will inform models and studies in new ways going forward. This image was taken on the unilluminated side of the rings, where sunlight filters through the backlit ring. Like a frosted window, Saturn's rings look different depending on whether they are seen fully sunlit or backlit. On the lit side, the rings look darker where there is less material to reflect sunlight. On the unlit side, some regions look darker because there is less material, but other regions look dark because there is so much material that the ring becomes opaque. Most dramatically in this image, a dark band cuts deeply through the middle of Bleriot's propeller. It is much more prominent than the similar dark band in the unlit-side image of the Santos-Dumont propeller, indicating that Bleriot stirs up the ring particles to much higher densities than does Santos-Dumont. The dark bands are regions where the density is so high that the ring becomes opaque to the sunlight filtering through the rings. As in Cassini's other propeller close-up images, the central moonlet itself seems to be obscured by the stirred-up ring material around it, so that it cannot be directly seen. It would be about three pixels across, and lies at the center of the propeller structure. The image was taken using the Cassini spacecraft's narrow-angle camera on April 12. Image scale in this view is 0.3 mile (500 meters) per pixel. The sun-ring-spacecraft angle, or phase angle, is 83 degrees. https://photojournal.jpl.nasa.gov/catalog/PIA21447

The moon illusion: a different view through the legs.

PubMed

Coren, S

1992-12-01

The fact that the overestimation of the horizon moon is reduced when individuals bend over and view it through their legs has been used as support for theories of the moon illusion based upon angle of regard and vestibular inputs. Inversion of the visual scene, however, can also reduce the salience of depth cue, so illusion reduction might be consistent with size constancy explanations. A sample of 70 subjects viewed normal and inverted pictorial arrays. The moon illusion was reduced in the inverted arrays, suggesting that the "through the legs" reduction of the moon illusion may reflect the alteration in perceived depth associated with scene inversion rather than angle of regard or vestibular effects.

A Fractured Pole

NASA Image and Video Library

2015-10-15

NASA's Cassini spacecraft zoomed by Saturn's icy moon Enceladus on Oct. 14, 2015, capturing this stunning image of the moon's north pole. A companion view from the wide-angle camera (PIA20010) shows a zoomed out view of the same region for context. Scientists expected the north polar region of Enceladus to be heavily cratered, based on low-resolution images from the Voyager mission, but high-resolution Cassini images show a landscape of stark contrasts. Thin cracks cross over the pole -- the northernmost extent of a global system of such fractures. Before this Cassini flyby, scientists did not know if the fractures extended so far north on Enceladus. North on Enceladus is up. The image was taken in visible green light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 4,000 miles (6,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 9 degrees. Image scale is 115 feet (35 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA19660

Producing Science-Ready Radar Datasets for the Retrieval of Forest Structure Parameters from Backscatter: Correcting for Terrain Topography and Changes in Vegetation Reflectivity

NASA Technical Reports Server (NTRS)

Simard, M.; Riel, Bryan; Hensley, S.; Lavalle, Marco

2011-01-01

Radar backscatter data contain both geometric and radiometric distortions due to underlying topography and the radar viewing geometry. Our objective is to develop a radiometric correction algorithm specific to the UAVSAR system configuration that would improve retrieval of forest structure parameters. UAVSAR is an airborne Lband radar capable of repeat?pass interferometry producing images with a spatial resolution of 5m. It is characterized by an electronically steerable antenna to compensate for aircraft attitude. Thus, the computation of viewing angles (i.e. look, incidence and projection) must include aircraft attitude angles (i.e. yaw, pitch and roll) in addition to the antenna steering angle. In this presentation, we address two components of radiometric correction: area projection and vegetation reflectivity. The first correction is applied by normalization of the radar backscatter by the local ground area illuminated by the radar beam. The second is a correction due to changes in vegetation reflectivity with viewing geometry.

Epimetheus Above the Rings

NASA Image and Video Library

2015-11-09

Although Epimetheus appears to be lurking above the rings here, it's actually just an illusion resulting from the viewing angle. In reality, Epimetheus and the rings both orbit in Saturn's equatorial plane. Inner moons and rings orbit very near the equatorial plane of each of the four giant planets in our solar system, but more distant moons can have orbits wildly out of the equatorial plane. It has been theorized that the highly inclined orbits of the outer, distant moons are remnants of the random directions from which they approached the planets they orbit. This view looks toward the unilluminated side of the rings from about -0.3 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 26, 2015. The view was obtained at a distance of approximately 500,000 miles (800,000 kilometers) from Epimetheus and at a Sun-Epimetheus-spacecraft, or phase, angle of 62 degrees. Image scale is 3 miles (5 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18342

Emissive and reflective properties of curved displays in relation to image quality

NASA Astrophysics Data System (ADS)

Boher, Pierre; Leroux, Thierry; Bignon, Thibault; Collomb-Patton, Véronique; Blanc, Pierre; Sandré-Chardonnal, Etienne

2016-03-01

Different aspects of the characterization of curved displays are presented. The limit of validity of viewing angle measurements without angular distortion on such displays using goniometer or Fourier optics viewing angle instrument is given. If the condition cannot be fulfilled the measurement can be corrected using a general angular distortion formula as demonstrated experimentally using a Samsung Galaxy S6 edge phone display. The reflective properties of the display are characterized by measuring the spectral BRDF using a multispectral Fourier optics viewing angle system. The surface of a curved OLED TV has been measured. The BDRF patterns show a mirror like behavior with and additional strong diffraction along the pixels lines and columns that affect the quality of the display when observed with parasitic lighting. These diffraction effects are very common on OLED surfaces. We finally introduce a commercial ray tracing software that can use directly the measured emissive and reflective properties of the display to make realistic simulation under any lighting environment.

Celtic Sea

Atmospheric Science Data Center

2013-04-17

article title:  Coccoliths in the Celtic Sea     View Larger Image As ... This image is a natural-color view of the Celtic Sea and English Channel regions, and was acquired by the Multi-angle Imaging ...

Active Planning, Sensing and Recognition Using a Resource-Constrained Discriminant POMDP

DTIC Science & Technology

2014-06-28

classes of military vehicles, with sample images shown in Fig. 1. The vehicles were captured from various angles. 4785 images with depression angles 17...and 30◦ are used for training, and 4351 images with depression angles 15◦ and 45◦ are used for testing. The azimuth angles are quantized into 12...selection by collecting the engine sounds for the 8 vehicle classes from the Youtube . The sounds are attenuated differently in 6 view directions

Geometry of the Large Magellanic Cloud Using Multi- wavelength Photometry of Classical Cepheids

NASA Astrophysics Data System (ADS)

Deb, Sukanta; Ngeow, Chow-Choong; Kanbur, Shashi M.; Singh, Harinder P.; Wysocki, Daniel; Kumar, Subhash

2018-05-01

We determine the geometrical and viewing angle parameters of the Large Magellanic Cloud (LMC) using the Leavitt law based on a sample of more than 3500 common classical Cepheids (FU and FO) in optical (V, I), near-infrared (JHKs) and mid-infrared ([3.6] μm and [4.5] μm) photometric bands. Statistical reddening and distance modulus free from the effect of reddening to each of the individual Cepheids are obtained using the simultaneous multi-band fit to the apparent distance moduli from the analysis of the resulting Leavitt laws in these seven photometric bands. A reddening map of the LMC obtained from the analysis shows good agreement with the other maps available in the literature. Extinction free distance measurements along with the information of the equatorial coordinates (α, δ) for individual stars are used to obtain the corresponding Cartesian coordinates with respect to the plane of the sky. By fitting a plane solution of the form z = f(x, y) to the observed three dimensional distribution, the following viewing angle parameters of the LMC are obtained: inclination angle i = 25°.110 ± 0°.365, position angle of line of nodes θlon = 154°.702 ± 1°.378. On the other hand, modelling the observed three dimensional distribution of the Cepheids as a triaxial ellipsoid, the following values of the geometrical axes ratios of the LMC are obtained: 1.000 ± 0.003: 1.151 ± 0.003: 1.890 ± 0.014 with the viewing angle parameters: inclination angle of i = 11°.920 ± 0°.315 with respect to the longest axis from the line of sight and position angle of line of nodes θlon = 128°.871 ± 0°.569. The position angles are measured eastwards from north.

Characterization of On-Orbit U.S. Lab Condensate Vacuum Venting

NASA Astrophysics Data System (ADS)

Schmidl, W. D.; Alred, J. A.; Mikatarian, R.; Soares, C.; Miles, E.

2002-01-01

The venting of liquid streams into a vacuum has been studied extensively for many years. An experiment was performed aboard the International Space Station (ISS) to video tape the U.S. Lab's condensate venting event with cameras located on the Space Station Remote Manipulator System (SSRMS). Images of the vent plume were acquired close to both the port and starboard vent nozzles. The imaging started with a wider view and then zoomed in closer before the shutdown phase of the vent event occurred. The objective of this experiment was to extend our understanding of the properties of venting liquids into space. Data from the video images were analyzed to obtain the approximate cone angle encompassing the core of the vent plume. The condensate vent plume was characterized as having three phases, a startup phase, a nominal phase, and a shutdown phase. The startup phase consisted of the initial period when the vent first started and the liquid first entered the heated line. The nominal phase was the period when the majority of the liquid was vented. The shutdown phase occurs close to the end of the vent event. The shutdown phase was further divided into two parts, the shutdown initial phase, and a later shutdown sputtering phase. The shutdown initial phase occurs when gas becomes entrained in the condensate liquid being vented. The sputtering phase occurred after the vent valve was closed, and the liquid/ice in the line was removed by continuing to heat the line to bake it out. It was determined that the ice particles were ejected at higher angles, but lower velocities, during the startup and shutdown phases. The number and velocities of ice particles ejected outside of the core region, during the startup, initial shutdown and shutdown sputtering phases were determined. The core of liquid ejected during the startup and shutdown phases was contained within a half cone angle of less than 60 degrees. The startup phase took approximately 36 seconds, the shutdown initial phase took approximately 22 seconds, and the shutdown sputtering phase took approximately 32 seconds. Results from the experiment were correlated with the Boeing ISS vent plume model.

Reflection color filters of the three primary colors with wide viewing angles using common-thickness silicon subwavelength gratings.

PubMed

Kanamori, Yoshiaki; Ozaki, Toshikazu; Hane, Kazuhiro

2014-10-20

We fabricated reflection color filters of the three primary colors with wide viewing angles using silicon two-dimensional subwavelength gratings on the same quartz substrate. The grating periods were 400, 340, and 300 nm for red, green, and blue filters, respectively. All of the color filters had the same grating thickness of 100 nm, which enabled simple fabrication of a color filter array. Reflected colors from the red, green, and blue filters under s-polarized white-light irradiation appeared in the respective colors at incident angles from 0 to 50°. By rigorous coupled-wave analysis, the dimensions of each color filter were designed, and the calculated reflectivity was compared with the measured reflectivity.

Earth Observations taken by the STS-112 crew

NASA Image and Video Library

2002-10-13

STS112-707-035 (7-18 October 2002) --- The Colorado River snakes across this view, photographed from the Space Shuttle Atlantis, from top left (near the vehicle’s vertical stabilizer), to the lower right, where the Grand Canyon gorge can be detected. The wider blue parts of the Colorado in the center of the view are Lake Powell, an artificial lake more than 120 miles long. The dark green areas are wooded slopes generally above 6000 feet. The Kaibab Plateau (lower left) and the range with Abajo Peak (11,360 feet, Utah-Colorado border region) cross the top of the view. The red areas are lower and semiarid, dominated by desert scrub vegetation.

The influence of radiographic viewing perspective and demographics on the Critical Shoulder Angle

PubMed Central

Suter, Thomas; Popp, Ariane Gerber; Zhang, Yue; Zhang, Chong; Tashjian, Robert Z.; Henninger, Heath B.

2014-01-01

Background Accurate assessment of the critical shoulder angle (CSA) is important in clinical evaluation of degenerative rotator cuff tears. This study analyzed the influence of radiographic viewing perspective on the CSA, developed a classification system to identify malpositioned radiographs, and assessed the relationship between the CSA and demographic factors. Methods Glenoid height, width and retroversion were measured on 3D CT reconstructions of 68 cadaver scapulae. A digitally reconstructed radiograph was aligned perpendicular to the scapular plane, and retroversion was corrected to obtain a true antero-posterior (AP) view. In 10 scapulae, incremental anteversion/retroversion and flexion/extension views were generated. The CSA was measured and a clinically applicable classification system was developed to detect views with >2° change in CSA versus true AP. Results The average CSA was 33±4°. Intra- and inter-observer reliability was high (ICC≥0.81) but decreased with increasing viewing angle. Views beyond 5° anteversion, 8° retroversion, 15° flexion and 26° extension resulted in >2° deviation of the CSA compared to true AP. The classification system was capable of detecting aberrant viewing perspectives with sensitivity of 95% and specificity of 53%. Correlations between glenoid size and CSA were small (R≤0.3), and CSA did not vary by gender (p=0.426) or side (p=0.821). Conclusions The CSA was most susceptible to malposition in ante/retroversion. Deviations as little as 5° in anteversion resulted in a CSA >2° from true AP. A new classification system refines the ability to collect true AP radiographs of the scapula. The CSA was unaffected by demographic factors. PMID:25591458

Microwave Brightness Temperatures of Tilted Convective Systems

NASA Technical Reports Server (NTRS)

Hong, Ye; Haferman, Jeffrey L.; Olson, William S.; Kummerow, Christian D.

1998-01-01

Aircraft and ground-based radar data from the Tropical Ocean and Global Atmosphere Coupled-Ocean Atmosphere Response Experiment (TOGA COARE) show that convective systems are not always vertical. Instead, many are tilted from vertical. Satellite passive microwave radiometers observe the atmosphere at a viewing angle. For example, the Special Sensor Microwave/Imager (SSM/I) on Defense Meteorological Satellite Program (DMSP) satellites and the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) on the TRMM satellite have an incident angle of about 50deg. Thus, the brightness temperature measured from one direction of tilt may be different than that viewed from the opposite direction due to the different optical depth. This paper presents the investigation of passive microwave brightness temperatures of tilted convective systems. To account for the effect of tilt, a 3-D backward Monte Carlo radiative transfer model has been applied to a simple tilted cloud model and a dynamically evolving cloud model to derive the brightness temperature. The radiative transfer results indicate that brightness temperature varies when the viewing angle changes because of the different optical depth. The tilt increases the displacements between high 19 GHz brightness temperature (Tb(sub 19)) due to liquid emission from lower level of cloud and the low 85 GHz brightness temperature (Tb(sub 85)) due to ice scattering from upper level of cloud. As the resolution degrades, the difference of brightness temperature due to the change of viewing angle decreases dramatically. The dislocation between Tb(sub 19) and Tb(sub 85), however, remains prominent.

Are two different projections of the inlet view necessary for the percutaneous placement of iliosacral screws?

PubMed

Ozmeric, A; Yucens, M; Gultaç, E; Açar, H I; Aydogan, N H; Gül, D; Alemdaroglu, K B

2015-05-01

We hypothesised that the anterior and posterior walls of the body of the first sacral vertebra could be visualised with two different angles of inlet view, owing to the conical shape of the sacrum. Six dry male cadavers with complete pelvic rings and eight dry sacrums with K-wires were used to study the effect of canting (angling the C-arm) the fluoroscope towards the head in 5° increments from 10° to 55°. Fluoroscopic images were taken in each position. Anterior and posterior angles of inclination were measured between the upper sacrum and the vertical line on the lateral view. Three authors separately selected the clearest image for overlapping anterior cortices and the upper sacral canal in the cadaveric models. The dry bone and K-wire models were scored by the authors, being sure to check whether the K-wire was in or out. In the dry bone models the mean score of the relevant inlet position of the anterior or posterior inclination was 8.875 (standard deviation (sd) 0.35), compared with the inlet position of the opposite inclination of -5.75 (sd 4.59). We found that two different inlet views should be used separately to evaluate the borders of the body of the sacrum using anterior and posterior inclination angles of the sacrum, during placement of iliosacral screws. ©2015 The British Editorial Society of Bone & Joint Surgery.

Rings Through Atmosphere

NASA Image and Video Library

2010-05-26

NASA Cassini spacecraft looks toward the limb of Saturn and, on the right of this image, views part of the rings through the planet atmosphere. Saturn atmosphere can distort the view of the rings from some angles.

New Mexico: Los Alamos

Atmospheric Science Data Center

2014-05-15

article title:  Los Alamos, New Mexico     View Larger JPEG image ... kb) Multi-angle views of the Fire in Los Alamos, New Mexico, May 9, 2000. These true-color images covering north-central New Mexico ...

A Low-Cost PC-Based Image Workstation for Dynamic Interactive Display of Three-Dimensional Anatomy

NASA Astrophysics Data System (ADS)

Barrett, William A.; Raya, Sai P.; Udupa, Jayaram K.

1989-05-01

A system for interactive definition, automated extraction, and dynamic interactive display of three-dimensional anatomy has been developed and implemented on a low-cost PC-based image workstation. An iconic display is used for staging predefined image sequences through specified increments of tilt and rotation over a solid viewing angle. Use of a fast processor facilitates rapid extraction and rendering of the anatomy into predefined image views. These views are formatted into a display matrix in a large image memory for rapid interactive selection and display of arbitrary spatially adjacent images within the viewing angle, thereby providing motion parallax depth cueing for efficient and accurate perception of true three-dimensional shape, size, structure, and spatial interrelationships of the imaged anatomy. The visual effect is that of holding and rotating the anatomy in the hand.

Challenging Popular Media's Control by Teaching Critical Viewing.

ERIC Educational Resources Information Center

Couch, Richard A.

The purpose of this paper is to express the importance of visual/media literacy and the teaching of critical television viewing. An awareness of the properties and characteristics of television--including camera angles and placement, editing, and emotionally involving subject matter--aids viewers in the critical viewing process. The knowledge of…

Development of Human Posture Simulation Method for Assessing Posture Angles and Spinal Loads

PubMed Central

Lu, Ming-Lun; Waters, Thomas; Werren, Dwight

2015-01-01

Video-based posture analysis employing a biomechanical model is gaining a growing popularity for ergonomic assessments. A human posture simulation method of estimating multiple body postural angles and spinal loads from a video record was developed to expedite ergonomic assessments. The method was evaluated by a repeated measures study design with three trunk flexion levels, two lift asymmetry levels, three viewing angles and three trial repetitions as experimental factors. The study comprised two phases evaluating the accuracy of simulating self and other people’s lifting posture via a proxy of a computer-generated humanoid. The mean values of the accuracy of simulating self and humanoid postures were 12° and 15°, respectively. The repeatability of the method for the same lifting condition was excellent (~2°). The least simulation error was associated with side viewing angle. The estimated back compressive force and moment, calculated by a three dimensional biomechanical model, exhibited a range of 5% underestimation. The posture simulation method enables researchers to simultaneously quantify body posture angles and spinal loading variables with accuracy and precision comparable to on-screen posture matching methods. PMID:26361435

High-efficiency directional backlight design for an automotive display.

PubMed

Chen, Bo-Tsuen; Pan, Jui-Wen

2018-06-01

We propose a high-efficiency directional backlight module (DBM) for automotive display applications. The DBM is composed of light sources, a light guide plate (LGP), and an optically patterned plate (OPP). The LGP has a collimator on the input surface that serves to control the angle of the light emitted to be in the horizontal direction. The OPP has an inverse prism to adjust the light emission angle in the vertical direction. The DBM has a simple structure and high optical efficiency. Compared with conventional backlight systems, the DBM has higher optical efficiency and a suitable viewing angle. This is an improvement in normalized on-axis luminous intensity of 2.6 times and a twofold improvement in optical efficiency. The viewing angles are 100° in the horizontal direction and 35° in the vertical direction. The angle of the half-luminous intensity is 72° in the horizontal direction and 20° in the vertical direction. The uniformity of the illuminance reaches 82%. The DBM is suitable for use in the center information displays of automobiles.

Structurally colored films with superhydrophobicity and wide viewing angles based on bumpy melanin-like particles

NASA Astrophysics Data System (ADS)

Yi, Bo; Shen, Huifang

2018-01-01

Non-iridescent structural colors and lotus effect universally existing in the nature provide a great inspiration for artificially developing angle-independent and high hydrophobic structurally colored films. To this end, a facile strategy is put forward for achieving superhydrophobic structurally colored films with wide viewing angles and high visibility based on bumpy melanin-like polydopamine-coated polystyrene particles. Here, hierarchical and amorphous structures are assembled in a self-driven manner due to particles' protrusive surfaces. The superhydrophobicity of the structurally colored films, with water contact angle up to 151°, is realized by combining the hierarchical surface roughness with a dip-coating process of polydimethylsiloxane-hexane solution, while angle-independence revealed in the films is ascribed to amorphous arrays. In addition, benefited from an essential light-absorbing property and high refractive index of polydopamine, the visibility of as-prepared colored films is fundamentally enhanced. Moreover, the mechanical robustness of the films is considerably boosted by inletting 3-aminopropyltriethoxysilane. This fabrication strategy might provide an opportunity for promoting the open-air application of structurally colored coatings.

Impact of basic angle variations on the parallax zero point for a scanning astrometric satellite

NASA Astrophysics Data System (ADS)

Butkevich, Alexey G.; Klioner, Sergei A.; Lindegren, Lennart; Hobbs, David; van Leeuwen, Floor

2017-07-01

Context. Determination of absolute parallaxes by means of a scanning astrometric satellite such as Hipparcos or Gaia relies on the short-term stability of the so-called basic angle between the two viewing directions. Uncalibrated variations of the basic angle may produce systematic errors in the computed parallaxes. Aims: We examine the coupling between a global parallax shift and specific variations of the basic angle, namely those related to the satellite attitude with respect to the Sun. Methods: The changes in observables produced by small perturbations of the basic angle, attitude, and parallaxes were calculated analytically. We then looked for a combination of perturbations that had no net effect on the observables. Results: In the approximation of infinitely small fields of view, it is shown that certain perturbations of the basic angle are observationally indistinguishable from a global shift of the parallaxes. If these kinds of perturbations exist, they cannot be calibrated from the astrometric observations but will produce a global parallax bias. Numerical simulations of the astrometric solution, using both direct and iterative methods, confirm this theoretical result. For a given amplitude of the basic angle perturbation, the parallax bias is smaller for a larger basic angle and a larger solar aspect angle. In both these respects Gaia has a more favourable geometry than Hipparcos. In the case of Gaia, internal metrology is used to monitor basic angle variations. Additionally, Gaia has the advantage of detecting numerous quasars, which can be used to verify the parallax zero point.

Complete 360° circumferential gonioscopic optical coherence tomography imaging of the iridocorneal angle

PubMed Central

McNabb, Ryan P.; Challa, Pratap; Kuo, Anthony N.; Izatt, Joseph A.

2015-01-01

Clinically, gonioscopy is used to provide en face views of the ocular angle. The angle has been imaged with optical coherence tomography (OCT) through the corneoscleral limbus but is currently unable to image the angle from within the ocular anterior chamber. We developed a novel gonioscopic OCT system that images the angle circumferentially from inside the eye through a custom, radially symmetric, gonioscopic contact lens. We present, to our knowledge, the first 360° circumferential volumes (two normal subjects, two subjects with pathology) of peripheral iris and iridocorneal angle structures obtained via an internal approach not typically available in the clinic. PMID:25909021

Is "end of life" a special case? Connecting Q with survey methods to measure societal support for views on the value of life-extending treatments.

PubMed

Mason, Helen; Collins, Marissa; McHugh, Neil; Godwin, Jon; Van Exel, Job; Donaldson, Cam; Baker, Rachel

2018-05-01

Preference elicitation studies reporting societal views on the relative value of end-of-life treatments have produced equivocal results. This paper presents an alternative method, combining Q methodology and survey techniques (Q2S) to determine the distribution of 3 viewpoints on the relative value of end-of-life treatments identified in a previous, published, phase of this work. These were Viewpoint 1, "A population perspective: value for money, no special cases"; Viewpoint 2, "Life is precious: valuing life-extension and patient choice"; and Viewpoint 3, "Valuing wider benefits and opportunity cost: the quality of life and death." A Q2S survey of 4,902 respondents across the United Kingdom measured agreement with these viewpoints; 37% most agreed with Viewpoint 1, 49% with Viewpoint 2, and 9% with Viewpoint 3. Regression analysis showed associations of viewpoints with gender, level of education, religion, voting preferences, and satisfaction with the NHS. The Q2S approach provides a promising means to investigate how in-depth views and opinions are represented in the wider population. As demonstrated in this study, there is often more than 1 viewpoint on a topic and methods that seek to estimate that averages may not provide the best guidance for societal decision-making. © 2018 The Authors. Health Economics Published by John Wiley & Sons Ltd.

Framing the relationship between people and nature in the context of European conservation.

PubMed

Linnell, John D C; Kaczensky, Petra; Wotschikowsky, Ulrich; Lescureux, Nicolas; Boitani, Luigi

2015-08-01

A key controversy in conservation is the framing of the relationship between people and nature. The extent to which the realms of nature and human culture are viewed as separate (dualistic view) or integrated is often discussed in the social sciences. To explore how this relationship is represented in the practice of conservation in Europe, we considered examples of cultural landscapes, wildlife (red deer, reindeer, horses), and protected area management. We found little support, for a dualistic worldview, where people and nature are regarded as separate in the traditional practice of conservation in Europe. The borders between nature and culture, wild and domestic, public land and private land, and between protected areas and the wider landscape were blurred and dynamic. The institutionalized (in practice and legislation) view is of an interactive mutualistic system in which humans and nature share the whole landscape. However, more dualistic ideals, such as wilderness and rewilding that are challenging established practices are expanding. In the context of modern day Europe, wilderness conservation and rewilding are not valid for the whole landscape, although it is possible to integrate some areas of low-intervention management into a wider matrix. A precondition for success is to recognize and plan for a plurality of values concerning the most valid approaches to conservation and to plan for this plurality at the landscape scale. © 2015 Society for Conservation Biology.

Separating Judicial from Legislative Reasoning in Moral Dilemma Interviews.

PubMed

Langford, Peter E

1997-12-01

Unlike previous studies of the development of reasoning about moral dilemmas, the 2 studies reported separated judicial reasoning (the application of rules) from legislative reasoning (the justification of rules), as well as attending to other aspects of context, using a modification of the weakly interpretive scoring method of Langford and D'Cruz. This assigns justifications to relatively simple conceptually defined categories. Findings were in accord with substantially modified versions of the views of Piaget and Kohlberg, according to which legislative reasoning can be divided into 3 main types of stages in the period 7-21 years: heteronomy (Piaget) or egocentrism (Kohlberg); local groups (attention to group interests, harmony, and reciprocity in local groups), wider groups (attention to these thing in wider groups). Findings contradicted Gibbs's theory.

7. VAL CAMERA STATION, INTERIOR VIEW OF CAMERA MOUNT, COMMUNICATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VAL CAMERA STATION, INTERIOR VIEW OF CAMERA MOUNT, COMMUNICATION EQUIPMENT AND STORAGE CABINET. - Variable Angle Launcher Complex, Camera Stations, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

3. VAL CONTROL STATION, VIEW OF CONTROL PANELS SHOWING MAIN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VAL CONTROL STATION, VIEW OF CONTROL PANELS SHOWING MAIN PRESSURE GAUGES, LOOKING NORTH. - Variable Angle Launcher Complex, Control Station, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Monte Carlo-based assessment of the trade-off between spatial resolution, field-of-view and scattered radiation in the variable resolution X-ray CT scanner.

PubMed

Arabi, Hossein; Kamali Asl, Ali Reza; Ay, Mohammad Reza; Zaidi, Habib

2015-07-01

The purpose of this work is to evaluate the impact of optimization of magnification on performance parameters of the variable resolution X-ray (VRX) CT scanner. A realistic model based on an actual VRX CT scanner was implemented in the GATE Monte Carlo simulation platform. To evaluate the influence of system magnification, spatial resolution, field-of-view (FOV) and scatter-to-primary ratio of the scanner were estimated for both fixed and optimum object magnification at each detector rotation angle. Comparison and inference between these performance parameters were performed angle by angle to determine appropriate object position at each opening half angle. Optimization of magnification resulted in a trade-off between spatial resolution and FOV of the scanner at opening half angles of 90°-12°, where the spatial resolution increased up to 50% and the scatter-to-primary ratio decreased from 4.8% to 3.8% at a detector angle of about 90° for the same FOV and X-ray energy spectrum. The disadvantage of magnification optimization at these angles is the significant reduction of the FOV (up to 50%). Moreover, magnification optimization was definitely beneficial for opening half angles below 12° improving the spatial resolution from 7.5 cy/mm to 20 cy/mm. Meanwhile, the FOV increased by more than 50% at these angles. It can be concluded that optimization of magnification is essential for opening half angles below 12°. For opening half angles between 90° and 12°, the VRX CT scanner magnification should be set according to the desired spatial resolution and FOV. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Measuring the Radius of the Earth from a Mountain Top Overlooking the Ocean

ERIC Educational Resources Information Center

Gangadharan, Dhevan

2009-01-01

A clear view of the ocean may be used to measure the radius of the Earth. To an observer looking out at the ocean, the horizon will always form some angle [theta] with the local horizontal plane. As the observer's elevation "h" increases, so does the angle [theta]. From measurements of the elevation "h" and the angle [theta],…

Seawifs Technical Report Series. Volume 2: Analysis of Orbit Selection for Seawifs: Ascending Versus Descending Node

NASA Technical Reports Server (NTRS)

Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Gregg, Watson W.

1992-01-01

Due to range safety considerations, the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) ocean color instrument may be required to be launched into a near-noon descending node, as opposed to the ascending node used by the predecessor sensor, the Coastal Zone Color Scanner (CZCS). The relative importance of ascending versus descending near-noon orbits was assessed here to determine if descending node will meet the scientific requirements of SeaWiFS. Analyses focused on ground coverage, local times of coverage, solar and viewing geometries (zenith and azimuth angles), and sun glint. Differences were found in the areas covered by individual orbits, but were not important when taken over a 16 day repeat time. Local time of coverage was also different: for ascending node orbits the Northern Hemisphere was observed in the morning and the Southern Hemisphere in the afternoon, while for descending node orbits the Northern Hemisphere was observed in the afternoon and the Southern in the morning. There were substantial differences in solar azimuth and spacecraft azimuth angles both at equinox and at the Northern Hemisphere summer solstice. Negligible differences in solar and spacecraft zenith angles, relative azimuth angles, and sun glint were obtained at the equinox. However, large differences were found in solar zenith angles, relative azimuths, and sun glint for the solstice. These differences appeared to compensate across the scan, however, an increase in sun glint in descending node over that in ascending node on the western part of the scan was compensated by a decrease on the eastern part of the scan. Thus, no advantage or disadvantage could be conferred upon either ascending node or descending node for noon orbits. Analyses were also performed for ascending and descending node orbits that deviated from a noon equator crossing time. For ascending node, afternoon orbits produced the lowest mean solar zenith angles in the Northern Hemisphere, and morning orbits produced the lowest angles for the Southern Hemisphere. For descending node, morning orbits produced the lowest mean solar zenith angles for the Northern Hemisphere; afternoon orbits produced the lowest angles for the Southern Hemisphere.

Angle-domain inverse scattering migration/inversion in isotropic media

NASA Astrophysics Data System (ADS)

Li, Wuqun; Mao, Weijian; Li, Xuelei; Ouyang, Wei; Liang, Quan

2018-07-01

The classical seismic asymptotic inversion can be transformed into a problem of inversion of generalized Radon transform (GRT). In such methods, the combined parameters are linearly attached to the scattered wave-field by Born approximation and recovered by applying an inverse GRT operator to the scattered wave-field data. Typical GRT-style true-amplitude inversion procedure contains an amplitude compensation process after the weighted migration via dividing an illumination associated matrix whose elements are integrals of scattering angles. It is intuitional to some extent that performs the generalized linear inversion and the inversion of GRT together by this process for direct inversion. However, it is imprecise to carry out such operation when the illumination at the image point is limited, which easily leads to the inaccuracy and instability of the matrix. This paper formulates the GRT true-amplitude inversion framework in an angle-domain version, which naturally degrades the external integral term related to the illumination in the conventional case. We solve the linearized integral equation for combined parameters of different fixed scattering angle values. With this step, we obtain high-quality angle-domain common-image gathers (CIGs) in the migration loop which provide correct amplitude-versus-angle (AVA) behavior and reasonable illumination range for subsurface image points. Then we deal with the over-determined problem to solve each parameter in the combination by a standard optimization operation. The angle-domain GRT inversion method keeps away from calculating the inaccurate and unstable illumination matrix. Compared with the conventional method, the angle-domain method can obtain more accurate amplitude information and wider amplitude-preserved range. Several model tests demonstrate the effectiveness and practicability.

High angle view of Apollo 14 space vehicle on way to Pad A

NASA Image and Video Library

1970-11-09

S70-54127 (9 Nov. 1970) --- A high-angle view at Launch Complex 39, Kennedy Space Center (KSC), showing the Apollo 14 (Spacecraft 110/Lunar Module 8/Saturn 509) space vehicle on the way from the Vehicle Assembly Building (VAB) to Pad A. The Saturn V stack and its mobile launch tower sit atop a huge crawler-transporter. The Apollo 14 crewmen will be astronauts Alan B. Shepard Jr., commander; Stuart A. Roosa, command module pilot; and Edgar D. Mitchell, lunar module pilot.

High angle view of Apollo 14 space vehicle on way to Pad A

NASA Image and Video Library

1970-11-09

S70-54119 (9 Nov. 1970) --- A high-angle view at Launch Complex 39, Kennedy Space Center (KSC), showing the Apollo 14 (Spacecraft 110/Lunar Module 8/Saturn 509) space vehicle on the way from the Vehicle Assembly Building (VAB) to Pad A. The Saturn V stack and its mobile launch tower sit atop a huge crawler-transporter. The Apollo 14 crewmen will be astronauts Alan B. Shepard Jr., commander; Stuart A. Roosa, command module pilot; and Edgar D. Mitchell, lunar module pilot.

Inventory and monitoring of natural vegetation and related resources in an arid environment

NASA Technical Reports Server (NTRS)

Schrumpf, B. J. (Principal Investigator); Johnson, J. R.; Mouat, D. A.

1973-01-01

The author has identified the following significant results. A vegetation classification has been established for the test site (approx. 8300 sq km); 31 types are recognized. Some relationships existing among vegetation types and associated terrain features have been characterized. Terrain features can be used to discriminate vegetation types. Macrorelief interpretations on ERTS-1 imagery can be performed with greater accuracy when using high sun angle stereoscopic viewing rather than low sun angle monoscopic viewing. Some plant phenological changes are being recorded by the MSS system.

Scheduling Randomly-Deployed Heterogeneous Video Sensor Nodes for Reduced Intrusion Detection Time

NASA Astrophysics Data System (ADS)

Pham, Congduc

This paper proposes to use video sensor nodes to provide an efficient intrusion detection system. We use a scheduling mechanism that takes into account the criticality of the surveillance application and present a performance study of various cover set construction strategies that take into account cameras with heterogeneous angle of view and those with very small angle of view. We show by simulation how a dynamic criticality management scheme can provide fast event detection for mission-critical surveillance applications by increasing the network lifetime and providing low stealth time of intrusions.

Leaf bidirectional reflectance and transmittance in corn and soybean

NASA Technical Reports Server (NTRS)

Walter-Shea, E. A.; Norman, J. M.; Blad, B. L.

1989-01-01

Bidirectional optical properties of leaves must be adequately characterized to develop comprehensive and reliably predictive canopy radiative-transfer models. Directional reflectance and transmittance factors of individual corn and soybean leaves were measured at source incidence angles (SIAs) 20, 45, and 70 deg and numerous view angles in the visible and NIR. Bidirectional reflectance distributions changed with increasing SIA, with forward scattering most pronounced at 70 deg. Directional-hemispherical reflectance generally increased and transmittance decreased with increased SIA. Directional-hemispherical reflectance factors were higher and transmittances were lower than the nadir-viewed reflectance component.

Temps in Teaching: The Role of Private Employment Agencies in a Changing Labour Market for Teachers.

ERIC Educational Resources Information Center

Morrison, Marlene

1999-01-01

Explores the emergence of (British) teacher employment agencies and the increased volume of employment agency business in teaching, drawing on interviews with agency representatives. Views agencies as part of a wider agenda that includes marketization and privatization trends mirrored in further education. Part-time teaching is on the rise.…

Young People and Healthy Eating: A Systematic Review of Research on Barriers and Facilitators

ERIC Educational Resources Information Center

Shepherd, J.; Harden, A.; Rees, R.; Brunton, G.; Garcia, J.; Oliver, S.; Oakley, A.

2006-01-01

A systematic review was conducted to examine the barriers to, and facilitators of, healthy eating among young people (11-16 years). The review focused on the wider determinants of health, examining community- and society-level interventions. Seven outcome evaluations and eight studies of young people's views were included. The effectiveness of the…

An Evaluation of Web Based Instruction in View of the Tutors' and Students' Perspectives

ERIC Educational Resources Information Center

Erdogan, Yavuz

2008-01-01

In today's world, it is acknowledged by almost all folks of life that the traditional educational institutions are inadequate in educating the growing population. This situation has triggered research into finding ways to provide economical and of high quality education to wider masses of people. Currently, web based instruction seems to be the…

Perceptions Audit for the General Teaching Council for England. Technical Report

ERIC Educational Resources Information Center

Levitt, Ruth; Rabinovich, Lila; van Dijk, Lidia Villalba

2009-01-01

The General Teaching Council for England (GTC) commissioned RAND Europe in 2008 to undertake a perceptions audit, to take the temperature on its current status and to inform its future work with teachers, organisational partners and the wider public. A perceptions audit is a method for gathering opinions and views of selected informants about how…

Chronotopoi of the Good Life and Utopia: Bakhtin on Goethe's "Bildungsroman Wilhelm Meister" and the Carnivalesque

ERIC Educational Resources Information Center

Franke, Norman

2017-01-01

This paper explores Bakhtin's reception of Goethe's "Wilhelm Meisters Lehrjahre" with a view to assess how Bakhtin's interest in this early chronotopical masterpiece can be understood in the wider context of his utopian thinking and his political eschatologies. Bakhtin reads Goethe's novel as a critique of totalitarian forms of Socialist…

Structural Changes in the Polish Higher Education System (1990-2010): A Synthetic View

ERIC Educational Resources Information Center

Kwiek, Marek

2014-01-01

The paper locates the past two decades of changes in Polish universities in a comparative European context. It shows a wider transition: from an expanding, privatized and disciplinarily divided university of the 1990s to a publicly funded, increasingly contracting and stratified university of the 2000s (and beyond). The gradual political and…

What Does Your ASE Membership Say about You?

ERIC Educational Resources Information Center

Lawrence, Liz

2009-01-01

In this article, the author shares her view about her ASE membership and what it says about her. What she hopes her ASE membership says about her is that she is committed to her own professional development and the professional development of others; she values the opportunity to engage with the wider perspective, to take on responsibilities or…

Gutter to Garden: Historical Discourses of Risk in Interventions in Working Class Children's Street Play

ERIC Educational Resources Information Center

Read, Jane

2011-01-01

This article investigates interventions in the gutter play of British working class children in the first decade of the 20th century through their re-location within Free Kindergartens. In contemporary literature, the street child was viewed through a binary lens, as both "at risk" and "as risk", reflecting wider societal…

What PISA Tells Us about the Quality and Inequality of Japanese Education in Mathematics and Science

ERIC Educational Resources Information Center

Knipprath, Heidi

2010-01-01

Researchers, policy officials, and the wider public in Japan and abroad often hold different views about the quality of Japanese education. Whereas Western researchers are attracted by the academic performance of Japanese students in international assessment studies, Japanese university professors launched a public debate in 1999 about declining…

Whatever Happens to Him Happens to Us: Reading Coyote Reading the World.

ERIC Educational Resources Information Center

Clifford, Patricia; Friesen, Sharon; Jardine, David W.

2001-01-01

Denounces the mechanical application of "diagnosis and treatment" of educational ills to children and proposes to seek wider contexts in which to view the life of the child and of the teacher. Uses a case study employing a Native American archetypal character to explore ways of reading differently the difficult, abnormal, troubled children in the…

Can orbital angle morphology distinguish dogs from wolves?

PubMed

Janssens, Luc; Spanoghe, Inge; Miller, Rebecca; Van Dongen, Stefan

For more than a century, the orbital angle has been studied by many authors to distinguish dog skulls from their progenitor, the wolf. In early studies, the angle was reported to be different between dogs (49°-55°) and wolves (39°-46°). This clear difference was, however, questioned in a more recent Scandinavian study that shows some overlap. It is clear that in all studies several methodological issues were unexplored or unclear and that group sizes and the variety of breeds and wolf subspecies were small. Archaeological dog skulls had also not been studied. Our goal was to test larger and more varied groups and add archaeological samples as they are an evolutionary stage between wolves and modern dogs. We also tested the influence of measuring methods, intra- and inter-reliability, angle symmetry, the influence of variations in skull position and the possibility of measuring and comparing this angle on 3D CT scan images. Our results indicate that there is about 50 % overlap between the angle range in wolves and modern dogs. However, skulls with a very narrow orbital angle were only found in wolves and those with a very wide angle only in dogs. Archaeological dogs have a mean angle very close to the one of the wolves. Symmetry is highest in wolves and lowest in archaeological dogs. The measuring method is very reliable, for both inter- and intra-reliability (0.99-0.97), and most skull position changes have no statistical influence on the angle measured. Three-dimensional CT scan images can be used to measure OA, but the angles differ from direct measuring and cannot be used for comparison. Evolutionary changes in dog skulls responsible for the wider OA compared to wolf skulls are mainly the lateralisation of the zygomatic process of the frontal bone. Our conclusion is that the orbital angle can be used as an additional morphological measuring method to discern wolves from recent and archaeological dogs. Angles above 60° are certainly from recent dogs. Angles under 35° are certainly of wolves.

2. OBLIQUE VIEW OF WEST FRONT. The frames on an ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. OBLIQUE VIEW OF WEST FRONT. The frames on an angle originally held mirrors for viewing the tests from inside the building. Vertical frame originally held bullet glass. - Edwards Air Force Base, South Base Sled Track, Firing Control Blockhouse, South of Sled Track at east end, Lancaster, Los Angeles County, CA

Reflection and emission models for deserts derived from Nimbus-7 ERB scanner measurements

NASA Technical Reports Server (NTRS)

Staylor, W. F.; Suttles, J. T.

1986-01-01

Broadband shortwave and longwave radiance measurements obtained from the Nimbus-7 Earth Radiation Budget scanner were used to develop reflectance and emittance models for the Sahara-Arabian, Gibson, and Saudi Deserts. The models were established by fitting the satellite measurements to analytic functions. For the shortwave, the model function is based on an approximate solution to the radiative transfer equation. The bidirectional-reflectance function was obtained from a single-scattering approximation with a Rayleigh-like phase function. The directional-reflectance model followed from integration of the bidirectional model and is a function of the sum and product of cosine solar and viewing zenith angles, thus satisfying reciprocity between these angles. The emittance model was based on a simple power-law of cosine viewing zenith angle.

Color image generation for screen-scanning holographic display.

PubMed

Takaki, Yasuhiro; Matsumoto, Yuji; Nakajima, Tatsumi

2015-10-19

Horizontally scanning holography using a microelectromechanical system spatial light modulator (MEMS-SLM) can provide reconstructed images with an enlarged screen size and an increased viewing zone angle. Herein, we propose techniques to enable color image generation for a screen-scanning display system employing a single MEMS-SLM. Higher-order diffraction components generated by the MEMS-SLM for R, G, and B laser lights were coupled by providing proper illumination angles on the MEMS-SLM for each color. An error diffusion technique to binarize the hologram patterns was developed, in which the error diffusion directions were determined for each color. Color reconstructed images with a screen size of 6.2 in. and a viewing zone angle of 10.2° were generated at a frame rate of 30 Hz.

8. VAL CAMERA CAR, CLOSEUP VIEW OF 'FLARE' OR TRAJECTORY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VAL CAMERA CAR, CLOSE-UP VIEW OF 'FLARE' OR TRAJECTORY CAMERA ON SLIDING MOUNT. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

18. DETAIL VIEW OF DEVICE ON OUTSIDE OF COFFEE HUSKER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. DETAIL VIEW OF DEVICE ON OUTSIDE OF COFFEE HUSKER THAT ADJUSTED ANGLE OF HUSKER VAT WALLS - Hacienda Cafetalera Santa Clara, Coffee Mill, KM 19, PR Route 372, Hacienda La Juanita, Yauco Municipio, PR

2. VAL CONTROL STATION, VIEW OF INTERIOR SHOWING EXTERIOR DOOR, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VAL CONTROL STATION, VIEW OF INTERIOR SHOWING EXTERIOR DOOR, WINDOWS AND CONTROL PANELS, LOOKING SOUTHEAST. - Variable Angle Launcher Complex, Control Station, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Ground-based full-sky imaging polarimeter based on liquid crystal variable retarders.

PubMed

Zhang, Ying; Zhao, Huijie; Song, Ping; Shi, Shaoguang; Xu, Wujian; Liang, Xiao

2014-04-07

A ground-based full-sky imaging polarimeter based on liquid crystal variable retarders (LCVRs) is proposed in this paper. Our proposed method can be used to realize the rapid detection of the skylight polarization information with hemisphere field-of-view for the visual band. The characteristics of the incidence angle of light on the LCVR are investigated, based on the electrically controlled birefringence. Then, the imaging polarimeter with hemisphere field-of-view is designed. Furthermore, the polarization calibration method with the field-of-view multiplexing and piecewise linear fitting is proposed, based on the rotation symmetry of the polarimeter. The polarization calibration of the polarimeter is implemented with the hemisphere field-of-view. This imaging polarimeter is investigated by the experiment of detecting the skylight image. The consistency between the obtained experimental distribution of polarization angle with that due to Rayleigh scattering model is 90%, which confirms the effectivity of our proposed imaging polarimeter.

Flow visualization and characterization of evaporating liquid drops

NASA Technical Reports Server (NTRS)

Chao, David F. (Inventor); Zhang, Nengli (Inventor)

2004-01-01

An optical system, consisting of drop-reflection image, reflection-refracted shadowgraphy and top-view photography, is used to measure the spreading and instant dynamic contact angle of a volatile-liquid drop on a non-transparent substrate. The drop-reflection image and the shadowgraphy is shown by projecting the images of a collimated laser beam partially reflected by the drop and partially passing through the drop onto a screen while the top view photograph is separately viewed by use of a camera video recorder and monitor. For a transparent liquid on a reflective solid surface, thermocapillary convection in the drop, induced by evaporation, can be viewed nonintrusively, and the drop real-time profile data are synchronously recorded by video recording systems. Experimental results obtained from this technique clearly reveal that evaporation and thermocapillary convection greatly affect the spreading process and the characteristics of dynamic contact angle of the drop.

Exploitation of the UV Aerosol Index scattering angle dependence: Properties of Siberian smoke plumes

NASA Astrophysics Data System (ADS)

Penning de Vries, Marloes; Beirle, Steffen; Sihler, Holger; Wagner, Thomas

2017-04-01

The UV Aerosol Index (UVAI) is a simple measure of aerosols from satellite that is particularly sensitive to elevated layers of absorbing particles. It has been determined from a range of instruments including TOMS, GOME-2, and OMI, for almost four decades and will be continued in the upcoming Sentinel missions S5-precursor, S4, and S5. Despite its apparent simplicity, the interpretation of UVAI is not straightforward, as it depends on aerosol abundance, absorption, and altitude in a non-linear way. In addition, UVAI depends on the geometry of the measurement (viewing angle, solar zenith and relative azimuth angles), particularly if viewing angles exceed 45 degrees, as is the case for OMI and TROPOMI (on S5-precursor). The dependence on scattering angle complicates the interpretation and further processing (e.g., averaging) of UVAI. In certain favorable cases, however, independent information on aerosol altitude and absorption may become available. We present a detailed study of the scatter angle dependence using SCIATRAN radiative transfer calculations. The model results were compared to observations of an extensive Siberian smoke plume, of which parts reached 10-12 km altitude. Due to its large extent and the high latitude, OMI observed the complete plume in five consecutive orbits under a wide range of scattering angles. This allowed us to deduce aerosol characteristics (absorption and layer height) that were compared with collocated CALIOP lidar measurements.

A multi-directional backlight for a wide-angle, glasses-free three-dimensional display.

PubMed

Fattal, David; Peng, Zhen; Tran, Tho; Vo, Sonny; Fiorentino, Marco; Brug, Jim; Beausoleil, Raymond G

2013-03-21

Multiview three-dimensional (3D) displays can project the correct perspectives of a 3D image in many spatial directions simultaneously. They provide a 3D stereoscopic experience to many viewers at the same time with full motion parallax and do not require special glasses or eye tracking. None of the leading multiview 3D solutions is particularly well suited to mobile devices (watches, mobile phones or tablets), which require the combination of a thin, portable form factor, a high spatial resolution and a wide full-parallax view zone (for short viewing distance from potentially steep angles). Here we introduce a multi-directional diffractive backlight technology that permits the rendering of high-resolution, full-parallax 3D images in a very wide view zone (up to 180 degrees in principle) at an observation distance of up to a metre. The key to our design is a guided-wave illumination technique based on light-emitting diodes that produces wide-angle multiview images in colour from a thin planar transparent lightguide. Pixels associated with different views or colours are spatially multiplexed and can be independently addressed and modulated at video rate using an external shutter plane. To illustrate the capabilities of this technology, we use simple ink masks or a high-resolution commercial liquid-crystal display unit to demonstrate passive and active (30 frames per second) modulation of a 64-view backlight, producing 3D images with a spatial resolution of 88 pixels per inch and full-motion parallax in an unprecedented view zone of 90 degrees. We also present several transparent hand-held prototypes showing animated sequences of up to six different 200-view images at a resolution of 127 pixels per inch.

Flow Behavior in Side-View Plane of Pitching Delta Wing

NASA Astrophysics Data System (ADS)

Pektas, Mehmet Can; Tasci, Mehmet Oguz; Karasu, Ilyas; Sahin, Besir; Akilli, Huseyin

2018-06-01

In the present investigation, a delta wing which has 70° sweep angle, Λ was oscillated on its midcord according to the equation of α(t)=αm+α0sin(ωet). This study focused on understanding the effect of pitching and characterizing the interaction of vortex breakdown with oscillating leading edges under different yaw angles, β over a slender delta wing. The value of mean angle of attack, αm was taken as 25°. The yaw angle, β was varied with an interval of 4° over the range of 0°≤β≤ 16°. The delta wing was sinusoidally pitched within the range of period of time 5s≤Te≤60s and reduced frequency was set as K=0.16, 0.25, 0.49, 1.96 and lastly amplitude of pitching motion was arranged as α0=±5°.Formations and locations of vortex breakdown were investigated by using the dye visualization technique in side view plane.

Multi-Angle Snowflake Camera Instrument Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuefer, Martin; Bailey, J.

2016-07-01

The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASCmore » cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.« less

Pair Production and Gamma-Ray Emission in the Outer Magnetospheres of Rapidly Spinning Young Pulsars

NASA Technical Reports Server (NTRS)

Ruderman, Malvin; Chen, Kaiyou

1997-01-01

Electron-positron pair production and acceleration in the outer magnetosphere may be crucial for a young rapidly spinning canonical pulsar to be a strong Gamma-ray emitter. Collision between curvature radiated GeV photons and soft X-ray photons seems to be the only efficient pair production mechanism. For Crib-like pulsars, the magnetic field near the light cylinder is so strong, such that the synchrotron radiation of secondary pairs will be in the needed X-ray range. However, for majority of the known Gamma-ray pulsars, surface emitted X-rays seem to work as the matches and fuels for a gamma-ray generation fireball in the outer magnetosphere. The needed X-rays could come from thermal emission of a cooling neutron star or could be the heat generated by bombardment of the polar cap by energetic particles generated in the outer magnetosphere. With detection of more Gamma-ray pulsars, it is becoming evident that the neutron star's intrisic geometry (the inclination angle between the rotation and magnetic axes) and observational geometry (the viewing angle with respect to the rotation axis) are crucial to the understanding of varieties of observational properties exhibited by these pulsars. Inclination angles for many known high energy Gamma-ray pulsars appear to be large and the distribution seems to be consistent with random orientation. However, all of them except Geminga are pre-selected from known radio pulsars. The viewing angles are thus limited to be around the respective inclination angles for beamed radio emission, which may induce strong selection effect. The viewing angles as well as the inclination angles of PSR 1509-58 and PSB 0656+14 may be small such that most of the high energy Gamma-rays produced in the outer accelerators may not reach the observer's direction. The observed Gamma-rays below 5 MeV from this pulsar may be synchrotron radiation of secondary electron-positron pairs produced outside the accelerating regions.

Limited-angle tomography for analyzer-based phase-contrast X-ray imaging

PubMed Central

Majidi, Keivan; Wernick, Miles N; Li, Jun; Muehleman, Carol; Brankov, Jovan G

2014-01-01

Multiple-Image Radiography (MIR) is an analyzer-based phase-contrast X-ray imaging method (ABI), which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume. PMID:24898008

Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

NASA Astrophysics Data System (ADS)

Majidi, Keivan; Wernick, Miles N.; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

2014-07-01

Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT-MIR only if one considers volumetric images near the central plane and not the whole volume.

Spectral bidirectional reflectance of Antarctic snow: Measurements and parameterization

NASA Astrophysics Data System (ADS)

Hudson, Stephen R.; Warren, Stephen G.; Brandt, Richard E.; Grenfell, Thomas C.; Six, Delphine

2006-09-01

The bidirectional reflectance distribution function (BRDF) of snow was measured from a 32-m tower at Dome C, at latitude 75°S on the East Antarctic Plateau. These measurements were made at 96 solar zenith angles between 51° and 87° and cover wavelengths 350-2400 nm, with 3- to 30-nm resolution, over the full range of viewing geometry. The BRDF at 900 nm had previously been measured at the South Pole; the Dome C measurement at that wavelength is similar. At both locations the natural roughness of the snow surface causes the anisotropy of the BRDF to be less than that of flat snow. The inherent BRDF of the snow is nearly constant in the high-albedo part of the spectrum (350-900 nm), but the angular distribution of reflected radiance becomes more isotropic at the shorter wavelengths because of atmospheric Rayleigh scattering. Parameterizations were developed for the anisotropic reflectance factor using a small number of empirical orthogonal functions. Because the reflectance is more anisotropic at wavelengths at which ice is more absorptive, albedo rather than wavelength is used as a predictor in the near infrared. The parameterizations cover nearly all viewing angles and are applicable to the high parts of the Antarctic Plateau that have small surface roughness and, at viewing zenith angles less than 55°, elsewhere on the plateau, where larger surface roughness affects the BRDF at larger viewing angles. The root-mean-squared error of the parameterized reflectances is between 2% and 4% at wavelengths less than 1400 nm and between 5% and 8% at longer wavelengths.

Smoke from Fires in Southern Mexico

NASA Technical Reports Server (NTRS)

2002-01-01

On May 2, 2002, numerous fires in southern Mexico sent smoke drifting northward over the Gulf of Mexico. These views from the Multi-angle Imaging SpectroRadiometer illustrate the smoke extent over parts of the Gulf and the southern Mexican states of Tabasco, Campeche and Chiapas. At the same time, dozens of other fires were also burning in the Yucatan Peninsula and across Central America. A similar situation occurred in May and June of 1998, when Central American fires resulted in air quality warnings for several U.S. States.

The image on the left is a natural color view acquired by MISR's vertical-viewing (nadir) camera. Smoke is visible, but sunglint in some ocean areas makes detection difficult. The middle image, on the other hand, is a natural color view acquired by MISR's 70-degree backward-viewing camera; its oblique view angle simultaneously suppresses sunglint and enhances the smoke. A map of aerosol optical depth, a measurement of the abundance of atmospheric particulates, is provided on the right. This quantity is retrieved using an automated computer algorithm that takes advantage of MISR's multi-angle capability. Areas where no retrieval occurred are shown in black.

The images each represent an area of about 380 kilometers x 1550 kilometers and were captured during Terra orbit 12616.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Airborne system for multispectral, multiangle polarimetric imaging.

PubMed

Bowles, Jeffrey H; Korwan, Daniel R; Montes, Marcos J; Gray, Deric J; Gillis, David B; Lamela, Gia M; Miller, W David

2015-11-01

In this paper, we describe the design, fabrication, calibration, and deployment of an airborne multispectral polarimetric imager. The motivation for the development of this instrument was to explore its ability to provide information about water constituents, such as particle size and type. The instrument is based on four 16 MP cameras and uses wire grid polarizers (aligned at 0°, 45°, 90°, and 135°) to provide the separation of the polarization states. A five-position filter wheel provides for four narrow-band spectral filters (435, 550, 625, and 750 nm) and one blocked position for dark-level measurements. When flown, the instrument is mounted on a programmable stage that provides control of the view angles. View angles that range to ±65° from the nadir have been used. Data processing provides a measure of the polarimetric signature as a function of both the view zenith and view azimuth angles. As a validation of our initial results, we compare our measurements, over water, with the output of a Monte Carlo code, both of which show neutral points off the principle plane. The locations of the calculated and measured neutral points are compared. The random error level in the measured degree of linear polarization (8% at 435) is shown to be better than 0.25%.

Musicking, embodiment and participatory enaction of music: outline and key points

NASA Astrophysics Data System (ADS)

Loaiza, Juan M.

2016-10-01

This paper proposes a way of understanding the confluence of the enactive approach to cognition and musicology in a wider sense. The implication is that existing socio-cultural approaches to meaning in music - whereby music is seen as a total social phenomenon, and the naturalistic view of music cognition may be articulated via the life-mind continuum proposed by enactivism. On the one hand, discussions on embodied music cognition are presented with the opportunity to overcome their de facto individualism in a principled, naturalistic way. On the other hand, for the socio-cultural-historical approaches the opportunity seems to be to move beyond the biology-culture divide without submitting to reductionism. A wider explanatory unit is presented. The explanatory utility of embodiment is examined in relation to the wider frame of social-life in dialectical fashion. A definition of musicking is sketched considering it as an instance of processes of social-life. This paper signals a direction to take, yet methodologies, results, and homologies with other disciplines are left open to further discussion.

3. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK WITH THE VAL TO THE RIGHT, LOOKING NORTHEAST. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Colorado

Atmospheric Science Data Center

2014-05-15

... the Multi-angle Imaging SpectroRadiometer (MISR). On the left, a natural-color view acquired by MISR's vertical-viewing (nadir) camera ... Gunnison River at the city of Grand Junction. The striking "L" shaped feature in the lower image center is a sandstone monocline known as ...

A cylindrical specimen holder for electron cryo-tomography

PubMed Central

Palmer, Colin M.; Löwe, Jan

2014-01-01

The use of slab-like flat specimens for electron cryo-tomography restricts the range of viewing angles that can be used. This leads to the “missing wedge” problem, which causes artefacts and anisotropic resolution in reconstructed tomograms. Cylindrical specimens provide a way to eliminate the problem, since they allow imaging from a full range of viewing angles around the tilt axis. Such specimens have been used before for tomography of radiation-insensitive samples at room temperature, but never for frozen-hydrated specimens. Here, we demonstrate the use of thin-walled carbon tubes as specimen holders, allowing the preparation of cylindrical frozen-hydrated samples of ribosomes, liposomes and whole bacterial cells. Images acquired from these cylinders have equal quality at all viewing angles, and the accessible tilt range is restricted only by the physical limits of the microscope. Tomographic reconstructions of these specimens demonstrate that the effects of the missing wedge are substantially reduced, and could be completely eliminated if a full tilt range was used. The overall quality of these tomograms is still lower than that obtained by existing methods, but improvements are likely in future. PMID:24275523

Reduction of skylight reflection effects in the above-water measurement of diffuse marine reflectance.

PubMed

Fougnie, B; Frouin, R; Lecomte, P; Deschamps, P Y

1999-06-20

Reflected skylight in above-water measurements of diffuse marine reflectance can be reduced substantially by viewing the surface through an analyzer transmitting the vertically polarized component of incident radiance. For maximum reduction of effects, radiometric measurements should be made at a viewing zenith angle of approximately 45 degrees (near the Brewster angle) and a relative azimuth angle between solar and viewing directions greater than 90 degrees (backscattering), preferably 135 degrees. In this case the residual reflected skylight in the polarized signal exhibits minimum sensitivity to the sea state and can be corrected to within a few 10(-4) in reflectance units. For most oceanic waters the resulting relative error on the diffuse marine reflectance in the blue and green is less than 1%. Since the water body polarizes incident skylight, the measured polarized reflectance differs from the total reflectance. The difference, however, is small for the considered geometry. Measurements made at the Scripps Institution of Oceanography pier in La Jolla, Calif., with a specifically designed scanning polarization radiometer, confirm the theoretical findings and demonstrate the usefulness of polarization radiometry for measuring diffuse marine reflectance.

Objective measurements for grading the nasal esthetics on Basal view in individuals with secondary cleft nasal deformity.

PubMed

He, Xing; Li, Hua; Shao, Yan; Shi, Bing

2015-01-01

The purpose of this study is to ascertain objective nasal measurements from the basal view that are predictive of nasal esthetics in individuals with secondary cleft nasal deformity. Thirty-three patients who had undergone unilateral cleft lip repair were retrospectively reviewed in this study. The degree of nasal deformity was subjectively ranked by seven surgeons using standardized basal-view measurements. Nine physical objective parameters including angles and ratios were measured. Correlations and regressions between these objective and subjective measurements were then analyzed. There was high concordance in subjective measurements by different surgeons (Kendall's harmonious coefficient = W = .825, P = .006). The strongest predictive factors for nasal aesthetics were the ratio of length of nasal alar (r = .370, P = .034) and the degree of deviation of the columnar axis (r = .451, P = .008). The columellar angle had a more powerful effect in rating nasal esthetics. There was reliable concordance in subjective ranking of nasal esthetics by surgeons. Measurement of the columnar angle may serve as an independent, objective predictor of esthetics of the nose.

View of the launch of STS 51-A shuttle Discovery

NASA Technical Reports Server (NTRS)

1984-01-01

View across the water of the launch of STS 51-A shuttle Discovery. The orbiter is just clearing the launch pad (90032); closer view of the Shuttle Discovery just clearing the launch pad. Photo was taken from across the river, with trees and shrubs forming the bottom edge of the view (90033); Low angle view of the rapidly climbing Discovery, still attached to its two solid rocket boosters and an external fuel tank (90034).

Position Estimation for Switched Reluctance Motor Based on the Single Threshold Angle

NASA Astrophysics Data System (ADS)

Zhang, Lei; Li, Pang; Yu, Yue

2017-05-01

This paper presents a position estimate model of switched reluctance motor based on the single threshold angle. In view of the relationship of between the inductance and rotor position, the position is estimated by comparing the real-time dynamic flux linkage with the threshold angle position flux linkage (7.5° threshold angle, 12/8SRM). The sensorless model is built by Maltab/Simulink, the simulation are implemented under the steady state and transient state different condition, and verified its validity and feasibility of the method..

Value of the fetal plantar shape in prenatal diagnosis of talipes equinovarus.

PubMed

Liao, Huifang; Cai, Ailu; Wang, Bing; Wang, Xiaoguang; Yan, Zhen; Li, Jingyu

2012-07-01

The purpose of this study was to evaluate the value of the fetal plantar shape in prenatal diagnosis of talipes equinovarus. A case-control study was conducted between September 2009 and February 2011. We measured the width and length of 249 feet (156 fetuses) included in this study and then calculated the width to length ratio. All of the fetuses were followed to obtain the pregnancy outcomes and confirm whether the deformity existed; then the bimalleolar angle of each foot with talipes equinovarus was measured. Independent samples t tests were performed to compare the foot width, length, and width to length ratio between normal and talipes equinovarus groups. We also assessed the correlation between the width to length ratio and bimalleolar angle in the talipes equinovarus cases with the Pearson correlation coefficient. Statistically significant differences were shown between the two groups (P< .001) for the three foot measurements, and a significant negative correlation was found between the width to length ratio and bimalleolar angle of the affected foot (r = -0.857). The fetal plantar shape can provide valuable information for prenatal diagnosis of clubfoot. Compared with a normal foot, a clubfoot tends to be wider and shorter. A higher width to length ratio is associated with a smaller bimalleolar angle and indicates a more severe talipes equinovarus deformity.

10. Elevation view of south side of FrankJensen Summer Home. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Elevation view of south side of Frank-Jensen Summer Home. Note that the steep angle of view gives an illusion of a flat roof. For a more accurate depiction of the roof line, see photos WA-207-4 and WA-207-8. - Frank-Jensen Summer Home, 17423 North Lake Shore Drive, Telma, Chelan County, WA

Structural design principles for self-assembled coordination polygons and polyhedra.

PubMed

Young, Neil J; Hay, Benjamin P

2013-02-18

Strategies for the design of ligands that combine with metal ions to form high-symmetry coordination assemblies are reviewed. Evaluation of crystal structure evidence reveals that prior design approaches, based on the concept of complementary bonding vector angles, fail to predict the majority of known examples. After explaining the reasons for this failure, it is shown how an alternative approach, de novo structure-based design, provides a practical method that predicts a much wider range of component shapes encoded to direct the formation of such assemblies.

Army Research Office and Air Force Office of Scientific Research Contractors’ Meeting in Chemical Propulsion Held in Arlington, Virginia on June 12-14, 2006

DTIC Science & Technology

2006-06-01

increasing the heat and mass transfer coefficients between the liquid phase and gas phase, (b) the spread of the spray over a wider angle [5], and the...counting. The density of the sample liquid in the vibrating tube is obtained from the resonant frequency of the vibrating system relative to the resonant...preparation of test gas mixtures of liquid fuels. We have compared the predictions of several current kinetic mechanisms for jet fuel and used these

An Empirical Function for Bidirectional Reflectance Characterization for Smoke Aerosols Using Multi-angular Airborne Measurements

NASA Astrophysics Data System (ADS)

Poudyal, R.; Singh, M. K.; Gatebe, C. K.; Gautam, R.; Varnai, T.

2015-12-01

Using airborne Cloud Absorption Radiometer (CAR) reflectance measurements of smoke, an empirical relationship between reflectances measured at different sun-satellite geometry is established, in this study. It is observed that reflectance of smoke aerosol at any viewing zenith angle can be computed using a linear combination of reflectance at two viewing zenith angles. One of them should be less than 30° and other must be greater than 60°. We found that the parameters of the linear combination computation follow a third order polynomial function of the viewing geometry. Similar relationships were also established for different relative azimuth angles. Reflectance at any azimuth angle can be written as a linear combination of measurements at two different azimuth angles. One must be in the forward scattering direction and the other in backward scattering, with both close to the principal plane. These relationships allowed us to create an Angular Distribution Model (ADM) for smoke, which can estimate reflectances in any direction based on measurements taken in four view directions. The model was tested by calculating the ADM parameters using CAR data from the SCAR-B campaign, and applying these parameters to different smoke cases at three spectral channels (340nm, 380nm and 470nm). We also tested our modelled smoke ADM formulas with Absorbing Aerosol Index (AAI) directly computed from the CAR data, based on 340nm and 380nm, which is probably the first study to analyze the complete multi-angular distribution of AAI for smoke aerosols. The RMSE (and mean error) of predicted reflectance for SCAR-B and ARCTAS smoke ADMs were found to be 0.002 (1.5%) and 0.047 (6%), respectively. The accuracy of the ADM formulation is also tested through radiative transfer simulations for a wide variety of situations (varying smoke loading, underlying surface types, etc.).

Activity Theory, Complexity and Sports Coaching: An Epistemology for a Discipline

ERIC Educational Resources Information Center

Jones, Robyn L.; Edwards, Christian; Filho, I. A. Tuim Viotto

2016-01-01

The aim of this article is twofold. First, it is to advance the case for activity theory (AT) as a credible and alternative lens to view and research sports coaching. Second, it is to position this assertion within the wider debate about the epistemology of coaching. Following a framing introduction, a more comprehensive review of the development…

Towards a Situative View of Extending and Scaling Innovations in Education: A Case Study of the "Six Learnings" Framework

ERIC Educational Resources Information Center

Lim, Kenneth Y. T.; Hung, David; Huang, Junsong

2011-01-01

This article seeks to draw from contemporary understandings of translation science to highlight and elaborate upon possible norms and procedures which the authors have found to be critical in the successful extension and scaling of design-based research interventions in education into wider practitioner-based adoption and adaptation. The impetus…

Implementation of an ICT-Based Learning Environment in a Nutrition Health Project

ERIC Educational Resources Information Center

Raiha, Teija; Tossavainen, Kerttu; Enkenberg, Jorma; Turunen, Hannele

2012-01-01

Purpose: The purpose of this study was to investigate the views of school staff on a nutrition health project implemented via an ICT-based learning environment in a secondary school (7th to 9th grades). Design/methodology/approach: The study was a part of the wider European Network for Health Promoting Schools programme (ENHPS; since 2008, Schools…

Telling Tales of Torture: Repositioning Young Adults' Views of Asylum Seekers

ERIC Educational Resources Information Center

Watts, Michael F.

2004-01-01

This paper explores the changing attitudes of a group of young adults towards asylum seekers in the UK. Based on the experience of sixth form students attending a workshop hosted by a former refugee from Pinochet's Chile, it argues for the importance of personal stories and their wider contexts and suggests that each is necessary to enable…

Technology Applications Report 1993

DTIC Science & Technology

1994-01-01

Companies Find Riches in Acousto-Optics 39 BMD Research Spurs Growth of Optics Start-Up 40 Improved Mirror Shaping Techniques to Correct Hubble...without destroying spectral bands along the horizon- tal axis. By developing toroidal mirrors that correct the vertical image, Chromex, Inc. was...which provide better image resolution and wider field-of-view than standard spherical-shaped mirrors , but are more difficult to make. PACE can

Code-Switching in the Primary Classroom: One Response to the Planned and the Unplanned Language Environment in Brunei [and] A Response.

ERIC Educational Resources Information Center

Martin, Peter W.; Espiritu, Clemencia C

1996-01-01

Examines how the teacher incorporates elements of both "Bahasa Melayu" and Brunei Malay into content lessons and views code switching in the primary classroom within the wider framework of community language norms and the linguistic pressures on students and teachers. Espiritu shares Martin's concern regarding the quantity and quality of…

"We Did the How to Teach It": Music Teaching and Learning in Higher Education in Australia

ERIC Educational Resources Information Center

Joseph, Dawn

2015-01-01

The Australian Government recognizes that the Arts are a critical part of formal school education and it should not be viewed as subordinate or extra. This paper forms part of a wider research project titled "Pre-service teacher attitudes and understandings of Music Education" that started in 2013. The focus of this paper investigates…

Nightlife Violence: A Gender-Specific View on Risk Factors for Violence in Nightlife Settings--A Cross-Sectional Study in Nine European Countries

ERIC Educational Resources Information Center

Schnitzer, Susanne; Bellis, Mark A.; Anderson, Zara; Hughes, Karen; Calafat, Amador; Juan, Montse; Kokkevi, Anna

2010-01-01

Within nightlife settings, youth violence places large burdens on both nightlife users and wider society. Internationally, research has identified risk factors for nightlife violence. However, few empirical studies have assessed differences in risk factors between genders. Here, a pan-European cross-sectional survey of 1,341 nightlife users aged…

On the Commodification of Science: The Programmatic Dimension

ERIC Educational Resources Information Center

de Oliveira, Marcos Barbosa

2013-01-01

The article is a partial result of a wider research project, in which the commodification of science is interpreted, from one point of view, as a facet of the rise of neoliberalism, and from another, as a set of processes, classified according to a three-category taxonomy. Only one of the taxonomy's categories is dealt with in this article,…

Apollo Portable Life Support System

NASA Image and Video Library

1968-06-11

S68-34582 (1968) --- With its exterior removed, the Apollo portable life support system (PLSS) can be easily studied. The PLSS is worn as a backpack over the Extravehicular Mobility Unit (EMU) a multi-layered spacesuit used for outside-the-spacecraft activity. JSC photographic frame no. S68-34582 is a wider view of the exposed interior working parts of the PLSS and its removed cover.

The Changing Nature and Definitions of Industrial Design and Implications for Prospective Undergraduate Students

ERIC Educational Resources Information Center

Goatman, Mike; Moody, Louise

2014-01-01

There are currently a wide range of Higher Education Industrial Design courses available in the UK. In the present era, a wider breadth of narrative has developed within the subject, and as a result the content of industrial design educational offerings varies considerably. The paper assesses the industry view of Industrial Design as a discipline…

MacIntyre's Revolutionary Aristotelian Philosophy and His Idea of an Educated Public Revisited

ERIC Educational Resources Information Center

Macallister, James

2016-01-01

In this article I revisit MacIntyre's lecture on the idea of an educated public. I argue that the full significance of MacIntyre's views on the underlying purposes of universities only become clear when his lecture on the educated public is situated in the context of his wider 'revolutionary Aristotelian' philosophical project. I claim that for…

The Future Is More than Just Tomorrow: Higher Education, the Economy and the Longer Term

ERIC Educational Resources Information Center

Crossick, Geoffrey

2010-01-01

In this commentary the author reflects on longer-term issues facing higher education in the context of recession and crisis in public finance. The views expressed are written from a personal perspective with the aim of stimulating and encouraging a wider and ongoing debate around the themes presented. The author draws upon the findings of three…

2. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VAL CAMERA CAR, VIEW OF CAMERA CAR AND TRACK WITH CAMERA STATION ABOVE LOOKING WEST TAKEN FROM RESERVOIR. - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Prediction of Viking lander camera image quality

NASA Technical Reports Server (NTRS)

Huck, F. O.; Burcher, E. E.; Jobson, D. J.; Wall, S. D.

1976-01-01

Formulations are presented that permit prediction of image quality as a function of camera performance, surface radiance properties, and lighting and viewing geometry. Predictions made for a wide range of surface radiance properties reveal that image quality depends strongly on proper camera dynamic range command and on favorable lighting and viewing geometry. Proper camera dynamic range commands depend mostly on the surface albedo that will be encountered. Favorable lighting and viewing geometries depend mostly on lander orientation with respect to the diurnal sun path over the landing site, and tend to be independent of surface albedo and illumination scattering function. Side lighting with low sun elevation angles (10 to 30 deg) is generally favorable for imaging spatial details and slopes, whereas high sun elevation angles are favorable for measuring spectral reflectances.

Dreamy Swirls on Saturn

NASA Image and Video Library

2017-09-12

NASA's Cassini spacecraft gazed toward the northern hemisphere of Saturn to spy subtle, multi-hued bands in the clouds there. This view looks toward the terminator -- the dividing line between night and day -- at lower left. The sun shines at low angles along this boundary, in places highlighting vertical structure in the clouds. Some vertical relief is apparent in this view, with higher clouds casting shadows over those at lower altitude. Images taken with the Cassini spacecraft narrow-angle camera using red, green and blue spectral filters were combined to create this natural-color view. The images were acquired on Aug. 31, 2017, at a distance of approximately 700,000 miles (1.1 million kilometers) from Saturn. Image scale is about 4 miles (6 kilometers) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21888

Viewing-zone control of integral imaging display using a directional projection and elemental image resizing method.

PubMed

Alam, Md Ashraful; Piao, Mei-Lan; Bang, Le Thanh; Kim, Nam

2013-10-01

Viewing-zone control of integral imaging (II) displays using a directional projection and elemental image (EI) resizing method is proposed. Directional projection of EIs with the same size of microlens pitch causes an EI mismatch at the EI plane. In this method, EIs are generated computationally using a newly introduced algorithm: the directional elemental image generation and resizing algorithm considering the directional projection geometry of each pixel as well as an EI resizing method to prevent the EI mismatch. Generated EIs are projected as a collimated projection beam with a predefined directional angle, either horizontally or vertically. The proposed II display system allows reconstruction of a 3D image within a predefined viewing zone that is determined by the directional projection angle.

Rotary acceleration of a subject inhibits choice reaction time to motion in peripheral vision

NASA Technical Reports Server (NTRS)

Borkenhagen, J. M.

1974-01-01

Twelve pilots were tested in a rotation device with visual simulation, alone and in combination with rotary stimulation, in experiments with variable levels of acceleration and variable viewing angles, in a study of the effect of S's rotary acceleration on the choice reaction time for an accelerating target in peripheral vision. The pilots responded to the direction of the visual motion by moving a hand controller to the right or left. Visual-plus-rotary stimulation required a longer choice reaction time, which was inversely related to the level of acceleration and directly proportional to the viewing angle.

Effects of soil and canopy characteristics on microwave backscattering of vegetation

NASA Technical Reports Server (NTRS)

Daughtry, C. S. T.; Ranson, K. J.

1991-01-01

A frequency modulated continuous wave C-band (4.8 GHz) scatterometer was mounted on an aerial lift truck and backscatter coefficients of corn were acquired as functions of polarizations, view angles, and row directions. As phytomass and green leaf area index increased, the backscatter also increased. Near anthesis when the canopies were fully developed, the major scattering elements were located in the upper 1 m of the 2.8 m tall canopy and little backscatter was measured below that level. C-band backscatter data could provide information to monitor vegetation at large view zenith angles.

16. SOUTH TO VIEW OF CIRCA 1900 MICHIGAN MACHINERY MFG. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. SOUTH TO VIEW OF CIRCA 1900 MICHIGAN MACHINERY MFG. CO. PUNCH PRESS WITH WOOD-BURNING HEATING STOVE LOCATED IN THE CENTER OF THE FACTORY BUILDING. BESIDE THE HEATING STOVE, POINTING TOWARD THE PUNCH PRESS, IS A JIG USED TO POSITION ANGLE STEEL COMPONENTS OF STEEL WINDMILL TOWER LEGS FOR PUNCHING BOLT HOLES. THE SUPPORT FOR THE BRICK FLUE OF THE HEATING STOVE IS CONSTRUCTED FROM SALVAGED GALVANIZED ANGLE STEEL OF THE TYPE USED IN FABRICATING WINDMILL TOWERS MANUFACTURED IN THE FACTORY. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

A Summer View of Russia's Lena Delta and Olenek

NASA Technical Reports Server (NTRS)

2004-01-01

These views of the Russian Arctic were acquired by NASA's Multi-angle Imaging SpectroRadiometer (MISR) instrument on July 11, 2004, when the brief arctic summer had transformed the frozen tundra and the thousands of lakes, channels, and rivers of the Lena Delta into a fertile wetland, and when the usual blanket of thick snow had melted from the vast plains and taiga forests. This set of three images cover an area in the northern part of the Eastern Siberian Sakha Republic. The Olenek River wends northeast from the bottom of the images to the upper left, and the top portions of the images are dominated by the delta into which the mighty Lena River empties when it reaches the Laptev Sea. At left is a natural color image from MISR's nadir (vertical-viewing) camera, in which the rivers appear murky due to the presence of sediment, and photosynthetically-active vegetation appears green. The center image is also from MISR's nadir camera, but is a false color view in which the predominant red color is due to the brightness of vegetation at near-infrared wavelengths. The most photosynthetically active parts of this area are the Lena Delta, in the lower half of the image, and throughout the great stretch of land that curves across the Olenek River and extends northeast beyond the relatively barren ranges of the Volyoi mountains (the pale tan-colored area to the right of image center).

The right-hand image is a multi-angle false-color view made from the red band data of the 60o backward, nadir, and 60o forward cameras, displayed as red, green and blue, respectively. Water appears blue in this image because sun glitter makes smooth, wet surfaces look brighter at the forward camera's view angle. Much of the landscape and many low clouds appear purple since these surfaces are both forward and backward scattering, and clouds that are further from the surface appear in a different spot for each view angle, creating a rainbow-like appearance. However, the vegetated region that is darker green in the natural color nadir image, also appears to exhibit a faint greenish hue in the multi-angle composite. A possible explanation for this subtle green effect is that the taiga forest trees (or dwarf-shrubs) are not too dense here. Since the the nadir camera is more likly to observe any gaps between the trees or shrubs, and since the vegetation is not as bright (in the red band) as the underlying soil or surface, the brighter underlying surface results in an area that is relatively brighter at the nadir view angle. Accurate maps of vegetation structural units are an essential part of understanding the seasonal exchanges of energy and water at the Earth's surface, and of preserving the biodiversity in these regions.

The Multiangle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82o north and 82o south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 24273. The panels cover an area of about 230 kilometers x 420 kilometers, and utilize data from blocks 30 to 34 within World Reference System-2 path 134.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Impact Angle and Time Control Guidance Under Field-of-View Constraints and Maneuver Limits

NASA Astrophysics Data System (ADS)

Shim, Sang-Wook; Hong, Seong-Min; Moon, Gun-Hee; Tahk, Min-Jea

2018-04-01

This paper proposes a guidance law which considers the constraints of seeker field-of-view (FOV) as well as the requirements on impact angle and time. The proposed guidance law is designed for a constant speed missile against a stationary target. The guidance law consists of two terms of acceleration commands. The first one is to achieve zero-miss distance and the desired impact angle, while the second is to meet the desired impact time. To consider the limits of FOV and lateral maneuver capability, a varying-gain approach is applied on the second term. Reduction of realizable impact times due to these limits is then analyzed by finding the longest course among the feasible ones. The performance of the proposed guidance law is demonstrated by numerical simulation for various engagement conditions.

Analysis of the restricting factors of laser countermeasure active detection technology

NASA Astrophysics Data System (ADS)

Zhang, Yufa; Sun, Xiaoquan

2016-07-01

The detection effect of laser active detection system is affected by various kinds of factors. In view of the application requirement of laser active detection, the influence factors for laser active detection are analyzed. The mathematical model of cat eye target detection distance has been built, influence of the parameters of laser detection system and the environment on detection range and the detection efficiency are analyzed. Various parameters constraint detection performance is simulated. The results show that the discovery distance of laser active detection is affected by the laser divergence angle, the incident angle and the visibility of the atmosphere. For a given detection range, the laser divergence angle and the detection efficiency are mutually restricted. Therefore, in view of specific application environment, it is necessary to select appropriate laser detection parameters to achieve optimal detection effect.

Aerosol Optical Depth Retrievals from High-Resolution Commercial Satellite Imagery Over Areas of High Surface Reflectance

DTIC Science & Technology

2006-06-01

angle Imaging SpectroRadiometer MODIS Moderate Resolution Imaging Spectroradiometer NGA National Geospatial Intelligence Agency POI Principles of...and µ , the cosine of the viewing zenith angle and the effect of the variation of each of these variables on total optical depth. Extraterrestrial ...Eq. (34). Additionally, solar zenith angle also plays a role in the third term on the RHS of Eq. (34) by modifying extraterrestrial spectral solar

Controls on stream network branching angles, tested using landscape evolution models

NASA Astrophysics Data System (ADS)

Theodoratos, Nikolaos; Seybold, Hansjörg; Kirchner, James W.

2016-04-01

Stream networks are striking landscape features. The topology of stream networks has been extensively studied, but their geometry has received limited attention. Analyses of nearly 1 million stream junctions across the contiguous United States [1] have revealed that stream branching angles vary systematically with climate and topographic gradients at continental scale. Stream networks in areas with wet climates and gentle slopes tend to have wider branching angles than in areas with dry climates or steep slopes, but the mechanistic linkages underlying these empirical correlations remain unclear. Under different climatic and topographic conditions different runoff generation mechanisms and, consequently, transport processes are dominant. Models [2] and experiments [3] have shown that the relative strength of channel incision versus diffusive hillslope transport controls the spacing between valleys, an important geometric property of stream networks. We used landscape evolution models (LEMs) to test whether similar factors control network branching angles as well. We simulated stream networks using a wide range of hillslope diffusion and channel incision parameters. The resulting branching angles vary systematically with the parameters, but by much less than the regional variability in real-world stream networks. Our results suggest that the competition between hillslope and channeling processes influences branching angles, but that other mechanisms may also be needed to account for the variability in branching angles observed in the field. References: [1] H. Seybold, D. H. Rothman, and J. W. Kirchner, 2015, Climate's watermark in the geometry of river networks, Submitted manuscript. [2] J. T. Perron, W. E. Dietrich, and J. W. Kirchner, 2008, Controls on the spacing of first-order valleys, Journal of Geophysical Research, 113, F04016. [3] K. E. Sweeney, J. J. Roering, and C. Ellis, 2015, Experimental evidence for hillslope control of landscape scale, Science, 349(6243), 51-53.

Low-cost rapid miniature optical pressure sensors for blast wave measurements.

PubMed

Wu, Nan; Wang, Wenhui; Tian, Ye; Zou, Xiaotian; Maffeo, Michael; Niezrecki, Christopher; Chen, Julie; Wang, Xingwei

2011-05-23

This paper presents an optical pressure sensor based on a Fabry-Perot (FP) interferometer formed by a 45° angle polished single mode fiber and an external silicon nitride diaphragm. The sensor is comprised of two V-shape grooves with different widths on a silicon chip, a silicon nitride diaphragm released on the surface of the wider V-groove, and a 45° angle polished single mode fiber. The sensor is especially suitable for blast wave measurements: its compact structure ensures a high spatial resolution; its thin diaphragm based design and the optical demodulation scheme allow a fast response to the rapid changing signals experienced during blast events. The sensor shows linearity with the correlation coefficient of 0.9999 as well as a hysteresis of less than 0.3%. The shock tube test demonstrated that the sensor has a rise time of less than 2 µs from 0 kPa to 140 kPa.

Spatial reflection patterns of iridescent wings of male pierid butterflies: curved scales reflect at a wider angle than flat scales.

PubMed

Pirih, Primož; Wilts, Bodo D; Stavenga, Doekele G

2011-10-01

The males of many pierid butterflies have iridescent wings, which presumably function in intraspecific communication. The iridescence is due to nanostructured ridges of the cover scales. We have studied the iridescence in the males of a few members of Coliadinae, Gonepteryx aspasia, G. cleopatra, G. rhamni, and Colias croceus, and in two members of the Colotis group, Hebomoia glaucippe and Colotis regina. Imaging scatterometry demonstrated that the pigmentary colouration is diffuse whereas the structural colouration creates a directional, line-shaped far-field radiation pattern. Angle-dependent reflectance measurements demonstrated that the directional iridescence distinctly varies among closely related species. The species-dependent scale curvature determines the spatial properties of the wing iridescence. Narrow beam illumination of flat scales results in a narrow far-field iridescence pattern, but curved scales produce broadened patterns. The restricted spatial visibility of iridescence presumably plays a role in intraspecific signalling.

New ways in creating pixelgram images

NASA Astrophysics Data System (ADS)

Malureanu, Radu; Di Fabrizio, Enzo

2006-09-01

Since the diffraction gratings were invented, their use in various security systems has been exploited. Their big advantage is the low production cost and, in the same time, the difficulty of replicating them. Most of the nowadays security systems are using those gratings to prove their originality. They can be seen on all the CDs, DVDs, most of the major credit cards and even on the wine bottles. In this article we present a new way of making such gratings without changing the production steps but generating an even more difficult to be replicated item. This new way consists not only in changing the grating period so that various false colours can be seen, but also their orientation so that for a complete check of the grating it should be seen under a certain solid angle. In the same time, one can also keep the possibility to change the grating period so this way various colours can be seen for each angle variation. By combining these two techniques (changing period and changing the angle ones) one can indeed create different images for each view angle and thus increasing the security of the object. In the same time, as can be seen, from the fabrication point of view no further complications appear. The production steps are identical, the only difference being the pattern. The resolution of the grating is not increased necessarily so neither from this point of view will complications appear.

Determination of optimum viewing angles for the angular normalization of land surface temperature over vegetated surface.

PubMed

Ren, Huazhong; Yan, Guangjian; Liu, Rongyuan; Li, Zhao-Liang; Qin, Qiming; Nerry, Françoise; Liu, Qiang

2015-03-27

Multi-angular observation of land surface thermal radiation is considered to be a promising method of performing the angular normalization of land surface temperature (LST) retrieved from remote sensing data. This paper focuses on an investigation of the minimum requirements of viewing angles to perform such normalizations on LST. The normally kernel-driven bi-directional reflectance distribution function (BRDF) is first extended to the thermal infrared (TIR) domain as TIR-BRDF model, and its uncertainty is shown to be less than 0.3 K when used to fit the hemispheric directional thermal radiation. A local optimum three-angle combination is found and verified using the TIR-BRDF model based on two patterns: the single-point pattern and the linear-array pattern. The TIR-BRDF is applied to an airborne multi-angular dataset to retrieve LST at nadir (Te-nadir) from different viewing directions, and the results show that this model can obtain reliable Te-nadir from 3 to 4 directional observations with large angle intervals, thus corresponding to large temperature angular variations. The Te-nadir is generally larger than temperature of the slant direction, with a difference of approximately 0.5~2.0 K for vegetated pixels and up to several Kelvins for non-vegetated pixels. The findings of this paper will facilitate the future development of multi-angular thermal infrared sensors.

Determination of Optimum Viewing Angles for the Angular Normalization of Land Surface Temperature over Vegetated Surface

PubMed Central

Ren, Huazhong; Yan, Guangjian; Liu, Rongyuan; Li, Zhao-Liang; Qin, Qiming; Nerry, Françoise; Liu, Qiang

2015-01-01

Multi-angular observation of land surface thermal radiation is considered to be a promising method of performing the angular normalization of land surface temperature (LST) retrieved from remote sensing data. This paper focuses on an investigation of the minimum requirements of viewing angles to perform such normalizations on LST. The normally kernel-driven bi-directional reflectance distribution function (BRDF) is first extended to the thermal infrared (TIR) domain as TIR-BRDF model, and its uncertainty is shown to be less than 0.3 K when used to fit the hemispheric directional thermal radiation. A local optimum three-angle combination is found and verified using the TIR-BRDF model based on two patterns: the single-point pattern and the linear-array pattern. The TIR-BRDF is applied to an airborne multi-angular dataset to retrieve LST at nadir (Te-nadir) from different viewing directions, and the results show that this model can obtain reliable Te-nadir from 3 to 4 directional observations with large angle intervals, thus corresponding to large temperature angular variations. The Te-nadir is generally larger than temperature of the slant direction, with a difference of approximately 0.5~2.0 K for vegetated pixels and up to several Kelvins for non-vegetated pixels. The findings of this paper will facilitate the future development of multi-angular thermal infrared sensors. PMID:25825975

General view of the flight deck of the Orbiter Discovery ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the flight deck of the Orbiter Discovery looking from a low angle up and aft from approximately behind the commander's station. In the view you can see the overhead aft observation windows, the payload operations work area and in this view the payload bay observation windows have protective covers on them. This view was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

A hands-free region-of-interest selection interface for solo surgery with a wide-angle endoscope: preclinical proof of concept.

PubMed

Jung, Kyunghwa; Choi, Hyunseok; Hong, Hanpyo; Adikrishna, Arnold; Jeon, In-Ho; Hong, Jaesung

2017-02-01

A hands-free region-of-interest (ROI) selection interface is proposed for solo surgery using a wide-angle endoscope. A wide-angle endoscope provides images with a larger field of view than a conventional endoscope. With an appropriate selection interface for a ROI, surgeons can also obtain a detailed local view as if they moved a conventional endoscope in a specific position and direction. To manipulate the endoscope without releasing the surgical instrument in hand, a mini-camera is attached to the instrument, and the images taken by the attached camera are analyzed. When a surgeon moves the instrument, the instrument orientation is calculated by an image processing. Surgeons can select the ROI with this instrument movement after switching from 'task mode' to 'selection mode.' The accelerated KAZE algorithm is used to track the features of the camera images once the instrument is moved. Both the wide-angle and detailed local views are displayed simultaneously, and a surgeon can move the local view area by moving the mini-camera attached to the surgical instrument. Local view selection for a solo surgery was performed without releasing the instrument. The accuracy of camera pose estimation was not significantly different between camera resolutions, but it was significantly different between background camera images with different numbers of features (P < 0.01). The success rate of ROI selection diminished as the number of separated regions increased. However, separated regions up to 12 with a region size of 160 × 160 pixels were selected with no failure. Surgical tasks on a phantom model and a cadaver were attempted to verify the feasibility in a clinical environment. Hands-free endoscope manipulation without releasing the instruments in hand was achieved. The proposed method requires only a small, low-cost camera and an image processing. The technique enables surgeons to perform solo surgeries without a camera assistant.

Optical Polarization of Light from a Sorghum Canopy Measured Under Both a Clear and an Overcast Sky

NASA Technical Reports Server (NTRS)

Vanderbilt, Vern; Daughtry, Craig; Biehl, Larry; Dahlgren, Robert

2014-01-01

Introduction: We tested the hypothesis that the optical polarization of the light reflected by a sorghum canopy is due to a Fresnel-type redirection, by sorghum leaf surfaces, of light from an unpolarized light source, the sun or overcast sky, toward the measuring sensor. If it can be shown that the source of the polarization of the light scattered by the sorghum canopy is a first surface, Fresnel-type reflection, then removing this surface reflected light from measurements of canopy reflectance presumably would allow better insight into the biochemical processes such as photosynthesis and metabolism that occur in the interiors of sorghum canopy leaves. Methods: We constructed a tower 5.9m tall in the center of a homogenous sorghum field. We equipped two Barnes MMR radiometers with polarization analyzers on the number 1, 3 and 7 Landsat TM wavelength bands. Positioning the radiometers atop the tower, we collected radiance data in 44 view directions on two days, one day with an overcast sky and the other, clear and sunlit. From the radiance data we calculated the linear polarization of the reflected light for each radiometer wavelength channel and view direction. Results and Discussion: Our experimental results support our hypothesis, showing that the amplitude of the linearly polarized portion of the light reflected by the sorghum canopy varied dramatically with view azimuth direction under a point source, the sun, but the amplitude varied little with view azimuth direction under the hemispherical source, the overcast sky. Under the clear sky, the angle of polarization depended upon the angle of incidence of the sunlight on the leaf, while under the overcast sky the angle of polarization depended upon the zenith view angle. These results support a polarized radiation transport model of the canopy that is based upon a first surface, Fresnel reflection from leaves in the sorghum canopy.

126. AERIAL FORWARD VIEW OF ENCLOSED HURRICANE BOW WITH FLIGHT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

126. AERIAL FORWARD VIEW OF ENCLOSED HURRICANE BOW WITH FLIGHT DECK GUN MOUNTS REMOVED AND ANGLED FLIGHT DECK. 1 OCTOBER 1956. (NATIONAL ARCHIVES NO. 80-G-1001445) - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

10. View northwest Typical panel detail (south chord) of variable ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. View northwest Typical panel detail (south chord) of variable section girder showing riveted connections, angle stiffeners for girder web, and nuts securing wind bracing rods. - Walpole-Westminster Bridge, Spanning Connecticut River between Walpole, NH & Westminster, VT, Walpole, Cheshire County, NH

Optic for industrial endoscope/borescope with narrow field of view and low distortion

DOEpatents

Stone, Gary F.; Trebes, James E.

2005-08-16

An optic for the imaging optics on the distal end of a flexible fiberoptic endoscope or rigid borescope inspection tool. The image coverage is over a narrow (<20 degrees) field of view with very low optical distortion (<5% pin cushion or barrel distortion), compared to the typical <20% distortion. The optic will permit non-contact surface roughness measurements using optical techniques. This optic will permit simultaneous collection of selected image plane data, which data can then be subsequently optically processed. The image analysis will yield non-contact surface topology data for inspection where access to the surface does not permit a mechanical styles profilometer verification of surface topology. The optic allows a very broad spectral band or range of optical inspection. It is capable of spectroscopic imaging and fluorescence induced imaging when a scanning illumination source is used. The total viewing angle for this optic is 10 degrees for the full field of view of 10 degrees, compared to 40-70 degrees full angle field of view of the conventional gradient index or GRIN's lens systems.

Faint F Ring and Prometheus

NASA Image and Video Library

2016-11-21

Surface features are visible on Saturn's moon Prometheus in this view from NASA's Cassini spacecraft. Most of Cassini's images of Prometheus are too distant to resolve individual craters, making views like this a rare treat. Saturn's narrow F ring, which makes a diagonal line beginning at top center, appears bright and bold in some Cassini views, but not here. Since the sun is nearly behind Cassini in this image, most of the light hitting the F ring is being scattered away from the camera, making it appear dim. Light-scattering behavior like this is typical of rings comprised of small particles, such as the F ring. This view looks toward the unilluminated side of the rings from about 14 degrees below the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 24, 2016. The view was acquired at a distance of approximately 226,000 miles (364,000 kilometers) from Prometheus and at a sun-Prometheus-spacecraft, or phase, angle of 51 degrees. Image scale is 1.2 miles (2 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20508

Usability of multiangular imaging spectroscopy data for analysis of vegetation canopy shadow fraction in boreal forest

NASA Astrophysics Data System (ADS)

Markiet, Vincent; Perheentupa, Viljami; Mõttus, Matti; Hernández-Clemente, Rocío

2016-04-01

Imaging spectroscopy is a remote sensing technology which records continuous spectral data at a very high (better than 10 nm) resolution. Such spectral images can be used to monitor, for example, the photosynthetic activity of vegetation. Photosynthetic activity is dependent on varying light conditions and varies within the canopy. To measure this variation we need very high spatial resolution data with resolution better than the dominating canopy element size (e.g., tree crown in a forest canopy). This is useful, e.g., for detecting photosynthetic downregulation and thus plant stress. Canopy illumination conditions are often quantified using the shadow fraction: the fraction of visible foliage which is not sunlit. Shadow fraction is known to depend on view angle (e.g., hot spot images have very low shadow fraction). Hence, multiple observation angles potentially increase the range of shadow fraction in the imagery in high spatial resolution imaging spectroscopy data. To investigate the potential of multi-angle imaging spectroscopy in investigating canopy processes which vary with shadow fraction, we obtained a unique multiangular airborne imaging spectroscopy data for the Hyytiälä forest research station located in Finland (61° 50'N, 24° 17'E) in July 2015. The main tree species are Norway spruce (Picea abies L. karst), Scots pine (Pinus sylvestris L.) and birch (Betula pubescens Ehrh., Betula pendula Roth). We used an airborne hyperspectral sensor AISA Eagle II (Specim - Spectral Imaging Ltd., Finland) mounted on a tilting platform. The tilting platform allowed us to measure at nadir and approximately 35 degrees off-nadir. The hyperspectral sensor has a 37.5 degrees field of view (FOV), 0.6m pixel size, 128 spectral bands with an average spectral bandwidth of 4.6nm and is sensitive in the 400-1000 nm spectral region. The airborne data was radiometrically, atmospherically and geometrically processed using the Parge and Atcor software (Re Se applications Schläpfer, Switzerland). However, even after meticulous geolocation, the canopy elements (needles) seen from the three view angles were different: at each overpass, different parts of the same crowns were observed. To overcome this, we used a 200m x 200m test site covered with pure pine stands. We assumed that for sunlit, shaded and understory spectral signatures are independent of viewing direction to the accuracy of a constant BRDF factor. Thus, we compared the spectral signatures for sunlit and shaded canopy and understory obtained for each view direction. We selected visually six hundred of the brightest and darkest canopy pixels. Next, we performed a minimum noise fraction (MNF) transformation, created a pixel purity index (PPI) and used Envi's n-D scatterplot to determine pure spectral signatures for the two classes. The pure endmembers for different view angles were compared to determine the BRDF factor and to analyze its spectral invariance. We demonstrate the compatibility of multi-angle data with high spatial resolution data. In principle, both carry similar information on structured (non-flat) targets thus as a vegetation canopy. Nevertheless, multiple view angles helped us to extend the range of shadow fraction in the images. Also, correct separation of shaded crown and shaded understory pixels remains a challenge.

Alpha and Omega

NASA Image and Video Library

2017-11-27

These two images illustrate just how far Cassini traveled to get to Saturn. On the left is one of the earliest images Cassini took of the ringed planet, captured during the long voyage from the inner solar system. On the right is one of Cassini's final images of Saturn, showing the site where the spacecraft would enter the atmosphere on the following day. In the left image, taken in 2001, about six months after the spacecraft passed Jupiter for a gravity assist flyby, the best view of Saturn using the spacecraft's high-resolution (narrow-angle) camera was on the order of what could be seen using the Earth-orbiting Hubble Space Telescope. At the end of the mission (at right), from close to Saturn, even the lower resolution (wide-angle) camera could capture just a tiny part of the planet. The left image looks toward Saturn from 20 degrees below the ring plane and was taken on July 13, 2001 in wavelengths of infrared light centered at 727 nanometers using the Cassini spacecraft narrow-angle camera. The view at right is centered on a point 6 degrees north of the equator and was taken in visible light using the wide-angle camera on Sept. 14, 2017. The view on the left was acquired at a distance of approximately 317 million miles (510 million kilometers) from Saturn. Image scale is about 1,900 miles (3,100 kilometers) per pixel. The view at right was acquired at a distance of approximately 360,000 miles (579,000 kilometers) from Saturn. Image scale is 22 miles (35 kilometers) per pixel. The Cassini spacecraft ended its mission on Sept. 15, 2017. https://photojournal.jpl.nasa.gov/catalog/PIA21353

Development and validation of a quantitative method to assess pedicle screw loosening in posterior spine instrumentation on plain radiographs.

PubMed

Aghayev, Emin; Zullig, Nicolas; Diel, Peter; Dietrich, Daniel; Benneker, Lorin M

2014-03-01

Currently, the diagnosis of pedicle screw (PS) loosening is based on a subjectively assessed halo sign, that is, a radiolucent line around the implant wider than 1 mm in plain radiographs. We aimed at development and validation of a quantitative method to diagnose PS loosening on radiographs. Between 11/2004 and 1/2010 36 consecutive patients treated with thoraco-lumbar spine fusion with PS instrumentation without PS loosening were compared with 37 other patients who developed a clinically manifesting PS loosening. Three different angles were measured and compared regarding their capability to discriminate the loosened PS over the postoperative course. The inter-observer invariance was tested and a receiver operating characteristics curve analysis was performed. The angle measured between the PS axis and the cranial endplate was significantly different between the early and all later postoperative images. The Spearman correlation coefficient for the measurements of two observers at each postoperative time point ranged between 0.89 at 2 weeks to 0.94 at 2 months and 1 year postoperative. The angle change of 1.9° between immediate postoperative and 6-month postoperative was 75% sensitive and 89% specific for the identification of loosened screws (AUC = 0.82). The angle between the PS axis and the cranial endplate showed good ability to change in PS loosening. A change of this angle of at least 2° had a relatively high sensitivity and specificity to diagnose screw loosening.

Looking at Ozone From a New Angle: Shuttle Ozone Limb Sounding Experiment-2 (SOLSE-2)

NASA Technical Reports Server (NTRS)

McPeters, Richard; Hilsenrath, Ernest; Janz, Scott; Brown, Tammy (Technical Monitor)

2002-01-01

The ozone layer above Earth is our planet's fragile sunscreen, protecting people, vegetation, and wildlife. NASA has been measuring ozone for more than 20 years by looking down, but SOLSE-2 will show that more information is available by looking at ozone from the side, at Earth's limb or atmospheric boundary. When the ozone layer is compromised, increased ultraviolet (UV) levels from the sun cause health problems ranging from severe sunburns to skin cancer and cataracts. A concerted global effort has been made to reduce or eliminate the production of chemicals that deplete ozone, but the ozone layer is not expected to recover for many decades because these chemicals can remain active in the atmosphere for up to 100 years. We know now that ozone monitoring needs to be focused in the lower stratosphere. The discovery of the ozone hole in 1985 demonstrated that very large changes in ozone were occurring in the lower stratosphere near 20 km, instead of the upper stratosphere as first expected, and where current ozone instruments are focused. Measuring ozone from a tangential perspective that is centered at the limb provides ozone profiles concentrated in the lower stratosphere. The first flight of SOLSE proved that this technique achieves the accuracy and coverage of traditional measurements, and surpasses the altitude resolution and depth of retrieval of conventional techniques. Results from the first flight convinced the science community to design the next generation ozone monitoring satellite based on SOLSE. The Ozone Mapping and Profiling Suite (OMPS) is currently being built for the NPOESS satellite. The primary objective of SOLSE-2 is to confirm the promising results of the first flight over a wider range of viewing conditions and spectral wavelengths. Sometimes a really hard problem can be solved when you look at it from a different angle! While scientists conduct research, protect yourself by observing the UV index and spend less unprotected time outdoors.

Locomotor damage in rats after X-irradiation in utero

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mullenix, Phyllis; Norton, Stata; Culver, Bruce

1975-08-01

Alterations in gait were found in rats after whole-body irradiation with 125 R on day 14, 15, and 16 of gestation. No effects on locomotion were detected after irradiation on day 17 with 125 R or after irradiation on day 14 with 50 R. A technique was set up for quantitative evaluation of locomotion based on a modification of other methods. Walking patterns of irradiated rats were recorded, when they were adults, by requiring them to walk up a 10$sup 0$ incline through a corridor after their feet had been dipped in ink. Rats irradiated on gestational day 14 hadmore » an in-phase, hopping gait with the sine of the angle between the hind feet and the direction of progression over 0.9. Rats irradiated on gestational days 15 and 16 had an alternating, waddling gait with wider stance and broader angle than control rats. Histologic examination of serial sections of the brains of these rats showed that the 14-day rats lacked all telencephalic commissures except for a few fibers which crossed in some rats. There was a progressive improvement in the condition of the anterior and ventral hippocampal commissures up to day 17, but the corpus callosum and doral hippocampal commissure were lacking or markedly reduced in all day 17 rats. No animals showed damage to the mesencephalic posterior commissure. Since rats which used the in-phase mode of locomotion were never observed to use alternating gait, the possible causal relationship of the commissural damage to the altered locomotor patterns was considered. In view of the restricted period of damage found for the anterior and ventral hippocampal commissures and the restriction of altered locomotion to damage in the same period, primary involvement of the corpus callosum and dorsal hippocampal commissure could be excluded, but a possible role for the other telencephalic commissures remained. (auth)« less

The attractive lip: A photomorphometric analysis.

PubMed

Penna, V; Fricke, A; Iblher, N; Eisenhardt, S U; Stark, G B

2015-07-01

Throughout literature, there are different parameters defining the ideal shape of the lip and lower third of the face. This study was conducted to clarify what it is that makes lips attractive - and whether there are gender-related differences of an attractive lip and lower third of the face. Pictures of the lip and chin region of 176 patients were photographed in a standardised way and evaluated by 250 voluntary judges through an internet presentation by means of an analogue Likert scaling system. We found a significant higher ratio of upper vermillion height/mouth-nose distance in frontal-view images of attractive compared to unattractive female (p < 0.001) and male (p < 0.05) perioral regions. Furthermore, the ratio of upper vermillion height/chin-nose distance was significantly higher in attractive than in unattractive female (p < 0.005) and male (p < 0.05) lip and chin regions. The nasolabial angle was significantly sharper in attractive compared to unattractive female perioral regions (p < 0.001). Moreover, attractive female lip and chin regions showed a wider mentolabial angle compared to unattractive female lip and chin regions (p < 0.05). Comparing men and women, we found that attractive female perioral regions showed a higher ratio of lower vermillion height/chin-mouth distance (p < 0.05) and lower vermillion height/chin-nose distance than attractive male perioral regions (p < 0.05). We were able to define certain parameters of the lip and lower third of the face that seem to add to the attractivity of female and male individuals and prove that there are gender-related differences in form and shape of an attractive lower third of the face. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Linkage between canopy water storage and drop size distributions of leaf drips

NASA Astrophysics Data System (ADS)

Nanko, Kazuki; Watanabe, Ai; Hotta, Norifumi; Suzuki, Masakazu

2013-04-01

Differences in drop size distribution (DSD) of leaf drips among tree species have been estimated and physically interpreted to clarify the leaf drip generation process. Leaf drip generation experiments for nine species were conducted in an indoor location without foliage vibration using an automatic mist spray. Broad-leaved species produced a similar DSD among species whose leaves had a matte surface and a second similar DSD among species whose leaves had a coated surface. The matte broad leaves produced a larger and wider range of DSDs than the coated broad leaves. Coated coniferous needles had a wider range of DSDs than the coated broad leaves and different DSDs were observed for different species. The species with shorter dense needles generated a larger DSD. The leaf drip diameter was calculated through the estimation of a state of equilibrium of a hanging drop on the leaves based on physical theory. The calculations indicated that the maximum diameter of leaf drips was determined by the contact angle, and the range of DSDs was determined by the variation in contact length and the contact diameter at the hanging points. The results revealed that leaf drip DSD changed due to variations in leaf hydrophobicity, leaf roughness, leaf geometry and leaf inclination among the different tree species. This study allows the modelization of throughfall DSD. Furthermore, it indicates the possibility of interpreting canopy water processes from canopy water storage to drainage through the contact angle and leaf drip DSD. The part of this study is published in Nanko et al. (2013, Agric. Forest. Meteorol. 169, 74-84).

Ash from Kilauea Eruption Viewed by NASA's MISR

NASA Image and Video Library

2018-05-09

On May 3, 2018, a new eruption began at a fissure of the Kilauea volcano on the Island of Hawaii. Kilauea is the most active volcano in the world, having erupted almost continuously since 1983. Advancing lava and dangerous sulfur dioxide gas have forced thousands of residents in the neighborhood of Leilani Estates to evacuate. A number of homes have been destroyed, and no one can say how soon the eruption will abate and evacuees can return home. On May 6, 2018, at approximately 11 a.m. local time, the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite captured this view of the island as it passed overhead. Much of the island was shrouded by clouds, including the fissure on its eastern point. However, an eruption plume is visible streaming southwest over the ocean. The MISR instrument is unique in that it has nine cameras that view Earth at different angles: one pointing downward, four at various angles in the forward direction, and four in the backward direction. This image shows the view from one of MISR's forward-pointing cameras (60 degrees), which shows the plume more distinctly than the near-vertical views. The information from the images acquired at different view angles is used to calculate the height of the plume, results of which are superimposed on the right-hand image. The top of the plume near the fissure is at approximately 6,500 feet (2,000 meters) altitude, and the height of the plume decreases as it travels south and west. These relatively low altitudes mean that the ash and sulfur dioxide remained near the ground, which can cause health issues for people on the island downwind of the eruption. The "Ocean View" air quality monitor operated by the Clean Air Branch of the State of Hawaii Department of Health recorded a concentration of 18 μg/m3 of airborne particles less than 2.5 micrometers in diameter at 11 a.m. local time. This amount corresponds to an air quality rating of "moderate" and supports the MISR results indicating that ash was most likely present at ground level on this side of the island. These data were acquired during Terra orbit 97780. An annotated version is available at https://photojournal.jpl.nasa.gov/catalog/PIA22451

Be Masters in that You Teach and Continue to Learn: Medieval Muslim Thinkers on Educational Theory

ERIC Educational Resources Information Center

Gunther, Sebastian

2006-01-01

This article is dedicated to shedding light on a spectrum of issues in educational thought in Islam, which may--due to their universal relevance--be of interest not only to specialists but also to a wider readership. It also provides an idea of the educational views and philosophies advocated by some great medieval Muslim thinkers which offer…

We Cannot Continue as We Are: The Educator in an Education for Survival

ERIC Educational Resources Information Center

Moss, Peter

2010-01-01

The article takes a broad view, locating discussion about the early years educator in a wider debate about the future of the educator at a time of great crisis, when even the future of our species is in question. The state we are in calls for fundamental review of the purposes and concept of education and, therefore, the values, qualities and…

Range Estimation Algorithm Comparison in 3-D Flash LADAR Data

DTIC Science & Technology

2009-03-01

formed from LADAR intensity data viewed at sample 10. Target is about 70 meters from receiver and normal to line of sight. White square indicates region...that when averaged form a pulse that is slightly wider than the individual returns. . . . . . . . 35 4.1 Examples of simulated LADAR waveforms of...varying widths used for PWE tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 4.2 Simulated noiseless data buffered through LADAR sytem

"What Does the Term Critical Thinking Mean to You?" A Qualitative Analysis of Chemistry Undergraduate, Teaching Staff and Employers' Views of Critical Thinking

ERIC Educational Resources Information Center

Danczak, S. M.; Thompson, C. D.; Overton, T. L.

2017-01-01

Good critical thinking is important to the development of students and a valued skill in commercial markets and wider society. There has been much discussion regarding the definition of critical thinking and how it is best taught in higher education. This discussion has generally occurred between philosophers, cognitive psychologists and education…

Impact of Changes to Practical Assessment at GCSE and A-Level: The Start of a Longitudinal Study by OCR

ERIC Educational Resources Information Center

Wilson, Frances; Wade, Neil; Evans, Steve

2016-01-01

As part of a wider qualification reform at upper secondary level in England, the assessment of practical work is changing, following concerns that the legacy model of assessment was having a negative impact on teaching and learning. The OCR examination board is running a longitudinal survey of teachers' views on practical work, focusing on the…

Demonstration of a Corner-cube-interferometer LWIR Hyperspectral Imager

NASA Astrophysics Data System (ADS)

Renhorn, Ingmar G. E.; Svensson, Thomas; Cronström, Staffan; Hallberg, Tomas; Persson, Rolf; Lindell, Roland; Boreman, Glenn D.

2010-01-01

An interferometric long-wavelength infrared (LWIR) hyperspectral imager is demonstrated, based on a Michelson corner-cube interferometer. This class of system is inherently mechanically robust, and should have advantages over Sagnac-interferometer systems in terms of relaxed beamsplitter-coating specifications, and wider unvignetted field of view. Preliminary performance data from the laboratory prototype system are provided regarding imaging, spectral resolution, and fidelity of acquired spectra.

A Description of a Family of Heron Quadrilaterals

ERIC Educational Resources Information Center

Sastry, K. R. S.

2005-01-01

Mathematical historians place Heron in the first century. Right-angled triangles with integer sides and area had been determined before Heron, but he discovered such a "non" right-angled triangle, viz 13, 14, 15; 84. In view of this, triangles with integer sides and area are named "Heron triangles." The Indian mathematician Brahmagupta, born in…

Highlighting Titan's Hazes

NASA Image and Video Library

2017-08-11

NASA's Cassini spacecraft looks toward the night side of Saturn's moon Titan in a view that highlights the extended, hazy nature of the moon's atmosphere. During its long mission at Saturn, Cassini has frequently observed Titan at viewing angles like this, where the atmosphere is backlit by the Sun, in order to make visible the structure of the hazes. Titan's high-altitude haze layer appears blue here, whereas the main atmospheric haze is orange. The difference in color could be due to particle sizes in the haze. The blue haze likely consists of smaller particles than the orange haze. Images taken using red, green and blue spectral filters were combined to create this natural-color view. The image was taken with the Cassini spacecraft narrow-angle camera on May 29, 2017. The view was acquired at a distance of approximately 1.2 million miles (2 million kilometers) from Titan. Image scale is 5 miles (9 kilometers) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21625

Dual-view-zone tabletop 3D display system based on integral imaging.

PubMed

He, Min-Yang; Zhang, Han-Le; Deng, Huan; Li, Xiao-Wei; Li, Da-Hai; Wang, Qiong-Hua

2018-02-01

In this paper, we propose a dual-view-zone tabletop 3D display system based on integral imaging by using a multiplexed holographic optical element (MHOE) that has the optical properties of two sets of microlens arrays. The MHOE is recorded by a reference beam using the single-exposure method. The reference beam records the wavefronts of a microlens array from two different directions. Thus, when the display beam is projected on the MHOE, two wavefronts with the different directions will be rebuilt and the 3D virtual images can be reconstructed in two viewing zones. The MHOE has angle and wavelength selectivity. Under the conditions of the matched wavelength and the angle of the display beam, the diffraction efficiency of the MHOE is greatest. Because the unmatched light just passes through the MHOE, the MHOE has the advantage of a see-through display. The experimental results confirm the feasibility of the dual-view-zone tabletop 3D display system.

Influence of Fiber Orientation on Single-Point Cutting Fracture Behavior of Carbon-Fiber/Epoxy Prepreg Sheets.

PubMed

Wei, Yingying; An, Qinglong; Cai, Xiaojiang; Chen, Ming; Ming, Weiwei

2015-10-02

The purpose of this article is to investigate the influences of carbon fibers on the fracture mechanism of carbon fibers both in macroscopic view and microscopic view by using single-point flying cutting method. Cutting tools with three different materials were used in this research, namely, PCD (polycrystalline diamond) tool, CVD (chemical vapor deposition) diamond thin film coated carbide tool and uncoated carbide tool. The influence of fiber orientation on the cutting force and fracture topography were analyzed and conclusions were drawn that cutting forces are not affected by cutting speeds but significantly influenced by the fiber orientation. Cutting forces presented smaller values in the fiber orientation of 0/180° and 15/165° but the highest one in 30/150°. The fracture mechanism of carbon fibers was studied in different cutting conditions such as 0° orientation angle, 90° orientation angle, orientation angles along fiber direction, and orientation angles inverse to the fiber direction. In addition, a prediction model on the cutting defects of carbon fiber reinforced plastic was established based on acoustic emission (AE) signals.

Influence of Fiber Orientation on Single-Point Cutting Fracture Behavior of Carbon-Fiber/Epoxy Prepreg Sheets

PubMed Central

Wei, Yingying; An, Qinglong; Cai, Xiaojiang; Chen, Ming; Ming, Weiwei

2015-01-01

The purpose of this article is to investigate the influences of carbon fibers on the fracture mechanism of carbon fibers both in macroscopic view and microscopic view by using single-point flying cutting method. Cutting tools with three different materials were used in this research, namely, PCD (polycrystalline diamond) tool, CVD (chemical vapor deposition) diamond thin film coated carbide tool and uncoated carbide tool. The influence of fiber orientation on the cutting force and fracture topography were analyzed and conclusions were drawn that cutting forces are not affected by cutting speeds but significantly influenced by the fiber orientation. Cutting forces presented smaller values in the fiber orientation of 0/180° and 15/165° but the highest one in 30/150°. The fracture mechanism of carbon fibers was studied in different cutting conditions such as 0° orientation angle, 90° orientation angle, orientation angles along fiber direction, and orientation angles inverse to the fiber direction. In addition, a prediction model on the cutting defects of carbon fiber reinforced plastic was established based on acoustic emission (AE) signals. PMID:28793597

Young people's views about the purpose and composition of research ethics committees: findings from the PEARL qualitative study.

PubMed

Audrey, Suzanne; Brown, Lindsey; Campbell, Rona; Boyd, Andy; Macleod, John

2016-09-02

Avon Longitudinal Study of Parents and Children (ALSPAC) is a birth cohort study within which the Project to Enhance ALSPAC through Record Linkage (PEARL) was established to enrich the ALSPAC resource through linkage between ALSPAC participants and routine sources of health and social data. PEARL incorporated qualitative research to seek the views of young people about data linkage, including their opinions about appropriate safeguards and research governance. In this paper we focus on views expressed about the purpose and composition of research ethics committees. Digitally recorded interviews were conducted with 48 participants aged 17-19 years. Participants were asked about whether medical research should be monitored and controlled, their knowledge of research ethics committees, who should sit on these committees and what their role should be. Interview recordings were fully transcribed and anonymised. Thematic analysis was undertaken, assisted by the Framework approach to data management. The majority of interviewees had little or no specific knowledge of ethics committees. Once given basic information about research ethics committees, only three respondents suggested there was no need for such bodies to scrutinise research. The key tasks of ethics committees were identified as monitoring the research process and protecting research participants. The difficulty of balancing the potential to inhibit research against the need to protect research participants was acknowledged. The importance of relevant research and professional expertise was identified but it was also considered important to represent wider public opinion, and to counter the bias potentially associated with self-selection possibly through a selection process similar to 'jury duty'. There is a need for more education and public awareness about the role and composition of research ethics committees. Despite an initial lack of knowledge, interviewees were able to contribute their ideas and balance the rights of individuals with the wider benefits from research. The suggestion that public opinion should be represented through random selection similar to jury duty may be worth pursuing in the light of the need to ensure diversity of opinion and establish trust amongst the general public about the use of 'big data' for the wider public good.

Spinning angle optical calibration apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, S.K.; Pratt, H.R.

1991-02-26

This patent describes an optical calibration apparatus provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning magic angles in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the magic angle of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to amore » graduation or graduations on a reticle in the magnifying scope is noted.« less

Optical parameters of TN display with dichroic dye

NASA Astrophysics Data System (ADS)

Olifierczuk, Marek; Zielinski, Jerzy; Perkowski, Pawel

2000-05-01

The present work contain the studies on optical parameters (contrast ratio, viewing angle, birefringence and brightness) of twisted nematic display with black dichroic dye which is designed for an application in large-area information and advertising systems. The numerical optimization of display with a dye has been done. The absorption characteristic of the dye has been obtained. Birefringence of doped mixtures (Delta) n has been measured. The contrast ratio of doped mixtures has been measured in wide temperature range from -25 degree(s)C to +70 degree(s)C. The angle characteristics of contrast ratio for +20 degree(s)C have been obtained. In the work the detailed results describing the effect of a dye on temperature dependence of birefringence and contrast ratio, moreover, the effect of dye on the viewing angle for the first and second transmission minimum will be presented. Additionally, the dielectric characteristics of different mixtures will be shown.

A wide-angle camera module for disposable endoscopy

NASA Astrophysics Data System (ADS)

Shim, Dongha; Yeon, Jesun; Yi, Jason; Park, Jongwon; Park, Soo Nam; Lee, Nanhee

2016-08-01

A wide-angle miniaturized camera module for disposable endoscope is demonstrated in this paper. A lens module with 150° angle of view (AOV) is designed and manufactured. All plastic injection-molded lenses and a commercial CMOS image sensor are employed to reduce the manufacturing cost. The image sensor and LED illumination unit are assembled with a lens module. The camera module does not include a camera processor to further reduce its size and cost. The size of the camera module is 5.5 × 5.5 × 22.3 mm3. The diagonal field of view (FOV) of the camera module is measured to be 110°. A prototype of a disposable endoscope is implemented to perform a pre-clinical animal testing. The esophagus of an adult beagle dog is observed. These results demonstrate the feasibility of a cost-effective and high-performance camera module for disposable endoscopy.

SSPX thermistor system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomassen, K I

The SSPX Thermistor is a glass encapsulated bead thermistor made by Thermometrics, a BR 14 P A 103 J. The BR means ruggedized bead structure, 14 is the nominal bead diameter in mils, P refers to opposite end leads, A is the material system code letter, 103 refers to its 10 k{Omega} zero-power resistance at 25 C, and the tolerance letter J indicates {+-} 5% at 25 C. It is football shaped, with height ->, and is viewed through a slot of height h = 0.01 inches. The slot is perpendicular to the long axis of the bead, and ismore » a distance s {approx} 0.775 cm in front of the thermistor. So plasma is viewed over a large angle along the slot, but over a small angle {alpha} perpendicular to the slot. The angle {alpha} is given by 2s tan{alpha} = -> + h.« less

Maneuver Algorithm for Bearings-Only Target Tracking with Acceleration and Field of View Constraints

NASA Astrophysics Data System (ADS)

Roh, Heekun; Shim, Sang-Wook; Tahk, Min-Jea

2018-05-01

This paper proposes a maneuver algorithm for the agent performing target tracking with bearing angle information only. The goal of the agent is to estimate the target position and velocity based only on the bearing angle data. The methods of bearings-only target state estimation are outlined. The nature of bearings-only target tracking problem is then addressed. Based on the insight from above-mentioned properties, the maneuver algorithm for the agent is suggested. The proposed algorithm is composed of a nonlinear, hysteresis guidance law and the estimation accuracy assessment criteria based on the theory of Cramer-Rao bound. The proposed guidance law generates lateral acceleration command based on current field of view angle. The accuracy criteria supply the expected estimation variance, which acts as a terminal criterion for the proposed algorithm. The aforementioned algorithm is verified with a two-dimensional simulation.

Apparatus and method for high dose rate brachytherapy radiation treatment

DOEpatents

Macey, Daniel J.; Majewski, Stanislaw; Weisenberger, Andrew G.; Smith, Mark Frederick; Kross, Brian James

2005-01-25

A method and apparatus for the in vivo location and tracking of a radioactive seed source during and after brachytherapy treatment. The method comprises obtaining multiple views of the seed source in a living organism using: 1) a single PSPMT detector that is exposed through a multiplicity of pinholes thereby obtaining a plurality of images from a single angle; 2) a single PSPMT detector that may obtain an image through a single pinhole or a plurality of pinholes from a plurality of angles through movement of the detector; or 3) a plurality of PSPMT detectors that obtain a plurality of views from different angles simultaneously or virtually simultaneously. The plurality of images obtained from these various techniques, through angular displacement of the various acquired images, provide the information required to generate the three dimensional images needed to define the location of the radioactive seed source within the body of the living organism.

Objective for monitoring the corona discharge

NASA Astrophysics Data System (ADS)

Obrezkov, Andrey; Rodionov, Andrey Yu.; Pisarev, Viktor N.; Chivanov, Alexsey N.; Baranov, Yuri P.; Korotaev, Valery V.

2016-04-01

Remote optoelectronic probing is one of the most actual aspects of overhead electric line maintenances. By installing such systems on a helicopter (for example) it becomes possible to monitor overhead transmission line status and to search damaged parts of the lines. Thermal and UV-cameras are used for more effective diagnostic. UV-systems are fitted with filters, that attenuate visible spectrum, which is an undesired type of signal. Also these systems have a wide view angle for better view and proper diagnostics. For even more effectiveness, it is better to use several spectral channels: like UV and IR. Such spectral selection provides good noise reduction. Experimental results of spectral parameters of the wide view angle multispectral objective for such systems are provided in this report. There is also data on point spread function, UV and IR scattering index data and technical requirements for detectors.

Height and Motion of the Chikurachki Eruption Plume

NASA Technical Reports Server (NTRS)

2003-01-01

The height and motion of the ash and gas plume from the April 22, 2003, eruption of the Chikurachki volcano is portrayed in these views from the Multi-angle Imaging SpectroRadiometer (MISR). Situated within the northern portion of the volcanically active Kuril Island group, the Chikurachki volcano is an active stratovolcano on Russia's Paramushir Island (just south of the Kamchatka Peninsula).

In the upper panel of the still image pair, this scene is displayed as a natural-color view from MISR's vertical-viewing (nadir) camera. The white and brownish-grey plume streaks several hundred kilometers from the eastern edge of Paramushir Island toward the southeast. The darker areas of the plume typically indicate volcanic ash, while the white portions of the plume indicate entrained water droplets and ice. According to the Kamchatkan Volcanic Eruptions Response Team (KVERT), the temperature of the plume near the volcano on April 22 was -12o C.

The lower panel shows heights derived from automated stereoscopic processing of MISR's multi-angle imagery, in which the plume is determined to reach heights of about 2.5 kilometers above sea level. Heights for clouds above and below the eruption plume were also retrieved, including the high-altitude cirrus clouds in the lower left (orange pixels). The distinctive patterns of these features provide sufficient spatial contrast for MISR's stereo height retrieval to perform automated feature matching between the images acquired at different view angles. Places where clouds or other factors precluded a height retrieval are shown in dark gray.

The multi-angle 'fly-over' animation (below) allows the motion of the plume and of the surrounding clouds to be directly observed. The frames of the animation consist of data acquired by the 70-degree, 60-degree, 46-degree and 26-degree forward-viewing cameras in sequence, followed by the images from the nadir camera and each of the four backward-viewing cameras, ending with the view from the 70-degree backward camera.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 17776. The panels cover an area of approximately 296 kilometers x 216 kilometers (still images) and 185 kilometers x 154 kilometers (animation), and utilize data from blocks 50 to 51 within World Reference System-2 path 100.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

[figure removed for brevity, see original site

Unveiling the nature of the  $$\\gamma$$-ray emitting active galactic nucleus PKS 0521-36

DOE PAGES

D'Ammando, F.; Orienti, M.; Tavecchio, F.; ...

2015-05-19

PKS 0521-36 is an active galactic nucleus (AGN) with uncertain classification. Here, we investigate the properties of this source from radio to γ-rays. The broad emission lines in the optical and ultraviolet bands and steep radio spectrum indicate a possible classification as an intermediate object between broad-line radio galaxies (BLRG) and steep spectrum radio quasars (SSRQ). On pc-scales PKS 0521-36 shows a knotty structure similar to misaligned AGN. The core dominance and the γ-ray properties are similar to those estimated for other SSRQ and BLRG detected in γ-rays, suggesting an intermediate viewing angle with respect to the observer. In thismore » context the flaring activity detected from this source by Fermi-Large Area Telescope between 2010 June and 2012 February is very intriguing. We discuss the γ-ray emission of this source in the framework of the structured jet scenario, comparing the spectral energy distribution (SED) of the flaring state in 2010 June with that of a low state. We present three alternative models corresponding to three different choices of the viewing angles θv = 6°, 15°, and 20°. We obtain a good fit for the first two cases, but the SED obtained with θv = 15° if observed at a small angle does not resemble that of a typical blazar since the synchrotron emission should dominate by a large factor (~100) the inverse Compton component. This suggests that a viewing angle between 6° and 15° is preferred, with the rapid variability observed during γ-ray flares favouring a smaller angle. However, we cannot rule out that PKS 0521-36 is the misaligned counterpart of a synchrotron-dominated blazar.« less

Angular Normalization of Ground and Satellite Observations of Sun-induced Chlorophyll Fluorescence for Assessing Vegetation Productivity

NASA Astrophysics Data System (ADS)

Chen, J. M.; He, L.; Chou, S.; Ju, W.; Zhang, Y.; Joiner, J.; Liu, J.; Mo, G.

2017-12-01

Sun-induced chlorophyll fluorescence (SIF) measured from plant canopies originates mostly from sunlit leaves. Observations of SIF by satellite sensors, such as GOME-2 and GOSAT, are often made over large view zenith angle ranges, causing large changes in the viewed sunlit leaf fraction across the scanning swath. Although observations made by OCO-2 are near nadir, the observed sunlit leaf fraction could still vary greatly due to changes in the solar zenith angle with latitude and time of overpass. To demonstrate the importance of considering the satellite-target-view geometry in using SIF for assessing vegetation productivity, we conducted multi-angle measurements of SIF using a hyperspectral sensor mounted on an automated rotating system over a rice field near Nanjing, China. A method is developed to separate SIF measurements at each angle into sunlit and shaded leaf components, and an angularly normalized canopy-level SIF is obtained as the weighted sum of sunlit and shaded SIF. This normalized SIF is shown to be a much better proxy of GPP of the rice field measured by an eddy covariance system than the unnormalized SIF observations. The same normalization scheme is also applied to the far-red GOME-2 SIF observations on sunny days, and we found that the normalized SIF is better correlated with model-simulated GPP than the original SIF observations. The coefficient of determination (R2) is improved by 0.07±0.04 on global average using the normalization scheme. The most significant improvement in R2 by 0.09±0.04 is found in deciduous broadleaf forests, where the observed sunlit leaf fraction is highly sensitive to solar zenith angle.

Scleral Buckling Using a Non-contact Wide-Angle Viewing System with a 25-Gauge Chandelier Endoilluminator.

PubMed

Jo, Jaehyuck; Moon, Byung Gil; Lee, Joo Yong

2017-12-01

To report the outcome of scleral buckling using a non-contact wide-angle viewing system with a 25-gauge chandelier endoilluminator. Retrospective analyses of medical records were performed for 17 eyes of 16 patients with primary rhegmatogenous retinal detachment (RRD) without proliferative vitreoretinopathy who had undergone conventional scleral buckling with cryoretinopexy using the combination of a non-contact wide-angle viewing system and chandelier endoillumination. The patients were eight males and five females with a mean age of 26.8 ± 10.2 (range, 11 to 47) years. The mean follow-up period was 7.3 ± 3.1 months. Baseline best-corrected visual acuity was 0.23 ± 0.28 logarithm of the minimum angle of resolution units. Best-corrected visual acuity at the final visit showed improvement (0.20 ± 0.25 logarithm of the minimum angle of resolution units), but the improvement was not statistically significant (p = 0.722). As a surgery-related complication, there was vitreous loss at the end of surgery in one eye. As a postoperative complication, increased intraocular pressure (four cases) and herpes simplex epithelial keratitis (one case) were controlled postoperatively with eye drops. One case of persistent RRD after primary surgery needed additional vitrectomy, and the retina was postoperatively attached. Scleral buckling with chandelier illumination as a surgical technique for RRD has the advantages of relieving the surgeon's neck pain from prolonged use of the indirect ophthalmoscope and sharing the surgical procedure with another surgical team member. In addition, fine retinal breaks that are hard to identify using an indirect ophthalmoscope can be easily found under the microscope by direct endoillumination. © 2017 The Korean Ophthalmological Society

Reproducibility and Angle Independence of Electromechanical Wave Imaging for the Measurement of Electromechanical Activation during Sinus Rhythm in Healthy Humans.

PubMed

Melki, Lea; Costet, Alexandre; Konofagou, Elisa E

2017-10-01

Electromechanical wave imaging (EWI) is an ultrasound-based technique that can non-invasively map the transmural electromechanical activation in all four cardiac chambers in vivo. The objective of this study was to determine the reproducibility and angle independence of EWI for the assessment of electromechanical activation during normal sinus rhythm (NSR) in healthy humans. Acquisitions were performed transthoracically at 2000 frames/s on seven healthy human hearts in parasternal long-axis, apical four- and two-chamber views. EWI data was collected twice successively in each view in all subjects, while four successive acquisitions were obtained in one case. Activation maps were generated and compared (i) within the same acquisition across consecutive cardiac cycles; (ii) within same view across successive acquisitions; and (iii) within equivalent left-ventricular regions across different views. EWI was capable of characterizing electromechanical activation during NSR and of reliably obtaining similar patterns of activation. For consecutive heart cycles, the average 2-D correlation coefficient between the two isochrones across the seven subjects was 0.9893, with a mean average activation time fluctuation in LV wall segments across acquisitions of 6.19%. A mean activation time variability of 12% was obtained across different views with a measurement bias of only 3.2 ms. These findings indicate that EWI can map the electromechanical activation during NSR in human hearts in transthoracic echocardiography in vivo and results in reproducible and angle-independent activation maps. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Large-Scale Noniridescent Structural Color Printing Enabled by Infiltration-Driven Nonequilibrium Colloidal Assembly.

PubMed

Bai, Ling; Mai, Van Cuong; Lim, Yun; Hou, Shuai; Möhwald, Helmuth; Duan, Hongwei

2018-03-01

Structural colors originating from interaction of light with intricately arranged micro-/nanostructures have stimulated considerable interest because of their inherent photostability and energy efficiency. In particular, noniridescent structural color with wide viewing angle has been receiving increasing attention recently. However, no method is yet available for rapid and large-scale fabrication of full-spectrum structural color patterns with wide viewing angles. Here, infiltration-driven nonequilibrium assembly of colloidal particles on liquid-permeable and particle-excluding substrates is demonstrated to direct the particles to form amorphous colloidal arrays (ACAs) within milliseconds. The infiltration-assisted (IFAST) colloidal assembly opens new possibilities for rapid manufacture of noniridescent structural colors of ACAs and straightforward structural color mixing. Full-spectrum noniridescent structural colors are successfully produced by mixing primary structural colors of red, blue, and yellow using a commercial office inkjet printer. Rapid fabrication of large-scale structural color patterns with sophisticated color combination/layout by IFAST printing is realized. The IFAST technology is versatile for developing structural color patterns with wide viewing angles, as colloidal particles, inks, and substrates are flexibly designable for diverse applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A cylindrical specimen holder for electron cryo-tomography.

PubMed

Palmer, Colin M; Löwe, Jan

2014-02-01

The use of slab-like flat specimens for electron cryo-tomography restricts the range of viewing angles that can be used. This leads to the "missing wedge" problem, which causes artefacts and anisotropic resolution in reconstructed tomograms. Cylindrical specimens provide a way to eliminate the problem, since they allow imaging from a full range of viewing angles around the tilt axis. Such specimens have been used before for tomography of radiation-insensitive samples at room temperature, but never for frozen-hydrated specimens. Here, we demonstrate the use of thin-walled carbon tubes as specimen holders, allowing the preparation of cylindrical frozen-hydrated samples of ribosomes, liposomes and whole bacterial cells. Images acquired from these cylinders have equal quality at all viewing angles, and the accessible tilt range is restricted only by the physical limits of the microscope. Tomographic reconstructions of these specimens demonstrate that the effects of the missing wedge are substantially reduced, and could be completely eliminated if a full tilt range was used. The overall quality of these tomograms is still lower than that obtained by existing methods, but improvements are likely in future. © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Using Relative Position and Temporal Judgments to Assess the Effects of Texture and Field of View on Spatial Awareness for Synthetic Vision Systems Displays

NASA Technical Reports Server (NTRS)

Bolton, Matthew L.; Bass, Ellen J.; Comstock, James R., Jr.

2006-01-01

Synthetic Vision Systems (SVS) depict computer generated views of terrain surrounding an aircraft. In the assessment of textures and field of view (FOV) for SVS, no studies have directly measured the 3 levels of spatial awareness: identification of terrain, its relative spatial location, and its relative temporal location. This work introduced spatial awareness measures and used them to evaluate texture and FOV in SVS displays. Eighteen pilots made 4 judgments (relative angle, distance, height, and abeam time) regarding the location of terrain points displayed in 112 5-second, non-interactive simulations of a SVS heads down display. Texture produced significant main effects and trends for the magnitude of error in the relative distance, angle, and abeam time judgments. FOV was significant for the directional magnitude of error in the relative distance, angle, and height judgments. Pilots also provided subjective terrain awareness ratings that were compared with the judgment based measures. The study found that elevation fishnet, photo fishnet, and photo elevation fishnet textures best supported spatial awareness for both the judgments and the subjective awareness measures.

Nicaraguan Volcanoes, 26 February 2000

NASA Image and Video Library

2000-04-19

The true-color image at left is a downward-looking (nadir) view of the area around the San Cristobal volcano, which erupted the previous day. This image is oriented with east at the top and north at the left. The right image is a stereo anaglyph of the same area, created from red band multi-angle data taken by the 45.6-degree aftward and 70.5-degree aftward cameras on the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. View this image through red/blue 3D glasses, with the red filter over the left eye. A plume from San Cristobal (approximately at image center) is much easier to see in the anaglyph, due to 3 effects: the long viewing path through the atmosphere at the oblique angles, the reduced reflection from the underlying water, and the 3D stereoscopic height separation. In this image, the plume floats between the surface and the overlying cumulus clouds. A second plume is also visible in the upper right (southeast of San Cristobal). This very thin plume may originate from the Masaya volcano, which is continually degassing at as low rate. The spatial resolution is 275 meters (300 yards). http://photojournal.jpl.nasa.gov/catalog/PIA02600

Facile Synthesis of Monodispersed Polysulfide Spheres for Building Structural Colors with High Color Visibility and Broad Viewing Angle.

PubMed

Li, Feihu; Tang, Bingtao; Wu, Suli; Zhang, Shufen

2017-01-01

The synthesis and assembly of monodispersed colloidal spheres are currently the subject of extensive investigation to fabricate artificial structural color materials. However, artificial structural colors from general colloidal crystals still suffer from the low color visibility and strong viewing angle dependence which seriously hinder their practical application in paints, colorimetric sensors, and color displays. Herein, monodispersed polysulfide (PSF) spheres with intrinsic high refractive index (as high as 1.858) and light-absorbing characteristics are designed, synthesized through a facile polycondensation and crosslinking process between sodium disulfide and 1,2,3-trichloropropane. Owing to their high monodispersity, sufficient surface charge, and good dispersion stability, the PSF spheres can be assembled into large-scale and high-quality 3D photonic crystals. More importantly, high structural color visibility and broad viewing angle are easily achieved because the unique features of PSF can remarkably enhance the relative reflectivity and eliminate the disturbance of scattering and background light. The results of this study provide a simple and efficient strategy to create structural colors with high color visibility, which is very important for their practical application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Landing of the Shuttle Discovery and end of STS 51-I mission

NASA Technical Reports Server (NTRS)

1985-01-01

Landing of the Shuttle Discovery and end of STS 51-I mission. Views include photo of Discovery's main landing gear just touching down, a cloud of dirt appearing behind it (225); Side view of the main landing gear touching down, the nose gear still above the runway (226); Aft-angle view of the Space Shuttle Discovery as it makes a successful landing (227).

A new illusion of projected three-dimensional space

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.; Grunwald, Arthur

1987-01-01

When perspective projections of orbital trajectories plotted in local-vertical local-horizontal coordinates are viewed with certain viewing angles, their appearance becomes perceptually unstable. They often lose their trochoidal appearance and reorganize as helices. This reorganization may be due to the viewer's familiarity with coiled springs.

Hurricane Alex

Atmospheric Science Data Center

2013-04-19

article title:  Hurricane Alex Disrupts Gulf Cleanup     View Larger Image This view of Hurricane Alex in the western Gulf of Mexico was acquired by the Multi-angle ... Time on June 30, 2010. Around this time NOAA's National Hurricane Center reported Alex to be a strengthening Category 1 hurricane with ...

MISR Global Images See the Light of Day

NASA Technical Reports Server (NTRS)

2002-01-01

As of July 31, 2002, global multi-angle, multi-spectral radiance products are available from the MISR instrument aboard the Terra satellite. Measuring the radiative properties of different types of surfaces, clouds and atmospheric particulates is an important step toward understanding the Earth's climate system. These images are among the first planet-wide summary views to be publicly released from the Multi-angle Imaging SpectroRadiometer experiment. Data for these images were collected during the month of March 2002, and each pixel represents monthly-averaged daylight radiances from an area measuring 1/2 degree in latitude by 1/2 degree in longitude.

The top panel is from MISR's nadir (vertical-viewing) camera and combines data from the red, green and blue spectral bands to create a natural color image. The central view combines near-infrared, red, and green spectral data to create a false-color rendition that enhances highly vegetated terrain. It takes 9 days for MISR to view the entire globe, and only areas within 8 degrees of latitude of the north and south poles are not observed due to the Terra orbit inclination. Because a single pole-to-pole swath of MISR data is just 400 kilometers wide, multiple swaths must be mosaiced to create these global views. Discontinuities appear in some cloud patterns as a consequence of changes in cloud cover from one day to another.

The lower panel is a composite in which red, green, and blue radiances from MISR's 70-degree forward-viewing camera are displayed in the northern hemisphere, and radiances from the 70-degree backward-viewing camera are displayed in the southern hemisphere. At the March equinox (spring in the northern hemisphere, autumn in the southern hemisphere), the Sun is near the equator. Therefore, both oblique angles are observing the Earth in 'forward scattering', particularly at high latitudes. Forward scattering occurs when you (or MISR) observe an object with the Sun at a point in the sky that is in front of you. Relative to the nadir view, this geometry accentuates the appearance of polar clouds, and can even reveal clouds that are invisible in the nadir direction. In relatively clear ocean areas, the oblique-angle composite is generally brighter than its nadir counterpart due to enhanced reflection of light by atmospheric particulates.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Optical Properties of Ice Particles in Young Contrails

NASA Technical Reports Server (NTRS)

Hong, Gang; Feng, Qian; Yang, Ping; Kattawar, George; Minnis, Patrick; Hu, Yong X.

2008-01-01

The single-scattering properties of four types of ice crystals (pure ice crystals, ice crystals with an internal mixture of ice and black carbon, ice crystals coated with black carbon, and soot coated with ice) in young contrails are investigated at wavelengths 0.65 and 2.13 micrometers using Mie codes from coated spheres. The four types of ice crystals have distinct differences in their single-scattering properties because of the embedded black carbon. The bulk scattering properties of young contrails consisting of the four types of ice crystals are further investigated by averaging their single-scattering properties over a typical ice particle size distribution found in young contrails. The effect of the radiative properties of the four types of ice particles on the Stokes parameters I, Q, U, and V is also investigated for different viewing zenith angles and relative azimuth angles with a solar zenith angle of 30 degrees using a vector radiative transfer model based on the adding-doubling technique. The Stokes parameters at a wavelength of 0.65 micrometers show pronounced differences for the four types of ice crystals. Those at a wavelength of 2.13 micrometers show similar variations with the viewing zenith angle and relative azimuth angle, but their values are noticeably different.

Adjustable Bracket For Entry Of Welding Wire

NASA Technical Reports Server (NTRS)

Gilbert, Jeffrey L.; Gutow, David A.

1993-01-01

Wire-entry bracket on welding torch in robotic welding system provides for adjustment of angle of entry of welding wire over range of plus or minus 30 degrees from nominal entry angle. Wire positioned so it does not hide weld joint in view of through-the-torch computer-vision system part of robot-controlling and -monitoring system. Swiveling bracket also used on nonvision torch on which wire-feed-through tube interferes with workpiece. Angle simply changed to one giving sufficient clearance.

Strong Pitch-Angle Diffusion of Ring Current Ions in Geomagnetic Storm-Associated Conditions

NASA Technical Reports Server (NTRS)

Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.; Spann, J. F.

2005-01-01

Do electromagnetic ion cyclotron (EMIC) waves cause strong pitch-angle diffusion of RC ions? This question is the primary motivation of this paper and has been affirmatively answered from the theoretical point of view. The materials that are presented in the Results section show clear evidence that strong pitch-angle diffusion takes place in the inner magnetosphere indicating an important role for the wave-particle interaction mechanism in the formation of RC ions and EMIC waves.

Development of scanning holographic display using MEMS SLM

NASA Astrophysics Data System (ADS)

Takaki, Yasuhiro

2016-10-01

Holography is an ideal three-dimensional (3D) display technique, because it produces 3D images that naturally satisfy human 3D perception including physiological and psychological factors. However, its electronic implementation is quite challenging because ultra-high resolution is required for display devices to provide sufficient screen size and viewing zone. We have developed holographic display techniques to enlarge the screen size and the viewing zone by use of microelectromechanical systems spatial light modulators (MEMS-SLMs). Because MEMS-SLMs can generate hologram patterns at a high frame rate, the time-multiplexing technique is utilized to virtually increase the resolution. Three kinds of scanning systems have been combined with MEMS-SLMs; the screen scanning system, the viewing-zone scanning system, and the 360-degree scanning system. The screen scanning system reduces the hologram size to enlarge the viewing zone and the reduced hologram patterns are scanned on the screen to increase the screen size: the color display system with a screen size of 6.2 in. and a viewing zone angle of 11° was demonstrated. The viewing-zone scanning system increases the screen size and the reduced viewing zone is scanned to enlarge the viewing zone: a screen size of 2.0 in. and a viewing zone angle of 40° were achieved. The two-channel system increased the screen size to 7.4 in. The 360-degree scanning increases the screen size and the reduced viewing zone is scanned circularly: the display system having a flat screen with a diameter of 100 mm was demonstrated, which generates 3D images viewed from any direction around the flat screen.

Assessment of BRDF effect of Kunlun Mountain glacier on Tibetan Plateau as a potential pseudo-invariant calibration site

NASA Astrophysics Data System (ADS)

Wang, Ling; Hu, Xiuqing; Chen, Lin

2017-09-01

Calibration is a critical step to ensure data quality and to meet the requirement of quantitative remote sensing in a broad range of scientific applications. One of the least expensive and increasingly popular methods of on-orbit calibration is the use of pseudo invariant calibration sites (PICS). A spatial homogenous and temporally stable area of 34 km2 in size around the center of Kunlun Mountain (KLM) over Tibetan Plateau (TP) was identified by our previous study. The spatial and temporal coefficient of variation (CV) this region was better than 4% for the reflective solar bands. In this study, the BRDF impacts of KLM glacier on MODIS observed TOA reflectance in band 1 (659 nm) are examined. The BRDF impact of KLM glacier with respect to the view zenith angle is studied through using the observations at a fixed solar zenith angle, and the effect with respect to the sun zenith angle is studied based on the observations collected at the same view angle. Then, the two widely used BRDF models are applied to our test data to simulate the variations of TOA reflectance due to the changes in viewing geometry. The first one is Ross-Li model, which has been used to produce the MODIS global BRDF albedo data product. The second one is snow surface BRDF model, which has been used to characterize the bidirectional reflectance of Antarctic snow. Finally, the accuracy and effectiveness of these two different BRDF models are tested through comparing the model of simulated TOA reflectance with the observed one. The results show that variations of the reflectances at a fixed solar zenith angle are close to the lambertian pattern, while those at a fixed sensor zenith angle are strongly anisotropic. A decrease in solar zenith angle from 50º to 20º causes an increase in reflectance by the level of approximated 50%. The snow surface BRDF model performs much better than the Ross-Li BRDF model to re-produce the Bi-Directional Reflectance of KLM glacier. The RMSE of snow surface BRDF model is 3.60%, which is only half of the RMSE when using Ross-Li model.

Application of phase angle for evaluation of the nutrition status of patients with anorexia nervosa.

PubMed

Małecka-Massalska, Teresa; Popiołek, Joanna; Teter, Mariusz; Homa-Mlak, Iwona; Dec, Mariola; Makarewicz, Agata; Karakuła-Juchnowicz, Hanna

2017-12-30

The evaluation of the nutrition status of patients has been the subject of interest of many scientific disciplines. Any deviation from normal values is a serious clinical problem. There are multiple nutrition status evaluation methods used including diet history, scales and questionnaires, physical examination, anthropometric measurements, biochemical measurements, function tests, as well as bioelectric impedance analysis or adipometry. Phase angle, obtained by means of bioelectric impedance analysis, is another parameter that is being more and more frequently applied in nutrition status monitoring. It is proportional to body cell mass. Its direct correlation with the cellular nutrition status has been documented. High phase angle values signify well-being, while low phase angle values indicate poor condition of cells. The purpose of this paper was to review the current state of knowledge about the application of phase angle in evaluation and monitoring of the nutrition status of patients with anorexia nervosa on the basis of available literature. It was proven that the phase angle values in patients with anorexia nervosa are much lower compared to healthy people. Detailed observations showed phase angle value increase in the course of treatment. The relevance of the commonly used body mass index (BMI) has been questioned due to significant degree of generalization in the nutrition status evaluation. Thus, there is a need for new, objective parameters for nutrition status evaluation, which will assist in the treatment and monitoring of patients in a more meaningful and reliable way. The existing independent studies equivocally confirm the usefulness of phase angle in the evaluation of nutrition status of patients with anorexia nervosa and its broader application in clinical practice is only a matter of time. However, these are merely attempts and they have not yet found wider application in clinical practice in the treatment of anorexia nervosa.

Establishment of the Relationship between the Photochemical Reflectance Index and Canopy Light Use Efficiency Using Multi-angle Hyperspectral Observations

NASA Astrophysics Data System (ADS)

Zhang, Qian; Chen, Jing; Zhang, Yongguang; Qiu, Feng; Fan, Weiliang; Ju, Weimin

2017-04-01

The gross primary production (GPP) of terrestrial ecosystems constitutes the largest global land carbon flux and exhibits significant spatial and temporal variations. Due to its wide spatial coverage, remote sensing technology is shown to be useful for improving the estimation of GPP in combination with light use efficiency (LUE) models. Accurate estimation of LUE is essential for calculating GPP using remote sensing data and LUE models at regional and global scales. A promising method used for estimating LUE is the photochemical reflectance index (PRI = (R531－R570)/(R531 + R570), where R531 and R570 are reflectance at wavelengths 531 and 570 nm) through remote sensing. However, it has been documented that there are certain issues with PRI at the canopy scale, which need to be considered systematically. For this purpose, an improved tower-based automatic canopy multi-angle hyperspectral observation system was established at the Qianyanzhou flux station in China since January of 2013. In each 15-minute observation cycle, PRI was observed at four view zenith angles fixed at solar zenith angle and (37°, 47°, 57°) or (42°, 52°, 62°) in the azimuth angle range from 45° to 325° (defined from geodetic north). To improve the ability of directional PRI observation to track canopy LUE, the canopy is treated as two-big leaves, i.e. sunlit and shaded leaves. On the basis of a geometrical optical model, the observed canopy reflectance for each view angle is separated to four components, i.e. sunlit and shaded leaves and sunlit and shaded backgrounds. To determine the fractions of these four components at each view angle, three models based on different theories are tested for simulating the fraction of sunlit leaves. Finally, a ratio of canopy reflectance to leaf reflectance is used to represent the fraction of sunlit leaves, and the fraction of shaded leaves is calculated with the four-scale geometrical optical model. Thus, sunlit and shaded PRI are estimated using the least squares regression with multi-angle observations. In both the half-hourly and daily time steps, the canopy-level two-leaf PRI (PRIt) can effectively enhance (>50% and >35%, respectively) the correlation between PRI and LUE derived from the tower flux measurements over the big-leaf PRI (PRIb) taken as the arithmetic average of the multi-angle measurements in a given time interval. PRIt is very effective in detecting the low-moderate drought stress on LUE at half-hourly time steps, while ineffective in detecting severe atmospheric water and heat stresses, which is probably due to alternative radiative energy sink, i.e. photorespiration. Overall, the two-leaf approach well overcomes some external effects (e.g. sun-target-view geometry) that interfere with PRI signals.

Effect of image scaling on stereoscopic movie experience

NASA Astrophysics Data System (ADS)

Häkkinen, Jukka P.; Hakala, Jussi; Hannuksela, Miska; Oittinen, Pirkko

2011-03-01

Camera separation affects the perceived depth in stereoscopic movies. Through control of the separation and thereby the depth magnitudes, the movie can be kept comfortable but interesting. In addition, the viewing context has a significant effect on the perceived depth, as a larger display and longer viewing distances also contribute to an increase in depth. Thus, if the content is to be viewed in multiple viewing contexts, the depth magnitudes should be carefully planned so that the content always looks acceptable. Alternatively, the content can be modified for each viewing situation. To identify the significance of changes due to the viewing context, we studied the effect of stereoscopic camera base distance on the viewer experience in three different situations: 1) small sized video and a viewing distance of 38 cm, 2) television and a viewing distance of 158 cm, and 3) cinema and a viewing distance of 6-19 meters. We examined three different animations with positive parallax. The results showed that the camera distance had a significant effect on the viewing experience in small display/short viewing distance situations, in which the experience ratings increased until the maximum disparity in the scene was 0.34 - 0.45 degrees of visual angle. After 0.45 degrees, increasing the depth magnitude did not affect the experienced quality ratings. Interestingly, changes in the camera distance did not affect the experience ratings in the case of television or cinema if the depth magnitudes were below one degree of visual angle. When the depth was greater than one degree, the experience ratings began to drop significantly. These results indicate that depth magnitudes have a larger effect on the viewing experience with a small display. When a stereoscopic movie is viewed from a larger display, other experiences might override the effect of depth magnitudes.

Alteration of maxillary and mandibular growth of adult patients with unoperated isolated cleft palate.

PubMed

Yang, Yunqiang; Wu, Yeke; Gu, Yifei; Yang, Qijian; Shi, Bing; Zheng, Qian; Wang, Yan

2013-07-01

The objective of this study was to investigate the effects of cleft palate itself on the growth of maxilla and mandible. Fifty-two adult female patients with unoperated isolated cleft palate and 52 adult female individuals with normal occlusion were included in our study. Computer software was used for lateral cephalometry measurement. Manual measurement was performed for dental cast measurements, and sample t test analysis was applied to analyze the differences between the 2 groups using SPSS 17.0. The sella-nasion-subspinale point angle, subspinale-nasion-supramentale point angle, and maxillary arch length of the cleft group were significantly smaller than those of the control group (P < 0.01). Both maxillary and mandibular posterior dental arch widths of the cleft group were significantly larger compared with the control group (P < 0.01), whereas the sella-nasion-supramentale point angle, mandible arch length, palate height, and palate shelf inclination did not differ between the 2 groups. The measurements did not differ between the submucosal cleft and the overt cleft patients. Cleft palate itself has adverse effects on the maxilla growth with shorter maxillary arch length and wider posterior dental arch width.

Prediction of Airfoil Characteristics With Higher Order Turbulence Models

NASA Technical Reports Server (NTRS)

Gatski, Thomas B.

1996-01-01

This study focuses on the prediction of airfoil characteristics, including lift and drag over a range of Reynolds numbers. Two different turbulence models, which represent two different types of models, are tested. The first is a standard isotropic eddy-viscosity two-equation model, and the second is an explicit algebraic stress model (EASM). The turbulent flow field over a general-aviation airfoil (GA(W)-2) at three Reynolds numbers is studied. At each Reynolds number, predicted lift and drag values at different angles of attack are compared with experimental results, and predicted variations of stall locations with Reynolds number are compared with experimental data. Finally, the size of the separation zone predicted by each model is analyzed, and correlated with the behavior of the lift coefficient near stall. In summary, the EASM model is able to predict the lift and drag coefficients over a wider range of angles of attack than the two-equation model for the three Reynolds numbers studied. However, both models are unable to predict the correct lift and drag behavior near the stall angle, and for the lowest Reynolds number case, the two-equation model did not predict separation on the airfoil near stall.

Cross-coupling between accommodation and convergence is optimized for a broad range of directions and distances of gaze.

PubMed

Nguyen, Dorothy; Vedamurthy, Indu; Schor, Clifton

2008-03-01

Accommodation and convergence systems are cross-coupled so that stimulation of one system produces responses by both systems. Ideally, the cross-coupled responses of accommodation and convergence match their respective stimuli. When expressed in diopters and meter angles, respectively, stimuli for accommodation and convergence are equal in the mid-sagittal plane when viewed with symmetrical convergence, where historically, the gains of the cross coupling (AC/A and CA/C ratios) have been quantified. However, targets at non-zero azimuth angles, when viewed with asymmetric convergence, present unequal stimuli for accommodation and convergence. Are the cross-links between the two systems calibrated to compensate for stimulus mismatches that increase with gaze-azimuth? We measured the response AC/A and stimulus CA/C ratios at zero azimuth, 17.5 and 30 deg of rightward gaze eccentricities with a Badal Optometer and Wheatstone-mirror haploscope. AC/A ratios were measured under open-loop convergence conditions along the iso-accommodation circle (locus of points that stimulate approximately equal amounts of accommodation to the two eyes at all azimuth angles). CA/C ratios were measured under open-loop accommodation conditions along the iso-vergence circle (locus of points that stimulate constant convergence at all azimuth angles). Our results show that the gain of accommodative-convergence (AC/A ratio) decreased and the bias of convergence-accommodation increased at the 30 deg gaze eccentricity. These changes are in directions that compensate for stimulus mismatches caused by spatial-viewing geometry during asymmetric convergence.

Studies on the influence of axial bends on ultrasonic guided waves in hollow cylinders (pipes)

NASA Astrophysics Data System (ADS)

Verma, Bhupesh; Balasubramaniam, Krishnan; Rajagopal, Prabhu

2013-01-01

Ultrasonic guided waves in hollow cylinders (pipes) are today widely applied as rapid screening tools in the inspection of straight pipe segments in oil, power generation and petrochemical processing industries. However, the characteristics of guided wave propagation across features such as bends in the pipe network are complicated, hampering a wider application of the developed techniques. Although a growing number of studies in recent years have considered guided wave propagation across elbows and U-type bends, the topic is still not very well understood for a general bend angle φ, mean bend radius R and pipe thickness b. Here we use 3D Finite Element (FE) simulation to illumine the propagation of fundamental guided pipe modes across bends of several different angles φ. Two different bend radius regimes, R/λ ≈ 1 and 10 (where λ denotes the wavelength of the mode studied) are considered, exemplifying 'sharp' and gradual or 'slow' bends. Different typical pipe thicknesses b within these regimes are also studied. The results confirm the expectation that different bend radius regimes affect the waves differently. Further, while as observed in earlier studies, at moderate bend radii, fundamental modes travel almost unaffected by an elbow (bend angle φ = 90 degrees), we find that as the bend angle is reduced, there is a progressively larger extent of mode-conversion. These trends and results are validated using experiments.

A real-time and closed-loop control algorithm for cascaded multilevel inverter based on artificial neural network.

PubMed

Wang, Libing; Mao, Chengxiong; Wang, Dan; Lu, Jiming; Zhang, Junfeng; Chen, Xun

2014-01-01

In order to control the cascaded H-bridges (CHB) converter with staircase modulation strategy in a real-time manner, a real-time and closed-loop control algorithm based on artificial neural network (ANN) for three-phase CHB converter is proposed in this paper. It costs little computation time and memory. It has two steps. In the first step, hierarchical particle swarm optimizer with time-varying acceleration coefficient (HPSO-TVAC) algorithm is employed to minimize the total harmonic distortion (THD) and generate the optimal switching angles offline. In the second step, part of optimal switching angles are used to train an ANN and the well-designed ANN can generate optimal switching angles in a real-time manner. Compared with previous real-time algorithm, the proposed algorithm is suitable for a wider range of modulation index and results in a smaller THD and a lower calculation time. Furthermore, the well-designed ANN is embedded into a closed-loop control algorithm for CHB converter with variable direct voltage (DC) sources. Simulation results demonstrate that the proposed closed-loop control algorithm is able to quickly stabilize load voltage and minimize the line current's THD (<5%) when subjecting the DC sources disturbance or load disturbance. In real design stage, a switching angle pulse generation scheme is proposed and experiment results verify its correctness.

A history of gonioscopy.

PubMed

Alward, Wallace L M

2011-01-01

The first view of the iridocorneal angle in a living human occurred accidentally in the late 1800s. Lenses were first used to see the angle in 1914, but practical gonioscopy would not come into existence for many years as the slitlamp and lenses that could be used at the slitlamp were developed. This article reviews the history of gonioscopy.

Master Volunteer Life Cycle: A Wide Angle Lens on the Volunteer Experience

ERIC Educational Resources Information Center

Strauss, Andrea Lorek; Rager, Amy

2017-01-01

Extension master volunteer programs, such as master naturalist and master gardener, often focus heavily on volunteer education. The model presented here describes the full life cycle of a master volunteer's experience in the program, putting education in the context of other essential program components. By zooming out to a wide-angle view of the…

The impact of acquisition angle differences on three-dimensional quantitative coronary angiography.

PubMed

Tu, Shengxian; Holm, Niels R; Koning, Gerhard; Maeng, Michael; Reiber, Johan H C

2011-08-01

Three-dimensional (3D) quantitative coronary angiography (QCA) requires two angiographic views to restore vessel dimensions. This study investigated the impact of acquisition angle differences (AADs) of the two angiographic views on the assessed dimensions by 3D QCA. X-ray angiograms of an assembled brass phantom with different types of straight lesions were recorded at multiple angiographic projections. The projections were randomly matched as pairs and 3D QCA was performed in those pairs with AAD larger than 25°. The lesion length and diameter stenosis in three different lesions, a circular concentric severe lesion (A), a circular concentric moderate lesion (B), and a circular eccentric moderate lesion (C), were measured by 3D QCA. The acquisition protocol was repeated for a silicone bifurcation phantom, and the bifurcation angles and bifurcation core volume were measured by 3D QCA. The measurements were compared with the true dimensions if applicable and their correlation with AAD was studied. 50 matched pairs of angiographic views were analyzed for the brass phantom. The average value of AAD was 48.0 ± 14.1°. The percent diameter stenosis was slightly overestimated by 3D QCA for all lesions: A (error 1.2 ± 0.9%, P < 0.001); B (error 0.6 ± 0.5%, P < 0.001); C (error 1.1 ± 0.6%, P < 0.001). The correlation of the measurements with AAD was only significant for lesion A (R(2) = 0.151, P = 0.005). The lesion length was slightly overestimated by 3D QCA for lesion A (error 0.06 ± 0.18 mm, P = 0.026), but well assessed for lesion B (error -0.00 ± 0.16 mm, P = 0.950) and lesion C (error -0.01 ± 0.18 mm, P = 0.585). The correlation of the measurements with AAD was not significant for any lesion. Forty matched pairs of angiographic views were analyzed for the bifurcation phantom. The average value of AAD was 49.1 ± 15.4°. 3D QCA slightly overestimated the proximal angle (error 0.4 ± 1.1°, P = 0.046) and the distal angle (error 1.5 ± 1.3°, P < 0.001). The correlation with AAD was only significant for the distal angle (R(2) = 0.256, P = 0.001). The correlation of bifurcation core volume measurements with AAD was not significant (P = 0.750). Of the two aforementioned measurements with significant correlation with AAD, the errors tended to increase as AAD became larger. 3D QCA can be used to reliably assess vessel dimensions and bifurcation angles. Increasing the AAD of the two angiographic views does not increase accuracy and precision of 3D QCA for circular lesions or bifurcation dimensions. Copyright © 2011 Wiley-Liss, Inc.

Friction stir welding of Zr-based bulk metallic glass

NASA Astrophysics Data System (ADS)

Ji, Y. S.; Fujii, H.; Maeda, M.; Nakata, K.; Kimura, H.; Inoue, A.; Nogi, K.

2009-05-01

A Zr55Cu30Al10Ni5 bulk metallic glass plate was successfully welded below its crystallization temperature by friction stir welding. The flash formation and heat concentration at the shoulder edge was minimized using a wider tool and the angle of the recessed shoulder surface was 3°. To analyze the crystallization of the base material and stir zone, the microstructure and mechanical properties were analyzed using DSC, XRD, TEM, and micro-hardness. As a result, it was found that the amorphous structure and original mechanical properties were maintained in the whole joints.

Double lens device for tunable harmonic generation of laser beams in KBBF/RBBF crystals or other non-linear optic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaminski, Adam

A method and apparatus to generate harmonically related laser wavelengths includes a pair of lenses at opposing faces of a non-linear optical material. The lenses are configured to promote incoming and outgoing beams to be normal to each outer lens surface over a range of acceptance angles of the incoming laser beam. This reduces reflection loss for higher efficiency operation. Additionally, the lenses allow a wider range of wavelengths for lasers for more universal application. Examples of the lenses include plano-cylindrical and plano-spherical form factors.

Distorted asymmetric cubic nanostructure of soluble fullerene crystals in efficient polymer:fullerene solar cells.

PubMed

Kim, Youngkyoo; Nelson, Jenny; Zhang, Tong; Cook, Steffan; Durrant, James R; Kim, Hwajeong; Park, Jiho; Shin, Minjung; Nam, Sungho; Heeney, Martin; McCulloch, Iain; Ha, Chang-Sik; Bradley, Donal D C

2009-09-22

We found that 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)C(61) (PCBM) molecules make a distorted asymmetric body-centered cubic crystal nanostructure in the bulk heterojunction films of reigoregular poly(3-hexylthiophene) and PCBM. The wider angle of distortion in the PCBM nanocrystals was approximately 96 degrees , which can be assigned to the influence of the attached side group to the fullerene ball of PCBM to bestow solubility. Atom concentration analysis showed that after thermal annealing the PCBM nanocrystals do preferentially distribute above the layer of P3HT nanocrystals inside devices.

6. Elevation view of east side of southernmost end of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Elevation view of east side of southernmost end of building. When joined with photo WA-116-A-7, these photos give a virtually complete elevation view of the east side of the 1896 south section of Building 59. Note that the steep angle of view gives the illusion of a flat roof. For a more accurate depiction of the roof slope, see previous photo's including WA-116-5. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

Telepractice: A Wide-Angle View for Persons with Hearing Loss

ERIC Educational Resources Information Center

Cohn, Ellen R.; Cason, Jana

2012-01-01

This paper presents the current status of telepractice as a service delivery model for persons with hearing loss. Telepractice can be broadly viewed as the delivery of preventative, habilitation, or rehabilitation services through telecommunications technology. Telemedicine and telehealth are closely aligned to telepractice, often with overlapping…

INTERIOR VIEW, PASSAGE AND DOOR LETTING ONTO THE SOUTHEAST BED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR VIEW, PASSAGE AND DOOR LETTING ONTO THE SOUTHEAST BED CHAMBER. THE ANGLED PASSAGE RUNS PARALLEL TO WHAT WAS AN EXTERIOR WALL OF THE THREE-SIDED WINDOW BOW PRESENT IN THE HOUSE’S ORIGINAL CA. 1770 STATE - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

Correlation between gonial angle and dynamic tongue collapse in children with snoring/sleep disordered breathing - an exploratory pilot study.

PubMed

Anderson, S; Alsufyani, N; Isaac, A; Gazzaz, M; El-Hakim, H

2018-06-04

Drug induced sleep endoscopy (DISE) is hoped to identify reasons of failure of adenotonsillectomy (AT) in treating pediatric sleep disordered breathing (SDB). Maxillomandibular disproportion has been studied as another association which may explain alternative pathogenesis of SDB. We aimed to explore the relation between the size of the gonial angle and inclination of the epiglottis measured from cone beam CT (CBCT) and tongue base collapse based on DISE in children with SDB. A retrospective chart review was conducted at a tertiary pediatric center. Children (6-17 years old) assessed at a multi-disciplinary Upper Airway Clinic, diagnosed with SDB and maxillo-mandibular disproportion (MMD), and who underwent DISE were eligible. Variables obtained from the electronic medical records of the clinic and prospective database included demographics, comorbidities, surgeries performed, investigations, DISE findings and CBCT findings. The gonial angle of subjects with and without tongue base collapse (TBC) on SNP were compared. In total 29 patients (13 male, 8 female) age 6-17 (median= 9) were eligible for the study from January 2009 - July 2016. We included 11 subjects, and 10 comparators. The mean gonial angle of the TBC group was 139.3°± 7.6°, while that of the comparison group was 129.4°±3.5 (mean difference -9.937, 95% CI of -15.454 to - 4.421, P = 0.001, power of test 0.95). Additionally, the mean inclination of the epiglottis had a mild positive correlation (r=0.32, p<0.05) with the gonial angle, in the whole cohort. This pilot study suggests that TBC may be mediated by a wider gonial angle in children with SDB patients. The posterior tilt of the epiglottis on CBCT may be a surrogate sign of TBC.

WE-DE-BRA-01: SCIENCE COUNCIL JUNIOR INVESTIGATOR COMPETITION WINNER: Acceleration of a Limited-Angle Intrafraction Verification (LIVE) System Using Adaptive Prior Knowledge Based Image Estimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y; Yin, F; Ren, L

Purpose: To develop an adaptive prior knowledge based image estimation method to reduce the scan angle needed in the LIVE system to reconstruct 4D-CBCT for intrafraction verification. Methods: The LIVE system has been previously proposed to reconstructs 4D volumetric images on-the-fly during arc treatment for intrafraction target verification and dose calculation. This system uses limited-angle beam’s eye view (BEV) MV cine images acquired from the treatment beam together with the orthogonally acquired limited-angle kV projections to reconstruct 4D-CBCT images for target verification during treatment. In this study, we developed an adaptive constrained free-form deformation reconstruction technique in LIVE to furthermore » reduce the scanning angle needed to reconstruct the CBCT images. This technique uses free form deformation with energy minimization to deform prior images to estimate 4D-CBCT based on projections acquired in limited angle (orthogonal 6°) during the treatment. Note that the prior images are adaptively updated using the latest CBCT images reconstructed by LIVE during treatment to utilize the continuity of patient motion.The 4D digital extended-cardiac-torso (XCAT) phantom was used to evaluate the efficacy of this technique with LIVE system. A lung patient was simulated with different scenario, including baseline drifts, amplitude change and phase shift. Limited-angle orthogonal kV and beam’s eye view (BEV) MV projections were generated for each scenario. The CBCT reconstructed by these projections were compared with the ground-truth generated in XCAT.Volume-percentage-difference (VPD) and center-of-mass-shift (COMS) were calculated between the reconstructed and the ground-truth tumors to evaluate the reconstruction accuracy. Results: Using orthogonal-view of 6° kV and BEV- MV projections, the VPD/COMS values were 12.7±4.0%/0.7±0.5 mm, 13.0±5.1%/0.8±0.5 mm, and 11.4±5.4%/0.5±0.3 mm for the three scenarios, respectively. Conclusion: The technique enables LIVE to accurately reconstruct 4D-CBCT images using only orthogonal 6° angle, which greatly improves the efficiency and reduces dose of LIVE for intrafraction verification.« less

A beam-splitter-type 3-D endoscope for front view and front-diagonal view images.

PubMed

Kamiuchi, Hiroki; Masamune, Ken; Kuwana, Kenta; Dohi, Takeyoshi; Kim, Keri; Yamashita, Hiromasa; Chiba, Toshio

2013-01-01

In endoscopic surgery, surgeons must manipulate an endoscope inside the body cavity to observe a large field-of-view while estimating the distance between surgical instruments and the affected area by reference to the size or motion of the surgical instruments in 2-D endoscopic images on a monitor. Therefore, there is a risk of the endoscope or surgical instruments physically damaging body tissues. To overcome this problem, we developed a Ø7- mm 3-D endoscope that can switch between providing front and front-diagonal view 3-D images by simply rotating its sleeves. This 3-D endoscope consists of a conventional 3-D endoscope and an outer and inner sleeve with a beam splitter and polarization plates. The beam splitter was used for visualizing both the front and front-diagonal view and was set at 25° to the outer sleeve's distal end in order to eliminate a blind spot common to both views. Polarization plates were used to avoid overlap of the two views. We measured signal-to-noise ratio (SNR), sharpness, chromatic aberration (CA), and viewing angle of this 3-D endoscope and evaluated its feasibility in vivo. Compared to the conventional 3-D endoscope, SNR and sharpness of this 3-D endoscope decreased by 20 and 7 %, respectively. No significant difference was found in CA. The viewing angle for both the front and front-diagonal views was about 50°. In the in vivo experiment, this 3-D endoscope can provide clear 3-D images of both views by simply rotating its inner sleeve. The developed 3-D endoscope can provide the front and front-diagonal view by simply rotating the inner sleeve, therefore the risk of damage to fragile body tissues can be significantly decreased.

Military display performance parameters

NASA Astrophysics Data System (ADS)

Desjardins, Daniel D.; Meyer, Frederick

2012-06-01

The military display market is analyzed in terms of four of its segments: avionics, vetronics, dismounted soldier, and command and control. Requirements are summarized for a number of technology-driving parameters, to include luminance, night vision imaging system compatibility, gray levels, resolution, dimming range, viewing angle, video capability, altitude, temperature, shock and vibration, etc., for direct-view and virtual-view displays in cockpits and crew stations. Technical specifications are discussed for selected programs.

Spinning angle optical calibration apparatus

DOEpatents

Beer, Stephen K.; Pratt, II, Harold R.

1991-01-01

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

Radiative transfer in shrub savanna sites in Niger: Preliminary results from HAPEX-Sahel. Part 3: Optical dynamics and vegetation index sensitivity to biomass and plant cover

NASA Technical Reports Server (NTRS)

vanLeeuwen, W. J. D.; Huete, A. R.; Duncan, J.; Franklin, J.

1994-01-01

A shrub savannah landscape in Niger was optically characterized utilizing blue, green, red and near-infrared wavelengths. Selected vegetation indices were evaluated for their performance and sensitivity to describe the complex Sahelian soil/vegetation canopies. Bidirectional reflectance factors (BRF) of plants and soils were measured at several view angles, and used as input to various vegetation indices. Both soil and vegetation targets had strong anisotropic reflectance properties, rendering all vegetation index (6) responses to be a direct function of sun and view geometry. Soil background influences were shown to alter the response of most vegetation indices. N-space greenness had the smallest dynamic range in VI response, but the n-space brightness index provided additional useful information. The global environmental monitoring index (GEMI) showed a large 6 dynamic range for bare soils, which was undesirable for a vegetation index. The view angle response of the normalized difference vegetation index (NDVI), atmosphere resistant vegetation index (ARVI) and soil atmosphere resistant vegetation index (SARVI) were asymmetric about nadir for multiple view angles, and were, except for the SARVI, altered seriously by soil moisture and/or soil brightness effects. The soil adjusted vegetation index (SAVI) was least affected by surface soil moisture and was symmetric about nadir for grass vegetation covers. Overall the SAVI, SARVI and the n-space vegetation index performed best under all adverse conditions and were recommended to monitor vegetation growth in the sparsely vegetated Sahelian zone.

Determination of Ice Cloud Models Using MODIS and MISR Data

NASA Technical Reports Server (NTRS)

Xie, Yu; Yang, Ping; Kattawar, George W.; Minnis, Patrick; Hu, Yongxiang; Wu, Dong L.

2012-01-01

Representation of ice clouds in radiative transfer simulations is subject to uncertainties associated with the shapes and sizes of ice crystals within cirrus clouds. In this study, we examined several ice cloud models consisting of smooth, roughened, homogeneous and inhomogeneous hexagonal ice crystals with various aspect ratios. The sensitivity of the bulk scattering properties and solar reflectances of cirrus clouds to specific ice cloud models is investigated using the improved geometric optics method (IGOM) and the discrete ordinates radiative transfer (DISORT) model. The ice crystal habit fractions in the ice cloud model may significantly affect the simulations of cloud reflectances. A new algorithm was developed to help determine an appropriate ice cloud model for application to the satellite-based retrieval of ice cloud properties. The ice cloud particle size retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) data, collocated with Multi-angle Imaging Spectroradiometer (MISR) observations, is used to infer the optical thicknesses of ice clouds for nine MISR viewing angles. The relative differences between view-dependent cloud optical thickness and the averaged value over the nine MISR viewing angles can vary from -0.5 to 0.5 and are used to evaluate the ice cloud models. In the case for 2 July 2009, the ice cloud model with mixed ice crystal habits is the best fit to the observations (the root mean square (RMS) error of cloud optical thickness reaches 0.365). This ice cloud model also produces consistent cloud property retrievals for the nine MISR viewing configurations within the measurement uncertainties.

Grooves and Kinks in the Rings

NASA Image and Video Library

2017-06-19

Many of the features seen in Saturn's rings are shaped by the planet's moons. This view from NASA's Cassini spacecraft shows two different effects of moons that cause waves in the A ring and kinks in a faint ringlet. The view captures the outer edge of the 200-mile-wide (320-kilometer-wide) Encke Gap, in the outer portion of Saturn's A ring. This is the same region features the large propeller called Earhart. Also visible here is one of several kinked and clumpy ringlets found within the gap. Kinks and clumps in the Encke ringlet move about, and even appear and disappear, in part due to the gravitational effects of Pan -- which orbits in the gap and whose gravitational influence holds it open. The A ring, which takes up most of the image on the left side, displays wave features caused by Pan, as well as the moons Pandora and Prometheus, which orbit a bit farther from Saturn on both sides of the planet's F ring. This view was taken in visible light with the Cassini spacecraft narrow-angle camera on March 22, 2017, and looks toward the sunlit side of the rings from about 22 degrees above the ring plane. The view was acquired at a distance of approximately 63,000 miles (101,000 kilometers) from Saturn and at a phase angle (the angle between the sun, the rings and the spacecraft) of 59 degrees. Image scale is 1,979 feet (603 meters) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21333

Development of wide-angle 2D light scattering static cytometry

NASA Astrophysics Data System (ADS)

Xie, Linyan; Liu, Qiao; Shao, Changshun; Su, Xuantao

2016-10-01

We have recently developed a 2D light scattering static cytometer for cellular analysis in a label-free manner, which measures side scatter (SSC) light in the polar angular range from 79 to 101 degrees. Compared with conventional flow cytometry, our cytometric technique requires no fluorescent labeling of the cells, and static cytometry measurements can be performed without flow control. In this paper we present an improved label-free static cytometer that can obtain 2D light scattering patterns in a wider angular range. By illuminating the static microspheres on chip with a scanning optical fiber, wide-angle 2D light scattering patterns of single standard microspheres with a mean diameter of 3.87 μm are obtained. The 2D patterns of 3.87 μm microspheres contain both large-angle forward scatter (FSC) and SSC light in the polar angular range from 40 to 100 degrees, approximately. Experimental 2D patterns of 3.87 μm microspheres are in good agreement with Mie theory simulated ones. The wide-angle light scattering measurements may provide a better resolution for particle analysis as compared with the SSC measurements. Two dimensional light scattering patterns of HL-60 human acute leukemia cells are obtained by using our static cytometer. Compared with SSC 2D light scattering patterns, wide-angle 2D patterns contain richer information of the HL-60 cells. The obtaining of 2D light scattering patterns in a wide angular range could help to enhance the capabilities of our label-free static cytometry for cell analysis.

A contact angle hysteresis model based on the fractal structure of contact line.

PubMed

Wu, Shuai; Ma, Ming

2017-11-01

Contact angle is one of the most popular concept used in fields such as wetting, transport and microfludics. In practice, different contact angles such as equilibrium, receding and advancing contact angles are observed due to hysteresis. The connection among these contact angles is important in revealing the chemical and physical properties of surfaces related to wetting. Inspired by the fractal structure of contact line, we propose a single parameter model depicting the connection of the three angles. This parameter is decided by the fractal structure of the contact line. The results of this model agree with experimental observations. In certain cases, it can be reduced to other existing models. It also provides a new point of view in understanding the physical nature of the contact angle hysteresis. Interestingly, some counter-intuitive phenomena, such as the binary receding angles, are indicated in this model, which are waited to be validated by experiments. Copyright © 2017 Elsevier Inc. All rights reserved.

Upper wide-angle viewing system for ITER.

PubMed

Lasnier, C J; McLean, A G; Gattuso, A; O'Neill, R; Smiley, M; Vasquez, J; Feder, R; Smith, M; Stratton, B; Johnson, D; Verlaan, A L; Heijmans, J A C

2016-11-01

The Upper Wide Angle Viewing System (UWAVS) will be installed on five upper ports of ITER. This paper shows major requirements, gives an overview of the preliminary design with reasons for some design choices, examines self-emitted IR light from UWAVS optics and its effect on accuracy, and shows calculations of signal-to-noise ratios for the two-color temperature output as a function of integration time and divertor temperature. Accurate temperature output requires correction for vacuum window absorption vs. wavelength and for self-emitted IR, which requires good measurement of the temperature of the optical components. The anticipated signal-to-noise ratio using presently available IR cameras is adequate for the required 500 Hz frame rate.

Three-dimensional liquid flattened Luneburg lens with ultra-wide viewing angle and frequency band

NASA Astrophysics Data System (ADS)

Wu, Lingling; Tian, Xiaoyong; Yin, Ming; Li, Dichen; Tang, Yiping

2013-08-01

Traditional Luneburg lens is a dielectric spherical antenna. It can focus the incoming collimated electromagnetic waves on its spherical surface, which causes the incompatibility with the planar feeding and receiving devices. Furthermore, the difficulties in the fabrication process also limited its applications. In this paper, a three-dimensional flattened Luneburg lens with a field-of-view angle up to 180° has been realized based on a liquid medium approach and a 3D-printing process. The fabricated three-dimensional lens showed a broadband transmission characteristic from 12.4 GHz to 18 GHz. The performance of the proposed lens was demonstrated by simulation and experimental results.

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly.

PubMed

Siddique, Radwanul Hasan; Gomard, Guillaume; Hölscher, Hendrik

2015-04-22

The glasswing butterfly (Greta oto) has, as its name suggests, transparent wings with remarkable low haze and reflectance over the whole visible spectral range even for large view angles of 80°. This omnidirectional anti-reflection behaviour is caused by small nanopillars covering the transparent regions of its wings. In difference to other anti-reflection coatings found in nature, these pillars are irregularly arranged and feature a random height and width distribution. Here we simulate the optical properties with the effective medium theory and transfer matrix method and show that the random height distribution of pillars significantly reduces the reflection not only for normal incidence but also for high view angles.

Accommodation measurements of horizontally scanning holographic display.

PubMed

Takaki, Yasuhiro; Yokouchi, Masahito

2012-02-13

Eye accommodation is considered to function properly for three-dimensional (3D) images generated by holography. We developed a horizontally scanning holographic display technique that enlarges both the screen size and viewing zone angle. A 3D image generated by this technique can be easily seen by both eyes. In this study, we measured the accommodation responses to a 3D image generated by the horizontally scanning holographic display technique that has a horizontal viewing zone angle of 14.6° and screen size of 4.3 in. We found that the accommodation responses to a 3D image displayed within 400 mm from the display screen were similar to those of a real object.

The holographic display of three-dimensional medical objects through the usage of a shiftable cylindrical lens

NASA Astrophysics Data System (ADS)

Teng, Dongdong; Liu, Lilin; Zhang, Yueli; Pang, Zhiyong; Wang, Biao

2014-09-01

Through the creative usage of a shiftable cylindrical lens, a wide-view-angle holographic display system is developed for medical object display in real three-dimensional (3D) space based on a time-multiplexing method. The two-dimensional (2D) source images for all computer generated holograms (CGHs) needed by the display system are only one group of computerized tomography (CT) or magnetic resonance imaging (MRI) slices from the scanning device. Complicated 3D message reconstruction on the computer is not necessary. A pelvis is taken as the target medical object to demonstrate this method and the obtained horizontal viewing angle reaches 28°.

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

NASA Astrophysics Data System (ADS)

Siddique, Radwanul Hasan; Gomard, Guillaume; Hölscher, Hendrik

2015-04-01

The glasswing butterfly (Greta oto) has, as its name suggests, transparent wings with remarkable low haze and reflectance over the whole visible spectral range even for large view angles of 80°. This omnidirectional anti-reflection behaviour is caused by small nanopillars covering the transparent regions of its wings. In difference to other anti-reflection coatings found in nature, these pillars are irregularly arranged and feature a random height and width distribution. Here we simulate the optical properties with the effective medium theory and transfer matrix method and show that the random height distribution of pillars significantly reduces the reflection not only for normal incidence but also for high view angles.

Does hemipelvis structure and position influence acetabulum orientation?

PubMed

Musielak, Bartosz; Jóźwiak, Marek; Rychlik, Michał; Chen, Brian Po-Jung; Idzior, Maciej; Grzegorzewski, Andrzej

2016-03-16

Although acetabulum orientation is well established anatomically and radiographically, its relation to the innominate bone has rarely been addressed. If explored, it could open the discussion on patomechanisms of such complex disorders as femoroacetabular impingement (FAI). We therefore evaluated the influence of pelvic bone position and structure on acetabular spatial orientation. We describe this relation and its clinical implications. This retrospective study was based on computed tomography scanning of three-dimensional models of 31 consecutive male pelvises (62 acetabulums). All measurements were based on CT spatial reconstruction with the use of highly specialized software (Rhinoceros). Relations between acetabular orientation (inclination, tilt, anteversion angles) and pelvic structure were evaluated. The following parameters were evaluated to assess the pelvic structure: iliac opening angle, iliac tilt angle, interspinous distance (ISD), intertuberous distance (ITD), height of the pelvis (HP), and the ISD/ITD/HP ratio. The linear and nonlinear dependence of the acetabular angles and hemipelvic measurements were examined with Pearson's product - moment correlation and Spearman's rank correlation coefficient. Correlations different from 0 with p < 0.05 were considered statistically significant. Comparison of the axis position with pelvis structure with orientation in the horizontal plane revealed a significant positive correlation between the acetabular anteversion angle and the iliac opening angle (p = 0.041 and 0.008, respectively). In the frontal plane, there was a positive correlation between the acetabular inclination angle and the iliac tilt angle (p = 0.025 and 0.014, respectively) and the acetabular inclination angle and the ISD/ITD/HP ratio (both p = 0.048). There is a significant correlation of the hemipelvic structure and acetabular orientation under anatomic conditions, especially in the frontal and horizontal planes. In the anteroposterior view, the more tilted-down innominate bone causes a more caudally oriented acetabulum axis, whereas in the horizontal view this relation is reversed. This study may serve as a basis for the discussion on the role of the pelvis in common disorders of the hip.

MISR Scans the Texas-Oklahoma Border

NASA Technical Reports Server (NTRS)

2000-01-01

These MISR images of Oklahoma and north Texas were acquired on March 12, 2000 during Terra orbit 1243. The three images on the left, from top to bottom, are from the 70-degree forward viewing camera, the vertical-viewing (nadir) camera, and the 70-degree aftward viewing camera. The higher brightness, bluer tinge, and reduced contrast of the oblique views result primarily from scattering of sunlight in the Earth's atmosphere, though some color and brightness variations are also due to differences in surface reflection at the different angles. The longer slant path through the atmosphere at the oblique angles also accentuates the appearance of thin, high-altitude cirrus clouds.

On the right, two areas from the nadir camera image are shown in more detail, along with notations highlighting major geographic features. The south bank of the Red River marks the boundary between Texas and Oklahoma. Traversing brush-covered and grassy plains, rolling hills, and prairies, the Red River and the Canadian River are important resources for farming, ranching, public drinking water, hydroelectric power, and recreation. Both originate in New Mexico and flow eastward, their waters eventually discharging into the Mississippi River.

A smoke plume to the north of the Ouachita Mountains and east of Lake Eufaula is visible in the detailed nadir imagery. The plume is also very obvious at the 70-degree forward view angle, to the right of center and about one-fourth of the way down from the top of the image.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Response Versus Scan-Angle Corrections for MODIS Reflective Solar Bands Using Deep Convective Clouds

NASA Technical Reports Server (NTRS)

Bhatt, Rajendra; Angal, Amit; Doelling, David R.; Xiong, Xiaoxiong; Wu, Aisheng; Haney, Conor O.; Scarino, Benjamin R.; Gopalan, Arun

2016-01-01

The absolute radiometric calibration of the reflective solar bands (RSBs) of Aqua- and Terra-MODIS is performed using on-board calibrators. A solar diffuser (SD) panel along with a solar diffuser stability monitor (SDSM) system, which tracks the performance of the SD over time, provides the absolute reference for calibrating the MODIS sensors. MODIS also views the moon and deep space through its space view (SV) port for lunar-based calibration and computing the zero input radiance, respectively. The MODIS instrument views the Earths surface through a two-sided scan mirror, whose reflectance is a function of angle of incidence (AOI) and is described by response versus scan-angle (RVS). The RVS for both MODIS instruments was characterized prior to launch. MODIS also views the SD and the moon at two different assigned RVS positions. There is sufficient evidence that the RVS is changing on orbit over time and as a function of wavelength. The SD and lunar observation scans can only track the RVS variation at two RVS positions. Consequently, the MODIS Characterization Support Team (MCST) developed enhanced approaches that supplement the onboard calibrator measurements with responses from pseudo-invariant desert sites. This approach has been implemented in Level 1B (L1B) Collection 6 (C6) for selected short-wavelength bands. This paper presents an alternative approach of characterizing the mirror RVS to derive the time-dependent RVS correction factors for MODIS RSBs using tropical deep convective cloud (DCC) targets. An initial assessment of the DCC response from Aqua-MODIS band 1 C6 data indicates evidence of RVS artifacts, which are not uniform across the scans and are more prevalent in the left side Earth-view scans.

Response Versus Scan-Angle Corrections for MODIS Reflective Solar Bands Using Deep Convective Clouds

NASA Technical Reports Server (NTRS)

Bhatt, Rajendra; Angal, Amit; Doelling, David R.; Xiong, Xiaoxiong; Wu, Aisheng; Haney, Conor O.; Scarino, Benjamin R.; Gopalan, Arun

2016-01-01

The absolute radiometric calibration of the reflective solar bands (RSBs) of Aqua- and Terra-MODIS is performed using on-board calibrators. A solar diffuser (SD) panel along with a solar diffuser stability monitor (SDSM) system, which tracks the performance of the SD over time, provides the absolute reference for calibrating the MODIS sensors. MODIS also views the moon and deep space through its space view (SV) port for lunar-based calibration and computing the zero input radiance, respectively. The MODIS instrument views the Earth's surface through a two-sided scan mirror, whose reflectance is a function of angle of incidence (AOI) and is described by response versus scan-angle (RVS). The RVS for both MODIS instruments was characterized prior to launch. MODIS also views the SD and the moon at two different assigned RVS positions. There is sufficient evidence that the RVS is changing on orbit over time and as a function of wavelength. The SD and lunar observation scans can only track the RVS variation at two RVS positions. Consequently, the MODIS Characterization Support Team (MCST) developed enhanced approaches that supplement the onboard calibrator measurements with responses from pseudo-invariant desert sites. This approach has been implemented in Level 1B (L1B) Collection 6 (C6) for selected short-wavelength bands. This paper presents an alternative approach of characterizing the mirror RVS to derive the time-dependent RVS correction factors for MODIS RSBs using tropical deep convective cloud (DCC) targets. An initial assessment of the DCC response from Aqua-MODIS band 1 C6 data indicates evidence of RVS artifacts, which are not uniform across the scans and are more prevalent in the left side Earth-view scans.

Response versus scan-angle corrections for MODIS reflective solar bands using deep convective clouds

NASA Astrophysics Data System (ADS)

Bhatt, Rajendra; Angal, Amit; Doelling, David R.; Xiong, Xiaoxiong; Wu, Aisheng; Haney, Conor O.; Scarino, Benjamin R.; Gopalan, Arun

2016-05-01

The absolute radiometric calibration of the reflective solar bands (RSBs) of Aqua- and Terra-MODIS is performed using on-board calibrators. A solar diffuser (SD) panel along with a solar diffuser stability monitor (SDSM) system, which tracks the degradation of the SD over time, provides the baseline for calibrating the MODIS sensors. MODIS also views the moon and deep space through its space view (SV) port for lunar-based calibration and computing the background, respectively. The MODIS instrument views the Earth's surface using a two-sided scan mirror, whose reflectance is a function of the angle of incidence (AOI) and is described by response versus scan-angle (RVS). The RVS for both MODIS instruments was characterized prior to launch. MODIS also views the SD and the moon at two different AOIs. There is sufficient evidence that the RVS is changing on orbit over time and as a function of wavelength. The SD and lunar observation scans can only track the RVS variation at two AOIs. Consequently, the MODIS Characterization Support Team (MCST) developed enhanced approaches that supplement the onboard calibrator measurements with responses from the pseudo-invariant desert sites. This approach has been implemented in Level 1B (L1B) Collection 6 (C6) for select short-wavelength bands. This paper presents an alternative approach of characterizing the mirror RVS to derive the time-dependent RVS correction factors for MODIS RSBs using tropical deep convective cloud (DCC) targets. An initial assessment of the DCC response from Aqua-MODIS band 1 C6 data indicates evidence of RVS artifacts, which are not uniform across the scans and are more prevalent at the beginning of the earth-view scan.

Streaming video-based 3D reconstruction method compatible with existing monoscopic and stereoscopic endoscopy systems

NASA Astrophysics Data System (ADS)

Bouma, Henri; van der Mark, Wannes; Eendebak, Pieter T.; Landsmeer, Sander H.; van Eekeren, Adam W. M.; ter Haar, Frank B.; Wieringa, F. Pieter; van Basten, Jean-Paul

2012-06-01

Compared to open surgery, minimal invasive surgery offers reduced trauma and faster recovery. However, lack of direct view limits space perception. Stereo-endoscopy improves depth perception, but is still restricted to the direct endoscopic field-of-view. We describe a novel technology that reconstructs 3D-panoramas from endoscopic video streams providing a much wider cumulative overview. The method is compatible with any endoscope. We demonstrate that it is possible to generate photorealistic 3D-environments from mono- and stereoscopic endoscopy. The resulting 3D-reconstructions can be directly applied in simulators and e-learning. Extended to real-time processing, the method looks promising for telesurgery or other remote vision-guided tasks.

Classical person-centered and experiential perspectives on Rogers (1957).

PubMed

Elliott, Robert; Friere, Elizabeth

2007-09-01

Rogers (1957; see record 2007-14639-002) foreshadows the later development of the person-centered approach in North America and elsewhere. In this paper, the authors present contrasting perspectives on the legacy of this key paper. First, from the perspective of classical person-centered therapy, Freire describes the context for this key paper within the wider frame of Rogers' body of work and emphasizes its continuing importance and relevance. Second, Elliott offers a personal history from the point of view of a psychotherapy researcher and process-experiential therapist. These two perspectives represent two major and distinct views of Rogers' legacy from within his direct intellectual and therapeutic descendents. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

40 CFR 52.128 - Rule for unpaved parking lots, unpaved roads and vacant lots.

Code of Federal Regulations, 2011 CFR

2011-07-01

... where the exemption in paragraph (c)(2) of this section applies. (9) Motor vehicle—A self-propelled.... Research Triangle Park, N.C. May 1982. 3. “Method 9—Visible Determination of the Opacity of Emissions from... of the human eye—Reference 4.1 of section 4.) c. Angle of view 15 degrees maximum total angle d...

40 CFR 52.128 - Rule for unpaved parking lots, unpaved roads and vacant lots.

Code of Federal Regulations, 2010 CFR

2010-07-01

... where the exemption in paragraph (c)(2) of this section applies. (9) Motor vehicle—A self-propelled.... Research Triangle Park, N.C. May 1982. 3. “Method 9—Visible Determination of the Opacity of Emissions from... of the human eye—Reference 4.1 of section 4.) c. Angle of view 15 degrees maximum total angle d...

Enhancement of Dual-Band Reflection-Mode Circular Polarizers Using Dual-Layer Rectangular Frequency Selective Surfaces

NASA Astrophysics Data System (ADS)

Fartookzadeh, M.; Mohseni Armaki, S. H.

2016-10-01

A new kind of dual-band reflection-mode circular polarizers (RMCPs) is introduced with wide bandwidth and wide-view at the operating frequencies. The proposed RMCPs are based on dual-layer rectangular patches on both sides of a substrate, separated by a foam or air layer from the ground plane. Required TE susceptance of the first layer patches to produce circular polarization is calculated using the equivalent transmission line model. Dimensions of the RMCP are obtained using parametrical study for the two frequency bands, 1.9-2.3 GHz and 7.9-8.3 GHz. In addition, it is indicated that the accepted view angle and bandwidth of the proposed dual-layer RMCP are improved compared with the single layer RMCP, significantly. Moreover, a tradeoff is observed for the dual-layer RMCP on the bandwidths of X band and S band that can be controlled by propagation angle of the incident wave. The proposed RMCP has 30.5 % and 33.7 % bandwidths for less than 3 dB axial ratio with incident angles {\\theta}max=50{\\deg} and {\\theta}min=35{\\deg}. Finally, simulation results are met by the measurement for three angles of the incident wave.

OPTIMUM PHYSICAL VIEWING CONDITIONS FOR A REAR PROJECTION DAYLIGHT SCREEN.

ERIC Educational Resources Information Center

ASH, PHILIP; JASPEN, NATHAN

AN EXPERIMENT DESIGNED TO DISCOVER WHETHER THERE WERE DIFFERENCES IN LEARNING WHICH COULD BE ATTRIBUTED TO DIFFERENCES IN ROOM ILLUMINATION, VIEWING ANGLE, AND DISTANCE FROM THE SCREEN AS THEY RELATED TO THE CABINET-TYPE PROJECTOR WAS PRESENTED. PARTICIPANTS WERE 721 TRAINEES AT THE GREAT LAKES NAVAL TRAINING STATION. THE TASK CHOSEN WAS THE…

Exterior view of the Cupola

NASA Image and Video Library

2011-07-12

ISS028-E-016246 (12 July 2011) --- This is a high angle view showing the Cupola, backdropped against a solar array panel, on the International Space Station. In some of the images in this series, faces of several of the Atlantis STS-135 and Expedition 28 crew members can be seen in the Cupola's windows.

Waving Goodbye

NASA Image and Video Library

2017-05-30

Before NASA's Cassini entered its Grand Finale orbits, it acquired unprecedented views of the outer edges of the main ring system. For example, this close-up view of the Keeler Gap, which is near the outer edge of Saturn's main rings, shows in great detail just how much the moon Daphnis affects the edges of the gap. Daphnis creates waves in the edges of the gap through its gravitational influence. Some clumping of ring particles can be seen in the perturbed edge, similar to what was seen on the edges of the Encke Gap back when Cassini arrived at Saturn in 2004. This view looks toward the sunlit side of the rings from about 3 degrees above the ring plane. The view was acquired at a distance of approximately 18,000 miles (30,000 kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 69 degrees. Image scale is 581 feet (177 meters) per pixel. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 16, 2017. https://photojournal.jpl.nasa.gov/catalog/PIA21329

The Impacts of Bowtie Effect and View Angle Discontinuity on MODIS Swath Data Gridding

NASA Technical Reports Server (NTRS)

Wang, Yujie; Lyapustin, Alexei

2007-01-01

We have analyzed two effects of the MODIS viewing geometry on the quality of gridded imagery. First, the fact that the MODIS scans a swath of the Earth 10 km wide at nadir, causes abrupt change of the view azimuth angle at the boundary of adjacent scans. This discontinuity appears as striping of the image clearly visible in certain cases with viewing geometry close to principle plane over the snow of the glint area of water. The striping is a true surface Bi-directional Reflectance Factor (BRF) effect and should be preserved during gridding. Second, due to bowtie effect, the observations in adjacent scans overlap each other. Commonly used method of calculating grid cell value by averaging all overlapping observations may result in smearing of the image. This paper describes a refined gridding algorithm that takes the above two effects into account. By calculating the grid cell value by averaging the overlapping observations from a single scan, the new algorithm preserves the measured BRF signal and enhances sharpness of the image.

Matched-pair analyses of resting and dynamic morphology between Monarc and TVT-O procedures by ultrasound.

PubMed

Yang, Jenn-Ming; Yang, Shwu-Huey; Huang, Wen-Chen; Tzeng, Chii-Ruey

2013-07-01

To determine morphologic differences between Monarc and TVT-O procedures in axial and coronal planes by three- and four-dimensional (3D and 4D) ultrasound. Retrospective chart audits and ultrasound analyses were conducted on 128 women who had undergone either Monarc or TVT-O procedures for urodynamic stress incontinence. Thirty matched pairs of the two successful procedures were randomly selected and compared. Matched variables were age, parity, body mass index, cesarean status, menopausal status, and primary surgeries. Six-month postoperative 3D and 4D ultrasound results obtained at rest, on straining, and during coughing in these 60 women were analyzed. Assessed ultrasound parameters included the axial tape urethral distance (aTUD), axial central urethral echolucent area (aUCEA), axial tape angle (aTA), and coronal tape angle (cTA), all of which were measured at three equidistant points along the tapes. Paired t-tests were used to compare differences in ultrasound parameters between women after the two procedures and a P value <0.004 was considered significant after Bonferroni correction. At rest, women subjected to Monarc procedures had a significantly wider aTA at one-fourth of the tape and a wider cTA at one-, two-, and three-fourths of the tape than did those subjected to TVT-O procedures. There were no significant differences in other resting ultrasound parameters between these two procedures. Additionally, after both procedures women had comparable straining and coughing ultrasound manifestations as well as respective dynamic changes. Despite flatter resting tape angulations in women following Monarc procedures, both Monarc and TVT-O tapes had equivalent dynamic patterns and changes assessed by 4D ultrasound. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Altered Anterior Segment Biometric Parameters in Mice Deficient in SPARC.

PubMed

Ho, Henrietta; Htoon, Hla M; Yam, Gary Hin-Fai; Toh, Li Zhen; Lwin, Nyein Chan; Chu, Stephanie; Lee, Ying Shi; Wong, Tina T; Seet, Li-Fong

2017-01-01

Secreted protein acidic and rich in cysteine (SPARC) and Hevin are structurally related matricellular proteins involved in extracellular matrix assembly. In this study, we compared the anterior chamber biometric parameters and iris collagen properties in SPARC-, Hevin- and SPARC-/Hevin-null with wild-type (WT) mice. The right eyes of 53 WT, 35 SPARC-, 56 Hevin-, and 63 SPARC-/Hevin-null mice were imaged using the RTVue-100 Fourier-domain optical coherence tomography system. The parameters measured were anterior chamber depth (ACD), trabecular-iris space area (TISA), angle opening distance (AOD), and pupil diameter. Biometric data were analyzed using analysis of covariance and adjusted for age, sex, and pupil diameter. Expression of Col1a1, Col8a1, and Col8a2 transcripts in the irises was measured by quantitative polymerase chain reaction. Collagen fibril thickness was evaluated by transmission electron microscopy. Mice that were SPARC- and SPARC-/Hevin-null had 1.28- and 1.25-fold deeper ACD, 1.45- and 1.53-fold larger TISA, as well as 1.42- and 1.51-fold wider AOD than WT, respectively. These measurements were not significantly different between SPARC- and SPARC-/Hevin-null mice. The SPARC-null iris expressed lower Col1a1, but higher Col8a1 and Col8a2 transcripts compared with WT. Collagen fibrils in the SPARC- and SPARC-/Hevin-null irises were 1.5- and 1.7-fold thinner than WT, respectively. The Hevin-null iris did not differ from WT in these collagen properties. SPARC-null mice have deeper anterior chamber as well as wider drainage angles compared with WT. Therefore, SPARC plays a key role in influencing the spatial organization of the anterior segment, potentially via modulation of collagen properties, while Hevin is not likely to be involved.