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Sample records for illumination

  1. Demand illumination control apparatus

    NASA Technical Reports Server (NTRS)

    Warren, Carl (Inventor); Arline, Jimmie (Inventor); LaPalme, Julius (Inventor)

    1981-01-01

    Solar illuminating compensating apparatus is disclosed whereby the interior of a building is illuminated to a substantially constant, predetermined level of light intensity by a combination of natural illumination from the sun and artificial illumination from electricity wherein the intensity of said artificial illumination is controlled by fully electronic means which increases the level of artificial illumination when the natural illumination is inadequate and vice versa.

  2. Hotsphere illumination

    NASA Astrophysics Data System (ADS)

    Razavi, Bahar S.; Kuzyakov, Yakov

    2016-04-01

    Soils are the most heterogeneous parts of the biosphere, with an extremely high differentiation of properties and processes at all spatial and temporal scales. Importance of the hotspheres such as rhizosphere, detritusphere, porosphere (including drilosphere and biopores), hyphasphere and spermosphere, calls for spatially explicit methods to illuminate distribution of microbial activities in these hotspheres (Kuzyakov and Blagodatskaya, 2015). Zymography technique has previously been adapted to visualize the spatial dynamics of enzyme activities in rhizosphere (Spohn and Kuzyakov, 2014). Here, we further developed soil zymography to obtain a higher resolution of enzyme activities by enabling direct contact of substrate-saturated membranes with soil. For the first time, we aimed at quantitative imaging of enzyme activities in various hotspheres. We calculated and compared percentage of enzymatic hotspots of five hotspheres: spermosphere, rhizosphere, detritusphere, drilosphere and biopores. Spatial distribution of activities of two enzymes: β-glucosidase and leucine amino peptidase were analyzed in the spermosphere, rhizosphere and detritusphere of maize and lentil. Zymography has been done 3 days (spermosphere), 14 days (rhizosphere) after sowing and 21 days after cutting plant (detritusphere). Spatial resolution of fluorescent images was improved by direct application fluorogenically labelled substrates on the soil surface. Such improvement enabled to visualize enzyme distribution of mycorrhiza hypha on the rhizobox surface. Further, to visualize the 2D distribution of the enzyme activities in porosphere, we placed earthworms (Lumbricus terrestris), (drilosphere) and ground beetle species Platynus dorsalis Pont. (Coleoptera; Carabidae), (biopore), in transparent boxes for 2weeks. The developed in situ zymography visualized the heterogeneity of enzyme activities along and across the roots. Spatial patterns of enzyme activities as a function of distance along the

  3. Lunar South Pole Illumination

    NASA Video Gallery

    Simulated illumination conditions over the lunar South Pole region, from ~80°S to the pole. The movie runs for 28 days, centered on the LCROSS impact date on October 9th, 2009. The illumination ca...

  4. Lights illuminate surfaces superluminally

    NASA Astrophysics Data System (ADS)

    Nemiroff, Robert J.; Zhong, Qi; Lilleskov, Elias

    2016-07-01

    When a light bulb is turned on, light moves away from it at speed c, by definition. When light from this bulb illuminates a surface, however, this illumination front is not constrained to move at speed c. A simple proof is given that this illumination front always moves faster than c. Generalized, when any compact light source itself varies, this information spreads across all of the surfaces it illuminates at speeds faster than light.

  5. Illumination Under Trees

    SciTech Connect

    Max, N

    2002-08-19

    This paper is a survey of the author's work on illumination and shadows under trees, including the effects of sky illumination, sun penumbras, scattering in a misty atmosphere below the trees, and multiple scattering and transmission between leaves. It also describes a hierarchical image-based rendering method for trees.

  6. Grouping Illumination Frameworks

    ERIC Educational Resources Information Center

    Zdravkovic, Suncica; Economou, Elias; Gilchrist, Alan

    2012-01-01

    According to Koffka (1935), the lightness of a target surface is determined by the relationship between the target and the illumination frame of reference to which it belongs. However, each scene contains numerous illumination frames, and judging each one separately would lead to an enormous amount of computing. Grouping those frames that are in…

  7. Shackleton Crater Illumination

    NASA Video Gallery

    Simulated illumination conditions near the lunar South Pole. The 30km x 30km region highlights the Shackleton crater. The movie runs for 28 days, centered on the LCROSS impact date on October 9th, ...

  8. Wood's lamp illumination (image)

    MedlinePlus

    A Wood's lamp emits ultraviolet light and can be a diagnostic aid in determining if someone has a fungal ... is an infection on the area where the Wood's lamp is illuminating, the area will fluoresce. Normally ...

  9. Illuminating black holes

    NASA Astrophysics Data System (ADS)

    Barr, Ian A.; Bull, Anne; O'Brien, Eileen; Drillsma-Milgrom, Katy A.; Milgrom, Lionel R.

    2016-07-01

    Two-dimensional shadows formed by illuminating vortices are shown to be visually analogous to the gravitational action of black holes on light and surrounding matter. They could be useful teaching aids demonstrating some of the consequences of general relativity.

  10. Illumination in diverse codimensions

    NASA Technical Reports Server (NTRS)

    Banks, David C.

    1994-01-01

    This paper derives a model of diffuse and specular illumination in arbitrarily large dimensions, based on a few characteristics of material and light in three-space. It then describes how to adjust for the anomaly of excess brightness in large codimensions. If a surface is grooved or furry, it can be illuminated with a hybrid model that incorporates both the one dimensional geometry (the grooves or fur) and the two dimensional geometry (the surface).

  11. Natural light illumination system.

    PubMed

    Whang, Allen Jong-Woei; Chen, Yi-Yung; Yang, Shu-Hua; Pan, Po-Hsuan; Chou, Kao-Hsu; Lee, Yu-Chi; Lee, Zong-Yi; Chen, Chi-An; Chen, Cheng-Nan

    2010-12-10

    In recent years, green energy has undergone a lot of development and has been the subject of many applications. Many research studies have focused on illumination with sunlight as a means of saving energy and creating healthy lighting. Natural light illumination systems have collecting, transmitting, and lighting elements. Today, most daylight collectors use dynamic concentrators; these include Sun tracking systems. However, this design is too expensive to be cost effective. To create a low-cost collector that can be easily installed on a large building, we have designed a static concentrator, which is prismatic and cascadable, to collect sunlight for indoor illumination. The transmission component uses a large number of optical fibers. Because optical fibers are expensive, this means that most of the cost for the system will be related to transmission. In this paper, we also use a prismatic structure to design an optical coupler for coupling n to 1. With the n-to-1 coupler, the number of optical fibers necessary can be greatly reduced. Although this new natural light illumination system can effectively guide collected sunlight and send it to the basement or to other indoor places for healthy lighting, previously there has been no way to manage the collected sunlight when lighting was not desired. To solve this problem, we have designed an optical switch and a beam splitter to control and separate the transmitted light. When replacing traditional sources, the lighting should have similar characteristics, such as intensity distribution and geometric parameters, to those of traditional artificial sources. We have designed, simulated, and optimized an illumination lightpipe with a dot pattern to redistribute the collected sunlight from the natural light illumination system such that it equals the qualities of a traditional lighting system. We also provide an active lighting module that provides lighting from the natural light illumination system or LED auxiliary

  12. Bright field illumination system

    NASA Technical Reports Server (NTRS)

    Huber, Edward D. (Inventor)

    1998-01-01

    A Bright Field Illumination system for inspecting a range of characteristically different kinds of defects, depressions, and ridges in a selected material surface. The system has an illumination source placed near a first focus of an elliptical reflector. In addition, a camera facing the inspected area is placed near the illumination source and the first focus. The second focus of the elliptical reflector is located at a distance approximately twice the elliptical reflector's distance above the inspected surface. The elliptical reflector directs the light from the source onto the inspected surface. Due to the shape of the elliptical reflector, light that is specularly reflected from the inspected surface is directed into the camera is which located at the position of the reflected second focus of the ellipse. This system creates a brightly lighted background field against which damage sites appear as high contrast dark objects which can be easily detected by a person or an automated inspection system. In addition, the Bright Field Illumination system and method can be used in combination with a vision inspection system providing for multiplexed illumination and data handling of multiple kinds of surface characteristics including abrupt and gradual surface variations and differences between measured characteristics of different kinds and prior instruments.

  13. OLED area illumination source

    DOEpatents

    Foust, Donald Franklin; Duggal, Anil Raj; Shiang, Joseph John; Nealon, William Francis; Bortscheller, Jacob Charles

    2008-03-25

    The present invention relates to an area illumination light source comprising a plurality of individual OLED panels. The individual OLED panels are configured in a physically modular fashion. Each OLED panel comprising a plurality of OLED devices. Each OLED panel comprises a first electrode and a second electrode such that the power being supplied to each individual OLED panel may be varied independently. A power supply unit capable of delivering varying levels of voltage simultaneously to the first and second electrodes of each of the individual OLED panels is also provided. The area illumination light source also comprises a mount within which the OLED panels are arrayed.

  14. Nonimaging optical illumination system

    DOEpatents

    Winston, R.; Ries, H.

    1996-12-17

    A nonimaging illumination optical device for producing a selected far field illuminance over an angular range. The optical device includes a light source, a light reflecting surface, and a family of light edge rays defined along a reference line with the reflecting surface defined in terms of the reference line as a parametric function R(t) where t is a scalar parameter position and R(t)=k(t)+Du(t) where k(t) is a parameterization of the reference line, and D is a distance from a point on the reference line to the reflection surface along the desired edge ray through the point. 35 figs.

  15. Nonimaging optical illumination system

    DOEpatents

    Winston, R.; Ries, H.

    1998-10-06

    A nonimaging illumination optical device for producing a selected far field illuminance over an angular range. The optical device includes a light source a light reflecting surface, and a family of light edge rays defined along a reference line with the reflecting surface defined in terms of the reference lines a parametric function R(t) where t is a scalar parameter position and R(t)=k(t)+Du(t) where k(t) is a parameterization of the reference line, and D is a distance from a point on the reference line to the reflection surface along the desired edge ray through the point. 35 figs.

  16. Nonimaging Optical Illumination System

    DOEpatents

    Winston, Roland

    1994-02-22

    A nonimaging illumination or concentration optical device. An optical device is provided having a light source, a light reflecting surface with an opening and positioned partially around the light source which is opposite the opening of the light reflecting surface. The light reflecting surface is disposed to produce a substantially uniform intensity output with the reflecting surface defined in terms of a radius vector R.sub.i in conjunction with an angle .phi..sub.i between R.sub.i, a direction from the source and an angle .theta..sub.i between direct forward illumination and the light ray reflected once from the reflecting surface. R.sub.i varies as the exponential of tan (.phi..sub.i -.theta..sub.i)/2 integrated over .phi..sub.i.

  17. Nonimaging optical illumination system

    DOEpatents

    Winston, Roland; Ries, Harald

    1996-01-01

    A nonimaging illumination optical device for producing a selected far field illuminance over an angular range. The optical device includes a light source 102, a light reflecting surface 108, and a family of light edge rays defined along a reference line 104 with the reflecting surface 108 defined in terms of the reference line 104 as a parametric function R(t) where t is a scalar parameter position and R(t)=k(t)+Du(t) where k(t) is a parameterization of the reference line 104, and D is a distance from a point on the reference line 104 to the reflection surface 108 along the desired edge ray through the point.

  18. Nonimaging optical illumination system

    DOEpatents

    Winston, Roland; Ries, Harald

    1998-01-01

    A nonimaging illumination optical device for producing a selected far field illuminance over an angular range. The optical device includes a light source 102, a light reflecting surface 108, and a family of light edge rays defined along a reference line 104 with the reflecting surface 108 defined in terms of the reference line 104 as a parametric function R(t) where t is a scalar parameter position and R(t)=k(t)+Du(t) where k(t) is a parameterization of the reference line 104, and D is a distance from a point on the reference line 104 to the reflection surface 108 along the desired edge ray through the point.

  19. Nonimaging optical illumination system

    DOEpatents

    Winston, Roland; Ries, Harald

    2000-01-01

    A nonimaging illumination optical device for producing a selected far field illuminance over an angular range. The optical device includes a light source 102, a light reflecting surface 108, and a family of light edge rays defined along a reference line 104 with the reflecting surface 108 defined in terms of the reference line 104 as a parametric function R(t) where t is a scalar parameter position and R(t)=k(t)+Du(t) where k(t) is a parameterization of the reference line 104, and D is a distance from a point on the reference line 104 to the reflection surface 108 along the desired edge ray through the point.

  20. Nonimaging Optical Illumination System

    DOEpatents

    Winston, Roland

    1994-08-02

    A nonimaging illumination optical device for producing selected intensity output over an angular range. The device includes a light reflecting surface (24, 26) around a light source (22) which is disposed opposite the aperture opening of the light reflecting surface (24, 26). The light source (22) has a characteristic dimension which is small relative to one or more of the distance from the light source (22) to the light reflecting surface (24, 26) or the angle subtended by the light source (22) at the light reflecting surface (24, 26).

  1. Ellipticus CW Illumination System

    DTIC Science & Technology

    2012-08-07

    conceived the idea of making the antenna out of coaxial cable instead of wire and loading the outer conductor with resis- tively damped ferrite ...radiat- ing gap and match the impedance of the antenna as shown in Figure 4. The ferrite bead design, as well as that of the balun, was quite a...Illuminator at Patuxent River NAS. 3.2.1 Wormhole feed concept. The method chosen for driving the radiat- ing gap at the top of the antenna was what Dr

  2. Parallel hierarchical global illumination

    SciTech Connect

    Snell, Quinn O.

    1997-10-08

    Solving the global illumination problem is equivalent to determining the intensity of every wavelength of light in all directions at every point in a given scene. The complexity of the problem has led researchers to use approximation methods for solving the problem on serial computers. Rather than using an approximation method, such as backward ray tracing or radiosity, the authors have chosen to solve the Rendering Equation by direct simulation of light transport from the light sources. This paper presents an algorithm that solves the Rendering Equation to any desired accuracy, and can be run in parallel on distributed memory or shared memory computer systems with excellent scaling properties. It appears superior in both speed and physical correctness to recent published methods involving bidirectional ray tracing or hybrid treatments of diffuse and specular surfaces. Like progressive radiosity methods, it dynamically refines the geometry decomposition where required, but does so without the excessive storage requirements for ray histories. The algorithm, called Photon, produces a scene which converges to the global illumination solution. This amounts to a huge task for a 1997-vintage serial computer, but using the power of a parallel supercomputer significantly reduces the time required to generate a solution. Currently, Photon can be run on most parallel environments from a shared memory multiprocessor to a parallel supercomputer, as well as on clusters of heterogeneous workstations.

  3. Split-illumination electron holography

    SciTech Connect

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

    2012-07-23

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  4. Illuminated push-button switch

    NASA Astrophysics Data System (ADS)

    Iwagiri, T.

    1983-05-01

    An illuminated push-button switch is described. It is characterized by the fact that is consists of a switch group, an operator button opening and closing the switch group, and a light-emitting element which illuminates the face of the operator button.

  5. Optical tomography with structured illumination.

    PubMed

    Lukic, Vladimir; Markel, Vadim A; Schotland, John C

    2009-04-01

    We consider the image reconstruction problem for optical tomography with structured illumination. A fast image reconstruction algorithm is proposed that reduces the required number of measurements of the optical field compared to methods that utilize point-source illumination. The results are illustrated with numerical simulations.

  6. Do humans discount the illuminant?

    NASA Astrophysics Data System (ADS)

    McCann, John J.

    2005-03-01

    In constancy experiments, humans report very small changes in appearance with substantial illumination changes. Hermann von Helmholtz introduced the term "discounting the illuminant" to describe 19th century thinking about underlying mechanisms of constancy. It uses an indirect approach. Since observers see objects as constant, observers "must" be able to detect the spatial and spectral changes in illumination and automatically compensate by altering the signals from the quanta catches of retinal receptors. Instead of solving the problem directly by calculating an object"s reflectance from the array of scene radiances, Helmholtz chose to solve the problem of identifying the illumination. Twentieth century experiments by Hubel and Wiesel, Campbell, Land, and Gibson demonstrate the power of mechanisms using spatial comparisons. This paper analyses a series of different experiments looking for unequivocal evidence that either supports "discounting the illuminant" or supports spatial comparisons as the underlying mechanism of constancy.

  7. Matching illumination of solid objects.

    PubMed

    Pont, Sylvia C; Koenderink, Jan J

    2007-04-01

    The appearance of objects is determined by their surface reflectance and roughness and by the light field. Conversely, human observers might derive properties of the light field from the appearance of objects. The inverse problem has no unique solution, so perceptual interactions between reflectance, roughness, and lightfield are to be expected. In two separate experiments, we tested whether observers are able to match the illumination of spheres under collimated illumination only (matching of illumination direction) and under more or less diffuse illumination (matching of illumination direction and directedness of the beam). We found that observers are quite able to match collimated illumination directions of two rendered Lambertian spheres. Matching of the collimated beam directions of a Lambertian sphere and that of a real object with arbitrary reflectance and roughness properties resulted in similar results for the azimuthal angle, but in higher variance for the polar angle. Translucent objects and a tennis ball were found to be systematic outliers. If the directedness of the beam was also varied, the direction settings showed larger variance for more diffuse illumination. The directedness settings showed an overall quite large variance and, interestingly, interacted with the polar angle settings. We discuss possible photometrical mechanisms behind these effects.

  8. Structured illumination temporal compressive microscopy

    PubMed Central

    Yuan, Xin; Pang, Shuo

    2016-01-01

    We present a compressive video microscope based on structured illumination with incoherent light source. The source-side illumination coding scheme allows the emission photons being collected by the full aperture of the microscope objective, and thus is suitable for the fluorescence readout mode. A 2-step iterative reconstruction algorithm, termed BWISE, has been developed to address the mismatch between the illumination pattern size and the detector pixel size. Image sequences with a temporal compression ratio of 4:1 were demonstrated. PMID:27231586

  9. Hourly Illumination of Shackleton Crater

    NASA Video Gallery

    Illumination of Shackleton crater, a 21-km-diameter (12.5 mile-diameter) structure situated adjacent to the Moon’s south pole. The resolution is 30 meters (approximately 100 feet) per pixel. Fra...

  10. Laser sources for object illumination

    SciTech Connect

    Albrecht, G.F.

    1994-11-15

    The considerations which formulate the specifications for a laser illuminator are explained, using the example of an underwater object. Depending on the parameters which define the scenario, widely varying laser requirements result.

  11. Scanned Laser Illuminator/Receiver

    DTIC Science & Technology

    1976-11-01

    illustrate parallel development of the PIN diode /CCD sensor hybrid and the 100W laser . Al- though a detailed cost analysis for procurement of this large...pmww^^W .m^n.m .,** ■ —ssa^ AFAL-TR-76-184 \\ SCANNED LASER ILLUMINATOR/RECEIVER ^ R. A. Honzik and F. B. Warren ^•Martin Marietta...NUMBER 4. TITLE (and Sublille) SCANNED LASER ILLUMINATOR/RECEIVER 5, TYPE OF REPORT & PERIOD COVERED Final Technical Report Dec 75

  12. Image plane sweep volume illumination.

    PubMed

    Sundén, Erik; Ynnerman, Anders; Ropinski, Timo

    2011-12-01

    In recent years, many volumetric illumination models have been proposed, which have the potential to simulate advanced lighting effects and thus support improved image comprehension. Although volume ray-casting is widely accepted as the volume rendering technique which achieves the highest image quality, so far no volumetric illumination algorithm has been designed to be directly incorporated into the ray-casting process. In this paper we propose image plane sweep volume illumination (IPSVI), which allows the integration of advanced illumination effects into a GPU-based volume ray-caster by exploiting the plane sweep paradigm. Thus, we are able to reduce the problem complexity and achieve interactive frame rates, while supporting scattering as well as shadowing. Since all illumination computations are performed directly within a single rendering pass, IPSVI does not require any preprocessing nor does it need to store intermediate results within an illumination volume. It therefore has a significantly lower memory footprint than other techniques. This makes IPSVI directly applicable to large data sets. Furthermore, the integration into a GPU-based ray-caster allows for high image quality as well as improved rendering performance by exploiting early ray termination. This paper discusses the theory behind IPSVI, describes its implementation, demonstrates its visual results and provides performance measurements.

  13. Specimen illumination apparatus with optical cavity for dark field illumination

    DOEpatents

    Pinkel, Daniel; Sudar, Damir; Albertson, Donna

    1999-01-01

    An illumination apparatus with a specimen slide holder, an illumination source, an optical cavity producing multiple reflection of illumination light to a specimen comprising a first and a second reflective surface arranged to achieve multiple reflections of light to a specimen is provided. The apparatus can further include additional reflective surfaces to achieve the optical cavity, a slide for mounting the specimen, a coverslip which is a reflective component of the optical cavity, one or more prisms for directing light within the optical cavity, antifading solutions for improving the viewing properties of the specimen, an array of materials for analysis, fluorescent components, curved reflective surfaces as components of the optical cavity, specimen detection apparatus, optical detection equipment, computers for analysis of optical images, a plane polarizer, fiberoptics, light transmission apertures, microscopic components, lenses for viewing the specimen, and upper and lower mirrors above and below the specimen slide as components of the optical cavity. Methods of using the apparatus are also provided.

  14. Multiple-illumination photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Barber, Quinn M.; Zemp, Roger J.

    2016-03-01

    Previously we described the potential for multiple illumination photoacoustic tomography to provide quantitative reconstructions, however this work used only simulated data. We have developed a custom photoacoustic-ultrasound tomography system capable of multiple illuminations and parallel acquisition from a 256 element 5 MHz transducer ring array with 8-cm diameter. The multiple illumination scheme uses a free-space light delivery geometry where a rotational stage scans a pulsed laser beam onto different incident locations around the sample. For each illumination location a photoacoustic image is reconstructed using a modified backprojection algorithm. Images from different source locations have the potential to be combined to form an improved deep-tissue image using our previously developed iterative algorithms. We complement the photoacoustic imaging data with unique ultrasound imaging data. Most previous ultrasound tomography methods have used migration algorithms, iterative ray-based analysis, wave-equation modeling, or frequency-based algorithms that all demand large amounts of data and computational power. We propose a new UST method that offers isotropic resolution, provides scattering contrast, as well as the potential for measuring ultrasound scattering anisotropy and decoupling density and compressibility contributions. The imaging system is driven by a Verasonics scan engine and programmed for both ultrasound and photoacoustic imaging modes. Resolution has been measured to be 150 μm for ultrasound and 200 μm for photoacoustic images. Imaging capabilities are demonstrated on phantoms with custom-tailored ultrasound scattering and optical properties, as well as in murine models.

  15. Laser illuminated flat panel display

    SciTech Connect

    Veligdan, J.T.

    1995-12-31

    A 10 inch laser illuminated flat panel Planar Optic Display (POD) screen has been constructed and tested. This POD screen technology is an entirely new concept in display technology. Although the initial display is flat and made of glass, this technology lends itself to applications where a plastic display might be wrapped around the viewer. The display screen is comprised of hundreds of planar optical waveguides where each glass waveguide represents a vertical line of resolution. A black cladding layer, having a lower index of refraction, is placed between each waveguide layer. Since the cladding makes the screen surface black, the contrast is high. The prototype display is 9 inches wide by 5 inches high and approximately I inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

  16. DARK-FIELD ILLUMINATION SYSTEM

    DOEpatents

    Norgren, D.U.

    1962-07-24

    A means was developed for viewing objects against a dark background from a viewing point close to the light which illuminates the objects and under conditions where the back scattering of light by the objects is minimal. A broad light retro-directing member on the opposite side of the objects from the light returns direct light back towards the source while directing other light away from the viewing point. The viewing point is offset from the light and thus receives only light which is forwardly scattered by an object while returning towards the source. The object is seen, at its true location, against a dark background. The invention is particularly adapted for illuminating and viewing nuclear particle tracks in a liquid hydrogen bubble chamber through a single chamber window. (AEC)

  17. Structured line illumination Raman microscopy

    PubMed Central

    Watanabe, Kozue; Palonpon, Almar F.; Smith, Nicholas I.; Chiu, Liang-da; Kasai, Atsushi; Hashimoto, Hitoshi; Kawata, Satoshi; Fujita, Katsumasa

    2015-01-01

    In the last couple of decades, the spatial resolution in optical microscopy has increased to unprecedented levels by exploiting the fluorescence properties of the probe. At about the same time, Raman imaging techniques have emerged as a way to image inherent chemical information in a sample without using fluorescent probes. However, in many applications, the achievable resolution is limited to about half the wavelength of excitation light. Here we report the use of structured illumination to increase the spatial resolution of label-free spontaneous Raman microscopy, generating highly detailed spatial contrast from the ensemble of molecular information in the sample. Using structured line illumination in slit-scanning Raman microscopy, we demonstrate a marked improvement in spatial resolution and show the applicability to a range of samples, including both biological and inorganic chemical component mapping. This technique is expected to contribute towards greater understanding of chemical component distributions in organic and inorganic materials. PMID:26626144

  18. Lunar-illuminated outdoor hologram

    NASA Astrophysics Data System (ADS)

    Jepsen, Mary Lou; Dawson, Paula H.

    1992-05-01

    The first step in the construction of a very deep, large source size, white light illuminated hologram is discussed. We outline the steps taken thus far in the creation of our computer- generated master hologram slit. Our goal is to computer generate a 2 meter master slit for optical transfer via Benton rainbow holography technique. The transfer hologram will ultimately be re-illuminated by the moon and fill a space of approximately 8000 cubic meters. Discussion of the relative merits of synthetic stereographic methods and CGH methods is presented as well as several novel hybrid techniques. The CGH test prints thus far created are evaluated for several types of aberrations and methods of pre-distortion and distortion correction are proposed.

  19. Illumination box and camera system

    DOEpatents

    Haas, Jeffrey S.; Kelly, Fredrick R.; Bushman, John F.; Wiefel, Michael H.; Jensen, Wayne A.; Klunder, Gregory L.

    2002-01-01

    A hand portable, field-deployable thin-layer chromatography (TLC) unit and a hand portable, battery-operated unit for development, illumination, and data acquisition of the TLC plates contain many miniaturized features that permit a large number of samples to be processed efficiently. The TLC unit includes a solvent tank, a holder for TLC plates, and a variety of tool chambers for storing TLC plates, solvent, and pipettes. After processing in the TLC unit, a TLC plate is positioned in a collapsible illumination box, where the box and a CCD camera are optically aligned for optimal pixel resolution of the CCD images of the TLC plate. The TLC system includes an improved development chamber for chemical development of TLC plates that prevents solvent overflow.

  20. Illumination influences working memory: an EEG study.

    PubMed

    Park, Jin Young; Min, Byoung-Kyong; Jung, Young-Chul; Pak, Hyensou; Jeong, Yeon-Hong; Kim, Eosu

    2013-09-05

    Illumination conditions appear to influence working efficacy in everyday life. In the present study, we obtained electroencephalogram (EEG) correlates of working-memory load, and investigated how these waveforms are modulated by illumination conditions. We hypothesized that illumination conditions may affect cognitive performance. We designed an EEG study to monitor and record participants' EEG during the Sternberg working memory task under four different illumination conditions. Illumination conditions were generated with a factorial design of two color-temperatures (3000 and 7100 K) by two illuminance levels (150 and 700 lx). During a working memory task, we observed that high illuminance led to significantly lower frontal EEG theta activity than did low illuminance. These differences persisted despite no significant difference in task performance between illumination conditions. We found that the latency of an early event-related potential component, such as N1, was significantly modulated by the illumination condition. The fact that the illumination condition affects brain activity but not behavioral performance suggests that the lighting conditions used in the present study did not influence the performance stage of behavioral processing. Nevertheless, our findings provide objective evidence that illumination conditions modulate brain activity. Further studies are necessary to refine the optimal lighting parameters for facilitating working memory.

  1. Applications of TM polarized illumination

    NASA Astrophysics Data System (ADS)

    Smith, Bruce; Zhou, Jianming; Xie, Peng

    2008-03-01

    The use of transverse electric (TE) polarization has dominated illumination schemes as selective polarization is used for high-NA patterning. The benefits of TE polarization are clear - the interference of diffracted beams remains absolute at oblique angles. Transverse magnetic (TM) polarization is usually considered less desirable as imaging modulation from interference at large angle falls off rapidly as the 1/cosθ. Significant potential remains, however, for the use of TM polarization at large angles when its reflection component is utilized. By controlling the resist/substrate interface reflectivity, high modulation for TM polarization can be maintained for angles up to 90° in the resist. This can potentially impact the design of illumination away from most recent TE-only schemes for oblique imaging angles (high NA). We demonstrate several cases of TM illumination combined with tuned substrate reflectivity for 0.93NA, 1.20NA, and 1.35NA and compare results to TE and unpolarized cases. The goal is to achieve a flat response through polarization at large imaging angles. An additional application of TM illumination is its potential use for double patterning. As double patterning and double exposure approaches are sought in order to meet the needs of 32nm device generations and beyond, materials and process engineering challenges become prohibitive. We have devised a method for frequency doubling in a single exposure using an unconventional means of polarization selection and by making use of the reflective component produced at the photoresist/substrate interface. In doing so, patterns can be deposited into a photoresist film with double density. As an example, using a projection system numerical aperture of 1.20, with water as an immersion fluid, and a conventional polyacrylate 193nm photoresist, pattern resolution at 20nm half-pitch are obtainable (which is 0.125lambda/NA). The process to transfer this geometry into a hardmask layer uses conventional materials

  2. Synchrotron-based EUV lithography illuminator simulator

    DOEpatents

    Naulleau, Patrick P.

    2004-07-27

    A lithographic illuminator to illuminate a reticle to be imaged with a range of angles is provided. The illumination can be employed to generate a pattern in the pupil of the imaging system, where spatial coordinates in the pupil plane correspond to illumination angles in the reticle plane. In particular, a coherent synchrotron beamline is used along with a potentially decoherentizing holographic optical element (HOE), as an experimental EUV illuminator simulation station. The pupil fill is completely defined by a single HOE, thus the system can be easily modified to model a variety of illuminator fill patterns. The HOE can be designed to generate any desired angular spectrum and such a device can serve as the basis for an illuminator simulator.

  3. Atmospheric effects on active illumination

    NASA Astrophysics Data System (ADS)

    Shaw, Scot E. J.; Kansky, Jan E.

    2005-08-01

    For some beam-control applications, we can rely on the cooperation of the target when gathering information about the target location and the state of the atmosphere between the target and the beam-control system. The typical example is a cooperative point-source beacon on the target. Light from such a beacon allows the beam-control system to track the target accurately, and, if higher-order adaptive optics is to be employed, to make wave-front measurements and apply appropriate corrections with a deformable mirror. In many applications, including directed-energy weapons, the target is not cooperative. In the absence of a cooperative beacon, we must find other ways to collect the relevant information. This can be accomplished with an active-illumination system. Typically, this means shining one or more lasers at the target and observing the reflected light. In this paper, we qualitatively explore a number of difficulties inherent to active illumination, and suggest some possible mitigation techniques.

  4. Segmentation and estimation of spatially varying illumination.

    PubMed

    Lin Gu; Huynh, Cong Phuoc; Robles-Kelly, Antonio

    2014-08-01

    In this paper, we present an unsupervised method for segmenting the illuminant regions and estimating the illumination power spectrum from a single image of a scene lit by multiple light sources. Here, illuminant region segmentation is cast as a probabilistic clustering problem in the image spectral radiance space. We formulate the problem in an optimization setting, which aims to maximize the likelihood of the image radiance with respect to a mixture model while enforcing a spatial smoothness constraint on the illuminant spectrum. We initialize the sample pixel set under each illuminant via a projection of the image radiance spectra onto a low-dimensional subspace spanned by a randomly chosen subset of spectra. Subsequently, we optimize the objective function in a coordinate-ascent manner by updating the weights of the mixture components, sample pixel set under each illuminant, and illuminant posterior probabilities. We then estimate the illuminant power spectrum per pixel making use of these posterior probabilities. We compare our method with a number of alternatives for the tasks of illumination region segmentation, illumination color estimation, and color correction. Our experiments show the effectiveness of our method as applied to one hyperspectral and three trichromatic image data sets.

  5. Background illumination and automated perimetry.

    PubMed

    Klewin, K M; Radius, R L

    1986-03-01

    Visual field function in the right and left eyes of 31 normal volunteers was evaluated with an automated projection perimeter (OCTOPUS). Serial visual field evaluations were repeated in these same eyes with neutral filters of increasing optical density. We compared the results of threshold determinations with the different neutral filters in place before the examined eye. Significant reduction in threshold sensitivity at several test spots throughout the central 30 degrees visual field was seen with neutral density filters of 0.5 log units or greater. The low level of background illumination of the OCTOPUS perimeter (4.0 apostilbs) may allow relatively minor reduction in light transmission by the ocular media to produce significant changes in the recorded level of threshold sensitivity during visual field evaluation.

  6. Fully depleted back illuminated CCD

    DOEpatents

    Holland, Stephen Edward

    2001-01-01

    A backside illuminated charge coupled device (CCD) is formed of a relatively thick high resistivity photon sensitive silicon substrate, with frontside electronic circuitry, and an optically transparent backside ohmic contact for applying a backside voltage which is at least sufficient to substantially fully deplete the substrate. A greater bias voltage which overdepletes the substrate may also be applied. One way of applying the bias voltage to the substrate is by physically connecting the voltage source to the ohmic contact. An alternate way of applying the bias voltage to the substrate is to physically connect the voltage source to the frontside of the substrate, at a point outside the depletion region. Thus both frontside and backside contacts can be used for backside biasing to fully deplete the substrate. Also, high resistivity gaps around the CCD channels and electrically floating channel stop regions can be provided in the CCD array around the CCD channels. The CCD array forms an imaging sensor useful in astronomy.

  7. Free-form illumination optics

    NASA Astrophysics Data System (ADS)

    Mohedano, Rubén; Chaves, Julio; Hernández, Maikel

    2016-04-01

    In many illumination problems, the beam pattern needed and/or some geometrical constraints lead to very asymmetric design conditions. These asymmetries have been solved in the past by means of arrangements of rotationally symmetric or linear lamps aimed in different directions whose patterns overlap to provide the asymmetric prescriptions or by splitting one single lamp into several sections, each one providing a part of the pattern. The development of new design methods yielding smooth continuous free-form optical surfaces to solve these challenging design problems, combined with the proper CAD modeling tools plus the development of multiple axes diamond turn machines, give birth to a new generation of optics. These are able to offer the performance and other advanced features, such as efficiency, compactness, or aesthetical advantages, and can be manufactured at low cost by injection molding. This paper presents two examples of devices with free-form optical surfaces, a camera flash, and a car headlamp.

  8. Off-axis illumination of lithography tool

    NASA Astrophysics Data System (ADS)

    Xing, Han; Lin, Li; Bin, Ma

    2013-12-01

    Lithography tool is a necessary part for LSI and VLSI. The illumination system design is an important part in the lithography optical system design. Off-axis illumination technology is an effective way to reducing resolution of lithography. The paper introduction the basic components of lithography tool, the principle of off-axis illumination reducing the resolution of lithography and focus on the two implementations of OAI technology, finally point out advantages and disadvantage of the two implementations.

  9. Improved Interference configuration for structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Chen, Houkai; Wei, Shibiao; Wu, Xiaojing; Yang, Yong; Zhang, Yuquan; Du, Luping; Liu, Jun; Zhu, Siwei; Yuan, Xiaocong

    2017-02-01

    We present an improved structured illumination configuration for structured illumination microscopy (SIM) based on spatial light modulator. Precise phase shifts and rotation of illumination fringes can be dynamically controlled using a spatial light modulator. The method is different from the conventional illumination configuration that are based on interference of ±1 diffractive order light. The experimental setup requires less optical elements making it compact, reliable, and suitable for integration. The method has been applied in the standing-wave total internal reflection fluorescent microscopy. High lateral resolution of sub-100 nm was achieved in single directional resolution enhancement experiments.

  10. Polarimetric target detection under uneven illumination.

    PubMed

    Huang, Bingjing; Liu, Tiegen; Han, Jiahui; Hu, Haofeng

    2015-09-07

    In polarimetric imaging, the uneven illumination could cause the significant spatial intensity fluctuations in the scene, and thus hampers the target detection. In this paper, we propose a method of illumination compensation and contrast optimization for Stokes polarimetric imaging, which allows significantly increasing the performance of target detection under uneven illumination. We show with numerical simulation and real-world experiment that, based on the intensity information contained in the polarization information, the contrast can be effectively enhanced by proper approach, which is of particular importance in practical applications with spatial illumination fluctuations, such as remote sensing.

  11. Illumination system characterization for hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Katrašnik, Jaka; Pernuš, Franjo; Likar, Boštjan

    2011-03-01

    Near-infrared hyperspectral imaging is becoming a popular tool in the biomedical field, especially for detection and analysis of different types of cancers, analysis of skin burns and bruises, imaging of blood vessels and for many other applications. As in all imaging systems, proper illumination is crucial to attain optimal image quality that is needed for best performance of image analysis algorithms. In hyperspectral imaging based on filters (AOTF, LCTF and filter wheel) the acquired spectral signature has to be representative in all parts of the imaged object. Therefore, the whole object must be equally well illuminated - without shadows and specular reflections. As there are no restrictions imposed on the material and geometry of the object, the desired object illumination can only be achieved with completely diffuse illumination. In order to minimize shadows and specular reflections in diffuse illumination the light illuminating the object must be spatially, angularly and spectrally uniform. We present and test two diffuse illumination system designs that try to achieve optimal uniformity of the above mentioned properties. The illumination uniformity properties were measured with an AOTF based hyperspectral imaging system utilizing a standard white diffuse reflectance target and a specially designed calibration target for estimating the spatial and angular illumination uniformity.

  12. Structured illumination fluorescence Fourier ptychographic microscopy

    NASA Astrophysics Data System (ADS)

    Xiu, Peng; Chen, Youhua; Kuang, Cuifang; Fang, Yue; Wang, Yifan; Fan, Jiannan; Xu, Yingke; Liu, Xu

    2016-12-01

    We apply a Fourier ptychographic algorithm for fluorescent samples using structured illumination. The samples are illuminated with structured light patterns and the raw imaging data using traditional structured illumination fluorescence microscopy (SIM) are acquired. We then extract equivalent oblique illuminated images of fluorescent samples from the SIM images. An optimized Fourier ptychography algorithm is proposed, which ensures the fidelity of the reconstructed the super-resolution results. This method can break the diffraction limit to a resolution of λ/4, and has a better signal-to-noise ratio (SNR) than SIM, especially when the background noise is high.

  13. Illumination discrimination in real and simulated scenes

    PubMed Central

    Radonjić, Ana; Pearce, Bradley; Aston, Stacey; Krieger, Avery; Dubin, Hilary; Cottaris, Nicolas P.; Brainard, David H.; Hurlbert, Anya C.

    2016-01-01

    Characterizing humans' ability to discriminate changes in illumination provides information about the visual system's representation of the distal stimulus. We have previously shown that humans are able to discriminate illumination changes and that sensitivity to such changes depends on their chromatic direction. Probing illumination discrimination further would be facilitated by the use of computer-graphics simulations, which would, in practice, enable a wider range of stimulus manipulations. There is no a priori guarantee, however, that results obtained with simulated scenes generalize to real illuminated scenes. To investigate this question, we measured illumination discrimination in real and simulated scenes that were well-matched in mean chromaticity and scene geometry. Illumination discrimination thresholds were essentially identical for the two stimulus types. As in our previous work, these thresholds varied with illumination change direction. We exploited the flexibility offered by the use of graphics simulations to investigate whether the differences across direction are preserved when the surfaces in the scene are varied. We show that varying the scene's surface ensemble in a manner that also changes mean scene chromaticity modulates the relative sensitivity to illumination changes along different chromatic directions. Thus, any characterization of sensitivity to changes in illumination must be defined relative to the set of surfaces in the scene.

  14. Illumination preference, illumination constancy and colour discrimination by bumblebees in an environment with patchy light.

    PubMed

    Arnold, Sarah E J; Chittka, Lars

    2012-07-01

    Patchy illumination presents foraging animals with a challenge, as the targets being sought may appear to vary in colour depending on the illumination, compromising target identification. We sought to explore how the bumblebee Bombus terrestris copes with tasks involving flower colour discrimination under patchy illumination. Light patches varied between unobscured daylight and leaf-shade, as a bee might encounter in and around woodland. Using a flight arena and coloured filters, as well as one or two different colours of artificial flower, we quantified how bees chose to forage when presented with foraging tasks under patchy illumination. Bees were better at discriminating a pair of similar colours under simulated unobscured daylight illumination than when foraging under leaf-shade illumination. Accordingly, we found that bees with prior experience of simulated daylight but not leaf-shade illumination initially preferred to forage in simulated daylight when all artificial flowers contained rewards as well as when only one colour was rewarding, whereas bees with prior experience of both illuminants did not exhibit this preference. Bees also switched between illuminants less than expected by chance. This means that bees prefer illumination conditions with which they are familiar, and in which rewarding flower colours are easily distinguishable from unrewarding ones. Under patchy illumination, colour discrimination performance was substantially poorer than in homogenous light. The bees' abilities at coping with patchy light may therefore impact on foraging behaviour in the wild, particularly in woodlands, where illumination can change over short spatial scales.

  15. Secure communication via quantum illumination

    NASA Astrophysics Data System (ADS)

    Shapiro, Jeffrey H.; Zhang, Zheshen; Wong, Franco N. C.

    2014-10-01

    In the quantum illumination protocol for secure communication, Alice prepares entangled signal and idler beams via spontaneous parametric downconversion. She sends the signal beam to Bob, while retaining the idler. Bob imposes message modulation on the beam he receives from Alice, amplifies it, and sends it back to her. Alice then decodes Bob's information by making a joint quantum measurement on the light she has retained and the light she has received from him. The basic performance analysis for this protocol—which demonstrates its immunity to passive eavesdropping, in which Eve can only listen to Alice and Bob's transmissions—is reviewed, along with the results of its first proof-of-principle experiment. Further analysis is then presented, showing that secure data rates in excess of 1 Gbps may be possible over 20-km-long fiber links with technology that is available or under development. Finally, an initial scheme for thwarting active eavesdropping, in which Eve injects her own light into Bob's terminal, is proposed and analyzed.

  16. 3D structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Dougherty, William M.; Goodwin, Paul C.

    2011-03-01

    Three-dimensional structured illumination microscopy achieves double the lateral and axial resolution of wide-field microscopy, using conventional fluorescent dyes, proteins and sample preparation techniques. A three-dimensional interference-fringe pattern excites the fluorescence, filling in the "missing cone" of the wide field optical transfer function, thereby enabling axial (z) discrimination. The pattern acts as a spatial carrier frequency that mixes with the higher spatial frequency components of the image, which usually succumb to the diffraction limit. The fluorescence image encodes the high frequency content as a down-mixed, moiré-like pattern. A series of images is required, wherein the 3D pattern is shifted and rotated, providing down-mixed data for a system of linear equations. Super-resolution is obtained by solving these equations. The speed with which the image series can be obtained can be a problem for the microscopy of living cells. Challenges include pattern-switching speeds, optical efficiency, wavefront quality and fringe contrast, fringe pitch optimization, and polarization issues. We will review some recent developments in 3D-SIM hardware with the goal of super-resolved z-stacks of motile cells.

  17. Extinction-Optimized Volume Illumination.

    PubMed

    Ament, Marco; Zirr, Tobias; Dachsbacher, Carsten

    2016-05-16

    We present a novel method to optimize the attenuation of light for the single scattering model in direct volume rendering. A common problem of single scattering is the high dynamic range between lit and shadowed regions due to the exponential attenuation of light along a ray. Moreover, light is often attenuated too strong between a sample point and the camera, hampering the visibility of important features. Our algorithm employs an importance function to selectively illuminate important structures and make them visible from the camera. With the importance function, more light can be transmitted to the features of interest, while contextual structures cast shadows which provide visual cues for perception of depth. At the same time, more scattered light is transmitted from the sample point to the camera to improve the primary visibility of important features. We formulate a minimization problem that automatically determines the extinction along a view or shadow ray to obtain a good balance between sufficient transmittance and attenuation. In contrast to previous approaches, we do not require a computationally expensive solution of a global optimization, but instead provide a closed-form solution for each sampled extinction value along a view or shadow ray and thus achieve interactive performance.

  18. 29 CFR 1926.56 - Illumination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... shall be lighted to not less than the minimum illumination intensities listed in Table D-3 while any work is in progress: Table D-3—Minimum Illumination Intensities in Foot-Candles Foot-candles Area or... drilling, mucking, and scaling. Bureau of Mines approved cap lights shall be acceptable for use in...

  19. 29 CFR 1926.56 - Illumination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... shall be lighted to not less than the minimum illumination intensities listed in Table D-3 while any work is in progress: Table D-3—Minimum Illumination Intensities in Foot-Candles Foot-candles Area or... drilling, mucking, and scaling. Bureau of Mines approved cap lights shall be acceptable for use in...

  20. Translating Rimbaud's "Illuminations": Games with Words

    ERIC Educational Resources Information Center

    Slote, Daniel

    1978-01-01

    Rimbaud's "Illuminations," one vast word-game, is used as an example of one of the most interesting challenges in translation--the rendering of plays on words. The process is discussed and illustrated by the analysis of numerous segments from "Illuminations." It is concluded that a satisfactory translation is almost impossible.…

  1. Reflectance and Illumination Recovery in the Wild.

    PubMed

    Lombardi, Stephen; Nishino, Ko

    2016-01-01

    The appearance of an object in an image encodes invaluable information about that object and the surrounding scene. Inferring object reflectance and scene illumination from an image would help us decode this information: reflectance can reveal important properties about the materials composing an object; the illumination can tell us, for instance, whether the scene is indoors or outdoors. Recovering reflectance and illumination from a single image in the real world, however, is a difficult task. Real scenes illuminate objects from every visible direction and real objects vary greatly in reflectance behavior. In addition, the image formation process introduces ambiguities, like color constancy, that make reversing the process ill-posed. To address this problem, we propose a Bayesian framework for joint reflectance and illumination inference in the real world. We develop a reflectance model and priors that precisely capture the space of real-world object reflectance and a flexible illumination model that can represent real-world illumination with priors that combat the deleterious effects of image formation. We analyze the performance of our approach on a set of synthetic data and demonstrate results on real-world scenes. These contributions enable reliable reflectance and illumination inference in the real world.

  2. Illuminant spectrum estimation at a pixel.

    PubMed

    Ratnasingam, Sivalogeswaran; Hernández-Andrés, Javier

    2011-04-01

    In this paper, an algorithm is proposed to estimate the spectral power distribution of a light source at a pixel. The first step of the algorithm is forming a two-dimensional illuminant invariant chromaticity space. In estimating the illuminant spectrum, generalized inverse estimation and Wiener estimation methods were applied. The chromaticity space was divided into small grids and a weight matrix was used to estimate the illuminant spectrum illuminating the pixels that fall within a grid. The algorithm was tested using a different number of sensor responses to determine the optimum number of sensors for accurate colorimetric and spectral reproduction. To investigate the performance of the algorithm realistically, the responses were multiplied with Gaussian noise and then quantized to 10 bits. The algorithm was tested with standard and measured data. Based on the results presented, the algorithm can be used with six sensors to obtain a colorimetrically good estimate of the illuminant spectrum at a pixel.

  3. Chromatic illumination discrimination ability reveals that human colour constancy is optimised for blue daylight illuminations.

    PubMed

    Pearce, Bradley; Crichton, Stuart; Mackiewicz, Michal; Finlayson, Graham D; Hurlbert, Anya

    2014-01-01

    The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

  4. Chromatic Illumination Discrimination Ability Reveals that Human Colour Constancy Is Optimised for Blue Daylight Illuminations

    PubMed Central

    Pearce, Bradley; Crichton, Stuart; Mackiewicz, Michal; Finlayson, Graham D.; Hurlbert, Anya

    2014-01-01

    The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed. PMID:24586299

  5. Long-range laser-illuminated imaging

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Browne, Stephen L.; Sandven, Steven C.; Gonglewski, John D.; Gallegos, Joe; Shilko, Michael L., Sr.

    2000-11-01

    We demonstrate the utility of laser illuminated imaging for clandestine night time surveillance from a simulated airborne platform at standoff ranges in excess 20 km. In order to reduce the necessary laser per pulse energy required for illumination at such long ranges, and to mitigate atmospheric turbulence effects on image resolution, we have investigated a unique multi-frame post-processing technique. It is shown that in the presence of atmospheric turbulence and coherent speckle effects, this approach can produce superior results to conventional scene flood illumination.

  6. Saturated pattern-illuminated Fourier ptychography microscopy

    NASA Astrophysics Data System (ADS)

    Fang, Yue; Chen, Youhua; Kuang, Cuifang; Xiu, Peng; Liu, Qiulan; Ge, Baoliang; Liu, Xu

    2017-01-01

    We report a series of simulation studies which extends pattern-illuminated Fourier ptychography microscopy by integrating with the nonlinearity arising from saturation of the fluorophore excited state for super-resolution fluorescence imaging. This extended technique, termed Saturated pattern-illuminated Fourier ptychography (SpiFP) microscopy, could achieve a resolution four times that of wide field when the illuminating light intensity approaches the saturation threshold in simulations. Increasing light intensity leads to further resolution enhancement. In order to demonstrate the performance of SpiFP, we make a comparison between SpiFP and saturated structure illumination microscopy in simulations, and prove that the SpiFP exhibits superior robustness to noise, aberration correcting ability, and pattern’s flexibility. Introducing the saturation of the fluorescent emission brings in notable improvements in imaging performance, implying its potential in nanoscale-sized biological observations by wide-field microscopy.

  7. Illumination control apparatus for compensating solar light

    NASA Technical Reports Server (NTRS)

    Owens, L. J. (Inventor)

    1978-01-01

    An illumination control apparatus is presented for supplementing light from solar radiation with light from an artificial light source to compensate for periods of insufficient levels of solar light. The apparatus maintains a desired illumination level within an interior space comprising an artificial light source connected to an electrical power source with a switch means for selectively energizing said light source. An actuator means for controlling the on-off operation of the switch means is connected to a light sensor which responses to the illumination level of the interior space. A limit switch carried adjacent to the actuator limits the movement of the actuator within a predetermined range so as to prevent further movement thereof during detection of erroneous illumination conditions.

  8. The Freeform Reflector for Uniform Rectangular Illumination

    NASA Astrophysics Data System (ADS)

    Ding, Yi; Gu, Pei-Fu; Zheng, Zhen-Rong

    2007-12-01

    Energy from the source was rearranged through reflection by a freeform reflector, in order to get uniform rectangular illumination. The numerical results of partial differential equation sets were investigated to obtain the freeform reflector and these equations were obtained upon the determination of the characters of source and the desired illumination. As an example, a light emitting diode (LED) with a Lambertian light-emitting surface of 1 × 1 mm2 and a viewing angle of 120° was applied as the source, and the target plane was a 4:3 rectangle with uniform illumination. The projective length of the reflector on x-axis is about 23 mm, and on y-axis is about 21 mm. Thus the illumination system is very compact.

  9. An illuminated flute needle for vitreoretinal surgery.

    PubMed

    Davison, C N; Rosen, P H

    1994-06-01

    We have developed a simple self-illuminated flute needle for internal drainage of subretinal fluid during three-port vitrectomy. This instrument facilitates visualization and drainage through peripheral retinal breaks.

  10. 49 CFR 230.86 - Required illumination.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... provides illumination sufficient for a steam locomotive engineer in the cab to see, in a clear atmosphere... other than to pick up a detached portion of its train or to make terminal movements, it shall also...

  11. 49 CFR 230.86 - Required illumination.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... provides illumination sufficient for a steam locomotive engineer in the cab to see, in a clear atmosphere... other than to pick up a detached portion of its train or to make terminal movements, it shall also...

  12. 49 CFR 230.86 - Required illumination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... provides illumination sufficient for a steam locomotive engineer in the cab to see, in a clear atmosphere... other than to pick up a detached portion of its train or to make terminal movements, it shall also...

  13. Insulator Surface Flashover Due to UV Illumination

    DTIC Science & Technology

    2009-06-01

    The surface of an insulator under vacuum and under electrical charge will flashover when illuminated by a critical dose of ultra-violet (UV...fluence (energy per unit area) required to induce surface flashover of vacuum insulators for some candid insulator materials: High Density... Insulator Surface Flashover Due to UV Illumination1 J. B. Javedani, T.L. Houck, D.A. Lahowe, G.E. Vogtlin and D.A. Goerz Lawrence Livermore

  14. Surface color perception under two illuminants: the second illuminant reduces color constancy

    NASA Technical Reports Server (NTRS)

    Yang, Joong Nam; Shevell, Steven K.

    2003-01-01

    This study investigates color perception in a scene with two different illuminants. The two illuminants, in opposite corners, simultaneously shine on a (simulated) scene with an opaque dividing wall, which controls how much of the scene is illuminated by each source. In the first experiment, the height of the dividing wall was varied. This changed the amount of each illuminant reaching objects on the opposite side of the wall. Results showed that the degree of color constancy decreased when a region on one side of the wall had cues to both illuminants, suggesting that cues from the second illuminant are detrimental to color constancy. In a later experiment, color constancy was found to improve when the specular highlight cues from the second illuminant were altered to be consistent with the first illuminant. This corroborates the influence of specular highlights in surface color perception, and suggests that the reduced color constancy in the first experiment is due to the inconsistent, though physically correct, cues from the two illuminants.

  15. Deterministic phase retrieval employing spherical illumination

    NASA Astrophysics Data System (ADS)

    Martínez-Carranza, J.; Falaggis, K.; Kozacki, T.

    2015-05-01

    Deterministic Phase Retrieval techniques (DPRTs) employ a series of paraxial beam intensities in order to recover the phase of a complex field. These paraxial intensities are usually generated in systems that employ plane-wave illumination. This type of illumination allows a direct processing of the captured intensities with DPRTs for recovering the phase. Furthermore, it has been shown that intensities for DPRTs can be acquired from systems that use spherical illumination as well. However, this type of illumination presents a major setback for DPRTs: the captured intensities change their size for each position of the detector on the propagation axis. In order to apply the DPRTs, reescalation of the captured intensities has to be applied. This condition can increase the error sensitivity of the final phase result if it is not carried out properly. In this work, we introduce a novel system based on a Phase Light Modulator (PLM) for capturing the intensities when employing spherical illumination. The proposed optical system enables us to capture the diffraction pattern of under, in, and over-focus intensities. The employment of the PLM allows capturing the corresponding intensities without displacing the detector. Moreover, with the proposed optical system we can control accurately the magnification of the captured intensities. Thus, the stack of captured intensities can be used in DPRTs, overcoming the problems related with the resizing of the images. In order to prove our claims, the corresponding numerical experiments will be carried out. These simulations will show that the retrieved phases with spherical illumination are accurate and can be compared with those that employ plane wave illumination. We demonstrate that with the employment of the PLM, the proposed optical system has several advantages as: the optical system is compact, the beam size on the detector plane is controlled accurately, and the errors coming from mechanical motion can be suppressed easily.

  16. Lunar Polar Illumination for Power Analysis

    NASA Technical Reports Server (NTRS)

    Fincannon, James

    2008-01-01

    This paper presents illumination analyses using the latest Earth-based radar digital elevation model (DEM) of the lunar south pole and an independently developed analytical tool. These results enable the optimum sizing of solar/energy storage lunar surface power systems since they quantify the timing and durations of illuminated and shadowed periods. Filtering and manual editing of the DEM based on comparisons with independent imagery were performed and a reduced resolution version of the DEM was produced to reduce the analysis time. A comparison of the DEM with lunar limb imagery was performed in order to validate the absolute heights over the polar latitude range, the accuracy of which affects the impact of long range, shadow-casting terrain. Average illumination and energy storage duration maps of the south pole region are provided for the worst and best case lunar day using the reduced resolution DEM. Average illumination fractions and energy storage durations are presented for candidate low energy storage duration south pole sites. The best site identified using the reduced resolution DEM required a 62 hr energy storage duration using a fast recharge power system. Solar and horizon terrain elevations as well as illumination fraction profiles are presented for the best identified site and the data for both the reduced resolution and high resolution DEMs compared. High resolution maps for three low energy storage duration areas are presented showing energy storage duration for the worst case lunar day, surface height, and maximum absolute surface slope.

  17. 30 CFR 57.17001 - Illumination of surface working areas.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Illumination of surface working areas. 57.17001... Illumination § 57.17001 Illumination of surface working areas. Illumination sufficient to provide safe working conditions shall be provided in and on all surface structures, paths, walkways, stairways, switch...

  18. 10 CFR 431.202 - Definitions concerning illuminated exit signs.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning illuminated exit signs. 431.202... COMMERCIAL AND INDUSTRIAL EQUIPMENT Illuminated Exit Signs § 431.202 Definitions concerning illuminated exit signs. Basic model means, with respect to illuminated exit signs, all units of a given type...

  19. 10 CFR 431.202 - Definitions concerning illuminated exit signs.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Definitions concerning illuminated exit signs. 431.202... COMMERCIAL AND INDUSTRIAL EQUIPMENT Illuminated Exit Signs § 431.202 Definitions concerning illuminated exit signs. Basic model means, with respect to illuminated exit signs, all units of a given type...

  20. 30 CFR 57.17001 - Illumination of surface working areas.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Illumination of surface working areas. 57.17001... Illumination § 57.17001 Illumination of surface working areas. Illumination sufficient to provide safe working conditions shall be provided in and on all surface structures, paths, walkways, stairways, switch...

  1. 30 CFR 56.17001 - Illumination of surface working areas.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Illumination of surface working areas. 56.17001... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Illumination § 56.17001 Illumination of surface working areas. Illumination sufficient to provide safe...

  2. Content adaptive illumination for Fourier ptychography.

    PubMed

    Bian, Liheng; Suo, Jinli; Situ, Guohai; Zheng, Guoan; Chen, Feng; Dai, Qionghai

    2014-12-01

    Fourier ptychography (FP) is a recently reported technique, for large field-of-view and high-resolution imaging. Specifically, FP captures a set of low-resolution images, under angularly varying illuminations, and stitches them together in the Fourier domain. One of FP's main disadvantages is its long capturing process, due to the requisite large number of incident illumination angles. In this Letter, utilizing the sparsity of natural images in the Fourier domain, we propose a highly efficient method, termed adaptive Fourier ptychography (AFP), which applies content adaptive illumination for FP, to capture the most informative parts of the scene's spatial spectrum. We validate the effectiveness and efficiency of the reported framework, with both simulated and real experiments. Results show that the proposed AFP could shorten the acquisition time of conventional FP, by around 30%-60%.

  3. Contrast edge colors under different natural illuminations.

    PubMed

    Nieves, Juan Luis; Nascimento, Sérgio M C; Romero, Javier

    2012-02-01

    Essential to sensory processing in the human visual system is natural illumination, which can vary considerably not only across space but also along the day depending on the atmospheric conditions and the sun's position in the sky. In this work, edges derived from the three postreceptoral Luminance, Red-Green, and Blue-Yellow signals were computed from hyperspectral images of natural scenes rendered with daylights of Correlated Color Temperatures (CCTs) from 2735 to 25,889 K; for low CCT, the same analysis was performed using Planckian illuminants up to 800 K. It was found that average luminance and chromatic edge contrasts were maximal for low correlated color temperatures and almost constants above 10,000 K. The magnitude of these contrast changes was, however, only about 2% across the tested daylights. Results suggest that the postreceptoral opponent and nonopponent color vision mechanisms produce almost constant responses for color edge detection under natural illumination.

  4. Quantum Estimation Methods for Quantum Illumination

    NASA Astrophysics Data System (ADS)

    Sanz, M.; Las Heras, U.; García-Ripoll, J. J.; Solano, E.; Di Candia, R.

    2017-02-01

    Quantum illumination consists in shining quantum light on a target region immersed in a bright thermal bath with the aim of detecting the presence of a possible low-reflective object. If the signal is entangled with the receiver, then a suitable choice of the measurement offers a gain with respect to the optimal classical protocol employing coherent states. Here, we tackle this detection problem by using quantum estimation techniques to measure the reflectivity parameter of the object, showing an enhancement in the signal-to-noise ratio up to 3 dB with respect to the classical case when implementing only local measurements. Our approach employs the quantum Fisher information to provide an upper bound for the error probability, supplies the concrete estimator saturating the bound, and extends the quantum illumination protocol to non-Gaussian states. As an example, we show how Schrödinger's cat states may be used for quantum illumination.

  5. Quantum Estimation Methods for Quantum Illumination.

    PubMed

    Sanz, M; Las Heras, U; García-Ripoll, J J; Solano, E; Di Candia, R

    2017-02-17

    Quantum illumination consists in shining quantum light on a target region immersed in a bright thermal bath with the aim of detecting the presence of a possible low-reflective object. If the signal is entangled with the receiver, then a suitable choice of the measurement offers a gain with respect to the optimal classical protocol employing coherent states. Here, we tackle this detection problem by using quantum estimation techniques to measure the reflectivity parameter of the object, showing an enhancement in the signal-to-noise ratio up to 3 dB with respect to the classical case when implementing only local measurements. Our approach employs the quantum Fisher information to provide an upper bound for the error probability, supplies the concrete estimator saturating the bound, and extends the quantum illumination protocol to non-Gaussian states. As an example, we show how Schrödinger's cat states may be used for quantum illumination.

  6. Illumination-compensated non-contact imaging photoplethysmography via dual-mode temporally coded illumination

    NASA Astrophysics Data System (ADS)

    Amelard, Robert; Scharfenberger, Christian; Wong, Alexander; Clausi, David A.

    2015-03-01

    Non-contact camera-based imaging photoplethysmography (iPPG) is useful for measuring heart rate in conditions where contact devices are problematic due to issues such as mobility, comfort, and sanitation. Existing iPPG methods analyse the light-tissue interaction of either active or passive (ambient) illumination. Many active iPPG methods assume the incident ambient light is negligible to the active illumination, resulting in high power requirements, while many passive iPPG methods assume near-constant ambient conditions. These assumptions can only be achieved in environments with controlled illumination and thus constrain the use of such devices. To increase the number of possible applications of iPPG devices, we propose a dual-mode active iPPG system that is robust to changes in ambient illumination variations. Our system uses a temporally-coded illumination sequence that is synchronized with the camera to measure both active and ambient illumination interaction for determining heart rate. By subtracting the ambient contribution, the remaining illumination data can be attributed to the controlled illuminant. Our device comprises a camera and an LED illuminant controlled by a microcontroller. The microcontroller drives the temporal code via synchronizing the frame captures and illumination time at the hardware level. By simulating changes in ambient light conditions, experimental results show our device is able to assess heart rate accurately in challenging lighting conditions. By varying the temporal code, we demonstrate the trade-off between camera frame rate and ambient light compensation for optimal blood pulse detection.

  7. Concentrated and piped sunlight for indoor illumination.

    PubMed

    Fraas, L M; Pyle, W R; Ryason, P R

    1983-02-15

    A concept for indoor illumination of buildings using sunlight is described. For this system, a tracking concentrator on the building roof follows the sun and focuses sunlight into a lightguide. A system of transparent lightguides distributes the sunlight to interior rooms. Recent advances in the transparency of acrylic plastic optical fibers suggest that acrylic lightguides could be successfully used for piping sunlight. The proposed system displaces electricity currently used for indoor lighting. It is argued that using sunlight directly for indoor illumination would be about twenty-five times more cost-effective than using sunlight to generate electricity with solar cells for powering electric lamps for indoor lighting.

  8. Organic light emitting devices for illumination

    DOEpatents

    Hack, Michael [Lambertville, NJ; Lu, Min-Hao Michael [Lawrenceville, NJ; Weaver, Michael S [Princeton, NJ

    2012-01-24

    An organic light emitting device an a method of obtaining illumination from such a device is provided. The device has a plurality of regions, each region having an organic emissive layer adapted to emit a different spectrum of light. The regions in combination emit light suitable for illumination purposes. The area of each region may be selected such that the device is more efficient than an otherwise equivalent device having regions of equal size. The regions may have an aspect ratio of at least about four. All parts of any given region may be driven at the same current.

  9. Resolution enhancement using simultaneous couple illumination

    NASA Astrophysics Data System (ADS)

    Hussain, Anwar; Martínez Fuentes, José Luis

    2016-10-01

    A super-resolution technique based on structured illumination created by a liquid crystal on silicon spatial light modulator (LCOS-SLM) is presented. Single and simultaneous pairs of tilted beams are generated to illuminate a target object. Resolution enhancement of an optical 4f system is demonstrated by using numerical simulations. The resulting intensity images are recorded at a charged couple device (CCD) and stored in the computer memory for further processing. One dimension enhancement can be performed with only 15 images. Two dimensional complete improvement requires 153 different images. The resolution of the optical system is extended three times compared to the band limited system.

  10. Fiber-type dosimeter with improved illuminator

    DOEpatents

    Fox, Richard J.

    1987-01-01

    A single-piece, molded plastic, Cassigrainian-type condenser arrangement is incorporated in a tubular-shaped personal pocket dosimeter of the type which combines an ionization chamber with an optically-read fiber electrometer to provide improved illumination of the electrometer fiber. The condenser routes incoming light from one end of the dosimeter tubular housing around a central axis charging pin assembly and focuses the light at low angles to the axis so that it falls within the acceptance angle of the electrometer fiber objective lens viewed through an eyepiece lens disposed in the opposite end of the dosimeter. This results in improved fiber illumination and fiber image contrast.

  11. Fiber-type dosimeter with improved illuminator

    DOEpatents

    Fox, R.J.

    1985-12-23

    A single-piece, molded plastic, Cassigrainian-type condenser arrangement is incorporated in a tubular-shaped personal pocket dosimeter of the type which combines an ionization chamber with an optically-read fiber electrometer to provide improved illumination of the electrometer fiber. The condenser routes incoming light from one end of the dosimeter tubular housing around a central axis charging pin assembly and focuses the light at low angles to the axis so that it falls within the acceptance angle of the electrometer fiber objective lens viewed through an eyepiece lens disposed in the opposite end of the dosimeter. This results in improved fiber illumination and fiber image contrast.

  12. Fused off-axis object illumination direct-to-digital holography with a plurality of illumination sources

    DOEpatents

    Price, Jeffery R.; Bingham, Philip R.

    2005-11-08

    Systems and methods are described for rapid acquisition of fused off-axis illumination direct-to-digital holography. A method of recording a plurality of off-axis object illuminated spatially heterodyne holograms, each of the off-axis object illuminated spatially heterodyne holograms including spatially heterodyne fringes for Fourier analysis, includes digitally recording, with a first illumination source of an interferometer, a first off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; and digitally recording, with a second illumination source of the interferometer, a second off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis.

  13. Efficient illumination for microsecond tracking microscopy.

    PubMed

    Dulin, David; Barland, Stephane; Hachair, Xavier; Pedaci, Francesco

    2014-01-01

    The possibility to observe microsecond dynamics at the sub-micron scale, opened by recent technological advances in fast camera sensors, will affect many biophysical studies based on particle tracking in optical microscopy. A main limiting factor for further development of fast video microscopy remains the illumination of the sample, which must deliver sufficient light to the camera to allow microsecond exposure times. Here we systematically compare the main illumination systems employed in holographic tracking microscopy, and we show that a superluminescent diode and a modulated laser diode perform the best in terms of image quality and acquisition speed, respectively. In particular, we show that the simple and inexpensive laser illumination enables less than 1 μs camera exposure time at high magnification on a large field of view without coherence image artifacts, together with a good hologram quality that allows nm-tracking of microscopic beads to be performed. This comparison of sources can guide in choosing the most efficient illumination system with respect to the specific application.

  14. 29 CFR 1918.92 - Illumination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... operations, illumination for cargo transfer operations shall be of a minimum light intensity of five foot-candles (54 lux). Where work tasks require more light to be performed safely, supplemental lighting shall be used. (b) Intensity measurement. The lighting intensity shall be measured at the...

  15. 29 CFR 1918.92 - Illumination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... operations, illumination for cargo transfer operations shall be of a minimum light intensity of five foot-candles (54 lux). Where work tasks require more light to be performed safely, supplemental lighting shall be used. (b) Intensity measurement. The lighting intensity shall be measured at the...

  16. 29 CFR 1918.92 - Illumination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... operations, illumination for cargo transfer operations shall be of a minimum light intensity of five foot-candles (54 lux). Where work tasks require more light to be performed safely, supplemental lighting shall be used. (b) Intensity measurement. The lighting intensity shall be measured at the...

  17. 29 CFR 1918.92 - Illumination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... operations, illumination for cargo transfer operations shall be of a minimum light intensity of five foot-candles (54 lux). Where work tasks require more light to be performed safely, supplemental lighting shall be used. (b) Intensity measurement. The lighting intensity shall be measured at the...

  18. Adaptive Illumination Patterns for Radar Applications

    DTIC Science & Technology

    2006-03-01

    Losses . . . . . . . . . . . . . . . . . . . . . . . . . 44 Ri Range to the i th range ring . . . . . . . . . . . . . . . . . 44 R Signal-Dependent...Interval . . . . . . . . . . . . . . . . . . . 23 R /H Range-to-Height Ratio . . . . . . . . . . . . . . . . . . . . 51 RMB Reed Mallet and Brennan Rule...as follows: 16 AIP-TIPD Planar Array Radar Model Extensions I - I l r rr r l t i Space Time Illumination Patterns (STIP) i Ill i ti tt r ( I

  19. Lighting design for globally illuminated volume rendering.

    PubMed

    Zhang, Yubo; Ma, Kwan-Liu

    2013-12-01

    With the evolution of graphics hardware, high quality global illumination becomes available for real-time volume rendering. Compared to local illumination, global illumination can produce realistic shading effects which are closer to real world scenes, and has proven useful for enhancing volume data visualization to enable better depth and shape perception. However, setting up optimal lighting could be a nontrivial task for average users. There were lighting design works for volume visualization but they did not consider global light transportation. In this paper, we present a lighting design method for volume visualization employing global illumination. The resulting system takes into account view and transfer-function dependent content of the volume data to automatically generate an optimized three-point lighting environment. Our method fully exploits the back light which is not used by previous volume visualization systems. By also including global shadow and multiple scattering, our lighting system can effectively enhance the depth and shape perception of volumetric features of interest. In addition, we propose an automatic tone mapping operator which recovers visual details from overexposed areas while maintaining sufficient contrast in the dark areas. We show that our method is effective for visualizing volume datasets with complex structures. The structural information is more clearly and correctly presented under the automatically generated light sources.

  20. Diffuse-Illumination Systems for Growing Plants

    NASA Technical Reports Server (NTRS)

    May, George; Ryan, Robert

    2010-01-01

    Agriculture in both terrestrial and space-controlled environments relies heavily on artificial illumination for efficient photosynthesis. Plant-growth illumination systems require high photon flux in the spectral range corresponding with plant photosynthetic active radiation (PAR) (400 700 nm), high spatial uniformity to promote uniform growth, and high energy efficiency to minimize electricity usage. The proposed plant-growth system takes advantage of the highly diffuse reflective surfaces on the interior of a sphere, hemisphere, or other nearly enclosed structure that is coated with highly reflective materials. This type of surface and structure uniformly mixes discrete light sources to produce highly uniform illumination. Multiple reflections from within the domelike structures are exploited to obtain diffuse illumination, which promotes the efficient reuse of photons that have not yet been absorbed by plants. The highly reflective surfaces encourage only the plant tissue (placed inside the sphere or enclosure) to absorb the light. Discrete light sources, such as light emitting diodes (LEDs), are typically used because of their high efficiency, wavelength selection, and electronically dimmable properties. The light sources are arranged to minimize shadowing and to improve uniformity. Different wavelengths of LEDs (typically blue, green, and red) are used for photosynthesis. Wavelengths outside the PAR range can be added for plant diagnostics or for growth regulation

  1. 29 CFR 1926.56 - Illumination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Illumination. (a) General. Construction areas, ramps, runways, corridors, offices, shops, and storage areas... tunnel heading.) 10 General construction plant and shops (e.g., batch plants, screening plants, mechanical and electrical equipment rooms, carpenter shops, rigging lofts and active storerooms, barracks...

  2. Freeform LED lens for rectangularly prescribed illumination

    NASA Astrophysics Data System (ADS)

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

    2009-10-01

    Freeform lenses are playing a more and more important role in LED secondary optics design. In this study, based on the new light energy mapping relationship, edge ray principle, Snell's law and error control of surface construction, a modified discontinuous freeform lens design method was presented for rectangularly prescribed illumination, with the advantages of a flexible energy mapping relationship, accurate light irradiation control and easier to manufacture. A polymethyl methacrylate (PMMA) discontinuous freeform lens was designed as an example for LED tunnel illumination according to this method. The numerical simulation results demonstrated that the light pattern of the lens was in good agreement with the expected illumination performance when using a point source. Tolerance analyses were also conducted. An extended light source had little effect on the light output efficiency (LOE) of the lens but significantly decreased the effective illumination area. Installation errors had more effect on the uniformity and shape of the light pattern than the LOE of the lens. The tolerances of vertical, horizontal and rotational deviation of this lens were 0.4 mm, 0.4 mm and 2°, respectively.

  3. Multi-Perspective Illumination: A Case Study.

    ERIC Educational Resources Information Center

    Melton, R. F.; Zimmer, R. S.

    1987-01-01

    This description of an illuminative evaluation process as a qualitative research method focuses on a study of concerns about financial constraints in the British Open University. Interviews and open-ended discussions were used to encourage participation and input by a wide variety of individuals with differing perspectives on the problem. (LRW)

  4. Reflectance, illumination, and appearance in color constancy

    PubMed Central

    McCann, John J.; Parraman, Carinna; Rizzi, Alessandro

    2013-01-01

    We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor's reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation. PMID:24478738

  5. LED illuminator for a microdisplay projector

    NASA Astrophysics Data System (ADS)

    Magarill, Simon

    2012-10-01

    An illumination system for a microdisplay projector with a two-step imaging system is described here. In the first step, an imaging condenser creates an image of the LED at the color combiner entrance window. In the second step, we relay the image of the integrator exit window onto the micro-display. The illuminator demonstrates high collection efficiency, small footprint, and efficient mixing of light from RGB LEDs that provides required uniformity. A variety of approaches to collecting light emitted from LEDs of various types are compared, leading to the two-step design. A design example using a 0.55" diagonal DLP-based optical engine is presented with the following characteristics: Footprint: 3.9"x3.3"x2.0" (25.7 cubic inches) Light output: 338 white lumens Efficiency: 4.7 lm/watt

  6. Pulsed laser illumination of photovoltaic cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland A.; Jenkins, Phillip P.; Landis, Geoffrey A.

    1994-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. Both the radio-frequency (RF) and induction FEL provide FEL produce pulsed rather than continuous output. In this work we investigate cell response to pulsed laser light which simulates the RF FEL format. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced compared to constant illumination at the same wavelength. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments indicates that the RF FEL pulse format yields more efficient photovoltaic conversion than does an induction FEL pulse format.

  7. Pulsed laser illumination of photovoltaic cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland A.; Jenkins, Phillip P.; Landis, Geoffrey A.

    1995-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic receivers to provide remote power. Both the radio-frequency (RF) and induction FEL produce pulsed rather than continuous output. In this work we investigate cell response to pulsed laser light which simulates the RF FEL format. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced compared to constant illumination at the same wavelength. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments indicates that the RF FEL pulse format yields more efficient photovoltaic conversion than does an induction FEL format.

  8. Microscope illumination systems for 157 nm

    NASA Astrophysics Data System (ADS)

    Pesch, Alexander; Uhlendorf, Kristina; Deparnay, Arnaud; Erdmann, Lars; Kuschnerus, Peter; Engel, Thomas; Brunner, Robert

    2003-05-01

    The image quality of an inspection microscope depends strongly on the performance of the illumination system. Especially in the case of laser-based illumination it is necessary to transform the original beam profile into a homogeneous light spot with a flat top field distribution. Simultaneously, speckles caused by the coherence of the laser have to be reduced. Here we discuss different ways to homogenize the multi mode beam profile of a pulsed compact 157 nm excimer laser. A variety of setups, combining dynamic acting diffusers, microlens arrays and primary lenses were realized and characterized in several geometrical arrangements. The homogenizers were evaluated and characterized especially with respect to the statistical behavior on the integrated pulse number.

  9. Insulator Surface Flashover Due to UV Illumination

    SciTech Connect

    Javedani, J B; Houck, T L; Lahowe, D A; Vogtlin, G E; Goerz, D A

    2009-07-27

    The surface of an insulator under vacuum and under electrical charge will flashover when illuminated by a critical dose of ultra-violet (UV) radiation - depending on the insulator size and material, insulator cone angle, the applied voltage and insulator shot-history. A testbed comprised of an excimer laser (KrF, 248 nm, {approx}16 MW, 30 ns FWHM,), a vacuum chamber, and a negative polarity dc high voltage power supply ({le} -60 kV) were assembled to test 1.0 cm thick angled insulators for surface-flashover. Several candidate insulator materials, e.g. High Density Polyethylene (HDPE), Rexolite{reg_sign} 1400, Macor{trademark} and Mycalex, of varying cone angles were tested against UV illumination. Commercial energy meters were used to measure the UV fluence of the pulsed laser beam. In-house designed and fabricated capacitive probes (D-dots, >12 GHz bandwidth) were embedded in the anode electrode underneath the insulator to determine the time of UV arrival and time of flashover. Of the tested insulators, the +45 degree Rexolite insulator showed more resistance to UV for surface flashover; at UV fluence level of less than 13 mJ/cm{sup 2}, it was not possible to induce a flashover for up to -60 kV of DC potential across the insulator's surface. The probes also permitted the electrical charge on the insulator before and after flashover to be inferred. Photon to electron conversion efficiency for the surface of Rexolite insulator was determined from charge-balance equation. In order to understand the physical mechanism leading to flashover, we further experimented with the +45 degree Rexolite insulator by masking portions of the UV beam to illuminate only a section of the insulator surface; (1) the half nearest the cathode and subsequently, (2) the half nearest the anode. The critical UV fluence and time to flashover were measured and the results in each case were then compared with the base case of full-beam illumination. It was discovered that the time for the

  10. Compact laser illumination system for endoscopic interventions.

    PubMed

    Blase, Bastian

    2015-08-01

    External cold light sources as well as LEDs are commonly used for abdominal illumination in minimally invasive surgery. Still, both feature certain disadvantages. A new illumination system for endoscopes based on laser diodes is placed in the handle. No external light cables are needed. High conversion and coupling efficiencies and small package size allow for several diodes to be integrated, enabling color mixing and the adjustment of color temperatures. An optical module to collimate and combine the light is described. The heat to be dissipated is stored in a passive latent heat storage based on phase change materials surrounding the optical module. Thereby, operation time is considerably extended, as the handle's temperature is stabilized. To reduce the negative effect of coherent light on optical rough surfaces leading to patterns of spots, several devices for speckle reduction are developed and tested. By combining these components, an assembly of a powerful RGB laser light module for the integration in standard sized endoscopes is formed.

  11. Alternative Packaging for Back-Illuminated Imagers

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata

    2009-01-01

    An alternative scheme has been conceived for packaging of silicon-based back-illuminated, back-side-thinned complementary metal oxide/semiconductor (CMOS) and charge-coupled-device image-detector integrated circuits, including an associated fabrication process. This scheme and process are complementary to those described in "Making a Back-Illuminated Imager With Back-Side Connections" (NPO-42839), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 38. To avoid misunderstanding, it should be noted that in the terminology of imaging integrated circuits, "front side" or "back side" does not necessarily refer to the side that, during operation, faces toward or away from a source of light or other object to be imaged. Instead, "front side" signifies that side of a semiconductor substrate upon which the pixel pattern and the associated semiconductor devices and metal conductor lines are initially formed during fabrication, and "back side" signifies the opposite side. If the imager is of the type called "back-illuminated," then the back side is the one that faces an object to be imaged. Initially, a back-illuminated, back-side-thinned image-detector is fabricated with its back side bonded to a silicon handle wafer. At a subsequent stage of fabrication, the front side is bonded to a glass wafer (for mechanical support) and the silicon handle wafer is etched away to expose the back side. The frontside integrated circuitry includes metal input/output contact pads, which are rendered inaccessible by the bonding of the front side to the glass wafer. Hence, one of the main problems is to make the input/output contact pads accessible from the back side, which is ultimately to be the side accessible to the external world. The present combination of an alternative packaging scheme and associated fabrication process constitute a solution of the problem.

  12. Reinterpretation and improvement of Talbot array illuminators.

    PubMed

    Arrizón, V; Rojo-Velázquez, G

    2000-09-10

    We show that the transmittance of a finite Talbot array illuminator (TAI) can be expressed by the phase distribution of a pixelated lens, modulated by a discrete phase grating (G). Thus the TAI reconstruction field is given by the convolution of the grating's Fourier transform, with the point-spread function of the pixelated lens. On the basis of this approach we propose a method to improve the performance of a finite TAI by modifying the basic cell of the grating factor G.

  13. Moonbase night power by laser illumination

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1992-01-01

    Moonbase solar-power concepts must somehow address the energy storage problem posed by the 354-hour lunar night. Attention is presently given to the feasibility of laser-array illumination of a lunar base, using technology that is projected to be available in the near term. Beam-spreading due to atmospheric distortions could be reduced through the use of adaptive optics to compensate for atmospheric turbulence.

  14. Shape, Illumination, and Reflectance from Shading

    DTIC Science & Technology

    2013-05-29

    Shape, Illumination, and Reflectance from Shading Jonathan Barron Jitendra Malik Electrical Engineering and Computer Sciences University of...S) AND ADDRESS(ES) University of California at Berkeley, Electrical Engineering and Computer Sciences,Berkeley,CA,94720 8. PERFORMING ORGANIZATION...images [2], [3]. We will construct priors similar to those used � J.T. Barron and J. Malik are with the Department of Electrical Engi- neering and

  15. Illumination analysis of LAPAN's IR micro bolometer

    NASA Astrophysics Data System (ADS)

    Bustanul, A.; Irwan, P.; Andi M., T.

    2016-10-01

    We have since 2 years ago been doing a research in term of an IR Micrometer Bolometer which aims to fulfill our office, LAPAN, desire to put it as one of payloads into LAPAN's next micro satellite project, either at LAPAN A4 or at LAPAN A5. Due to the lack of experience on the subject, everything had been initiated by spectral radiance analysis adjusted by catastrophes sources in Indonesia, mainly wild fire (forest fire) and active volcano. Based on the result of the appropriate spectral radiance wavelength, 3.8 - 4 μm, and field of view (FOV), we, then, went through the further analysis, optical analysis. Focusing in illumination matter, the process was done by using Zemax software. Optical pass Interference and Stray light were two things that become our concern throughout the work. They could also be an evaluation of the performance optimization of illumination analysis of our optical design. The results, graphs, show that our design performance is close diffraction limited and the image blur of the geometrical produced by Lapan's IR Micro Bolometer lenses is in the pixel area range. Therefore, our optical design performance is relatively good and will produce image with high quality. In this paper, the Illumination analysis and process of LAPAN's Infra Red (IR) Micro Bolometer is presented.

  16. Optical mapping at increased illumination intensities

    NASA Astrophysics Data System (ADS)

    Kanaporis, Giedrius; Martišienė, Irma; Jurevičius, Jonas; Vosyliūtė, Rūta; Navalinskas, Antanas; Treinys, Rimantas; Matiukas, Arvydas; Pertsov, Arkady M.

    2012-09-01

    Voltage-sensitive fluorescent dyes have become a major tool in cardiac and neuro-electrophysiology. Achieving high signal-to-noise ratios requires increased illumination intensities, which may cause photobleaching and phototoxicity. The optimal range of illumination intensities varies for different dyes and must be evaluated individually. We evaluate two dyes: di-4-ANBDQBS (excitation 660 nm) and di-4-ANEPPS (excitation 532 nm) in the guinea pig heart. The light intensity varies from 0.1 to 5 mW/mm2, with the upper limit at 5 to 10 times above values reported in the literature. The duration of illumination was 60 s, which in guinea pigs corresponds to 300 beats at a normal heart rate. Within the identified duration and intensity range, neither dye shows significant photobleaching or detectable phototoxic effects. However, light absorption at higher intensities causes noticeable tissue heating, which affects the electrophysiological parameters. The most pronounced effect is a shortening of the action potential duration, which, in the case of 532-nm excitation, can reach ˜30%. At 660-nm excitation, the effect is ˜10%. These findings may have important implications for the design of optical mapping protocols in biomedical applications.

  17. Pulsed Laser Illumination of Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland; Jenkins, Philip; Landis, Geoffrey A.

    1994-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. The induction FEL and the radio-frequency (RF) FEL both produce pulsed rather than continuous output. In this work, we investigate cell response to pulsed laser light which simulates the RF FEL format, producing 50 ps pulses at a frequency of 78 MHz. A variety of Si, GaAs, CaSb and CdInSe2 (CIS) solar cells are tested at average incident powers between 4 mW/sq cm and 425 mW/sq cm. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced by using a pulsed laser source compared to constant illumination at the same wavelength. Because the pulse separation is less than or approximately equal to the minority carrier lifetime, the illumination conditions are effectively those of a continuous wave laser. The time dependence of the voltage and current response of the cells are also measured using a sampling oscilloscope equipped with a high frequency voltage probe and current transformer. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments shows that the RF FEL pulse format yields much more efficient photovoltaic conversion of light than does an induction FEL pulse format.

  18. 47 CFR 80.969 - Illumination of operating controls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... illuminate the operating controls at the principal operating position. (b) Instead of dial lights, a light from an electric lamp may be provided to illuminate the operating controls of the radiotelephone at...

  19. 47 CFR 80.969 - Illumination of operating controls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... illuminate the operating controls at the principal operating position. (b) Instead of dial lights, a light from an electric lamp may be provided to illuminate the operating controls of the radiotelephone at...

  20. Bessel light sheet structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Noshirvani Allahabadi, Golchehr

    Biomedical study researchers using animals to model disease and treatment need fast, deep, noninvasive, and inexpensive multi-channel imaging methods. Traditional fluorescence microscopy meets those criteria to an extent. Specifically, two-photon and confocal microscopy, the two most commonly used methods, are limited in penetration depth, cost, resolution, and field of view. In addition, two-photon microscopy has limited ability in multi-channel imaging. Light sheet microscopy, a fast developing 3D fluorescence imaging method, offers attractive advantages over traditional two-photon and confocal microscopy. Light sheet microscopy is much more applicable for in vivo 3D time-lapsed imaging, owing to its selective illumination of tissue layer, superior speed, low light exposure, high penetration depth, and low levels of photobleaching. However, standard light sheet microscopy using Gaussian beam excitation has two main disadvantages: 1) the field of view (FOV) of light sheet microscopy is limited by the depth of focus of the Gaussian beam. 2) Light-sheet images can be degraded by scattering, which limits the penetration of the excitation beam and blurs emission images in deep tissue layers. While two-sided sheet illumination, which doubles the field of view by illuminating the sample from opposite sides, offers a potential solution, the technique adds complexity and cost to the imaging system. We investigate a new technique to address these limitations: Bessel light sheet microscopy in combination with incoherent nonlinear Structured Illumination Microscopy (SIM). Results demonstrate that, at visible wavelengths, Bessel excitation penetrates up to 250 microns deep in the scattering media with single-side illumination. Bessel light sheet microscope achieves confocal level resolution at a lateral resolution of 0.3 micron and an axial resolution of 1 micron. Incoherent nonlinear SIM further reduces the diffused background in Bessel light sheet images, resulting in

  1. 21 CFR 886.1160 - Color vision plate illuminator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Color vision plate illuminator. 886.1160 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1160 Color vision plate illuminator. (a) Identification. A color vision plate illuminator is an AC-powered device that is a lamp...

  2. 21 CFR 886.1160 - Color vision plate illuminator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Color vision plate illuminator. 886.1160 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1160 Color vision plate illuminator. (a) Identification. A color vision plate illuminator is an AC-powered device that is a lamp...

  3. 21 CFR 886.1160 - Color vision plate illuminator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Color vision plate illuminator. 886.1160 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1160 Color vision plate illuminator. (a) Identification. A color vision plate illuminator is an AC-powered device that is a lamp...

  4. 21 CFR 886.1160 - Color vision plate illuminator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Color vision plate illuminator. 886.1160 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1160 Color vision plate illuminator. (a) Identification. A color vision plate illuminator is an AC-powered device that is a lamp...

  5. 21 CFR 886.1160 - Color vision plate illuminator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Color vision plate illuminator. 886.1160 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1160 Color vision plate illuminator. (a) Identification. A color vision plate illuminator is an AC-powered device that is a lamp...

  6. 30 CFR 56.17001 - Illumination of surface working areas.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Illumination of surface working areas. 56.17001... § 56.17001 Illumination of surface working areas. Illumination sufficient to provide safe working conditions shall be provided in and on all surface structures, paths, walkways, stairways, switch...

  7. 32 CFR 707.10 - Wake illumination light.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 5 2013-07-01 2013-07-01 false Wake illumination light. 707.10 Section 707.10... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.10 Wake illumination light. Naval vessels may display a white spot light located near the stern to illuminate the wake....

  8. 32 CFR 707.10 - Wake illumination light.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 5 2011-07-01 2011-07-01 false Wake illumination light. 707.10 Section 707.10... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.10 Wake illumination light. Naval vessels may display a white spot light located near the stern to illuminate the wake....

  9. 32 CFR 707.10 - Wake illumination light.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 5 2012-07-01 2012-07-01 false Wake illumination light. 707.10 Section 707.10... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.10 Wake illumination light. Naval vessels may display a white spot light located near the stern to illuminate the wake....

  10. 30 CFR 75.1719-1 - Illumination in working places.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... working place, the areas within a miner's normal field of vision which shall be illuminated in the working... are operated, the areas which shall be illuminated shall be as follows: (i) The face, and (ii) The... equipment is operated to load material, the areas which shall be illuminated shall be as follows: (i)...

  11. 30 CFR 75.1719-1 - Illumination in working places.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... working place, the areas within a miner's normal field of vision which shall be illuminated in the working... are operated, the areas which shall be illuminated shall be as follows: (i) The face, and (ii) The... equipment is operated to load material, the areas which shall be illuminated shall be as follows: (i)...

  12. 32 CFR 707.10 - Wake illumination light.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Wake illumination light. 707.10 Section 707.10... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.10 Wake illumination light. Naval vessels may display a white spot light located near the stern to illuminate the wake....

  13. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  14. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  15. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  16. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  17. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  18. 32 CFR 707.10 - Wake illumination light.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 5 2014-07-01 2014-07-01 false Wake illumination light. 707.10 Section 707.10... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.10 Wake illumination light. Naval vessels may display a white spot light located near the stern to illuminate the wake....

  19. Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons

    PubMed Central

    Bosse, Jens B.; Tanneti, Nikhila S.; Hogue, Ian B.; Enquist, Lynn W.

    2015-01-01

    Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs), however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution. PMID:26600461

  20. Ultra Deep Wave Equation Imaging and Illumination

    SciTech Connect

    Alexander M. Popovici; Sergey Fomel; Paul Sava; Sean Crawley; Yining Li; Cristian Lupascu

    2006-09-30

    In this project we developed and tested a novel technology, designed to enhance seismic resolution and imaging of ultra-deep complex geologic structures by using state-of-the-art wave-equation depth migration and wave-equation velocity model building technology for deeper data penetration and recovery, steeper dip and ultra-deep structure imaging, accurate velocity estimation for imaging and pore pressure prediction and accurate illumination and amplitude processing for extending the AVO prediction window. Ultra-deep wave-equation imaging provides greater resolution and accuracy under complex geologic structures where energy multipathing occurs, than what can be accomplished today with standard imaging technology. The objective of the research effort was to examine the feasibility of imaging ultra-deep structures onshore and offshore, by using (1) wave-equation migration, (2) angle-gathers velocity model building, and (3) wave-equation illumination and amplitude compensation. The effort consisted of answering critical technical questions that determine the feasibility of the proposed methodology, testing the theory on synthetic data, and finally applying the technology for imaging ultra-deep real data. Some of the questions answered by this research addressed: (1) the handling of true amplitudes in the downward continuation and imaging algorithm and the preservation of the amplitude with offset or amplitude with angle information required for AVO studies, (2) the effect of several imaging conditions on amplitudes, (3) non-elastic attenuation and approaches for recovering the amplitude and frequency, (4) the effect of aperture and illumination on imaging steep dips and on discriminating the velocities in the ultra-deep structures. All these effects were incorporated in the final imaging step of a real data set acquired specifically to address ultra-deep imaging issues, with large offsets (12,500 m) and long recording time (20 s).

  1. Image Correlation Microscopy for Uniform Illumination

    PubMed Central

    Gaborski, Thomas R.; Sealander, Michael N.; Ehrenberg, Morton; Waugh, Richard E.; McGrath, James L.

    2011-01-01

    Image cross-correlation microscopy (ICM) is a technique that quantifies the motion of fluorescent features in an image by measuring the temporal autocorrelation function decay in a time-lapse image sequence. ICM has traditionally employed laser-scanning microscopes because the technique emerged as an extension of laser-based fluorescence correlation spectroscopy (FCS). In this work, we show that image correlation can also be used to measure fluorescence dynamics in uniform illumination or wide-field imaging systems and we call our new approach uniform illumination image correlation microscopy (UI-ICM). Wide-field microscopy is not only a simpler, less expensive imaging modality, but it offers the capability of greater temporal resolution over laser-scanning systems. In traditional laser-scanning ICM, lateral mobility is calculated from the temporal de-correlation of an image, where the characteristic length is the illuminating laser beam width. In wide-field microscopy, the diffusion length is defined by the feature size using the spatial autocorrelation function (SACF). Correlation function decay in time occurs as an object diffuses from its original position. We show that theoretical and simulated comparisons between Gaussian and uniform features indicate the temporal autocorrelation function (TACF) depends strongly on particle size and not particle shape. In this report, we establish the relationships between the SACF feature size, TACF characteristic time and the diffusion coefficient for UI-ICM using analytical, Monte-Carlo and experimental validation with particle tracking algorithms. Additionally, we demonstrate UI-ICM analysis of adhesion molecule domain aggregation and diffusion on the surface of human neutrophils. PMID:20055917

  2. Organic light emitting devices for illumination

    SciTech Connect

    Hack, Michael; Lu, Min-Hao Michael; Weaver, Michael S.

    2010-02-16

    An organic light emitting device is provided. The device has a plurality of regions, each region having an organic emissive layer adapted to emit a different spectrum of light. The regions in combination emit light suitable for illumination purposes. The area of each region may be selected such that the device is more efficient that an otherwise equivalent device having regions of equal size. The regions may have an aspect ratio of at least about four. All parts of any given region may be driven at the same current.

  3. Illuminating Rationale and Uses for Light Therapy

    PubMed Central

    Shirani, Afshin; St. Louis, Erik K.

    2009-01-01

    Light therapy is increasingly applied in a variety of sleep medicine and psychiatric conditions including circadian rhythm sleep disorders, seasonal affective disorder, and dementia. This article reviews the neural underpinnings of circadian neurobiology crucial for understanding the influence of light therapy on brain function, common mood and sleep disorders in which light therapy may be effectively used, and applications of light therapy in clinical practice. Citation: Shirani A; St. Louis EK. Illuminating rationale and uses for light therapy. J Clin Sleep Med 2009;5(2):155-163. PMID:19968050

  4. Surface sampling techniques using ultraviolet illumination

    NASA Astrophysics Data System (ADS)

    Smith, E. M.; Aronson, J. R.; Cornish, R. M.; Goodwin, B. E.; Simon, I.

    1984-11-01

    In laboratory and preliminary field tests, a system that uses photography in the presence of a 254 nm UV illumination source has been shown useful for detection of explosives residues on surfaces. Analytes (TNT, 2, 4-DNT, 2, 6-DNT, Tetryl, RDX and DPA) can be detected at 10 to 20 microgram/sq cm on concrete, transite or stainless steel. The method was not successful for wood or brick surfaces or for the analyte PETN. An alternative thermal image radiometric method of detection was unsuccessful.

  5. Thermoelectric Nanowire Arrays Response to Illumination

    NASA Astrophysics Data System (ADS)

    Huber, Tito; Scott, Reum; Johnson, Scott; Brower, Tina; Nikolaeva, Albina; Konopko, Leonid

    Bismuth nanowire arrays configured on devices where they are capped with a transparent indium tin oxide electrode generate electric power when exposed to light. The arrays feature poor optical reflectivity and, possibly, light trapping. We show experimental results that indicate that the arrays respond to illumination owing to the thermoelectric conversion of heat absorbed at the surface. The unique features of the energy pathway are manifested through a strong temporal and photon wavelength dependence of the photoresponse. Energy conversion in thermoelectrics with light trapping surfaces is a path to fast infrared light detection and across-the-spectrum solar energy harvesting.

  6. Methods for describing illumination colour uniformities

    NASA Astrophysics Data System (ADS)

    Rotscholl, Ingo; Trampert, Klaus; Herrmann, Franziska; Neumann, Cornelius

    2015-02-01

    Optimizing angular or spatial colour homogeneity has become an important task in many general lighting applications and first requires a valid description of illumination colour homogeneity. We analyse different frequently used methods to describe colour distributions in theory and with measurement data. It is described why information about chromaticity coordinates, correlated colour temperature and global chromaticity coordinate distances are not sufficient for describing colour homogeneity perception of light distributions. We present local chromaticity coordinate distances as expandable and easy implementable method for describing colour homogeneity distributions that is adaptable to the field of view by only one intuitive, physiological meaningful parameter.

  7. Development of flying spot illumination system for stage lighting

    NASA Astrophysics Data System (ADS)

    Asakawa, Hisashi; Ishii, Katsunori; Koshiro, Hikari; Baba, Junko; Wakaki, Moriaki

    2014-02-01

    The system to control the area of illumination is important for the luminaires used for stages and TV studios. Presently the methods to change the distance between a lamp and lenses, or to use a zooming projection of the aperture illuminated by the lamp are used to control the area. However, these methods require many optical components or mechanical components. Moreover, the energy of the light source is partially consumed by the absorption of the shutter on adjusting the illumination area. On the other hand, the control of the illuminance over the illuminated area is not possible by the methods. In this study, we developed the lighting system which enables to control both the illuminated area and the illuminance distribution within the area by scanning the beam from a LED array light source. The area of illumination was expanded along one dimension by scanning the LED beam using a rotating polygon mirror. The selection of the illuminated width and the control of the illuminance distribution were achieved by synchronizing the pulse width modulation (PWM) control of the LED with the rotation of the mirror using a time sharing control. As a result, various illuminance distributions can be realized at real time by using software control for the luminaire. The developed system has the merits of compact and high efficiency.

  8. Can illumination estimates provide the basis for color constancy?

    PubMed

    Granzier, Jeroen J M; Brenner, Eli; Smeets, Jeroen B J

    2009-03-24

    Objects hardly appear to change color when the spectral distribution of the illumination changes: a phenomenon known as color constancy. Color constancy could either be achieved by relying on properties that are insensitive to changes in the illumination (such as spatial color contrast) or by compensating for the estimated chromaticity of the illuminant. We examined whether subjects can judge the illuminant's color well enough to account for their own color constancy. We found that subjects were very poor at judging the color of a lamp from the light reflected by the scene it illuminated. They were much better at judging the color of a surface within the scene. We conclude that color constancy must be achieved by relying on relationships that are insensitive to the illumination rather than by explicitly judging the color of the illumination.

  9. Effects of illuminants and illumination time on lettuce growth, yield and nutritional quality in a controlled environment

    NASA Astrophysics Data System (ADS)

    Shen, Y. Z.; Guo, S. S.; Ai, W. D.; Tang, Y. K.

    2014-07-01

    Effects of illuminants and illumination time on the growth of lettuce were researched. Red-blue light-emitting diodes (LEDs, 90% red light +10% blue light) and white light fluorescent (WF) lamps were compared as the illuminants for plant cultivation. Under each type of illuminant, lettuce was grown at 4 illumination times: 12 h, 16 h, 20 h and 24 h, with the same light intensity of 600 μmolm-2s-1. The leaf net photosynthetic rate (Pn) under the two illuminants was comparable but the shape of lettuce was obviously affected by the illuminant. The WF lamps produced more compact plant, while red-blue LED resulted in less but longer leaves. However, the total leaf area was not significantly affected by the illuminant. The red-blue LED produced nearly same aboveground biomass with far less energy consumption relative to WF lamps. The underground biomass was lowered under red-blue LED in comparison with WF lamps. Red-blue LED could improve the nutritional quality of lettuce by increasing the concentration of soluble sugar and vitamin C (VC) and reducing the concentration of nitrate. Under each type of illuminant, longer illumination time resulted in higher Pn, more leaves and larger leaf area. The total chlorophyll concentration increased while the concentration ratio of chlorophyll a/b decreased with the extension of illumination time. Illumination time had highly significant positive correlation with biomass. Moreover, when total daily light input was kept the same, longer illumination time increased the biomass significantly as well. In addition, longer illumination time increased the concentration of crude fiber, soluble sugar and VC and reduced the concentration of nitrate. In summary, red-blue LEDs and 24 h illumination time were demonstrated to be more suitable for lettuce cultivation in the controlled environment.

  10. Construction of an instant structured illumination microscope

    PubMed Central

    Curd, Alistair; Cleasby, Alexa; Makowska, Katarzyna; York, Andrew; Shroff, Hari; Peckham, Michelle

    2015-01-01

    A challenge in biological imaging is to capture high-resolution images at fast frame rates in live cells. The “instant structured illumination microscope” (iSIM) is a system designed for this purpose. Similarly to standard structured illumination microscopy (SIM), an iSIM provides a twofold improvement over widefield microscopy, in x, y and z, but also allows much faster image acquisition, with real-time display of super-resolution images. The assembly of an iSIM is reasonably complex, involving the combination and alignment of many optical components, including three micro-optics arrays (two lenslet arrays and an array of pinholes, all with a pitch of 222 μm) and a double-sided scanning mirror. In addition, a number of electronic components must be correctly controlled. Construction of the system is therefore not trivial, but is highly desirable, particularly for live-cell imaging. We report, and provide instructions for, the construction of an iSIM, including minor modifications to a previous design in both hardware and software. The final instrument allows us to rapidly acquire fluorescence images at rates faster than 100 fps, with approximately twofold improvement in resolution in both x–y and z; sub-diffractive biological features have an apparent size (full width at half maximum) of 145 nm (lateral) and 320 nm (axial), using a 1.49 NA objective and 488 nm excitation. PMID:26210400

  11. Design and analysis of illumination systems

    NASA Astrophysics Data System (ADS)

    Zoechling, Guenter

    1991-01-01

    Illuminance at a detector is calculated by means of raytracing. A method of synthesis already known from related fields - is demonstrated: the Edge Ray Principle. 1. 1 Concepts of photometry 1. ANALYSIS We have to recall the basic physical concepts of photometry namely luminance light intensity light flux and illuminance [21 The definition of a Lambertian Source is given here again due to its fundamental importance: we call a radiating surface a Lambertian Source its luminance is independent of surface coordinates and viewing angle. An equivalent formulation is: the source obeys ''Lamberts cosine law of intensity'' for any surface element dA and any angle B dl L * cos B * dA (1) L luminance dA surface element at source I intensity B angle between surface normal and viewing direction The Lambertian Source has several interesting attributes for instance that we cannot judge its position or shape by just looking at it. A more precise formulation of this phenomenon can be stated as following: 1. 2 Pseudo luminance of the hole Let D be some area on a detector H be a hole in an opaque screen (both not necessarily small) and Si and S2 be lambertian radiating surfaces (alternatively existing) then the following theorem holds: SPIE Vol. 1354 International Lens Design Conference (1990) / 617 y D (p y H (p Fig. i

  12. Laser scattering by transcranial rat brain illumination

    NASA Astrophysics Data System (ADS)

    Sousa, Marcelo V. P.; Prates, Renato; Kato, Ilka T.; Sabino, Caetano P.; Suzuki, Luis C.; Ribeiro, Martha S.; Yoshimura, Elisabeth M.

    2012-06-01

    Due to the great number of applications of Low-Level-Laser-Therapy (LLLT) in Central Nervous System (CNS), the study of light penetration through skull and distribution in the brain becomes extremely important. The aim is to analyze the possibility of precise illumination of deep regions of the rat brain, measure the penetration and distribution of red (λ = 660 nm) and Near Infra-Red (NIR) (λ = 808 nm) diode laser light and compare optical properties of brain structures. The head of the animal (Rattus Novergicus) was epilated and divided by a sagittal cut, 2.3 mm away from mid plane. This section of rat's head was illuminated with red and NIR lasers in points above three anatomical structures: hippocampus, cerebellum and frontal cortex. A high resolution camera, perpendicularly positioned, was used to obtain images of the brain structures. Profiles of scattered intensities in the laser direction were obtained from the images. There is a peak in the scattered light profile corresponding to the skin layer. The bone layer gives rise to a valley in the profile indicating low scattering coefficient, or frontal scattering. Another peak in the region related to the brain is an indication of high scattering coefficient (μs) for this tissue. This work corroborates the use of transcranial LLLT in studies with rats which are subjected to models of CNS diseases. The outcomes of this study point to the possibility of transcranial LLLT in humans for a large number of diseases.

  13. Construction of an instant structured illumination microscope.

    PubMed

    Curd, Alistair; Cleasby, Alexa; Makowska, Katarzyna; York, Andrew; Shroff, Hari; Peckham, Michelle

    2015-10-15

    A challenge in biological imaging is to capture high-resolution images at fast frame rates in live cells. The "instant structured illumination microscope" (iSIM) is a system designed for this purpose. Similarly to standard structured illumination microscopy (SIM), an iSIM provides a twofold improvement over widefield microscopy, in x, y and z, but also allows much faster image acquisition, with real-time display of super-resolution images. The assembly of an iSIM is reasonably complex, involving the combination and alignment of many optical components, including three micro-optics arrays (two lenslet arrays and an array of pinholes, all with a pitch of 222 μm) and a double-sided scanning mirror. In addition, a number of electronic components must be correctly controlled. Construction of the system is therefore not trivial, but is highly desirable, particularly for live-cell imaging. We report, and provide instructions for, the construction of an iSIM, including minor modifications to a previous design in both hardware and software. The final instrument allows us to rapidly acquire fluorescence images at rates faster than 100 fps, with approximately twofold improvement in resolution in both x-y and z; sub-diffractive biological features have an apparent size (full width at half maximum) of 145 nm (lateral) and 320 nm (axial), using a 1.49 NA objective and 488 nm excitation.

  14. Robust Face Image Matching under Illumination Variations

    NASA Astrophysics Data System (ADS)

    Yang, Chyuan-Huei Thomas; Lai, Shang-Hong; Chang, Long-Wen

    2004-12-01

    Face image matching is an essential step for face recognition and face verification. It is difficult to achieve robust face matching under various image acquisition conditions. In this paper, a novel face image matching algorithm robust against illumination variations is proposed. The proposed image matching algorithm is motivated by the characteristics of high image gradient along the face contours. We define a new consistency measure as the inner product between two normalized gradient vectors at the corresponding locations in two images. The normalized gradient is obtained by dividing the computed gradient vector by the corresponding locally maximal gradient magnitude. Then we compute the average consistency measures for all pairs of the corresponding face contour pixels to be the robust matching measure between two face images. To alleviate the problem due to shadow and intensity saturation, we introduce an intensity weighting function for each individual consistency measure to form a weighted average of the consistency measure. This robust consistency measure is further extended to integrate multiple face images of the same person captured under different illumination conditions, thus making our robust face matching algorithm. Experimental results of applying the proposed face image matching algorithm on some well-known face datasets are given in comparison with some existing face recognition methods. The results show that the proposed algorithm consistently outperforms other methods and achieves higher than 93% recognition rate with three reference images for different datasets under different lighting conditions.

  15. Modeling polarized illumination for OPC/RET

    NASA Astrophysics Data System (ADS)

    Song, Hua; Zhang, Qiaolin; Shiely, James

    2007-10-01

    Recent research has shown that properly polarized light source enhances image contrast in photolithography for manufacturing integrated circuit (IC) devices, thus improves the effectiveness of optical proximity correction (OPC) and other resolution enhancement techniques (RET). However, current OPC/RET modeling software can only model the light source polarization of simple types, such as TE, TM, X, Y, or sector polarization with relatively simple configuration. Realistic polarized light used in scanners is more complex than the aforementioned simple ones. As a result, simulation accuracy and quality of the OPC result will be compromised by the simplification of the light source polarization modeling in the traditional approach. With ever shrinking CD error budget in the manufacturing of IC's at advanced technology nodes, more accurate and comprehensive light source modeling for lithography simulations and OPC/RET is needed. In this paper, we present a modeling framework that takes arbitrarily polarized light source. Based on polarization state vector descriptions of the light source, it unifies optical simulations of unpolarized, partially polarized, and completely polarized illuminations. We built this framework into Synopsys' OPC modeling tool ProGen. Combined with ProGen's existing capability to handle vectorial aberration by the projection lens, large angle effects due to high NA, and thin film effects, this framework represents a general vectorial model for optical imaging with the state-of-the-art scanners. Numerical experiments were performed to study CD impact of various illumination polarization modeling schemes in the context of OPC/RET.

  16. Backlight illumination design using constant extinction

    NASA Astrophysics Data System (ADS)

    Baumgart, Jörg

    2013-08-01

    Light guiding backlights are a good solution to attain ambient or display illuminations. Generally, they are attained using intended macroscopic defects (dots). Their size, shape and density are designed using ray tracing software. Smaller defects have the fascinating feature that they may not be perceived by the eye. Such a light guide will therefore look transparent and undisturbed. However, such microscopic or even nanoscaled defects are well beyond the limitations of geometrical optics and therefore need other approaches for their design. An interesting alternative to surface defects are particles inside the material or a well-defined surface roughness. In contrast to a defect structure, particle densities or surface roughness cannot be changed without difficulty. These may, however, be much more easily manufactured. In this paper, a simple analytical method for the design of such light guides will be presented. This method is compared to the results of commercial software and will be used to design a homogeneous illumination adopting constant particle density inside the material.

  17. Surface color perception and equivalent illumination models.

    PubMed

    Brainard, David H; Maloney, Laurence T

    2011-05-02

    Vision provides information about the properties and identity of objects. The ease with which we perceive object properties belies the difficulty of the underlying information-processing task. In the case of object color, retinal information about object reflectance is confounded with information about the illumination as well as about the object's shape and pose. There is no obvious rule that allows transformation of the retinal image to a color representation that depends primarily on object surface reflectance. Under many circumstances, however, object color appearance is remarkably stable across scenes in which the object is viewed. Here, we review a line of experiments and theory that aim to understand how the visual system stabilizes object color appearance. Our emphasis is on models derived from explicit analysis of the computational problem of estimating the physical properties of illuminants and surfaces from the retinal image, and experiments that test these models. We argue that this approach has considerable promise for allowing generalization from simplified laboratory experiments to richer scenes that more closely approximate natural viewing. We discuss the relation between the work we review and other theoretical approaches available in the literature.

  18. Illuminating Chaucer through Poetry, Manuscript Illuminations, and a Critical Rap Album

    ERIC Educational Resources Information Center

    Lynch, Tom Liam

    2007-01-01

    Drawing connections between Chaucer, Eminem, and social issues, New York City high school teacher Tom Liam Lynch helped students become familiar with "The Canterbury Tales." Students wrote poems of rhymed couplets about today's social and political issues, created illuminated manuscripts, and recorded a rap CD. A book and album were…

  19. Effects of artificial illumination on the nocturnal foraging of waders

    NASA Astrophysics Data System (ADS)

    Santos, Carlos D.; Miranda, Ana C.; Granadeiro, José P.; Lourenço, Pedro M.; Saraiva, Sara; Palmeirim, Jorge M.

    2010-03-01

    Large areas of natural and semi-natural habitats are exposed to artificial illumination from adjacent urban areas and roads. Estuarine and coastal wetlands are particularly exposed to such illumination because shorelines often are heavily utilized by man. However, the impact of artificial illumination on the waders that forage in these highly productive habitats is virtually unknown. We evaluated the effects of artificial illumination on the nocturnal habitat selection and foraging behaviour of six wader species with different feeding strategies: three visual foragers, two species that alternate visual and tactile strategies (mixed foragers), and one tactile forager. We quantified the number of birds and their foraging behaviour at sites affected and not affected by streetlights, and also before and after illuminating experimental sites. Areas illuminated by streetlights were used more during the night by visual foragers, and to a lesser extent by mixed foragers, than non-illuminated areas. Visual foragers increased their foraging effort in illuminated areas, and mixed foragers changed to more efficient visual foraging strategies. These behavioural shifts improved prey intake rate by an average of 83% in visual and mixed foragers. We have showed that artificial illumination has a positive effect on the nocturnal foraging of waders, but on the other hand may draw them to degraded areas close to urban centres, and potentially raises their exposure to predators. Our findings suggest that artificial illumination is worth investigation as a tool in the management of intertidal habitats for waders.

  20. Material-illumination ambiguities and the perception of solid objects.

    PubMed

    Pont, Sylvia C; te Pas, Susan F

    2006-01-01

    The appearance of objects depends on their material, shape, and on the illumination conditions. Conversely, object appearance provides us with cues about the illumination and the material. This so-called inverse problem is basically underdetermined and therefore we expect that material and illumination perception are confounded. To gain insight into the relevant mechanisms, we rendered a set of artificial spheres for vastly different canonical light fields and reflectance functions. We used four physics-based bidirectional reflectance distribution functions (BRDFs) representing glossy, pitted, velvety, and matte material. The six illumination conditions were collimated illumination from four directions, hemispherical diffuse illumination, and fully diffuse (Ganzfeld) illumination. In three sub-experiments we presented pairs of stimuli and asked human observers to judge whether the material was the same, whether the illumination was the same, and for a subset in which either the illumination or the material was the same to judge which of the two was constant. We found that observers made many errors in all sub-experiments. In experiment 2 the illumination direction was chosen at random. Using an interactive interface, we asked human observers to match the illumination direction of a sphere of one of the four materials with that of a Lambertian sphere. We found systematical material-dependent deviations from veridical performance. Theoretical analysis of the radiance patterns suggests that judgments were based mainly on the position of the shadow edge. In conclusion, we found no evidence for 'material constancy' for perception of smooth rendered spheres despite vast quantitative and qualitative differences in illumination and in BRDF between the stimuli. Although human observers demonstrated some 'illumination constancy', they made systematic errors depending on the material reflectance, suggesting that they used mainly the location of the shadow edge. Our results

  1. Infrared Beam Induced Contrast With Double Illumination

    NASA Astrophysics Data System (ADS)

    Castaldini, A.; Cavallini, A.

    1988-07-01

    Over the last few years scanning optical microscopy (SOM) has been largely developed as a tool to explore the physical properties of materials. In particular the optical beam induced current (OBIC) mode of the SOM has been used to map the electronic properties of semiconducting devices. A new type of scanning microscopy method, as well as some results obtained by it, will be reported in this paper. Though similar, to a certain extent, to the standard scanning optical microscopy, this new investigation technique, from now on refered to as infrared beam induced contrast (IRBIC), differs from it in substance. The chopped light from a quartz halogen lamp is focused by a conventional microscope rearranged on the specimen surface, and a pin-hole is positioned so as to reduce the probe size (not the resolving power) to 1.5um. The resulting beam power density is of the order of 1mW*cm-2. Such a low power density presents some disadvantages in comparison with the traditional laser sources, but, on the other hand, it allows a very high sensitivity in the investigation of the defect electrical activity. With this experimental set-up the specimen front surface is probed with band-gap radiation. Its back surface is illuminated by continuous light in the infrared, coming through a monochromator from a glow-bar. The radiation wavelength can be selected continuously so as the photon energy ranges over the whole valence-to-conduction energy gap. When the specimen is probed, the photoinduced carriers are separated by the built-in field due to the depletion zone of a p-n junction or a Schottky barrier, and the photocurrent is amplified by the lock-in technique. The application of a back-surface radiation of less than the band-gap energy modifies, in some way, the photoconductive response to the band-gap probe since the secondary illumination changes the occupancy of the traps in the forbidden gap active in the photoconductive process. This phenomenon, known as "quenching" of

  2. Junction-side illuminated silicon detector arrays

    DOEpatents

    Iwanczyk, Jan S.; Patt, Bradley E.; Tull, Carolyn

    2004-03-30

    A junction-side illuminated detector array of pixelated detectors is constructed on a silicon wafer. A junction contact on the front-side may cover the whole detector array, and may be used as an entrance window for light, x-ray, gamma ray and/or other particles. The back-side has an array of individual ohmic contact pixels. Each of the ohmic contact pixels on the back-side may be surrounded by a grid or a ring of junction separation implants. Effective pixel size may be changed by separately biasing different sections of the grid. A scintillator may be coupled directly to the entrance window while readout electronics may be coupled directly to the ohmic contact pixels. The detector array may be used as a radiation hardened detector for high-energy physics research or as avalanche imaging arrays.

  3. Pathway illuminated: visualizing protein kinase C signaling.

    PubMed

    Violin, Jonathan D; Newton, Alexandra C

    2003-12-01

    Protein kinase C has been at the center of cell signaling since the discovery 25 years ago that it transduces signals that promote phospholipid hydrolysis. In recent years, the use of genetically encoded fluorescent reporters has enabled studies of the regulation of protein kinase C signaling in living cells. Advances in imaging techniques have unveiled unprecedented detail of the signal processing mechanics of protein kinase C, from the second messengers calcium and diacylglycerol that regulate protein kinase C activity, to the locations and kinetics of different protein kinase C isozymes, to the spatial and temporal dynamics of substrate phosphorylation by this key enzyme. This review discusses how fluorescence imaging studies have illuminated the fidelity with which protein kinase C transduces rapidly changing extracellular information into intracellular phosphorylation signals.

  4. Illumination for Worm Tracking and Behavioral Imaging

    PubMed Central

    Yemini, Eviatar; Kerr, Rex A.; Schafer, William R.

    2016-01-01

    Neurobiological research in genetically tractable organisms relies heavily on robust assays for behavioral phenotypes. The simple body plan of the nematode Caenorhabditis elegans makes it particularly amenable to the use of automated microscopy and image analysis to describe behavioral patterns quantitatively. This protocol provides an approach for obtaining uniform illumination during worm tracking. Good lighting can be more of an art than a science. Once the system is set up, it will be necessary to play with it, testing the results after each adjustment to ensure that the analysis software is able to clearly identify the worm and its boundaries. Although the protocol was developed for use in a single-worm tracker, it addresses factors important for the generation of reproducible, standardized images in all systems. PMID:22135668

  5. Achromatic illumination system for small targets

    DOEpatents

    Sigler, Robert D.

    1979-01-01

    A pair of light beams is directed to provide illumination that is substantially uniform from all directions on a small target by a system comprising a pair of corrector windows, a pair of planar reflecting surfaces, a pair of paraboloidal mirrors and a reflecting mirror cavity. The components are arranged so that each of the beams passes through a corrector and is reflected from the planar surface to the paraboloidal mirror, from which it is focused through a hole in the planar surface to the interior of the cavity. The surface of the interior portion of the cavity is shaped to reflect the focused beam three times before the focused reflected beam strikes the target.

  6. Adaptive multispectral illumination for retinal microsurgery.

    PubMed

    Sznitman, Raphael; Rother, Diego; Handa, Jim; Gehlbach, Peter; Hager, Gregory D; Taylor, Russell

    2010-01-01

    It has been shown that excessive white light exposure during retinal microsurgery can induce retinal damage. To address this problem, one can illuminate the retina with a device that alternates between white, and less damaging limited-spectrum light. The surgeon is then presented with a fully colored video by recoloring the limited-spectrum light frames, using information from the white-light frames. To obtain accurately colored images, while reducing phototoxicity, we have developed a novel algorithm that monitors the quality of the recolored images and determines when white light may be substituted by limited-spectrum light. We show qualitatively and quantitatively that our system can provide reliable images using a significantly smaller light dose as compared to other state-of-the-art coloring schemes.

  7. Implementation of phase-shift focus monitor with modified illumination

    NASA Astrophysics Data System (ADS)

    Nakao, Shuji; Maejima, Shinroku; Ueno, Atsushi; Yamashita, Shigenori; Miyazaki, Junji; Tokui, Akira; Tsujita, Kouichirou; Arimoto, Ichiriou

    2002-07-01

    For the convenience of practical use of phase shift focus monitor (PSFM), which has been developed by T. Brunner, imaging characteristics of PSFM are investigated under modified illumination by optical image calculations and printing experiments. Although the mechanism of pattern shift with focus offset under modified illumination is different from that for conventional high coherent illumination, sufficient sensitivity for precise focus monitoring is predicted by optical image calculations. Also, it is revealed that reduction of NA, i.e., localizing illumination at the peripheral part of pupil is effective to obtain higher sensitivity. By experiments, predicted characteristics are observed and similar sensitivity to that in conventional high coherent illumination is confirmed both for annular and quadrupole illuminations.

  8. Multiple Illuminant Colour Estimation via Statistical Inference on Factor Graphs.

    PubMed

    Mutimbu, Lawrence; Robles-Kelly, Antonio

    2016-08-31

    This paper presents a method to recover a spatially varying illuminant colour estimate from scenes lit by multiple light sources. Starting with the image formation process, we formulate the illuminant recovery problem in a statistically datadriven setting. To do this, we use a factor graph defined across the scale space of the input image. In the graph, we utilise a set of illuminant prototypes computed using a data driven approach. As a result, our method delivers a pixelwise illuminant colour estimate being devoid of libraries or user input. The use of a factor graph also allows for the illuminant estimates to be recovered making use of a maximum a posteriori (MAP) inference process. Moreover, we compute the probability marginals by performing a Delaunay triangulation on our factor graph. We illustrate the utility of our method for pixelwise illuminant colour recovery on widely available datasets and compare against a number of alternatives. We also show sample colour correction results on real-world images.

  9. Laser agile illumination for object tracking and classification - Feasibility study

    NASA Technical Reports Server (NTRS)

    Scholl, Marija S.; Vanzyl, Jakob J.; Meinel, Aden B.; Meinel, Marjorie P.; Scholl, James W.

    1988-01-01

    The 'agile illumination' concept for discrimination between ICBM warheads and decoys involves a two-aperture illumination with coherent light, diffraction of light by propagation, and a resulting interference pattern on the object surface. A scanning two-beam interference pattern illuminates one object at a time; depending on the shape, momentum, spinning, and tumbling characteristics of the interrogated object, different temporal signals will be obtained for different classes of objects.

  10. Energy efficient LED layout optimization for near-uniform illumination

    NASA Astrophysics Data System (ADS)

    Ali, Ramy E.; Elgala, Hany

    2016-09-01

    In this paper, we consider the problem of designing energy efficient light emitting diodes (LEDs) layout while satisfying the illumination constraints. Towards this objective, we present a simple approach to the illumination design problem based on the concept of the virtual LED. We formulate a constrained optimization problem for minimizing the power consumption while maintaining a near-uniform illumination throughout the room. By solving the resulting constrained linear program, we obtain the number of required LEDs and the optimal output luminous intensities that achieve the desired illumination constraints.

  11. Fundamental study of illumination transformation for color vision deficiencies

    NASA Astrophysics Data System (ADS)

    Bao, Shi; Tanaka, Go; Tajima, Johji

    2015-02-01

    An object's color depends on its reflectance and illumination, and dichromats cannot distinguish specific color pairs. It is considered that there is an appropriate illumination under which a dichromat can distinguish confusing color pairs. In this study, a fundamental investigation of an illumination transformation to assist dichromats is carried out. Because the appropriate illumination depends on the object, we propose a search algorithm for the optimum light source spectrum for an object. In experiments, the effectiveness of the proposed method is examined using digital images and an sRGB display.

  12. High Efficiency, Illumination Quality OLEDs for Lighting

    SciTech Connect

    Joseph Shiang; James Cella; Kelly Chichak; Anil Duggal; Kevin Janora; Chris Heller; Gautam Parthasarathy; Jeffery Youmans; Joseph Shiang

    2008-03-31

    The goal of the program was to demonstrate a 45 lumen per watt white light device based upon the use of multiple emission colors through the use of solution processing. This performance level is a dramatic extension of the team's previous 15 LPW large area illumination device. The fundamental material system was based upon commercial polymer materials. The team was largely able to achieve these goals, and was able to deliver to DOE a 90 lumen illumination source that had an average performance of 34 LPW a 1000 cd/m{sup 2} with peak performances near 40LPW. The average color temperature is 3200K and the calculated CRI 85. The device operated at a brightness of approximately 1000cd/m{sup 2}. The use of multiple emission colors particularly red and blue, provided additional degrees of design flexibility in achieving white light, but also required the use of a multilayered structure to separate the different recombination zones and prevent interconversion of blue emission to red emission. The use of commercial materials had the advantage that improvements by the chemical manufacturers in charge transport efficiency, operating life and material purity could be rapidly incorporated without the expenditure of additional effort. The program was designed to take maximum advantage of the known characteristics of these material and proceeded in seven steps. (1) Identify the most promising materials, (2) assemble them into multi-layer structures to control excitation and transport within the OLED, (3) identify materials development needs that would optimize performance within multilayer structures, (4) build a prototype that demonstrates the potential entitlement of the novel multilayer OLED architecture (5) integrate all of the developments to find the single best materials set to implement the novel multilayer architecture, (6) further optimize the best materials set, (7) make a large area high illumination quality white OLED. A photo of the final deliverable is shown. In

  13. Studies in Illumination. 1. The Hygienic Conditions of Illumination in Certain Post Offices, Especially Relating to Visual Defects and Efficiency

    DTIC Science & Technology

    1924-07-01

    lights having been installed or the post office having been repainted. 18 STUDIES IN ILUMINATION . The eastern portionQf this floor is occupied by the...illumination on the face of case 66 was measured. The: results are given inTable VI. TABLE VI.- Ilumination on the vertical face of a letter separation case...and the mean natural illumination near the windows, 12.9 foot-candles. 36 STUDIES IN ILLUMINATION. TABLE XIII.- Ilumination , basement, general post

  14. Illuminance and luminance distributions of a prototype ambient illumination system for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Mullican, R. C.; Hayes, B. C.

    1991-01-01

    Preliminary results of research conducted in the late 1970's indicate that perceptual qualities of an enclosure can be influenced by the distribution of illumination within the enclosure. Subjective impressions such as spaciousness, perceptual clarity, and relaxation or tenseness, among others, appear to be related to different combinations of surface luminance. A prototype indirect ambient illumination system was developed which will allow crew members to alter surface luminance distributions within an enclosed module, thus modifying perceptual cues to match crew preferences. A traditional lensed direct lighting system was compared to the prototype utilizing the full-scale mockup of Space Station Freedom developed by Marshall Space Flight Center. The direct lensed system was installed in the habitation module with the indirect prototype deployed in the U.S. laboratory module. Analysis centered on the illuminance and luminance distributions resultant from these systems and the implications of various luminaire spacing options. All test configurations were evaluated for compliance with NASA Standard 3000, Man-System Integration Standards.

  15. Low-Cost Illumination-Grade LEDs

    SciTech Connect

    Epler, John

    2013-08-31

    Solid State Lighting is a cost-effective, energy-conserving technology serving a rapidly expand- ing multi-billion dollar market. This program was designed to accelerate this lighting revolution by reducing the manufacturing cost of Illumination-Grade LEDs. The technical strategy was to investigate growth substrate alternatives to standard planar sapphire, select the most effective and compatible option, and demonstrate a significant increase in Lumen/$ with a marketable LED. The most obvious alternate substrate, silicon, was extensively studied in the first two years of the program. The superior thermal and mechanical properties of Si were expected to improve wavelength uniformity and hence color yield in the manufacture of high-power illumination- grade LEDs. However, improvements in efficiency and epitaxy uniformity on standard c-plane sapphire diminished the advantages of switching to Si. Furthermore, the cost of sapphire decreased significantly and the cost of processing Si devices using our thin film process was higher than expected. We concluded that GaN on Si was a viable technology but not a practical option for Philips Lumileds. Therefore in 2012 and 2013, we sought and received amendments which broadened the scope to include other substrates and extended the time of execution. Proprietary engineered substrates, off-axis (non-c-plane) sapphire, and c-plane patterned sapphire substrates (PSS) were all investigated in the final 18 months of this program. Excellent epitaxy quality was achieved on all three candidates; however we eliminated engineered substrates and non-c-plane sapphire because of their higher combined cost of substrate, device fabrication and packaging. Ultimately, by fabricating a flip-chip (FC) LED based upon c-plane PSS we attained a 42% reduction in LED manufacturing cost relative to our LUXEON Rebel product (Q1-2012). Combined with a flux gain from 85 to 102 Lm, the LUXEON Q delivered a 210% increase in Lm/$ over this time period. The

  16. Tachistoscopic illumination and masking of real scenes

    PubMed Central

    Chichka, David; Philbeck, John W.; Gajewski, Daniel A.

    2014-01-01

    Tachistoscopic presentation of scenes has been valuable for studying the emerging properties of visual scene representations. The spatial aspects of this work have generally been focused on the conceptual locations (e.g., next to the refrigerator) and the directional locations of objects in 2D arrays and/or images. Less is known about how the perceived egocentric distance of objects develops. Here we describe a novel system for presenting brief glimpses of a real-world environment, followed by a mask. The system includes projectors with mechanical shutters for projecting the fixation and masking images, a set of LED floodlights for illuminating the environment, and computer-controlled electronics to set the timing and initiate the process. Because a real environment is used, most visual distance and depth cues may be manipulated using traditional methods. The system is inexpensive, robust, and its components are readily available in the marketplace. This paper describes the system and the timing characteristics of each component. Verification of the ability to control exposure to time scales as low as a few milliseconds is demonstrated. PMID:24519496

  17. Efficient White SSL Component for General Illumination

    SciTech Connect

    Sean Evans

    2011-01-31

    Cree has developed a new, high-efficiency, low-cost, light emitting diode (LED) module that should be capable of replacing standard, halogen, fluorescent and metal halide lamps based on the total cost of ownership. White LEDs are produced by combining one or more saturated color LEDs with a phosphor or other light down-converting media to achieve white broad-band illumination. This two year project addressed LED chip, package and phosphor efficiency improvements to establish a technology platform suitable for low-cost, high-efficiency commercial luminaires. New phosphor materials with improved quantum efficiency at 'real-life' operating conditions were developed along with new package technology to improve the efficiency of warm white LED modules compared to the baseline technology. Specifically, Cree has successfully demonstrated warm white LED modules providing 540 lumens at a correlated color temperature (CCT) of 3000 K. The LED module had an efficacy of 102.8 lumens per watt (LPW) using 1 mm2 chips biased at 350 mA - a 27% improvement over the technology at project start (81 LPW at 3000K). The white modules also delivered an efficacy of 88 LPW at elevated junction temperatures of 125 C. In addition, a proof-of-concept 4-inch downlight luminaire produced a flux of 1183 lumens at a CCT of 2827 K and a color rendering index (CRI) of 80 using this project's phosphor developments.

  18. Illumination-invariant hand gesture recognition

    NASA Astrophysics Data System (ADS)

    Mendoza-Morales, América I.; Miramontes-Jaramillo, Daniel; Kober, Vitaly

    2015-09-01

    In recent years, human-computer interaction (HCI) has received a lot of interest in industry and science because it provides new ways to interact with modern devices through voice, body, and facial/hand gestures. The application range of the HCI is from easy control of home appliances to entertainment. Hand gesture recognition is a particularly interesting problem because the shape and movement of hands usually are complex and flexible to be able to codify many different signs. In this work we propose a three step algorithm: first, detection of hands in the current frame is carried out; second, hand tracking across the video sequence is performed; finally, robust recognition of gestures across subsequent frames is made. Recognition rate highly depends on non-uniform illumination of the scene and occlusion of hands. In order to overcome these issues we use two Microsoft Kinect devices utilizing combined information from RGB and infrared sensors. The algorithm performance is tested in terms of recognition rate and processing time.

  19. Illumination Criteria in Imaging System Design for Security Applications,

    DTIC Science & Technology

    1979-12-01

    conjunction with pole spacing and distance from the critical area to be illuminated. Streetlights or roadway luminaires are characterized by their light...found best suited for perimeter illumination, when CCTV is employed, are the floodlights and the -o 4, , streetlights (roadway luminaires). The... streetlights are preferred, however, because the asymmetrical light distribution simplifies the system architecture when designing for uniformity of The

  20. Fraunhofer Diffraction Patterns from Apertures Illuminated with Nonparallel Light.

    ERIC Educational Resources Information Center

    Klingsporn, Paul E.

    1979-01-01

    Discusses several aspects of Fraunhofer diffraction patterns from apertures illuminated by diverging light. Develops a generalization to apertures of arbitrary shape which shows that the sizes of the pattern are related by a simple scale factor. Uses the Abbe theory of image formation by diffraction to discuss the intensity of illumination of the…

  1. 46 CFR 112.43-11 - Illumination for launching operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Illumination for launching operations. 112.43-11 Section 112.43-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-11 Illumination for...

  2. 46 CFR 112.43-11 - Illumination for launching operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Illumination for launching operations. 112.43-11 Section 112.43-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-11 Illumination for...

  3. 46 CFR 112.43-11 - Illumination for launching operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Illumination for launching operations. 112.43-11 Section 112.43-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-11 Illumination for...

  4. 46 CFR 112.43-11 - Illumination for launching operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Illumination for launching operations. 112.43-11 Section 112.43-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-11 Illumination for...

  5. Lightness of an object under two illumination levels.

    PubMed

    Zdravković, Suncica; Economou, Elias; Gilchrist, Alan

    2006-01-01

    Anchoring theory (Gilchrist et al, 1999 Psychological Review 106 795-834) predicts a wide range of lightness errors, including failures of constancy in multi-illumination scenes and a long list of well-known lightness illusions seen under homogeneous illumination. Lightness values are computed both locally and globally and then averaged together. Local values are computed within a given region of homogeneous illumination. Thus, for an object that extends through two different illumination levels, anchoring theory produces two values, one for the patch in brighter illumination and one for the patch in dimmer illumination. Observers can give matches for these patches separately, but they can also give a single match for the whole object. Anchoring theory in its current form is unable to predict these object matches. We report eight experiments in which we studied the relationship between patch matches and object matches. The results show that the object match represents a compromise between the match for the patch in the field of highest illumination and the patch in the largest field of illumination. These two principles are parallel to the rules found for anchoring lightness: highest luminance rule and area rule.

  6. Transfer between Pose and Illumination Training in Face Recognition

    ERIC Educational Resources Information Center

    Liu, Chang Hong; Bhuiyan, Md. Al-Amin; Ward, James; Sui, Jie

    2009-01-01

    The relationship between pose and illumination learning in face recognition was examined in a yes-no recognition paradigm. The authors assessed whether pose training can transfer to a new illumination or vice versa. Results show that an extensive level of pose training through a face-name association task was able to generalize to a new…

  7. 36 CFR 910.38 - Building exterior illumination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Building exterior... PENNSYLVANIA AVENUE DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.38 Building exterior illumination. Exterior illumination of a building shall be in conformance with the...

  8. 36 CFR 910.38 - Building exterior illumination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Building exterior... PENNSYLVANIA AVENUE DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.38 Building exterior illumination. Exterior illumination of a building shall be in conformance with the...

  9. Adaptive Ambient Illumination Based on Color Harmony Model

    NASA Astrophysics Data System (ADS)

    Kikuchi, Ayano; Hirai, Keita; Nakaguchi, Toshiya; Tsumura, Norimichi; Miyake, Yoichi

    We investigated the relationship between ambient illumination and psychological effect by applying a modified color harmony model. We verified the proposed model by analyzing correlation between psychological value and modified color harmony score. Experimental results showed the possibility to obtain the best color for illumination using this model.

  10. Evaluation of retinal illumination in coaxial fundus camera

    NASA Astrophysics Data System (ADS)

    de Oliveira, André O.; de Matos, Luciana; Castro Neto, Jarbas C.

    2016-09-01

    Retinal images are obtained by simultaneously illuminating and imaging the retina, which is achieved using a fundus camera. This device meets low light illumination of the fundus with high resolution and reflection free images. Although the current equipment presents a sophisticated solution, it is complex to align due to the high number of off-axis components. In this work, we substitute the complex illumination system by a ring of LEDs mounted coaxially to the imaging optical system, positioning it in the place of the holed mirror of the traditional optical design. We evaluated the impact of this substitution regarding to image quality (measured through the modulation transfer function) and illumination uniformity produced by this system on the retina. The results showed there is no change in image quality and no problem was detected concerning uniformity compared to the traditional equipment. Consequently, we avoided off-axis components, easing the alignment of the equipment without reducing both image quality and illumination uniformity.

  11. Template based illumination compensation algorithm for multiview video coding

    NASA Astrophysics Data System (ADS)

    Li, Xiaoming; Jiang, Lianlian; Ma, Siwei; Zhao, Debin; Gao, Wen

    2010-07-01

    Recently multiview video coding (MVC) standard has been finalized as an extension of H.264/AVC by Joint Video Team (JVT). In the project Joint Multiview Video Model (JMVM) for the standardization, illumination compensation (IC) is adopted as a useful tool. In this paper, a novel illumination compensation algorithm based on template is proposed. The basic idea of the algorithm is that the illumination of the current block has a strong correlation with its adjacent template. Based on this idea, firstly a template based illumination compensation method is presented, and then a template models selection strategy is devised to improve the illumination compensation performance. The experimental results show that the proposed algorithm can improve the coding efficiency significantly.

  12. Illuminate Knowledge Elements in Geoscience Literature

    NASA Astrophysics Data System (ADS)

    Ma, X.; Zheng, J. G.; Wang, H.; Fox, P. A.

    2015-12-01

    There are numerous dark data hidden in geoscience literature. Efficient retrieval and reuse of those data will greatly benefit geoscience researches of nowadays. Among the works of data rescue, a topic of interest is illuminating the knowledge framework, i.e. entities and relationships, embedded in documents. Entity recognition and linking have received extensive attention in news and social media analysis, as well as in bioinformatics. In the domain of geoscience, however, such works are limited. We will present our work on how to use knowledge bases on the Web, such as ontologies and vocabularies, to facilitate entity recognition and linking in geoscience literature. The work deploys an un-supervised collective inference approach [1] to link entity mentions in unstructured texts to a knowledge base, which leverages the meaningful information and structures in ontologies and vocabularies for similarity computation and entity ranking. Our work is still in the initial stage towards the detection of knowledge frameworks in literature, and we have been collecting geoscience ontologies and vocabularies in order to build a comprehensive geoscience knowledge base [2]. We hope the work will initiate new ideas and collaborations on dark data rescue, as well as on the synthesis of data and knowledge from geoscience literature. References: 1. Zheng, J., Howsmon, D., Zhang, B., Hahn, J., McGuinness, D.L., Hendler, J., and Ji, H. 2014. Entity linking for biomedical literature. In Proceedings of ACM 8th International Workshop on Data and Text Mining in Bioinformatics, Shanghai, China. 2. Ma, X. Zheng, J., 2015. Linking geoscience entity mentions to the Web of Data. ESIP 2015 Summer Meeting, Pacific Grove, CA.

  13. The DESI shutter with integrated fiber illumination system

    NASA Astrophysics Data System (ADS)

    Derwent, Mark A.; O'Brien, Thomas P.; Pappalardo, Daniel P.; Martini, Paul; Coker, Carl T.; Pogge, Richard W.

    2016-08-01

    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 40 million galaxies over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We describe the unique shutter design that incorporates a fiber illumination system into the shutter blade. When activated, the fiber illumination system directs intense 430-480nm wavelength light at the instrument's fiber slit in order to back-illuminate the telescope's focal plane and verify the location of the robotic fiber positioners. The back-illumination is typically active during science exposure read-outs and therefore requires the shutter to attenuate light by a factor of at least 107. This paper describes how we have integrated the fiber illumination system into the shutter blade, as well as incorporated an inflatable seal around the shutter aperture to achieve the light attenuation requirement. We also present lab results that characterize the fiber illumination and shutter attenuation. Finally, we discuss the control scheme that executes exposure and fiber illumination modes, and meets the shutter timing requirements.

  14. Customized illumination shapes for 193nm immersion lithography

    NASA Astrophysics Data System (ADS)

    Ling, Moh Lung; Chua, Gek Soon; Lin, Qunying; Tay, Cho Jui; Quan, Chenggen

    2008-03-01

    In this paper, a study on customized illumination shape configurations as resolution enhancement for 45nm technology node will be presented. Several new source shape configurations will be explored through simulation based on 193nm immersion lithography on 6% Attenuated Phase Shift Mask. Forbidden pitch effect is commonly encountered in the application of off axis illumination (OAI). The illumination settings are often optimized to allow maximum process window for a pitch. This is done by creating symmetrical distribution of diffraction order on the pupil plane. However, at other pitch, the distribution of diffraction order on the pupil plane results in severe degradation in image contrast and results in significant critical dimension (CD) fluctuation. The problematic pitch is often known as forbidden pitch. It has to be avoided in the design and thus limited the pitch range to be imaged for particular illumination. An approach to modify off axis illumination to minimize the effect of forbidden pitch is explored in this study. The new customized shape for one dimensional line and space pattern is modified from current off axis illumination. Simulation study is done to evaluate the performance some customized shapes. The extent of CD fluctuation and CD through pitch uniformity is analyzed to determine the performance enhancement of the new illumination shapes. From simulation result, the proposed modification have significantly improved the through pitch performance and minimized the effect of forbidden pitch.

  15. Wavelet-based illumination invariant preprocessing in face recognition

    NASA Astrophysics Data System (ADS)

    Goh, Yi Zheng; Teoh, Andrew Beng Jin; Goh, Kah Ong Michael

    2009-04-01

    Performance of a contemporary two-dimensional face-recognition system has not been satisfied due to the variation in lighting. As a result, many works of solving illumination variation in face recognition have been carried out in past decades. Among them, the Illumination-Reflectance model is one of the generic models that is used to separate the individual reflectance and illumination components of an object. The illumination component can be removed by means of image-processing techniques to regain an intrinsic face feature, which is depicted by the reflectance component. We present a wavelet-based illumination invariant algorithm as a preprocessing technique for face recognition. On the basis of the multiresolution nature of wavelet analysis, we decompose both illumination and reflectance components from a face image in a systematic way. The illumination component wherein resides in the low-spatial-frequency subband can be eliminated efficiently. This technique works out very advantageously for achieving higher recognition performance on YaleB, CMU PIE, and FRGC face databases.

  16. Rock fracture image acquisition with both visible and ultraviolet illuminations

    NASA Astrophysics Data System (ADS)

    Wang, Weixing; Hakami, Eva

    2006-02-01

    Swedish Nuclear Fuel and Waste Management Company (SKB) have identified the need for a better understanding of radionuclide transport and retention processes in fractured rock since 1994. In the study, the first hard problem is to obtain rock fracture images of a good quality, since rock surface is very rough, and composed of complicated and multiple fractures, as a result, image acquisition is the first important. As a cooperation project between Sweden and China, we sampled a number of rock specimens for analyzing rock fracture network by visible and ultraviolet image technique, in the field. The samples are resin injected, in which way; opened fractures can be seen clearly by means of UV light illumination, and the rock surface information can be obtained by using visible optical illumination. We used different digital cameras and microscope to take images by two illuminations. From the same samples; we found that UV illumination image gives the clear information of fracture opening or closing, and the visible optical illumination gives the information of the rock surface (e.g. filling materials inside of fractures). By applying this technique, the minimum width of rock fracture 0.01 mm can be analyzed. This paper presents: (1) Rock fracture image acquiring techniques; (2) Rock fracture image acquisition by using UV light illumination and visible optical illumination; and (3) Conclusions. The studied method can be used both in the field and a laboratory.

  17. Spectral image analysis of mutual illumination between florescent objects.

    PubMed

    Tominaga, Shoji; Kato, Keiji; Hirai, Keita; Horiuchi, Takahiko

    2016-08-01

    This paper proposes a method for modeling and component estimation of the spectral images of the mutual illumination phenomenon between two fluorescent objects. First, we briefly describe the bispectral characteristics of a single fluorescent object, which are summarized as a Donaldson matrix. We suppose that two fluorescent objects with different bispectral characteristics are located close together under a uniform illumination. Second, we model the mutual illumination between two objects. It is shown that the spectral composition of the mutual illumination is summarized with four components: (1) diffuse reflection, (2) diffuse-diffuse interreflection, (3) fluorescent self-luminescence, and (4) interreflection by mutual fluorescent illumination. Third, we develop algorithms for estimating the spectral image components from the observed images influenced by the mutual illumination. When the exact Donaldson matrices caused by the mutual illumination influence are unknown, we have to solve a non-linear estimation problem to estimate both the spectral functions and the location weights. An iterative algorithm is then proposed to solve the problem based on the alternate estimation of the spectral functions and the location weights. In our experiments, the feasibility of the proposed method is shown in three cases: the known Donaldson matrices, weak interreflection, and strong interreflection.

  18. Seasonal variation in human illumination exposure at two different latitudes.

    PubMed

    Cole, R J; Kripke, D F; Wisbey, J; Mason, W J; Gruen, W; Hauri, P J; Juarez, S

    1995-12-01

    The authors measured ambient illumination exposure in healthy volunteers in San Diego, California (latitude 32 degrees 43' N, n = 30), and Rochester, Minnesota (latitude 44 degrees 1' N, n = 24), during each of the four quarters of the year, which were centered on the solstices and equinoxes. Subjects wore photosensors on their wrists and lapels (or foreheads while in bed) 24 h per day for an average of 5-6 days per quarter. The maximum of the two illumination readings was stored each minute. Annual average time spent per day in outdoor illumination (> or = 1000 lux) was significantly higher in San Diego than it was in Rochester (p < .04). Daily durations of illumination at or exceeding thresholds of 1, 10, 100, 1000, and 10,000 lux were highly seasonal in the sample as a whole (p < .01 at 1 lux, p < .0001 at other thresholds). Seasonal variation in outdoor illumination was far more pronounced in Rochester than it was in San Diego (interaction p < .001) but remained significant in San Diego (p < or = .03). Seasonal variation in indoor illumination was generally similar in the two cities. The median Rochester subject experienced illumination > or = 1000 lux for 2 h 23 min per day during summer and 23 min per day during winter. The corresponding times in San Diego were 2 h 10 min and 1 h 20 min. Neither age nor gender predicted illumination duration at any level. Both season and geographic location strongly influenced human illumination exposure, and behavior (choice of indoor vs. outdoor environment) was the most important mediating factor.

  19. Research on infrared imaging illumination model based on materials

    NASA Astrophysics Data System (ADS)

    Hu, Hai-he; Feng, Chao-yin; Guo, Chang-geng; Zheng, Hai-jing; Han, Qiang; Hu, Hai-yan

    2013-09-01

    In order to effectively simulate infrared features of the scene and infrared high light phenomenon, Based on the visual light illumination model, according to the optical property of all material types in the scene, the infrared imaging illumination models are proposed to fulfill different materials: to the smooth material with specular characteristic, adopting the infrared imaging illumination model based on Blinn-Phone reflection model and introducing the self emission; to the ordinary material which is similar to black body without highlight feature, ignoring the computation of its high light reflection feature, calculating simply the material's self emission and its reflection to the surrounding as its infrared imaging illumination model, the radiation energy under zero range of visibility can be obtained according to the above two models. The OpenGl rendering technology is used to construct infrared scene simulation system which can also simulate infrared electro-optical imaging system, then gets the synthetic infrared images from any angle of view of the 3D scenes. To validate the infrared imaging illumination model, two typical 3D scenes are made, and their infrared images are calculated to compare and contrast with the real collected infrared images obtained by a long wave infrared band imaging camera. There are two major points in the paper according to the experiment results: firstly, the infrared imaging illumination models are capable of producing infrared images which are very similar to those received by thermal infrared camera; secondly, the infrared imaging illumination models can simulate the infrared specular feature of relative materials and common infrared features of general materials, which shows the validation of the infrared imaging illumination models. Quantitative analysis shows that the simulation images are similar to the collected images in the aspects of main features, but their histogram distribution does not match very well, the

  20. Visual inspection system with flexible illumination and autofocusing

    NASA Astrophysics Data System (ADS)

    Roh, Young Jun; Lee, Duk-Young; Kim, Min-Young; Cho, Hyungsuck

    2002-10-01

    The visual information obtained from CCD camera is vulnerable to external illumination and the surface reflection properties of object images. Thus, the success of extracting aimed features from images depends mostly on the appropriate design of illumination. This paper presents a visual inspection system that is equipped with a flexible illumination and an auto-focusing unit. The proposed illumination system consists of a three-layered LED illumination device and the controllable diffusers. Each layer is composed of LEDs arranged in a ring type, and a controllable diffuser unit is located in front of each layer. The diffuser plays a role of diffusing lights emitted from the LEDs so that the characteristics of illumination is made varied. This combined configuration of the LED light sources and the adjustable diffuser creates the various lighting conditions. In addition to this flexible illumination function, the vision system is equipped with an auto-focusing unit composed of a pattern projector and a working distance adjustable zoom camera. For the auto-focusing, hill climbing algorithm is used here based on a reliable focus measure that is defined as the variance of high frequency terms in an image. Through a series of experiments, the influence of the illumination system on image quality is analyzed for various objects that have different reflective properties and shapes. As an example study, the electrical parts inspection is investigated. In this study, several types of chips with different sizes and heights are segmented and focused automatically, and then analyzed for part inspection. The results obtained from a series of experiments confirm the usefulness of the proposed system and the effectiveness of the illumination and focusing method.

  1. Novel non-imaging optic design for uniform illumination

    NASA Astrophysics Data System (ADS)

    Babadi, S.; Ramirez-Iniguez, R.; Boutaleb, T.; Mallick, T.

    2016-03-01

    The Dielectric Totally Internally Reflecting Concentrator (DTIRC) has been developed in the past for wireless infrared communications and solar energy applications. This paper proposes a novel non-imaging optic design based on the DTIRC family of concentrators for use in illumination applications. The novel optic can be integrated with a light emitting diode (LED) and can be tailored to meet specific requirements. The proposed optic can be used as a first or secondary optic to provide uniform illumination within a circular footprint with a desired radius. The results from this work show that, with the optimised DTIRC, it is possible to achieve a uniformity of illuminance of over 95%.

  2. Dark-field illuminated reflectance fiber bundle endoscopic microscope

    NASA Astrophysics Data System (ADS)

    Liu, Xuan; Huang, Yong; Kang, Jin U.

    2011-04-01

    We propose a reflectance fiber bundle microscope using a dark-field illumination configuration for applications in endoscopic medical imaging and diagnostics. Our experiment results show that dark-field illumination can effectively suppress strong specular reflection from the proximal end of the fiber bundle. We realized a lateral resolution of 4.4 μm using the dark-field illuminated fiber bundle configuration. To demonstrate the feasibility of using the system to study cell morphology, we obtained still and video images of two thyroid cancer cell lines. Our results clearly allow differentiation of different cancer cell types.

  3. Concept of epitaxial silicon structures for edge illuminated solar cells

    NASA Astrophysics Data System (ADS)

    Sarnecki, J.; Gawlik, G.; Teodorczyk, M.; Jeremiasz, O.; Kozłowski, R.; Lipiński, D.; Krzyżak, K.; Brzozowski, A.

    2011-12-01

    A new concept of edge illuminated solar cells (EISC) based on silicon epitaxial technique has been proposed. In this kind of photovoltaic (PV) devices, sun-light illuminates directly a p-n junction through the edge of the structure which is perpendicular to junction surface. The main motivation of the presented work is preparation of a working model of an edge-illuminated silicon epitaxial solar cell sufficient to cooperation with a luminescent solar concentrator (LSC) consisted of a polymer foil doped with a luminescent material. The technological processes affecting the cell I-V characteristic and PV parameters are considered.

  4. IODC 2014 Illumination design problem: the Cinderella Lamp

    NASA Astrophysics Data System (ADS)

    Cassarly, William J.

    2014-12-01

    For the 3rd time, the International Optical Design Conference (IODC) included an Illumination Design contest. This year, the contest involved designing the illuminator to project the 1950 Walt Disney "Cinderella" movie using a box of optical knick-knacks. The goal of the problem was to provide the highest screen lumens with greater than 30% uniformity. There were 12 entries from 3 different countries. Three different commercial optical/illumination design packages were used. The winning solution, provided by Alois Herkommer, provided 371 screen lumens.

  5. An inexpensive programmable illumination microscope with active feedback

    PubMed Central

    Tompkins, Nathan; Fraden, Seth

    2016-01-01

    We have developed a programmable illumination system capable of tracking and illuminating numerous objects simultaneously using only low-cost and reused optical components. The active feedback control software allows for a closed-loop system that tracks and perturbs objects of interest automatically. Our system uses a static stage where the objects of interest are tracked computationally as they move across the field of view allowing for a large number of simultaneous experiments. An algorithmically determined illumination pattern can be applied anywhere in the field of view with simultaneous imaging and perturbation using different colors of light to enable spatially and temporally structured illumination. Our system consists of a consumer projector, camera, 35-mm camera lens, and a small number of other optical and scaffolding components. The entire apparatus can be assembled for under $4,000. PMID:27642182

  6. On the spectral quality of scanner illumination with LEDs

    NASA Astrophysics Data System (ADS)

    Cui, Chengwu

    2013-01-01

    Document scanner illumination has evolved along with general illumination technologies. LEDs have become more and more popular as the illumination sources for document scanning. LED technologies provide a wide range of choices both in terms of structural design and spectral compositions. In this report, we examine some popular LED technologies used for document scanner. We evaluate the color rendering performance of scanner models with different illumination technologies by examining their rendering of the Macbeth ColorChecker™ in sRGB. We found that more phosphors in phosphor conversion types of white LEDs may not be necessarily advantageous in terms of scanner color rendering performance. Also CIS type of scanner may be sensitive to the peak wavelength shift and can be particularly problematic when the peaks are out of certain range.

  7. Circular, explosion-proof lamp provides uniform illumination

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Circular explosion-proof fluorescent lamp is fitted around a TV camera lens to provide shadowless illumination with a low radiant heat flux. The lamp is mounted in a transparent acrylic housing sealed with clear silicone rubber.

  8. Face recognition under variable illumination via sparse representation of patches

    NASA Astrophysics Data System (ADS)

    Fan, Shouke; Liu, Rui; Feng, Weiguo; Zhu, Ming

    2013-10-01

    The objective of this work is to recognize faces under variations in illumination. Previous works have indicated that the variations in illumination can dramatically reduce the performance of face recognition. To this end - ;an efficient method for face recognition which is robust under variable illumination is proposed in this paper. First of all, a discrete cosine transform(DCT) in the logarithm domain is employed to preprocess the images, removing the illumination variations by discarding an appropriate number of low-frequency DCT coefficients. Then, a face image is partitioned into several patches, and we classify the patches using Sparse Representation-based Classification, respectively. At last, the identity of a test image can be determined by the classification results of its patches. Experimental results on the Yale B database and the CMU PIE database show that excellent recognition rates can be achieved by the proposed method.

  9. Two bumblebee genomes illuminate the route to advanced social living

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Social living represents a major evolutionary transition. Primitively eusocial bumblebees are uniquely placed to illuminate the evolutionary route from solitary to highly eusocial insect societies, for which molecular level information is largely lacking. Additionally, bumblebees are invaluable natu...

  10. Active illuminated space object imaging and tracking simulation

    NASA Astrophysics Data System (ADS)

    Yue, Yufang; Xie, Xiaogang; Luo, Wen; Zhang, Feizhou; An, Jianzhu

    2016-10-01

    Optical earth imaging simulation of a space target in orbit and it's extraction in laser illumination condition were discussed. Based on the orbit and corresponding attitude of a satellite, its 3D imaging rendering was built. General simulation platform was researched, which was adaptive to variable 3D satellite models and relative position relationships between satellite and earth detector system. Unified parallel projection technology was proposed in this paper. Furthermore, we denoted that random optical distribution in laser-illuminated condition was a challenge for object discrimination. Great randomicity of laser active illuminating speckles was the primary factor. The conjunction effects of multi-frame accumulation process and some tracking methods such as Meanshift tracking, contour poid, and filter deconvolution were simulated. Comparison of results illustrates that the union of multi-frame accumulation and contour poid was recommendable for laser active illuminated images, which had capacities of high tracking precise and stability for multiple object attitudes.

  11. Illumination from space with orbiting solar-reflector spacecraft

    NASA Technical Reports Server (NTRS)

    Canady, J. E., Jr.; Allen, J. L., Jr.

    1982-01-01

    The feasibility of using orbiting mirrors to reflect sunlight to Earth for several illumination applications is studied. A constellation of sixteen 1 km solar reflector spacecraft in geosynchronous orbit can illuminate a region 333 km in diameter to 8 lux, which is brighter than most existing expressway lighting systems. This constellation can serve one region all night long or can provide illumination during mornings and evenings to five regions across the United States. Preliminary cost estimates indicate such an endeavor is economically feasible. The studies also explain how two solar reflectors can illuminate the in-orbit nighttime operations of Space Shuttle. An unfurlable, 1 km diameter solar reflector spacecraft design concept was derived. This spacecraft can be packaged in the Space, Shuttle, transported to low Earth orbit, unfurled, and solar sailed to operational orbits up to geosynchronous. The necessary technical studies and improvements in technology are described, and potential environmental concerns are discussed.

  12. PHYTOCHEMICAL CONTENT IN BLUEBERRIES IS INFLUENCED BY UV ILLUMINATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The levels of phytochemicals in blueberries were found to increase after illumination with UV-C light. Phytochemicals affected included resveratrol, myricetin 3-arabinoside, quercetin 3-galactoside, quercetin 3-arabinoside, quercetin derivative, kaempferol 3-glucoside, delphinidin-3-galactoside, cy...

  13. Critical illumination condenser for x-ray lithography

    DOEpatents

    Cohen, S.J.; Seppala, L.G.

    1998-04-07

    A critical illumination condenser system is disclosed, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 {micro}m source and requires a magnification of 26. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth. 6 figs.

  14. Critical illumination condenser for x-ray lithography

    DOEpatents

    Cohen, Simon J.; Seppala, Lynn G.

    1998-01-01

    A critical illumination condenser system, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 .mu.m source and requires a magnification of 26.times.. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth.

  15. A multilinear constraint on dichromatic planes for illumination estimation.

    PubMed

    Toro, Javier; Funt, Brian

    2007-01-01

    A new multilinear constraint on the color of the scene illuminant based on the dichromatic reflection model is proposed. The formulation avoids the problem, common to previous dichromatic methods, of having to first identify pixels corresponding to the same surface material. Once pixels from two or more materials have been identified, their corresponding dichromatic planes can be intersected to yield the illuminant color. However, it is not always easy to determine which pixels from an arbitrary region of an image belong to which dichromatic plane. The image region may cover an area of the scene encompassing several different materials and, hence, pixels from several different dichromatic planes. The new multilinear constraint accounts for this multiplicity of materials and provides a mechanism for choosing the most plausible illuminant from a finite set of candidate illuminants. The performance of this new method is tested on a database of real images.

  16. Illumination requirements for operating a space remote manipulator

    NASA Technical Reports Server (NTRS)

    Chandlee, George O.; Smith, Randy L.; Wheelwright, Charles D.

    1993-01-01

    Critical issues and requirements involved in illuminating remote manipulator operations in space help establish engineering designs for these manipulators. A remote manipulator is defined as any mechanical device that is controlled indirectly or from a distance by a human operator for the purpose of performing potentially dangerous or hazardous tasks to increase safety, reliability, and efficiency. Future space flights will rely on remote manipulators for a variety of tasks including satellite repair and servicing, structural assembly, data collection and analysis, and performance of contingency tasks. Carefully designed illumination of these manipulators will assure that these tasks will be completed efficiently and successfully. Studies concerning the influence of illumination on operation of a remote manipulator are few. Available results show that illumination can influence how successfully a human operates a remote manipulator. The intent of this study was to more fully examine this topic.

  17. Fiber Coupled Laser Diodes with Even Illumination Pattern

    NASA Technical Reports Server (NTRS)

    Howard, Richard T. (Inventor)

    2007-01-01

    An optical fiber for evenly illuminating a target. The optical fiber is coupled to a laser emitting diode and receives laser light. The la ser light travels through the fiber optic and exits at an exit end. T he exit end has a diffractive optical pattern formed thereon via etch ing, molding or cutting, to reduce the Gaussian profile present in co nventional fiber optic cables The reduction of the Gaussian provides an even illumination from the fiber optic cable.

  18. Transfer function analysis in epi-illumination Fourier ptychography

    PubMed Central

    Pacheco, Shaun; Salahieh, Basel; Milster, Tom; Rodriguez, Jeffrey J.; Liang, Rongguang

    2016-01-01

    This letter explores Fourier ptychography (FP) using epi-illumination. The approach effectively modifies the FP transfer function to be coherent-like out to the incoherent limit of twice the numerical aperture over the wavelength 2NA/λ. Images reconstructed using this approach are shown to have higher contrast at finer details compared with images using incoherent illumination, indicating that the FP transfer function is superior in high spatial frequency regions. PMID:26565870

  19. Quantum Illumination-Based Target Detection and Discrimination

    DTIC Science & Technology

    2014-06-30

    demonstrated high signal-to-noise ratio (SNR) quantum-illumination target detection in a lossy, noisy environment using an optical parametric amplifier...Research Triangle Park, NC 27709-2211 quantum communication, target detection, entanglement, parametric downconversion, optical parametric amplifiers...illumination target detection in a lossy, noisy environment using an optical parametric amplifier (OPA) receiver, and explored the SNR’s dependence on

  20. Long duration exposure facility solar illumination data package

    NASA Technical Reports Server (NTRS)

    Berrios, William M.; Sampair, Thomas

    1990-01-01

    A post flight solar illumination data package was created by the LDEF thermal analysis data group in support of the LDEF science office data group. The data presented was prepared with the Thermal Radiation Analysis System (TRASYS) program. Ground tracking data was used to calculate daily orbital beta angles for the calculation of resultant fluxes. This data package will be useful in calculation of solar illumination fluent for a variety of beta angle orbital conditions encountered during the LDEF mission.

  1. Accretion Disk Illumination in Schwarzschild and Kerr Geometries: Fitting Formulae

    NASA Astrophysics Data System (ADS)

    Fukumura, Keigo; Kazanas, Demosthenes

    2007-07-01

    We describe the methodology and compute the illumination of geometrically thin accretion disks around black holes of arbitrary spin parameter a exposed to the radiation of a pointlike isotropic source at arbitrary height above the disk on its symmetry axis. We then provide analytic fitting formulae for the illumination as a function of the source height h and the black hole angular momentum a. We find that for a source on the disk symmetry axis and with h/M>3, the main effect of the parameter a is allowing the disk to extend to smaller radii (approaching r/M-->1 as a/M-->1) and thus allowing the illumination of regions of much higher rotational velocity and redshift. We also compute the illumination profiles for anisotropic emission associated with the motion of the source relative to the accretion disk and present the fractions of photons absorbed by the black hole, intercepted by the disk, or escaping to infinity for both isotropic and anisotropic emission for a/M=0 and 0.99. As the anisotropy (of a source approaching the disk) increases, the illumination profile reduces (approximately) to a single power law, whose index q, because of absorption of the beamed photons by the black hole, saturates to a value no higher than q>~3. Finally, we compute the fluorescent Fe line profiles associated with the specific illumination and compare them among various cases.

  2. Lunar South Pole Illumination: Review, Reassessment, and Power System Implications

    NASA Technical Reports Server (NTRS)

    Fincannon, James

    2007-01-01

    This paper reviews past analyses and research related to lunar south pole illumination and presents results of independent illumination analyses using an analytical tool and a radar digital elevation model. The analysis tool enables assessment at most locations near the lunar poles for any time and any year. Average illumination fraction, energy storage duration, solar/horizon terrain elevation profiles and illumination fraction profiles are presented for various highly illuminated sites which have been identified for manned or unmanned operations. The format of the data can be used by power system designers to develop mass optimized solar and energy storage systems. Data are presented for the worse case lunar day (a critical power planning bottleneck) as well as three lunar days during lunar south pole winter. The main site under consideration by present lunar mission planners (on the Crater Shackleton rim) is shown to have, for the worse case lunar day, a 0.71 average illumination fraction and 73 to 117 hours required for energy storage (depending on power system type). Linking other sites and including towers at either site are shown to not completely eliminate the need for energy storage.

  3. Simulation of illumination for machine vision and inspection

    NASA Astrophysics Data System (ADS)

    Guivens, Norman R., Jr.

    1994-01-01

    Illumination subsystems are critical elements of most machine vision and inspection systems. The linear response of most optical detectors generally requires much more uniform illumination than the logarithmic response of the human eye to achieve a similar level of performance. Excessive illumination can saturate optical detector elements, while insufficient illumination causes excessive shot noise that can cripple system performance. Speckle from coherent or partially coherent illumination can also affect system performance. Computer simulations of machine vision and inspection systems, like SPARTA's SENSORSIM, permit accurate analysis of various illumination designs to determine their suitability for a particular application. These simulations permit rapid analysis of system configurations and variation of system parameters to identify optimal designs on a price/performance curve. SENSORSIM can also provide images or other signatures at intermediate stages of the generation process for isolation and analysis sources of degradation in a sensor system. This sort of analysis often is not possible in laboratory experiments. Although models of more limited scope may be useful for some analyses, such models cannot support analysis of phenomena that depend upon interaction among several components or subsystems. Thus, simulations like SENSORSIM provide an invaluable capability for optimizing the cost and performance of optical sensor systems.

  4. Off-axis illumination direct-to-digital holography

    DOEpatents

    Thomas, Clarence E.; Price, Jeffery R.; Voelkl, Edgar; Hanson, Gregory R.

    2004-06-08

    Systems and methods are described for off-axis illumination direct-to-digital holography. A method of recording an off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis, includes: reflecting a reference beam from a reference mirror at a non-normal angle; reflecting an object beam from an object at an angle with respect to an optical axis defined by a focusing lens; focusing the reference beam and the object beam at a focal plane of a digital recorder to form the off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; digitally recording the off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; Fourier analyzing the recorded off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes by transforming axes of the recorded off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes in Fourier space to sit on top of a heterodyne carrier frequency defined as an angle between the reference beam and the object beam; applying a digital filter to cut off signals around an original origin; and then performing an inverse Fourier transform.

  5. Nonuniformity Mitigation of Beam Illumination in Heavy Ion Inertial Fusion

    NASA Astrophysics Data System (ADS)

    Kawata, Shigeo; Noguchi, K.; Suzuki, T.; Kurosaki, T.; Barada, D.; Ma, Y. Y.; Ogoyski, A. I.

    2013-10-01

    In heavy ion inertial fusion wobbling heavy ion beam (HIB) illumination was proposed to realize a uniform implosion. The wobbling HIB axis oscillation is precisely controlled. The oscillating frequency may be several 100 MHz ~ 1 GHz. In the wobbling HIBs illumination, the illumination nonuniformity oscillates in time and space on a HIF target. The oscillating-HIB energy deposition may contribute to the reduction of the HIBs' illumination nonuniformity. Three-dimensional HIBs illumination computations presented here show that the few percent wobbling HIBs illumination nonuniformity oscillates with the same wobbling HIBs frequency. In general a perturbation of physical quantity would feature the instability onset. Normally the perturbation phase is unknown so that the instability growth is discussed with the growth rate. However, if the perturbation phase is known, the instability growth can be controlled by a superposition of perturbations; the well-known mechanism is a feedback control to compensate the displacement of physical quantity. If the perturbation is induced by, for example, a HIB axis wobbling, the perturbation phase could be controlled and the instability growth is mitigated by the superposition of the growing perturbations. Partly supported by JSPS, MEXT, CORE, ASHULA, Japan / US Cooperation program and ILE/Osaka University.

  6. Advanced illumination control algorithm for medical endoscopy applications

    NASA Astrophysics Data System (ADS)

    Sousa, Ricardo M.; Wäny, Martin; Santos, Pedro; Morgado-Dias, F.

    2015-05-01

    CMOS image sensor manufacturer, AWAIBA, is providing the world's smallest digital camera modules to the world market for minimally invasive surgery and one time use endoscopic equipment. Based on the world's smallest digital camera head and the evaluation board provided to it, the aim of this paper is to demonstrate an advanced fast response dynamic control algorithm of the illumination LED source coupled to the camera head, over the LED drivers embedded on the evaluation board. Cost efficient and small size endoscopic camera modules nowadays embed minimal size image sensors capable of not only adjusting gain and exposure time but also LED illumination with adjustable illumination power. The LED illumination power has to be dynamically adjusted while navigating the endoscope over changing illumination conditions of several orders of magnitude within fractions of the second to guarantee a smooth viewing experience. The algorithm is centered on the pixel analysis of selected ROIs enabling it to dynamically adjust the illumination intensity based on the measured pixel saturation level. The control core was developed in VHDL and tested in a laboratory environment over changing light conditions. The obtained results show that it is capable of achieving correction speeds under 1 s while maintaining a static error below 3% relative to the total number of pixels on the image. The result of this work will allow the integration of millimeter sized high brightness LED sources on minimal form factor cameras enabling its use in endoscopic surgical robotic or micro invasive surgery.

  7. Simultaneous cast shadows, illumination and geometry inference using hypergraphs.

    PubMed

    Panagopoulos, Alexandros; Wang, Chaohui; Samaras, Dimitris; Paragios, Nikos

    2013-02-01

    The cast shadows in an image provide important information about illumination and geometry. In this paper, we utilize this information in a novel framework in order to jointly recover the illumination environment, a set of geometry parameters, and an estimate of the cast shadows in the scene given a single image and coarse initial 3D geometry. We model the interaction of illumination and geometry in the scene and associate it with image evidence for cast shadows using a higher order Markov Random Field (MRF) illumination model, while we also introduce a method to obtain approximate image evidence for cast shadows. Capturing the interaction between light sources and geometry in the proposed graphical model necessitates higher order cliques and continuous-valued variables, which make inference challenging. Taking advantage of domain knowledge, we provide a two-stage minimization technique for the MRF energy of our model. We evaluate our method in different datasets, both synthetic and real. Our model is robust to rough knowledge of geometry and inaccurate initial shadow estimates, allowing a generic coarse 3D model to represent a whole class of objects for the task of illumination estimation, or the estimation of geometry parameters to refine our initial knowledge of scene geometry, simultaneously with illumination estimation.

  8. Shading-based Surface Detail Recovery under General Unknown Illumination.

    PubMed

    Xu, Di; Duan, Qi; Zheng, Jianmin; Zhang, Juyong; Cai, Jianfei; Cham, Tat-Jen

    2017-02-17

    Reconstructing the shape of a 3D object from multi-view images under unknown, general illumination is a fundamental problem in computer vision and high quality reconstruction is usually challenging especially when fine detail is needed and the albedo of the object is non-uniform. This paper introduces vertex overall illumination vectors to model the illumination effect and presents a total variation (TV) based approach for recovering surface details using shading and multi-view stereo (MVS). Behind the approach are the two important observations: (1) the illumination over the surface of an object often appears to be piece wise smooth and (2) the recovery of surface orientation is not sufficient for reconstructing the surface, which was often overlooked previously. Thus we propose to use TV to regularize the overall illumination vectors and use visual hull to constrain partial vertices. The reconstruction is formulated as a constrained TV-minimization problem that simultaneously treats the shape and illumination vectors as unknowns. An augmented Lagrangian method is proposed to quickly solve the TV-minimization problem. As a result, our approach is robust, stable and is able to efficiently recover high quality of surface details even when starting with a coarse model obtained using MVS. These advantages are demonstrated by extensive experiments on the state-of-the-art MVS database, which includes challenging objects with varying albedo.

  9. Illumination Conditions of the Lunar Polar Regions Using LOLA Topography

    NASA Technical Reports Server (NTRS)

    Mazarico, E.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.; Torrence, M. H.

    2011-01-01

    We use high-resolution altimetry data obtained by the Lunar Orbiter Laser Altimeter instrument onboard the Lunar Reconnaissance Orbiter to characterize present illumination conditions in the polar regions of the Moon. Compared to previous studies, both the spatial and temporal extent of the simulations are increased significantly, as well as the coverage (fill ratio) of the topographic maps used, thanks to the 28 Hz firing rate of the five-beam instrument. We determine the horizon elevation in a number of directions based on 240 m-resolution polar digital elevation models reaching down to 75 latitude. The illumination of both polar regions extending to 80 can be calculated for any geometry from those horizon longitudinal profiles. We validated our modeling with recent Lunar Reconnaissance Orbiter Wide-Angle Camera images. We assessed the extent of permanently shadowed regions (PSRs, defined as areas that never receive direct solar illumination), and obtained total areas generally larger than previous studies (12,866 and 16,055 km2, in the north and south respectively). We extended our direct illumination model to account for singly-scattered light, and found that every PSR does receive some amount of scattered light during the year. We conducted simulations over long periods (several 18.6-years lunar precession cycles) with a high temporal resolution (6 h), and identified the most illuminated locations in the vicinity of both poles. Because of the importance of those sites for exploration and engineering considerations, we characterized their illumination more precisely over the near future. Every year, a location near the Shackleton crater rim in the south polar region is sunlit continuously for 240 days, and its longest continuous period in total darkness is about 1.5 days. For some locations small height gains ( 10 m) can dramatically improve their average illumination and reduce the night duration, rendering some of those particularly attractive energy-wise as

  10. Illumination pattern optimization for fluorescence tomography: theory and simulation studies.

    PubMed

    Dutta, Joyita; Ahn, Sangtae; Joshi, Anand A; Leahy, Richard M

    2010-05-21

    Fluorescence molecular tomography is a powerful tool for 3D visualization of molecular targets and pathways in vivo in small animals. Owing to the high degrees of absorption and scattering of light through tissue, the fluorescence tomographic inverse problem is inherently ill-posed. In order to improve source localization and the conditioning of the light propagation model, multiple sets of data are acquired by illuminating the animal surface with different spatial patterns of near-infrared light. However, the choice of these patterns in most experimental setups is ad hoc and suboptimal. This paper presents a systematic approach for designing efficient illumination patterns for fluorescence tomography. Our objective here is to determine how to optimally illuminate the animal surface so as to maximize the information content in the acquired data. We achieve this by improving the conditioning of the Fisher information matrix. We parameterize the spatial illumination patterns and formulate our problem as a constrained optimization problem that, for a fixed number of illumination patterns, yields the optimal set of patterns. For geometric insight, we used our method to generate a set of three optimal patterns for an optically homogeneous, regular geometrical shape and observed expected symmetries in the result. We also generated a set of six optimal patterns for an optically homogeneous cuboidal phantom set up in the transillumination mode. Finally, we computed optimal illumination patterns for an optically inhomogeneous realistically shaped mouse atlas for different given numbers of patterns. The regularized pseudoinverse matrix, generated using the singular value decomposition, was employed to reconstruct the point spread function for each set of patterns in the presence of a sample fluorescent point source deep inside the mouse atlas. We have evaluated the performance of our method by examining the singular value spectra as well as plots of average spatial

  11. Spectrally optimal illuminations for diabetic retinopathy detection in retinal imaging

    NASA Astrophysics Data System (ADS)

    Bartczak, Piotr; Fält, Pauli; Penttinen, Niko; Ylitepsa, Pasi; Laaksonen, Lauri; Lensu, Lasse; Hauta-Kasari, Markku; Uusitalo, Hannu

    2017-01-01

    Retinal photography is a standard method for recording retinal diseases for subsequent analysis and diagnosis. However, the currently used white light or red-free retinal imaging does not necessarily provide the best possible visibility of different types of retinal lesions, important when developing diagnostic tools for handheld devices, such as smartphones. Using specifically designed illumination, the visibility and contrast of retinal lesions could be improved. In this study, spectrally optimal illuminations for diabetic retinopathy lesion visualization are implemented using a spectrally tunable light source based on digital micromirror device. The applicability of this method was tested in vivo by taking retinal monochrome images from the eyes of five diabetic volunteers and two non-diabetic control subjects. For comparison to existing methods, we evaluated the contrast of retinal images taken with our method and red-free illumination. The preliminary results show that the use of optimal illuminations improved the contrast of diabetic lesions in retinal images by 30-70%, compared to the traditional red-free illumination imaging.

  12. Comparison of image reconstruction methods for structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Lukeš, Tomas; Hagen, Guy M.; Křížek, Pavel; Švindrych, Zdeněk.; Fliegel, Karel; Klíma, Miloš

    2014-05-01

    Structured illumination microscopy (SIM) is a recent microscopy technique that enables one to go beyond the diffraction limit using patterned illumination. The high frequency information is encoded through aliasing into the observed image. By acquiring multiple images with different illumination patterns aliased components can be separated and a highresolution image reconstructed. Here we investigate image processing methods that perform the task of high-resolution image reconstruction, namely square-law detection, scaled subtraction, super-resolution SIM (SR-SIM), and Bayesian estimation. The optical sectioning and lateral resolution improvement abilities of these algorithms were tested under various noise level conditions on simulated data and on fluorescence microscopy images of a pollen grain test sample and of a cultured cell stained for the actin cytoskeleton. In order to compare the performance of the algorithms, the following objective criteria were evaluated: Signal to Noise Ratio (SNR), Signal to Background Ratio (SBR), circular average of the power spectral density and the S3 sharpness index. The results show that SR-SIM and Bayesian estimation combine illumination patterned images more effectively and provide better lateral resolution in exchange for more complex image processing. SR-SIM requires one to precisely shift the separated spectral components to their proper positions in reciprocal space. High noise levels in the raw data can cause inaccuracies in the shifts of the spectral components which degrade the super-resolved image. Bayesian estimation has proven to be more robust to changes in noise level and illumination pattern frequency.

  13. Color constancy supports cross-illumination color selection

    PubMed Central

    Radonjić, Ana; Cottaris, Nicolas P.; Brainard, David H.

    2015-01-01

    We rely on color to select objects as the targets of our actions (e.g., the freshest fish, the ripest fruit). To be useful for selection, color must provide accurate guidance about object identity across changes in illumination. Although the visual system partially stabilizes object color appearance across illumination changes, how such color constancy supports object selection is not understood. To study how constancy operates in real-life tasks, we developed a novel paradigm in which subjects selected which of two test objects presented under a test illumination appeared closer in color to a target object presented under a standard illumination. From subjects' choices, we inferred a selection-based match for the target via a variant of maximum likelihood difference scaling, and used it to quantify constancy. Selection-based constancy was good when measured using naturalistic stimuli, but was dramatically reduced when the stimuli were simplified, indicating that a naturalistic stimulus context is critical for good constancy. Overall, our results suggest that color supports accurate object selection across illumination changes when both stimuli and task match how color is used in real life. We compared our selection-based constancy results with data obtained using a classic asymmetric matching task and found that the adjustment-based matches predicted selection well for our stimuli and instructions, indicating that the appearance literature provides useful guidance for the emerging study of constancy in natural tasks. PMID:26024460

  14. Photobioreactors with internal illumination - A survey and comparison.

    PubMed

    Heining, Martin; Buchholz, Rainer

    2015-08-01

    The idea of internally illuminated photobioreactors has existed since the 1990s and various systems were developed since. Recently, the interest in these systems has been on the rise again, due to the increased production of and research on high-value products and recombinant proteins from microalgae and plant cell cultures. While promising results in lab-scale have been achieved, the potential of photoautotrophic or mixotrophic production of these compounds is limited due to the lack of scalable photobioreactors, which could be overcome by internally illuminated systems. In this article, we review different internally illuminated photobioreactors from the last two decades and classify them into two major groups. The photobioreactors are compared based on the ratio of illuminated surface-to-culture volume and the occupied volume by internal light-emitting elements, and possible obstacles, challenges and future trends are discussed. Looking forward, new technologies and smaller light sources have improved the potential of internally illuminated photobioreactors with internal light sources and will enable these technologies to compete with systems with internal light guides, but only a few of these systems have currently achieved a relevant scale.

  15. Adaptive optimisation of illumination beam profiles in fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Mitchell, T. J.; Saunter, C. D.; O'Nions, W.; Girkin, J. M.; Love, G. D.

    2015-03-01

    Wide-field fluorescence microscope techniques such as single/selective plane illumination microscope (SPIM) are typically configured to image large regions of a sample at once. Here the illumination beam provides uniform excitation of several biological features across the region, `sliced' to a thickness of between 5-10 microns. In this paper we propose a simple alteration to the optical configuration of a SPIM by switching the light-sheet- forming cylindrical lens with a spatial light modulator. This has the potential to adaptively reconfigure the light sheet geometry to improve the optical sectioning of specific biological features, rather than the thicker sectioning of several features at once across a larger observation field-of-view. We present a prototype version of such a system, referred to as an Adaptive-SPIM (A-SPIM) system. We then suggest that the direct recording of illumination beam shapes within the working microscope system can better facilitate the analysis and subsequent re-configuration of the illumination beam to a specific geometry, and summarise the design and operation of a device that we have developed specifically for this purpose. We finally present reconstructed quantitative three dimensional flux maps of illumination beams from three microscope configurations taken using this miniature high-dynamic range beam profiling device, comparing the beam geometry of a regular SPIM system with our prototype A-SPIM system, and suggesting future improvements.

  16. Constrained low-rank gamut completion for robust illumination estimation

    NASA Astrophysics Data System (ADS)

    Zhou, Jianshen; Yuan, Jiazheng; Liu, Hongzhe

    2017-02-01

    Illumination estimation is an important component of color constancy and automatic white balancing. According to recent survey and evaluation work, the supervised methods with a learning phase are competitive for illumination estimation. However, the robustness and performance of any supervised algorithm suffer from an incomplete gamut in training image sets because of limited reflectance surfaces in a scene. In order to address this problem, we present a constrained low-rank gamut completion algorithm, which can replenish gamut from limited surfaces in an image, for robust illumination estimation. In the proposed algorithm, we first discuss why the gamut completion is actually a low-rank matrix completion problem. Then a constrained low-rank matrix completion framework is proposed by adding illumination similarities among the training images as an additional constraint. An optimization algorithm is also given out by extending the augmented Lagrange multipliers. Finally, the completed gamut based on the proposed algorithm is fed into the support vector regression (SVR)-based illumination estimation method to evaluate the effect of gamut completion. The experimental results on both synthetic and real-world image sets show that the proposed gamut completion model not only can effectively improve the performance of the original SVR method but is also robust to the surface insufficiency in training samples.

  17. Characterization of Lunar Polar Illumination from a Power System Perspective

    NASA Technical Reports Server (NTRS)

    Fincannon, James

    2008-01-01

    This paper presents the results of illumination analyses for the lunar south and north pole regions obtained using an independently developed analytical tool and two types of digital elevation models (DEM). One DEM was based on radar height data from Earth observations of the lunar surface and the other was a combination of the radar data with a separate dataset generated using Clementine spacecraft stereo imagery. The analysis tool enables the assessment of illumination at most locations in the lunar polar regions for any time and any year. Maps are presented for both lunar poles for the worst case winter period (the critical power system design and planning bottleneck) and for the more favorable best case summer period. Average illumination maps are presented to help understand general topographic trends over the regions. Energy storage duration maps are presented to assist in power system design. Average illumination fraction, energy storage duration, solar/horizon terrain elevation profiles and illumination fraction profiles are presented for favorable lunar north and south pole sites which have the potential for manned or unmanned spacecraft operations. The format of the data is oriented for use by power system designers to develop mass optimized solar and energy storage systems.

  18. Micromilled optical elements for edge-lit illumination panels

    NASA Astrophysics Data System (ADS)

    Ronny, Rahima Afrose; Knopf, George K.; Bordatchev, Evgueni; Nikumb, Suwas

    2013-04-01

    Edge-lit light guide panels (LGPs) with micropatterned surfaces represent a new technology for developing small- and medium-sized illumination sources for application such as automotive, residential lighting, and advertising displays. The shape, density, and spatial distribution of the micro-optical structures (MOSs) imprinted on the transparent LGP must be selected to achieve high brightness and uniform luminance over the active surface. We examine how round-tip cylindrical MOSs fabricated by precision micromilling can be used to create patterned surfaces on low-cost transparent polymethyl-methacrylate substrates for high-intensity illumination applications. The impact of varying the number, pitch, spatial distribution, and depth of the optical microstructures on lighting performance is initially investigated using LightTools™ simulation software. To illustrate the microfabrication process, several 100×100×6 mm3 LGP prototypes are constructed and tested. The prototypes include an "optimized" array of MOSs that exhibit near-uniform illumination (approximately 89%) across its active light-emitting surface. Although the average illumination was 7.3% less than the value predicted from numerical simulation, it demonstrates how LGPs can be created using micromilling operations. Customized MOS arrays with a bright rectangular pattern near the center of the panel and a sequence of MOSs that illuminate a predefined logo are also presented.

  19. Low-resolution face tracker robust to illumination variations.

    PubMed

    Zou, Wilman W; Yuen, Pong C; Chellappa, Rama

    2013-05-01

    In many practical video surveillance applications, the faces acquired by outdoor cameras are of low resolution and are affected by uncontrolled illumination. Although significant efforts have been made to facilitate face tracking or illumination normalization in unconstrained videos, the approaches developed may not be effective in video surveillance applications. This is because: 1) a low-resolution face contains limited information, and 2) major changes in illumination on a small region of the face make the tracking ineffective. To overcome this problem, this paper proposes to perform tracking in an illumination-insensitive feature space, called the gradient logarithm field (GLF) feature space. The GLF feature mainly depends on the intrinsic characteristics of a face and is only marginally affected by the lighting source. In addition, the GLF feature is a global feature and does not depend on a specific face model, and thus is effective in tracking low-resolution faces. Experimental results show that the proposed GLF-based tracker works well under significant illumination changes and outperforms many state-of-the-art tracking algorithms.

  20. The evolution of structured illumination microscopy in studies of HIV.

    PubMed

    Marno, Kelly; Al'Zoubi, Lara; Pearson, Matthew; Posch, Markus; McKnight, Áine; Wheeler, Ann P

    2015-10-15

    The resolution limit of conventional light microscopy has proven to be limiting for many biological structures such as viruses including Human immunodeficiency virus (HIV). Individual HIV virions are impossible to study using confocal microscopy as they are well below the 200 nm resolution limit of conventional light microscopes. Structured illumination microscopy (SIM) allows a twofold enhancement in image resolution compared to standard widefield illumination and so provides an excellent tool for study of HIV. Viral capsids (CAs) vary between 110 and 146 nm so this study challenges the performance of SIM microscopes. SIM microscopy was first developed in 2000, commercialised in 2007 and rapidly developed. Here we present the changes in capabilities of the SIM microscopes for study of HIV localisation as the instrumentation for structured illumination microscopy has evolved over the past 8 years.

  1. Object tracking under nonuniform illumination with adaptive correlation filtering

    NASA Astrophysics Data System (ADS)

    Picos, Kenia; Díaz-Ramírez, Víctor H.; Kober, Vitaly

    2013-09-01

    A real-time system for illumination-invariant object tracking is proposed. The system is able to estimate at high-rate the position of a moving target in an input scene when is corrupted by the presence of a high cluttering background and nonuniform illumination. The position of the target is estimated with the help of a filter bank of space-variant correlation filters. The filters in the bank, adapt their parameters according to the local statistical parameters of the observed scene in a small region centered at coordinates of a predicted position for the target in each frame. The prediction is carried out by exploiting information of present and past frames, and by using a dynamic motion model of the target in a two-dimensional plane. Computer simulation results obtained with the proposed system are presented and discussed in terms of tracking accuracy, computational complexity, and tolerance to nonuniform illumination.

  2. Structured illumination microscopy with unknown patterns and a statistical prior

    PubMed Central

    Yeh, Li-Hao; Tian, Lei; Waller, Laura

    2017-01-01

    Structured illumination microscopy (SIM) improves resolution by down-modulating high-frequency information of an object to fit within the passband of the optical system. Generally, the reconstruction process requires prior knowledge of the illumination patterns, which implies a well-calibrated and aberration-free system. Here, we propose a new algorithmic self-calibration strategy for SIM that does not need to know the exact patterns a priori, but only their covariance. The algorithm, termed PE-SIMS, includes a pattern-estimation (PE) step requiring the uniformity of the sum of the illumination patterns and a SIM reconstruction procedure using a statistical prior (SIMS). Additionally, we perform a pixel reassignment process (SIMS-PR) to enhance the reconstruction quality. We achieve 2× better resolution than a conventional widefield microscope, while remaining insensitive to aberration-induced pattern distortion and robust against parameter tuning. PMID:28270977

  3. Local feature descriptor invariant to monotonic illumination changes

    NASA Astrophysics Data System (ADS)

    Yan, Pu; Liang, Dong; Tang, Jun; Zhu, Ming

    2016-01-01

    This paper presents a monotonic invariant intensity descriptor (MIID) via spectral embedding and nonsubsampled contourlet transform (NSCT). To make the proposed descriptor discriminative, NSCT is used for the construction of multiple support regions. Specifically, the directed graph and the spectral feature vectors of the signless Laplacian matrix are exploited to construct the MIID. We theoretically demonstrate that the proposed descriptor is able to tackle monotonic illumination changes and many other geometric and photometric transformations. We conduct extensive experiments on the standard Oxford dataset and the complex illumination dataset to demonstrate the superiority of proposed descriptor over the existing state-of-the-art descriptors in dealing with image blur, viewpoint changes, illumination changes, and JPEG compression.

  4. A back-illuminated megapixel CMOS image sensor

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Cunningham, Thomas; Nikzad, Shouleh; Hoenk, Michael; Jones, Todd; Wrigley, Chris; Hancock, Bruce

    2005-01-01

    In this paper, we present the test and characterization results for a back-illuminated megapixel CMOS imager. The imager pixel consists of a standard junction photodiode coupled to a three transistor-per-pixel switched source-follower readout [1]. The imager also consists of integrated timing and control and bias generation circuits, and provides analog output. The analog column-scan circuits were implemented in such a way that the imager could be configured to run in off-chip correlated double-sampling (CDS) mode. The imager was originally designed for normal front-illuminated operation, and was fabricated in a commercially available 0.5 pn triple-metal CMOS-imager compatible process. For backside illumination, the imager was thinned by etching away the substrate was etched away in a post-fabrication processing step.

  5. Holographic illuminator for synchrotron-based projection lithography systems

    DOEpatents

    Naulleau, Patrick P.

    2005-08-09

    The effective coherence of a synchrotron beam line can be tailored to projection lithography requirements by employing a moving holographic diffuser and a stationary low-cost spherical mirror. The invention is particularly suited for use in an illuminator device for an optical image processing system requiring partially coherent illumination. The illuminator includes: (1) a synchrotron source of coherent or partially coherent radiation which has an intrinsic coherence that is higher than the desired coherence, (2) a holographic diffuser having a surface that receives incident radiation from said source, (3) means for translating the surface of the holographic diffuser in two dimensions along a plane that is parallel to the surface of the holographic diffuser wherein the rate of the motion is fast relative to integration time of said image processing system; and (4) a condenser optic that re-images the surface of the holographic diffuser to the entrance plane of said image processing system.

  6. Local and Global Illumination in the Volume Rendering Integral

    SciTech Connect

    Max, N; Chen, M

    2005-10-21

    This article is intended as an update of the major survey by Max [1] on optical models for direct volume rendering. It provides a brief overview of the subject scope covered by [1], and brings recent developments, such as new shadow algorithms and refraction rendering, into the perspective. In particular, we examine three fundamentals aspects of direct volume rendering, namely the volume rendering integral, local illumination models and global illumination models, in a wavelength-independent manner. We review the developments on spectral volume rendering, in which visible light are considered as a form of electromagnetic radiation, optical models are implemented in conjunction with representations of spectral power distribution. This survey can provide a basis for, and encourage, new efforts for developing and using complex illumination models to achieve better realism and perception through optical correctness.

  7. Optimizing ultrafast illumination for multiphoton-excited fluorescence imaging

    PubMed Central

    Stoltzfus, Caleb R.; Rebane, Aleksander

    2016-01-01

    We study the optimal conditions for high throughput two-photon excited fluorescence (2PEF) and three-photon excited fluorescence (3PEF) imaging using femtosecond lasers. We derive relations that allow maximization of the rate of imaging depending on the average power, pulse repetition rate, and noise characteristics of the laser, as well as on the size and structure of the sample. We perform our analysis using ~100 MHz, ~1 MHz and 1 kHz pulse rates and using both a tightly-focused illumination beam with diffraction-limited image resolution, as well loosely focused illumination with a relatively low image resolution, where the latter utilizes separate illumination and fluorescence detection beam paths. Our theoretical estimates agree with the experiments, which makes our approach especially useful for optimizing high throughput imaging of large samples with a field-of-view up to 10x10 cm2. PMID:27231620

  8. On illumination schemes for wide-field CARS microscopy.

    PubMed

    Toytman, I; Simanovskii, D; Palanker, D

    2009-04-27

    New system for a wide-field CARS microscopy is demonstrated, including two schemes of non-phase-matching illumination. Several advantages including high Stokes pulse energy, pulse-to-pulse stability and inherent synchronization between pump and Stokes pulses were brought by use of methane-filled Raman converter. Spatial resolution of the system with axially symmetric illumination, 0.5 microm, was found to correspond to diffraction limit of the imaging objective. Selective sensitivity to lipid-rich myelin sheaths in the nerve tissue has been demonstrated and confirmed by comparison with histological samples stained with myelin-specific dye. Single-shot imaging capability of the system has been demonstrated with a speckling-free illumination on a monolayer of 3 microm polystyrene beads.

  9. Planetary science: constant illumination at the lunar north pole.

    PubMed

    Bussey, D Ben J; Fristad, Kirsten E; Schenk, Paul M; Robinson, Mark S; Spudis, Paul D

    2005-04-14

    Images returned by the spacecraft Clementine have been used to produce a quantitative illumination map of the north pole of the Moon, revealing the percentage of time that points on the surface are illuminated during the lunar day. We have used this map to identify areas that are constantly illuminated during a lunar day in summer and which may therefore be in permanent sunlight. All are located on the northern rim of Peary crater, close to the north pole. Permanently sunlit areas represent prime locations for lunar outpost sites as they have abundant solar energy, are relatively benign thermally (when compared with equatorial regions), and are close to permanently shadowed regions that may contain water ice.

  10. On the relation between zenith sky brightness and horizontal illuminance

    NASA Astrophysics Data System (ADS)

    Kocifaj, M.; Posch, Th.; Solano Lamphar, H. A.

    2015-01-01

    The effects of artificial light at night are an emergent research topic for astronomers, physicists, engineers and biologists around the world. This leads to a need for measurements of the night sky brightness (= diffuse luminance of the night sky) and nocturnal illuminance. Currently, the most sensitive light meters measure the zenith sky brightness in magV/arcsec2 or - less frequently - in cd m-2. However, the horizontal illuminance resulting only from the night sky is an important source of information that is difficult to obtain with common instruments. Here we present a set of approximations to convert the zenith luminance into horizontal illuminance. Three different approximations are presented for three idealized atmospheric conditions: homogeneous sky brightness, an isotropically scattering atmosphere and a turbid atmosphere. We also apply the resulting conversion formulae to experimental data on night sky luminance, obtained during the past three years.

  11. Illumination-parameter adjustable and illumination-distribution visible LED helmet for low-level light therapy on brain injury

    NASA Astrophysics Data System (ADS)

    Wang, Pengbo; Gao, Yuan; Chen, Xiao; Li, Ting

    2016-03-01

    Low-level light therapy (LLLT) has been clinically applied. Recently, more and more cases are reported with positive therapeutic effect by using transcranial light emitting diodes (LEDs) illumination. Here, we developed a LLLT helmet for treating brain injuries based on LED arrays. We designed the LED arrays in circle shape and assembled them in multilayered 3D printed helmet with water-cooling module. The LED arrays can be adjust to touch the head of subjects. A control circuit was developed to drive and control the illumination of the LLLT helmet. The software portion provides the control of on and off of each LED arrays, the setup of illumination parameters, and 3D distribution of LLLT light dose in human subject according to the illumination setups. This LLLT light dose distribution was computed by a Monte Carlo model for voxelized media and the Visible Chinese Human head dataset and displayed in 3D view at the background of head anatomical structure. The performance of the whole system was fully tested. One stroke patient was recruited in the preliminary LLLT experiment and the following neuropsychological testing showed obvious improvement in memory and executive functioning. This clinical case suggested the potential of this Illumination-parameter adjustable and illuminationdistribution visible LED helmet as a reliable, noninvasive, and effective tool in treating brain injuries.

  12. Fundus spectroscopy and studies in retinal oximetry using intravitreal illumination

    NASA Astrophysics Data System (ADS)

    Salyer, David Alan

    This dissertation documents the development of a new illumination technique for use in the studies of retinal oximetry and fundus spectroscopy. Intravitreal illumination is a technique where the back of the eye is illuminated trans-sclerally using a scanning monochromator coupled into a fiber optic illuminator. Retinal oximetry is the process of measuring the oxygen saturation of blood contained in retinal vessels by quantitative measurement of the characteristic color shift seen as blood oxygen saturation changes from oxygenated blood (reddish) to deoxygenated blood (bluish). Retinal oximetry was first attempted in 1963 but due to a variety of problems with accuracy and difficulty of measurement, has not matured to the point of clinical acceptability or commercial viability. Accurate retinal oximetry relies in part on an adequate understanding of the spectral reflectance characteristics of the fundus. The use of intravitreal illumination allows new investigations into the spectral reflectance properties of the fundus. The results of much research in fundus reflectance and retinal oximetry is detailed in this document, providing new insight into both of these related fields of study. Intravitreal illumination has been used to study retinal vessel oximetry and fundus reflectometry resulting in several important findings that are presented in this document. Studies on enucleated swine eyes have provided new insight into the bidirectional reflectance distribution function of the fundus. Research on live swine has shown accurate measurement of retinal vessel oxygen saturation and provided the first in vivo spectral transmittance measurement of the sensory retina. A secondary discovery during this research suggests that vitrectomy alters the retinal vasculature, an finding that should spawn new research in its own right.

  13. Three-dimensional illumination procedure for photodynamic therapy of dermatology

    NASA Astrophysics Data System (ADS)

    Hu, Xiao-ming; Zhang, Feng-juan; Dong, Fei; Zhou, Ya

    2014-09-01

    Light dosimetry is an important parameter that affects the efficacy of photodynamic therapy (PDT). However, the irregular morphologies of lesions complicate lesion segmentation and light irradiance adjustment. Therefore, this study developed an illumination demo system comprising a camera, a digital projector, and a computing unit to solve these problems. A three-dimensional model of a lesion was reconstructed using the developed system. Hierarchical segmentation was achieved with the superpixel algorithm. The expected light dosimetry on the targeted lesion was achieved with the proposed illumination procedure. Accurate control and optimization of light delivery can improve the efficacy of PDT.

  14. Structured illumination microscopy of autofluorescent aggregations in human tissue.

    PubMed

    Best, Gerrit; Amberger, Roman; Baddeley, David; Ach, Thomas; Dithmar, Stefan; Heintzmann, Rainer; Cremer, Christoph

    2011-06-01

    Sections from human eye tissue were analyzed with Structured Illumination Microscopy (SIM) using a specially designed microscope setup. In this microscope the structured illumination was generated with a Twyman-Green Interferometer. This SIM technique allowed us to acquire light-optical images of autofluorophore distributions in the tissue with previously unmatched optical resolution. In this work the unique setup of the microscope made possible the application of SIM with three different excitation wavelengths (488, 568 and 647 nm), thus enabling us to gather spectral information about the autofluorescence signal.

  15. Illumination, wavelength selection, and detection in fluorescence microscopy.

    PubMed

    Spring, K R

    1991-07-01

    The presently available devices for the illumination, changing of wavelengths, and detection of the resultant fluorescence of biological samples viewed in the light microscope have been described and compared. The optimal choice for illumination is a xenon arc lamp with a filter wheel wavelength selector. The optimal choice for an imaging detector is an intensified CCD (charge-coupled-device) camera. These combinations produce the most rapid, stable, and reproducible results when fluorescence measurements are made on living epithelial cells or isolated renal tubules. Techniques for the simultaneous acquisition of fluorescence and differential interference contrast (DIC) images have also been described and compared.

  16. Infrared laser diode with visible illuminator for biomedical stimulation

    NASA Astrophysics Data System (ADS)

    Strek, Wieslaw; Podbielska, Halina; Szafranski, C.; Kuzmin, Andrei N.; Ges, J. A.; Ryabtsev, Gennadii I.

    1995-02-01

    The special laser diode device (LDD) leasing in the near infrared region (IR) with two wavelengths: (lambda) 1 equals 850 nm and (lambda) 2 equals 1000 nm, designed for laser therapy, is presented. This device is characterized by a unique feature, namely a separate built-in illuminator, operating in 670 nm. The special construction of LDD and the illuminator enables the user to visualize exactly the surface irradiated by IR radiation. The exposure time and the output of laser power are also controlled and can be displayed on the LED monitor at the front panel. This new device, described here, is compact, low cost, and user friendly.

  17. High efficiency source coupler for optical waveguide illumination system

    DOEpatents

    Siminovitch, Michael J.

    2000-01-01

    A fiber optic or optical waveguide illumination system includes a source coupling system. The source coupling system includes an optical channel with an internal cavity. A light source is disposed inside the driving circuit. Coupling losses are minimized by placing the light source within the optical channel. The source cavity and the source optical channel can be shaped to enhance the amount of light captured in the channel by total internal reflection. Multiple light distribution waveguides can be connected to the source coupling channel to produce an illumination system.

  18. Extraterrestrial applications of solar optics for interior illumination

    NASA Technical Reports Server (NTRS)

    Eijadi, David A.; Williams, Kyle D.

    1992-01-01

    Solar optics is a terrestrial technology that has potential extraterrestrial applications. Active solar optics (ASO) and passive solar optics (PSO) are two approaches to the transmission of sunlight to remote interior spaces. Active solar optics is most appropriate for task illumination, while PSO is most appropriate for general illumination. Research into solar optics, motivated by energy conservation, has produced lightweight and low-cost materials, products that have applications to NASA's Controlled Ecological Life Support System (CELSS) program and its lunar base studies. Specifically, prism light guides have great potential in these contexts. Several applications of solar optics to lunar base concepts are illustrated.

  19. Near-field enhanced Raman spectroscopy using side illumination optics

    NASA Astrophysics Data System (ADS)

    Hayazawa, Norihiko; Tarun, Alvarado; Inouye, Yasushi; Kawata, Satoshi

    2002-12-01

    We demonstrate near-field enhanced Raman spectroscopy with the use of a metallized cantilever tip and highly p-polarized light directed onto the tip with side illumination optics using a long working distance objective lens. The highly p-polarized light field excites surface plasmon polaritons localized at the tip apex, which results in the enhanced near-field Raman scattering. In this article, we achieved an enhancement factor of 4000 for Rhodamine 6G molecules adsorbed on a silver island film. The side illumination is also applicable to an opaque sample and to near-field photolithography.

  20. Microwave holographic imaging of aircraft with spaceborne illuminating source

    NASA Technical Reports Server (NTRS)

    Berkowitz, R. S.; Dzekov, T. A.

    1976-01-01

    The conceptual development of a method for the high angular resolution and accurate angular position estimates for the surveillance and traffic control of aircraft is considered. A target volume several hundred kilometers in diameter is illuminated by a CW microwave source located on a satellite in geosynchronous orbit. Signals are received by a large array of random, conformally located receiving elements. Each element receives the direct signal from the satellite plus signals reflected from aircraft in the illuminated volume. Coherent combination of the signals received from the individual elements permits the equivalent of holographic imaging or multiple beam formation from which the useful target data can be obtained.

  1. Illumination-based synchronization of high-speed vision sensors.

    PubMed

    Hou, Lei; Kagami, Shingo; Hashimoto, Koichi

    2010-01-01

    To acquire images of dynamic scenes from multiple points of view simultaneously, the acquisition time of vision sensors should be synchronized. This paper describes an illumination-based synchronization method derived from the phase-locked loop (PLL) algorithm. Incident light to a vision sensor from an intensity-modulated illumination source serves as the reference signal for synchronization. Analog and digital computation within the vision sensor forms a PLL to regulate the output signal, which corresponds to the vision frame timing, to be synchronized with the reference. Simulated and experimental results show that a 1,000 Hz frame rate vision sensor was successfully synchronized with 32 μs jitters.

  2. 3D Imaging with Structured Illumination for Advanced Security Applications

    SciTech Connect

    Birch, Gabriel Carisle; Dagel, Amber Lynn; Kast, Brian A.; Smith, Collin S.

    2015-09-01

    Three-dimensional (3D) information in a physical security system is a highly useful dis- criminator. The two-dimensional data from an imaging systems fails to provide target dis- tance and three-dimensional motion vector, which can be used to reduce nuisance alarm rates and increase system effectiveness. However, 3D imaging devices designed primarily for use in physical security systems are uncommon. This report discusses an architecture favorable to physical security systems; an inexpensive snapshot 3D imaging system utilizing a simple illumination system. The method of acquiring 3D data, tests to understand illumination de- sign, and software modifications possible to maximize information gathering capability are discussed.

  3. The possible ocular hazards of LED dental illumination applications.

    PubMed

    Stamatacos, Catherine; Harrison, Janet L

    2013-01-01

    The use of high-intensity illumination via Light-Emitting Diode (LED) headlamps is gaining in popularity with dentists and student dentists. Practitioners are using LED headlamps together with magnifying loupes, overhead LED illumination and fiber-optic dental handpieces for long periods of time. Although most manufacturers of these LED illuminators advertise that their devices emit "white" light, these still consist of two spectral bands--the blue spectral band, with its peak at 445 nm, and the green with its peak at 555 nm. While manufacturers suggest that their devices emit "white" light, spectral components of LED lights from different companies are significantly different. Dental headlamp manufacturers strive to create a white LED, and they advertise that this type of light emitted from their product offers bright white-light illumination. However, the manufacturing of a white LED light is done through selection of a white LED-type based on the peak blue strength in combination with the green peak strength and thus creating a beam-forming optic, which determines the beam quality. Some LED illuminators have a strong blue-light component versus the green-light component. Blue-light is highly energized and is close in the color spectrum to ultraviolet-light. The hazards of retinal damage with the use of high-intensity blue-lights has been well-documented. There is limited research regarding the possible ocular hazards of usage of high-intensity illuminating LED devices. Furthermore, the authors have found little research, standards, or guidelines examining the possible safety issues regarding the unique dental practice setting consisting of the combined use of LED illumination systems. Another unexamined component is the effect of high-intensity light reflective glare and magnification back to the practitioner's eyes due to the use of water during dental procedures. Based on the result of Dr. Janet Harrison's observations of beginning dental students in a

  4. The possible ocular hazards of LED dental illumination applications.

    PubMed

    Stamatacos, Catherine; Harrison, Janet L

    2014-04-01

    The use of high-intensity illumination via Light-Emitting Diode (LED) headlamps is gaining in popularity with dentists and student dentists. Practitioners are using LED headlamps together with magnifying loupes, overhead LED illumination and fiber-optic dental handpieces for long periods of time. Although most manufacturers of these LED illuminators advertise that their devices emit "white" light, these still consist of two spectral bands - the blue spectral band, with its peak at 445 nm, and the green with its peak at 555 nm. While manufacturers suggest that their devices emit "white" light, spectral components of LED lights from different companies are significantly different. Dental headlamp manufacturers strive to create a white LED, and they advertise that this type of light emitted from their product offers bright white-light illumination. However, the manufacturing of a white LED light is done through selection of a white LED-type based on the peak blue strength in combination with the green peak strength and thus creating a beam-forming optic, which determines the beam quality. Some LED illuminators have a strong blue-light component versus the green-light component. Blue-light is highly energized and is close in the color spectrum to ultraviolet-light. The hazards of retinal damage with the use of high-intensity blue-lights has been well-documented. There is limited research regarding the possible ocular hazards of usage of high-intensity illuminating LED devices. Furthermore, the authors have found little research, standards, or guidelines examining the possible safety issues regarding the unique dental practice setting consisting of the combined use of LED illumination systems. Another unexamined component is the effect of high-intensity light reflective glare and magnification back to the practitioner's eyes due to the use of water during dental procedures. Based on the result of Dr. Janet Harrison's observations of beginning dental students in a

  5. Simulation and comparison of the illuminance, uniformity, and efficiency of different forms of lighting used in basketball court illumination.

    PubMed

    Sun, Wen-Shing; Tien, Chuen-Lin; Tsuei, Chih-Hsuan; Pan, Jui-Wen

    2014-10-10

    We simulate and compare the illuminance, uniformity, and efficiency of metal-halide lamps, white LED light sources, and hybrid light box designs combining sunlight and white LED lighting used for indoor basketball court illumination. According to the optical simulation results and our examination of real situations, we find that hybrid light box designs combining sunlight and white LEDs do perform better than either metal-halide lamps or white LED lights. An evaluation of the sunlight concentrator system used in our inverted solar cell shows that the energy consumption of stadium lighting can be reduced significantly.

  6. Uneven illumination removal and image enhancement using empirical mode decomposition

    NASA Astrophysics Data System (ADS)

    Pei, Soo-Chang; Hsiao, Yu-Zhe; Tzeng, Mary; Chang, Feng Ju

    2013-10-01

    Uneven light distribution problems often arise in poorly scanned text or text-photo images and natural images taken by digital camera. An innovative image-processing technique for uneven illumination removal using empirical mode decomposition (EMD) is proposed. The EMD is local, adaptive, and useful for analyzing nonlinear and nonstationary signals. In this method, we decompose images by EMD and get the background level locally and adaptively. This algorithm can enhance the local reflectance in the image while removing uneven illumination for black/white text images, text-photo images, and natural color/gray-level images. The proposed technique can be very helpful for image and text recognition. The EMD can also be applied to the three color channels (RGB) of color images separately to estimate the reflectances of the three color channels. After we relight these channels using white light and the estimated reflectances, a simple color constancy task can be performed to correct certain poorly lighted color images. Our technique is compared with recently proposed methods for correcting images with uneven illumination and the experimental results demonstrated that the proposed approach can effectively enhance natural color/gray-level images and make text and text-photo images more readable under uneven illumination.

  7. Fully depleted back-illuminated p-channel CCD development

    SciTech Connect

    Bebek, Chris J.; Bercovitz, John H.; Groom, Donald E.; Holland, Stephen E.; Kadel, Richard W.; Karcher, Armin; Kolbe, William F.; Oluseyi, Hakeem M.; Palaio, Nicholas P.; Prasad, Val; Turko, Bojan T.; Wang, Guobin

    2003-07-08

    An overview of CCD development efforts at Lawrence Berkeley National Laboratory is presented. Operation of fully-depleted, back-illuminated CCD's fabricated on high resistivity silicon is described, along with results on the use of such CCD's at ground-based observatories. Radiation damage and point-spread function measurements are described, as well as discussion of CCD fabrication technologies.

  8. Illumination design for semiconductor backlight inspection and application extensions

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Rutherford, Todd; Hart, Darcy

    2013-09-01

    High speed strobe based illumination scheme is one of the most critical factors for high throughput semiconductor defect inspection applications. HB LEDs are always the first and best options for such applications due to numerous unique advantages such as excellent spatial and temporal stability, fast responding time, large and linear intensity dynamic range and no heat issue for the extremely low duty cycle applications. For some applications where a large area is required to be illuminated simultaneously, it remains a great challenge to efficiently package a large amount of HB-LEDs in a highly confined 3D space, to generate a seamless illuminated area with high luminance efficiency and spatial uniformity. A novel 3D structured collimation lens is presented in this paper. The non-circular edge shape reduces the intensity drop at the channel boundaries, while the secondary curvatures on the top of the collimator lens efficiently guides the light into desired angular space. The number of the edges and the radius of the top surface curvature are control parameters for the system level performance and the manufacture cost trade-off. The proposed 3D structured LED collimation lens also maintains the benefits of traditional LED collimation lens such as coupling efficiency and mold manufacture capability. The applications can be extended into other non-illumination area like parallelism measurement and solar panel concentrator etc.

  9. Studies in Natural Illumination in Schoolrooms. Part III

    DTIC Science & Technology

    1929-11-01

    PI"C HEALTH BULLIN No. 188 STUDIESJIN ATURA ILUMINATION IN SCHOOLROOMSA f1-~7~PART III 20 U. 0 49990809 433 UngimED STATES ý-REASURY DE~PART1WENT... ilumination ratio of desk No. 14 for each month and hour of observation ---------------------------------------------- 55 29. Mean illumination ratio of desk

  10. Illumination invariance and shadow compensation via spectro-polarimetry technique

    NASA Astrophysics Data System (ADS)

    Ibrahim, Izzati; Yuen, Peter; Hong, Kan; Chen, Tong; Soori, Umair; Jackman, James; Richardson, Mark

    2012-10-01

    A major problem for obtaining target reflectance via hyperspectral imaging systems is the presence of illumination and shadow effects. These factors are common artefacts, especially when dealing with a hyperspectral imaging system that has sensors in the visible to near infrared region. This region is known to have highly scattered and diffuse radiance that can modify the energy recorded by the imaging system. A shadow effect will lower the target reflectance values due to the small radiant energy impinging on the target surface. Combined with illumination artefacts, such as diffuse scattering from the surrounding targets, background or environment, the shape of the shadowed target reflectance will be altered. We propose a new method to compensate for illumination and shadow effects on hyperspectral imageries by using a polarization technique. This technique, called spectro-polarimetry, estimates the direct and diffuse irradiance based on two images taken with and without a polarizer. The method is then evaluated using a spectral similarity measure, angle and distance metric. The results of indoor and outdoor tests have shown that using the spectro-polarimetry technique can improve the spectral constancy between shadow and full illumination spectra.

  11. Apparatus and method for generating partially coherent illumination for photolithography

    DOEpatents

    Sweatt, William C.

    2001-01-01

    The present invention introduces a novel scatter plate into the optical path of source light used for illuminating a replicated object. The scatter plate has been designed to interrupt a focused, incoming light beam by introducing between about 8 to 24 diffraction zones blazed onto the surface of the scatter plate which intercept the light and redirect it to a like number of different positions in the condenser entrance pupil each of which is determined by the relative orientation and the spatial frequency of the diffraction grating in each of the several zones. Light falling onto the scatter plate, therefore, generates a plurality of unphased sources of illumination as seen by the back half of the optical system. The system comprises a high brightness source, such as a laser, creating light which is taken up by a beam forming optic which focuses the incoming light into a condenser which in turn, focuses light into a field lens creating Kohler illumination image of the source in a camera entrance pupil. The light passing through the field lens illuminates a mask which interrupts the source light as either a positive or negative image of the object to be replicated. Light passing by the mask is focused into the entrance pupil of the lithographic camera creating an image of the mask onto a receptive media.

  12. Improved forest change detection with terrain illumination corrected landsat images

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An illumination correction algorithm has been developed to improve the accuracy of forest change detection from Landsat reflectance data. This algorithm is based on an empirical rotation model and was tested on the Landsat imagery pair over Cherokee National Forest, Tennessee, Uinta-Wasatch-Cache N...

  13. Lensless phase microscopy using phase retrieval with multiple illumination wavelengths.

    PubMed

    Bao, Peng; Situ, Guohai; Pedrini, Giancarlo; Osten, Wolfgang

    2012-08-01

    A phase retrieval method for microscopy using multiple illumination wavelengths is proposed. A fast algorithm suitable for calculations with high numerical aperture is used for the iterative retrieval of the object wavefront. The advantages and limitations of the technique are systematically analyzed and demonstrated by both simulation and experimental results.

  14. Electrical Power and Illumination Systems. Energy Technology Series.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This course in electrical power and illumination systems is one of 16 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in…

  15. 10 CFR 431.202 - Definitions concerning illuminated exit signs.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Definitions concerning illuminated exit signs. 431.202 Section 431.202 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN... one manufacturer, having the same primary energy source, and which have essentially...

  16. 10 CFR 431.202 - Definitions concerning illuminated exit signs.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Definitions concerning illuminated exit signs. 431.202 Section 431.202 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN... one manufacturer, having the same primary energy source, and which have essentially...

  17. 10 CFR 431.202 - Definitions concerning illuminated exit signs.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Definitions concerning illuminated exit signs. 431.202 Section 431.202 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN... one manufacturer, having the same primary energy source, and which have essentially...

  18. Illuminating a Dialectical Transformative Activist Stance in Education

    ERIC Educational Resources Information Center

    Ritchie, Stephen M.

    2008-01-01

    In this essay I comment on Stetsenko's (2008) essay that draws together the work of Vygotsky, Piaget and Dewey, as she attempts to counter the "new" reductionist synthesis in public educational policy. While this theoretical work is helpful, it could be enhanced further by illuminating everyday practices of learners. I pose some questions that…

  19. 'Edge illumination' in X-ray Phase Contrast Imaging

    SciTech Connect

    Munro, Peter R. T.; Ignatyev, Konstantin; Diemoz, Paul C.; Szafraniec, Magdalena B.; Hagen, Charlotte K.; Millard, Thomas P.; Zapata, Cesar E.; Speller, Robert D.; Olivo, Alessandro

    2012-07-31

    In the late '90s, the concept of 'edge illumination' was developed at ELETTRA in Italy as an alternative method to increase the phase sensitivity of an imaging system. The main idea was to be able to reproduce the fine angular selection of 'analyzer' crystals without actually using a crystal, as this would allow employing the method with divergent and polychromatic (i.e. conventional) x-ray sources. It was observed that this could be achieved by illuminating only the edges of the detector pixels, and that the method's sensitivity could be progressively increased by illuminating smaller pixel fractions closer to its physical edge. A few years later the idea was adapted for use with a conventional source by means of two sets of x-ray masks ('coded aperture' masks), which enabled obtaining the same effect for each row (or column) of pixels of an area detector illuminated by a cone beam. This article reviews the method and presents recent examples of application.

  20. Colour constancy and conscious perception of changes of illuminant.

    PubMed

    Barbur, John L; Spang, Karoline

    2008-02-12

    A sudden change in illuminant (e.g., the outcome of turning on a tungsten light in a room illuminated with dim, natural daylight) causes a "global" change in perceived colour which subjects often recognise as a change of illuminant. In spite of this distinct, global change in the perceptual appearance of the scene caused by significant changes in the wavelength composition of the light reflected from different objects under the new illuminant, the perceived colour of the objects remains largely unchanged and this cornerstone property of human vision is often described as instantaneous colour constancy (ICC). ICC mechanisms are often difficult to study. The generation of appropriate stimuli to isolate ICC mechanisms remains a difficult task since the extraction of colour signals is also confounded in the processing of spatial chromatic context that leads to ICC. The extraction of differences in chromaticity that describe spatial changes in the wavelength composition of the light on the retina is a necessary operation that must precede colour constancy computations. A change of illuminant or changes in the spectral reflectance of the elements that make up the scene under a constant illuminant cause spatial changes in chromatic context and are likely to drive colour constancy mechanisms, but not exclusively. The same stimulus changes also cause differences in local luminance contrast and overall light flux changes, stimulus attributes that can activate different areas of the visual cortex. In order to address this problem we carried out a series of dichoptic experiments designed to investigate how the colour signals from the two eyes are combined in dichoptically viewed Mondrians and the extent to which the processing of chromatic context in monocularly driven neurons contributes to ICC. The psychophysical findings show that normal levels of ICC can be achieved in dichoptic experiments, even when the subject remains unaware of any changes of illuminant. Functional MRI

  1. Apparatus and method for generating partially coherent illumination for photolithography

    DOEpatents

    Sweatt, W.C.

    1999-07-06

    The present invention relates an apparatus and method for creating a bright, uniform source of partially coherent radiation for illuminating a pattern, in order to replicate an image of said pattern with a high degree of acuity. The present invention introduces a novel scatter plate into the optical path of source light used for illuminating a replicated object. The scatter plate has been designed to interrupt a focused, incoming light beam by introducing between about 8 to 24 diffraction zones blazed onto the surface of the scatter plate which intercept the light and redirect it to a like number of different positions in the condenser entrance pupil each of which is determined by the relative orientation and the spatial frequency of the diffraction grating in each of the several zones. Light falling onto the scatter plate, therefore, generates a plurality of unphased sources of illumination as seen by the back half of the optical system. The system includes a high brightness source, such as a laser, creating light which is taken up by a beam forming optic which focuses the incoming light into a condenser which in turn, focuses light into a field lens creating Kohler illumination image of the source in a camera entrance pupil. The light passing through the field lens illuminates a mask which interrupts the source light as either a positive or negative image of the object to be replicated. Light passing by the mask is focused into the entrance pupil of the lithographic camera creating an image of the mask onto a receptive media. 7 figs.

  2. Apparatus and method for generating partially coherent illumination for photolithography

    DOEpatents

    Sweatt, William C.

    1999-01-01

    The present invention relates an apparatus and method for creating a bright, uniform source of partially coherent radiation for illuminating a pattern, in order to replicate an image of said pattern with a high degree of acuity. The present invention introduces a novel scatter plate into the optical path of source light used for illuminating a replicated object. The scatter plate has been designed to interrupt a focused, incoming light beam by introducing between about 8 to 24 diffraction zones blazed onto the surface of the scatter plate which intercept the light and redirect it to a like number of different positions in the condenser entrance pupil each of which is determined by the relative orientation and the spatial frequency of the diffraction grating in each of the several zones. Light falling onto the scatter plate, therefore, generates a plurality of unphased sources of illumination as seen by the back half of the optical system. The system includes a high brightness source, such as a laser, creating light which is taken up by a beam forming optic which focuses the incoming light into a condenser which in turn, focuses light into a field lens creating Kohler illumination image of the source in a camera entrance pupil. The light passing through the field lens illuminates a mask which interrupts the source light as either a positive or negative image of the object to be replicated. Light passing by the mask is focused into the entrance pupil of the lithographic camera creating an image of the mask onto a receptive media.

  3. Formation of Singlet Molecular Oxygen on Illuminated Ice and Snow

    NASA Astrophysics Data System (ADS)

    McKellar, S. R.; Anastasio, C.

    2005-12-01

    Pollutants and other trace compounds on snow and ice are transformed both by direct photolysis as well as indirect photoreactions mediated by oxidants such as hydroxyl radical (OH). These reactions likely play a major role in the fate of environmental contaminants in regions with permanent or seasonal snow cover, but we know relatively little about which reactions are important and at what rates they transform trace pollutants. The indirect photodegradation of organics is most likely caused by oxidants such as OH and singlet molecular oxygen (1O2* ), which can be formed in the snowpack by illumination from the sun. While some recent work has characterized the formation of OH in snow, the presence of 1O2* on illuminated snow or ice has not been studied previously. In this study, our goal is to determine the steady state concentrations of singlet molecular oxygen in illuminated snow samples collected from Summit, Greenland during the summer of 2005. We add furfuryl alcohol (FFA), which acts as a chemical probe of singlet molecular oxygen, to ice pellets made from Greenland snow samples and monitor the rate of loss of FFA during illumination. Our initial results indicate that 1O2* is formed in illuminated Summit samples and that the steady-state concentration of 1O2* is much larger on ice (-10 °C) than in liquid solution (°C) using the same prepared sample. We will present our measured steady-state concentrations of 1O2* as well as the impacts of this oxidant on the lifetimes of trace organics such as PAHs and biogenic phenols in Greenland snow.

  4. Transillumination spatially modulated illumination microscopy for human chromosome imaging

    NASA Astrophysics Data System (ADS)

    Pitris, Costas; Heracleous, Peter; Patsalis, Philippos

    2005-03-01

    Human chromosome analysis is an essential task in cytogenetics, especially in prenatal screening, genetic syndrome diagnosis, cancer pathology research and mutagen dosimetry. Chromosomal analysis begins with the creation of a karyotype, which is a layout of chromosome images organized by decreasing size in pairs. Both manual and automatic classification of chromosomes are limited by the resolution of the microscope and imaging system used. One way to improve the results of classification and even detect subtleties now remaining undetected, is to enhance the resolution of the images. It is possible to achieve lateral resolution beyond the classical limit, by using spatially modulated illumination (SMI) in a wide-field, non-confocal microscope. In this case, the sample is illuminated with spatially modulated light, which makes normally inaccessible high-resolution information visible in the observed image by shifting higher frequencies within the OTF limits of the microscope. Although, SMI microscopes have been reported in the past, this manuscript reports the development of a transillumination microscope for opaque, non-fluorescent samples. The illumination path consisted of a light source illuminating a ruled grating which was subsequently imaged on the sample. The grating was mounted on a rotating and translating stage so that the magnification and rotation of the pattern could be adjusted. The imaging lens was a 1.25 NA oil immersion objective. Test samples showed resolution improvement, as judged from a comparison of the experimentally obtained FWHM. Further studies using smaller fringe distance or laser interference pattern illumination will be evaluated to further optimize the SMI results.

  5. An overview of LED applications for general illumination

    NASA Astrophysics Data System (ADS)

    Pelka, David G.; Patel, Kavita

    2003-11-01

    This paper begins by reviewing the current state of development of LEDs, their existing markets as well as their potential for energy conservation and their potential for gaining market share in the general illumination market. It discusses LED metrics such as chip size, lumens per watt, thermal resistance, and the recommended maximum current rating. The paper then goes on to consider the importance of non-imaging optics for both optically efficient and extremely compact LED lighting systems. Finally, microstructures useful for controlling the fields-of-view of LED lighting systems are considered and described in some detail. An extremely efficient and cost effective microstructure, called kinoform diffusers, is shown to have very unique properties that make this technology almost ideal for shaping the output beams of LED lighting systems. It concludes by illustrating some general illumination LED lighting systems

  6. Combining near-infrared illuminants to optimize venous imaging

    NASA Astrophysics Data System (ADS)

    Paquit, Vincent; Price, Jeffery R.; Mériaudeau, Fabrice; Tobin, Kenneth W., Jr.; Ferrell, Thomas L.

    2007-03-01

    The first and perhaps most important phase of a surgical procedure is the insertion of an intravenous (IV) catheter. Currently, this is performed manually by trained personnel. In some visions of future operating rooms, however, this process is to be replaced by an automated system. We previously presented work for localizing near-surface veins via near-infrared (NIR) imaging in combination with structured light ranging for surface mapping and robotic guidance. In this paper, we describe experiments to determine the best NIR wavelengths to optimize vein contrast for physiological differences such as skin tone and/or the presence of hair on the arm or wrist surface. For illumination, we employ an array of NIR LEDs comprising six different wavelength centers from 740nm to 910nm. We capture imagery of each subject under every possible combination of illuminants and determine the optimal combination of wavelengths for a given subject to maximize vein contrast using linear discriminant analysis.

  7. Illumination system having a plurality of movable sources

    DOEpatents

    Sweatt, William C.; Kubiak, Glenn D.

    2002-01-01

    An illumination system includes several discharge sources that are multiplexed together to reduce the amount of debris generated. The system includes: (a) a first electromagnetic radiation source array that includes a plurality of first activatable radiation source elements that are positioned on a first movable carriage; (b) a second electromagnetic radiation source array that includes a plurality of second activatable radiation source elements that are positioned on a second movable carriage; (c) means for directing electromagnetic radiation from the first electromagnetic radiation source array and electromagnetic radiation from the second electromagnetic radiation source array toward a common optical path; (d) means for synchronizing (i) the movements of the first movable carriage and of the second movable carriage and (ii) the activation of the first electromagnetic radiation source array and of the second electromagnetic radiation source array to provide an essentially continuous illumination of electromagnetic radiation along the common optical path.

  8. Interferometric homogeneity test using adaptive frequency comb illumination.

    PubMed

    Mantel, Klaus; Schwider, Johannes

    2013-03-20

    The homogeneity test of glass plates in a Fizeau interferometer requires the measurement of the glass sample in reflected as well as in transmitted light. For the measurement in transmitted light, the sample has to be inserted into the ray path of a Fizeau or Twyman-Green interferometer, which leads to a nested cavity setup. To separate the interference signals from the different cavities, we illuminate a Fizeau interferometer with an adaptive frequency comb. In this way, rigid glass plates can be measured, and linear variations in the homogeneity can also be detected. The adaptive frequency comb is provided by a variable Fabry-Perot filter under broadband illumination from a superluminescence diode. Compared to approaches using a two-beam interferometer as a filter for the broadband light source, the visibility of the fringe system is considerably higher.

  9. Broadband seismic illumination and resolution analyses based on staining algorithm

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Jia, Xiao-Feng; Xie, Xiao-Bi

    2016-09-01

    Seismic migration moves reflections to their true subsurface positions and yields seismic images of subsurface areas. However, due to limited acquisition aperture, complex overburden structure and target dipping angle, the migration often generates a distorted image of the actual subsurface structure. Seismic illumination and resolution analyses provide a quantitative description of how the above-mentioned factors distort the image. The point spread function (PSF) gives the resolution of the depth image and carries full information about the factors affecting the quality of the image. The staining algorithm establishes a correspondence between a certain structure and its relevant wavefield and reflected data. In this paper, we use the staining algorithm to calculate the PSFs, then use these PSFs for extracting the acquisition dip response and correcting the original depth image by deconvolution. We present relevant results of the SEG salt model. The staining algorithm provides an efficient tool for calculating the PSF and for conducting broadband seismic illumination and resolution analyses.

  10. High-speed compressive range imaging based on active illumination.

    PubMed

    Sun, Yangyang; Yuan, Xin; Pang, Shuo

    2016-10-03

    We report a compressive imaging method based on active illumination, which reconstructs a 3D scene at a frame rate beyond the acquisition speed limit of the camera. We have built an imaging prototype that projects temporally varying illumination pattern and demonstrated a joint reconstruction algorithm that iteratively retrieves both the range and high-temporal-frequency information from the 2D low-frame rate measurement. The reflectance and depth-map videos have been reconstructed at 1000 frames per second (fps) from the measurement captured at 200 fps. The range resolution is in agreement with the resolution calculated from the triangulation methods based on the same system geometry. We expect such an imaging method could become a simple solution to a wide range of applications, including industrial metrology, 3D printing, and vehicle navigations.

  11. 3D fluorescence anisotropy imaging using selective plane illumination microscopy

    PubMed Central

    Hedde, Per Niklas; Ranjit, Suman; Gratton, Enrico

    2015-01-01

    Fluorescence anisotropy imaging is a popular method to visualize changes in organization and conformation of biomolecules within cells and tissues. In such an experiment, depolarization effects resulting from differences in orientation, proximity and rotational mobility of fluorescently labeled molecules are probed with high spatial resolution. Fluorescence anisotropy is typically imaged using laser scanning and epifluorescence-based approaches. Unfortunately, those techniques are limited in either axial resolution, image acquisition speed, or by photobleaching. In the last decade, however, selective plane illumination microscopy has emerged as the preferred choice for three-dimensional time lapse imaging combining axial sectioning capability with fast, camera-based image acquisition, and minimal light exposure. We demonstrate how selective plane illumination microscopy can be utilized for three-dimensional fluorescence anisotropy imaging of live cells. We further examined the formation of focal adhesions by three-dimensional time lapse anisotropy imaging of CHO-K1 cells expressing an EGFP-paxillin fusion protein. PMID:26368202

  12. Optical Fiber Illumination System for visual flight simulation

    NASA Technical Reports Server (NTRS)

    Hollow, R. H.

    1981-01-01

    An electronically controlled lighting system simulating runway, aircraft carrier, and landing aid lights for flight simulations is described. The various colored lights that would be visible to a pilot by day, at dusk, or at night are duplicated at the distances the lights would normally become visible. Plastic optical fiber illuminators using tungsten halogen lights are distributed behind the model. The tips of the fibers of illuminators simulating runway lights are bevelled in order that they may be seen from long distances and at low angles. Fibers representing taxiway lights are pointed and polished for omni-directional visibility. The electronic intensity controls, which can be operated either manually or remotely, regulate the intensity of the lights to simulate changes in distance. A dichronic mirror, infrared filter system is used to maintain color integrity.

  13. The importance of pulsing illumination parameters in LLLT

    NASA Astrophysics Data System (ADS)

    Barolet, D.

    2010-02-01

    The influence of emission parameters in Low Level Light Therapy (LLLT) on cellular responses is not yet fully understood. This study assessed the impact of various light delivery modes on collagen production in human primary fibroblast cultured in monolayers after three treatments with red light emitting diode illumination (630 nm, 8 J/cm2). Human type I collagen was measured in cell culture supernatants with procollagen Type I C-Peptide enzyme immunoassay. Results from this study demonstrated that specific μsec pulsing patterns had a more favorable impact on the ability of fibroblasts to produce collagen de novo than comparator conditions of continuous wave, pulsed 50% duty cycle, and millisecond pulsing domain (72 hours post baseline). The cascade of events leading to collagen production by red illumination may be explained by the photodissociation of nitric oxide from cytochrome c oxidase. Short and intermittent light delivery might enhance this cellular strategy.

  14. Selective plane illumination microscopy techniques in developmental biology

    PubMed Central

    Huisken, Jan; Stainier, Didier Y. R.

    2009-01-01

    Summary Selective plane illumination microscopy (SPIM) and other fluorescence microscopy techniques in which a focused sheet of light serves to illuminate the sample have become increasingly popular in developmental studies. Fluorescence light-sheet microscopy bridges the gap in image quality between fluorescence stereomicroscopy and high-resolution imaging of fixed tissue sections. In addition, high depth penetration, low bleaching and high acquisition speeds make light-sheet microscopy ideally suited for extended time-lapse experiments in live embryos. This review compares the benefits and challenges of light-sheet microscopy with established fluorescence microscopy techniques such as confocal microscopy and discusses the different implementations and applications of this easily adaptable technology. PMID:19465594

  15. Face verification and rejection with illumination variations using MINACE filters

    NASA Astrophysics Data System (ADS)

    Patnaik, Rohit; Casasent, David P.

    2004-04-01

    A face verification system based on the use of a minimum noise and average correlation energy (MINACE) filter for each person is presented that functions with illumination variations present. A separate filter is used for each person; it is a combination of different training images of only that person. The system is tested using both unregistered and registered images from the CMU Pose, Illumination and Expression (PIE) database. The number of correct (PC) and the number of false alarm (PFA) scores are compared for the two cases. Rather than using the same parameters for the filter of each person, an automated iterative filter training and synthesis method is used. A validation set of several other faces is used to achieve parameter selection for good rejection performance. For filter-evaluation, all filters are tested against all images, but the same peak threshold is used for each filter to determine verification and rejection.

  16. Fault Tolerant Algorithm for Structured Illumination Microscopy with Incoherent Light

    NASA Astrophysics Data System (ADS)

    Wang, Kun; Heidingsfelder, Philipp; Gao, Jun; Yu, Liandong; Ott, Peter

    2015-04-01

    In this contribution we present a new algorithm for structured illumination microscopy with incoherent light. Existing algorithms for determining the contrast values of the focal depth response require a high accurate phase shift of the fringe pattern illumination. The presented algorithm, which is robust against inaccurate phase shift of the fringe pattern, reduces significantly the requirements for the phase shift and consequently the costs of the microscope. The new algorithm was tested by a preliminary experiment, whereby the grating was shifted by an elastic guided micro-motion mechanism employing a low-cost stepper motor replacing the conventional expensive piezo drive. The determined focal depth response is very smooth and corresponds very well to the theoretical focal depth response.

  17. Optical photon reassignment with increased axial resolution by structured illumination

    NASA Astrophysics Data System (ADS)

    Roth, Stephan; Heintzmann, Rainer

    2016-12-01

    Fluorescent microscopy methods linked to the reassignment principle as image scanning microscopy (ISM), re-scan confocal (RSC), optical photon reassignment (OPRA) and instant structured illumination microscopy (iSIM) have the potential to replace confocal microscopy as the standard microscopy technique. Photon reassignment methods are known to link the most important properties in biological imaging as resolution, sensitivity, imaging speed and combinability with fluorophores in an elegant way. On the example of OPRA, we show how this method could be easily extended to the third dimension. If OPRA is used in combination with a structured illumination pattern the sectioning ability can be improved while maintaining the very high signal intensity. We present a detailed analysis about the imaging properties of OPRA in three dimensions and show experimental results on biological samples.

  18. Charged domain walls under super-band-gap illumination

    NASA Astrophysics Data System (ADS)

    Sturman, B.; Podivilov, E.

    2017-03-01

    Charged domain walls (CDWs), which possess metallic-type conductivity and can be created and controlled in the bulk of wide-band-gap ferroelectrics, attract nowadays a strong research interest. The most advanced method for production of stable CDWs involves weak super-band-gap illumination. Here, we investigate theoretically the impact of this illumination on the major wall properties including the energy and the spatial profiles of the polarization, of the electrostatic potential, and of the compensating charge carriers. The key material parameters determining the effect of light are the zero-field polarization strength, the dielectric permittivity, and the trap concentration. The main predictions are substantial reduction of the wall energies and decrease of the electric wall potential under light. These features facilitate creation of dense CDWs patterns and accessibility of the metallic-type wall conductivity.

  19. Sensitivity of an illumination system to lamp flicker

    NASA Astrophysics Data System (ADS)

    Rehn, H.

    2008-09-01

    Discharge lamps serve a wide variety of applications and outperform novel light sources such as LEDs in terms of luminous flux and luminance. Unfortunately, such lamps occasionally show arc movements (flicker) which change the amount of light that is coupled into an optical system. A variety of measures in lamp design can suppress flicker tendencies of a lamp but arc movement cannot be totally avoided. In our contribution, we show that the way how the light is collected considerably influences the impact of flicker on the collected luminous flux. We investigate light collection sensitivity of an illumination system as a function of the etendue and of the particular realization of the illumination system. As a result, flicker sensitivity can be substantially reduced at the expense of collection efficiency.

  20. Quantitative sectioning and noise analysis for structured illumination microscopy

    PubMed Central

    Hagen, Nathan; Gao, Liang; Tkaczyk, Tomasz S.

    2011-01-01

    Structured illumination (SI) has long been regarded as a nonquantitative technique for obtaining sectioned microscopic images. Its lack of quantitative results has restricted the use of SI sectioning to qualitative imaging experiments, and has also limited researchers’ ability to compare SI against competing sectioning methods such as confocal microscopy. We show how to modify the standard SI sectioning algorithm to make the technique quantitative, and provide formulas for calculating the noise in the sectioned images. The results indicate that, for an illumination source providing the same spatially-integrated photon flux at the object plane, and for the same effective slice thicknesses, SI sectioning can provide higher SNR images than confocal microscopy for an equivalent setup when the modulation contrast exceeds about 0.09. PMID:22274364

  1. Combining near-infrared illuminants to optimize venous imaging

    SciTech Connect

    Paquit, Vincent C; Price, Jeffery R; Meriaudeau, Fabrice; Tobin Jr, Kenneth William; Ferrell, Thomas L

    2007-01-01

    The first and perhaps most important phase of a surgical procedure is the insertion of an intravenous (IV) catheter. Currently, this is performed manually by trained personnel. In some visions of future operating rooms, however, this process is to be replaced by an automated system. We previously presented work for localizing near-surface veins via near-infrared (NIR) imaging in combination with structured light ranging for surface mapping and robotic guidance. In this paper, we describe experiments to determine the best NIR wavelengths to optimize vein contrast for physiological differences such as skin tone and/or the presence of hair on the arm or wrist surface. For illumination, we employ an array of NIR LEDs comprising six different wavelength centers from 740nm to 910nm. We capture imagery of each subject under every possible combination of illuminants and determine the optimal combination of wavelengths for a given subject to maximize vein contrast using linear discriminant analysis.

  2. Bright afterglow illuminator made of phosphorescent material and fluorescent fibers.

    PubMed

    Saito, M; Yamamoto, K

    2000-08-20

    Phosphorescent oxides and fluorescent dyes were used together to create a fiber-type illuminator that glows in the dark without the need for electric power. Dye-doped polymer fibers, which were bundled at one end, were linearly arrayed in a polysiloxane resin that contained phosphorescent oxide particles. The phosphorescent resin continued to glow for a long time even after the excitation light was removed. Organic dyes in a polymer fiber were excited by the phosphorescence and emitted fluorescence toward the fiber end. Fluorescence from a number of dyes was combined in the long fiber, and, consequently a bright light beam emerged from the fiber end. Useful performance, i.e., high power density, narrow beam divergence, and long afterglow, is demonstrated by the prototype fiber illuminator.

  3. Countermeasure against tailored bright illumination attack for DPS-QKD.

    PubMed

    Honjo, Toshimori; Fujiwara, Mikio; Shimizu, Kaoru; Tamaki, Kiyoshi; Miki, Shigehito; Yamashita, Taro; Terai, Hirotaka; Wang, Zhen; Sasaki, Masahide

    2013-02-11

    We propose a countermeasure against the so-called tailored bright illumination attack for differential-phase-shift QKD (DPS-QKD). By monitoring a rate of coincidence detection at a pair of superconducting nanowire single-photon detectors (SSPDs) which is connected at each of the output ports of Bob's Mach-Zehnder interferometer, Alice and Bob can detect and defeat this kind of attack. We also experimentally confirmed the feasibility of this countermeasure using our 1 GHz-clocked DPS-QKD system. In the emulation of the attack, we achieved much lower power of the bright illumination light compared with the original demonstration by using a pulse stream instead of broad pulses.

  4. Tip Enhanced Raman Spectroscopy and Imaging: an Apical Illumination Geometry

    PubMed Central

    Schultz, Zachary D.; Stranick, Stephan J.; Levin, Ira W.

    2009-01-01

    Results are presented illustrating the use of tip enhanced Raman spectroscopy and imaging in a top-illumination geometry. A radially polarized beam is used to generate an electric field component in the direction of beam propagation, normal to the surface, resulting in a 5× increased enhancement compared to a linearly polarized beam. This multiplicative enhancement facilitates a discrimination of the near field signal from the far field Raman background. The top illumination configuration facilitates the application of TERS for investigating molecules on a variety of surfaces, such as Au, glass, and Si. The near field Raman spectrum is presented of Si(100), rhodamine B, brilliant cresyl blue, and single wall carbon nanotubes. Sufficient enhancement is obtained to permit a sub-diffraction limited resolution Raman imaging of the surface distribution of large bundles of carbon nanotubes of various diameters. PMID:19007457

  5. Array illumination of a Fresnel-Dammann zone plate.

    PubMed

    Ma, Yayao; Ye, Chaochao; Ke, Jie; Zhang, Junyong; Zhu, Jianqiang; Ling, Zunqing

    2016-09-10

    The traditional Dammann grating is a phase-only modulation, and its theoretical foundation is based on far-field diffraction. Here we extend the traditional Fresnel zone plate (FZP) into a Fresnel-Dammann zone plate (FDZP), which is, in essence, considered as a FZP with Dammann modulation. Different from the Dammann grating, a single FDZP can generate array illumination from the near field to the far field by means of amplitude-only modulation in the absence of phase modulation. We then give some array illuminations operated in a water window to validate the feasibility and validity. This kind of wave-front modulation technology can be applied to array focusing and imaging from the x-ray to the EUV region.

  6. Illumination of dense urban areas by light redirecting panels.

    PubMed

    El-Henawy, Sally I; Mohamed, Mohamed W N; Mashaly, Islam A; Mohamed, Osama N; Galal, Ola; Taha, Iman; Nassar, Khaled; Safwat, Amr M E

    2014-05-05

    With the high population growth rate, especially in developing countries, and the scarcity of land resources, buildings are becoming so close to each other, depriving the lower floors and the alleys from sunlight and consequently causing health problems. Therefore, there is an urgent need for cost-effective efficient light redirecting panels that guide sun rays into those dim places. In this paper, we address this problem. A novel sine wave based panel is presented to redirect/diverge light downward and enhance the illumination level in those dark places. Simulation results show that the proposed panel improves the illuminance values by more than 200% and 400% in autumn and winter respectively, operates over wide solar altitude ranges, and redirects light efficiently. Experimental and simulation results are in good agreement.

  7. TIR optics for non-rotationally symmetric illumination design

    NASA Astrophysics Data System (ADS)

    Domhardt, André; Weingaertner, Simon; Rohlfing, Udo; Lemmer, Uli

    2008-09-01

    High-Power-LEDs have reached a development stage that affords their reasonable application to general illumination. Nonimaging total internal reflection optics (TIR optics) that generate non-rotationally symmetric light distributions are proper components to preserve the advantages associated with this type of light source. Thus, high efficiency has to be reconciled, e.g., with the use of freeform surfaces. This contribution investigates the development of TIR optics for LED-based illumination applications. First, we consider rotationally symmetric TIR optics in order to illustrate their functional principle and demonstrate some special design criteria. Second, we apply them to non-rotationally cases using the tailoring technique. Finally, we illustrate various aspects of the design process with selected examples.

  8. Is White Light the Best Illumination for Palmprint Recognition?

    NASA Astrophysics Data System (ADS)

    Guo, Zhenhua; Zhang, David; Zhang, Lei

    Palmprint as a new biometric has received great research attention in the past decades. It owns many merits, such as robustness, low cost, user friendliness, and high accuracy. Most of the current palmprint recognition systems use an active light to acquire clear palmprint images. Thus, light source is a key component in the system to capture enough of discriminant information for palmprint recognition. To the best of our knowledge, white light is the most widely used light source. However, little work has been done on investigating whether white light is the best illumination for palmprint recognition. In this study, we empirically compared palmprint recognition accuracy using white light and other six different color lights. The experiments on a large database show that white light is not the optimal illumination for palmprint recognition. This finding will be useful to future palmprint recognition system design.

  9. Response of silicon solar cell to pulsed laser illumination

    NASA Technical Reports Server (NTRS)

    Willowby, D.; Alexander, D.; Edge, T.; Herren, K.

    1993-01-01

    The response of silicon solar cell(s) to pulsed laser illumination is discussed. The motivation was due to the interest of Earth to space/Moon power beaming applications. When this work began, it was not known if solar cells would respond to laser light with pulse lengths in the nanosecond range and a repetition frequency in the kHz range. This is because the laser pulse would be shorter than the minority carrier lifetime of silicon. A 20-nanosecond (ns) full width half max (FWHM) pulse from an aluminum-gallium/arsenide (Al-Ga-As) diode laser was used to illuminate silicon solar cells at a wavelength of 885 nanometers (nm). Using a high-speed digital oscilloscope, the response of the solar cells to individual pulses across various resistive loads was observed and recorded.

  10. MONIM: the new Met Office Night Illumination Model

    NASA Astrophysics Data System (ADS)

    Revell, S. J.; Hignett, P.

    2004-09-01

    This paper describes a new model developed by the Met Office to predict night-time light levels. The Met Office Night Illumination Model (MONIM) predicts light levels both in the visible (photopic) range and in the waveband to which night vision goggles (NVGs) are sensitive. The model will be used operationally for support of night-time flying operations. The model is described in detail and its light-level forecasts are compared with observations.

  11. Even Illumination from Fiber-Optic-Coupled Laser Diodes

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.

    2006-01-01

    A method of equipping fiber-optic-coupled laser diodes to evenly illuminate specified fields of view has been proposed. The essence of the method is to shape the tips of the optical fibers into suitably designed diffractive optical elements. One of the main benefits afforded by the method would be more nearly complete utilization of the available light. Diffractive optics is a relatively new field of optics in which laser beams are shaped by use of diffraction instead of refraction.

  12. Structured illumination microscopy for vibrational molecular imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Watanabe, Kozue; Palonpon, Almar F.; Smith, Nicholas I.; Chiu, Liang-da; Kasai, Atsushi; Hashimoto, Hitoshi; Kawata, Satoshi; Fujita, Katsumasa

    2016-09-01

    Raman microscopy is a powerful tool for analytical imaging. The wavelength shift of Raman scattering corresponds to molecular vibrational energy. Therefore, we can access rich chemical information, such as distribution, concentration, and chemical environment of sample molecules. Despite these strengths of Raman microscopy, the spatial resolution has been a limiting factor for many practical applications. In this study, we developed a large-area, high-resolution Raman microscope by utilizing structured illumination microscopy (SIM) to overcome the spatial resolution limit. A structured line-illumination (SLI) Raman microscope was constructed. The structured illumination is introduced along the line direction by the interference of two line-shaped beams. In SIM, the spatial frequency mixing between structured illumination and Raman scattering from the sample allows access to the high spatial frequency information beyond the conventional cut-off. As a result, the FWHM of 40-nm fluorescence particle images showed a clear resolution enhancement in the line direction: 366 nm in LI and 199 nm in SLI microscope. Using the developed microscope, we successfully demonstrated high-resolution Raman imaging of various kinds of specimens, such as few-layer graphene, graphite, mouse brain tissue, and polymer nanoparticles. The high resolution Raman images showed the capability to extract original spectral features from the mixed Raman spectra of a multi-component sample because of the enhanced spatial resolution, which is advantageous in observing complex spectral features. The Raman microscopy technique reported here enables us to see the detailed chemical structures of chemical, biological, and medical samples with a spatial resolution smaller than 200 nm.

  13. Army Illumination Model v2 User’s Manual

    DTIC Science & Technology

    2011-09-01

    diagnostic output requested (record seven); the clouds themselves are comprised of three layers, the high layer containing 10% thin cirrus (Ci...fairly clear atmosphere; transmission through and reflection by nine cloud types are available as is Lunar illumination as a function of time-of-day and...SUBJECT TERMS Urban elimination, clouds , target acquisition 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES

  14. Multimode tapered optical light pipe for illumination systems

    NASA Astrophysics Data System (ADS)

    Romańczuk, Patryk; Pietrzycki, Marcin; Źmojda, Jacek; Kochanowicz, Marcin; Dorosz, Dominik

    2015-09-01

    In the article the multimode tapered optical light pipe for illumination systems was investigated. Based on tree light emitting diodes at the wavelength of 460 nm (blue), 528 nm (green) and 631 nm (red) possibility of white light emission on the output surface of the tapered light pipe was submitted. Influence of optical power of LEDs on the colour coordinates (CIE-1931) has been investigated.

  15. Structured white-light illumination for diagnostic investigations

    NASA Astrophysics Data System (ADS)

    Schau, P.; Brandes, A.; Frenner, K.; Kienle, A.; Osten, W.

    2013-04-01

    The optical coherence tomography (OCT) is an important technology for non-invasive, in vivo medical diagnostics. It enables the high-resolution recording of two-dimensional tomograms or three-dimensional volumes of biological tissue. Two mechanisms help separating the signal from the scattering background. First, reflected or backscattered light from outside the focal spot is suppressed by confocal discrimination. Additionally, the signal modulation is enhanced due to identical optical path lengths of both branches of the white light interferometry setup. Since the OCT relies on the interference between reference light and scattered light, this method cannot be readily extended for fluorescence measurements. An alternative approach is the confocal fluorescence microscopy, which uses confocal microscopy to suppress the fluorescent light from outside the focal spot. Hence, only the fluorescent light in the focal plane, which is 3 to 4 magnitudes lower in intensity than the excitation light, is detected. However, the surrounding area is illuminated with full intensity, which might cause photo-bleaching. There are also other promising approaches such as the two-photon excitation microscopy or fluorescence lifetime microscopy, which we will not cover in more detail. For fluorescence measurements of strongly-scattering samples such as biological tissue but also for technical surfaces, we propose a structured white-light illumination. We present two different approaches for the sample illumination utilizing a white light laser or a white light LED, respectively. We show first simulations of the individual illumination setups and their impact on the scattering within the sample. Furthermore, we investigated the distribution of the fluorescent light that reaches the detection part of the device when excited within a scattering medium, for this purpose we implemented a novel fast-converging algorithm for conditional fluence rate in our Monte Carlo algorithm.

  16. Illuminating a dialectical transformative activist stance in education

    NASA Astrophysics Data System (ADS)

    Ritchie, Stephen M.

    2008-07-01

    In this essay I comment on Stetsenko's (2008) essay that draws together the work of Vygotsky, Piaget and Dewey, as she attempts to counter the `new' reductionist synthesis in public educational policy. While this theoretical work is helpful, it could be enhanced further by illuminating everyday practices of learners. I pose some questions that might provoke ongoing discussions by researchers as they transform collaboratively cultural-historical activity theory.

  17. Image recombination transform algorithm for superresolution structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Xing; Lei, Ming; Dan, Dan; Yao, Baoli; Yang, Yanlong; Qian, Jia; Chen, Guangde; Bianco, Piero R.

    2016-09-01

    Structured illumination microscopy (SIM) is an attractive choice for fast superresolution imaging. The generation of structured illumination patterns made by interference of laser beams is broadly employed to obtain high modulation depth of patterns, while the polarizations of the laser beams must be elaborately controlled to guarantee the high contrast of interference intensity, which brings a more complex configuration for the polarization control. The emerging pattern projection strategy is much more compact, but the modulation depth of patterns is deteriorated by the optical transfer function of the optical system, especially in high spatial frequency near the diffraction limit. Therefore, the traditional superresolution reconstruction algorithm for interference-based SIM will suffer from many artifacts in the case of projection-based SIM that possesses a low modulation depth. Here, we propose an alternative reconstruction algorithm based on image recombination transform, which provides an alternative solution to address this problem even in a weak modulation depth. We demonstrated the effectiveness of this algorithm in the multicolor superresolution imaging of bovine pulmonary arterial endothelial cells in our developed projection-based SIM system, which applies a computer controlled digital micromirror device for fast fringe generation and multicolor light-emitting diodes for illumination. The merit of the system incorporated with the proposed algorithm allows for a low excitation intensity fluorescence imaging even less than 1 W/cm2, which is beneficial for the long-term, in vivo superresolved imaging of live cells and tissues.

  18. The effect of illuminant position on perceived curvature.

    PubMed

    Curran, W; Johnston, A

    1996-05-01

    In shaded scenes surface features can appear either concave or convex, depending upon the viewer's judgement about the direction of the prevailing illumination. If other curvature cues are added to the image this ambiguity can be removed. However, it is not clear to what extent, if any, illuminant position exerts an influence on the perceived magnitude of surface curvature. Subjects were presented with pairs of spherical surface patches in a curvature matching task. The patches were defined by shading and texture cues. The perceived curvature of a standard patch was measured as a function of light source position. We found a clear effect of light source position on apparent curvature. Perceived curvature decreased as light source tilt increased and as light source slant decreased. We also found that the strength of this effect is determined partly by a surface's reflectance function and partly by the relative weight of the texture cue. When a specular component was added to the stimuli, the effect of light source orientation was weakened. The weight of the texture cue was manipulated by disrupting the regular distribution of texture elements. We found an inverse relationship between the strength of the effect and the weight of the texture cue: lowering the texture cue weight resulted in an enhancement of the illuminant position effect.

  19. Wide-field Fourier ptychographic microscopy using laser illumination source

    PubMed Central

    Chung, Jaebum; Lu, Hangwen; Ou, Xiaoze; Zhou, Haojiang; Yang, Changhuei

    2016-01-01

    Fourier ptychographic (FP) microscopy is a coherent imaging method that can synthesize an image with a higher bandwidth using multiple low-bandwidth images captured at different spatial frequency regions. The method’s demand for multiple images drives the need for a brighter illumination scheme and a high-frame-rate camera for a faster acquisition. We report the use of a guided laser beam as an illumination source for an FP microscope. It uses a mirror array and a 2-dimensional scanning Galvo mirror system to provide a sample with plane-wave illuminations at diverse incidence angles. The use of a laser presents speckles in the image capturing process due to reflections between glass surfaces in the system. They appear as slowly varying background fluctuations in the final reconstructed image. We are able to mitigate these artifacts by including a phase image obtained by differential phase contrast (DPC) deconvolution in the FP algorithm. We use a 1-Watt laser configured to provide a collimated beam with 150 mW of power and beam diameter of 1 cm to allow for the total capturing time of 0.96 seconds for 96 raw FPM input images in our system, with the camera sensor’s frame rate being the bottleneck for speed. We demonstrate a factor of 4 resolution improvement using a 0.1 NA objective lens over the full camera field-of-view of 2.7 mm by 1.5 mm. PMID:27896016

  20. Color digital lensless holographic microscopy: laser versus LED illumination.

    PubMed

    Garcia-Sucerquia, Jorge

    2016-08-20

    A comparison of the performance of color digital lensless holographic microscopy (CDLHM) as utilized for illumination of RGB lasers or a super-bright white-light LED with a set of spectral filters is presented. As the use of lasers in CDLHM conceals the possibility of having a compact, lightweight, portable, and low cost microscope, and additionally the limited available laser radiation wavelengths limit a real multispectral imaging microscope, here we present the use of super-bright white-light LED and spectral filters for illuminating the sample. The performance of RGB laser-CDLHM and LED-CDLHM is evaluated on imaging a section of the head of a Drosophila melanogaster fly. This comparison shows that there is trade-off between the spatial resolution of the microscope and the light sources utilized, which can be understood with regard to the coherence properties of the illuminating light. Despite the smaller spatial coherence features of LED-CDLHM in comparison with laser-CDLHM, the former shows promise as a portable RGB digital lensless holographic microscope that could be extended to other wavelengths by the use of different spectral filters.

  1. Standards for illumination of digital prints and photographs

    NASA Astrophysics Data System (ADS)

    Green, Phil

    2010-06-01

    Standards for illuminating digital prints and photographs have a number of quite different applications. In the graphic arts industry, the main applications are defined as appraisal and critical comparison, for which 500lux and 2000lux are specified in ISO 3664. In the museum world much lower levels of illumination are imposed when artefacts are considered to be prone to damage from such exposure. For display and storage of photographic prints, BS 5454:2000 is applicable and specifies maximum levels of 50 lux and 200 lux respectively. While these standards provide recommendations for exposure to radiant energy with the goal of limiting damage to materials and maximising visual discrimination, there is a need for more data on the radiative damage spectrum for the materials used in digital prints and photographs and other artefacts, and on the viewing conditions which can maximise visual performance for specific tasks. It is recommended that radiative exposure is measured in watts per square metre instead of lux to give a better indication of the propensity for radiative damage of a given illumination source.

  2. PSM design for inverse lithography with partially coherent illumination.

    PubMed

    Ma, Xu; Arce, Gonzalo R

    2008-11-24

    Phase-shifting masks (PSM) are resolution enhancement techniques (RET) used extensively in the semiconductor industry to improve the resolution and pattern fidelity of optical lithography. Recently, a set of gradient-based PSM optimization methods have been developed to solve for the inverse lithography problem under coherent illumination. Most practical lithography systems, however, use partially coherent illumination due to non-zero width and off-axis light sources, which introduce partial coherence factors that must be accounted for in the optimization of PSMs. This paper thus focuses on developing a framework for gradient-based PSM optimization methods which account for the inherent nonlinearities of partially coherent illumination. In particular, the singular value decomposition (SVD) is used to expand the partially coherent imaging equation by eigenfunctions into a sum of coherent systems (SOCS). The first order coherent approximation corresponding to the largest eigenvalue is used in the PSM optimization. In order to influence the solution patterns to have more desirable manufacturability properties and higher fidelity, a post-processing of the mask pattern based on the 2D discrete cosine transformation (DCT) is introduced. Furthermore, a photoresist tone reversing technique is exploited in the design of PSMs to project extremely sparse patterns.

  3. Improved Starting Materials for Back-Illuminated Imagers

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata

    2009-01-01

    An improved type of starting materials for the fabrication of silicon-based imaging integrated circuits that include back-illuminated photodetectors has been conceived, and a process for making these starting materials is undergoing development. These materials are intended to enable reductions in dark currents and increases in quantum efficiencies, relative to those of comparable imagers made from prior silicon-on-insulator (SOI) starting materials. Some background information is prerequisite to a meaningful description of the improved starting materials and process. A prior SOI starting material, depicted in the upper part the figure, includes: a) A device layer on the front side, typically between 2 and 20 m thick, made of p-doped silicon (that is, silicon lightly doped with an electron acceptor, which is typically boron); b) A buried oxide (BOX) layer (that is, a buried layer of oxidized silicon) between 0.2 and 0.5 m thick; and c) A silicon handle layer (also known as a handle wafer) on the back side, between about 600 and 650 m thick. After fabrication of the imager circuitry in and on the device layer, the handle wafer is etched away, the BOX layer acting as an etch stop. In subsequent operation of the imager, light enters from the back, through the BOX layer. The advantages of back illumination over front illumination have been discussed in prior NASA Tech Briefs articles.

  4. Root planing with interdental papilla reflection and fiber optic illumination.

    PubMed

    Reinhardt, R A; Johnson, G K; Tussing, G J

    1985-12-01

    The complete removal of accretions during closed scaling and root planing in moderate-deep pockets is difficult, presumably due to inadequate mechanical and visual access. The purpose of this study was to evaluate the effect of minimal papilla reflection and illumination with a prototype fiber optic unit on root planing efficiency. Nonmolar teeth with moderate-deep interproximal pockets (greater than 3 mm) in four patients scheduled to receive immediate complete dentures were randomly divided into groups for treatment: Group I--interproximal root planing augmented by papilla reflection and fiber optic illumination (n = 26 surfaces); Group II--interproximal root planing with papilla reflection only (n = 24); Group III--untreated controls (n = 23). Immediately after treatment, the experimental teeth were extracted, stained with toluidine blue and interproximal areas were evaluated for remaining accretions with a microscope-digitizing pad-computer system. Significantly less (P less than 0.01) root surface was covered by deposits in Group I than Group II (0.57 +/- 0.29% vs. 2.42 +/- 0.63%), and both treatment groups had fewer (P less than 0.0005) accretions than untreated controls (57.72 +/- 3.40%). These results suggest that root planing with papilla reflection produces an interproximal surface with few remaining deposits, and fiber optic illumination and transillumination further enhance this effect.

  5. Automated illumination control for use in ophthalmic endoscopy

    NASA Astrophysics Data System (ADS)

    Blessing, Patrick; Niederer, Peter F.; Rol, Pascal O.; Hafliger, J.

    2000-05-01

    In endoscopic ophthalmic procedures care has to be exercised that the retina is protected from overexposure. Accordingly, it is advantageous if the endoscope is equipped with a stable and reliable automatic illumination control. To this end, an illumination control system has been devised, which consists of a mechanical iris and a digital control algorithm. The iris is designed such that it influences neither the spectral composition of the lightsource nor its aperture. It is furthermore linear with respect to the light intensity such that a fast control algorithm based on the data of a digital video camera used for observation purposes can be implemented. In order that no false signals are induced from specular reflections caused, e.g., by operating tools held in front of the camera, the control algorithm is designed such that reflections and true overexposure are distinguished from each other. For this purpose, the field of view is subdivided into small sectors and a statistical evaluation is made. The application under realistic conditions shows that the unit provides the user with a well illuminated image while the retina is reliably protected from overexposure.

  6. Small angle x-ray scattering with edge-illumination

    NASA Astrophysics Data System (ADS)

    Modregger, Peter; Cremona, Tiziana P.; Benarafa, Charaf; Schittny, Johannes C.; Olivo, Alessandro; Endrizzi, Marco

    2016-08-01

    Sensitivity to sub-pixel sample features has been demonstrated as a valuable capability of phase contrast x-ray imaging. Here, we report on a method to obtain angular-resolved small angle x-ray scattering distributions with edge-illumination- based imaging utilizing incoherent illumination from an x-ray tube. Our approach provides both the three established image modalities (absorption, differential phase and scatter strength), plus a number of additional contrasts related to unresolved sample features. The complementarity of these contrasts is experimentally validated by using different materials in powder form. As a significant application example we show that the extended complementary contrasts could allow the diagnosis of pulmonary emphysema in a murine model. In support of this, we demonstrate that the properties of the retrieved scattering distributions are consistent with the expectation of increased feature sizes related to pulmonary emphysema. Combined with the simplicity of implementation of edge-illumination, these findings suggest a high potential for exploiting extended sub-pixel contrasts in the diagnosis of lung diseases and beyond.

  7. Light pollution: the possible consequences of excessive illumination on retina

    PubMed Central

    Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

    2016-01-01

    Light is the visible part of the electromagnetic radiation within a range of 380–780 nm; (400–700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution. PMID:26541085

  8. Small angle x-ray scattering with edge-illumination

    PubMed Central

    Modregger, Peter; Cremona, Tiziana P.; Benarafa, Charaf; Schittny, Johannes C.; Olivo, Alessandro; Endrizzi, Marco

    2016-01-01

    Sensitivity to sub-pixel sample features has been demonstrated as a valuable capability of phase contrast x-ray imaging. Here, we report on a method to obtain angular-resolved small angle x-ray scattering distributions with edge-illumination- based imaging utilizing incoherent illumination from an x-ray tube. Our approach provides both the three established image modalities (absorption, differential phase and scatter strength), plus a number of additional contrasts related to unresolved sample features. The complementarity of these contrasts is experimentally validated by using different materials in powder form. As a significant application example we show that the extended complementary contrasts could allow the diagnosis of pulmonary emphysema in a murine model. In support of this, we demonstrate that the properties of the retrieved scattering distributions are consistent with the expectation of increased feature sizes related to pulmonary emphysema. Combined with the simplicity of implementation of edge-illumination, these findings suggest a high potential for exploiting extended sub-pixel contrasts in the diagnosis of lung diseases and beyond. PMID:27491917

  9. Light pollution: the possible consequences of excessive illumination on retina.

    PubMed

    Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

    2016-02-01

    Light is the visible part of the electromagnetic radiation within a range of 380-780 nm; (400-700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution.

  10. Skin image illumination modeling and chromophore identification for melanoma diagnosis

    NASA Astrophysics Data System (ADS)

    Liu, Zhao; Zerubia, Josiane

    2015-05-01

    The presence of illumination variation in dermatological images has a negative impact on the automatic detection and analysis of cutaneous lesions. This paper proposes a new illumination modeling and chromophore identification method to correct lighting variation in skin lesion images, as well as to extract melanin and hemoglobin concentrations of human skin, based on an adaptive bilateral decomposition and a weighted polynomial curve fitting, with the knowledge of a multi-layered skin model. Different from state-of-the-art approaches based on the Lambert law, the proposed method, considering both specular reflection and diffuse reflection of the skin, enables us to address highlight and strong shading effects usually existing in skin color images captured in an uncontrolled environment. The derived melanin and hemoglobin indices, directly relating to the pathological tissue conditions, tend to be less influenced by external imaging factors and are more efficient in describing pigmentation distributions. Experiments show that the proposed method gave better visual results and superior lesion segmentation, when compared to two other illumination correction algorithms, both designed specifically for dermatological images. For computer-aided diagnosis of melanoma, sensitivity achieves 85.52% when using our chromophore descriptors, which is 8~20% higher than those derived from other color descriptors. This demonstrates the benefit of the proposed method for automatic skin disease analysis.

  11. Random laser illumination: an ideal source for biomedical polarization imaging?

    NASA Astrophysics Data System (ADS)

    Carvalho, Mariana T.; Lotay, Amrit S.; Kenny, Fiona M.; Girkin, John M.; Gomes, Anderson S. L.

    2016-03-01

    Imaging applications increasingly require light sources with high spectral density (power over spectral bandwidth. This has led in many cases to the replacement of conventional thermal light sources with bright light-emitting diodes (LEDs), lasers and superluminescent diodes. Although lasers and superluminescent diodes appear to be ideal light sources due to their narrow bandwidth and power, however, in the case of full-field imaging, their spatial coherence leads to coherent artefacts, such as speckle, that corrupt the image. LEDs, in contrast, have lower spatial coherence and thus seem the natural choice, but they have low spectral density. Random Lasers are an unconventional type of laser that can be engineered to provide low spatial coherence with high spectral density. These characteristics makes them potential sources for biological imaging applications where specific absorption and reflection are the characteristics required for state of the art imaging. In this work, a Random Laser (RL) is used to demonstrate speckle-free full-field imaging for polarization-dependent imaging in an epi-illumination configuration. We compare LED and RL illumination analysing the resulting images demonstrating that the RL illumination produces an imaging system with higher performance (image quality and spectral density) than that provided by LEDs.

  12. Effect of distorted illumination waves on coherent diffraction microscopy

    SciTech Connect

    Kohmura, Yoshiki; Nishino, Yoshinori; Ishikawa, Tetsuya; Miao Jianwei

    2005-12-15

    Coherent diffraction microscopy requires a well-defined illumination wave such as a plane wave on a specimen. Experimentally, a small pinhole or a focused beam is often used to reduce the illumination area but they unavoidably distort the waves. The distortion of the illumination wave causes artifacts in the phase retrieval of oversampled diffraction patterns. Using computer simulations, we searched for the conditions where strong artifacts arise by changing the Fresnel number, pinhole size, alignment error and photon statistics. The experimental setup with Fresnel number of around 1 and smaller than 1 realized a small reconstruction error when the pinhole radius is larger than a few times the specimen size. These conditions are suitable for the rotation of specimens for the three-dimensional (3D) observations. Such investigation will have an impact in the design of coherent diffraction microscopes for the 3D characterization of nanoscale materials and biological systems using the third generation synchrotron radiation and future x-ray free-electron lasers.

  13. Köhler integrators embedded into illumination optics add functionality

    NASA Astrophysics Data System (ADS)

    Dross, O.; Mohedano, R.; Hernández, M.; Cvetkovic, A.; Miñano, J. C.; Benítez, P.

    2008-09-01

    The Köhler illumination concept was originally invented to achieve uniform illumination in microscopy1. Köhler integrators can also be formed by arrays of lenticulations that can be any combination of reflective and/or refractive surfaces, organized in corresponding pairs. Arrays of integrating facets can be arranged not only on flat surfaces but on rotationally symmetric and even freeform surfaces6. Currently flat lenslet arrays are widely applied as homogenizing optics2 for lithography, machine vision illumination, and projection. Adding Köhler facets onto already designed surfaces can improve the optical system performance, while respecting its original function. In general, the optics output can be made somewhat independent of the source characteristics, although at the expense of a slight ètendue dilution or efficiency losses. This work revises the Köhler concept and its application to different kind of optics, ranging from photovoltaic concentrators to automotive LED headlights. In the former, irradiance peaks on the solar cell can be avoided, while preserving high aiming tolerance (acceptance) of the solar concentrator. In the latter, LEDs drawbacks like large source image sizes, source misalignments, ill defined source edges, and low source radiance can be compensated.

  14. 77 FR 57083 - American Illuminating Company, LLC; Supplemental Notice that Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission American Illuminating Company, LLC; Supplemental Notice that Initial Market... in the above-referenced proceeding, of American Illuminating Company, LLC's application for...

  15. 77 FR 63308 - J. William Foley Incorporated v. United Illuminating Company; Notice of Complaint

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission J. William Foley Incorporated v. United Illuminating Company; Notice of... complaint against United Illuminating Company (Respondent) alleging that the Respondent's inclusion...

  16. Implementation of pattern-specific illumination pupil optimization on Step & Scan systems

    NASA Astrophysics Data System (ADS)

    Engelen, Andre; Socha, Robert J.; Hendrickx, Eric; Scheepers, Wieger; Nowak, Frank; Van Dam, Marco; Liebchen, Armin; Faas, Denis A.

    2004-05-01

    Step&Scan systems are pushed towards low k1 applications. Contrast enhancement techniques are crucial for successful implementation of these applications in a production environment. A NA - sigma - illumination mode optimizer and a contrast-based optimization algorithm are implemented in LithoCruiser in order to optimize illumination setting and illumination pupil for a specific repetitive pattern. Calculated illumination pupils have been realized using Diffractive Optical Elements (DOE), which are supported by ASML's AERIAL II illuminator. The qualification of the illumination pupil is done using inline metrology on the ASML Step & Scan system. This paper describes the process of pattern specific illumination optimization for a given mask. Multiple examples will be used to demonstrate the advantage of using non-standard illumination pupils.

  17. Solving the MCAO partial illumination issue and laboratory results

    NASA Astrophysics Data System (ADS)

    Santhakumari, K. K. R.; Arcidiacono, C.; Bertram, T.; Berwein, J.; Herbst, T. M.; Ragazzoni, R.

    2016-07-01

    Telescopes or instruments equipped with Multi-Conjugate Adaptive Optics (MCAO) provide uniform turbulence correction over a wide Field of View (FoV), thereby overcoming the problems of isoplanatism and enabling previously challenging science. LINC-NIRVANA (LN), the German-Italian near-infrared high-resolution imager for the Large Binocular Telescope (LBT), has an advanced and unique MCAO module, which uses the Optical Co-addition of Layer- Oriented Multiple-FoV Natural Guide Star approach to MCAO with pyramid wavefront sensing. The layer-oriented wavefront correction can be performed by conjugating the Deformable Mirrors (DM) and the respective Wavefront Sensors (WFS) to the corresponding atmospheric layers. LN corrects for the aberrations in two different layers. The ground layer, conjugated to the telescope pupil 100m above LBT, is corrected by the Ground-layer Wavefront Sensors (GWS) driving the LBT adaptive secondary mirrors, and a higher layer 7.1km above the telescope is corrected by the High-layer Wavefront Sensors (HWS) driving a pair of Xinetics DMs on the LN bench. At the ground layer, the footprints of the stars overlap completely and every star footprint illuminates the entire pupil-plane. However, for a higher layer, the footprints do not overlap completely and each star illuminates a different region of the conjugated plane. Lack of stars, therefore, results in some regions in this "meta-pupil"-plane not being illuminated, implying no information regarding the aberrations in these areas. The optimum way of correcting the high layer, given this limited information, is the crux of the "partial illumination issue". In this paper, we propose a solution for this issue and discuss laboratory results from the aligned LN bench in the lab. Currently, LN has completed the re-integration and re-alignment at LBT. In early June 2016, we tested our partial illumination algorithm in the instrument's final configuration in the LBT mountain lab, using simulated stars

  18. Applying local Gabor ternary pattern for video-based illumination variable face recognition

    NASA Astrophysics Data System (ADS)

    Wang, Huafeng; Han, Yong; Zhang, Zhaoxiang

    2011-12-01

    The illumination variation problem is one of the well-known problems in face recognition in uncontrolled environment. Due to that both Gabor feature and LTP(local ternary pattern) are testified to be robust to illumination variations, we proposed a new approach which achieved illumination variable face recognition by combining Gabor filters with LTP operator. The experimental results compared with the published results on Yale-B and CMU PIE face database of changing illumination verify the validity of the proposed method.

  19. Applying local Gabor ternary pattern for video-based illumination variable face recognition

    NASA Astrophysics Data System (ADS)

    Wang, Huafeng; Han, Yong; Zhang, Zhaoxiang

    2012-01-01

    The illumination variation problem is one of the well-known problems in face recognition in uncontrolled environment. Due to that both Gabor feature and LTP(local ternary pattern) are testified to be robust to illumination variations, we proposed a new approach which achieved illumination variable face recognition by combining Gabor filters with LTP operator. The experimental results compared with the published results on Yale-B and CMU PIE face database of changing illumination verify the validity of the proposed method.

  20. Coherent x-ray wavefront reconstruction of a partially illuminated Fresnel zone plate.

    PubMed

    Mastropietro, F; Carbone, D; Diaz, A; Eymery, J; Sentenac, A; Metzger, T H; Chamard, V; Favre-Nicolin, V

    2011-09-26

    A detailed characterization of the coherent x-ray wavefront produced by a partially illuminated Fresnel zone plate is presented. We show, by numerical and experimental approaches, how the beam size and the focal depth are strongly influenced by the illumination conditions, while the phase of the focal spot remains constant. These results confirm that the partial illumination can be used for coherent diffraction experiments. Finally, we demonstrate the possibility of reconstructing the complex-valued illumination function by simple measurement of the far field intensity in the specific case of partial illumination.

  1. Inclined selective plane illumination microscopy adaptor for conventional microscopes.

    PubMed

    Cutrale, Francesco; Gratton, Enrico

    2012-11-01

    Driven by the biological sciences, there is an increased need for imaging modalities capable of live cell imaging with high spatial and temporal resolution. To achieve this goal in a comprehensive manner, three-dimensional acquisitions are necessary. Ideal features of a modern microscope system should include high imaging speed, high contrast ratio, low photo-bleaching and photo-toxicity, good resolution in a 3D context, and mosaic acquisition for large samples. Given the importance of collecting data in live sample further increases the technical challenges required to solve these issues. This work presents a practical version of a microscopy method, Selective Plane Illumination Microscopy re-introduced by Huisken et al. (Science2004,305,1007-1009). This method is gaining importance in the biomedical field, but its use is limited by difficulties associated with unconventional microscope design which employs two objectives and a particular kind of sample preparation needed to insert the sample between the objectives. Based on the selective plane illumination principle but with a design similar to the Total Internal Reflection Fluorescence microscope, Dunsby (Dunsby, Opt Express 2008,16,20306-20316) demonstrated the oblique plane microscope (OPM) using a single objective which uses conventional sample preparation protocols. However, the Dunsby instrument was not intended to be part of a commercial microscope. In this work, we describe a system with the advantages of OPM and that can be used as an adaptor to commonly used microscopes, such as IX-71 Olympus, simplifying the construction of the OPM and increasing performance of a conventional microscope. We named our design inclined selective plane illumination microscope (iSPIM).

  2. Contrast- and illumination-invariant object recognition from active sensation.

    PubMed

    Rentschler, Ingo; Osman, Erol; Jüttner, Martin

    2009-01-01

    It has been suggested that the deleterious effect of contrast reversal on visual recognition is unique to faces, not objects. Here we show from priming, supervised category learning, and generalization that there is no such thing as general invariance of recognition of non-face objects against contrast reversal and, likewise, changes in direction of illumination. However, when recognition varies with rendering conditions, invariance may be restored and effects of continuous learning may be reduced by providing prior object knowledge from active sensation. Our findings suggest that the degree of contrast invariance achieved reflects functional characteristics of object representations learned in a task-dependent fashion.

  3. Vertically illuminated TW-UTC photodiodes for terahertz generation

    NASA Astrophysics Data System (ADS)

    Barrientos Z., Claudio; Calle, Victor; Diaz, Marcos; Mena, F. Patricio; Vukusic, Josip; Stake, Jan; Michael, Ernest A.

    2010-07-01

    More efficient continuous-wave photonic nearinfrared mixers as terahertz sources are investigated with the motivation to develop a universal photonic local oscillator for astronomical submillimeter/terahertz receiver systems. For this, we develop new concepts for vertically illuminated traveling-wave (TW) photomixers, TW Uni-Travelling Carrier (UTC) photodiodes. Device simulation/modeling and optical/terahertz testing is being done in the new terahertz photonics laboratory at the Electrical Engineering Department of the University of Chile, whereas device fabrication is performed at the MC2 cleanroom facility at Chalmers Technical University. We report on first progress in this direction.

  4. Vertically Illuminated TW-UTC Photodiodes for Terahertz Generation

    NASA Astrophysics Data System (ADS)

    Barrientos, C.; Calle, V.; Diaz, M.; Mena, F. P.; Vukusic, J.; Stake, J.; Michael, E. A.

    2010-03-01

    More efficient continuous-wave photonic near-infrared mixers as terahertz sources are investigated with the motivation to develop a universal photonic local oscillator for astronomical submillimeter/terahertz receiver systems. For this, our group has developed new concepts for vertically illuminated traveling-wave (TW) photomixers. The new device called TW-Uni-Travelling Carrier photodiodes (TW-UTC PD) was simulated, modeled and shall be optical/terahertz tested at the Electrical Engineering Department of the University of Chile, whereas device fabrication is performed at the MC2 cleanroom facility at Chalmers University of technology. We are reporting on first progresses in this direction.

  5. Structured IR illumination for relative depth sensing in virtual interfaces

    NASA Astrophysics Data System (ADS)

    Kress, Bernard; Raulot, Victorien; Grossman, Michel

    2012-06-01

    Depth mapping or depth sensing has become a popular field, applied not only to automotive sensing for collision avoidance (radar) but also to gesture sensing for gaming and virtual interfaces (optical). Popular gesture sensing devices such as the Kinect from Microsoft's Xbox gaming device produce a full absolute depth map, which is in most cases not adapted to the task on hand (relative gesture sensing). We propose in this paper a new gesture sensing technique through structured IR illumination to provide a relative depth mapping rather than an absolute one, and this reducing the requirements on computing power and therefore enabling this technology for wearable computing such as see through display.

  6. Light induced modulation instability of surfaces under intense illumination

    SciTech Connect

    Burlakov, V. M. Goriely, A.; Foulds, I.

    2013-12-16

    We show that a flat surface of a polymer in rubber state illuminated with intense electromagnetic radiation is unstable with respect to periodic modulation. Initial periodic perturbation is amplified due to periodic thermal expansion of the material heated by radiation. Periodic heating is due to focusing-defocusing effects caused by the initial surface modulation. The surface modulation has a period longer than the excitation wavelength and does not require coherent light source. Therefore, it is not related to the well-known laser induced periodic structures on polymer surfaces but may contribute to their formation and to other phenomena of light-matter interaction.

  7. Near spherical illumination of ion-beam and laser targets

    SciTech Connect

    Mark, J.W.K.

    1985-12-12

    A procedure is developed for reducing energy-deposition asymmetry in spherical targets driven directly by ion or laser beams. This work is part of a strategy for achieving illumination symmetry in such targets, which is proposed as an alternative to those in the literature. This strategy allows an axially symmetric placement of beamlets, which would be convenient for some driven or reactor scenarios. It also allows the use of beam currents or energy fluxes and beam transverse profiles to help reduce deposition asymmetry with fewer beamlets. In the ideal limit of thin deposition layers and controlled beam profiles, at most six beamlets are needed for target symmetry.

  8. Pathogens and polymers: Microbe–host interactions illuminate the cytoskeleton

    PubMed Central

    Haglund, Cat M.

    2011-01-01

    Intracellular pathogens subvert the host cell cytoskeleton to promote their own survival, replication, and dissemination. Study of these microbes has led to many discoveries about host cell biology, including the identification of cytoskeletal proteins, regulatory pathways, and mechanisms of cytoskeletal function. Actin is a common target of bacterial pathogens, but recent work also highlights the use of microtubules, cytoskeletal motors, intermediate filaments, and septins. The study of pathogen interactions with the cytoskeleton has illuminated key cellular processes such as phagocytosis, macropinocytosis, membrane trafficking, motility, autophagy, and signal transduction. PMID:21969466

  9. Light-beam evolution in slant illumination of turbid medium

    NASA Astrophysics Data System (ADS)

    Aistov, A. V.; Gavrilenko, V. G.

    1993-08-01

    The space and angle distributions of the radiation intensity in an absorbing anisotropically scattering medium are examined for slant illumination of the boundary by a limited beam. An analytic solution of the transport equation in a small-angle approximation is compared with Monte Carlo modeling of light propagation in sea water. The existence of a depth region in which the variances of the space and angle intensity distributions rise anomalously rapidly due to the presence of absorption and the asymmetry of the problem is pointed out.

  10. Redundant information from thermal illumination: quantum Darwinism in scattered photons

    NASA Astrophysics Data System (ADS)

    Jess Riedel, C.; Zurek, Wojciech H.

    2011-07-01

    We study quantum Darwinism, the redundant recording of information about the preferred states of a decohering system by its environment, for an object illuminated by a blackbody. We calculate the quantum mutual information between the object and its photon environment for blackbodies that cover an arbitrary section of the sky. In particular, we demonstrate that more extended sources have a reduced ability to create redundant information about the system, in agreement with previous evidence that initial mixedness of an environment slows—but does not stop—the production of records. We also show that the qualitative results are robust for more general initial states of the system.

  11. Restoration of uneven illumination in light sheet microscopy images.

    PubMed

    Uddin, Mohammad Shorif; Lee, Hwee Kuan; Preibisch, Stephan; Tomancak, Pavel

    2011-08-01

    Light microscopy images suffer from poor contrast due to light absorption and scattering by the media. The resulting decay in contrast varies exponentially across the image along the incident light path. Classical space invariant deconvolution approaches, while very effective in deblurring, are not designed for the restoration of uneven illumination in microscopy images. In this article, we present a modified radiative transfer theory approach to solve the contrast degradation problem of light sheet microscopy (LSM) images. We confirmed the effectiveness of our approach through simulation as well as real LSM images.

  12. Efficient cultural heritage image restoration with nonuniform illumination enhancement

    NASA Astrophysics Data System (ADS)

    Jmal, Marwa; Souidene, Wided; Attia, Rabah

    2017-01-01

    Cultural heritage digitization has been of research interest for several decades. For such, the quality of the stored images should be pleasant to see. However, as images captured by digital devices may include undesirable effects, conducting an enhancement on the image is essential. In this context, we present a framework for the purpose of cultural heritage image illumination enhancement. First, a mapping curve based on saturation feedback is created to adjust the contrast. Then illumination is enhanced by applying a modified homomorphic filter in the frequency domain. The technique employs an optimization search process based on the efficient golden section search algorithm to compute the optimal parameters to produce the enhanced image. Finally, a color restoration function is applied to overcome the problem of color violation. The resulted image represents a trade-off among local contrast improvement, detail enhancement, and preserving the naturalness of the image. Experiments are conducted on a collected dataset of cultural heritage images and compared to some of the state-of-the-art image enhancement methods using a set of quantitative assessments criteria. Results have shown that our proposed approach is able to accomplish a wide set of the performance goals.

  13. Fast structured illumination microscopy using rolling shutter cameras

    NASA Astrophysics Data System (ADS)

    Song, Liyan; Lu-Walther, Hui-Wen; Förster, Ronny; Jost, Aurélie; Kielhorn, Martin; Zhou, Jianying; Heintzmann, Rainer

    2016-05-01

    Spatial light modulators (SLM) update in a synchronous manner, whereas the data readout process in fast structured illumination systems is usually done using a rolling shutter camera with asynchronous readout. In structured illumination microscopy (SIM), this leads to synchronization problems causing a speed limit for fast acquisition. In this paper we present a configuration to overcome this limit by exploiting the extremely fast SLM display and dividing it into several segments along the direction of the rolling shutter of the sCMOS camera and displaying multiple SLM frames per camera acquisition. The sCMOS runs in continuous rolling shutter mode and the SLM keeps the readout-line always inside a dark region presenting different SIM patterns before and after the readout/start-exposure line. Using this approach, we reached a raw frame rate of 714 frames per second (fps) resulting in a two-beam SIM acquisition rate of 79 fps with a region of interest (ROI) of 16.5  ×  16.5 μm2.

  14. Optical characterization for off-axis illumination in DLP system

    NASA Astrophysics Data System (ADS)

    Zhuang, Zhenfeng; Chen, Enguo; Qu, Bixiang; Yu, Feihong

    2012-10-01

    Matrix optics is a general method to research and calculate geometric optical properties. Based on the principle of image formation for paraxial rays in geometrical optics, the ray tracing matrix properties of an illumination in Digital Light Processing (DLP) system are derived by ABCD matrix method for paraxial optics and optical elements is considered as thin-lens approximation, including fly-eye lens array, relay lens and TIR prisms. Through the theory analysis according to the transfer matrix, dual-face fly-eye lens array is measured as a function to change beam angle instead of beam characteristics, which is compared with single-face fly-eye lens. Consequently, the second surface of dual-face fly-eye lens can be seen as a field lens which can reduce the relay system diameter. In addition, it has been found that the TIR prisms generate magnification astigmatism and different angle magnification in meridian plane and sagittal plane, when the light beam transmits the TIR prisms, and could not be ignored in the DLP system design. Thus, a novel off-axis illumination system which employed a cylindrical lens is developed. The research indicates that the imagery quality of relay lens system is ideal, and the novel system can solve the difficult problems about astigmatism and angle magnification.

  15. Three-dimensional illumination system for tomographic particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Zhang, Fen; Song, Yang; Qu, Xiangju; Ji, Yunjing; Li, Zhenhua; He, Anzhi

    2016-10-01

    Tomographic particle image velocimetry (Tomo-PIV) is a new developed technique for three-component threedimensional (3C-3D) velocity measurement of the flow field based on the optical tomographic reconstruction method, and has been received extensive attention of the related industries. Three-dimensional light source illuminating the tracer particles of flow field is a critical application for tomographic particle image velocimetry. Three-dimensional light source not only determines the size of measurement volume and the range of the scope of application, but also has a great influence on the image quality. In this work, we propose a rectangular light amplification system using powell lens, prisms and two reflectors. The system can be optimized if given the system parameters based on the theoretical model. The rectangular light amplification system will be verified experimentally by measuring the cross section size of the illuminated light source. A 60mm×25mm cross section of rectangular three-dimensional light source can be obtained by using the rectangular light amplification system. The experiments demonstrate the the feasibility the proposed system.

  16. Vertically illuminated TW-UTC photodiodes for terahertz generation

    NASA Astrophysics Data System (ADS)

    Barrientos Z., Claudio M.; Calle G., Victor H.; Alvarez, Jaime A.; Mena, F. Patricio; Vukusic, Josip; Stake, Jan; Michael, Ernest A.

    2012-09-01

    More efficient and powerful continuous-wave photonic mixers as terahertz sources are motivated by the need of more versatile local oscillators for submillimeter/terahertz receiver systems. Uni-Travelling Carrier (UTC) photodiodes are very prospective candidates for reaching this objective, but so far only have been reported as lumped-elements or as edge-illuminated optical-waveguide travelling-wave (TW) devices. To overcome the associated power limitations of those implementations, we are developing a novel implementation of the UTC photodiodes which combines a travelingwave photomixer with vertical velocity-matched illumination in a distributed structure. In this implementation called velocity-matched travelling-wave uni-travelling carrier photodiode, it is possible to obtain in-situ velocity matching of the beat-fringes of the two angled laser beams with the submm/THz-wave on the stripline. In this way, minimum frequency roll-off is achieved by tuning the angle between the two laser beams. A first design of these TW-UTC PDs from our Terahertz Photonics Laboratory at University of Chile has been micro-fabricated at the MC2 cleanroom facility at Chalmers Technical University.

  17. How Direction of Illumination Affects Visually Perceived Surface Roughness

    PubMed Central

    Ho, Yun-Xian; Landy, Michael S.; Maloney, Laurence T.

    2009-01-01

    We examined visual estimation of surface roughness using random computer-generated three-dimensional (3D) surfaces rendered under a mixture of diffuse lighting and a punctate source. The angle between the tangent to the plane containing the surface texture and the direction to the punctate source was varied from 50 to 70 degrees across lighting conditions. Observers were presented with pairs of surfaces under different lighting conditions and indicated which 3D surface appeared rougher. Surfaces were viewed either in isolation or in scenes with added objects whose shading, cast shadows and specular highlights provided information about the spatial distribution of illumination. All observers perceived surfaces to be markedly rougher with decreasing illuminant angle. Performance in scenes with added objects was no closer to constant than that in scenes without added objects. We identified four novel cues that are valid cues to roughness under any single lighting condition but that are not invariant under changes in lighting condition. We modeled observers’ deviations from roughness constancy as a weighted linear combination of these “pseudo-cues” and found that they account for a substantial amount of observers’ systematic deviations from roughness constancy with changes in lighting condition. PMID:16881794

  18. QR code optical encryption using spatially incoherent illumination

    NASA Astrophysics Data System (ADS)

    Cheremkhin, P. A.; Krasnov, V. V.; Rodin, V. G.; Starikov, R. S.

    2017-02-01

    Optical encryption is an actively developing field of science. The majority of encryption techniques use coherent illumination and suffer from speckle noise, which severely limits their applicability. The spatially incoherent encryption technique does not have this drawback, but its effectiveness is dependent on the Fourier spectrum properties of the image to be encrypted. The application of a quick response (QR) code in the capacity of a data container solves this problem, and the embedded error correction code also enables errorless decryption. The optical encryption of digital information in the form of QR codes using spatially incoherent illumination was implemented experimentally. The encryption is based on the optical convolution of the image to be encrypted with the kinoform point spread function, which serves as an encryption key. Two liquid crystal spatial light modulators were used in the experimental setup for the QR code and the kinoform imaging, respectively. The quality of the encryption and decryption was analyzed in relation to the QR code size. Decryption was conducted digitally. The successful decryption of encrypted QR codes of up to 129  ×  129 pixels was demonstrated. A comparison with the coherent QR code encryption technique showed that the proposed technique has a signal-to-noise ratio that is at least two times higher.

  19. Spatially multiplexed interferometric microscopy with partially coherent illumination

    NASA Astrophysics Data System (ADS)

    Picazo-Bueno, José Ángel; Zalevsky, Zeev; García, Javier; Ferreira, Carlos; Micó, Vicente

    2016-10-01

    We have recently reported on a simple, low cost, and highly stable way to convert a standard microscope into a holographic one [Opt. Express 22, 14929 (2014)]. The method, named spatially multiplexed interferometric microscopy (SMIM), proposes an off-axis holographic architecture implemented onto a regular (nonholographic) microscope with minimum modifications: the use of coherent illumination and a properly placed and selected one-dimensional diffraction grating. In this contribution, we report on the implementation of partially (temporally reduced) coherent illumination in SMIM as a way to improve quantitative phase imaging. The use of low coherence sources forces the application of phase shifting algorithm instead of off-axis holographic recording to recover the sample's phase information but improves phase reconstruction due to coherence noise reduction. In addition, a less restrictive field of view limitation (1/2) is implemented in comparison with our previously reported scheme (1/3). The proposed modification is experimentally validated in a regular Olympus BX-60 upright microscope considering a wide range of samples (resolution test, microbeads, swine sperm cells, red blood cells, and prostate cancer cells).

  20. Exomoon Habitability Constrained by Illumination and Tidal Heating

    PubMed Central

    2013-01-01

    Abstract The detection of moons orbiting extrasolar planets (“exomoons”) has now become feasible. Once they are discovered in the circumstellar habitable zone, questions about their habitability will emerge. Exomoons are likely to be tidally locked to their planet and hence experience days much shorter than their orbital period around the star and have seasons, all of which works in favor of habitability. These satellites can receive more illumination per area than their host planets, as the planet reflects stellar light and emits thermal photons. On the contrary, eclipses can significantly alter local climates on exomoons by reducing stellar illumination. In addition to radiative heating, tidal heating can be very large on exomoons, possibly even large enough for sterilization. We identify combinations of physical and orbital parameters for which radiative and tidal heating are strong enough to trigger a runaway greenhouse. By analogy with the circumstellar habitable zone, these constraints define a circumplanetary “habitable edge.” We apply our model to hypothetical moons around the recently discovered exoplanet Kepler-22b and the giant planet candidate KOI211.01 and describe, for the first time, the orbits of habitable exomoons. If either planet hosted a satellite at a distance greater than 10 planetary radii, then this could indicate the presence of a habitable moon. Key Words: Astrobiology—Extrasolar planets—Habitability—Habitable zone—Tides. Astrobiology 13, 18–46. PMID:23305357

  1. Laser illumination of multiple capillaries that form a waveguide

    DOEpatents

    Dhadwal, Harbans S.; Quesada, Mark A.; Studier, F. William

    1998-08-04

    A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis.

  2. Laser illumination of multiple capillaries that form a waveguide

    DOEpatents

    Dhadwal, H.S.; Quesada, M.A.; Studier, F.W.

    1998-08-04

    A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis. 35 figs.

  3. Pulmonary decontamination for photodynamic inactivation with extracorporeal illumination

    NASA Astrophysics Data System (ADS)

    Geralde, Mariana C.; Leite, Ilaiáli S.; Inada, Natalia M.; Grecco, Clóvis; Medeiros, Alexandra I.; Kurachi, Cristina; Bagnato, Vanderlei S.

    2014-03-01

    Infectious pneumonia is a major cause of morbidity and mortality, despite advances in diagnostics and therapeutics in pulmonary infections. One of the major difficulties associated with the infection comes from the high rate of antibiotic resistant microorganisms, claiming for the use of alternative techniques with high efficiency and low cost. The photodynamic inactivation (PDI) is emerging as one of the great possibilities in this area, once its action is oxidative, not allowing microorganism develops resistance against the treatment. PDI for decontamination pulmonary has potential for treatment or creating better conditions for the action of antibiotics. In this study, we are developing a device to implement PDI for the treatment of lung diseases with extracorporeal illumination. To validate our theory, we performed measurements in liquid phantom to simulate light penetration in biological tissues at various fluency rates, the temperature was monitored in a body of hairless mice and the measurements of light transmittance in this same animal model. A diode laser emitting at 810 nm in continuous mode was used. Our results show 70% of leakage at 0.5 mm of thickness in phantom model. The mouse body temperature variation was 5.4 °C and was observed light transmittance through its chest. These results are suggesting the possible application of the extracorporeal illumination using infrared light source. Based on these findings, further studies about photodynamic inactivation will be performed in animal model using indocyanine green and bacteriochlorin as photosensitizers. The pulmonary infection will be induced with Streptococcus pneumoniae and Klebsiella pneumoniae.

  4. Fast rendering of forest ecosystems with dynamic global illumination

    NASA Astrophysics Data System (ADS)

    Steele, Jay Edward

    Real-time rendering of large-scale, forest ecosystems remains a challenging problem, in that important global illumination effects, such as leaf transparency and inter-object light scattering, are difficult to capture, given tight timing constraints and scenes that typically contain hundreds of millions of primitives. We propose a new lighting model, adapted from a model previously used to light convective clouds and other participating media, together with GPU ray tracing, in order to achieve these global illumination effects while maintaining near real-time performance. The lighting model is based on a lattice-Boltzmann method in which reflectance, transmittance, and absorption parameters are taken from measurements of real plants. The lighting model is solved as a preprocessing step, requires only seconds on a single GPU, and allows dynamic lighting changes at run-time. The ray tracing engine, which runs on one or multiple GPUs, combines multiple acceleration structures to achieve near real-time performance for large, complex scenes. Both the preprocessing step and the ray tracing engine make extensive use of NVIDIA's Compute Unified Device Architecture (CUDA).

  5. Evanescent field shapes excitation profile under axial epi-illumination

    PubMed Central

    2012-01-01

    Abstract. Axial epi-illuminating light transmitting a >1.3-numerical-aperture microscope objective creates an excitation volume at focus with size and shape dictated by diffraction and due to refraction by the objective and by the coverslip interface separating a specimen in aqueous buffer from the oil immersion objective. The evanescent field on the coverslip aqueous side affects primarily the excitation volume axial dimension as the specimen in focus approaches the interface to within a few hundred nanometers. Following excitation, an excited stationary dipole moment emits fluorescence in a spatially varying pattern collected over the large objective aperture. Collected light propagates in parallel rays toward the tube lens that forms a real three-dimensional image that is decoded to identify dipole orientation. An integral representation of the excitation and emitted fields for infinity-corrected optics—including effects of finite conjugate illumination, fluorescence emission near an interface, emitter dipole orientation, spherical aberration, light transmission through a dichroic filter, and for real microscopic specifications—accurately models observed field intensities including the substantial excitation from the evanescent field. The goal is to develop and verify the practical depiction of excitation and emission in a real microscope for quantitative interpretation of the 3-D emission pattern. PMID:22734777

  6. Illumination robust change detection with CMOS imaging sensors

    NASA Astrophysics Data System (ADS)

    Rengarajan, Vijay; Gupta, Sheetal B.; Rajagopalan, A. N.; Seetharaman, Guna

    2015-05-01

    Change detection between two images in the presence of degradations is an important problem in the computer vision community, more so for the aerial scenario which is particularly challenging. Cameras mounted on moving platforms such as aircrafts or drones are subject to general six-dimensional motion as the motion is not restricted to a single plane. With CMOS cameras increasingly in vogue due to their low power consumption, the inevitability of rolling-shutter (RS) effect adds to the challenge. This is caused by sequential exposure of rows in CMOS cameras unlike conventional global shutter cameras where all pixels are exposed simultaneously. The RS effect is particularly pronounced in aerial imaging since each row of the imaging sensor is likely to experience a different motion. For fast-moving platforms, the problem is further compounded since the rows are also affected by motion blur. Moreover, since the two images are shot at different times, illumination differences are common. In this paper, we propose a unified computational framework that elegantly exploits the scarcity constraint to deal with the problem of change detection in images degraded by RS effect, motion blur as well as non-global illumination differences. We formulate an optimization problem where each row of the distorted image is approximated as a weighted sum of the corresponding rows in warped versions of the reference image due to camera motion within the exposure period to account for geometric as well as photometric differences. The method has been validated on both synthetic and real data.

  7. Exomoon habitability constrained by illumination and tidal heating.

    PubMed

    Heller, René; Barnes, Rory

    2013-01-01

    The detection of moons orbiting extrasolar planets ("exomoons") has now become feasible. Once they are discovered in the circumstellar habitable zone, questions about their habitability will emerge. Exomoons are likely to be tidally locked to their planet and hence experience days much shorter than their orbital period around the star and have seasons, all of which works in favor of habitability. These satellites can receive more illumination per area than their host planets, as the planet reflects stellar light and emits thermal photons. On the contrary, eclipses can significantly alter local climates on exomoons by reducing stellar illumination. In addition to radiative heating, tidal heating can be very large on exomoons, possibly even large enough for sterilization. We identify combinations of physical and orbital parameters for which radiative and tidal heating are strong enough to trigger a runaway greenhouse. By analogy with the circumstellar habitable zone, these constraints define a circumplanetary "habitable edge." We apply our model to hypothetical moons around the recently discovered exoplanet Kepler-22b and the giant planet candidate KOI211.01 and describe, for the first time, the orbits of habitable exomoons. If either planet hosted a satellite at a distance greater than 10 planetary radii, then this could indicate the presence of a habitable moon.

  8. CauStereo: structure from underwater flickering illumination

    NASA Astrophysics Data System (ADS)

    Swirski, Yohay; Schechner, Yoav Y.

    2012-10-01

    Underwater, in littoral zones, natural illumination typically varies strongly temporally and spatially. Waves on the water surface refract light into the water in spatiotemporal varying intensity. The resulting underwater illumination field forms a caustic network and is known as flicker. Studies in underwater computer vision typically consider flicker to be an undesired effect. In contrast, recent studies1-3 show that the spatiotemporally varying caustic network can be useful for stereoscopic vision, naturally leading to range mapping of the scene. In this paper, we survey these studies. Range triangulation by stereoscopic vision requires the determination of correspondence between image points in different viewpoints. This is typically a difficult problem. However, the spatiotemporal caustic pattern effectively encodes stereo correspondences. Thus, the use of this effect is termed2 CauStereo. The temporal radiance variations due to flicker are unique to each object point. Thus, correspondence of image points per object point becomes unambiguous. A variational optimization formulation is used in practice to find the dense stereo correspondence field. This formulation helps overcome uncertain regions (e.g., due to shadows) and shortens the acquisition time. Limitations of the approach are revealed by ray-tracing simulations. The method was demonstrated by underwater field experiments.2

  9. Influence of illumination on autonomic thermoregulation and choice of clothing

    NASA Astrophysics Data System (ADS)

    Kim, Seung Hi; Jeong, Woon Seon

    2002-04-01

    This study was conducted to investigate how different levels of illumination below 1,000 lx would affect the autonomic and behavioral temperature regulation of humans. Seven healthy college-aged women (20+/-0 years) volunteered to participate in this study. They were exposed to a temperature of 26 °C in 320 lx for 30 min ('Equilibrium') followed by 700 lx or 70 lx for 30 min (stage 1). After stage 1, they were exposed to 20 °C for 30 min in the same illumination as in stage 1 (stage 2). In stage 2 the subjects were instructed to select and wear the clothing they needed for their thermal comfort. The data obtained were analyzed by paired t-test and repeated measures of analysis of variance. Forearm skin blood flow tended to remain steady in 700 lx but decreased markedly in 70 lx in stage 1. There were no significant differences between subjective thermal responses of the subjects experiencing 700 lx or 70 lx in both stages although the subjects felt cooler in stage 2 than in stage 1. The subjects were likely to prefer wearing heavier clothing in 70 lx than in 700 lx. It was concluded that vasoconstriction in the upper limbs occurred more strongly in dim light, which might result in different clothing preferences in a cool environment from those associated with brighter light intensity.

  10. Photochromic film texturing with speckle illumination: application to goods authentication

    NASA Astrophysics Data System (ADS)

    Crespo-Monteiro, Nicolas; Destouches, Nathalie; Fournel, Thierry

    2012-10-01

    Thanks to the localized surface plasmon resonance of silver nanoparticles, mesoporous titania films loaded with silver salts manifest a photochromic behavior that can be used to perform updatable laser microinscriptions. Under UV illumination, the silver salts are reduced into silver nanoparticles and the illuminated areas become grey-brown. This coloration can be completely erased by oxidizing the silver nanoparticles with a polychromatic or monochromatic visible light whose spectrum lies in the resonance band of silver nanoparticles. The paper investigates the usage of such photochromic Ag/TiO2 films for creating an updatable random texturing. Random textures are produced on coated glass samples, initially homogeneous, by exposing them to speckle patterns resulting from the scattering of a UV laser beam from an optically rough surface. The stability of such textures under homogeneous UV post-exposures is investigated as a function of the speckle exposure time. Under optimized exposure conditions, the textures remain stable enough for a long time and the differences between textures are sufficiently discriminative to use the texturing process for goods authentication. This is demonstrated by calculating the correlation coefficient of thousands of couples of texture images. The numerical treatment of images has the advantage to be robust to changes in the sample repositioning between different image records. The rewritability of the samples is characterized through the comparison of different textures successively erased and written at the same place on multiple samples.

  11. Perceived glossiness and lightness under real-world illumination

    PubMed Central

    Olkkonen, K. Maria; Brainard, David H.

    2010-01-01

    Color, lightness, and glossiness are perceptual attributes associated with object reflectance. For these perceptual representations to be useful, they must correlate with physical reflectance properties of objects, and not be overly affected by changes in illumination or the viewing context. Color and lightness constancy have received much attention in past investigations, but little is known about the perception of glossiness under changing lighting conditions. We employed a matching paradigm to investigate the perception of lightness and glossiness under geometric changes in illumination. Stimuli were computer simulations of scenes with spheres displayed on a high-dynamic-range display. Observers matched the specular and diffuse reflectance of a test sphere to match the appearance of a reference sphere simulated under a different light field. Observers were veridical in their diffuse component matches across geometric changes in light fields. In contrast, surface specularity was either overestimated or underestimated relative to the reference sphere depending on the light field comparison. The effect of changing light field geometry on perceived glossiness and lightness was independent of surface diffuse and specular reflectance and approximately independent of the roughness of the specular component. Luminance histogram statistics (standard deviation, skewness, kurtosis) were not good predictors of the specular component matches. PMID:20884603

  12. Directed energy active illumination for near-Earth object detection

    NASA Astrophysics Data System (ADS)

    Riley, Jordan; Lubin, Philip; Hughes, Gary B.; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Bible, Johanna; Johansson, Isabella E.; Griswold, Janelle; Cook, Brianna

    2014-09-01

    On 15 February 2013, a previously unknown ~20 m asteroid struck Earth near Chelyabinsk, Russia, releasing kinetic energy equivalent to ~570 kt TNT. Detecting objects like the Chelyabinsk impactor that are orbiting near Earth is a difficult task, in part because such objects spend much of their own orbits in the direction of the Sun when viewed from Earth. Efforts aimed at protecting Earth from future impacts will rely heavily on continued discovery. Ground-based optical observatory networks and Earth-orbiting spacecraft with infrared sensors have dramatically increased the pace of discovery. Still, less than 5% of near-Earth objects (NEOs) >=100 m/~100 Mt TNT have been identified, and the proportion of known objects decreases rapidly for smaller sizes. Low emissivity of some objects also makes detection by passive sensors difficult. A proposed orbiting laser phased array directed energy system could be used for active illumination of NEOs, enhancing discovery particularly for smaller and lower emissivity objects. Laser fiber amplifiers emit very narrow-band energy, simplifying detection. Results of simulated illumination scenarios are presented based on an orbiting emitter array with specified characteristics. Simulations indicate that return signals from small and low emissivity objects is strong enough to detect. The possibility for both directed and full sky blind surveys is discussed, and the resulting diameter and mass limits for objects in different observational scenarios. The ability to determine both position and speed of detected objects is also discussed.

  13. Adaptive display luminance for viewing smartphones under low illuminance.

    PubMed

    Na, Nooree; Suk, Hyeon-Jeong

    2015-06-29

    The study investigates the optimal display luminance for viewing smartphones in conditions of low illuminance. This proposes a model of adaptive display in that display luminance changes gradually with the passage of watching time. It starts at a fairly low display luminance of 10 cd/m2, and after 10 seconds, the luminance increases slowly until it reaches 40 cd/m2 for 20 seconds and maintains the luminance. For the development of the model, an experiment was conducted to identify the optimal luminance for initial viewing and that for continuous viewing, as well as the change speed of display luminance. In order to validate the model, users' subjective judgments and activation of alpha rhythm were observed, and the result confirmed the superiority of the adaptive display luminance compared to the current display luminance in terms of physiological comfort and psychological satisfaction. It is expected that this study contributes to the pleasing use of displays at night under low illuminance by applying to diverse types of display devices.

  14. Highly Resolved Intravital Striped-illumination Microscopy of Germinal Centers

    PubMed Central

    Andresen, Volker; Sporbert, Anje

    2014-01-01

    Monitoring cellular communication by intravital deep-tissue multi-photon microscopy is the key for understanding the fate of immune cells within thick tissue samples and organs in health and disease. By controlling the scanning pattern in multi-photon microscopy and applying appropriate numerical algorithms, we developed a striped-illumination approach, which enabled us to achieve 3-fold better axial resolution and improved signal-to-noise ratio, i.e. contrast, in more than 100 µm tissue depth within highly scattering tissue of lymphoid organs as compared to standard multi-photon microscopy. The acquisition speed as well as photobleaching and photodamage effects were similar to standard photo-multiplier-based technique, whereas the imaging depth was slightly lower due to the use of field detectors. By using the striped-illumination approach, we are able to observe the dynamics of immune complex deposits on secondary follicular dendritic cells – on the level of a few protein molecules in germinal centers. PMID:24748007

  15. Bright illumination reduces parietal EEG alpha activity during a sustained attention task.

    PubMed

    Min, Byoung-Kyong; Jung, Young-Chul; Kim, Eosu; Park, Jin Young

    2013-11-13

    The influence of the illumination condition on our cognitive-performance seems to be more critical in the modern life, wherein, most people work in an office under a specific illumination condition. However, neurophysiological changes in a specific illumination state and their cognitive interpretation still remain unclear. Thereby, in the present study, the effect of different illumination conditions on the same cognitive performance was evaluated particularly by EEG wavelet analyses. During a sustained attention task, we observed that the higher illumination condition yielded significantly lower parietal tonic electroencephalogram (EEG) alpha activity before the presentation of the probe digit and longer reaction times, than that of the other illumination conditions. Although previous studies suggest that lower prestimulus EEG alpha activity is related to higher performance in an upcoming task, the reduced prestimulus alpha activity under higher illumination was associated with delayed reaction times in the present study. Presumably, the higher background illumination condition seems to be too bright for normal attentional processing and distracted participants' attention during a sustained attention task. Such a bottom-up effect by stimulus salience seemed to overwhelm a prestimulus top-down effect reflected in prestimulus alpha power during the bright background condition. This finding might imply a dynamic competition between prestimulus top-down and poststimulus bottom-up processes. Our findings provide compelling evidence that the illumination condition substantially modulates our attentional processing. Further refinement of the illumination parameters and subsequent exploration of cognitive-modulation are necessary to facilitate our cognitive performance.

  16. Plane parallel radiance transport for global illumination in vegetation

    SciTech Connect

    Max, N.; Mobley, C.; Keating, B.; Wu, E.H.

    1997-01-05

    This paper applies plane parallel radiance transport techniques to scattering from vegetation. The leaves, stems, and branches are represented as a volume density of scattering surfaces, depending only on height and the vertical component of the surface normal. Ordinary differential equations are written for the multiply scattered radiance as a function of the height above the ground, with the sky radiance and ground reflectance as boundary conditions. They are solved using a two-pass integration scheme to unify the two-point boundary conditions, and Fourier series for the dependence on the azimuthal angle. The resulting radiance distribution is used to precompute diffuse and specular `ambient` shading tables, as a function of height and surface normal, to be used in rendering, together with a z-buffer shadow algorithm for direct solar illumination.

  17. Direct illumination calibration of telescopes at the quantum precision limit

    NASA Astrophysics Data System (ADS)

    Barrelet, E.

    2016-10-01

    The electronic response of a telescope under direct illumination by a point-like light source is based on photon counting. With the data obtained using the SNDICE light source and the Megacam camera on the CFHT telescope, we show that the ultimate precision is only limited by the photon statistical fluctuation, which is below 1 ppm. A key feature of the analysis is the incorporation of diffuse light that interfers with specularly reflected light in the transmission model to explain the observed diffraction patterns. The effect of diffuse light, usually hidden conveniently in the Strehl ratio for an object at infinity, is characterized with a precision of 10 ppm. In particular, the spatial frequency representation provides some strong physical constraints and a practical monitoring of the roughness of various optical surfaces.

  18. Ideal illuminants for rod/L-cone color

    NASA Astrophysics Data System (ADS)

    McCann, John J.

    2006-01-01

    Humans see multicolor complex images with illuminants that have very low amounts of 400 to 580nm light when there is enough long-wave light greater than 590nm. Interactions between rods and long-wave (L) cones generate these colors. They are observed when there is insufficient light for a threshold response from M- and S-cones. This paper measures the spectral emission of a wood fire and a wax candle and it compares these low-color temperature spectral radiant exitances with the sensitivities of rods and long-wave cones. The paper reviews some of the literature on the evolution of human cone pigments and the early use of fire by hominids.

  19. Space power by laser illumination of PV arrays

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1991-01-01

    There has recently been a resurgence of interest in the use of beamed power to support space exploration activities. The utility is examined of photovoltaics and problem and research areas are identified for photovoltaics in two beamed-power applications: to convert incident laser radiation to power at a remote receiving station, and as a primary power source on space based power station transmitting power to a remote user. A particular application of recent interest is to use a ground-based free electron laser as a power source for space applications. Specific applications include: night power for a moonbase by laser illumination of the moonbase solar arrays; use of a laser to provide power for satellites in medium and geosynchronous Earth orbit, and a laser powered system for an electrical propulsion orbital transfer vehicle. These and other applications are currently being investigated at NASA Lewis as part of a new program to demonstrate the feasibility of laser transmission of power for space.

  20. Target tracking using infrared measurements and laser illumination

    NASA Astrophysics Data System (ADS)

    Maybeck, Peter S.; Herrera, Theodore D.; Evans, Roger J.

    1994-07-01

    A missile target tracker is designed using a filter/correlator (with adaptive target shape identification) based on forward-looking infrared (FLIR) sensor measurements to track the center-of-intensity of the hardbody/plume combination, and another filter using Doppler and/or speckle information in the return from a low-power laser illuminator to estimate the offset between the intensity centroid and the hardbody center-of-mass. The Doppler information is shown to yield smaller bias and error variance from the tracker than the speckle information. Performance of trackers based on just Doppler or both Doppler and speckle information from the laser return is portrayed as a function of important parameters in the tracking environment.

  1. Spectral image reconstruction by a tunable LED illumination

    NASA Astrophysics Data System (ADS)

    Lin, Meng-Chieh; Tsai, Chen-Wei; Tien, Chung-Hao

    2013-09-01

    Spectral reflectance estimation of an object via low-dimensional snapshot requires both image acquisition and a post numerical estimation analysis. In this study, we set up a system incorporating a homemade cluster of LEDs with spectral modulation for scene illumination, and a multi-channel CCD to acquire multichannel images by means of fully digital process. Principal component analysis (PCA) and pseudo inverse transformation were used to reconstruct the spectral reflectance in a constrained training set, such as Munsell and Macbeth Color Checker. The average reflectance spectral RMS error from 34 patches of a standard color checker were 0.234. The purpose is to investigate the use of system in conjunction with the imaging analysis for industry or medical inspection in a fast and acceptable accuracy, where the approach was preliminary validated.

  2. Chelators whose affinity for calcium is decreased by illumination

    NASA Technical Reports Server (NTRS)

    Tsien, Roger Y. (Inventor); Grynkiewicz, Grzegorz (Inventor); Minta, Akwasi (Inventor)

    1987-01-01

    The present invention discloses a group of calcium chelating compounds which have a descreased affinity for calcium following illumination. These new compounds contain a photolabile nitrobenzyl derivative coupled to a tetracarboxylate Ca.sup.2+ chelating parent compound having the octacoordinate chelating groups characteristic of EGTA or BAPTA. In a first form, the new compounds are comprised of a BAPTA-like chelator coupled to a single 2-nitrobenzyl derivative, which in turn is a photochemical precursor of a 2-nitrosobenzophenone. In a second form, the new compounds are comprised of a BAPTA-like chelator coupled to two 2-nitrobenzyl derivatives, themselves photochemical prcursors of the related 2-nitrosobenzophenones. The present invention also discloses a novel method for preparing 1-hydroxy- or 1-alkoxy-1-(2-nitroaryl)-1-aryl methanes. Methanes of this type are critical to the preparation of, or actually constitute, the photolabile Ca.sup.2+ chelating compounds disclosed and claimed herein.

  3. Illuminating the Decision Path: The Yucca Mountain Site Recommendation

    SciTech Connect

    Knox, E.; Slothouber, L.

    2003-02-25

    On February 14, 2002, U.S. Secretary of Energy Spencer Abraham provided to the President the ''Recommendation by the Secretary of Energy Regarding the Suitability of the Yucca Mountain Site for a Repository Under the Nuclear Waste Policy Act of 1982.'' This Recommendation, along with supporting materials, complied with statutory requirements for communicating a site recommendation to the President, and it did more: in 49 pages, the Recommendation also spoke directly to the Nation, illuminating the methodology and considerations that led toward the decision to recommend the site. Addressing technical suitability, national interests, and public concerns, the Recommendation helped the public understand the potential risks and benefits of repository development and placed those risks and benefits in a meaningful national context.

  4. Imaging of Phase Objects using Partially Coherent Illumination

    SciTech Connect

    Ravizza, F. L.

    2013-01-01

    Screening high-power laser optics for light intensifying phase objects that cause laserinduced damage on downstream optics is critical to sustaining laser operation. Identifying such flaws on large-apertures is quite challenging since they are relatively small and invisible to conventional inspection methods. A Linescan Phase Differential Imaging (LPDI) system was developed to rapidly identify these flaws on large-aperture optics within a single full-aperture dark-field image. We describe a two-step production phase object screening process consisting of LPDI mapping and image analysis, followed by high-resolution interferometry and propagation based evaluation of the downstream damage potential of identified flaws. An image simulation code capable of modeling the LPDI partially coherent illumination was used to optimize its phase object sensitivity.

  5. Multiple-lamp illumination system for projection displays

    NASA Astrophysics Data System (ADS)

    Vanderwerf, Dennis F.

    1996-03-01

    This paper describes a diascopic projection system that efficiently combines and integrates the output from multiple light sources. The images of these light sources are superposed at a common focus in the projection lens, resulting in a projected screen brightness considerably greater than that produced by a single lamp of equivalent wattage. The illumination system consists of a series of collimating and converging plastic Fresnel lenses, and a linear beam- integrating micro-prismatic element. Glass anamorphic condenser optics are also used. The optics can be cascaded, and the design requirements of a four-lamp system is described. The experimental results from a laboratory developed overhead projection system using dual tungsten-halogen lamps is discussed.

  6. Volume-based indirect illumination with irradiance decomposition

    NASA Astrophysics Data System (ADS)

    Li, Ruirui; Qin, Kaihuai

    2014-04-01

    This paper proposes a fast and accurate algorithm for indirect illumination. It uses volumes of different resolutions to sample and cache the geometric information and the secondary lights. By dividing the irradiance into two parts, it treats the lights coming from the far-field and that coming from the near-field differently. For the far-field ones, it propagates sphere harmonic represented lights on coarse voxels. For the near-field ones, it shoots rays and collects their contributions on fine voxels. By doing this, the algorithm in this paper avoids using many rays to march long distance. In the experiments, it renders about ten times faster than the VGI algorithm to get the same image qualities, especially for the large and complex scenes. Meanwhile, it further accelerates the rendering by inventing an incremental multi-resolution gathering. The experiments illustrate fast and accurate indirect light effects.

  7. Magnetoresistance in organic light-emitting diode structures under illumination

    NASA Astrophysics Data System (ADS)

    Desai, P.; Shakya, P.; Kreouzis, T.; Gillin, W. P.

    2007-12-01

    We have investigated the effect of illumination on the organic magnetoresistance (OMR) in organic light-emitting diode (OLED) structures. The results show that it is possible to obtain OMR at voltages below “turn-on,” where no OMR was visible for devices operated in the dark. The photoinduced OMR has a field dependence that is identical to that obtained for OLEDs containing very thin layers, where triplet dissociation at the cathode was a major component of the OMR. At voltages around the open circuit voltage, where the current through the device is very small, very large OMRs of ˜300% can be observed. The results support our proposed model for organic magnetoresistance as being caused in part by the interaction of free carriers with triplet excitons within the device. The results suggest that the introduction of a low field magnet could provide a simple means of improving the efficiency of organic photovoltaic cells.

  8. Structured illumination for tomographic X-ray diffraction imaging.

    PubMed

    Greenberg, Joel A; Hassan, Mehadi; Krishnamurthy, Kalyani; Brady, David

    2014-02-21

    Tomographic imaging of the molecular structure of an object is important for a variety of applications, ranging from medical and industrial radiography to security screening. X-ray diffraction imaging is the preeminent technique for performing molecular analysis of large volumes. Here we propose and demonstrate a new measurement architecture to improve the source and detector efficiency for diffraction imaging. In comparison with previous techniques, our approach reduces the required overall scan time by 1-2 orders of magnitude, which makes possible real-time scanning of a broad range of materials over a large volume using a table-top setup. This method, which relies on structuring spatially the illumination incident on an object moving relative to the X-ray source, is compatible with existing systems and has the potential to significantly enhance performance in an array of areas, such as medical diagnostic imaging and explosives detection.

  9. Hacking commercial quantum cryptography systems by tailored bright illumination

    NASA Astrophysics Data System (ADS)

    Lydersen, Lars; Wiechers, Carlos; Wittmann, Christoffer; Elser, Dominique; Skaar, Johannes; Makarov, Vadim

    2010-10-01

    The peculiar properties of quantum mechanics allow two remote parties to communicate a private, secret key, which is protected from eavesdropping by the laws of physics. So-called quantum key distribution (QKD) implementations always rely on detectors to measure the relevant quantum property of single photons. Here we demonstrate experimentally that the detectors in two commercially available QKD systems can be fully remote-controlled using specially tailored bright illumination. This makes it possible to tracelessly acquire the full secret key; we propose an eavesdropping apparatus built from off-the-shelf components. The loophole is likely to be present in most QKD systems using avalanche photodiodes to detect single photons. We believe that our findings are crucial for strengthening the security of practical QKD, by identifying and patching technological deficiencies.

  10. A 3-D fluorescence imaging system incorporating structured illumination technology

    NASA Astrophysics Data System (ADS)

    Antos, L.; Emord, P.; Luquette, B.; McGee, B.; Nguyen, D.; Phipps, A.; Phillips, D.; Helguera, M.

    2010-02-01

    A currently available 2-D high-resolution, optical molecular imaging system was modified by the addition of a structured illumination source, OptigridTM, to investigate the feasibility of providing depth resolution along the optical axis. The modification involved the insertion of the OptigridTM and a lens in the path between the light source and the image plane, as well as control and signal processing software. Projection of the OptigridTM onto the imaging surface at an angle, was resolved applying the Scheimpflug principle. The illumination system implements modulation of the light source and provides a framework for capturing depth resolved mages. The system is capable of in-focus projection of the OptigridTM at different spatial frequencies, and supports the use of different lenses. A calibration process was developed for the system to achieve consistent phase shifts of the OptigridTM. Post-processing extracted depth information using depth modulation analysis using a phantom block with fluorescent sheets at different depths. An important aspect of this effort was that it was carried out by a multidisciplinary team of engineering and science students as part of a capstone senior design program. The disciplines represented are mechanical engineering, electrical engineering and imaging science. The project was sponsored by a financial grant from New York State with equipment support from two industrial concerns. The students were provided with a basic imaging concept and charged with developing, implementing, testing and validating a feasible proof-of-concept prototype system that was returned to the originator of the concept for further evaluation and characterization.

  11. Face recognition with illumination and pose variations using MINACE filters

    NASA Astrophysics Data System (ADS)

    Casasent, David; Patnaik, Rohit

    2005-10-01

    This paper presents the status of our present CMU face recognition work. We first present a face recognition system that functions in the presence of illumination variations. We then present initial results when pose variations are also considered. A separate minimum noise and correlation energy (MINACE) filter is synthesized for each person. Our concern is face identification and impostor (non-database face) rejection. Most prior face identification did not address impostor rejection. We also present results for face verification with impostor rejection. The MINACE parameter c trades-off distortion-tolerance (recognition) versus discrimination (impostor rejection) performance. We use an automated filter-synthesis algorithm to select c and to synthesize the MINACE filter for each person using a training set of images of that person and a validation set of a few faces of other persons; this synthesis ensures both good recognition and impostor rejection performance. No impostor data is present in the training or validation sets. The peak-tocorrelation energy ratio (PCE) metric is used as the match-score in both the filter-synthesis and test stages and we show that it is better than use of the correlation peak value. We use circular correlations in filter synthesis and in tests, since such filters require one-fourth the storage space and similarly fewer on-line correlation calculations compared to the use of linear correlation filters. All training set images are registered (aligned) using the coordinates of several facial landmarks to remove scale variations and tilt bias. We also discuss the proper handling of pose variations by either pose estimation or by transforming the test input to all reference poses. Our face recognition system is evaluated using images from the CMU Pose, Illumination, and Expression (PIE) database. The same set of MINACE filters and impostor faces are used to evaluate the performance of the face identification and verification systems.

  12. Ultraviolet illumination as an adjunctive aid in dental inspection.

    PubMed

    Hermanson, Arnold S; Bush, Mary A; Miller, Raymond G; Bush, Peter J

    2008-03-01

    Tooth-colored resin fillings have become increasingly popular as restorative materials. Their presence in the dentition presents a challenge to the clinician and the forensic odontologist, as detection of the fillings can be difficult both visually and radiographically. As they necessarily form part of the unique dentition of an individual, recognition of the resins is important for forensic identification. Alternative light sources have been used with success in various fields of forensic science. In recent years small LED flashlights emitting at specific wavelengths in the ultraviolet light (UV) range have been developed. Their low cost, small size, and ready availability makes their use practical in both forensic dental inspection and clinical settings. UV inspection is of interest because enamel, dentin and dental materials all have differing fluorescent properties when illuminated by UV light. It was one goal of this research to quantitatively assess the fluorescence properties of modern restorative resins in order to predict their behavior during inspection using UV illumination. The second goal was to demonstrate practical use of UV in dental inspection with examples of how different materials fluoresce. Quantitative measurements were obtained for optical emission wavelength and intensity for 15 modern resins using a spectrophotometer. Results indicated that resin brands fluoresce at different wavelengths and with varying intensities. Practical use and comparison of the flashlights revealed that the most useful excitation wavelengths for resin detection were in the UVA range (365 and 380 nm). Porcelain restorations and composite resin fillings exhibited different responses to these two wavelengths and thus use of both is recommended for forensic dental inspection.

  13. Mirror Illumination and Spillover Measurements of the Atacama Cosmology Telescope

    NASA Technical Reports Server (NTRS)

    Gallardo, Patricio; Dunner, Rolando; Wollack, Ed; Jerez-Hanckes, Carlos

    2012-01-01

    The Atacama Cosmology Telescope (ACT) is a 6 m telescope designed to map the Cosmic Microwave Background (CMB) simultaneously at 145 GHz, 220GHz and 280GHz, The receiver in ACT, the Millimeter Bolometer Array Camera, features 1000 TES bolometers in each band, The detector performance depends critically on the total optical loading, requiring the spmover contributions from the optics to be minimal. This inspired the use of a cold Lyot stop to limit the illumination of the primary and the use of guard rings surrounding the primary and secondary reflectors. Here, we present a direct measurement of the illumination aperture for both reflectors and of the attenuation level outside the main optical path. We used a 145 GHz, 1 m W source and a chopper wheel to produce a time-varying signal with a broad heam proflle, We sampled the response of the camera for different locations of the source, placed in front and beside the primary and secondary mirrors. The aperture of the primary was measured to be 5,72 plus or minus 0,17m in diameter (95 plus or minus 3% of its geometrical size), while the aperture of the secondary yielded 2 plus or minus 0.12m in diameter. Both apertures are consistent with the optical design. Comparing to previous measurements of the beam solid angle from planet observations, we estimate an optical efficiency of 72.3 plus or minus 4,8%. We found that the attenuation outside the primary aperture was -16 plus or minus 2dB, which is below the theoretical expectations, and -22 plus or minus 1 dB outside the secondary aperture, which is consistent with simulations. These results motivated the extension of the baffles surrounding the secondary mirror, with the following reduction in detector optical loading from 2,24 pW to 188pW.

  14. Enhanced retinal modeling for face recognition and facial feature point detection under complex illumination conditions

    NASA Astrophysics Data System (ADS)

    Cheng, Yong; Li, Zuoyong; Jiao, Liangbao; Lu, Hong; Cao, Xuehong

    2016-07-01

    We improved classic retinal modeling to alleviate the adverse effect of complex illumination on face recognition and extracted robust image features. Our improvements on classic retinal modeling included three aspects. First, a combined filtering scheme was applied to simulate functions of horizontal and amacrine cells for accurate local illumination estimation. Second, we developed an optimal threshold method for illumination classification. Finally, we proposed an adaptive factor acquisition model based on the arctangent function. Experimental results on the combined Yale B; the Carnegie Mellon University poses, illumination, and expression; and the Labeled Face Parts in the Wild databases show that the proposed method can effectively alleviate illumination difference of images under complex illumination conditions, which is helpful for improving the accuracy of face recognition and that of facial feature point detection.

  15. Generation of arbitrary freeform source shapes using advanced illumination systems in high-NA immersion scanners

    NASA Astrophysics Data System (ADS)

    Zimmermann, Jörg; Gräupner, Paul; Neumann, Jens T.; Hellweg, Dirk; Jürgens, Dirk; Patra, Michael; Hennerkes, Christoph; Maul, Manfred; Geh, Bernd; Engelen, Andre; Noordman, Oscar; Mulder, Melchior; Park, Sean; De Vocht, Joep

    2010-04-01

    The application of customized and freeform illumination source shapes is a key enabler for continued shrink using 193 nm water based immersion lithography at the maximum possible NA of 1.35. In this paper we present the capabilities of the DOE based Aerial XP illuminator and the new programmable FlexRay illuminator. Both of these advanced illumination systems support the generation of such arbitrarily shaped illumination sources. We explain how the different parts of the optical column interact in forming the source shape with which the reticle is illuminated. Practical constraints of the systems do not limit the capabilities to utilize the benefit of freeform source shapes vs. classic pupil shapes. Despite a different pupil forming mechanism in the two illuminator types, the resulting pupils are compatible regarding lithographic imaging performance so that processes can be transferred between the two illuminator types. Measured freeform sources can be characterized by applying a parametric fit model, to extract information for optimum pupil setup, and by importing the measured source bitmap into an imaging simulator to directly evaluate its impact on CD and overlay. We compare measured freeform sources from both illuminator types and demonstrate the good matching between measured FlexRay and DOE based freeform source shapes.

  16. On the illumination compensation of retinal images by means of the bidimensional empirical mode decomposition

    NASA Astrophysics Data System (ADS)

    Marrugo, Andrés. G.; Vargas, Raúl; Chirino, Melet; Millán, María. S.

    2015-12-01

    Retinal images are used for diagnostic purposes by ophthalmologists. However, despite controlled conditions in acquisition retinal images often suffer from non-uniform illumination which hinder their clinical use. In this work we propose the compensation of the illumination by modeling the intensity as a sum of non-stationary signals using bidimensional empirical mode decomposition (BEMD). We compare the estimation and compensation of the background illumination with a widely used technique based retinal image pixel classification. The proposed method has shown to provide a better estimation of the background illumination, particularly in complicated areas such as the optic disk (usually bright) and the periphery of fundus images (usually dim).

  17. PHOTOINDUCED CURRENTS IN CDZNTE CRYSTALS AS A FUNCTION OF ILLUMINATION WAVELENGTH

    SciTech Connect

    Teague, L.; Washington, A.; Duff, M.

    2012-04-23

    We report variations in the currents of CdZnTe semiconductor crystals during exposure to a series of light emitting diodes of various wavelengths ranging from 470 to 950 nm. The changes in the steady-state current of one CdZnTe crystal with and without illumination along with the time dependence of the illumination effects are discussed. Analysis of the de-trapping and transient bulk currents during and after optical excitation yield insight into the behaviour of charge traps within the crystal. Similar behaviour is observed for illumination of a second CdZnTe crystal suggesting that the overall illumination effects are not crystal dependent.

  18. Disparity map generation from illumination variant stereo images using efficient hierarchical dynamic programming.

    PubMed

    Borisagar, Viral H; Zaveri, Mukesh A

    2014-01-01

    A novel hierarchical stereo matching algorithm is presented which gives disparity map as output from illumination variant stereo pair. Illumination difference between two stereo images can lead to undesirable output. Stereo image pair often experience illumination variations due to many factors like real and practical situation, spatially and temporally separated camera positions, environmental illumination fluctuation, and the change in the strength or position of the light sources. Window matching and dynamic programming techniques are employed for disparity map estimation. Good quality disparity map is obtained with the optimized path. Homomorphic filtering is used as a preprocessing step to lessen illumination variation between the stereo images. Anisotropic diffusion is used to refine disparity map to give high quality disparity map as a final output. The robust performance of the proposed approach is suitable for real life circumstances where there will be always illumination variation between the images. The matching is carried out in a sequence of images representing the same scene, however in different resolutions. The hierarchical approach adopted decreases the computation time of the stereo matching problem. This algorithm can be helpful in applications like robot navigation, extraction of information from aerial surveys, 3D scene reconstruction, and military and security applications. Similarity measure SAD is often sensitive to illumination variation. It produces unacceptable disparity map results for illumination variant left and right images. Experimental results show that our proposed algorithm produces quality disparity maps for both wide range of illumination variant and invariant stereo image pair.

  19. Effect of Illumination on Ocular Status Modifications Induced by Short-Term 3D TV Viewing

    PubMed Central

    Chen, Yuanyuan; Xu, Aiqin; Jiang, Jian

    2017-01-01

    Objectives. This study aimed to compare changes in ocular status after 3D TV viewing under three modes of illumination and thereby identify optimal illumination for 3D TV viewing. Methods. The following measures of ocular status were assessed: the accommodative response, accommodative microfluctuation, accommodative facility, relative accommodation, gradient accommodative convergence/accommodation (AC/A) ratio, phoria, and fusional vergence. The observers watched 3D television for 90 minutes through 3D shutter glasses under three illumination modes: A, complete darkness; B, back illumination (50 lx); and C, front illumination (130 lx). The ocular status of the observers was assessed both before and after the viewing. Results. After 3D TV viewing, the accommodative response and accommodative microfluctuation were significantly changed under illumination Modes A and B. The near positive fusional vergence decreased significantly after the 90-minute 3D viewing session under each illumination mode, and this effect was not significantly different among the three modes. Conclusions. Short-term 3D viewing modified the ocular status of adults. The least amount of such change occurred with front illumination, suggesting that this type of illumination is an appropriate mode for 3D shutter TV viewing. PMID:28348893

  20. Solid-State Pressure-Tolerant Illumination for MBARI's Underwater Low-Light Imaging System

    NASA Astrophysics Data System (ADS)

    McBride, Lance R.; Scholfield, James T.

    2007-06-01

    A significant amount of energy is consumed by the typical illumination systems of underwater vehicles. Attempts to utilize more efficient LED illumination underwater have been unsuccessful because the light-emitting diodes (LEDs) were coupled to a standard imaging system and they were not able to generate enough light to adequately illuminate the scene. In cases where the LEDs were grouped together, to provide more scene illumination, the lighting assembly was inefficient in size. The recent availability of high intensity LEDs provides a way to produce efficient and adequate lighting from a compact assembly. This paper covers the development of a deep ocean assembly based on these high intensity LEDs.

  1. Photo-induced currents in CdZnTe crystals as a function of illumination wavelength

    NASA Astrophysics Data System (ADS)

    Teague, L. C.; L, Washington A., II; Duff, M. C.; Groza, M.; Buliga, V.; Burger, A.

    2012-03-01

    We report variations in the currents of CdZnTe semiconductor crystals during exposure to a series of light emitting diodes of various wavelengths ranging from 470 to 950 nm. The changes in the steady-state current of one CdZnTe crystal with and without illumination along with the time dependence of the illumination effects are discussed. Analysis of the de-trapping and transient bulk currents during and after optical excitation yield insight into the behaviour of charge traps within the crystal. Similar behaviour is observed for illumination of a second CdZnTe crystal suggesting that the overall illumination effects are not crystal dependent.

  2. The relationship between ambient illumination and psychological factors in viewing of display Images

    NASA Astrophysics Data System (ADS)

    Iwanami, Takuya; Kikuchi, Ayano; Kaneko, Takashi; Hirai, Keita; Yano, Natsumi; Nakaguchi, Toshiya; Tsumura, Norimichi; Yoshida, Yasuhiro; Miyake, Yoichi

    2009-01-01

    In this paper, we have clarified the relationship between ambient illumination and psychological factors in viewing of display images. Psychological factors were obtained by the factor analysis with the results of the semantic differential (SD) method. In the psychological experiments, subjects evaluated the impressions of displayed images with changing ambient illuminating conditions. The illumination conditions were controlled by a fluorescent ceiling light and a color LED illumination which was located behind the display. We experimented under two kinds of conditions. One was the experiment with changing brightness of the ambient illumination. The other was the experiment with changing the colors of the background illumination. In the results of the experiment, two factors "realistic sensation, dynamism" and "comfortable," were extracted under different brightness of the ambient illumination of the display surroundings. It was shown that the "comfortable" was improved by the brightness of display surroundings. On the other hand, when the illumination color of surroundings was changed, three factors "comfortable," "realistic sensation, dynamism" and "activity" were extracted. It was also shown that the value of "comfortable" and "realistic sensation, dynamism" increased when the display surroundings were illuminated by the average color of the image contents.

  3. Seeing the light: illumination as a contextual cue to color choice behavior in bumblebees.

    PubMed

    Lotto, R Beau; Chittka, Lars

    2005-03-08

    The principal challenge faced by any color vision system is to contend with the inherent ambiguity of stimulus information, which represents the interaction between multiple attributes of the world (e.g., object reflectance and illumination). How natural systems deal with this problem is not known, although traditional hypotheses are predicated on the idea that vision represents object reflectance accurately by discounting early in processing the conflating effects of illumination. Here, we test the merits of this general supposition by confronting bumblebees (Bombus terrestris) with a color discrimination task that can be solved only if information about the illuminant is not discounted but maintained in processing and thus available to higher-order learned behavior. We show that bees correctly use the intensity and chromaticity of illumination as a contextual cue to guide them to different target colors. In fact, we trained bees to choose opposite, rather than most similar, target colors after an illumination change. This performance cannot be explained with a simple color-constancy mechanism that discounts illumination. Further tests show that bees do not use a simple assessment of the overhead illumination, but that they assess the spectral relationships between a floral target and its background. These results demonstrate that bees can be color-constant without discounting the illuminant; that, in fact, they can use information about the illuminant itself as a salient source of information.

  4. User-preferred color temperature adjustment for smartphone display under varying illuminants

    NASA Astrophysics Data System (ADS)

    Choi, Kyungah; Suk, Hyeon-Jeong

    2014-06-01

    The study aims to investigate the user-preferred color temperature adjustment for smartphone displays by observing the effect of the illuminant's chromaticity and intensity on the optimal white points preferred by users. For visual examination, subjects evaluated 14 display stimuli presented on the Samsung Galaxy S3 under 19 ambient illuminants. The display stimuli were composed of 14 nuanced whites varying in color temperature from 2900 to 18,900 K. The illuminant conditions varied with combinations of color temperature (2600 to 20,100 K) and illuminance level (30 to 3100 lx) that simulated daily lighting experiences. The subjects were asked to assess the optimal level of the display color temperatures based on their mental representation of the ideal white point. The study observed a positive correlation between the illuminant color temperatures and the optimal display color temperatures (r=0.89, p<0.05). However, the range of the color temperature of the smartphone display was much narrower than that of the illuminants. Based on the assessments by 100 subjects, a regression formula was derived to predict the adjustment of user-preferred color temperature under changing illuminant chromaticity. The formula is as follows: [Display Tcp=6534.75 log (Illuminant Tcp)-16304.68 (R=0.87, p<0.05)]. Moreover, supporting previous studies on color reproduction, the effect of illuminant chromaticity was relatively weaker under lower illuminance. The results of this experiment could be used as a theoretical basis for designers and manufacturers to adjust user-preferred color temperature for smartphone displays under various illuminant conditions.

  5. Physics and Chemistry in UV Illuminated Regions: the Horsehead Case

    NASA Astrophysics Data System (ADS)

    Guzman, Viviana V.; Pety, Jérôme; Gratier, Pierre; Goicoechea, Javier; Gerin, Maryvonne; Roueff, Evelyne

    2014-06-01

    Molecular lines are used to trace the structure of the interstellar medium and the physical conditions of the gas in different environments, from protoplanetary disks to high-z galaxies. To fully benefit from the diagnostic power of molecular lines, the formation and destruction paths of the molecules, including the interplay between gas-phase and grain surface chemistry, must be quantitatively understood. Well-defined sets of observations of simple template sources are key to benchmark the theoretical models. In this context the PDR of the Horsehead mane is a particularly interesting case because it has a simple geometry (almost 1D, viewed edge-on) and the density profile across the PDR is well constrained. In this talk, I will summarize our recent results on the ISM physics and chemistry in the Horsehead, from a complete and unbiased line survey at 1, 2 and 3mm performed with the IRAM-30m telescope, where approximately 30 species (plus their isotopologues) are detected with up to 7 atoms. I will show the importance of the interplay between the solid and gas phase chemistry in the formation of (complex) organic molecules, like H_2CO, CH_3OH, and CH_3CN, which reveal that photo-desorption of ices is an efficient mechanism to release molecules into the gas phase. The case of CH_3CN is especially surprising, as it is 40 times more abundant in the warm (Tkin˜60 K) UV-illuminated edge of the nebula, than in the shielded and colder (Tkin˜20 K) inner layers. I will show that complex molecules, such as HCOOH, CH_2CO, CH_3CHO, and CH_3CCH are easily detected in the PDR. I will also discuss new diagnostics of the UV-illuminated gas, like CF^+ (for which we recently resolved its hyperfine structure for the first time), which is observable from the ground, and we propose it can be used as a proxy of C^+. I will finish by reporting the first detection of a new molecule, recently confirmed to be the small hydrocarbon C_3H^+, which shows that photo-erosion of PAHs is needed to

  6. Fast Neuronal Imaging using Objective Coupled Planar Illumination Microscopy

    NASA Astrophysics Data System (ADS)

    Tarantino, Walter

    Complex computations performed by the brain are produced by activities of neuronal populations. There is a large diversity in the functions of each individual neuron, and neuronal activities occur in the time scale of milliseconds. In order to gain a fundamental understanding of the neuronal populations, one has to measure activity of each neuron at high temporal resolution, while investigating enough neurons to encapsulate the neuronal diversity. Traditional neurotechniques such as electrophysiology and optical imaging are constrained by the number of neurons whose activities can be simultaneously measured or the speed of measuring such activities. We have developed a novel light-sheet based technique called Objective Coupled Planar Illumination (OCPI) microscopy which is capable of measuring simultaneous activities of thousands of neurons at high speeds. In this thesis I pursue the following two aims: · Improve OCPI microscopy by enhancing the spatial resolution deeper in tissue. Tissue inhomogeneity and refractive index mismatch at the surface of the tissue lead to optical aberrations. We have compensated for such aberrations by (1) miniaturizing the OCPI illumination optics, so as to enable more vertical imaging of the tissue, (2) correcting for the angular defocus caused by the refraction at the immersion fluid/tissue interface, and (3) applying adaptive optics to correct for higher order optical aberrations. The improvement in the depth at which one can image tissue will enable the measurement of activities of neuronal populations in cortical areas. · Measure the diversity in the expression pattern of VSNs responsive to sulfated steroids. Nodari et al. have identified sulfated steroids as a novel family of ligands which activate vomeronasal sensory neurons (VSNs). Due to the experimental constraints, it has not been possible to obtain a comprehensive understanding of the number, location and functional characteristics of the sulfated steroid responsive VSNs

  7. Analysing intracellular deformation of polymer capsules using structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Cui, Jiwei; Sun, Huanli; Müllner, Markus; Yan, Yan; Noi, Ka Fung; Ping, Yuan; Caruso, Frank

    2016-06-01

    Understanding the behaviour of therapeutic carriers is important in elucidating their mechanism of action and how they are processed inside cells. Herein we examine the intracellular deformation of layer-by-layer assembled polymer capsules using super-resolution structured illumination microscopy (SIM). Spherical- and cylindrical-shaped capsules were studied in three different cell lines, namely HeLa (human epithelial cell line), RAW264.7 (mouse macrophage cell line) and differentiated THP-1 (human monocyte-derived macrophage cell line). We observed that the deformation of capsules was dependent on cell line, but independent of capsule shape. This suggests that the mechanical forces, which induce capsule deformation during cell uptake, vary between cell lines, indicating that the capsules are exposed to higher mechanical forces in HeLa cells, followed by RAW264.7 and then differentiated THP-1 cells. Our study demonstrates the use of super-resolution SIM in analysing intracellular capsule deformation, offering important insights into the cellular processing of drug carriers in cells and providing fundamental knowledge of intracellular mechanobiology. Furthermore, this study may aid in the design of novel drug carriers that are sensitive to deformation for enhanced drug release properties.Understanding the behaviour of therapeutic carriers is important in elucidating their mechanism of action and how they are processed inside cells. Herein we examine the intracellular deformation of layer-by-layer assembled polymer capsules using super-resolution structured illumination microscopy (SIM). Spherical- and cylindrical-shaped capsules were studied in three different cell lines, namely HeLa (human epithelial cell line), RAW264.7 (mouse macrophage cell line) and differentiated THP-1 (human monocyte-derived macrophage cell line). We observed that the deformation of capsules was dependent on cell line, but independent of capsule shape. This suggests that the mechanical forces

  8. Surface passivation of backside-illuminated InSb FPAs

    NASA Astrophysics Data System (ADS)

    Wei, Peng; Zheng, Kelin; Wang, Liwen; Geng, Dongfeng; Su, Xianjun

    2016-10-01

    A method of passivation of etch-thinned bulk InSb by anodic oxide grown by wet anodization and vacuum deposition of SiNx layers have been investigated Thinned bulk n-type InSb with (111) orientation forms distinctively two types of interfaces on the indium and antimony faces, respectively. The junctions are diffused on the indium face. The paper presents the process and characterization for surface passivation of the backside illuminated Sb face that absorbs the photons. The surface passivation and the interfaces are characterized with Metal-Insulator-Semiconductor (MIS) devices. The effect of anodic oxide/SiNx passivation was compared to SiNx passivation. The electrical features observed in the C-V curves of MIS structures indicate that anodic oxide grown by wet anodization has the better effect on reducing the surface states and surface recombination velocity. The low-frequency-like response in the inversion region of the C-V curves was explained in view of the oxidation states of In and Sb. Finally, by growing the 30nm anodic oxide and depositing 400nm SiNx on diode structure of InSb, the performance of FPA in this case was compared with the SiNx only method. The results showed the performance of device is better than for the SiNx only method.

  9. Illuminating structural proteins in viral "dark matter" with metaproteomics.

    PubMed

    Brum, Jennifer R; Ignacio-Espinoza, J Cesar; Kim, Eun-Hae; Trubl, Gareth; Jones, Robert M; Roux, Simon; VerBerkmoes, Nathan C; Rich, Virginia I; Sullivan, Matthew B

    2016-03-01

    Viruses are ecologically important, yet environmental virology is limited by dominance of unannotated genomic sequences representing taxonomic and functional "viral dark matter." Although recent analytical advances are rapidly improving taxonomic annotations, identifying functional dark matter remains problematic. Here, we apply paired metaproteomics and dsDNA-targeted metagenomics to identify 1,875 virion-associated proteins from the ocean. Over one-half of these proteins were newly functionally annotated and represent abundant and widespread viral metagenome-derived protein clusters (PCs). One primarily unannotated PC dominated the dataset, but structural modeling and genomic context identified this PC as a previously unidentified capsid protein from multiple uncultivated tailed virus families. Furthermore, four of the five most abundant PCs in the metaproteome represent capsid proteins containing the HK97-like protein fold previously found in many viruses that infect all three domains of life. The dominance of these proteins within our dataset, as well as their global distribution throughout the world's oceans and seas, supports prior hypotheses that this HK97-like protein fold is the most abundant biological structure on Earth. Together, these culture-independent analyses improve virion-associated protein annotations, facilitate the investigation of proteins within natural viral communities, and offer a high-throughput means of illuminating functional viral dark matter.

  10. Picosecond optical vortex pulse illumination forms a monocrystalline silicon needle

    PubMed Central

    Takahashi, Fuyuto; Miyamoto, Katsuhiko; Hidai, Hirofumi; Yamane, Keisaku; Morita, Ryuji; Omatsu, Takashige

    2016-01-01

    The formation of a monocrystalline silicon needle by picosecond optical vortex pulse illumination was demonstrated for the first time in this study. The dynamics of this silicon needle formation was further revealed by employing an ultrahigh-speed camera. The melted silicon was collected through picosecond pulse deposition to the dark core of the optical vortex, forming the silicon needle on a submicrosecond time scale. The needle was composed of monocrystalline silicon with the same lattice index (100) as that of the silicon substrate, and had a height of approximately 14 μm and a thickness of approximately 3 μm. Overlaid vortex pulses allowed the needle to be shaped with a height of approximately 40 μm without any changes to the crystalline properties. Such a monocrystalline silicon needle can be applied to devices in many fields, such as core–shell structures for silicon photonics and photovoltaic devices as well as nano- or microelectromechanical systems. PMID:26907639

  11. Diffusive-light invisibility cloak for transient illumination

    NASA Astrophysics Data System (ADS)

    Orazbayev, B.; Beruete, M.; Martínez, A.; García-Meca, C.

    2016-12-01

    Invisibility in a diffusive-light-scattering medium has been recently demonstrated by employing a scattering-cancellation core-shell cloak. Unlike nondiffusive cloaks, such a device can be simultaneously macroscopic, broadband, passive, polarization independent, and omnidirectional. Unfortunately, it has been verified that this cloak, as well as more sophisticated ones based on transformation optics, fail under pulsed illumination, invalidating their use for a variety of applications. Here, we introduce a different approach based on unimodular transformations that enables the construction of unidirectional diffusive-light cloaks exhibiting a perfect invisibility effect, even under transient conditions. Moreover, we demonstrate that a polygonal cloak can extend this functionality to multiple directions with a nearly ideal behavior, while preserving all other features. We propose and numerically verify a simple cloak realization based on a layered stack of two isotropic materials. The studied devices have several applications not addressable by any of the other cloaks proposed to date, including shielding from pulse-based detection techniques, cloaking undesired scattering elements in time-of-flight imaging or high-speed communication systems for diffusive environments, and building extreme optical security features. The discussed cloaking strategy could also be applied to simplify the implementation of thermal cloaks.

  12. Six-color solid state illuminator for cinema projector

    NASA Astrophysics Data System (ADS)

    Huang, Junejei; Wang, Yuchang

    2014-09-01

    Light source for cinema projector requires reliability, high brightness, good color and 3D for without silver screens. To meet these requirements, a laser-phosphor based solid state illuminator with 6 primary colors is proposed. The six primary colors are divided into two groups and include colors of R1, R2, G1, G2, B1 and B2. Colors of B1, B2 and R2 come from lasers of wavelengths 440 nm, 465 nm and 639 nm. Color of G1 comes from G-phosphor pumped by B2 laser. Colors of G2 and R1 come from Y-phosphor pumped by B1 laser. Two groups of colors are combined by a multiband filter and working by alternately switching B1 and B2 lasers. The combined two sequences of three colors are sent to the 3-chip cinema projector and synchronized with frame rate of 120Hz. In 2D mode, the resulting 6 primary colors provide a very wide color gamut. In 3D mode, two groups of red, green and blue primary colors provide two groups of images that received by left and right eyes.

  13. Detection of Fish Bones in Cod Fillets by UV Illumination.

    PubMed

    Wang, Sheng; Nian, Rui; Cao, Limin; Sui, Jianxin; Lin, Hong

    2015-07-01

    The presence of fish bones is now regarded as an important hazard in fishery products, and there is increasing demand for new analytical techniques to control it more effectively. Here, the fluorescent properties of cod bones under UV illumination were investigated, and the maximal wavelengths for excitation and emission were determined to be 320 nm and 515 nm, respectively, demonstrating significantly different fluorescence characteristics and much higher fluorescence intensity compared to those of fillet muscles. Based on the results, UV fluorescence-assisted candling for the detection of bones in fishery products was developed for the first time. Using cod fillets as samples, the detection ratio of this technique was calculated as 90.86%, significantly higher than that of traditional candling under daylight (76.78%). Moreover, the working efficiency of the new technique was about 26% higher than that of the traditional method. A UV fluorescence imaging framework was also developed, and a method for automatic identification of the fish bones in the cod fillets based on the linear discriminant analysis proposed by Fisher was preliminarily realized, but the detection ratio was demonstrated to be relatively poor compared to those of candling techniques. These results allow us to suggest UV-based methods as new and promising approaches for routine monitoring of bones in fishery products.

  14. Simulating the effect of illumination using color transformations

    NASA Astrophysics Data System (ADS)

    Gupta, Maya R.; Upton, Stephen; Bowen, Jayson

    2005-03-01

    We investigate design and estimation issues for using the standard color management profile architecture for general custom image enhancement. Color management profiles are a flexible architecture for describing a mapping from an original colorspace to a new colorspace. We investigate use of this same architecture for describing color enhancements that could be defined by a non-technical user using samples of the mapping, just as color management is based on samples of a mapping between an original colorspace and a new colorspace. As an example enhancement, we work with photos of the 24 color patch Macbeth chart under different illuminations, with the goal of defining transformations that would take, for example, a studio D65 image and reproduce it as though it had been taken during a particular sunset. The color management profile architecture includes a look-up-table and interpolation. We concentrate on the estimation of the look-up-table points from minimal number of color enhancement samples (comparing interpolative and extrapolative statistical learning techniques), and evaluate the feasibility of using the color management architecture for custom enhancement definitions.

  15. Imaging of gaseous oxygen through DFB laser illumination

    NASA Astrophysics Data System (ADS)

    Cocola, L.; Fedel, M.; Tondello, G.; Poletto, L.

    2016-05-01

    A Tunable Diode Laser Absorption Spectroscopy setup with Wavelength Modulation has been used together with a synchronous sampling imaging sensor to obtain two-dimensional transmission-mode images of oxygen content. Modulated laser light from a 760nm DFB source has been used to illuminate a scene from the back while image frames were acquired with a high dynamic range camera. Thanks to synchronous timing between the imaging device and laser light modulation, the traditional lock-in approach used in Wavelength Modulation Spectroscopy was replaced by image processing techniques, and many scanning periods were averaged together to allow resolution of small intensity variation over the already weak absorption signals from oxygen absorption band. After proper binning and filtering, the time-domain waveform obtained from each pixel in a set of frames representing the wavelength scan was used as the single detector signal in a traditional TDLAS-WMS setup, and so processed through a software defined digital lock-in demodulation and a second harmonic signal fitting routine. In this way the WMS artifacts of a gas absorption feature were obtained from each pixel together with intensity normalization parameter, allowing a reconstruction of oxygen distribution in a two-dimensional scene regardless from broadband transmitted intensity. As a first demonstration of the effectiveness of this setup, oxygen absorption images of similar containers filled with either oxygen or nitrogen were acquired and processed.

  16. Active focus stabilization for upright selective plane illumination microscopy

    PubMed Central

    Hedde, Per Niklas; Gratton, Enrico

    2015-01-01

    Due to its sectioning capability, large field of view, and minimal light exposure, selective plane illumination microscopy has become the preferred choice for 3D time lapse imaging. Single cells in a dish can be conveniently imaged using an upright/inverted configuration. However, for measurements on long time scales (hours to days), mechanical drift is a problem; especially for studies of mammalian cells that typically require heating to 37°C which causes a thermal gradient across the instrument. Since the light sheet diverges towards the edges of the field of view, such a drift leads to a decrease in axial resolution over time. Or, even worse, the specimen could move out of the imaging volume. Here, we present a simple, cost-effective way to stabilize the axial position using the microscope camera to track the sample position. Thereby, sample loss is prevented and an optimal axial resolution is maintained by keeping the sample at the position where the light sheet is at its thinnest. We demonstrate the virtue of our approach by measurements of the light sheet thickness and 3D time lapse imaging of a cell monolayer at physiological conditions. PMID:26072829

  17. Sub-nanometer glass surface dynamics induced by illumination

    SciTech Connect

    Nguyen, Duc; Nienhaus, Lea; Haasch, Richard T.; Lyding, Joseph; Gruebele, Martin

    2015-06-21

    Illumination is known to induce stress and morphology changes in opaque glasses. Amorphous silicon carbide (a-SiC) has a smaller bandgap than the crystal. Thus, we were able to excite with 532 nm light a 1 μm amorphous surface layer on a SiC crystal while recording time-lapse movies of glass surface dynamics by scanning tunneling microscopy (STM). Photoexcitation of the a-SiC surface layer through the transparent crystal avoids heating the STM tip. Up to 6 × 10{sup 4} s, long movies of surface dynamics with 40 s time resolution and sub-nanometer spatial resolution were obtained. Clusters of ca. 3-5 glass forming units diameter are seen to cooperatively hop between two states at the surface. Photoexcitation with green laser light recruits immobile clusters to hop, rather than increasing the rate at which already mobile clusters hop. No significant laser heating was observed. Thus, we favor an athermal mechanism whereby electronic excitation of a-SiC directly controls glassy surface dynamics. This mechanism is supported by an exciton migration-relaxation-thermal diffusion model. Individual clusters take ∼1 h to populate states differently after the light intensity has changed. We believe the surrounding matrix rearranges slowly when it is stressed by a change in laser intensity, and clusters serve as a diagnostic. Such cluster hopping and matrix rearrangement could underlie the microscopic mechanism of photoinduced aging of opaque glasses.

  18. Novel cylindrical illuminator tip for ultraviolet light delivery

    NASA Astrophysics Data System (ADS)

    Shangguan, HanQun; Haw, Thomas E.; Gregory, Kenton W.; Casperson, Lee W.

    1993-06-01

    The design, processing, and sequential testing of a novel cylindrical diffusing optical fiber tip for ultraviolet light delivery is described. This device has been shown to uniformly (+/- 15%) illuminate angioplasty balloons, 20 mm in length, that are used in an experimental photochemotherapeutic treatment of swine intimal hyperplasia. Our experiments show that uniform diffusing tips of < 400 micron diameter can be reliably constructed for this and other interstitial applications. Modeling results indicate that this design is scalable to smaller diameters. The diffusing tips are made by stripping the protective buffer and etching away the cladding over a length of 20 mm from the fiber tip and replacing it with a thin layer of optical epoxy mixed with Al2O3 powder. To improve the uniformity and ease of fabrication, we have evaluated a new device configuration where the tip is etched into a modified conical shape, and the distal end face is polished and then coated with an optically opaque epoxy. This is shown to uniformly scatter approximately 70% of the light launched into the fiber without forward transmission.

  19. Full-color structured illumination optical sectioning microscopy

    PubMed Central

    Qian, Jia; Lei, Ming; Dan, Dan; Yao, Baoli; Zhou, Xing; Yang, Yanlong; Yan, Shaohui; Min, Junwei; Yu, Xianghua

    2015-01-01

    In merits of super-resolved resolution and fast speed of three-dimensional (3D) optical sectioning capability, structured illumination microscopy (SIM) has found variety of applications in biomedical imaging. So far, most SIM systems use monochrome CCD or CMOS cameras to acquire images and discard the natural color information of the specimens. Although multicolor integration scheme are employed, multiple excitation sources and detectors are required and the spectral information is limited to a few of wavelengths. Here, we report a new method for full-color SIM with a color digital camera. A data processing algorithm based on HSV (Hue, Saturation, and Value) color space is proposed, in which the recorded color raw images are processed in the Hue, Saturation, Value color channels, and then reconstructed to a 3D image with full color. We demonstrated some 3D optical sectioning results on samples such as mixed pollen grains, insects, micro-chips and the surface of coins. The presented technique is applicable to some circumstance where color information plays crucial roles, such as in materials science and surface morphology. PMID:26415516

  20. Advancing ovarian folliculometry with selective plane illumination microscopy

    PubMed Central

    Lin, Hsiao-Chun Amy; Dutta, Rahul; Mandal, Subhamoy; Kind, Alexander; Schnieke, Angelika; Razansky, Daniel

    2016-01-01

    Determination of ovarian status and follicle monitoring are common methods of diagnosing female infertility. We evaluated the suitability of selective plane illumination microscopy (SPIM) for the study of ovarian follicles. The large field of view and fast acquisition speed of our SPIM system enables rendering of volumetric image stacks from intact whole porcine ovarian follicles, clearly visualizing follicular features including follicle volume and average diameter (70 μm–2.5 mm), their spherical asymmetry parameters, size of developing cumulus oophorus complexes (40 μm–110 μm), and follicular wall thickness (90 μm–120 μm). Follicles at all developmental stages were identified. A distribution of the theca thickness was measured for each follicle, and a relationship between these distributions and the stages of follicular development was discerned. The ability of the system to non-destructively generate sub-cellular resolution 3D images of developing follicles, with excellent image contrast and high throughput capacity compared to conventional histology, suggests that it can be used to monitor follicular development and identify structural abnormalities indicative of ovarian ailments. Accurate folliculometric measurements provided by SPIM images can immensely help the understanding of ovarian physiology and provide important information for the proper management of ovarian diseases. PMID:27905503

  1. Making light work: illuminating the future of biomedical optics.

    PubMed

    Elwell, Clare E; Cooper, Chris E

    2011-11-28

    In 1996, the Royal Society held a Discussion Meeting entitled 'Near-infrared spectroscopy and imaging of living systems'. In 2010, this topic was revisited in a Theo Murphy Royal Society Scientific Discussion Meeting entitled 'Making light work: illuminating the future of biomedical optics'. The second meeting provided the opportunity for leading researchers to reflect on how the technology, methods and applications have evolved over the past 14 years and assess where they have made a major impact. Particular emphasis was placed on discussions of future prospects and associated challenges. This Introduction provides an overview of the state of the art of near-infrared spectroscopy (NIRS) and biomedical optics, with specific reference to the contributed papers from the invited speakers included in this issue. Importantly, we also reflect on the contributions from all of the attendees by highlighting the issues raised during oral presentations, facilitated panel sessions and discussions, and use these to summarize the current opinion on the development and application of optical systems for use in the clinical and life sciences. A notable outcome from the meeting was a plan to establish a biennial international conference for developers and users of NIRS technologies.

  2. EO/IR/Laser illumination sensors for perimeter security

    NASA Astrophysics Data System (ADS)

    Natelson, David

    2007-04-01

    The integration of varied types of EO, IR, and Laser Illumination sensors used for perimeter security greatly improves the data that is available to the process of classifying potential threats. A key component of the design of layered sets of sensors is to understand the method in which detection, recognition, and identification distances are defined by each vendor. Historically, it has been challenging to compare each vendor's stated values as each type of sensor has unique characteristics that hinder the process of performing a so called "apples to apples" comparison. This results in more costly field testing and software simulations that attempt to model real world deployments. What we do know is that solutions are desired where multiple sensors are used to provide information to the Detection, Recognition through Identification process, as well as, associated human or software-based threat assessment and reaction processes. Perimeter security typically involves several layers of detection and investigation. Many entities have invested in detection sensors only to find out that they lack integrated or queued investigative sensors that provide a better return on investment for their systems. When you add night vision sensors to the mix, the challenges increase. This paper will examine sensor technologies and integration/command control/analytics technologies that are attempting to tie things together. The latest technologies including queued sensors and advances in detection/analytics using PTZ sensors will be covered.

  3. Advancing ovarian folliculometry with selective plane illumination microscopy

    NASA Astrophysics Data System (ADS)

    Lin, Hsiao-Chun Amy; Dutta, Rahul; Mandal, Subhamoy; Kind, Alexander; Schnieke, Angelika; Razansky, Daniel

    2016-12-01

    Determination of ovarian status and follicle monitoring are common methods of diagnosing female infertility. We evaluated the suitability of selective plane illumination microscopy (SPIM) for the study of ovarian follicles. The large field of view and fast acquisition speed of our SPIM system enables rendering of volumetric image stacks from intact whole porcine ovarian follicles, clearly visualizing follicular features including follicle volume and average diameter (70 μm–2.5 mm), their spherical asymmetry parameters, size of developing cumulus oophorus complexes (40 μm–110 μm), and follicular wall thickness (90 μm–120 μm). Follicles at all developmental stages were identified. A distribution of the theca thickness was measured for each follicle, and a relationship between these distributions and the stages of follicular development was discerned. The ability of the system to non-destructively generate sub-cellular resolution 3D images of developing follicles, with excellent image contrast and high throughput capacity compared to conventional histology, suggests that it can be used to monitor follicular development and identify structural abnormalities indicative of ovarian ailments. Accurate folliculometric measurements provided by SPIM images can immensely help the understanding of ovarian physiology and provide important information for the proper management of ovarian diseases.

  4. Illuminating the relationship between shared learning and the workplace.

    PubMed

    Kennard, Jerry

    2002-07-01

    This investigation represents an attempt to illuminate issues in the relationship between shared learning, aspects of organizational climate, teamwork practices and inter-personal contact between health professionals. The study, completed in 1998 and conducted over the previous 3 years, involved 57 post-qualified health professionals undertaking a part-time 'top-up' degree in health studies. The extent to which climate promoted, maintained or inhibited collaborative practices was considered by examining the views and experiences of course participants over three successive years. Most interest in collaborative practice came from individuals already actively engaged in multidisciplinary work and with a clear sense of role within that context. No evidence was found to associate this form of shared learning with new or enhanced collaborative activity, but nearly all the professions involved accepted the principle of more flexible forms of working. Poor perceptions between disciplines were associated with low levels of contact in the workplace. Students who undertook a module focusing on collaborative practice had more positive perceptions about their work and were less likely to emphasize work demands in terms of shift-patterns, fatigue and/or stress.

  5. Broadband illumination of superconducting pair breaking photon detectors

    NASA Astrophysics Data System (ADS)

    Guruswamy, T.; Goldie, D. J.; Withington, S.

    2016-04-01

    Understanding the detailed behaviour of superconducting pair breaking photon detectors such as Kinetic Inductance Detectors (KIDs) requires knowledge of the nonequilibrium quasiparticle energy distributions. We have previously calculated the steady state distributions resulting from uniform absorption of monochromatic sub gap and above gap frequency radiation by thin films. In this work, we use the same methods to calculate the effect of illumination by broadband sources, such as thermal radiation from astrophysical phenomena or from the readout system. Absorption of photons at multiple above gap frequencies is shown to leave unchanged the structure of the quasiparticle energy distribution close to the superconducting gap. Hence for typical absorbed powers, we find the effects of absorption of broadband pair breaking radiation can simply be considered as the sum of the effects of absorption of many monochromatic sources. Distribution averaged quantities, like quasiparticle generation efficiency η, match exactly a weighted average over the bandwidth of the source of calculations assuming a monochromatic source. For sub gap frequencies, however, distributing the absorbed power across multiple frequencies does change the low energy quasiparticle distribution. For moderate and high absorbed powers, this results in a significantly larger η-a higher number of excess quasiparticles for a broadband source compared to a monochromatic source of equal total absorbed power. Typically in KIDs the microwave power absorbed has a very narrow bandwidth, but in devices with broad resonance characteristics (low quality factors), this increase in η may be measurable.

  6. Full-color structured illumination optical sectioning microscopy

    NASA Astrophysics Data System (ADS)

    Qian, Jia; Lei, Ming; Dan, Dan; Yao, Baoli; Zhou, Xing; Yang, Yanlong; Yan, Shaohui; Min, Junwei; Yu, Xianghua

    2015-09-01

    In merits of super-resolved resolution and fast speed of three-dimensional (3D) optical sectioning capability, structured illumination microscopy (SIM) has found variety of applications in biomedical imaging. So far, most SIM systems use monochrome CCD or CMOS cameras to acquire images and discard the natural color information of the specimens. Although multicolor integration scheme are employed, multiple excitation sources and detectors are required and the spectral information is limited to a few of wavelengths. Here, we report a new method for full-color SIM with a color digital camera. A data processing algorithm based on HSV (Hue, Saturation, and Value) color space is proposed, in which the recorded color raw images are processed in the Hue, Saturation, Value color channels, and then reconstructed to a 3D image with full color. We demonstrated some 3D optical sectioning results on samples such as mixed pollen grains, insects, micro-chips and the surface of coins. The presented technique is applicable to some circumstance where color information plays crucial roles, such as in materials science and surface morphology.

  7. Quantitative 3D structured illumination microscopy of nuclear structures.

    PubMed

    Kraus, Felix; Miron, Ezequiel; Demmerle, Justin; Chitiashvili, Tsotne; Budco, Alexei; Alle, Quentin; Matsuda, Atsushi; Leonhardt, Heinrich; Schermelleh, Lothar; Markaki, Yolanda

    2017-05-01

    3D structured illumination microscopy (3D-SIM) is the super-resolution technique of choice for multicolor volumetric imaging. Here we provide a validated sample preparation protocol for labeling nuclei of cultured mammalian cells, image acquisition and registration practices, and downstream image analysis of nuclear structures and epigenetic marks. Using immunostaining and replication labeling combined with image segmentation, centroid mapping and nearest-neighbor analyses in open-source environments, 3D maps of nuclear structures are analyzed in individual cells and normalized to fluorescence standards on the nanometer scale. This protocol fills an unmet need for the application of 3D-SIM to the technically challenging nuclear environment, and subsequent quantitative analysis of 3D nuclear structures and epigenetic modifications. In addition, it establishes practical guidelines and open-source solutions using ImageJ/Fiji and the TANGO plugin for high-quality and routinely comparable data generation in immunostaining experiments that apply across model systems. From sample preparation through image analysis, the protocol can be executed within one week.

  8. Error correcting coding-theory for structured light illumination systems

    NASA Astrophysics Data System (ADS)

    Porras-Aguilar, Rosario; Falaggis, Konstantinos; Ramos-Garcia, Ruben

    2017-06-01

    Intensity discrete structured light illumination systems project a series of projection patterns for the estimation of the absolute fringe order using only the temporal grey-level sequence at each pixel. This work proposes the use of error-correcting codes for pixel-wise correction of measurement errors. The use of an error correcting code is advantageous in many ways: it allows reducing the effect of random intensity noise, it corrects outliners near the border of the fringe commonly present when using intensity discrete patterns, and it provides a robustness in case of severe measurement errors (even for burst errors where whole frames are lost). The latter aspect is particular interesting in environments with varying ambient light as well as in critical safety applications as e.g. monitoring of deformations of components in nuclear power plants, where a high reliability is ensured even in case of short measurement disruptions. A special form of burst errors is the so-called salt and pepper noise, which can largely be removed with error correcting codes using only the information of a given pixel. The performance of this technique is evaluated using both simulations and experiments.

  9. Detecting small surface vibrations by passive electro-optical illumination

    NASA Astrophysics Data System (ADS)

    Buoni, Matthew; Pereira, Wellesley; Weber, Reed A.; Garcia-Cervera, Carlos

    2014-09-01

    We have performed research to understand the feasibility of using signals received by EOIR sensors to detect small vibrations in surfaces illuminated by sunlight. The vibration models consider buildings with vibrating roofs, as well as ground vibrations due to buried structures. For the surface buildings, we investigated two approaches. One involved treating the roof as an elastic medium subject to deformation resulting in a PDE whose solution describes the fluctuation in the surface's normal direction vector. The second approach treated the roof as a rigid mass subject to motion in six degrees of freedom, while modeling the dynamics of the building's frame, and tuning the parameters to result in resonant frequencies similar to real buildings (~3-7 Hz). We applied the appropriate physical models of reflected and scattered light to various surfaces, specular (insulator or conductor), rough but still reflective, or diffusely scattering (Lambertian). Matlab code was developed to perform numerical simulations of any system configuration described above and easily add new models. The main engine of the code is a signal calculator and analyzer that sums the total intensity of received light over a "scene" with a variety of surface materials, orientations, polarization (if any), and other parameters. A resulting signal versus time is generated that may be analyzed in order to: 1) optimize sensitivity, or 2) detect the vibration signature of a structure of interest. The results of this study will enable scientists/engineers to optimize signal detection, possibly from space, for passive exploitation of scattered light modulated by vibrating surfaces.

  10. MEMS compatible illumination and imaging micro-optical systems

    NASA Astrophysics Data System (ADS)

    Bräuer, A.; Dannberg, P.; Duparré, J.; Höfer, B.; Schreiber, P.; Scholles, M.

    2007-01-01

    The development of new MOEMS demands for cooperation between researchers in micromechanics, optoelectronics and microoptics at a very early state. Additionally, microoptical technologies being compatible with structured silicon have to be developed. The microoptical technologies used for two silicon based microsystems are described in the paper. First, a very small scanning laser projector with a volume of less than 2 cm 3, which operates with a directly modulated lasers collimated with a microlens, is shown. The laser radiation illuminates a 2D-MEMS scanning mirror. The optical design is optimized for high resolution (VGA). Thermomechanical stability is realized by design and using a structured ceramics motherboard. Secondly, an ultrathin CMOS-camera having an insect inspired imaging system has been realized. It is the first experimental realization of an artificial compound eye. Micro-optical design principles and technology is used. The overall thickness of the imaging system is only 320 μm, the diagonal field of view is 21°, and the f-number is 2.6. The monolithic device consists of an UV-replicated microlens array upon a thin silica substrate with a pinhole array in a metal layer on the back side. The pitch of the pinholes differs from that of the lens array to provide individual viewing angle for each channel. The imaging chip is directly glued to a CMOS sensor with adapted pitch. The whole camera is less than 1mm thick. New packaging methods for these systems are under development.

  11. Incremental theory of diffraction for complex point source illumination

    NASA Astrophysics Data System (ADS)

    Polemi, A.; Carluccio, G.; Albani, M.; Toccafondi, A.; Maci, S.

    2007-12-01

    The complex point source (CPS) is a solution of the Helmholtz equation obtained by analytical continuation of the free-space Green's function for complex position of the point source. The CPS representation of radiated fields can be used within a ray code to predict the interaction between an antenna and its actual environment, when standard diffraction formulations are extended to the CPS illumination. In the past, ray-based diffraction theories such as the geometrical theory of diffraction and its uniform version (UTD) were extended to complex point source fields, leaving, however, open some problematic issues concerning the "complex ray tracing". In this paper, the generalization of the incremental theory of diffraction (ITD) to CPS is formulated. The total field scattered by the object is given in terms of line integration along edge discontinuities of ITD diffraction coefficients plus the discontinuous geometrical optics (GO). An incremental form of the discontinuous GO is also proposed to overcome GO "complex ray tracing" difficulties. The final formulation is very simple and leads to accurate results that are successfully validated by comparison against a method of moment solution.

  12. Edge-on illumination photon-counting for medical imaging

    NASA Astrophysics Data System (ADS)

    Doni, M.; Visser, J.; Koffeman, E.; Herrmann, C.

    2015-08-01

    In medical X-ray Computed Tomography (CT) a silicon based sensor (300-1000 μm) in face-on configuration does not collect the incoming X-rays effectively because of their high energy (40-140 keV). For example, only 2% of the incoming photons at 100 keV are stopped by a 500 μm thick silicon layer. To increase the efficiency, one possibility is to use materials with higher Z (e.g. GaAs, CZT), which have some drawbacks compared to silicon, such as short carrier lifetime or low mobility. Therefore, we investigate whether illuminating silicon edge-on instead of face-on is a solution. Aim of the project is to find and take advantage of the benefits of this new geometry when used for a pixel detector. In particular, we employ a silicon hybrid pixel detector, which is read out by a chip from the Medipix family. Its capabilities to be energy selective will be a notable advantage in energy resolved (spectral) X-ray CT.

  13. National education program for energy efficient illumination engineering

    NASA Astrophysics Data System (ADS)

    Walker, Constance E.; Pompea, Stephen M.

    2011-05-01

    About one-third of outdoor lighting escapes unused into the sky, wasting energy and causing sky glow. Because of excessive sky glow around astronomical facilities, the National Optical Astronomy Observatory has a strong motivation to lead light pollution education efforts. While our original motivation of preserving the dark skies near observatories is still important, energy conservation is a critical problem that needs to be addressed nationwide. To address this problem we have created an extensive educational program on understanding and measuring light pollution. A set of four learning experiences introduces school students at all grade levels to basic energy-responsive illumination engineering design principles that can minimize light pollution. We created and utilize the GLOBE at Night citizen science light pollution assessment campaign as a cornerstone activity. We also utilize educational activities on light shielding that are introduced through a teaching kit. These two components provide vocabulary, concepts, and visual illustrations of the causes of light pollution. The third, more advanced component is the school outdoor lighting audit, which has students perform an audit and produce a revised master plan for compliant lighting. These learning experiences provide an integrated learning unit that is highly adaptable for U.S. and international education efforts in this area.

  14. Demonstration of Recessed Downlight Technologies: Power and Illumination Assessment

    SciTech Connect

    Parker, Steven A.; Beeson, Tracy A.

    2009-11-20

    Solid state lighting (SSL), specifically light-emitting diodes (LED), has been advancing at a rapid pace, and there are presently multiple products available that serve as direct replacements for traditional luminaires. In this demonstration, conventional recessed lights in a conference room were used to compare conventional incandescent A-lamps, incandescent reflector R-lamps, dimming compact fluorescent lamps (CFL), to an LED replacement product. The primary focus during the study was on light delivered to the task plane as provided by the power required by the lighting system. Vertical illuminance, dimming range, and color shift are also important indicators of lighting quality and are discussed in the report. The results clearly showed that LEDs, with dimming-capable drivers, are much more efficient than incandescent and CFLs. Further, LEDs provide much smoother and consistent dimming than dimmable CFLs. On the potential negative side, it is important that the dimming switch be identified as compatible with the LED driver. A wide variety of dimmer switches are capable of dimming LEDs down to 15% of full light output, while select others can be capable of dimming LEDs down to 5%. In addition, LEDs can be intensive light sources, which can result in uncomfortable glare in some applications and to some occupants. Higher ceiling (9-foot or greater) or non-specular reflectors can act to alleviate the potential for glare.

  15. On the identification of folium and orchil on illuminated manuscripts

    NASA Astrophysics Data System (ADS)

    Aceto, Maurizio; Calà, Elisa; Agostino, Angelo; Fenoglio, Gaia; Idone, Ambra; Porter, Cheryl; Gulmini, Monica

    2017-01-01

    The identification of the two purple dyes folium and orchil has rarely been reported in the analysis of painted artworks, especially when analysing illuminated manuscripts. This is not consistent with the fact that ancient literary sources suggested their use as substitutes for the more expensive Tyrian purple dye. By employing non-invasive spectroscopic techniques, the present work demonstrates that these dyes were actually widely used in the production of ancient manuscripts. By employing UV-visible diffuse reflectance spectrophotometry with optic fibres (FORS) and spectrofluorimetry, the abundant identification of both dyes on medieval manuscripts was performed by comparing the spectra recorded on ancient codices with those obtained on accurate replicas of dyed or painted parchment. Moreover, examples are also reported whereby the considered purple dyes were used in mixtures with other colourants. The overall information obtained here allowed us to define new boundaries for the time range in which orchil and folium dyes were used which is wider than previously thought, and to focus on their particular uses in the decoration of books.

  16. Superresolution imaging with optical fluctuation using speckle patterns illumination

    PubMed Central

    Kim, MinKwan; Park, ChungHyun; Rodriguez, Christophe; Park, YongKeun; Cho, Yong-Hoon

    2015-01-01

    Superresolution fluorescence microscopy possesses an important role for the study of processes in biological cells with subdiffraction resolution. Recently, superresolution methods employing the emission properties of fluorophores have rapidly evolved due to their technical simplicity and direct applicability to existing microscopes. However, the application of these methods has been limited to samples labeled with fluorophores that can exhibit intrinsic emission properties at a restricted timescale, especially stochastic blinking. Here, we present a superresolution method that can be performed using general fluorophores, regardless of this intrinsic property. Utilizing speckle patterns illumination, temporal emission fluctuation of fluorophores is induced and controlled, from which a superresolution image can be obtained exploiting its statistical property. Using this method, we demonstrate, theoretically and experimentally, the capability to produce subdiffraction resolution images. A spatial resolution of 500 nm, 300 nm and 140 nm with 0.4, 0.5 and 1.4 NA objective lenses respectively was achieved in various samples with an enhancement factor of 1.6 compared to conventional fluorescence microscopy. PMID:26572283

  17. Active focus stabilization for upright selective plane illumination microscopy.

    PubMed

    Hedde, Per Niklas; Gratton, Enrico

    2015-06-01

    Due to its sectioning capability, large field of view, and minimal light exposure, selective plane illumination microscopy has become the preferred choice for 3D time lapse imaging. Single cells in a dish can be conveniently imaged using an upright/inverted configuration. However, for measurements on long time scales (hours to days), mechanical drift is a problem; especially for studies of mammalian cells that typically require heating to 37°C which causes a thermal gradient across the instrument. Since the light sheet diverges towards the edges of the field of view, such a drift leads to a decrease in axial resolution over time. Or, even worse, the specimen could move out of the imaging volume. Here, we present a simple, cost-effective way to stabilize the axial position using the microscope camera to track the sample position. Thereby, sample loss is prevented and an optimal axial resolution is maintained by keeping the sample at the position where the light sheet is at its thinnest. We demonstrate the virtue of our approach by measurements of the light sheet thickness and 3D time lapse imaging of a cell monolayer at physiological conditions.

  18. Transient proton inflows during illumination of anaerobic Halobacterium halobium cells

    NASA Technical Reports Server (NTRS)

    Helgerson, S. L.; Stoeckenius, W.

    1985-01-01

    The roles of bacteriorhodopsin (bR), halorhodopsin (hR), and the H(+)-ATPase in the proton uptake in intact cells are examined. The Halobacterium halobium strains and solutions utilized in the experiment, and the techniques for measuring extracellular pH changes and intracellular K(+) concentrations are described. It is observed that in Halobacterium halobium strain R1, containing bR and hR, the light-driven proton uptake is divided into three transient inflows superimposed on the larger proton outflow. Under anaerobic conditions early proton uptake consists of an inflow which can be blocked with Dio-9 and a second inflow that can be eliminated by low concentrations (less than 125 nm) of triphenyltin chloride (TPT). The effects of Dio-9 and TPT on the passive proton-hydroxyl permeability of the cell membrane are investigated. A third transient light-driven proton flow observed at later times of illumination is studied. The data reveal that the first proton inflow correlates with proton dependent ATP synthesis; the second inflow is a passive uptake through an unidentified channel in response to electrogenic chloride pumping by bR and/or hR; and the third inflow correlates with the Na(+)/H(+) antiporter function.

  19. Structured-illumination reflectance imaging for enhanced detection of subsurface tissue bruising in apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this research, a novel method of fresh bruise detection was developed using a structured illumination reflectance imaging (SIRI) system. The SIRI system projects sinusoidal patterns of illumination onto samples, and image demodulation is then used to recover depth-specific information through var...

  20. Image registration under illumination variations using region-based confidence weighted M-estimators.

    PubMed

    Fouad, Mohamed M; Dansereau, Richard M; Whitehead, Anthony D

    2012-03-01

    We present an image registration model for image sets with arbitrarily shaped local illumination variations between images. Any nongeometric variations tend to degrade the geometric registration precision and impact subsequent processing. Traditional image registration approaches do not typically account for changes and movement of light sources, which result in interimage illumination differences with arbitrary shape. In addition, these approaches typically use a least-square estimator that is sensitive to outliers, where interimage illumination variations are often large enough to act as outliers. In this paper, we propose an image registration approach that compensates for arbitrarily shaped interimage illumination variations, which are processed using robust M -estimators tuned to that region. Each M-estimator for each illumination region has a distinct cost function by which small and large interimage residuals are unevenly penalized. Since the segmentation of the interimage illumination variations may not be perfect, a segmentation confidence weighting is also imposed to reduce the negative effect of mis-segmentation around illumination region boundaries. The proposed approach is cast in an iterative coarse-to-fine framework, which allows a convergence rate similar to competing intensity-based image registration approaches. The overall proposed approach is presented in a general framework, but experimental results use the bisquare M-estimator with region segmentation confidence weighting. A nearly tenfold improvement in subpixel registration precision is seen with the proposed technique when convergence is attained, as compared with competing techniques using both simulated and real data sets with interimage illumination variations.

  1. Micro-optics: enabling technology for illumination shaping in optical lithography

    NASA Astrophysics Data System (ADS)

    Voelkel, Reinhard

    2014-03-01

    Optical lithography has been the engine that has empowered semiconductor industry to continually reduce the half-pitch for over 50 years. In early mask aligners a simple movie lamp was enough to illuminate the photomask. Illumination started to play a more decisive role when proximity mask aligners appeared in the mid-1970s. Off-axis illumination was introduced to reduce diffraction effects. For early projection lithography systems (wafer steppers), the only challenge was to collect the light efficiently to ensure short exposure time. When projection optics reached highest level of perfection, further improvement was achieved by optimizing illumination. Shaping the illumination light, also referred as pupil shaping, allows the optical path from reticle to wafer to be optimized and thus has a major impact on aberrations and diffraction effects. Highly-efficient micro-optical components are perfectly suited for this task. Micro-optics for illumination evolved from simple flat-top (fly's-eye) to annular, dipole, quadrupole, multipole and freeform illumination. Today, programmable micro-mirror arrays allow illumination to be changed on the fly. The impact of refractive, diffractive and reflective microoptics for photolithography will be discussed.

  2. 75 FR 28604 - The United Illuminating Company; Notice of Petition for Declaratory Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission The United Illuminating Company; Notice of Petition for Declaratory Order... Illuminating Company filed a Petition for Declaratory Order, requesting the Commission to issue an...

  3. Back-illuminated CCD imager adapted for contrast transfer function measurements thereon

    NASA Technical Reports Server (NTRS)

    Levine, Peter A. (Inventor)

    1987-01-01

    Stripe patterns of varying spatial frequency, formed in the top-metalization of a back-illuminated solid-state imager, facilitate on-line measurement of contrast transfer function during wafer-probe testing. The imager may be packaged to allow front-illumination during in-the-field testing after its manufacture.

  4. Image segmentation using common techniques and illumination applied to tissue culture

    NASA Astrophysics Data System (ADS)

    Vazquez Rueda, Martin G.; Hahn, Federico

    1998-03-01

    This paper present the comparation and performance on no adaptive image segmentation techniques using illumination and adaptive image segmentation techniques. Results obtained on indoor plant reproduction by tissue culture, show the improve in time process, simplify the image segmentation process, experimental results are presented using common techniques in image processing and illumination, contrasted with adaptive image segmentation.

  5. Using spherical aberrations of a singlet lens to get a uniform LED illumination

    NASA Astrophysics Data System (ADS)

    Gao, Guangjun; Li, Lin; Huang, Yifan

    2005-02-01

    In order to get a simple LED illumination system with a short length, the LED needs a large irradiant angle (2ω = 90°) and the lens needs a large aperture. This would conduce a severe non-uniformity on the illuminated area and a very low F-number. So it is rather difficult to design a singlet lens for LED illumination system with a better uniformity in certain area because of the non-uniform irradiation of the LED and the contradiction between the focal length and the aperture. For an on-axial point source, the spherical aberrations in different apertures can change the propagating direction of the rays; therefore it is possible to get a uniform illumination with the help of spherical aberrations. Light density function on the illuminated plan is deduced, and the merit function for uniform illumination in certain area is defined in this paper. By using the optical design software ZEMAX EE, the search of the optimal value for the given focal length is done. The computer simulation results show that by producing spherical aberrations correctly a better uniformity illumination can be obtained on the illuminated area in certain distance successfully.

  6. Automatic illumination compensation device based on a photoelectrochemical biofuel cell driven by visible light.

    PubMed

    Yu, You; Han, Yanchao; Xu, Miao; Zhang, Lingling; Dong, Shaojun

    2016-04-28

    Inverted illumination compensation is important in energy-saving projects, artificial photosynthesis and some forms of agriculture, such as hydroponics. However, only a few illumination adjustments based on self-powered biodetectors that quantitatively detect the intensity of visible light have been reported. We constructed an automatic illumination compensation device based on a photoelectrochemical biofuel cell (PBFC) driven by visible light. The PBFC consisted of a glucose dehydrogenase modified bioanode and a p-type semiconductor cuprous oxide photocathode. The PBFC had a high power output of 161.4 μW cm(-2) and an open circuit potential that responded rapidly to visible light. It adjusted the amount of illumination inversely irrespective of how the external illumination was changed. This rational design of utilizing PBFCs provides new insights into automatic light adjustable devices and may be of benefit to intelligent applications.

  7. Developing ultraviolet illumination of gillnets as a method to reduce sea turtle bycatch.

    PubMed

    Wang, John; Barkan, Joel; Fisler, Shara; Godinez-Reyes, Carlos; Swimmer, Yonat

    2013-10-23

    Fisheries bycatch of marine animals has been linked to population declines of multiple species, including many sea turtles. Altering the visual cues associated with fishing gear may reduce sea turtle bycatch. We examined the effectiveness of illuminating gillnets with ultraviolet (UV) light-emitting diodes for reducing green sea turtle (Chelonia mydas) interactions. We found that the mean sea turtle capture rate was reduced by 39.7% in UV-illuminated nets compared with nets without illumination. In collaboration with commercial fishermen, we tested UV net illumination in a bottom-set gillnet fishery in Baja California, Mexico. We did not find any difference in overall target fish catch rate or market value between net types. These findings suggest that UV net illumination may have applications in coastal and pelagic gillnet fisheries to reduce sea turtle bycatch.

  8. Effects of color combination and ambient illumination on visual perception time with TFT-LCD.

    PubMed

    Lin, Chin-Chiuan; Huang, Kuo-Chen

    2009-10-01

    An empirical study was carried out to examine the effects of color combination and ambient illumination on visual perception time using TFT-LCD. The effect of color combination was broken down into two subfactors, luminance contrast ratio and chromaticity contrast. Analysis indicated that the luminance contrast ratio and ambient illumination had significant, though small effects on visual perception. Visual perception time was better at high luminance contrast ratio than at low luminance contrast ratio. Visual perception time under normal ambient illumination was better than at other ambient illumination levels, although the stimulus color had a confounding effect on visual perception time. In general, visual perception time was better for the primary colors than the middle-point colors. Based on the results, normal ambient illumination level and high luminance contrast ratio seemed to be the optimal choice for design of workplace with video display terminals TFT-LCD.

  9. Developing ultraviolet illumination of gillnets as a method to reduce sea turtle bycatch

    PubMed Central

    Wang, John; Barkan, Joel; Fisler, Shara; Godinez-Reyes, Carlos; Swimmer, Yonat

    2013-01-01

    Fisheries bycatch of marine animals has been linked to population declines of multiple species, including many sea turtles. Altering the visual cues associated with fishing gear may reduce sea turtle bycatch. We examined the effectiveness of illuminating gillnets with ultraviolet (UV) light-emitting diodes for reducing green sea turtle (Chelonia mydas) interactions. We found that the mean sea turtle capture rate was reduced by 39.7% in UV-illuminated nets compared with nets without illumination. In collaboration with commercial fishermen, we tested UV net illumination in a bottom-set gillnet fishery in Baja California, Mexico. We did not find any difference in overall target fish catch rate or market value between net types. These findings suggest that UV net illumination may have applications in coastal and pelagic gillnet fisheries to reduce sea turtle bycatch. PMID:23883577

  10. Content-based fused off-axis object illumination direct-to-digital holography

    DOEpatents

    Price, Jeffery R.

    2006-05-02

    Systems and methods are described for content-based fused off-axis illumination direct-to-digital holography. A method includes calculating an illumination angle with respect to an optical axis defined by a focusing lens as a function of data representing a Fourier analyzed spatially heterodyne hologram; reflecting a reference beam from a reference mirror at a non-normal angle; reflecting an object beam from an object the object beam incident upon the object at the illumination angle; focusing the reference beam and the object beam at a focal plane of a digital recorder to from the content-based off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; and digitally recording the content based off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis.

  11. Morphological Background Detection and Illumination Normalization of Text Image with Poor Lighting

    PubMed Central

    Wang, Guocheng; Wang, Yiwen; Li, Hui; Chen, Xuanqi; Lu, Haitao; Ma, Yanpeng; Peng, Chun; Wang, Yijun; Tang, Linyao

    2014-01-01

    In this paper, some morphological transformations are used to detect the unevenly illuminated background of text images characterized by poor lighting, and to acquire illumination normalized result. Based on morphologic Top-Hat transform, the uneven illumination normalization algorithm has been carried out, and typically verified by three procedures. The first procedure employs the information from opening based Top-Hat operator, which is a classical method. In order to optimize and perfect the classical Top-Hat transform, the second procedure, featuring the definition of multi direction illumination notion, utilizes opening by reconstruction and closing by reconstruction based on multi direction structuring elements. Finally, multi direction images are merged to the final even illumination image. The performance of the proposed algorithm is illustrated and verified through the processing of different ideal synthetic and camera collected images, with backgrounds characterized by poor lighting conditions. PMID:25426639

  12. Morphological background detection and illumination normalization of text image with poor lighting.

    PubMed

    Wang, Guocheng; Wang, Yiwen; Li, Hui; Chen, Xuanqi; Lu, Haitao; Ma, Yanpeng; Peng, Chun; Wang, Yijun; Tang, Linyao

    2014-01-01

    In this paper, some morphological transformations are used to detect the unevenly illuminated background of text images characterized by poor lighting, and to acquire illumination normalized result. Based on morphologic Top-Hat transform, the uneven illumination normalization algorithm has been carried out, and typically verified by three procedures. The first procedure employs the information from opening based Top-Hat operator, which is a classical method. In order to optimize and perfect the classical Top-Hat transform, the second procedure, featuring the definition of multi direction illumination notion, utilizes opening by reconstruction and closing by reconstruction based on multi direction structuring elements. Finally, multi direction images are merged to the final even illumination image. The performance of the proposed algorithm is illustrated and verified through the processing of different ideal synthetic and camera collected images, with backgrounds characterized by poor lighting conditions.

  13. Second-harmonic illumination to enhance multispectral digital lensless holographic microscopy.

    PubMed

    Mendoza-Yero, Omel; Carbonell-Leal, Miguel; Lancis, Jesús; Garcia-Sucerquia, Jorge

    2016-03-01

    Multispectral digital lensless holographic microscopy (MDLHM) operating with second-harmonic illumination is shown. Added to the improvement of the spatial resolution of the previously reported MDLHM operating with near-infrared illumination, this second-harmonic MDLHM shows promise as a tool to study the behavior of biological samples under a broad spectral illumination. This illumination is generated by focusing a highly spatially coherent ultrashort pulsed radiation into an uncoated Type 1 β-BaB2O4 (BBO) nonlinear crystal. The second-harmonic MDLHM allows achieving multispectral images of biological samples with enhanced micrometer spatial resolution. The illumination wavelength of the second-harmonic MDLHM can be tuned by displacing a focusing optics with respect to a pinhole; spatially resolved information at different wavelengths of the sample can then be retrieved.

  14. Illumination analysis of the digital pattern recognition system by Bessel masks and one-dimensional signatures

    NASA Astrophysics Data System (ADS)

    Solorza, S.; Álvarez-Borrego, J.

    2013-11-01

    The effects of illumination variations in digital images are a trend topic of the pattern recognition field. The luminance information of the objects help to classify them, however the environment illumination could cause a lot of problem if the system is not illumination invariant. Some applications of this topic include image and video quality, biometrics classification, etc. In this work an illumination analysis for a digital system invariant to position and rotation based on Fourier transform, Bessel masks, one-dimensional signatures and linear correlations are presented. The digital system was tested using a reference database of 21 fossil diatoms images of gray-scale and 307 x 307 pixels. The digital system has shown an excellent performance in the classification of 60,480 problem images which have different non-homogeneous illumination.

  15. The effect of illumination and time of day on movements of bobcats (Lynx rufus).

    PubMed

    Rockhill, Aimee P; DePerno, Christopher S; Powell, Roger A

    2013-01-01

    Understanding behavioral changes of prey and predators based on lunar illumination provides insight into important life history, behavioral ecology, and survival information. The objectives of this research were to determine if bobcat movement rates differed by period of day (dark, moon, crepuscular, day), lunar illumination (<10%, 10 - <50%, 50 - <90%, >90%), and moon phase (new, full). Bobcats had high movement rates during crepuscular and day periods and low movement rates during dark periods with highest nighttime rates at 10-<50% lunar illumination. Bobcats had highest movement rates during daytime when nighttime illumination was low (new moon) and higher movement rates during nighttime when lunar illumination was high (full moon). The behaviors we observed are consistent with prey availability being affected by light level and by limited vision by bobcats during darkness.

  16. Hybrid daylight/light-emitting diode illumination system for indoor lighting.

    PubMed

    Ge, Aiming; Qiu, Peng; Cai, Jinlin; Wang, Wei; Wang, Junwei

    2014-03-20

    A hybrid illumination method using both daylight and light-emitting diodes (LEDs) for indoor lighting is presented in this study. The daylight can be introduced into the indoor space by a panel-integration system. The daylight part and LEDs are combined within a specific luminaire that can provide uniform illumination. The LEDs can be turned on and dimmed through closed-loop control when the daylight illuminance is inadequate. We simulated the illumination and calculated the indoor lighting efficiency of our hybrid daylight and LED lighting system, and compared this with that of LED and fluorescent lighting systems. Simulation results show that the efficiency of the hybrid daylight/LED illumination method is better than that of LED and traditional lighting systems, under the same lighting conditions and lighting time; the method has hybrid lighting average energy savings of T5 66.28%, and that of the LEDs is 41.62%.

  17. Eye-safe laser illuminators as less-than-lethal weapons

    NASA Astrophysics Data System (ADS)

    German, John D.; Adler, Dean S.

    1997-01-01

    Law enforcement and military forces are often faced with situations requiring less-than-lethal response options. Low- power, eye-safe laser illuminators have been shown to be effective, non-lethal weapons for a variety of law enforcement and other-than-war military applications. Through the effects of illumination, glare, and psychological impact; lasers can provide unequivocal warning, threat assessment based on reaction to the warning, hesitation, distraction, and reductions in combat and functional effectiveness. This paper discusses ongoing research and development by Science and Engineering Associates into laser illuminator concepts for civilian and military use. Topics include fundamental design and safety issues, laser diode requirements, and laser illuminator concepts, including a grenade shell laser system that converts a standard 40-mm grenade launcher into a laser illuminator.

  18. Capacity analyze of WDM indoor visible light communication based on LED for standard illumination

    NASA Astrophysics Data System (ADS)

    Huang, Heqing; Tang, Yi; Cui, Lu; Zhu, Qingwei; Luo, Jiabin

    2015-08-01

    For indoor visible light communication (VLC) systems aim to achieve communication and illumination simultaneously, the channel capacity are significantly affected by illumination demands in actual scenarios. To enhance the system performance, the wavelength division multiplex (WDM) technique can be introduced. In this letter, we analyzed the demands of illuminance and chromaticity's influence on indoor WDM visible light communication system based on color light emitting diodes (LED). The spectra distribution, crosstalk and noise of WDM VLC system were analyzed and the relative optimal total channel capacity was obtained by optimizing the number of sub-channels and their intensity at standard illumination scenario. It's shown that by applying WDM technique, the total channel capacity of LED based VLC system can be about 4 times than the situation of single sub-channel, even with indoor illumination constraints. What's more, the system performance can be improved by adjusting appropriate number of sub-channels and their intensity accordingly.

  19. A Probabilistic Method for Image Enhancement With Simultaneous Illumination and Reflectance Estimation.

    PubMed

    Fu, Xueyang; Liao, Yinghao; Zeng, Delu; Huang, Yue; Zhang, Xiao-Ping; Ding, Xinghao

    2015-12-01

    In this paper, a new probabilistic method for image enhancement is presented based on a simultaneous estimation of illumination and reflectance in the linear domain. We show that the linear domain model can better represent prior information for better estimation of reflectance and illumination than the logarithmic domain. A maximum a posteriori (MAP) formulation is employed with priors of both illumination and reflectance. To estimate illumination and reflectance effectively, an alternating direction method of multipliers is adopted to solve the MAP problem. The experimental results show the satisfactory performance of the proposed method to obtain reflectance and illumination with visually pleasing enhanced results and a promising convergence rate. Compared with other testing methods, the proposed method yields comparable or better results on both subjective and objective assessments.

  20. Automatic illumination compensation device based on a photoelectrochemical biofuel cell driven by visible light

    NASA Astrophysics Data System (ADS)

    Yu, You; Han, Yanchao; Xu, Miao; Zhang, Lingling; Dong, Shaojun

    2016-04-01

    Inverted illumination compensation is important in energy-saving projects, artificial photosynthesis and some forms of agriculture, such as hydroponics. However, only a few illumination adjustments based on self-powered biodetectors that quantitatively detect the intensity of visible light have been reported. We constructed an automatic illumination compensation device based on a photoelectrochemical biofuel cell (PBFC) driven by visible light. The PBFC consisted of a glucose dehydrogenase modified bioanode and a p-type semiconductor cuprous oxide photocathode. The PBFC had a high power output of 161.4 μW cm-2 and an open circuit potential that responded rapidly to visible light. It adjusted the amount of illumination inversely irrespective of how the external illumination was changed. This rational design of utilizing PBFCs provides new insights into automatic light adjustable devices and may be of benefit to intelligent applications.Inverted illumination compensation is important in energy-saving projects, artificial photosynthesis and some forms of agriculture, such as hydroponics. However, only a few illumination adjustments based on self-powered biodetectors that quantitatively detect the intensity of visible light have been reported. We constructed an automatic illumination compensation device based on a photoelectrochemical biofuel cell (PBFC) driven by visible light. The PBFC consisted of a glucose dehydrogenase modified bioanode and a p-type semiconductor cuprous oxide photocathode. The PBFC had a high power output of 161.4 μW cm-2 and an open circuit potential that responded rapidly to visible light. It adjusted the amount of illumination inversely irrespective of how the external illumination was changed. This rational design of utilizing PBFCs provides new insights into automatic light adjustable devices and may be of benefit to intelligent applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00759g

  1. The use of holographic and diffractive optics for optimized machine vision illumination for critical dimension inspection

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd E.; Ohar, Orest

    2004-02-01

    Illuminators used in machine vision applications typically produce non-uniform illumination onto the targeted surface being observed, causing a variety of problems with machine vision alignment or measurement. In most circumstances the light source is broad spectrum, leading to further problems with image quality when viewed through a CCD camera. Configured with a simple light bulb and a mirrored reflector and/or frosted glass plates, these general illuminators are appropriate for only macro applications. Over the last 5 years newer illuminators have hit the market including circular or rectangular arrays of high intensity light emitting diodes. These diode arrays are used to create monochromatic flood illumination of a surface that is to be inspected. The problem with these illumination techniques is that most of the light does not illuminate the desired areas, but broadly spreads across the surface, or when integrated with diffuser elements, tend to create similar shadowing effects to the broad spectrum light sources. In many cases a user will try to increase the performance of these illuminators by adding several of these assemblies together, increasing the intensity or by moving the illumination source closer or farther from the surface being inspected. In this case these non-uniform techniques can lead to machine vision errors, where the computer machine vision may read false information, such as interpreting non-uniform lighting or shadowing effects as defects. This paper will cover a technique involving the use of holographic / diffractive hybrid optical elements that are integrated into standard and customized light sources used in the machine vision industry. The bulk of the paper will describe the function and fabrication of the holographic/diffractive optics and how they can be tailored to improve illuminator design. Further information will be provided a specific design and examples of it in operation will be disclosed.

  2. An Illumination Modeling System for Human Factors Analyses

    NASA Technical Reports Server (NTRS)

    Huynh, Thong; Maida, James C.; Bond, Robert L. (Technical Monitor)

    2002-01-01

    Seeing is critical to human performance. Lighting is critical for seeing. Therefore, lighting is critical to human performance. This is common sense, and here on earth, it is easily taken for granted. However, on orbit, because the sun will rise or set every 45 minutes on average, humans working in space must cope with extremely dynamic lighting conditions. Contrast conditions of harsh shadowing and glare is also severe. The prediction of lighting conditions for critical operations is essential. Crew training can factor lighting into the lesson plans when necessary. Mission planners can determine whether low-light video cameras are required or whether additional luminaires need to be flown. The optimization of the quantity and quality of light is needed because of the effects on crew safety, on electrical power and on equipment maintainability. To address all of these issues, an illumination modeling system has been developed by the Graphics Research and Analyses Facility (GRAF) and Lighting Environment Test Facility (LETF) in the Space Human Factors Laboratory at NASA Johnson Space Center. The system uses physically based ray tracing software (Radiance) developed at Lawrence Berkeley Laboratories, a human factors oriented geometric modeling system (PLAID) and an extensive database of humans and environments. Material reflectivity properties of major surfaces and critical surfaces are measured using a gonio-reflectometer. Luminaires (lights) are measured for beam spread distribution, color and intensity. Video camera performances are measured for color and light sensitivity. 3D geometric models of humans and the environment are combined with the material and light models to form a system capable of predicting lighting conditions and visibility conditions in space.

  3. Post-illumination Pupil Response in Subjects without Ocular Disease

    PubMed Central

    Kankipati, Laxmikanth; Girkin, Christopher A.; Gamlin, Paul D.

    2010-01-01

    Purpose. A sustained pupilloconstriction is often observed after the cessation of a bright visual stimulus. This post-illumination pupil response (PIPR) is produced by the intrinsically photosensitive retinal ganglion cells (ipRGCs). The present study was designed to examine the characteristics of the PIPR in a normal population without ocular disease. Methods. Thirty-seven subjects (mean age, 48.6 years) were tested by presenting a 60°, 10-second light stimulus (13 log quanta/cm2/s retinal irradiance) and recording pupillary responses for 50 seconds after light cessation. The light stimuli (470 [blue] and 623 [red] nm) were presented by an optical system to one eye after dilation, while the consensual pupil response of the fellow, undilated eye was recorded by infrared pupillometry. Results. A positive PIPR was seen in all subjects tested. The population average of the PIPR for 470-nm light was 1.5 mm (SEM 0.10, P < 0.05) and the net PIPR (blue PIPR minus red PIPR) was 1.4 mm (SEM 0.09, P < 0.0001). The net PIPR correlated positively with baseline pupil diameter (P < 0.05), but not significantly with age, race, or sex (P > 0.05) in the test population. Conclusions. All normal subjects displayed a significant PIPR for a 10-second, 470-nm light stimulus, but not a 623-nm stimulus, which is consistent with the proposed melanopsin-mediated response. In most normal individuals, the amplitude of the PIPR was substantial. This test has the potential to be used as a tool in evaluating subjects with inner retinal dysfunction or melanopsin-related disorders. PMID:20007832

  4. Targeted illumination and tracking using optical fiber probe for optogenetics application

    NASA Astrophysics Data System (ADS)

    Shinde, Anant; Perinchery, Sandeep M.; Matham, Murukeshan V.

    2016-03-01

    There was a renewed interest, during the recent years, in the imaging and tracking of targeted cells or organelles for a variety of biomedical and lab-on a chip applications that include particles movement. However, nonspecific illumination during tracking can have adverse effects such as heating, reduced image contrast and photo bleaching. In fact, current available tracking and imaging systems are unable to selectively illuminate the particle being tracked. To fill this void, we have developed a fiber optics based probe system incorporating a spatial light modulator (SLM) and an imaging fiber bundle for selective illumination on the targeted particle. A GRIN lens is attached at the distal endface of the image fiber bundle for optimised illumination and collection. A tracking algorithm is developed in order to enable controlled illumination through SLM to target the illumination point or location in accordance with the particle movement and size variation. Further with this probe, particles can be illuminated with light pulses of controllable duty cycle and frequency. The proposed methodology and developed probe have good significance and expected to find potential applications areas such as optogenetics, cell signalling studies, and lab-on a chip systems.

  5. Trans-illuminated laser speckle imaging of collateral artery blood flow in ischemic mouse hindlimb.

    PubMed

    Meisner, Joshua K; Niu, Jacqueline; Sumer, Suna; Price, Richard J

    2013-09-01

    The mouse ischemic hindlimb model is used widely for studying collateral artery growth (i.e., arteriogenesis) in response to increased shear stress. Nonetheless, precise measurements of regional shear stress changes along individual collateral arteries are lacking. Our goal is to develop and verify trans-illumination laser speckle flowmetry (LSF) for this purpose. Studies of defibrinated bovine blood flow through tubes embedded in tissue-mimicking phantoms indicate that trans-illumination LSF better maintains sensitivity with an increasing tissue depth when compared to epi-illumination, with an ∼50% reduction in the exponential decay of the speckle velocity signal. Applying trans-illuminated LSF to the gracilis muscle collateral artery network in vivo yields both improved sensitivity and reduced noise when compared to epi-illumination. Trans-illuminated LSF images reveal regional differences in collateral artery blood velocity after femoral artery ligation and are used to measure an ∼2-fold increase in the shear stress at the entrance regions to the muscle. We believe these represent the first direct measurements of regional shear stress changes in individual mouse collateral arteries. The ability to capture deeper vascular signals using a trans-illumination configuration for LSF may expand the current applications for LSF, which could have bearing on determining how shear stress magnitude and direction regulate arteriogenesis.

  6. Method for site characterization of anisotropic diffuse illumination of photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Russo, Juan M.; Zhang, Deming; Vorndran, Shelby; Gordon, Michael; Castillo, Jose; Brooks, Adria; Lonij, Vincent; Cronin, Alex; Kostuk, Raymond

    2012-10-01

    In this paper a method to characterize the anisotropy of diffuse illumination incident on photovoltaic systems is presented. PV systems are designed based on standard conditions in which only consider direct and isotropic diffuse illumination. Anisotropic illumination can cause the PV system output to step outside of the design specifications. A baffled multi-detector sensor system is described having a discrete set of azimuthal and declination angle combinations in order to constantly sample the irradiance and the incidence angle of the diffuse illumination in all zenith directions. The sensor was deployed in the Tucson Electric Power Solar Test Yard alongside with commercially available PV systems that are independently monitored. Constant and transient sources of anisotropic diffuse illumination, such as surface reflection and cloud edge effects respectively, are measured and modeled with ray tracing software. Results of the method are described for characterizing diffuse illumination at the TEP Solar Test Yard. Understanding the anisotropic diffuse illumination can potentially allow to more accurately predict PV system or to optimize energy harvesting of systems with non-standard mounting conditions as well as building integrated photovoltaic applications.

  7. Object-based illumination normalization for multi-temporal satellite images in urban area

    NASA Astrophysics Data System (ADS)

    Su, Nan; Zhang, Ye; Tian, Shu; Yan, Yiming

    2016-09-01

    Multi-temporal satellite images acquisition with different illumination conditions cause radiometric difference to have a huge effect on image quality during remote sensing image processing. In particular, image matching of satellite stereo images with great difference between acquisition dates is very difficult for the high-precision DSM generation in the field of satellite photogrammetry. Therefore, illumination normalization is one of the greatest application technology to eliminate radiometric difference for image matching and other image applications. In this paper, we proposed a novel method of object-based illumination normalization to improve image matching of different temporal satellite stereo images in urban area. Our proposed method include two main steps: 1) the object extraction 2) multi-level illumination normalization. Firstly, we proposed a object extraction method for the same objects extraction among the multi-temporal satellite images, which can keep the object structural attribute. Moreover, the multi-level illumination normalization is proposed by combining gradient domain method and singular value decomposition (SVD) according to characteristic information of relevant objects. Our proposed method has great improvement for the illumination of object area to be benefit for image matching in urban area with multiple objects. And the histogram similarity parameter and matching rate are used for illumination consistency quantitative evaluation. The experiments have been conducted on different satellite images with different acquisition dates in the same urban area to verify the effectiveness of our proposed method. The experimental results demonstrate a good performance by comparing other methods.

  8. Robust estimation of albedo for illumination-invariant matching and shape recovery.

    PubMed

    Biswas, Soma; Aggarwal, Gaurav; Chellappa, Rama

    2009-05-01

    We present a nonstationary stochastic filtering framework for the task of albedo estimation from a single image. There are several approaches in the literature for albedo estimation, but few include the errors in estimates of surface normals and light source direction to improve the albedo estimate. The proposed approach effectively utilizes the error statistics of surface normals and illumination direction for robust estimation of albedo, for images illuminated by single and multiple light sources. The albedo estimate obtained is subsequently used to generate albedo-free normalized images for recovering the shape of an object. Traditional Shape-from-Shading (SFS) approaches often assume constant/piecewise constant albedo and known light source direction to recover the underlying shape. Using the estimated albedo, the general problem of estimating the shape of an object with varying albedo map and unknown illumination source is reduced to one that can be handled by traditional SFS approaches. Experimental results are provided to show the effectiveness of the approach and its application to illumination-invariant matching and shape recovery. The estimated albedo maps are compared with the ground truth. The maps are used as illumination-invariant signatures for the task of face recognition across illumination variations. The recognition results obtained compare well with the current state-of-the-art approaches. Impressive shape recovery results are obtained using images downloaded from the Web with little control over imaging conditions. The recovered shapes are also used to synthesize novel views under novel illumination conditions.

  9. The optimal design of TIR lens for improving LED illumination uniformity and efficiency

    NASA Astrophysics Data System (ADS)

    Zhen, Yankun; Jia, Zhenan; Zhang, Wenzi

    2008-03-01

    With the development of LED technology, LED will potentially replace the traditional light source for its cost and size advantages, especially in the micro-projection system. And since the illumination uniformity and efficiency on spatial light modulators (SLM) are two important factors in evaluating the performance of micro-projection system, tapered light pipe (TLP) and square compound parabolic concentrator (SCPC) are often used as beam shaper in LED-based micro projection system to provide SLM with uniform and efficient illumination. In this paper, in order to overcome the disadvantage of insufficient compactness induced by the working length of TLP or SCPC for the illumination system, a total internal reflection (TIR) lens with rotated and faceted structure is designed with an optimization method to couple and transfer most of the light emitted from LED into a rectangular target plane (RTP) representing SLM. The TIR lens has six surfaces controlled by 17 dimensional parameters and is designed by optimization of dimensional parameters with generic algorithms. In order to provide RTP in fixed position with satisfied illumination uniformity and efficiency, the illumination uniformity and efficiency on RTP are taken into account in the merit function for the optimization process. In Tracepro program, the simulation result of the LED illumination system with the optimized TIR lens shows that the illumination efficiency and uniformity has respectively achieved to 61.9%, 76% with considering the limitation angle of light (15°).

  10. The Influence of Very Low Illumination on the Postural Sway of Young and Elderly Adults

    PubMed Central

    Rugelj, Darja; Gomišček, Gregor; Sevšek, France

    2014-01-01

    The purpose of the present study was to evaluate the influence of very low ambient illumination and complete darkness on the postural sway of young and elderly adults. Eighteen healthy young participants aged 23.8±1.5 years and 26 community-dwelling elderly aged 69.8±5.6 years were studied. Each participant performed four tests while standing on a force platform in the following conditions: in normal light (215 lx) with open eyes and with closed eyes, in very low illumination (0.25 lx) with open eyes, and in complete darkness with open eyes. The sequences of the tests in the altered visual conditions were determined by random blocs. Postural sway was assessed by means of the force platform measurements. The centre of pressure variables: the medio-lateral and antero-posterior path lengths, mean velocities, sway areas, and fractal dimensions were analysed. Very low illumination resulted in a statistically significant increase in postural sway in both the young and elderly groups compared to normal light, although the increase was significantly smaller than those observed in the eyes closed and complete darkness condition, and no significant effects of illumination on fractal dimensions were detected. The gains of the sways in the very low or no illumination conditions relative to the normal light condition were significantly larger in the group of young participants than in the group of elderly participants (up to 50% and 25%, respectively). However, the response patterns to changes in illumination were similar in the young and elderly participants, with the exception of the short-range fractal dimension of the medio-lateral sway. In conclusion, very low illumination resulted in increased postural sway compared to normal illumination; however, in the closed eye and complete darkness conditions, postural sway was significantly higher than in the very low illumination condition regardless of the age of the participants. PMID:25084015

  11. A bright and long-pulse illumination for ultrahigh-speed microscopy of living specimens.

    PubMed

    Nakano, Hitoshi; Yokoi, Sayoko; Yoshida, Shigeru; Yamada, Makoto; Takeuchi, Takeshi; Takehara, Kosei; Etoh, T Goji

    2010-01-01

    Ultrahigh-speed microscopy of living specimens requires ultrabright illumination. Moreover, the duration of illumination should be sufficiently long, on the order of at least several tens of milliseconds, in order to investigate the dynamic state of living specimens. However, specimens are exposed to a high risk of damage by the intense illumination. The brightness and pulse duration of illumination have to be continuously controlled for use in the ultrahigh-speed microscopy of living specimens. Commercial or laboratory-made illumination systems do not satisfy the abovementioned requirements. In this paper, the development of a bright and long-pulse illumination system for ultrahigh-speed microscopy of living specimens is presented. A xenon flashlamp with an arc length of 1.5 mm has been used as the light source. The electrical power supply consists of a voltage-regulated circuit, a capacitor bank, and a control circuit including an insulated-gate bipolar transistor as a gating device, which provides a large rectangular current pulse with the duration in the range to the order of several tens of milliseconds. The brightness, pulse duration, and repetition rate can be easily and continuously controlled. The illumination developed in the present study is installed in an inverted fluorescence microscope equipped with a high-speed camera in order to evaluate the performance as an illumination source. A fluorescent image of the living spermatozoa of a mouse obtained at a frame rate of 8 kHz shows good contrast. Such an image cannot be obtained using a commercial illumination system.

  12. A bright and long-pulse illumination for ultrahigh-speed microscopy of living specimens

    NASA Astrophysics Data System (ADS)

    Nakano, Hitoshi; Yokoi, Sayoko; Yoshida, Shigeru; Yamada, Makoto; Takeuchi, Takeshi; Takehara, Kosei; Etoh, T. Goji

    2010-01-01

    Ultrahigh-speed microscopy of living specimens requires ultrabright illumination. Moreover, the duration of illumination should be sufficiently long, on the order of at least several tens of milliseconds, in order to investigate the dynamic state of living specimens. However, specimens are exposed to a high risk of damage by the intense illumination. The brightness and pulse duration of illumination have to be continuously controlled for use in the ultrahigh-speed microscopy of living specimens. Commercial or laboratory-made illumination systems do not satisfy the abovementioned requirements. In this paper, the development of a bright and long-pulse illumination system for ultrahigh-speed microscopy of living specimens is presented. A xenon flashlamp with an arc length of 1.5 mm has been used as the light source. The electrical power supply consists of a voltage-regulated circuit, a capacitor bank, and a control circuit including an insulated-gate bipolar transistor as a gating device, which provides a large rectangular current pulse with the duration in the range to the order of several tens of milliseconds. The brightness, pulse duration, and repetition rate can be easily and continuously controlled. The illumination developed in the present study is installed in an inverted fluorescence microscope equipped with a high-speed camera in order to evaluate the performance as an illumination source. A fluorescent image of the living spermatozoa of a mouse obtained at a frame rate of 8 kHz shows good contrast. Such an image cannot be obtained using a commercial illumination system.

  13. Energy feedback freeform lenses for uniform illumination of extended light source LEDs.

    PubMed

    Li, Zongtao; Yu, Shudong; Lin, Liwei; Tang, Yong; Ding, Xinrui; Yuan, Wei; Yu, Binhai

    2016-12-20

    Using freeform lenses to construct uniform illumination systems is important in light-emitting diode (LED) devices. In this paper, the energy feedback design is used for freeform lens (EFFL) constructions by solving a set of partial differential equations that describe the mapping relationships between the source and the illumination pattern. The simulation results show that the method can overcome the illumination deviation caused by the extended light source (ELS) problem. Furthermore, a uniformity of 95.6% is obtained for chip-on-board (COB) compact LED devices. As such, prototype LEDs manufactured with the proposed freeform lenses demonstrate significant improvements in luminous efficiency and emission uniformity.

  14. A recommendation for illumination of the Farnsworth-Munsell 100-hue test.

    PubMed

    Bowman, K J; Cole, B L

    1980-11-01

    The effect of illuminance on the performance of the Farnsworth-Munsell 100-hue (FM 100) test has previously been reported for young observers with normal color vision. However, information regarding these effects for older persons is lacking. This study reports the effect of illuminance level, over a wide range, on the FM100 performance of 10 elderly subjects with normal color vision compared to a control group of five young adult normal subjects. A recommendation is made for a standard level of illuminance for administration of the FM100-hue test.

  15. A bilateral comparison on illuminance using a photometer between IPT and LABELO

    NASA Astrophysics Data System (ADS)

    Ferreira Junior, A. F. G.; Bindé Junior, C. J. R.

    2016-07-01

    This work presents the result of bilateral illuminance comparison obtained from a photometer calibration. The bilateral comparison was performed comparing the calibration results from the same photometer at LABELO and IPT laboratories, which take part of Brazilian calibration network. Occasionally LABELO was chosen as a pilot laboratory and was responsible to calibrate the photometer at the beginning and end of comparison and define the reference illuminance value of photometer calibration. The illuminance calibration points ranged from 20 to 2000 lx and the comparison evaluation criterion was the normalized error (En numbers). The laboratory measurements are in agreement according to the evaluation criterion.

  16. Lensless coherent imaging by phase retrieval with an illumination pattern constraint.

    PubMed

    Fienup, James R

    2006-01-23

    It is often possible to reduce the requirements on an imaging system by placing greater demands either on an illumination system or on post-detection processing of the data collected by the system. An extreme example of this is a system with no receiver optics whatsoever. By illuminating an object or scene with coherent light having a shaped illumination pattern, the receiver can be a simple detector array with no imaging optics, detecting the speckle intensity pattern reflected from the object; an image of the object can be reconstructed by a phase retrieval algorithm.

  17. Design of a high-efficiency collection structure for daylight illumination applications.

    PubMed

    Tsai, Meng-Che; Whang, Allen Jong-Woei; Lee, Tsung-Xian

    2013-12-20

    In developing a high-quality natural light illumination system (NLIS), the primary considerations include how to increase system efficiency and broaden its applications. This paper describes the conception, design, and analysis of a daylight collector that presents the combined advantages of excellent efficiency and a compact size. The collector structure consists of extendable two-channel collecting units, a planar light guide, and a central coupler to improve light collection efficiency and increase surface area. In this study, two types of daylight collectors are proposed for illumination applications with different light patterns. With these collectors, the NLIS can now provide sufficiently powerful light for indoor illumination.

  18. Analysis of array illumination generalized by the combination of a binary phase grating and a lens

    NASA Astrophysics Data System (ADS)

    Wang, Huai-sheng

    2007-12-01

    In this paper we propose a method to use a binary phase and a lens to fulfil array illumination. An equation is given to research the array illumination by a given binary phase grating and a lens. We use a lens with the two main excellences. One is that, the lens can raise the intensity of reflected light from a reflective object. Sometime the reflected light is too weak to be recorded. The other is the spatial structure to be conveniently adjusted by the binary phase grating and the lens. Thus industry measurement relevant to array illumination is more easily carried out.

  19. Low-temperature illumination and annealing of ultrahigh quality quantum wells

    NASA Astrophysics Data System (ADS)

    Samani, M.; Rossokhaty, A. V.; Sajadi, E.; Lüscher, S.; Folk, J. A.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.

    2014-09-01

    The effects of low-temperature illumination and annealing on fractional quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are investigated. Illumination alone, below 1 K, decreases the density of the two-dimensional electron gas (2DEG) electrons by more than an order of magnitude and resets the sample to a repeatable initial state. Subsequent thermal annealing at a few Kelvin restores the original density and dramatically improves FQH characteristics. A reliable illumination and annealing recipe is developed that yields an energy gap of 600 mK for the 5/2 state.

  20. Mutual Comparative Filtering for Change Detection in Videos with Unstable Illumination Conditions

    NASA Astrophysics Data System (ADS)

    Sidyakin, Sergey V.; Vishnyakov, Boris V.; Vizilter, Yuri V.; Roslov, Nikolay I.

    2016-06-01

    In this paper we propose a new approach for change detection and moving objects detection in videos with unstable, abrupt illumination changes. This approach is based on mutual comparative filters and background normalization. We give the definitions of mutual comparative filters and outline their strong advantage for change detection purposes. Presented approach allows us to deal with changing illumination conditions in a simple and efficient way and does not have drawbacks, which exist in models that assume different color transformation laws. The proposed procedure can be used to improve a number of background modelling methods, which are not specifically designed to work under illumination changes.

  1. In vivo deep brain imaging of rats using oral-cavity illuminated photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    Lin, Li; Xia, Jun; Wong, Terence T. W.; Zhang, Ruiying; Wang, Lihong V.

    2015-03-01

    We demonstrate, by means of internal light delivery, photoacoustic imaging of the deep brain of rats in vivo. With fiber illumination via the oral cavity, we delivered light directly into the bottom of the brain, much more than can be delivered by external illumination. The study was performed using a photoacoustic computed tomography (PACT) system equipped with a 512-element full-ring transducer array, providing a full two-dimensional view aperture. Using internal illumination, the PACT system provided clear cross sectional photoacoustic images from the palate to the middle brain of live rats, revealing deep brain structures such as the hypothalamus, brain stem, and cerebral medulla.

  2. In vivo deep brain imaging of rats using oral-cavity illuminated photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    Lin, Li; Xia, Jun; Wong, Terence T. W.; Li, Lei; Wang, Lihong V.

    2015-01-01

    Using internal illumination with an optical fiber in the oral cavity, we demonstrate, for the first time, photoacoustic computed tomography (PACT) of the deep brain of rats in vivo. The experiment was performed on a full-ring-array PACT system, with the capability of providing high-speed cross-sectional imaging of the brain. Compared with external illumination through the cranial skull, internal illumination delivers more light to the base of the brain. Consequently, in vivo photoacoustic images clearly reveal deep brain structures such as the hypothalamus, brain stem, and cerebral medulla.

  3. Padua and the Stars: Medieval Painting and Illuminated Manuscripts

    NASA Astrophysics Data System (ADS)

    Canova, G. M.

    2011-06-01

    In the Middle Ages, the University of Padua was one of the most prominent centre for astrological studies in Europe. The Paduan doctor and philosopher, Pietro d'Abano, who lived in the first decades of the 14th century, was the main figure in this field. At the end of the 13th century, during a long stay in Paris, he got in contact with the new astrological doctrines flourished after the translation into Latin of Ptolemy's and Arab's works in Spain. Thus, when he went back to Padua, he published several studies on the influence of celestial bodies on human life and human physical characteristics and psychology. These ideas deeply affected the Paduan society of the 14th century and, consequently, the most important painters chose or were asked to evoke the images of stars, planets, and their properties. This adventure began with Giotto who shows a surprising interest in celestial bodies in the Scrovegni Chapel where he represented a comet, and soon after he produced a cycle of astrological paintings on the vault of the Palazzo della Ragione in the Public Palace of Padua. Unfortunately, in 1420, these paintings were destroyed in a fire, but the magnificent cycle of astrological frescoes realized soon after on the walls of the same room gives us some clues on Giotto's work and shows us the complexity of the Medieval astrological science. Other astrological paintings, still preserved, were realized by the painters of the Carrarese Court such as Guariento, who painted the planets and their influences on human ages in the church of the Eremitani, and Giusto dei Menabuoi who represented a superb zodiac around a realistic map of Earth in the Cathedral Baptistery. So Padua really became the capital of astrological painting in Europe. Other evidence of the astrological image in the Veneto Region, between the 14th and 15th centuries, can be found in the manuscripts illuminated in the milieu of the University of Padua and in the first books printed in Venice.

  4. 49 CFR 214.509 - Required visual illumination and reflective devices for new on-track roadway maintenance machines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Required visual illumination and reflective... Required visual illumination and reflective devices for new on-track roadway maintenance machines. Each new on-track roadway maintenance machine shall be equipped with the following visual illumination...

  5. 10 CFR 431.204 - Uniform test method for the measurement of energy consumption of illuminated exit signs.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... consumption of illuminated exit signs. 431.204 Section 431.204 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Illuminated Exit Signs Test Procedures § 431.204 Uniform test method for the measurement of energy consumption of illuminated exit...

  6. 10 CFR 431.204 - Uniform test method for the measurement of energy consumption of illuminated exit signs.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... consumption of illuminated exit signs. 431.204 Section 431.204 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Illuminated Exit Signs Test Procedures § 431.204 Uniform test method for the measurement of energy consumption of illuminated exit...

  7. Degradation of near infrared and shortwave infrared imager performance due to atmospheric scattering of diffuse night illumination.

    PubMed

    Vollmerhausen, Richard

    2013-07-20

    On moonless nights, airglow is the primary source of natural ground illumination in the near infrared and shortwave infrared spectral bands. Therefore, night vision imagers operating in these spectral bands view targets that are diffusely illuminated. Aerosol scattering of diffuse airglow illumination causes atmospheric path radiance and that radiance causes increased imager noise. These phenomena and their quantification are described in this paper.

  8. Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

    NASA Astrophysics Data System (ADS)

    Costescu, Ruxandra M.; Deneke, Christoph; Thurmer, Dominic J.; Schmidt, Oliver G.

    2009-12-01

    The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The “etch suppression” area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

  9. Study of adaptive LLL/infrared image color fusion algorithm based on the environment illumination

    NASA Astrophysics Data System (ADS)

    Hu, Qing-ping; Zhang, Xiao-hui; Liu, Chao

    2016-10-01

    LLL (Low-light-level) / infrared image fusion can integrate both bands information of the target, it is beneficial for target detection and scene perception in the low visibility weather such as night, haze, rain, and snow. The quality of fused image is declined, when any channel image quality drops. There will be great changes in the brightness, contrast and noise on LLL images when environment illumination has obvious changes, but the current color fusion methods is not adapted to the environment illumination change in larger dynamic range. In this paper, LLL image characteristics are analyzed under different environment illumination, and a kind of adaptive color fusion method is proposed based on the RGB color space. The fused image can get better brightness and signal-to-noise ratio under the different intensity of illumination.

  10. Dynamics of the light-induced atomic desorption at homogeneous illumination

    NASA Astrophysics Data System (ADS)

    Tsvetkov, S.; Taslakov, M.; Gateva, S.

    2017-03-01

    An experimental investigation of Light-Induced Atomic Desorption (LIAD) at homogeneous illumination in uncoated Rb glass cell is reported. The dynamics parameters of LIAD and their dependences on the illumination intensity in uncoated cell are measured and compared with these in paraffin-coated cell and the theoretical dependences for coated cell at homogeneous illumination. The homogeneous illumination not only increases the yield of LIAD, but increases the rates of desorption and adsorption. The results are interesting for the better understanding of the process of LIAD and the atom-surface interaction, for the development of new LIAD-loaded atomic devices, all-optical control of light, optical sensors miniaturization, and new methods for surface and coating diagnostics and nanostructuring.

  11. Investigation of Relative Illuminance as a Function of Distance between Reflector and Fluorescent Light Source

    NASA Astrophysics Data System (ADS)

    Softic, Amela

    2007-04-01

    Although fluorescent lighting is considerably more efficient then incandescent, and is in wide use, manufacturers find new ways to improve its configuration and reduce energy use. Based on the fundamentals of ``Non-imaging Optics'', was experimentally investigated the dependence of illumination of a point in the space on the distance between the reflection and fluorescent light source. Monitoring of changes in illumination is performed by optical sensor and corresponding computer software. Investigation of the influence of the distance between the fluorescent light and the reflector on the relative illumination has shown, for the tested geometries, that by reducing the distance between them the illumination increased, even though the distance among the source and the measuring point got greater.

  12. Changes of flavonoid content and antioxidant capacity in blueberries after UV-C illumination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The levels of flavonoids in blueberries were found to increase after illumination with UV-C. Phytochemicals affected included resveratrol, myricetin 3-arabinoside, quercetin 3-galactoside, quercetin derivative, kaempferol derivative, delphinidin-3-galactoside, cyaniding 3-galactoside, delphinidin 3-...

  13. Study on the structures and illumination characteristics of Chinese ancient oil lamps

    NASA Astrophysics Data System (ADS)

    Zhu, Zhiqiang; Zhan, Qingxuan

    2006-01-01

    Chinese ancient firelight lighting had a long history in which developed technologies were applied. The paper concerns itself with a study of Chinese ancient firelight lighting lamps, including the structures and illuminating characteristics of ancient oil lamps.

  14. Light pipe design method and stepper experimentation for interference effects reduction in laser illumination

    NASA Astrophysics Data System (ADS)

    Poyet, Jean-Michel; Lutz, Yves

    2016-07-01

    The use of light pipes is an efficient and low-cost technique to get a homogeneous illumination for laser-gated viewing systems. However, this technique suffers from drawbacks when used with coherent sources like solid-state lasers. Compacting light pipe-based laser illuminators involves working with small light pipe sections, and experiments show that interference fringes appear on the laser illumination profiles. The principle of light pipe homogenization has been reviewed using geometrical optics to understand the phenomenon better, and a pragmatic light pipe design method, based on laser-gated viewing system parameters, is proposed. Another original solution based on optical stepper is studied to reduce both interference fringes and speckle noise to increase the homogeneity of laser illumination profiles.

  15. Rank-1 accelerated illumination recovery in scanning diffractive imaging by transparency estimation.

    SciTech Connect

    Wu, Hau-Tieng

    2014-08-07

    Illumination retrieval in scanning diffractive imaging a.k.a. ptychography is challenging when the specimen is weakly scattering or surrounded by empty space. We describe a rank-1 acceleration method for weakly scattering or piecewise smooth specimens.

  16. Back-illuminated imager and method for making electrical and optical connections to same

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor)

    2010-01-01

    Methods for bringing or exposing metal pads or traces to the backside of a backside-illuminated imager allow the pads or traces to reside on the illumination side for electrical connection. These methods provide a solution to a key packaging problem for backside thinned imagers. The methods also provide alignment marks for integrating color filters and microlenses to the imager pixels residing on the frontside of the wafer, enabling high performance multispectral and high sensitivity imagers, including those with extremely small pixel pitch. In addition, the methods incorporate a passivation layer for protection of devices against external contamination, and allow interface trap density reduction via thermal annealing. Backside-illuminated imagers with illumination side electrical connections are also disclosed.

  17. Super-resolution two-photon microscopy via scanning patterned illumination

    NASA Astrophysics Data System (ADS)

    Urban, Ben E.; Yi, Ji; Chen, Siyu; Dong, Biqin; Zhu, Yongling; DeVries, Steven H.; Backman, Vadim; Zhang, Hao F.

    2015-04-01

    We developed two-photon scanning patterned illumination microscopy (2P-SPIM) for super-resolution two-photon imaging. Our approach used a traditional two-photon microscopy setup with temporally modulated excitation to create patterned illumination fields. Combing nine different illuminations and structured illumination reconstruction, super-resolution imaging was achieved in two-photon microscopy. Using 2P-SPIM we achieved a lateral resolution of 141 nm, which represents an improvement by a factor of 1.9 over the corresponding diffraction limit. We further demonstrated super-resolution cellular imaging by 2P-SPIM to image actin cytoskeleton in mammalian cells and three-dimensional imaging in highly scattering retinal tissue.

  18. Generation of apodized X-ray illumination and its application to scanning and diffraction microscopy.

    PubMed

    Khakurel, Krishna P; Kimura, Takashi; Nakamori, Hiroki; Goto, Takumi; Matsuyama, Satoshi; Sasaki, Tomoya; Takei, Masashi; Kohmura, Yoshiki; Ishikawa, Tetsuya; Yamauchi, Kazuto; Nishino, Yoshinori

    2017-01-01

    X-ray science has greatly benefited from the progress in X-ray optics. Advances in the design and the manufacturing techniques of X-ray optics are key to the success of various microscopic and spectroscopic techniques practiced today. Here the generation of apodized X-ray illumination using a two-stage deformable Kirkpatrick-Baez mirror system is presented. Such apodized illumination is marked by the suppression of the side-lobe intensities of the focused beam. Thus generated apodized illumination was employed to improve the image quality in scanning X-ray fluorescence microscopy. Imaging of a non-isolated object by coherent X-ray diffractive imaging with apodized illumination in a non-scanning mode is also presented.

  19. The effect of illumination power density on carbon defect configuration in silicon doped GaN

    NASA Astrophysics Data System (ADS)

    Kaess, Felix; Reddy, Pramod; Alden, Dorian; Klump, Andrew; Hernandez-Balderrama, Luis H.; Franke, Alexander; Kirste, Ronny; Hoffmann, Axel; Collazo, Ramón; Sitar, Zlatko

    2016-12-01

    A study of efficacy of point defect reduction via Fermi level control during growth of GaN:Si as a function of above bandgap illumination power density and hence excess minority carrier density is presented. Electrical characterization revealed an almost two-fold increase in carrier concentration and a three-fold increase in mobility by increasing the illumination power density from 0 to 1 W cm-2, corroborating a decrease in compensation and ionic impurity scattering. The effect was further supported by the photoluminescence studies, which showed a monotonic decrease in yellow luminescence (attributed to CN) as a function of illumination power density. Secondary ion mass spectroscopy studies showed no effect of illumination on the total incorporation of Si or C. Thus, it is concluded that Fermi level management changed the configuration of the C impurity as the CN-1 configuration became energetically less favorable due to excess minority carriers.

  20. Reflectance imaging by fiber bundle endoscope: Vertical reconstruction by multipositional illumination

    NASA Astrophysics Data System (ADS)

    Ando, Yoriko; Koida, Kowa; Sawahata, Hirohito; Sakurai, Takashi; Natsume, Mitsuo; Kawano, Takeshi; Numano, Rika

    2016-02-01

    Fiber bundles for imaging internal organs with minimum physical damage have been increasingly developed for both basic life sciences and clinical applications. Reflectance imaging is possible using fiber bundles for detecting the intrinsic optical contrast of blood vessels and tissue structure. The placement of an illumination source adjacent to imaging optics causes scattered light from deeper tissue layers to illuminate superficial tissues and results in a reflectance image. However, it does not have focal capacity and lacks depth resolution. In this study, we performed spatial analysis for the vertical reconstruction of in vivo tissues using a multipositional illumination scheme. The observed image corresponded to the "shadow" of a target object. When we manipulated the location of illumination, the shadow moved horizontally depending on the depth of the target. We used this horizontal displacement as a cue and successfully performed the vertical reconstruction of mouse brain blood vessels.