Results 331 to 340 of about 146,804 (365)
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Medical & Biological Engineering, 1976
The reduction of transmitted light at 650 nm caused by scattering from fibrin polymers as they develop in a clotting plasma sample has proven effective for following the course of the coagulation. An instrument designed on this principle and using entirely solid-state electronics has yielded clotting time reproducible to within ±15%, and has enabled ...
B M Smith, S. I. Reger, O L Updike
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The reduction of transmitted light at 650 nm caused by scattering from fibrin polymers as they develop in a clotting plasma sample has proven effective for following the course of the coagulation. An instrument designed on this principle and using entirely solid-state electronics has yielded clotting time reproducible to within ±15%, and has enabled ...
B M Smith, S. I. Reger, O L Updike
openaire +2 more sources
Analysis of photometric factors based on photometric linearization
Journal of the Optical Society of America A, 2007We propose a method for analyzing photometric factors, such as diffuse reflection, specular reflection, attached shadow, and cast shadow. For analyzing real images, we utilize the photometric linearization method, which was originally proposed for image synthesis.
Yasunori Ishii +2 more
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A Benchmark Dataset and Evaluation for Non-Lambertian and Uncalibrated Photometric Stereo
IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019Classic photometric stereo is often extended to deal with real-world materials and work with unknown lighting conditions for practicability. To quantitatively evaluate non-Lambertian and uncalibrated photometric stereo, a photometric stereo image dataset
Boxin Shi +5 more
semanticscholar +1 more source
EKLT: Asynchronous Photometric Feature Tracking Using Events and Frames
International Journal of Computer Vision, 2018We present EKLT, a feature tracking method that leverages the complementarity of event cameras and standard cameras to track visual features with high temporal resolution. Event cameras are novel sensors that output pixel-level brightness changes, called
Daniel Gehrig +3 more
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CNN-PS: CNN-based Photometric Stereo for General Non-Convex Surfaces
European Conference on Computer Vision, 2018Most conventional photometric stereo algorithms inversely solve a BRDF-based image formation model. However, the actual imaging process is often far more complex due to the global light transport on the non-convex surfaces.
Satoshi Ikehata
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Photometric Concepts and Magnitudes [PDF]
, 1987 Most astronomical observations utilize electromagnetic radiation in one way or another. We can obtain information on the physical nature of a radiation source by studying the energy distribution of its radiation. We shall now introduce some basic concepts characterizing electromagnetic radiation.
Pekka Kröger +4 more
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PHOTOMETRIC AND IMAGING PERFORMANCE [PDF]
EAS Publications Series, 2002 Three topics within GAIA photometry have been selected for discussion here. (1) The sampling scheme of the CCDs has been tuned to serve the various purposes: detection of stars, astrometry, broad- and medium-band photometry, and imaging of a small area around each detected star, but the tuning may not yet be optimal.
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PS-FCN: A Flexible Learning Framework for Photometric Stereo
European Conference on Computer Vision, 2018This paper addresses the problem of photometric stereo for non-Lambertian surfaces. Existing approaches often adopt simplified reflectance models to make the problem more tractable, but this greatly hinders their applications on real-world objects.
Guanying Chen +2 more
semanticscholar +1 more source
Photometric method for determining surface orientation from multiple images
, 1980A novel technique called photometric stereo is introduced. The idea of photometric stereo is to vary the direction of incident illumination between successive images, while holding the viewing direction constant. It is shown that this provides sufficient
R. Woodham
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IEEE Transactions on Pattern Analysis and Machine Intelligence, 2008
Conventional photometric stereo recovers one normal direction per pixel of the input image. This fundamentally limits the scale of recovered geometry to the resolution of the input image, and cannot model surfaces with subpixel geometric structures. In this paper, we propose a method to recover subpixel surface geometry by studying the relationship ...
Tan, Ping, Lin, Stephen, Quan, Long
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Conventional photometric stereo recovers one normal direction per pixel of the input image. This fundamentally limits the scale of recovered geometry to the resolution of the input image, and cannot model surfaces with subpixel geometric structures. In this paper, we propose a method to recover subpixel surface geometry by studying the relationship ...
Tan, Ping, Lin, Stephen, Quan, Long
openaire +4 more sources