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Computational Optical Sensing and Imaging, COSI 2012

作者： Bovik, Alan C. University of Texas at Austin United States

ISBN: (纸本)1557529477

Blind image Quality Assessment (Blind IQA) is usually synonymous with “no-reference” IQA, viz., without a pristine image available for quality comparison. However, other sources of information are used to design IQA models: human opinion scores, mathematical models of distortion, perceptual models; statistical models of distorted images, and statistical models of images that are not distorted.

关键词： algorithms Distortion image processing image processing algorithms image quality assessment

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Sensor noise informed representation of hyperspectral data, with benefits for image storage and processing

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OPTICS EXPRESS 2011年第14期19卷 13031-13046页

作者： Skauli, Torbjorn Norwegian Def Res Estab FFI N-2027 Kjeller Norway

Many types of hyperspectral image processing can benefit from knowledge of noise levels in the data, which can be derived from sensor physics. Surprisingly, such information is rarely provided or exploited. Usually, the image data are represented as radiance values, but this representation can lead to suboptimal results, for example in spectral difference metrics. Also, radiance data do not provide an appropriate baseline for calculation of image compression ratios. This paper defines two alternative representations of hyperspectral image data, aiming to make sensor noise accessible to image processing. A "corrected raw data" representation is proportional to the photoelectron count and can be processed like radiance data, while also offering simpler estimation of noise and somewhat more compact storage. A variance-stabilized representation is obtained by square-root transformation of the photodetector signal to make the noise signal-independent and constant across all bands while also reducing data volume by almost a factor 2. Then the data size is comparable to the fundamental information capacity of the sensor, giving a more appropriate measure of uncompressed data size. It is noted that the variance-stabilized representation has parallels in other fields of imaging. The alternative data representations provide an opportunity to reformulate hyperspectral processing algorithms to take actual sensor noise into account. (C) 2011 Optical Society of America

关键词： Cathode ray tubes Hyperspectral image processing Hyperspectral imaging image compression image processing image processing algorithms

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Digital camera simulation

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APPLIED OPTICS 2012年第4期51卷 A80-A90页

作者： Farrell, Joyce E. Catrysse, Peter B. Wandell, Brian A. Stanford Univ Dept Elect Engn Stanford CA 94305 USA Stanford Univ Edward L Ginzton Lab Stanford CA 94305 USA Stanford Univ Dept Psychol Stanford CA 94305 USA

We describe a simulation of the complete image processing pipeline of a digital camera, beginning with a radiometric description of the scene captured by the camera and ending with a radiometric description of the image rendered on a display. We show that there is a good correspondence between measured and simulated sensor performance. Through the use of simulation, we can quantify the effects of individual digital camera components on system performance and image quality. This computational approach can be helpful for both camera design and image quality assessment. (C) 2012 Optical Society of America

关键词： Digital image processing image processing image processing algorithms image quality image quality assessment Sensor performance

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Real-time concealed-object detection and recognition with passive millimeter wave imaging

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OPTICS EXPRESS 2012年第9期20卷 9371-81页

作者： Yeom, Seokwon Lee, Dong-Su Jang, YuShin Lee, Mun-Kyo Jung, Sang-Won Daegu Univ Div Comp & Commun Engn Gyongsan 712714 Gyeongbuk South Korea Samsung Thales Yongin 449885 South Korea

Millimeter wave (MMW) imaging is finding rapid adoption in security applications such as concealed object detection under clothing. A passive MMW imaging system can operate as a stand-off type sensor that scans people in both indoors and outdoors. However, the imaging system often suffers from the diffraction limit and the low signal level. Therefore, suitable intelligent image processing algorithms would be required for automatic detection and recognition of the concealed objects. This paper proposes real-time outdoor concealed-object detection and recognition with a radiometric imaging system. The concealed object region is extracted by the multi-level segmentation. A novel approach is proposed to measure similarity between two binary images. Principal component analysis (PCA) regularizes the shape in terms of translation and rotation. A geometric-based feature vector is composed of shape descriptors, which can achieve scale and orientation-invariant and distortion-tolerant property. Class is decided by minimum Euclidean distance between normalized feature vectors. Experiments confirm that the proposed methods provide fast and reliable recognition of the concealed object carried by a moving human subject. (C) 2012 Optical Society of America

关键词： Diffraction limit image processing algorithms image quality Millimeter wave imaging Millimeter waves Object detection

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Accuracy of the reconstruction of the crystalline lens gradient index with optimization methods from Ray Tracing and Optical Coherence Tomography data

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OPTICS EXPRESS 2011年第20期19卷 19265-19279页

作者： de Castro, Alberto Barbero, Sergio Ortiz, Sergio Marcos, Susana CSIC Inst Opt Daza de Valdes Madrid 28006 Spain

The accuracy of the reconstruction of the Gradient Refractive Index (GRIN) of the crystalline lens from optimization methods was evaluated. Different input data, including direction cosines of deflected rays, ray impacts obtained from ray tracing and optical path differences from Optical Coherence Tomography (OCT) were studied. Three different GRIN models were analyzed. The experimental errors of the different experimental input data were estimated from comparisons of measurements and simulations using artificial lenses of known geometries. The experimental errors in the surfaces shape measurement and the influence of the number of rays were also considered. OCT-based input data produced the most accurate GRIN reconstructions. We found that optimization methods (combining global and local search algorithms) allow GRIN reconstructions with acceptable accuracies for moderate noise level. (C) 2011 Optical Society of America

关键词： Crystalline lens Fiber optic sensors image processing algorithms Magnetic resonance imaging Ray tracing Refractive index

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Diffusion dynamics of small molecules from mesoporous silicon films by real-time optical interferometry

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APPLIED OPTICS 2011年第27期50卷 5329-5337页

作者： Mares, Jeremy W. Weiss, Sharon M. Vanderbilt Univ Dept Elect Engn & Comp Sci Nashville TN 37235 USA

Time-dependent laser reflectometry measurements are presented as a means to rigorously characterize analyte diffusion dynamics of small molecules from mesoporous silicon (PSi) films for drug delivery and membrane physics applications. Calculations based on inclusion of a spatially and temporally dependent solute concentration profile in a one-dimensional Fickian diffusion flow model are performed to determine the diffusion coefficients for the selected prototypical polar species, sucrose (340 Da), exiting from PSi films. The diffusion properties of the molecules depend on both PSi pore size and film thickness. For films with average pore diameters between 10-30 nm and film thicknesses between 300-900 nm, the sucrose diffusion coefficient can be tuned between approximately 100 and 550 mu m(2)/s. Extensions of the real-time measurement and modeling approach for determining the diffusivity of small molecules that strongly interact with and corrode the internal surfaces of PSi films are also discussed. (C) 2011 Optical Society of America

关键词： Beam scattering Diffusion Effective refractive index image processing algorithms Laser interferometry Scanning electron microscopy

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Visibility-enhanced reconstruction of three-dimensional objects under a heavily scattering medium through combined use of intermediate view reconstruction, multipixel extraction, and histogram equalization methods in the conventional integral imaging system

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APPLIED OPTICS 2011年第28期50卷 5369-5381页

作者： Zhang, Miao Piao, Yongri Kim, Eun-Soo Kwangwoon Univ Dept Elect Engn Display Res Ctr 3D Seoul 139701 South Korea

In this paper, we propose an effective approach for reconstructing visibility-enhanced three-dimensional (3D) objects under the heavily scattering medium of dense fog in the conventional integral imaging system through the combined use of the intermediate view reconstruction (IVR), multipixel extraction (MPE), and histogram equalization (HE) methods. In the proposed system, the limited number of elemental images (EIs) picked up from the 3D objects under the dense fog is increased by as many as required by using the IVR technique. The increased number of EIs is transformed into the sub-images (SIs) in which the resolution of the transformed SIs has been also improved as much as possible with the MPE method. Subsequently, by using the HE algorithm, the histogram of the resolution-enhanced SIs is uniformly redistributed over the entire range of discrete pixel levels of the image in a way that the subimage contrast can be much enhanced. Then, these equalized SIs are converted back into the newly modified EIs, and consequently a visibility-enhanced 3D object image can be reconstructed. Successful experimental results with the test object confirmed the feasibility of the proposed method. (C) 2011 Optical Society of America

关键词： image processing image processing algorithms image quality Imaging techniques Optical devices Three dimensional imaging

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Spatially selective photonic crystal enhanced fluorescence and application to background reduction for biomolecule detection assays

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OPTICS EXPRESS 2011年第23期19卷 23327-23340页

作者： Chaudhery, Vikram Huang, Cheng-Sheng Pokhriyal, Anusha Polans, James Cunningham, Brian T. Univ Illinois Dept Elect & Comp Engn Urbana IL 61801 USA Univ Illinois Dept Phys Urbana IL 61801 USA Univ Illinois Dept Bioengn Urbana IL 61801 USA

By combining photonic crystal label-free biosensor imaging with photonic crystal enhanced fluorescence, it is possible to selectively enhance the fluorescence emission from regions of the PC surface based upon the density of immobilized capture molecules. A label-free image of the capture molecules enables determination of optimal coupling conditions of the laser used for fluorescence imaging of the photonic crystal surface on a pixel-by-pixel basis, allowing maximization of fluorescence enhancement factor from regions incorporating a biomolecule capture spot and minimization of background autofluorescence from areas between capture spots. This capability significantly improves the contrast of enhanced fluorescent images, and when applied to an antibody protein microarray, provides a substantial advantage over conventional fluorescence microscopy. Using the new approach, we demonstrate detection limits as low as 0.97 pg/ml for a representative protein biomarker in buffer. (C) 2011 Optical Society of America

关键词： Electric fields Fluorescence microscopy image processing image processing algorithms Laser beams Photonic crystals

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Combined two-photon microscopy and optical coherence tomography using individually optimized sources

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OPTICS EXPRESS 2011年第14期19卷 13089-13096页

作者： Jeong, Bosu Lee, Byunghak Jang, Min Seong Nam, Hyoseok Yoon, Sang June Wang, Taejun Doh, Junsang Yang, Bo-Gie Jang, Myoung Ho Kim, Ki Hean Pohang Univ Sci & Technol Sch Interdisciplinary Biosci & Bioengn Pohang 790784 Gyeongbuk South Korea Pohang Univ Sci & Technol Dept Mech Engn Pohang 790784 Gyeongbuk South Korea Pohang Univ Sci & Technol Div Integrat Biosci & Biotechnol Pohang 790784 Gyeongbuk South Korea Osaka Univ Lab Gastrointestinal Immunol WPI Immunol Frontier Res Ctr Suita Osaka 5650871 Japan

The combination of two-photon microscopy (TPM) and optical coherence tomography (OCT) is useful in conducting in-vivo tissue studies, because they provide complementary information regarding tissues. In the present study, we developed a new combined system using separate light sources and scanners for individually optimal imaging conditions. TPM used a Ti-Sapphire laser and provided molecular and cellular information in microscopic tissue regions. Meanwhile, OCT used a wavelength-swept source centered at 1300 nm and provided structural information in larger tissue regions than TPM. The system was designed to do simultaneous imaging by combining light from both sources. TPM and OCT had the field of view values of 300 mu m and 800 mu m on one side respectively with a 20x objective. TPM had resolutions of 0.47 mu m and 2.5 mu m in the lateral and axial directions respectively, and an imaging speed of 40 frames/s. OCT had resolutions of 5 mu m and 8 mu m in lateral and axial directions respectively, a sensitivity of 97dB, and an imaging speed of 0.8 volumes per second. This combined system was tested with simple microsphere specimens, and was then applied to image small intestine and ear tissues of mouse models ex-vivo. Molecular, cellular, and structural information of the tissues were visualized using the proposed combined system. (C) 2011 Optical Society of America

关键词： Adaptive optics image processing algorithms In vivo imaging Nonlinear photonic crystals Photonic crystal fibers Second harmonic generation

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Spectrally encoded spectral imaging

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OPTICS EXPRESS 2011年第7期19卷 6913-6922页

作者： Abramov, Avraham Minai, Limor Yelin, Dvir Technion Israel Inst Technol Dept Biomed Engn IL-32000 Technion Haifa Israel

Spectral imaging, i.e. the acquisition of the spectrum emitted from each sample location, is a powerful tool for a wide variety of applications in science and technology. For biomedical applications, spectral imaging is important for accurate analysis of a biological specimen and for assisting clinical diagnosis, however it could be challenging mainly due to the typically low damage thresholds and strict time constraints. Here, we present a fiber-based technique termed spectrally encoded spectral imaging (SESI), in which a fully emitted spectrum is captured from each resolvable point of a specimen using an additional lateral scanning of the spectrally encoded line. The technique is demonstrated by capturing spectral data cubes of a color print and of a green leaf, and its potential advantage in signal-to-noise ratio is theoretically discussed. Using a miniaturized gratinglens configuration, SESI could be conducted endoscopically, allowing minimally invasive color and spectral imaging in remote locations of the body. (C)2011 Optical Society of America

关键词： Hyperspectral imaging image processing algorithms Imaging systems Imaging techniques Multispectral imaging Spectral imaging

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