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OPTICS CONTINUUM 2022年第4期1卷 834-845页

作者： Aslani, Valese Guerra, Flavio Steinitz, Adriana Wilhelm, Philipp Haist, Tobias Univ Stuttgart Inst Tech Opt Pfaffenwaldring 9 D-70569 Stuttgart Germany

We introduce an optical and a digital averaging technique that considerably improves edge localization performance. Especially for high quality images, the optical method achieves measurement uncertainties down to levels of millipixels. The approach uses an optical replication scheme based on a computer-generated hologram to reduce noise and discretization errors. The second method is based on a neural network denoising architecture and is especially suited for high levels of photon noise. Edge localization can be improved by up to 60% while preserving high lateral and temporal resolution. The methods are first tested using high quality images obtained by a scientific CMOS sensor imaging a razor blade mounted on a mechanical stage. Then, the laboratory results are tested for larger distances to validate the methods for building deformation measurements.

关键词： Digital micromirror devices image processing image processing algorithms image sensors Medical image processing Temporal resolution

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ASSOCIATIVE NETWORK APPLICATIONS TO LOW-LEVEL MACHINE VISION

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APPLIED OPTICS 1987年第10期26卷 1919-1926页

作者： OYSTER, JM VICUNA, F BROADWELL, W IBM LOS ANGELES SCI CTR LOS ANGELES CA 90025 USA

This paper explores the application of a parallel computational model, the associative network, to problems in low-level machine vision. A formal description of the associative network model is presented. Then associative networks are designed for performing Boolean functions, edge detection, and the Hough transform. Associative networks feature very flexible processor interconnections. The flexible processor interconnections allow for parallelism in the algorithm design beyond what is feasible in other parallel computational models. This work demonstrates that image processing transformations, often too slow to be practical on a sequential machine, can be executed rapidly with associative networks.

关键词： Computer simulation Edge detection image processing image processing algorithms Machine vision Pattern recognition

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OBJECTIVE ASSESSMENT OF image QUALITY - EFFECTS OF QUANTUM NOISE AND OBJECT VARIABILITY

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS image SCIENCE AND VISION 1990年第7期7卷 1266-1278页

作者： BARRETT, HH UNIV ARIZONA DEPT RADIOLTUCSONAZ 85721

A number of task-specific approaches to the assessment of image quality are treated. Both estimation and classification tasks are considered, but only linear estimators or classifiers are permitted. Performance on these tasks is limited by both quantum noise and object variability, and the effects of postprocessing or image-reconstruction algorithms are explicitly included. The results are expressed as signal-to-noise ratios (SNR’s). The interrelationships among these SNR’s are considered, and an SNR for a classification task is expressed as the SNR for a related estimation task times four factors. These factors show the effects of signal size and contrast, conspicuity of the signal, bias in the estimation task, and noise correlation. Ways of choosing and calculating appropriate SNR’s for system evaluation and optimization are also discussed.

关键词： image processing image processing algorithms image quality image reconstruction Matched filtering Medical imaging

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Wavemeter based on dispersion and speckle in a tapered hollow waveguide

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OSA CONTINUUM 2019年第2期2卷 495-506页

作者： Hornig, G. J. Harrison, T. R. Bu, L. Azmayesh-Fard, S. Decorby, R. G. Univ Alberta ECE Dept 9211-116 St Edmonton AB T6G 1H9 Canada

We demonstrate a broadband wavemeter by imaging the radiation from multiple interfering modes approaching cutoff in a tapered hollow waveguide (clad by omnidirectional Bragg mirrors). Dispersion of the cutoff point was used to extract a coarse wavelength estimate, and subsequent computational analysis of the complex standing wave radiation pattern leading up to the cutoff point enabled a much finer estimate. This approach leverages the principles of speckle-based spectrometers but with added functionality provided by the spectral-spatial dispersion of the mode cutoff position. In proof-of-principle work, we verified a resolution < 10 pm over an operating range of nearly 100 nm in the near infrared using a tapered waveguide with a length < 1 mm. Significantly enhanced resolution should be possible through feasible refinements of the waveguides and peripheral components. (c) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Hollow waveguides image processing algorithms image sensors Near infrared radiation Optical devices Speckle patterns

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MULTIRESOLUTION, ERROR-CONVERGENCE HALF-TONE ALGORITHM

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS image SCIENCE AND VISION 1991年第4期8卷 625-636页

作者： PELI, E TUFTS UNIV SCH MEDMEDFORDMA 02155

A new halftone algorithm is described. The algorithm is designed for implementation on a parallel architecture in order to provide fast, progressive coding of moderate-resolution images. The design is based on a multiresolution, hierarchical, pyramidal structure. At each pyramid level, the binarized image is compared with the original, graytone image over a successively larger window of pixels for calculation of a weighted averaged error. Within each level, selected binarized pixels are tested for possible changes in the binary assignment. The binary assignment is changed if the change results in a lower average error over the entire window. Varying the selection of test pixels can cause the same process to provide clustered-dot patterns and dithering. A comparison of performance with the best implementation of the error-propagation algorithm is presented visually. Quality is compared also in terms of isotropy of the texture and the appropriate blue-noise characteristics in areas of uniform gray tone. The benefits of this algorithm are realized with moderate-resolution display of the order of 512 dots x 512 dots. The processing can be carried out on smaller blocks since the results can be combined without any visible seams or edge effects.

关键词： image processing algorithms image quality image sharpening Spatial frequency Spatial resolution Visual system

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ULTRAHIGH RESOLUTION SANDWICH HOLOGRAPHY

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APPLIED OPTICS 1984年第10期23卷 1474-1480页

作者： DZUBUR, A VUKICEVIC, D INST FIZIKU SVEUCILISTA Zagreb YUGOSLAVIA

A modified method of fabrication of sandwich holographic interferograms coupled with a digital evaluation technique has yielded ultrahigh resolution of surface deformation. The computer processing technique permits both the subfringe resolution and automatic fringe order determination (i.e., discrimination between depression and elevation of the deformed object surface). The technique presented here requires neither the interactive processing nor the fringe interpolation required by other techniques. Such processes are inaccurate, especially when there is a small number of interference fringes. With this type of analysis, sandwich interferometry is capable of fast, simple, ultrahigh resolution of surface deformation.

关键词： Digital image processing Discrete Fourier transforms Fringe analysis Holographic interferometry image processing algorithms Spatial frequency

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TRANSFORMING imageS INTO BLOCK STATIONARY BEHAVIOR

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APPLIED OPTICS 1983年第10期22卷 1462-1473页

作者： STRICKLAND, RN []The author is with University of Arizona Electrical Engineering Department Tucson Arizona 85721.

The statistical behavior of images is inherently nonstationary. Unfortunately, most image processing algorithms assume stationary image models. Spatially adaptive algorithms have been developed which take into account local image statistics. In this paper we derive radiometric and geometric transforms which generate nearly stationary (block stationary) images in the first and second moments. We show that true stationarity is impossible to realize. The aim of these transformations is to enhance the performance of nonadaptive processing techniques, in particular data compression.

关键词： Digital image processing image processing image processing algorithms image restoration Point spread function Power spectra

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Efficient sub-pixel convolutional neural network for terahertz image super-resolution

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OPTICS LETTERS 2022年第12期47卷 3115-3118页

作者： Ruan, Haihang Tan, Zhiyong Chen, Liangtao Wan, Wenjain Cao, Juncheng Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Lab Terahertz Solid State Technol Shanghai 200050 Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Beijing 100049 Peoples R China Shanghai Tech Univ Sch Informat Sci & Technol Shanghai 201203 Peoples R China

Terahertz waves are electromagnetic waves located at 0.1-10 THz, and terahertz imaging technology can be applied to security inspection, biomedicine, non-destructive testing of materials, and other fields. At present, terahertz images have unclear data and rough edges. Therefore, improving the resolution of terahertz images is one of the current hot research topics. This paper proposes an efficient terahertz image super-resolution model, which is used to extract low-resolution (LR) image features and learn the mapping of LR images to high-resolution (HR) images, and then introduce an attention mechanism to let the network pay attention to more information features. Finally, we use sub-pixel convolution to learn a set of scaling filters to upgrade the final LR feature map to an HR output, which not only reduces the model complexity, but also improves the quality of the terahertz image. The resolution reaches 31.67 db on the peak signal-to-noise ratio (PSNR) index and 0.86 on the structural similarity (SSIM) index. Experiments show that the efficient sub-pixel convolutional neural network used in this article achieves better accuracy and visual improvement compared with other terahertz image super-resolution algorithms. (C) 2022 Optica Publishing Group .

关键词： image processing image processing algorithms image quality Nondestructive testing Optical imaging Terahertz imaging

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Capillary red blood cell velocimetry by phase-resolved optical coherence tomography

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OPTICS LETTERS 2017年第19期42卷 3976-3979页

作者： Tang, Jianbo Erdener, Sefik Evren Fu, Buyin Boas, David A. Harvard Med Sch Massachusetts Gen Hosp Athinoula A Martinos Ctr Biomed Imaging Charlestown MA 02129 USA Boston Univ Dept Biomed Engn Neurophoton Ctr Boston MA 02215 USA

We present a phase-resolved optical coherence tomography (OCT) method to extend Doppler OCT for the accurate measurement of the red blood cell (RBC) velocity in cerebral capillaries. OCT data were acquired with an M-mode scanning strategy (repeated A-scans) to account for the single-file passage of RBCs in a capillary, which were then high-pass filtered to remove the stationary component of the signal to ensure an accurate measurement of phase shift of flowing RBCs. The angular frequency of the signal from flowing RBCs was then quantified from the dynamic component of the signal and used to calculate the axial speed of flowing RBCs in capillaries. We validated our measurement by RBC passage velocimetry using the signal magnitude of the same OCT time series data. (C) 2017 Optical Society of America

关键词： Dynamic light scattering image processing algorithms image quality Phase measurement Phase shift Three dimensional imaging

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Type-II superlattice dual-band LWIR imager with M-barrier and Fabry-Perot resonance

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OPTICS LETTERS 2011年第13期36卷 2560-2562页

作者： Huang, Edward Kwei-wei Haddadi, Abbas Chen, Guanxi Binh-Minh Nguyen Minh-Anh Hoang McClintock, Ryan Stegall, Mark Razeghi, Manijeh Northwestern Univ Dept Elect Engn & Comp Sci Evanston IL 60208 USA SE IR Corp Goleta CA 93117 USA

We report a high performance long-wavelength IR dual-band imager based on type-II superlattices with 100% cutoff wavelengths at 9: 5 mu m (blue channel) and 13 mu m (red channel). Test pixels reveal background-limited behavior with specific detectivities as high as similar to 5 x 10(11) Jones at 7: 9 mu m in the blue channel and similar to 1 x 10(11) Jones at 10: 2 mu m in the red channel at 77 K. These performances were attributed to low dark currents thanks to the M-barrier and Fabry-Perot enhanced quantum efficiencies despite using thin 2 mu m absorbing regions. In the imager, the high signal-to-noise ratio contributed to median noise equivalent temperature differences of similar to 20 milli-Kelvin for both channels with integration times on the order of 0.5 ms, making it suitable for high speed applications. (C) 2011 Optical Society of America

关键词： image processing algorithms Multispectral imaging Optical superlattices Physical vapor deposition Quantum efficiency Refractive index

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