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International Conference on Optical Instruments and Technology - Optoelectronic Measurement Technology and Systems

作者： Ma, Suodong Wang, Yan Pan, Qiao Shen, Weimin Soochow Univ Coll Phys Optoelect & Energy Suzhou 215006 Peoples R China Soochow Univ Key Lab Adv Opt Mfg Technol Jiangsu Prov Minist China Suzhou 215006 Peoples R China Soochow Univ Key Lab Modern Opt Technol Educ Minist China Suzhou 215006 Peoples R China

ISBN: (纸本)9781628417999

Owing to the ability of generating designated spectrums as special requirements, spectrum-controllable light source has attracted huge interesting in several fields, e.g. medical science, industrial detection, defense-related testing. In principle, optical performance of a spectrum-controllable light source can be predicted by some transfer functions of the corresponding system, e.g. modulation transfer function (MTF). Unfortunately, the aforementioned research work is still lacking at present although it is meaningful for the optical design and evaluation of this new kind of light sources. Hence, a MTF model for a modified version of our previously-proposed spectrum-controllable light source system based on a Digital Micromirror Device (DMD) and an Offner dispersion configuration with a convex grating is deduced as an example. Related preliminary analyses have been present in this paper as well.

关键词： Light source Spectrum-controllable modulation transfer function Offner dispersion DMD

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Accuracy and uncertainty in random speckle modulation transfer function measurement of infrared focal plane arrays

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OPTICAL ENGINEERING 2016年第12期55卷 121729-121729页

作者： Barnard, Kenneth J. Jacobs, Eddie L. Plummer, Philip J. Air Force Res Lab RYMT 2241 Avion Circle Wright Patterson AFB OH 45433 USA Univ Memphis Dept Elect & Comp Engn 109 Engn Technol Bldg Memphis TN 38152 USA

This paper expands upon a previously reported random speckle technique for measuring the modulation transfer function of midwave infrared focal plane arrays by considering a number of factors that impact the accuracy of the estimated modulation transfer function. These factors arise from assumptions in the theoretical derivation and bias in the estimation procedure. Each factor is examined and guidelines are determined to maintain accuracy within 2% of the true value. The uncertainty of the measurement is found by applying a one-factor ANOVA analysis and confidence intervals are established for the results. The small magnitude of the confidence intervals indicates a very robust technique capable of distinguishing differences in modulation transfer function among focal plane arrays on the order of a few percent. This analysis directly indicates the high quality of the random speckle modulation transfer function measurement technique. The methodology is applied to a focal plane array and results are presented that emphasize the need for generating independent random speckle realizations to accurately assess measured values. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： speckle focal plane array modulation transfer function power spectral density midwave infrared confidence intervals ANOVA

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Measuring the modulation-transfer function of radiation-tolerant machine-vision system using the sum of harmonic components of different frequency

Measuring the modulation-transfer function of radiation-tole...

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Conference on Optical Sensors

作者： Perezyabov, Oleg. A. Maltseva, Nadezhda K. Ilinski, Aleksandr V. ITMO Univ 49 Kronverksky Pr St Petersburg 197101 Russia SI Vavilov State Opt Inst 12 Birzhevaya Liniya St Petersburg 199034 Russia

ISBN: (数字)9781510609648

ISBN: (纸本)9781510609631;9781510609648

There are a number of robotic systems that are used for nuclear power plant maintenance and it is important to ensure the necessary safety level. The machine-vision systems are applied for this purpose. There are special requirements for the image quality of these systems. To estimate the resolution of a video-system one should determine the impact of the system on the special test pattern. In this paper we describe the procedure of determining the number of the modulation transfer function values of the radiation-tolerant machine-vision systems using the test pattern, containing the sum of the harmonic functions of different frequency.

关键词： modulation transfer function harmonic function radiation-tolerant system machine vision test-pattern

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A new modulation transfer function for ocean wave spectra retrieval from X-band marine radar imagery

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Chinese Journal of Oceanology and Limnology 2015年第5期33卷 1132-1141页

作者：陈忠彪张彪何宜军丘仲锋 PERRIE William Nanjing University of Information Science and Technology Bedford Institute of Oceanography

When imaging ocean surface waves by X-band marine radar, the radar backscatter from the sea surface is modulated by the long surface gravity waves. The modulation transfer function （MTF） comprises tilt, hydrodynamic, and shadowing modulations. A conventional linear MTF was derived using HH-polarized radar observations under conditions of deep water. In this study, we propose a new quadratic polynomial MTF based on W-polarized radar measurements taken from heterogeneous nearshore wave fields. This new MTF is obtained using a radar-observed image spectrum and in situ buoy-measured wave frequency spectrum. We validate the MTF by comparing peak and mean wave periods retrieved from X-band marine radar image sequences with those measured by the buoy. It is shown that the retrieval accuracies of peak and mean wave periods of the new MTF are better than the conventional MTF. The results also show that the bias and root mean square errors of the peak and mean wave periods of the new MTF are 0.05 and 0.88 s, and 0.32 and 0.53 s, respectively, while those of the conventional MTF are 0.61 and 0.98 s, and 1.39 and 1.48 s, respectively. Moreover, it is also shown that the retrieval results are insensitive to the coefficients in the proposed MTF.

关键词： X-band marine radar modulation transfer function ocean wave spectra

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Optimized square-root phase mask to generate defocus-invariant modulation transfer function in hybrid imaging systems

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OPTICAL ENGINEERING 2015年第3期54卷 1-7页

作者： Van Nhu Le Fan, Zhigang Nghia Pham Minh Chen, Shouqian Harbin Inst Technol Sch Astronaut Harbin 150001 Peoples R China Harbin Inst Technol Sch Elect & Informat Engn Harbin 150001 Peoples R China

Wavefront coding involves the use of an asymmetrical phase mask to extend the depth of field of incoherent imaging systems. The performance of wavefront coding systems depends on designing a suitable phase profile to generate the defocus-invariant imaging characteristic. We proposed a square-root phase mask with two profile factors for achieving a steadier defocused modulation transfer function (MTF). Several evaluation methods are employed for the purpose of performance comparison between the proposed phase mask and the previously suggested phase masks under the constraint condition that the phase parameters are optimized at the same level of noise gain. Numerical results show that the square-root phase mask yields better properties in extended depth of field imaging, especially in acquiring defocus-invariant MTFs and eliminating image artifacts associated with the decoded images. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： extended depth of field wavefront coding phase mask modulation transfer function defocus

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Measurement of the modulation transfer function of an X-ray microscope based on multiple Fourier orders analysis of a Siemens star

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OPTICS EXPRESS 2015年第8期23卷 9567-9572页

作者： Oton, Joaquin Sorzano, Carlos Oscar S. Marabini, Roberto Pereiro, Eva Carazo, Jose M. CSIC Natl Biotechnol Ctr Biocomp Unit Madrid 28049 Spain Univ Autonoma Madrid Escuela Politecn Super E-28049 Madrid Spain ALBA Synchrotron Light Source Barcelona 08290 Spain

Soft X-ray tomography (SXT) is becoming a powerful imaging technique to analyze eukaryotic whole cells close to their native state. Central to the analysis of the quality of SXT 3D reconstruction is the estimation of the spatial resolution and Depth of Field of the X-ray microscope. In turn, the characterization of the modulation transfer function (MTF) of the optical system is key to calculate both parameters. Consequently, in this work we introduce a fully automated technique to accurately estimate the transfer function of such an optical system. Our proposal is based on the preprocessing of the experimental images to obtain an estimate of the input pattern, followed by the analysis in Fourier space of multiple orders of a Siemens Star test sample, extending in this way its measured frequency range. (C) 2015 Optical Society of America

关键词： Image processing modulation transfer function Soft x rays Spatial resolution Three dimensional reconstruction X ray microscopy

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Resolution enhancement in active underwater polarization imaging with modulation transfer function analysis

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APPLIED OPTICS 2015年第11期54卷 3294-3302页

作者： Han, Jiefei Yang, Kecheng Xia, Min Sun, Liying Cheng, Zao Liu, Hao Ye, Junwei Huazhong Univ Sci & Technol Sch Opt & Elect Informat Wuhan 430074 Peoples R China

Active polarization imaging technology is a convenient and promising method for imaging in a scattering medium such as fog and turbid water. However, few studies have investigated the influence of polarization on the resolution in underwater imaging. This paper reports on the effects of polarization detection on the resolution of underwater imaging by using active polarization imaging technology. An experimental system is designed to determine the influence under various polarization and water conditions. The modulation transfer function is introduced to estimate the resolution variations at different spatial frequencies. Results show that orthogonal detection supplies the best resolution compared with other polarization directions in the turbid water. The performance of the circular polarization method is better than the linear process. However, if the light propagates under low scattering conditions, such as imaging in clean water or at small optical thickness, the resolution enhancement is not sensitive to the polarization angles. (C) 2015 Optical Society of America

关键词： modulation transfer function Imaging through turbid media Polarimetric imaging

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Quantification of Optical Clarity of Transparent Soil Using the modulation transfer function

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GEOTECHNICAL TESTING JOURNAL 2015年第5期38卷 588-602页

作者： Black, Jonathan A. Take, W. Andy Univ Sheffield Dept Civil & Struct Engn Sheffield S1 3JD S Yorkshire England Queens Univ Dept Civil Engn Kingston ON K7L 3N6 Canada

Transparent synthetic soils have been developed as a soil surrogate to enable internal visualization of geotechnical processes in physical models. Transparency of the soil dictates the overarching success of the technique;however, despite this fundamental requirement, no quantitative framework has yet been established to appraise the visual quality of transparent soil. Previous approaches to assess and optimize transparency quality included an eye chart assessment method, although this approach is highly subjective and operator-dependent. In this paper, an independent method for quantitatively assessing the optical quality of transparent soil is proposed based on the optical calibration method, modulation transfer function (MTF). The work explores this hypothesis and assesses the potential for MTF to quantify the optical quality of transparent soils for a number of aspects including (i) optimum oil blend ratio, (ii) depth of viewing plane, and (iii) temperature. The results confirmed that MTF offers a robust and reliable method to provide an independent quantitative measure of the optical quality of transparent soil. The impact of reduced soil transparency and the ability to track speckle patterns-thus accuracy and precision of displacement measurement-was correlated with MTF to evaluate the permissible viewing depth of transparent soil.

关键词： transparent soil modulation transfer function transparency physical modeling

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Addressing challenges of modulation transfer function measurement with fisheye lens cameras

Addressing challenges of modulation transfer function measur...

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Conference on Image Sensors and Imaging Systems

作者： Deegan, Brian M. Denny, Patrick E. Zlokolica, Vladimir Dever, Barry Russell, Laura Vale Vis Syst Galway *** Ireland Univ Novi Sad Fac Tech Sci Novi Sad 21000 Serbia

ISBN: (纸本)9781628414936

modulation transfer function (MTF) is a well defined and accepted method of measuring image sharpness. The slanted edge test, as defined in ISO12233 is a standard method of calculating MTF, and is widely used for lens alignment and auto-focus algorithm verification. However, there are a number of challenges which should be considered when measuring MTF in cameras with fisheye lenses. Due to trade-offs related Petzval curvature, planarity of the optical plane is difficult to achieve in fisheye lenses. It is therefore critical to have the ability to accurately measure sharpness throughout the entire image, particularly for lens alignment. One challenge for fisheye lenses is that, because of the radial distortion, the slanted edges will have different angles, depending on the location within the image and on the distortion profile of the lens. Previous work in the literature indicates that MTF measurements are robust for angles between 2 and 10 degrees. Outside of this range, MTF measurements become unreliable. Also, the slanted edge itself will be curved by the lens distortion, causing further measurement problems. This study summarises the difficulties in the use of MTF for sharpness measurement in fisheye lens cameras, and proposes mitigations and alternative methods.

关键词： modulation transfer function Spatial Frequency Response fisheye lens image sharpness resolution

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Binary pseudorandom test standard to determine the modulation transfer function of optical microscopes

Binary pseudorandom test standard to determine the modulatio...

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Conference on Applied Advanced Optical Metrology Solutions

作者： Lacey, Ian Anderson, Erik H. Artemiev, Nikolay A. Babin, Sergey Cabrini, Stefano Calafiore, Guiseppe Chan, Elaine R. McKinney, Wayne R. Peroz, Christophe Takacs, Peter Z. Yashchuk, Valeriy V. Univ Calif Berkeley Lawrence Berkeley Natl Lab Berkeley CA 94720 USA ABeam Technol Inc Hayward CA 94541 USA Brookhaven Natl Lab Upton NY 11973 USA

ISBN: (纸本)9781628417425

This work reports on the development of a binary pseudo-random test sample optimized to calibrate the MTF of optical microscopes. The sample consists of a number of 1-D and 2-D patterns, with different minimum sizes of spatial artifacts from 300 nm to 2 microns. We describe the mathematical background, fabrication process, data acquisition and analysis procedure to return spatial frequency based instrument calibration. We show that the developed samples satisfy the characteristics of a test standard: functionality, ease of specification and fabrication, reproducibility, and low sensitivity to manufacturing error.

关键词： modulation transfer function interferometric microscope coded aperture imaging calibration test standard correlation analysis surface metrology systematic error

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