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Improved analytical modulation transfer function for image intensified charge coupled devices

TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES 2010年第1期18卷 71-81页

作者： Gul, Nebi Efe, Murat Ankara Univ Dept Elect Engn Fac Engn TR-06100 Ankara Turkey

The basic problem of simulation and modeling of Image Intensified Charge Coupled Device (ICCD) is the difference between the analytical modulation transfer function (MTF) formulation used in the model and the experimentally obtained MTF An investigation into the MTF of ICCD sub-components reveal that the MTF of the Image Intensifier Tube (IIT) is the main factor ut this deviation. In this study a regulation factor for the MTF of 3(rd) generation IITs has been developed A commonly used MTF formulation for IITs has been modified to include a regulation factor which has helped produce more precise MTF values for the Night Vision Sight (NVS) device The results obtained through the new formulation have been compared with the experimental results and it is revealed that the proposed formulation yields MTF values within 3% of the experimental results, on average, while the most commonly used formulation produces approximately 29 5% difference, which amounts to almost 10% improvement in analytical analysis The analysis is then, extended to other generations of IITs where similar improvements have been achieved

关键词： Image intensified charge coupled device (ICCD) image intensified tube modulation transfer function simulation

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Regularized slanted-edge method for measuring the modulation transfer function of imaging systems

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APPLIED OPTICS 2018年第22期57卷 6552-6558页

作者： Xie, Xufen Fan, Hongda Wang, Anding Zou, Nianyu Zhang, Yuncui Dalian Polytech Univ Res Inst Photon 1 Qinggongyuan Dalian 116034 Peoples R China Harbin Inst Technol Res Ctr Space Opt Engn 2 Yikuang St Harbin 150080 Heilongjiang Peoples R China

The slanted-edge method for modulation transfer function (MTF) measurement uses edge target images whose gray values are often affected by noise and other factors, decreasing its accuracy. We first analyze the ill-posedness in the edge spread function (ESF) regression caused by noise. Second, we propose a regularized slanted-edge method to solve this problem by incorporating a Tikhonov regularization term. Combined with varying precision weights, the ESF is solved using the variational principle, and the MTF is estimated using the regularized ESF. The regularized slanted-edge method is verified for Gaussian, gamma, and Rayleigh noise. The results show that our method improves the accuracy by 0.01-9.02% and 4.33% on average. The proposed method is more robust to noise and accurate than the slanted-edge method. (C) 2018 Optical Society of America

关键词： Image processing Image quality Imaging systems modulation techniques modulation transfer function Spatial frequency

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Dynamic modulation transfer function of a retina-like sensor

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APPLIED OPTICS 2014年第9期53卷 1947-1953页

作者： Wang, Fan Cao, Fengmei Bai, Tingzhu Hao, Qun Beijing Inst Technol Key Lab Photoelect Imaging Technol & Syst Minist Educ China Sch Optoelect Beijing 100081 Peoples R China

In this paper, we propose a method to deduce the dynamic modulation transfer function (DMTF) of a space-variant sampling retina-like sensor and demonstrate its utilization in the forward motion imaging process. With the analysis of sampling and the motion imaging property of the sensor, DMTF has been derived. Next, the performance of DMTF between a retina-like sensor and a rectilinear sensor is compared, and the results show that the degradation of DMTF in forward motion is less than that of a rectilinear sensor. Then, the output images are obtained through simulation based on DMTF, and they are compared with that obtained from a CMOS camera with the same forward motion conditions. The Pearson correlation coefficients between the two kinds of images are all larger than 0.85. Thus, the effectiveness of DMTF is shown. (C) 2014 Optical Society of America

关键词： transfer functionS correlation coefficient (r) Sensors dynamic modulation distributed management task force modulation transfer function Retina

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Line-Based modulation transfer function Measurement of Pixelated Displays

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IEEE ACCESS 2020年 8卷 196351-196362页

作者： Masaoka, Kenichiro NHK Sci & Technol Res Labs Tokyo 1578510 Japan

This paper proposes a line-based method for measuring the modulation transfer function (MTF) of a display. In this method, the spatial distribution of a single line that is displayed in a small region of the screen is analyzed. This is performed by capturing the displayed line by a light measuring device (LMD). The square sampling grid of the LMD is set slightly slanted relative to the displayed line so that the line is recorded with various offsets with respect to the sampling positions. By analyzing a supersampled 1D line spread function generated from a small region of interest (ROI) in the image of the captured line, the display MTF is estimated. The convolution theorem is used to compensate the display MTF for the underestimation related to the spatial performance or MTF of the LMD. Thereby, accurate display MTF results are obtained for a wide range of pixel ratio, i.e., the number of pixels of the measurement device per display pixel interval. The proposed method was validated using computer-generated images of a model display with an RGB stripe subpixel arrangement and a model LMD. The utilization of a low pixel ratio enables the measurement to be performed using a small lens and long working distance. In addition, the small size of the employed ROI significantly reduces the computational cost and allows the use of a low-resolution camera.

关键词： Image edge detection modulation Cameras Performance evaluation transfer functions Convolution Digital display light measuring device modulation transfer function

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IMAGING THROUGH THE ATMOSPHERE - PRACTICAL INSTRUMENTATION-BASED THEORY AND VERIFICATION OF AEROSOL modulation transfer-function - REPLY TO COMMENT

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 1995年第5期12卷 1017-1023页

作者： KOPEIKA, NS SADOT, D []Department of Electrical and Computer Engineering Ben-GurionUniversity of the Negev P.O. Box 653 Beer-Sheva Israel

New exact numerical calculations as well as exact calculations in J. Opt. Sec. Am. A 10, 172 (1993) indicate that the approximations in the Comment in J. Opt. Sec. Am. A 11, 1175 (1994) are based on faulty perceptions of basic scattering phenomena and on a misreading of our paper. The Comment does not sufficiently consider effects of instrumentation. Whereas our model refers to the aerosol modulation transfer function (MTF) in the image plane, the values of maximum angles for scattered (theta(s)) and unscattered (theta(0)) light used in the Comment refer to the optics plane. The Comment does not consider the fact that dynamic range limits (theta(s)) in the image, whereas limited spatial-frequency bandwidth broadens theta(0) in the image, each by orders of magnitude. Therefore the Comment's conclusion contradicts experimental results obtained by numerous researchers. The Comment's conclusion that aerosol MTF is insignificant is based on that author's own experiments, in which clear weather and haze atmospheric MTF (composed of turbulence and aerosol MTF's) could not be measured, the reason being insufficient equipment resolution, rather than insignificant turbulence or aerosol MTF. Furthermore, the claim in our original paper that aerosol MTF is extremely significant has since been supported by many different types of experiments that included short and long exposures, thermal imaging, and image restoration based on atmospheric MTF, including a highly significant practical, uniquely shaped, aerosol MTF.

关键词： Forward scattering Image quality Image restoration modulation transfer function Radiative transfer Thermal imaging

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Texture analysis in radiographs: The influence of modulation transfer function and noise on the discriminative ability of texture features

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MEDICAL PHYSICS 1998年第6期25卷 922-936页

作者： Veenland, JF Grashuis, JL Gelsema, ES Erasmus Univ Dept Med Informat NL-3000 DR Rotterdam Netherlands Erasmus Univ Dept Radiol NL-3000 DR Rotterdam Netherlands

Tissue structures, represented by textures in radiographs, can be quantified using texture analysis methods. Different texture analysis methods have been used to discriminate between different aspects of various diseases in primarily x rays of chest, bone, and breasts. However, most of these methods have not specifically been developed for use on radiographs. Certain characteristics of the radiographic process, e.g., noise and blurring, influence the visible texture. In order for a texture analysis method to be able to discriminate between different underlying textures, it should not be too sensitive for such processes as image noise and blur. In this study, we investigated the sensitivity of four different texture analysis methods for image noise and blur. First, a baseline measurement was performed of the discriminative performance of the Spatial Gray-Level Dependence method, the Fourier Power Spectrum, the Fractal Dimension, and the Morphological Gradient Method on images, which were not affected by radiographic noise and blur. Two types of images were used: fractal and Brodatz. Whereas the Brodatz images represent very different textures, the differences between the fractal images are more gradual. We assume that the behavior of the different texture analysis methods on the fractal images is representative for their performance on radiologic textures. On these types of images we simulated the effect of four different noise levels and the effect of two different modulation transfer functions, corresponding with different screen-film combinations. The influence on the discriminative performance of the four texture analysis methods was evaluated. The influence of noise on the discriminative performance is, as expected, dependent on the image type used: the discrimination of more gradually different images, such as the fractal images, is already lowered for relatively low noise levels. In contrast, when the images are more different, only high noise levels decrease

关键词： texture analysis radiographs modulation transfer function noise

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Evaluation of image quality of color liquid crystal displays by measuring modulation transfer function

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OPTICAL ENGINEERING 1999年第10期38卷 1671-1678页

作者： Kim, TH Lee, YW Cho, HM Lee, IW Korea Res Inst Stand & Sci Quantum Metrol Div Taejon 305600 South Korea

The image quality of color liquid crystal displays (LCDs) are evaluated by measuring the modulation transfer function (MTF). The measurement system is constructed with a linear charge coupled device (CCD) and the spectral response is corrected with a V(lambda) filter for the human eye. The scanning width of a white dot is determined by considering the characteristics of LCDs. The MTF of the LCDs are measured at five positions on the screen as well as different combinations of contrast and brightness levels. The results are presented and discussed. We show that the MTF measuring method is very useful to evaluate the image quality of color LCDs. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)02211-4].

关键词： liquid crystal display modulation transfer function image quality modulation transfer function area resolution display system

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Accuracy and Precision of Edge-Based modulation transfer function Measurement for Sampled Imaging Systems

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IEEE ACCESS 2018年 6卷 41079-41086页

作者： Masaoka, Kenichiro Japan Broadcasting Corp NHK Tokyo 1578510 Japan

The real-time, edge-based, multidirectional modulation transfer function (MTF) measurement system has elucidated the MTF characteristics of sampled imaging systems. However, the accuracy and precision of edge-based MTF measurements are not well understood quantitatively because of the complicated shift-variant nature of the sampling process by the image sensor and the binning process in the edge-based method for producing a supersampled edge spread function. The edge-based MTF measurement is valid only when the edge positions imaged are assumed to be distributed uniformly relative to the sampling sites. This study demonstrates that precision, which is dependent on the edge angle, is counterintuitively high at a higher oversampling ratio of the binning regardless of the smaller pixel counts per bin even with camera noise, and that significantly high precision can be achieved by taking an ensemble average of MTFs computed over a single cycle of the binning phase, even at low oversampling ratios, with high accuracy through proper corrections to compensate for the attenuation of the MTF values due to the discrete processing of the edge-based method.

关键词： modulation transfer function superresolution

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Dynamic modulation transfer function Analysis of Images Blurred by Sinusoidal Vibration

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JOURNAL OF THE OPTICAL SOCIETY OF KOREA 2016年第6期20卷 762-769页

作者： Du, Yanlu Ding, Yalin Xu, Yongsen Sun, Chongshang Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

The dynamic modulation transfer function (MTF) for image degradation caused by sinusoidal vibration is formulated based on a Bessel function of the first kind. The presented method makes it possible to obtain an analytical MTF expression derived for arbitrary frequency sinusoidal vibration. The error obtained by the use of finite order sum approximations instead of infinite sums is investigated in detail. Dynamic MTF exhibits a stronger random behavior for low frequency vibration than high frequency vibration. The calculated MTFs agree well with the measured MTFs with the slant edge method in imaging experiments. With the proposed formula, allowable amplitudes of any frequency vibration are easily calculated. This is practical for the analysis and design of the line-of-sight stabilization system in the remote sensing camera.

关键词： Imaging system modulation transfer function Sinusoidal vibration Slant edge method

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Simulation of the modulation transfer function dependent on the partial Fourier fraction in dynamic contrast enhancement magnetic resonance imaging

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AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016年第4期39卷 825-831页

作者： Takatsu, Yasuo Ueyama, Tsuyoshi Miyati, Tosiaki Yamamura, Kenichirou Osaka Red Cross Hosp Dept Radiol Tennouji Ku 5-30 Fudegasaki Osaka 5438555 Japan Kanazawa Univ Grad Sch Med Sci Div Hlth Sci 5-11-80 Kodatsuno Kanazawa Ishikawa 9200942 Japan Saito Yukoukai Hosp Dept Radiol 7-2-18 Saito Asagi Ibaraki Osaka 5670085 Japan Osaka Med Coll Hosp Dept Radiol 2-7Daigaku Cho Takatsuki Osaka 5698686 Japan

The image characteristics in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) depend on the partial Fourier fraction and contrast medium concentration. These characteristics were assessed and the modulation transfer function (MTF) was calculated by computer simulation. A digital phantom was created from signal intensity data acquired at different contrast medium concentrations on a breast model. The frequency images [created by fast Fourier transform (FFT)] were divided into 512 parts and rearranged to form a new image. The inverse FFT of this image yielded the MTF. From the reference data, three linear models (low, medium, and high) and three exponential models (slow, medium, and rapid) of the signal intensity were created. Smaller partial Fourier fractions, and higher gradients in the linear models, corresponded to faster MTF decline. The MTF more gradually decreased in the exponential models than in the linear models. The MTF, which reflects the image characteristics in DCE-MRI, was more degraded as the partial Fourier fraction decreased.

关键词： Magnetic resonance imaging Dynamic study Partial Fourier fraction modulation transfer function

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