Method for measuring modulation transfer function of imaging system based on distance weighting

A modulation transfer function and imaging system technology, applied in image communication, television, electrical components, etc., can solve problems such as inaccurate MTF measurement results, and achieve the effects of reducing impact, accurate calculation, and good stability

Active Publication Date: 2018-06-15
ZHEJIANG UNIV
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Problems solved by technology

[0006] The technical problem solved by the present invention is: Aiming at the inaccurate measurement result of the MTF due to the inaccurate measurement results of the MTF of the digital imaging system by the inclined edge method when measuring the MTF of the digital imaging system, a method for measuring the modulation transfer function of the imaging system based on distance weighting is proposed

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  • Method for measuring modulation transfer function of imaging system based on distance weighting
  • Method for measuring modulation transfer function of imaging system based on distance weighting
  • Method for measuring modulation transfer function of imaging system based on distance weighting

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Embodiment Construction

[0045] The technical solution of the present invention will be described in detail below in conjunction with the drawings and embodiments. see figure 1 , the process of the embodiment can be divided into five steps:

[0046] Step 1: Obtain the edge image to be tested, including the following sub-steps:

[0047] 1.1 Imaging through the imaging system to be tested to obtain the image to be tested;

[0048] 1.2 In the image to be tested, manually or automatically select an edge area with a size of m×n pixels;

[0049] 1.3 For the selected edge image, use the OECF of the sensor to perform linearization processing to obtain an edge image to be measured with a size of m×n pixels;

[0050] Step 2: Determine the position of the edge of the blade, including the following sub-steps:

[0051] 2.1 Row-by-row derivation to obtain the LSF with a sequence length of n, and dot multiplication with the Hamming window function with a central symmetric sequence length of n to obtain a windowe...

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Abstract

The invention discloses a method for measuring the MTF (Modulation Transfer Function) of an imaging system based on distance weighting, which comprises the following steps: (1) an appropriate edge region in an image obtained by shooting is selected, and the image data is linearized by using a photoelectric conversion function of a sensor to obtain an edge image to be measured; (2) in the edge image obtained in the step 1, the edge position of the edge is obtained by finding the median point of the ESF (Edge Spread Function) of each line successively; (3) an edge position function is obtained by carrying out least square fitting on the edge position of the edge obtained in step 2; (4) the distance from each pixel on the image to the edge is calculated, and the ESF with equidistant samplingis obtained according to the distance weighting; (5) derivation is performed on the ESF obtained in step 4 to obtain a LSF (Line Spread Function), and Fourier transform is performed on the LSF to obtain the MTF of the imaging system. The invention realizes MTF measurement of images containing edge regions, and has the advantages of not being limited by edge angles, good noise resistance, accuratecalculation, good stability, etc.

Description

technical field [0001] The invention belongs to the field of imaging system quality evaluation, in particular to a modulation transfer function measurement method for an optical digital imaging system. Background technique [0002] In actual imaging, the image quality is often affected by many aspects: aberration and diffraction effects of the imaging system; resolution, nonlinear response and various noises of the sensor; external jitter and other interference during shooting, etc. For imaging system image quality evaluation, modulation transfer function MTF (Modulation Transfer Function) is an important index. It objectively reflects the attenuation of different spatial frequency signals after passing through the imaging system, represents the transmission characteristics of the imaging system to the input signal during the imaging process, and is one of the indicators commonly used in the world to evaluate the performance of imaging systems. According to the imaging degr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N17/00
Inventor 冯华君张峥徐之海李奇陈跃庭
Owner ZHEJIANG UNIV
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