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A Simulation Method for Imaging Quality of Fresnel Diffractive Optical System

A Fresnel diffraction and optical system technology, applied in the field of imaging quality simulation of Fresnel diffraction optical systems, to achieve the effects of low contrast, low SNR, and low MTF

Active Publication Date: 2020-08-07
HARBIN INST OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to propose a method for imaging quality simulation of a Fresnel diffractive optical system aiming at the blank of theoretical research on the imaging quality simulation method of the current diffractive optical imaging system

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  • A Simulation Method for Imaging Quality of Fresnel Diffractive Optical System
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  • A Simulation Method for Imaging Quality of Fresnel Diffractive Optical System

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specific Embodiment approach 1

[0030] Specific implementation manner one: such as figure 1 As shown, this embodiment records an imaging quality simulation method of a Fresnel diffraction optical system, and the method steps are as follows:

[0031] Step 1: Divide the original image into several image blocks with approximately the same point spread function based on the idea of ​​iso-halo distinguishing blocks;

[0032] Step 2: Calculate the meridian position of the center of each image block and its corresponding field of view;

[0033] Step 3: Construct a discretized Fresnel diffraction formula and calculate the point spread function of each image block;

[0034] Step 4: Use the MTF of different areas of the image to perform low-pass filtering on each image block, and add random noise.

specific Embodiment approach 2

[0035] Specific implementation manner two: such as figure 1 As shown, in a method for simulating imaging quality of a Fresnel diffraction optical system described in the first embodiment, the specific steps of the first step are as follows:

[0036] (1) Based on the idea of ​​isotropically distinguishing blocks, the original image is divided into several image blocks with approximately the same point spread function:

[0037] The Fresnel diffraction imaging system has obvious PSF spatial shift characteristics, and its degradation model can be expressed as:

[0038] Y=H(ω x , Ω y )X+Noi

[0039] In the formula, Y is the degraded image spectrum; H(ω x , Ω y ) Means the angle of view is (ω x , Ω y ), the optical system transfer function (MTF); Noi is the noise spectrum; X is the original image spectrum;

[0040] (2) First design overlapping areas between adjacent image blocks of several image blocks with approximately the same point spread function; take the image center as the origin to e...

specific Embodiment approach 3

[0041] Specific implementation manner three: such as figure 1 As shown in the second embodiment of a Fresnel diffraction optical system imaging quality simulation method, the specific steps of the second step are as follows:

[0042] (1) Calculate the field angle of each image block in the x-axis and y-axis directions:

[0043] Suppose the focal length of the diffractive optical imaging system is f and the pixel size is P 1 , The center coordinate is (x a , Y b ) Of the image block in the x, y direction field angle ω x And ω y They are:

[0044]

[0045]

[0046] (2) Calculate the field angle of each image block on the meridian plane:

[0047] Such as figure 2 As shown, it can be seen from the spatial geometric relationship that the angle of view α on the meridian plane and the angle β between the meridian plane and the y-axis are:

[0048]

[0049]

[0050] In the formula, sign(·) is a sign function.

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Abstract

The invention belongs to the technical field of optical imaging simulation, and relates to an imaging quality simulation method of a Fresnel diffraction optical system. The method includes the following steps that 1, based on the isoplanatic region block thought, an original image is divided into multiple image blocks with the similar same point diffusion function; 2, the meridian plane position of the center of each image block and the corresponding field angle are calculated; 3, a discretized Fresnel diffraction formula is constructed, and the point spread function of each image block is calculated; 4, MTF in different regions of the image are used for conducting lowpass filtering on all the image blocks, and random noise is added. The imaging quality simulation method is suitable for imaging quality simulation of an optical system with a diffraction lens as the main lens, capable of generating images with diffraction optical imaging characteristics including low MTF, low contrast, low SNR and large-size PSF spatial variability in a simulation mode, and provides support for optimal design of the Fresnel diffraction imaging system and image processing algorithm research and verification.

Description

Technical field [0001] The invention belongs to the technical field of optical imaging simulation, and specifically relates to an imaging quality simulation method of a Fresnel diffraction optical system. Background technique [0002] The simulation and estimation of optical remote sensing imaging quality has important guiding significance and application value in reconnaissance, surveying, mapping, surveillance and other remote sensing mission prediction, imaging system optimization design and performance evaluation, and image processing algorithm verification. As the demand for spatial resolution in high-orbit surveillance continues to increase, there is an urgent need for spatial optical loads to have the characteristics of ultra-large aperture, lightweight, short processing cycle, and low cost. Traditional reflective or refractive imaging systems can no longer fully meet these requirements. Requirements, and diffractive optical imaging technology can overcome this limitation,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/20
CPCG06F30/20
Inventor 智喜洋江世凯张伟胡建明孙晅付斌
Owner HARBIN INST OF TECH
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