Imaging quality simulation method of Fresnel diffraction optical system

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

Active Publication Date: 2017-08-04
HARBIN INST OF TECH
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  • Summary
  • 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 syste

Method used

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  • Imaging quality simulation method of Fresnel diffraction optical system
  • Imaging quality simulation method of Fresnel diffraction optical system
  • Imaging quality simulation method of Fresnel diffraction optical system

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specific Embodiment approach 1

[0030] Specific implementation mode one: as figure 1 As shown, what is described in this embodiment is a method for simulating the imaging quality of a Fresnel diffractive optical system, and the steps of the method are as follows:

[0031] Step 1: Based on the idea of ​​equal halo area blocks, the original image is divided into several image blocks with approximately the same point spread function;

[0032] Step 2: Calculate the position of the meridian plane at 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: Low-pass filtering is performed on each image block by using the MTF of different regions of the image, and random noise is added.

specific Embodiment approach 2

[0035] Specific implementation mode two: as figure 1 As shown, the imaging quality simulation method of a Fresnel diffractive optical system described in the first embodiment, the specific steps of the first step are as follows:

[0036] (1) Based on the block idea of ​​equal halo area, 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 field of view is (ω x , ω y ), the optical system transfer function (MTF); Noi is the noise spectrum; X represents the original image spectrum;

[0040] (2) Design overlapping regions between adjacent image blocks of several image blocks with approximately the same point spread function; take the center of the image as the origin, ...

specific Embodiment approach 3

[0041] Specific implementation mode three: as figure 1 As shown, the imaging quality simulation method of a Fresnel diffractive optical system described in the second embodiment, 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] Let the focal length of the diffractive optical imaging system be f, and the pixel size be P 1 , then the center coordinates are (x a ,y b ) image block in 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, from the spatial geometric relationship, it can be known 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 in particular relates to an imaging quality simulation method of a Fresnel diffraction optical system. Background technique [0002] The simulation estimation of optical remote sensing imaging quality has important guiding significance and application value in the prediction of remote sensing tasks such as reconnaissance, surveying and mapping, surveillance, imaging system optimization design and performance evaluation, and image processing algorithm verification. With the continuous improvement of space resolution requirements for high-orbit surveillance, there is an urgent need for space optical payloads to have the characteristics of super large aperture, light weight, 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...

Claims

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Application Information

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IPC IPC(8): G06F17/50
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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