刃边法mtf计算matlab实现

以下是一个MATLAB函数，用于计算刃边法（MTF）：

function [mtf, freq] = blade_edge_mtf(image, pixel_size, distance, wavelength)
% BLADE_EDGE_MTF Calculate the Modulation Transfer Function (MTF) using the Blade Edge method.
%   [MTF, FREQ] = BLADE_EDGE_MTF(IMAGE, PIXEL_SIZE, DISTANCE, WAVELENGTH) calculates the MTF of an image using the Blade Edge method.
%
%   Inputs:
%       IMAGE - The input image.
%       PIXEL_SIZE - The size of a pixel in the image, in millimeters.
%       DISTANCE - The distance between the object and the sensor, in millimeters.
%       WAVELENGTH - The wavelength of the light used to capture the image, in nanometers.
%
%   Outputs:
%       MTF - The calculated MTF.
%       FREQ - The frequencies corresponding to the MTF values.

% Convert wavelength from nanometers to millimeters
wavelength = wavelength / 1000000;

% Calculate the spatial frequency range
M = size(image, 1);
N = size(image, 2);
freq_x = -0.5:1/N:0.5-1/N;
freq_y = -0.5:1/M:0.5-1/M;
[freq_x, freq_y] = meshgrid(freq_x, freq_y);
freq = sqrt(freq_x.^2 + freq_y.^2) / pixel_size;

% Calculate the knife-edge spread function
ke = abs(fftshift(fft2(image))).^2;
ke = ke / max(ke(:));
ke = ke(:, round(N/2));

% Calculate the MTF
mtf = abs(fft(ke));
mtf = mtf / mtf(1);
mtf = mtf(:);

% Calculate the corresponding frequencies
freq = freq(:) / (distance * wavelength);
end

这个函数需要输入四个参数：

- `image` - 要计算MTF的图像。
- `pixel_size` - 图像中一个像素的大小，以毫米为单位。
- `distance` - 对象和传感器之间的距离，以毫米为单位。
- `wavelength` - 用于捕获图像的光的波长，以纳米为单位。

函数返回两个变量：

- `mtf` - 计算出的MTF。
- `freq` - 对应于MTF值的频率。