如何更正与数字图像处理相关的代码？

问：

我的目标是获得给定的照片，其中包括左上半部分的黑色和右下半部分的白色。在照片中，可以清楚地看到，黑色（0）通过对角线以及x和y坐标将是白色（255）。它是在matlab中通过进行数字图像处理来完成的，但我无法获得100%的处理。 1）你应该把照片作为灰度照片（在代码grayImage2中）。然后，您需要应用您的程序才能获得我上面提到的获取照片的结果。 2）另外，我的灰度图像尺寸为400x400。你能帮我更正代码吗？提前致谢。

[x,y,z]= size(grayImage2);

centerX2 = y;

centerY2 = x;

radius2 = 0;  % Change this value to set the desired radius

% Calculate the maximum radius from the center to the corners

maxRadius = sqrt((centerX2 - 1)^2 + (centerY2 - 1)^2);

% Iterate through the diagonal and change pixel values to gray tones

% Iterate through all pixels

for i = 1:x
     for j = 1:y
        if(j>=256)% because of being 400 for one edge for size 
          % Calculate the distance from the center to the current pixel  
          distance2 = sqrt((j - centerX2)^2 + (i - centerY2)^2);
          % Calculate the gray value based on the distance
          grayValue = uint8((distance2 / maxRadius) * (255-(400-j)));
          % Set the pixel to the calculated gray value
          grayImage2(i, j) = grayValue;
        else
          % Calculate the distance from the center to the current pixel
          distance2 = sqrt((j - centerX2)^2 + (i - centerY2)^2);
          % Calculate the gray value based on the distance
          grayValue = uint8((distance2 / maxRadius) * (255-(255-j+1)));
          % Set the pixel to the calculated gray value
          grayImage2(i, j) = grayValue;
        end
   end
end

figure;

% Display the grayscale image

imshow(grayImage2);

title('Grayscale Image with Radial Gradient');