matlab中的localthresh函数代码实现

以下是使用matlab实现localthresh函数的代码：

function BW = localthresh(I, sensitivity, radius, method)
    % Convert the input image to double precision
    I = im2double(I);

    % Compute the size of the image
    [M, N] = size(I);

    % Initialize the output image
    BW = zeros(M, N);

    % Compute the indices of the pixels in the local neighborhood
    [X, Y] = meshgrid(-radius:radius, -radius:radius);
    idx = find(X.^2 + Y.^2 <= radius^2);

    % Compute the local threshold for each pixel
    for i = 1:M
        for j = 1:N
            % Compute the indices of the pixels in the local neighborhood
            xi = max(1, i-radius):min(M, i+radius);
            yj = max(1, j-radius):min(N, j+radius);

            % Extract the local neighborhood
            neighborhood = I(xi, yj);

            % Compute the mean and standard deviation of the neighborhood
            mean_val = mean(neighborhood(:));
            std_val = std(neighborhood(:));

            % Compute the local threshold
            if strcmp(method, 'adaptive')
                T = mean_val * (1 - sensitivity * (std_val / 128 - 1));
            else
                error('Unknown method');
            end

            % Compute the binary value for the pixel
            if I(i, j) > T
                BW(i, j) = 1;
            end
        end
    end
end

该函数使用双重循环遍历图像中的每个像素，对于每个像素，提取其周围半径为radius的局部区域，计算局部区域的平均灰度值和标准差，然后根据局部阈值对像素进行二值化处理。最后返回二值化后的图像BW。