数字图像处理第三章 sobel算子

function [ edge ] = SobelOperator( pic )
%%sobel
    edge = uint8(zeros(size(pic)));

    h = size(pic, 1);
    w = size(pic, 2);

    gx = [-1, -2, -1; 0, 0, 0; 1, 2, 1];%sobel算子水平梯度模板3*3,中间权重大,prewitt算子是中间2变为1
    gy = gx';

    for i = 2 : h - 1
        for j = 2 : w - 1
            sub = double(pic(i - 1 : i + 1, j - 1 : j + 1));
            g1 = abs(sum(sum(sub .* gx)));%x，y两维，两个sum
            g2 = abs(sum(sum(sub .* gy)));
            if g1 > g2
                edge(i, j) = uint8(g1);
            else
                edge(i, j) = uint8(g2);
            end
        end
    end
end

Robert

function [ edge ] = RobertsOperator( pic )
%%robet算子求微分
    edge = uint8(zeros(size(pic)));

    h = size(pic, 1);
    w = size(pic, 2);

    for i = 1 : h - 1
        for j = 1 : w - 1
            edge(i, j) = uint8(abs(pic(i, j) - pic(i + 1, j + 1)) + abs(pic(i, j + 1) - pic(i + 1, j)));
        end
    end

end

拉普拉斯

function [ edge ] = LaplaceOperator( pic )
    edge = uint8(zeros(size(pic)));

    h = size(pic, 1);
    w = size(pic, 2);

    l = [0, 1, 0; 1, -4, 1; 0, 1, 0];

    for i = 2 : h - 1
        for j = 2 : w - 1
            sub = double(pic(i - 1 : i + 1, j - 1 : j + 1));
            d = sum(sum(sub .* l));
            edge(i, j) = uint8(d);
        end
    end
end