Question

我有一个带有一个非零条目的矩阵;

InfectionMatrix = zeros(10,10);
InfectionMatrix(5,5) = 1;

我想看看这个矩阵找到所有值为1的元素然后将周围元素的值增加0.125

for k = 1:1:8
    for j = 1:1:10
        for i = 1:1:10
            if InfectionMatrix(i,j) == 1
                InfectionMatrix(i-1,j) = InfectionMatrix(i-1,j)+      0.125; 
                InfectionMatrix(i-1,j+1) = InfectionMatrix(i-1,j+1)+  0.125; 
                InfectionMatrix(i-1,j-1) = InfectionMatrix(i-1,j-1)+  0.125; 
                InfectionMatrix(i,j+1) = InfectionMatrix(i,j+1)+      0.125; 
                InfectionMatrix(i,j-1) = InfectionMatrix(i,j-1)+      0.125; 
                InfectionMatrix(i+1,j+1) = InfectionMatrix(i+1,j+1) + 0.125; 
                InfectionMatrix(i+1,j-1) = InfectionMatrix(i+1,j-1) + 0.125;
                InfectionMatrix(i+1,j) = InfectionMatrix(i+1,j) +     0.125; 
            end
        end
    end  
end

这就是我所做的，也就是我所说的周围元素。我只能想到使用一个循环这样做，但这样它可以按顺序查看元素并且不会给出一个＆＃39; wave＆＃39;影响。

这是一种想法;

0 0 0 0 0

0 0 1 0 0 ---＆gt;

0 0 0 0 0

0 1 1 1 0

0 1 1 1 0 ----＆gt;

0 1 1 1 0

1 1 1 1 1

1 1 1 1 1 ----＆gt;

1 1 1 1 1

矩阵表示多次迭代。

最大值可以是1，所有值都从中心传播，每次增加0.125。

Answer 1

试试这个

for k = 1:1:8
    IMONES = (InfectionMatrix==1);
    KERNEL = 0.125*ones(3,3);
    KERNEL(2,2) = 0;
    InfectionMatrix += conv2(IMONES,KERNEL,'same');
end

请注意，我已将“波浪效应”解释为影响两个最里面迭代中前面元素的后续元素。我以为你不希望这种情况发生。上述解决方案没有“波浪效应”

Answer 2

这应该可以解决问题：

function im = spread(im)
    % Retrieve the matrix data...
    [im_rows,im_cols] = size(im);
    im_min = min(im(im>0));

    % Declare the indces...
    indices = [];

    for i = 1:im_rows
        for j = 1:im_cols
            % Skip the process if the current center is not equal to 1...
            if (im(i,j) ~= im_min)
                continue;
            end

            % Retrieve the neighboring column and row offsets...
            c = bsxfun(@plus,j,[-1  0  1 -1  1 -1  0  1]);
            r = bsxfun(@plus,i,[-1 -1 -1  0  0  1  1  1]);

            % Filter the invalid positions...
            idx = (c > 0) & (c <= im_cols) & (r > 0) & (r <= im_rows);

            % Transform the valid positions into linear indices and discard the invalid ones...
            idx = (((idx .* c) - 1) .* im_rows) + (idx .* r);
            idx = reshape(idx.',1,numel(idx));

            % Keep only the valid indices...
            idx = idx(idx > 0);
            idx = idx(im(idx) == 0);
            indices = [indices, idx];  
        end
    end

    % Increase the non-minimum (and non-zero) values...
    im(im >= im_min) = im(im >= im_min) + 0.125;

    % Take the elements with a value equal to 0 and increase them...
    im(indices) = im(indices) + 0.125;
end

以下是一个示例用法：

im = zeros(10,10);
im(5,5) = 0.125;

figure();
colormap(hot());

hold on;

for i = 1:8
    im = spread(im);

    subplot(4,2,i);
    imagesc(im);
    title(['Step ' num2str(i)]);
end

hold off;

caxis([0 max(max(im))]);

同时查看矩阵中的所有元素

2 个答案: