查找图像中的像素索引表明一种情况

您在正确的轨道上并不太难。如果您拥有图像处理工具箱，我建议您看一下形态运算符。特别是您要使用我的代码来体现您需要的所有详细信息。

%rather than using find, we create a binary mask. Its not the indicies of
%the matching elements as find gives. its is 1/true if the value matches the
%criteria, and 0/false otherwise.
mask = (im=1 | im=-1);

%create a 3x3 rectangle structuring element. We use a 3x3 because we want
%to expand the image by one pixel. basically the structring element (Strel)
%is our kernal, if you know image processing this is the same thing. 
%a = [0 0 0 0;
%     0 1 1 1;
%     0 1 1 1;
%     0 1 1 1];
%our kernal is center at 2,2 (for this example) which are these elements
%     0 0 0  of a  think a(1:3,1:3) now what the dialate operation
%     0 1 1  says is, if the majority of these pixels are ones... they
%     0 1 1  should probabaly all be ones so all those 0s will become ones
%the size of the kernal 3x3 ensures we are only growing our image one
%pixel, hope that makes sense    
se = strel('square',3);

%now we dilate, or 'expand' our mask with our structuring element
expanded_mask = imdilate(mask,se);

%if you still want the indicies you can use find on our expanded mask
idx = find(expanded_mask==1);

编辑：没有形态学操作/图像处理工具箱此方法使用大量的for循环，因此它不是最快的，并且不执行错误检查，但它可以工作。我的膨胀函数说，如果大多数像素都是像素，那就把它们都变成像素。

function expanded_mask=DilateBinaryImage(bin_im, kernal_size)
    [max_row,max_col] = size(bin_im);

    %since we are opening the mask (only adding 1s), we can start off with the
    %same values of the mask, and simply add extra 1's as needed
    expanded_mask = bin_im;

    %we don't want to go off the edge of our image with this kernal
    %so we offset it a bit
    kern_padding = floor(kernal_size/2);

    %this ignores the edges
    for (curr_row=kern_padding+1:1:max_row - kern_padding)
       for (curr_col=kern_padding+1:1:max_col - kern_padding)
          %we do 2 sums, one for rows, one for columns
          num_ones = sum(sum(bin_im(curr_row-kern_padding:curr_row+kern_padding,curr_col-kern_padding:curr_col+kern_padding)));

          %if the majority of vlaues are 1, we use floor to help with corner
          %cases
          if (num_ones >= floor((kernal_size*kernal_size)/2))
              %make all the values one
              expanded_mask(curr_row-kern_padding:curr_row+kern_padding,curr_col-kern_padding:curr_col+kern_padding) = 1;
          end
       end
    end


end

然后这样称呼它

kernal_size= 3;
mask = (I==1 | I==-1);
expanded_mask = DilateBinaryImage(mask, kernal_size);
idx = find(expanded_mask==1);

我的膨胀函数在二进制图像的边缘不起作用。它只是复制它们。