Why isn't matlab drawing the bounding box on my picture?

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Andrew Killian 2021-9-5

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1447169-why-isn-t-matlab-drawing-the-bounding-box-on-my-picture

评论： Image Analyst 2021-9-6

I followed these commands in tutorial exactly how he did it to draw a bounding box around the main object of a pic but nothing happened for me. The picture looks the same. Will these commands work or not depending on the picture you are using?

>> walk = imread('walkstraight/frame0062.tif');
>> gray_walk = rgb2gray(walk)
>> bw_walk = im2bw(gray_walk, 0.8);
>> bw = ~bw_walk;
>> bw = bwareaopen(bw, 1000);
>> [bwLabel, num] = bwlabel(bw, 8);
>> s = regionprops(bwLabel, 'BoundingBox');
>> imshow(walk);
>> hold on; 
>> rectangle('Position', s.BoundingBox)
>> hold off;

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回答（2 个）

TADA 2021-9-5

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在 MATLAB Online 中打开

Without your image its hard to tell, but I tried your code on a couple matlab builtin images and it seems to work.

if you get an error, you may have more than one bounding box returned from regionprops, then you can use a loop to plot all rectangles

imshow(walk);
hold on; 
for i = 1:numel(s)
    rectangle('Position', s(i).BoundingBox)
end
hold off;

if you don't get an error, but just can't see the rectangle, it may be actually drawn around the entire image. It might happen if the contrast isn't high enough.

in that case, you can try lowering the cutoff intensity you use for im2bw.

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TADA 2021-9-5

Maybe it's not necessary, it was copied from the loop above

Andrew Killian 2021-9-5

Ok so it works but it's drawing the bounding box around the border/frame of the whole entire image, and not the object of the human walking in the middle of the image.

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