如何在matlab代码中裁剪图像中的矩形框

Question

I want to crop a detected faces in my code. Here is my code.

function DisplayDetections(im, dets)

imshow(im);

k = size(dets,1);

hold on;
for i=1:k
   rectangle('Position', dets(i,:),'LineWidth',2,'EdgeColor', 'r'); 

end
imcrop(rectangle);
hold off;

Their is syntax error in cropping. Can anybody help in cropping rectangle box detected in above box.

Answer 1

That code only draws the rectangles in your image. If you actually want to crop out portions of the image with the defined rectangles, use imcrop .

As such, you would do something like this to store all of your cropped rectangles. This is assuming that im and dets are already defined in your code from your function:

k = size(dets,1);
cropped = cell(1,k);

for i=1:k
   cropped{k} = imcrop(im, dets(i,:));
end

cropped would be a cell array where each element will store a cropped image defined by each rectangle within your dets array. This is assuming that dets is a 2D array where there are 4 columns, and the number of rows determines how many rectangles you have. Each row of dets should be structured like:

[xmin ymin width height] 

xmin , ymin are the horizontal and vertical co-ordinate of the top-left corner of the rectangle, and width and height are the width and height of the rectangle.

If you want to access a cropped portion in the cell array, simply do:

crp = cropped{k};

k would be the k ^th rectangle detected in your image.