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Getting Rid of Nested For Loops

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Jacob Mevorach
Jacob Mevorach 2017-3-30
评论： Jacob Mevorach 2017-4-5
So I have a bunch of nested for loops in the following code but I feel like there has to be a faster and better way to eliminate these things so it will run faster. If anyone had some insight into how I might do this I would be greatly appreciative.
function [mask] = bbox_analysis(bboxes, mask, blackwhiteframe, th, fractional_th)
% Cycle through every bbox in the frame
bbox_dim = size(bboxes);
for b = 1:bbox_dim(1)
x_1 = bboxes(b, 1);
y_1 = bboxes(b, 2);
x_2 = x_1 + bboxes(b, 3);
y_2 = y_1 + bboxes(b, 4);
cropped_image = imcrop(blackwhiteframe, [x_1, y_1, bboxes(b, 3), bboxes(b, 4)]); % Section of frame captured in bbox
max_image = max(cropped_image);
threshold = max(th/255, max_image*fractional_th);
new_image = (cropped_image > threshold);
for i = x_1:x_2-1
for j = y_1:y_2-1
mask(j, i) = new_image(j+1-y_1, i+1-x_1);
end
end
end
end
  2 个评论
Matt J
Matt J 2017-3-30
Are you sure you don't mean
max_image = max(cropped_image(:));
Jacob Mevorach
Jacob Mevorach 2017-3-31
You're right I do! Thanks for letting me know.

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采纳的回答

Jan
Jan 2017-4-3
Replace
for i = x_1:x_2-1
for j = y_1:y_2-1
mask(j, i) = new_image(j+1-y_1, i+1-x_1);
end
end
by
mask(y_1:y_2-1, x_1:x_2-1) = new_image((y_1+1-y_1):(y_2-1+1-y_1), (x_1+1-x_1):(x_2-1+1-x_1));
  3 个评论
显示 1更早的评论
Matt J
Matt J 2017-4-5
编辑：Matt J 2017-4-5
The above should simplify to
mask(y_1:y_2-1, x_1:x_2-1) = new_image;

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