--- a
+++ b/combinedDeepLearningActiveContour/functions/mask2subImage.m
@@ -0,0 +1,37 @@
+% this function takes a mask, an image I, and a size M, and extracts an M*M
+% sub-image I_sub centered at cnt.
+
+function [I_sub,cnt]=mask2subImage(I,mask,M)
+% inputs
+% I : original image
+% mask : mask should be the same size of the original image
+% M : size of ROI
+
+% output
+% I_sub : sub image centered at cnt
+% cnt : ceneter of the sub-image respect to the original image
+
+% find the center of the mask
+temp=regionprops(mask, 'Centroid');
+cnt1=temp.Centroid;
+%cnt=floor(cnt1);
+cnt=round(cnt1);
+
+
+% coordinates of the top and bottom corners
+cnt_x=cnt(1);
+cnt_y=cnt(2);
+
+% top left corner
+x1=cnt_x-M/2;
+y1=cnt_y-M/2;
+
+% bottom right corner
+x4=cnt_x+M/2-1;
+y4=cnt_y+M/2-1;
+
+% extract the sub-image
+I_sub=I(y1:y4,x1:x4);
+
+
+end
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