Extract detected edges from image into separate image

Question

I would like to crop a certain region around a detected corner (e.g. detected with Harris Detector) and save this region as a separate image. Does anyone have an idea how to work this out?

I had the idea to start from this basic lines:

import cv2
import numpy as np

filename = 'pic1.jpg'
img = cv2.imread(filename)
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)

gray = np.float32(gray)
dst = cv2.cornerHarris(gray,2,3,0.04)

#result is dilated for marking the corners, not important
dst = cv2.dilate(dst,None)

# Threshold for an optimal value, it may vary depending on the image.
img[dst>0.01*dst.max()]=[0,0,255]

cv2.imwrite('pic2.jpg',img)
if cv2.waitKey(0) & 0xff == 27: cv2.destroyAllWindows()

Answer 1

Find contours in the edge image and get the bounding rectangle of that contour. Using this bounding rectangle details, crop the image. You will have the desired output.