Hi, I have doubts regarding how the co ordinates of ROI are selected . For example in the below code snippet
//Code Snippet in Python
ret , img =cap.read() # video is gettiing read
gray = cv2.cvtColor(img , cv2.COLOR_BGR2GRAY) ## gray contains the pixel density not the coordinates of each pixel
3.frontal_face= frontalface_cascade.detectMultiScale(gray,1.3,5)
for (x, y, w, h) in frontal_face: # x,y are coordinates not the pixel density
cv2.rectangle(gray, (x, y), (x+w, y+h), (255, 0, 0), 2)
//how we are slicing array having pixel densities to get the coordinates of part of a face? 5.roi_mouth=gray[y:y+h,x:x+w]
//Code Snippet Ends
I am not getting in line 5. how the array called "gray" which stores pixel densities is sliced to get coordinates of part of face .
Please suggest.