Canny边缘检测：尝试只生成白线，视频上没有黑色背景

Question

我正在做一个项目，我将让一个摄像头使用Canny边缘检测来检测物体的边缘。然而，对于这个项目，我必须使黑色背景（见图）透明，在相机的原始黑白画面上播放。我该怎么办？注意：在黑暗中

black and white shot of a calendar(left), canny(right)

下面是我使用的代码

import cv2
import numpy as np
cap = cv2.VideoCapture(0)
while(True):
   #Captures video, frame-by-frame
   _, frame = cap.read()
   frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
   blurred_frame = cv2.GaussianBlur(frame, (5,5),0)


   canny1 = cv2.Canny(blurred_frame, 15, 20)
   #Displays the output.
   cv2.imshow("Frame", frame)
   cv2.imshow("Canny1", canny1)
#Press Q to stop loop, then proceed to end program as shown below.
   key = cv2.waitKey(1)
   if key == ord('q'):
      break
#End Program
cap.release()
cv2.destroyAllWindows()

提前谢谢

Answer 1

canny1 = cv2.bitwise_or(frame, canny1)