Unable to see and take the picture in second time

edit

video_capture = cv2.VideoCapture(0)
count = 0

while True:

  print('oi')
  ret, frame = video_capture.read()
  small_frame = cv2.resize(frame, (0,0), fx=0.25, fy=0.25)

  rgb_small_frame = small_frame [:,:,::-1]

  face_locations = face_recognition.face_locations(rgb_small_frame)
  face_encodings = face_recognition.face_encodings(rgb_small_frame, face_locations)

  face_labels = []
  for face_location, face_encoding in zip(face_locations, face_encodings):
    metadata = lookup_known_face(face_encoding, know_face_encodings, know_face_metadata)
    if metadata is not None:
      video_capture.release()
      cv2.destroyAllWindows()
      cv2.waitKey(10)
      return Response(metadata)

    else:
      return Response(False)
  cv2.imshow('Video', frame)
  key = cv2.waitKey(1)


  if count == 5:

    video_capture.release()
    cv2.waitKey(0)
    cv2.destroyAllWindows()
    cv2.waitKey(1)
    return Response(False)

Had the same issue and cant solve it out, this is a signup script which works propoerly at the first time that i call it from my interface, but at a second time it just doesn't work at all. Any ideas @supra56

I noticed that you left out semi-colon in line 3. Also your're missing Trap/except. When you click button s, you didn't called method method_webcam_trigger(). As @berak said, by removing release was wrong. I also added waitKey for 10 seconds. But remember, by clicking button s, you saved filename saved_img.jpg. When you clicking buitton again, it asking you to save as. So click filename, you will add index...saved_img1.jpg, and so on.

#!/usr/bin/env python37
#Raspberry pi 3/4, OpenCV 4.1.2
#Date: December 2nd, 2019

import cv2

def method_webcam_trigger():
    key = cv2. waitKey(10)
    webcam = cv2.VideoCapture(0)
    while True:
        try:
            check, frame = webcam.read()
            cv2.imshow("Capturing", frame)
            key = cv2.waitKey(1)
            if key == ord('s'): 
                cv2.imwrite(filename='saved_img.jpg', img=frame)
                print("Image saved!")
                webcam.release()
                cv2.destroyAllWindows()
                cv2.waitKey(10)
                method_webcam_trigger()
                webcam.release()
                cv2.destroyAllWindows()
                cv2.waitKey(10)               
                break                
            elif key == ord('q'):                 
                webcam.release()
                cv2.destroyAllWindows()
                break 
        except:
              pass

method_webcam_trigger()

You destroy your camera when you save the image so obviously getting the bext frame fails.