When working with OpenCV video capture, but when you only occasionally use images, you will get older images from the capture buffer.
This code example solves this issue by running a separate capture thread that continually saves images to a temporary buffer.
Therefore, you can always get the latest image from the buffer. The code is based on our basic example How to take a webcam picture using OpenCV in Python
video_capture = cv2.VideoCapture(0)
video_capture.set(cv2.CAP_PROP_FRAME_WIDTH, 1920)
video_capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080)
if not video_capture.isOpened():
raise Exception("Could not open video device")
class TakeCameraLatestPictureThread(threading.Thread):
def __init__(self, camera):
self.camera = camera
self.frame = None
super().__init__()
# Start thread
self.start()
def run(self):
while True:
ret, self.frame = self.camera.read()
latest_picture = TakeCameraLatestPictureThread(video_capture)Usage example:
# Convert latest image to the correct colorspace rgb_img = cv2.cvtColor(latest_picture.frame, cv2.COLOR_BGR2RGB) # Show plt.imshow(rgb_img)