如何计算在直播相机中使用帧的非零像素数？它与图像一起工作，但在帧中不起作用。我在用opencv

Question

import cv2
import pickle
import cvzone
import numpy as np

#video feed
cap = cv2.VideoCapture(0)


with open("CarParkPos", "rb") as f:
    posList = pickle.load(f)

width, height = 100, 50

def checkParkingSpace(frameProcess):
    for pos in posList:
        x,y = pos

        frameCrop = frame[y:y+height, x:x+width]
        cv2.imshow(str(x*y), frameCrop)
        count = cv2.countNonZero(frameCrop)
        cvzone.putTextRect(frame, "asd", (x,y+height-3), scale = 1, thickness=2, offset=0)

cv2.countNonZero在实时摄像机中计数像素时似乎不起作用，但在使用视频文件时工作得很好。

#converted rgb camera to black and white
while True:
    ret, frame = cap.read()
    frameGray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    frameBlur = cv2.GaussianBlur(frameGray, (3,3), 1)
    frameThreshold = cv2.adaptiveThreshold(frameBlur, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
                                           cv2.THRESH_BINARY_INV, 25, 16)
    frameMedian = cv2.medianBlur(frameThreshold,5)
    kernel = np.ones((1,1), np.uint8)
    frameDilate = cv2.dilate(frameMedian,kernel, iterations = 1)

    checkParkingSpace(frameDilate)
    
    #writing the rectangle shapes in camera
    for pos in posList:
        cv2.rectangle(frame, pos, (pos[0] + width, pos[1] + height), (0, 200, 0), 2)

    cv2.imshow("Frame", frame)
    cv2.waitKey(1)

我不完全理解所有的代码，因为我刚刚看了一个教程。我想要做的正是视频https://www.youtube.com/watch?v=caKnQlCMIYI中的那个，但是我不想使用视频文件，而是想使用一个实时摄像头。

Answer 1

for pos in posList:
    x,y = pos

    frameCrop = frame[y:y+height, x:x+width]
    cv2.imshow(str(x*y), frameCrop)
    count = cv2.countNonZero(cv2.Canny(frameCrop, 100, 200))
    cvzone.putTextRect(frame, str(count), (x,y+height-3), scale = 1, thickness=2, offset=0)

我做的是精明的帧，然后计数非黑色像素。