所以我有一对夫妇的程序从去年的opencv所以我只是想尝试他们，但是，Opencv检测远程摄像头一样，DroidCam，但不能检测我的usb连接的相机，它的工作就好与相机应用程序在Windows上。我试图输入usb id，但它不工作。我试图重新启动我的笔记本电脑以为这是一个笔记本电脑的问题，但它不工作，所以我意识到它不能检测摄像头id 0和1。我不知道为什么，因为我记得去年我的摄像头在id# 0下工作得很好。这个程序是从12/14/2020开始的。下面是py中的代码：

import cv2
#############################################
frameWidth = 1500
frameHeight = 480
frontalFaceCascade = cv2.CascadeClassifier("file_location_and_name.xml")
FullBody = cv2.CascadeClassifier("file_location_and_name.xml")
minArea = 200
color = (255, 0, 255)
colour = (0, 255, 255)
colour2 = (0, 0, 255)
###############################################
cap = cv2.VideoCapture(0)
cap.set(3,  frameWidth)
cap.set(4,  frameHeight)
cap.set(10, 150)
count = 0
running = True
while running:
    ret, cam = cap.read()
    imgGray = cv2.cvtColor(cam, cv2.COLOR_BGR2GRAY)
    face = frontalFaceCascade.detectMultiScale(imgGray,  1.1,  10, cv2.CASCADE_FIND_BIGGEST_OBJECT)
    boy = FullBody.detectMultiScale(imgGray,  1.1,  10, cv2.CASCADE_DO_ROUGH_SEARCH)
    for (x,  y,  w,  h) in face:
        area = w*h
        if area > minArea:
            cv2.rectangle(cam, (x, y), (x + w, y + h), (255, 0, 255), 2)
            cv2.putText(cam, "Face", (x, y - 5), cv2.FONT_HERSHEY_COMPLEX_SMALL, 1, color, 2)
            imgRoi = cam[y:y + h, x:x + w]
            cv2.imshow("Result", cam)
            if cv2.waitKey(1) and 0xFF == ord('s'):
                cv2.imwrite("Resources/Scanned/NoPlate_"+str(count)+".jpg", imgRoi)
                cv2.rectangle(cam, (0, 200), (640, 300), (0, 255, 0), cv2.FILLED)
                cv2.putText(cam, "Scan Saved", (150, 265), cv2.FONT_HERSHEY_DUPLEX, 2, (0, 0, 255), 2)
                cv2.imshow("Result", cam)
                cv2.waitKey(500)
                count += 1
    for (x,  y,  w,  h) in boy:
        area = w*h
        if area > minArea:
            cv2.rectangle(cam, (x, y), (x + w, y + h), colour2, 2)
            cv2.putText(cam, "No mask", (x, y - 5), cv2.FONT_HERSHEY_COMPLEX_SMALL, 1, colour2, 2)
            imgRoi = cam[y:y + h, x:x + w]
            cv2.imshow("Result", cam)
            if cv2.waitKey(1) and 0xFF == ord('s'):
                cv2.imwrite("Resources/Scanned/NoPlate_"+str(count)+".jpg", imgRoi)
                cv2.rectangle(cam, (0, 200), (640, 300), (0, 255, 0), cv2.FILLED)
                cv2.putText(cam, "Scan Saved", (150, 265), cv2.FONT_HERSHEY_DUPLEX, 2, (0, 0, 255), 2)
                cv2.imshow("Result", cam)
                cv2.waitKey(500)
                count += 1

注意：我确实遵循了教程，并不声称这段代码是我的。