“[WARN:0] `anonymous-namespace'::SourceReaderCB::~SourceReaderCB terminating async callback” 运行代码时出错

Question

我正在尝试运行此 OpenCV 代码以使用我的摄像机检测人脸。每当我运行我的代码时，它都会给我这个错误。我的摄像机上的灯闪烁，但随后关闭，控制台框中出现此错误以及这个 cv2.error: OpenCV(4.5.1) error: (-215:Assertion failed) !empty() in function 'cv::CascadeClassifier::detectMultiScale'

这是代码

# Load the cascade
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')

# To capture video from webcam.
cap = cv2.VideoCapture(0)
# To use a video file as input
# cap = cv2.VideoCapture('filename.mp4')

while True:
    # Read the frame
    _, img = cap.read()

    # Convert to grayscale
    #THIS IS THE ERROR AREA
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

    # Detect the faces
    faces = face_cascade.detectMultiScale(gray, 1.1, 4)

    # Draw the rectangle around each face
    for (x, y, w, h) in faces:
        cv2.rectangle(img, (x, y), (x + w, y + h), (255, 0, 0), 2)

    # Display
    cv2.imshow('img', img)

    # Stop if escape key is pressed
    k = cv2.waitKey(30) & 0xff
    if k == 27:
        break

# Release the VideoCapture object
cap.release()

Answer 1

由于相对路径，您的脚本似乎无法正确找到 haarcascade_frontalface_default.xml 文件。尝试给出绝对路径并检查。