人脸检测算法的cv2问题

Question

我有一个面部检测程序。 我试着运行代码，但不起作用

import cv2
import numpy as np

recognizer = cv2.face.LBPHFaceRecognizer_create()
recognizer.read("trainer/trainer.yml")
cascadePath = "haarcascade_frontalface_default.xml"
faceCascade = cv2.CascadeClassifier(cascadePath);


cam = cv2.VideoCapture(0)
fontFace = cv2.FONT_HERSHEY_SIMPLEX
fontScale = 1
fontColor = (255, 255, 255)
while True:
    ret, im =cam.read()
    gray=cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
    faces=faceCascade.detectMultiScale(gray, 1.2,5)
    for(x,y,w,h) in faces:
        cv2.rectangle(im,(x,y),(x+w,y+h),(225,0,0),2)

        Id, conf = recognizer.predict(gray[y:y+h,x:x+w])
        if(conf<50):
            if(Id==1):
                Id="chandra"
            elif(Id==2):
                Id="vamsi"

        else:
            Id="Unknown"
        cv2.putText(im,str(Id), (x,y+h),fontFace, 255)
    cv2.imshow('im',im) 
    if (cv2.waitKey(10) == ord('q')):
        break
cam.release()
cv2.destroyAllWindows()

我有个错误：

(-215:Assertion failed) !empty() in function 'cv::CascadeClassifier::detectMultiScale'

我正在使用opencv2和python3.7

Answer 1

请使用下面的代码检查您的相机是否有图像：

import numpy as np
import cv2

cap = cv2.VideoCapture(0)

while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()

    # Our operations on the frame come here
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Display the resulting frame
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()

Answer 2

也许这会有帮助：

try:
    ret, im =cam.read()
except:
    continue