我正在使用python中的opencv和deepface模型制作一个人脸认证程序

Question

我写了这个函数，但有时会给我这个错误

"Authenticated as Muhammad Zair
[ WARN:[email protected]] global cap_msmf.cpp:1768 CvCapture_MSMF::grabFrame videoio(MSMF): can't grab frame. Error: -2147483638
Deleting the database object"

这是函数：

@staticmethod
    def authenticate_user(users):
        video = cv2.VideoCapture(0)
        start_time = time.time()
        capture = False
        frame = None
        flag = False

        def video_thread():
            nonlocal capture, frame
            while not flag:
                capture, frame = video.read()
                if not capture:
                    continue
        
        def video_show():
            while not flag:
                if frame is not None:
                    cv2.imshow("the video", frame)
                    cv2.waitKey(1) 
        
        capture_thread1 = threading.Thread(target=video_thread)
        capture_thread1.start()

        capture_thread2 = threading.Thread(target = video_show)
        capture_thread2.start()

        while time.time() - start_time < 20 and not flag:
            if capture:
                for user in users:
                    user_id, user_name, user_type, image_path = user
                    registered_image = cv2.imread(image_path)
                    result = DeepFace.verify(frame, registered_image, model_name='VGG-Face', enforce_detection=False)
                    if result['verified']:
                        print(f"Authenticated as {user_name}")
                        flag = True
                        break
        video.release()
        cv2.destroyAllWindows()

        if flag:
            return user_type                
        print("Failed to authenticate ")
        sys.exit()

本以为人脸认证后程序能正常运行并退出该功能。但它在终端中给出错误警告，它不会终止程序，但我想解决它。

Answer 1

您正在从capture_thread1读取视频，因此需要在线程中释放它。否则，线程将尝试读取已经发布的视频。

此外，您需要销毁 capture_thread2 中的窗口。

拥有一个可以在使用线程时触发的停止命令也会很有帮助。我用你的旗帜做了它，你可以看到下面的例子：

import cv2
import time
import threading
import sys
from deepface import DeepFace

def authenticate_user():
        video = cv2.VideoCapture(0)
        start_time = time.time()
        capture = False
        frame = None
        flag = False

        def video_thread(arg):
            nonlocal capture, frame
            capture_thread1 = threading.currentThread()
            while getattr(capture_thread1, "flag", True):
                capture, frame = video.read(2)
                if not capture:
                    continue
            video.release()
        
        def video_show(arg):
            capture_thread2 = threading.currentThread()
            while getattr(capture_thread2, "flag", True):
                if frame is not None:
                    cv2.imshow("the video", frame)
                    cv2.waitKey(1) 
            cv2.destroyAllWindows()
        
        capture_thread1 = threading.Thread(target=video_thread, args=("task",))
        capture_thread1.start()

        capture_thread2 = threading.Thread(target = video_show, args=("task",))
        capture_thread2.start()

        while time.time() - start_time < 20 and not flag:
            if capture:
                registered_image = cv2.imread("./my_img.jpg")#try with your path!!!
                result = DeepFace.verify(frame, registered_image, model_name='VGG-Face', enforce_detection=False)
                if result['verified']:
                    print(f"Authenticated as you")
                    capture_thread1.flag = False
                    capture_thread2.flag = False
                    break
        

        if capture_thread1.flag == False:
            return 1                
        print("Failed to authenticate ")
        sys.exit()

authenticate_user()