错误：在 Python 中同时打开两个摄像头 - OPENCV (Pycharm) - 错误 (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'

Question

快乐的一天，我正在尝试同步两个摄像头 （我的本地计算机）和带有 IP 网络摄像头的手机摄像头， 但是，在运行代码时会产生错误，并且这两个 我之前打开的相机已关闭（见照片）。什么 这是由于？感谢您的帮助！

错误 -->

Traceback (most recent call last):
   File "C:\Users\JUCABALL\Desktop\camera_stream_openCV-master\main.py", line 20, in <module>
     cv2.imshow ('cam1', frame1)
cv2.error: OpenCV (4.5.4-dev) D:\a\opencv-python\opencv-python\opencv\modules\imgproc\src\color.cpp: 182:
error: (-215: Assertion failed)! _src .empty () in function 'cv :: cvtColor'

这是标签页 - 几秒钟后标签页关闭

[标签，2 个摄像头][1]

这是我的代码

import numpy as np
import cv2


# capture the webcam
vid1 = cv2.VideoCapture(0, cv2.CAP_DSHOW)
vid2 = cv2.VideoCapture(1, cv2.CAP_DSHOW)
vid3 = cv2.VideoCapture(
    "http://192.168.0.11:8080/video", cv2.CAP_DSHOW
)  # ipwebcam address


while True:  # while true, read the camera
    ret, frame = vid1.read()
    ret1, frame1 = vid2.read()
    ret2, frame2 = vid3.read()

    if ret:
        cv2.imshow("cam0", frame)  # frame with name and variable of the camera
        cv2.imshow("cam1", frame1)
        cv2.imshow("cam3", frame2)

    # to break the loop and terminate the program
    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

vid1.release()
vid2.release()
vid3.release()

Answer 1

问题是您没有检查ret1 和ret2 的值。

如果是False，图像将不会被捕获，而您仍在尝试显示它们，OpenCV 会崩溃，因为无法显示不存在的图像。

试试

if ret:
    cv2.imshow("cam0", frame)
if ret1:
    cv2.imshow("cam1", frame1)
if ret2:
    cv2.imshow("cam3", frame2)  

改为。

您还可以将所有捕获设备存储在一个列表中，并且所有捕获的图像同样如此，以使代码更易于使用：

import numpy as np
import cv2

captures = [
    cv2.VideoCapture(0, cv2.CAP_DSHOW),
    cv2.VideoCapture(1, cv2.CAP_DSHOW),
    cv2.VideoCapture("http://192.168.0.11:8080/video", cv2.CAP_DSHOW),  # ipwebcam address
]


while True:  # while true, read the camera
    frames = []
    for cap in captures:
        ret, frame = cap.read()
        frames.append((frame if ret else None))

    for i, frame in enumerate(frames):
        if frame is not None:  # None if not captured
            cv2.imshow(f"cam{i}", frame)

    # to break the loop and terminate the program
    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

for cap in captures:
    cap.release()