pyqt5调用usb摄像头

可以使用OpenCV库和PyQt5来调用USB摄像头。首先，你需要安装OpenCV和PyQt5库。然后，你可以使用OpenCV的VideoCapture函数来获取摄像头的图像。接下来，你可以将图像显示在PyQt5的GUI界面上。

这是一个使用PyQt5调用USB摄像头的简单示例代码：

import sys
import cv2
from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtGui import QImage, QPixmap
from PyQt5.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget

class Webcam(QWidget):
    def __init__(self):
        super().__init__()

        self.label = QLabel(self)
        self.image = None

        self.timer = QTimer()
        self.timer.timeout.connect(self.update_frame)
        self.timer.start(10)

        layout = QVBoxLayout()
        layout.addWidget(self.label)
        self.setLayout(layout)

    def update_frame(self):
        ret, frame = self.cap.read()
        if ret:
            self.image = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
            h, w, ch = self.image.shape
            bytes_per_line = ch * w
            q_image = QImage(self.image.data, w, h, bytes_per_line, QImage.Format_RGB888)
            self.label.setPixmap(QPixmap.fromImage(q_image))
        else:
            self.timer.stop()

    def start_camera(self, device=0):
        self.cap = cv2.VideoCapture(device)

    def closeEvent(self, event):
        self.cap.release()
        super().closeEvent(event)

if __name__ == '__main__':
    app = QApplication(sys.argv)

    webcam = Webcam()
    webcam.start_camera()

    webcam.show()

    sys.exit(app.exec_())