Question

尝试链接PyQt和Opencv视频源，无法理解如何应用while循环来连续流式传输视频。它只是拍摄一张照片。请任何人都可以帮忙解决问题。

PtQt = 5
的Python = 3.6.1

class App(QWidget):
    def __init__(self):
        super().__init__()
        self.title = 'PyQt5 Video'
        self.left = 100
        self.top = 100
        self.width = 640
        self.height = 480
        self.initUI()


    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
        self.resize(1800, 1200)
        #create a label
        label = QLabel(self)
        cap = cv2.VideoCapture(0)
        ret, frame = cap.read()
        rgbImage = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        convertToQtFormat = QtGui.QImage(rgbImage.data, rgbImage.shape[1], rgbImage.shape[0],
                                         QtGui.QImage.Format_RGB888)
        convertToQtFormat = QtGui.QPixmap.fromImage(convertToQtFormat)
        pixmap = QPixmap(convertToQtFormat)
        resizeImage = pixmap.scaled(640, 480, QtCore.Qt.KeepAspectRatio)
        QApplication.processEvents()
        label.setPixmap(resizeImage)
        self.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())

Answer 1

问题是获取图像的功能只执行一次而不更新标签正确的方法是将它放在循环中，但它会导致阻塞主窗口。可以使用QThread类来解决主窗口的阻塞问题，并通过信号QImage发送以更新标签。例如：

class Thread(QThread):
    changePixmap = pyqtSignal(QImage)

    def run(self):
        cap = cv2.VideoCapture(0)
        while True:
            ret, frame = cap.read()
            if ret:
                # https://stackoverflow.com/a/55468544/6622587
                rgbImage = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
                h, w, ch = rgbImage.shape
                bytesPerLine = ch * w
                convertToQtFormat = QtGui.QImage(rgbImage.data, w, h, bytesPerLine, QtGui.QImage.Format_RGB888)
                p = convertToQtFormat.scaled(640, 480, Qt.KeepAspectRatio)
                self.changePixmap.emit(p)


class App(QWidget):
    def __init__(self):
        super().__init__()
        [...]
        self.initUI()

    @pyqtSlot(QImage)
    def setImage(self, image):
        self.label.setPixmap(QPixmap.fromImage(image))

    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
        self.resize(1800, 1200)
        # create a label
        self.label = QLabel(self)
        self.label.move(280, 120)
        self.label.resize(640, 480)
        th = Thread(self)
        th.changePixmap.connect(self.setImage)
        th.start()

Answer 2

为PySide2和qimage2ndarray更新此

from PySide2.QtCore import *
from PySide2.QtGui import *
import cv2 # OpenCV
import qimage2ndarray # for a memory leak,see gist
import sys # for exiting

# Minimal implementation...

def displayFrame():
    ret, frame = cap.read()
    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
    image = qimage2ndarray.array2qimage(frame)
    label.setPixmap(QPixmap.fromImage(image))

app = QApplication([])
window = QWidget()

# OPENCV

cap = cv2.VideoCapture(0)
cap.set(cv2.CAP_PROP_FRAME_WIDTH, 320)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 240)

# timer for getting frames

timer = QTimer()
timer.timeout.connect(displayFrame)
timer.start(60)
label = QLabel('No Camera Feed')
button = QPushButton("Quiter")
button.clicked.connect(sys.exit) # quiter button 
layout = QVBoxLayout()
layout.addWidget(button)
layout.addWidget(label)
window.setLayout(layout)
window.show()
app.exec_()

# See also: https://gist.github.com/bsdnoobz/8464000

Answer 3

感谢Taimur Islam的提问。感谢eyllanesc的精彩回答，我对你的代码进行了一些修改。我使用PtQt = 4 Python = 2.7而我没有使用opencv

import sys    
import numpy as np
import flycapture2 as fc2

from PyQt4.QtCore import (QThread, Qt, pyqtSignal)
from PyQt4.QtGui import (QPixmap, QImage, QApplication, QWidget, QLabel)

class Thread(QThread):
    changePixmap = pyqtSignal(QImage)

    def __init__(self, parent=None):
        QThread.__init__(self, parent=parent)       
        self.cameraSettings()


    def run(self):      
        while True:
            im = fc2.Image()
            self.c.retrieve_buffer(im)
            a = np.array(im)    

            rawImage = QImage(a.data, a.shape[1], a.shape[0], QImage.Format_Indexed8)

            self.changePixmap.emit(rawImage)

    def cameraSettings(self):
        print(fc2.get_library_version())
        self.c = fc2.Context()
        numberCam = self.c.get_num_of_cameras()
        print(numberCam)    
        self.c.connect(*self.c.get_camera_from_index(0))
        print(self.c.get_camera_info())
        m, f = self.c.get_video_mode_and_frame_rate()
        print(m, f)
        print(self.c.get_property_info(fc2.FRAME_RATE))
        p = self.c.get_property(fc2.FRAME_RATE)
        print(p)
        self.c.set_property(**p)
        self.c.start_capture()


class App(QWidget):
    def __init__(self):
            super(App,self).__init__()
            self.title = 'PyQt4 Video'
            self.left = 100
            self.top = 100
            self.width = 640
            self.height = 480
            self.initUI()

    def initUI(self):
            self.setWindowTitle(self.title)
            self.setGeometry(self.left, self.top, self.width, self.height)
            self.resize(800, 600)
            # create a label
            self.label = QLabel(self)
            self.label.move(0, 0)
            self.label.resize(640, 480)
            th = Thread(self)
            th.changePixmap.connect(lambda p: self.setPixMap(p))
            th.start()

    def setPixMap(self, p):     
        p = QPixmap.fromImage(p)    
        p = p.scaled(640, 480, Qt.KeepAspectRatio)
        self.label.setPixmap(p)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    ex.show()
    sys.exit(app.exec_())

PyQt显示来自opencv的视频流

3 个答案: