使用PyQt4进行OpenCV视频捕获

Question

我一直在尝试使用PyQt4 GUI和OpenCV捕获视频。我创建了一些按钮，如“开始”，“结束”等来控制捕捉。开始很好，但我无法停止捕获。要停止捕获，我需要打破startCapture（）函数下面的while循环，我无法实现它。

目前，endCapture（）破坏了窗口，但startCapturewhile循环简单地创建它，继续捕捉。唯一的选择是打破这个循环。

下面是我使用的代码：

import cv2 
import numpy as np 
from PyQt4 import QtGui, QtCore 

def startCapture(cap): 
    print "pressed start" 
    while(True): 
     ret, frame = cap.read() 
     cv2.imshow("Capture", frame) 
     cv2.waitKey(5) 
    cv2.destroyAllWindows() 

def endCapture(cap): 
    print "pressed End" 
    cv2.destroyAllWindows() 

def quitCapture(cap): 
    print "pressed Quit" 
    cv2.destroyAllWindows() 
    cap.release() 
    QtCore.QCoreApplication.quit() 

class Window(QtGui.QWidget): 
    def __init__(self): 

     c = cv2.VideoCapture(0) 

     QtGui.QWidget.__init__(self) 
     self.setWindowTitle('Control Panel') 

     self.start_button = QtGui.QPushButton('Start',self) 
     self.start_button.clicked.connect(lambda : startCapture(c, True)) 

     self.end_button = QtGui.QPushButton('End',self) 
     self.end_button.clicked.connect(lambda : endCapture(c)) 

     self.quit_button = QtGui.QPushButton('Quit',self) 
     self.quit_button.clicked.connect(lambda : quit(c)) 

     vbox = QtGui.QVBoxLayout(self) 
     vbox.addWidget(self.start_button) 
     vbox.addWidget(self.end_button) 
     vbox.addWidget(self.quit_button) 

     self.setLayout(vbox) 
     self.setGeometry(100,100,200,200) 
     self.show() 

if __name__ == '__main__': 

    import sys 
    app = QtGui.QApplication(sys.argv) 
    window = Window() 
    sys.exit(app.exec_()) 

任何一个可以建议如何打破这一循环，并退出捕捉？

Answer 1

class Capture(): 
    def __init__(self): 
     self.capturing = False 
     self.c = cv2.VideoCapture(0) 

    def startCapture(self): 
     print "pressed start" 
     self.capturing = True 
     cap = self.c 
     while(self.capturing): 
      ret, frame = cap.read() 
      cv2.imshow("Capture", frame) 
      cv2.waitKey(5) 
     cv2.destroyAllWindows() 

    def endCapture(self): 
     print "pressed End" 
     self.capturing = False 
     # cv2.destroyAllWindows() 

    def quitCapture(self): 
     print "pressed Quit" 
     cap = self.c 
     cv2.destroyAllWindows() 
     cap.release() 
     QtCore.QCoreApplication.quit() 

在窗口：

self.capture = Capture() 
self.start_button = QtGui.QPushButton('Start',self) 
self.start_button.clicked.connect(self.capture.startCapture) 

self.end_button = QtGui.QPushButton('End',self) 
self.end_button.clicked.connect(self.capture.endCapture) 

self.quit_button = QtGui.QPushButton('Quit',self) 
self.quit_button.clicked.connect(self.capture.quitCapture) 

Answer 2

上面的答案是伟大的，但对于像我这样的初学者很难看到“在窗口”的部分应该如何的原代码多少应该保持。以下是基于以上信息的完整工作代码：

import cv2 
from PyQt4 import QtGui, QtCore 


class Capture(): 
    def __init__(self): 
     self.capturing = False 
     self.c = cv2.VideoCapture(0) 

    def startCapture(self): 
     print "pressed start" 
     self.capturing = True 
     cap = self.c 
     while(self.capturing): 
      ret, frame = cap.read() 
      cv2.imshow("Capture", frame) 
      cv2.waitKey(5) 
     cv2.destroyAllWindows() 

    def endCapture(self): 
     print "pressed End" 
     self.capturing = False 

    def quitCapture(self): 
     print "pressed Quit" 
     cap = self.c 
     cv2.destroyAllWindows() 
     cap.release() 
     QtCore.QCoreApplication.quit() 


class Window(QtGui.QWidget): 
    def __init__(self): 

     QtGui.QWidget.__init__(self) 
     self.setWindowTitle('Control Panel') 

     self.capture = Capture() 
     self.start_button = QtGui.QPushButton('Start',self) 
     self.start_button.clicked.connect(self.capture.startCapture) 

     self.end_button = QtGui.QPushButton('End',self) 
     self.end_button.clicked.connect(self.capture.endCapture) 

     self.quit_button = QtGui.QPushButton('Quit',self) 
     self.quit_button.clicked.connect(self.capture.quitCapture) 

     vbox = QtGui.QVBoxLayout(self) 
     vbox.addWidget(self.start_button) 
     vbox.addWidget(self.end_button) 
     vbox.addWidget(self.quit_button) 

     self.setLayout(vbox) 
     self.setGeometry(100,100,200,200) 
     self.show() 


if __name__ == '__main__': 
    import sys 
    app = QtGui.QApplication(sys.argv) 
    window = Window() 
    sys.exit(app.exec_())