【Pyqt5用按钮控制QLabel打开摄像头】_designer 显示电脑摄像头

Pyqt5用按钮控制QLabel打开摄像头

界面设计

界面设计部分主要采用Qtdesigner快速设计，安装Qtdesigner和pyuic工具可参考转载文章： PyQt5+QtDesigner编写摄像头界面程序（一）——pyqt5、qtdesigner安装和环境设置
安装好Qtdesigner后打开，选择左侧组建栏中的QLabel用来显示视频、Push Button设计两个按钮，然后在右上方修改对应的名称，如下图所示，

设计完成后保存，会自动生成camera_ui.ui文件，再通过pyuic外部工具生成对应的camera_ui.py:

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'camera_ui.ui'
#
# Created by: PyQt5 UI code generator 5.9.2
#
# WARNING! All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 715)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.camera_label = QtWidgets.QLabel(self.centralwidget)
        self.camera_label.setGeometry(QtCore.QRect(90, 70, 591, 451))
        self.camera_label.setStyleSheet("border:5px solid black;\n"
"background-color: rgb(255, 255, 255);\n"
"")
        self.camera_label.setText("")
        self.camera_label.setObjectName("camera_label")
        self.start_camera = QtWidgets.QPushButton(self.centralwidget)
        self.start_camera.setGeometry(QtCore.QRect(140, 540, 93, 28))
        self.start_camera.setStyleSheet("background-color: rgb(255, 0, 255);")
        self.start_camera.setObjectName("start_camera")
        self.stop_camera = QtWidgets.QPushButton(self.centralwidget)
        self.stop_camera.setGeometry(QtCore.QRect(460, 540, 93, 28))
        self.stop_camera.setStyleSheet("background-color: rgb(255, 0, 255);")
        self.stop_camera.setObjectName("stop_camera")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 26))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.start_camera.setText(_translate("MainWindow", "star"))
        self.stop_camera.setText(_translate("MainWindow", "stop"))
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调用摄像头部分

需要利用用到定时器，当按下开始按钮时，启动定时器，隔100ms刷新显示一次图像，按下停止，定时器失效

main.py文件

from camera_ui import Ui_MainWindow
import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QMessageBox
from PyQt5 import QtCore
from PyQt5.QtGui import QPixmap
import cv2
import qimage2ndarray

class CamShow(QMainWindow,Ui_MainWindow):
    '''初始化程序，继承由Qtdesigner设计的py文件，设置定时器'''
    def __init__(self,parent=None):
        super(CamShow,self).__init__(parent)
        self.setupUi(self)
        self.timer_camera = QtCore.QTimer()
        self.start()
        
    '''绑定槽函数'''
    def start(self):
        self.start_camera.clicked.connect(self.bnt_start)
        self.stop_camera.clicked.connect(self.bnt_stop)
        
    '''若点击开始按钮，调用摄像头，定时器开启'''
    def bnt_start(self):
        self.cap = cv2.VideoCapture(0)
        self.timer_camera.start(100)
        self.timer_camera.timeout.connect(self.show_camera)

    '''若点击停止按钮，定时器失效'''
    def bnt_stop(self):
        self.timer_camera.stop()

    '''首先通过摄像头获取的图像resize，由于cv2默认使用的是BGR编码，图像显示偏蓝色，
    需要通过cvtColor和qimage2ndarray.array2qimage转换一下'''
    def show_camera(self):
        ret, img = self.cap.read()
        self.img = cv2.resize(img, (640, 480), interpolation=cv2.INTER_CUBIC)
        self.img1 = cv2.cvtColor(self.img, cv2.COLOR_BGR2RGB)
        qimg = qimage2ndarray.array2qimage(self.img)
        self.camera_label.setPixmap(QPixmap(qimg))
        self.camera_label.show()

    '''设计是否退出程序，防止误碰'''
    def closeEvent(self, event):
        reply = QMessageBox.question(self, '退出', "是否要退出该界面？",
                                     QMessageBox.Yes | QMessageBox.No, QMessageBox.No)
        if reply == QMessageBox.Yes:
            self.close()
            event.accept()
        else:
            event.ignore()

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

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