Implementation of a simple camera based on pyqt5

1、 First of all to ui Layout , The initialization interface is set with four buttons and a black background cloth , The four key function is set to turn on the camera 、 Turn off camera 、 Taking pictures 、 videotape , Pictured ：

open and close It's one of two , Click on open In the future, in addition to opening and displaying the camera screen , You have to close Key enable , hold open stop it

Click again close Will return to the black background , And turn off the open camera , Free the memory occupied by the camera , So that it can be opened next time

The two buttons can alternately control the camera to read , Memory occupation and release .
The implementation process is ：
self.openCameraBtn = QPushButton(‘open’) This is the setting named open The buttons
self.openCameraBtn.clicked.connect(self.openCamera) This is the function connection triggered after the setting key is pressed , That is, set the key open Press trigger openCamera Execution of a function .
self.openCameraBtn.setEnabled(True) This is to enable the key
self.openCameraBtn.setEnabled(False) This is to turn off the key

The camera image display here also involves the problem of timing refresh . So when the program is started, in addition to initialization UI It also initializes a timer ：

    def initTimer(self):
        self.timer = QTimer(self)# Import timer 
        self.timer.timeout.connect(self.show_pic)# Timeout refresh function self.show_pic
            
    def show_pic(self):
        ret, img = self.camera.read()
        if not ret:
            print('read error!\n')
            self.closeCamera()
            csbox = QMessageBox(QMessageBox.Warning, self.tr(" Read failed "), self.tr(" Camera open failed , Please check the connection ！"), QMessageBox.NoButton, self)
            csbox.exec_() 
            return
        # cv2.flip(img, 1, img)# Parameters ： original image , Flip type , New image   Flip type : level （ about ） Flip >0, vertical （ Up and down ） Flip =0, Flip horizontally and vertically <0
        frame = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        print(frame.shape)#(480, 640, 3)  Row number , Number of columns , Number of color channels ( namely RGB) img.shape[0] What you get is the height of the picture ,img.shape[1] The result is the width of the picture  
        heigt, width = frame.shape[:2]#[0] and [1]
        pixmap = QImage(frame, width, heigt, QImage.Format_RGB888)# Read images 
        # print(pixmap)
        pixmap = QPixmap.fromImage(pixmap)
        self.showcamera.setPixmap(pixmap)# Set pixel 
        
        self.imgsave=img
        
        if self.opencameras==True and self.openvideo==True:
            self.out.write(frame)
            self.videoCameraBtn.setEnabled(False)
        else:
            print(self.openvideo)
            self.openvideo=False
            self.videoCameraBtn.setEnabled(True)

2、 The next step is to set the photographing function , Press the Photo button to enter pictureCamera function , The function looks like this , It can be seen that there is detection to ensure that the camera is turned on before reading and writing image data , If you don't make sure the camera is on , Data is empty , An error will be reported when the graph is written , Make sure the camera is turned on before taking photos and videos .

        if self.opencameras==True:# The camera has been turned on 
            img_name = 'pictures/%d.jpg'%self.count
            cv2.imwrite(img_name, self.imgsave) # Training set write path 
            self.count += 1
            cv2.imshow("camera", self.imgsave)

You can see , After pressing the button to take pictures, the current camera status will be saved and written into a picture named in sequence , And a captured image will pop up .

3、 Here is how to set the video recording function , Press the video button to enter videoCamera function , The function looks like this , It can be seen that there is also detection to ensure that the camera is turned on before reading and writing image data .

        if self.opencameras==True:# The camera has been turned on 
            self.nowtimes = time.strftime("%Y-%m-%d_%H_%M_%S_%p",time.localtime())+"_"+time.strftime("%u",time.localtime())
            videos='./videos/'+self.nowtimes+'.avi'
            print(videos)
            self.out = cv2.VideoWriter(videos,self.fourcc, 20.0, (640,480))# Create a video file 
            self.openvideo=True # Open the tag of the video file 
            
            self.videoCameraBtn.setEnabled(False)

In addition to the normal process of creating video files , There is also a button to turn off video recording , This also means that only one video can be generated at a time avi file , Each time the image is refreshed regularly, it will be judged whether it is in the recording process , If it is in the video recording, read it from the camera frame Write to video file

        if self.opencameras==True and self.openvideo==True:
            self.out.write(frame)
            self.videoCameraBtn.setEnabled(False)
        else:
            print(self.openvideo)
            self.openvideo=False
            self.videoCameraBtn.setEnabled(True)

The following figure shows the process of video recording ：
To stop recording, press closs Just turn off the camera . The function to close the key connection is as follows ：

        self.camera.release()# Release the occupied camera 
        if self.openvideo==True:
            self.out.release()      
        self.openCameraBtn.setEnabled(True)
        self.closeCameraBtn.setEnabled(False)# Turn off key enable 
        self.videoCameraBtn.setEnabled(True)# Enable key 
        self.showcamera.setStyleSheet("background:black;")# Set the style ： The background is black 
        self.showcamera.setPixmap(QPixmap())# Set pixel 
        self.timer.stop()# The timer stops 
        self.opencameras=False
        self.openvideo=False

You can see that the function contains several parts , One is to handle the camera , Free the memory occupied by the camera ; The second one is the button ui Handle , Even if you can open the button and video button , Disable the camera button ; The third is clock processing , Stop timer , The purpose is to stop displaying the images acquired by the camera , If you don't stop, an error will be reported , Because the memory of the camera has been released , therefore , The content of the image refreshed by the clock cannot be collected , All will be wrong .

The following is the source code of the project ：

#!/usr/bin/python3
# -*- coding: utf-8 -*-

from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
import cv2
import sys
import os
import time

def chdir(path):
    #  Introduce modules 
    import os
    #  Remove the first space 
    path = path.strip()
    #  Remove the tail  \  Symbol 
    path = path.rstrip("\\")
    #  Determine if the path exists 
    #  There is  True
    #  non-existent  False
    isExists = os.path.exists(path)
    #  Judge the result 
    if not isExists:
        #  Create a directory if it doesn't exist 
        #  Create directory manipulation functions 
        print(path + '  directory does not exist ')
        return False
    else:
        #  Do not create if directory exists , And prompt that the directory already exists 
        print(path + '  directory already exists ')
        return True
 
# Read the list of backup files 
def read_filename(filePath):
    import os
    name = os.listdir(filePath)# obtain filepath List of files 
    print(name)
    return name

    
class Example(QWidget):
    def __init__(self):
        super().__init__()
        # Check and create folders 
        if chdir('pictures')==False:
            os.mkdir('pictures')
        if chdir('videos')==False:
            os.mkdir('videos')
            
        print(len(read_filename('pictures')))
        # self.fourcc = cv2.VideoWriter_fourcc(*'XVID')#FourCC  It's just one.  4  Bytecode , Used to determine the encoding format of video 
        self.fourcc = cv2.VideoWriter_fourcc(*'MJPG')
        
        self.nowtimes=' '
        self.opencameras=False
        self.openvideo=False
        self.count = int(len(read_filename('pictures')))
        self.initUI()
        self.initTimer()
        
    def initTimer(self):
        self.timer = QTimer(self)# Import timer 
        self.timer.timeout.connect(self.show_pic)# Timeout refresh function self.show_pic
            
    def show_pic(self):
        ret, img = self.camera.read()
        if not ret:
            print('read error!\n')
            self.closeCamera()
            csbox = QMessageBox(QMessageBox.Warning, self.tr(" Read failed "), self.tr(" Camera open failed , Please check the connection ！"), QMessageBox.NoButton, self)
            csbox.exec_() 
            return
        # cv2.flip(img, 1, img)# Parameters ： original image , Flip type , New image   Flip type : level （ about ） Flip >0, vertical （ Up and down ） Flip =0, Flip horizontally and vertically <0
        frame = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        print(frame.shape)#(480, 640, 3)  Row number , Number of columns , Number of color channels ( namely RGB) img.shape[0] What you get is the height of the picture ,img.shape[1] The result is the width of the picture  
        heigt, width = frame.shape[:2]#[0] and [1]
        pixmap = QImage(frame, width, heigt, QImage.Format_RGB888)# Read images 
        # print(pixmap)
        pixmap = QPixmap.fromImage(pixmap)
        self.showcamera.setPixmap(pixmap)# Set pixel 
        
        self.imgsave=img
        
        if self.opencameras==True and self.openvideo==True:
            self.out.write(frame)
            self.videoCameraBtn.setEnabled(False)
        else:
            print(self.openvideo)
            self.openvideo=False
            self.videoCameraBtn.setEnabled(True)
            
    def openCamera(self):
        self.showcamera.setEnabled(True)
        self.camera = cv2.VideoCapture(0) #'http://admin:[email protected]:8081'
        # self.camera = cv2.VideoCapture('http://admin:[email protected]:8081')
        self.openCameraBtn.setEnabled(False)# Close button 
        self.closeCameraBtn.setEnabled(True)# Enable key 
        self.timer.start(3)# timing 3  Start timing 
        self.opencameras=True
  
    def closeCamera(self):
        self.camera.release()# Release the occupied camera 
        if self.openvideo==True:
            self.out.release()      
        self.openCameraBtn.setEnabled(True)
        self.closeCameraBtn.setEnabled(False)# Turn off key enable 
        self.videoCameraBtn.setEnabled(True)# Enable key 
        self.showcamera.setStyleSheet("background:black;")# Set the style ： The background is black 
        self.showcamera.setPixmap(QPixmap())# Set pixel 
        self.timer.stop()# The timer stops 
        self.opencameras=False
        self.openvideo=False
        
    def pictureCamera(self):
        print('picture')
        if self.opencameras==True:# The camera has been turned on 
            img_name = 'pictures/%d.jpg'%self.count
            cv2.imwrite(img_name, self.imgsave) # Training set write path 
            self.count += 1
            cv2.imshow("camera", self.imgsave)
        
    def videoCamera(self):
        print('video')
        if self.opencameras==True:# The camera has been turned on 
            self.nowtimes = time.strftime("%Y-%m-%d_%H_%M_%S_%p",time.localtime())+"_"+time.strftime("%u",time.localtime())
            videos='./videos/'+self.nowtimes+'.avi'
            print(videos)
            self.out = cv2.VideoWriter(videos,self.fourcc, 20.0, (640,480))# Create a video file 
            self.openvideo=True # Open the tag of the video file 
            
            self.videoCameraBtn.setEnabled(False)
        
    def initUI(self):
        self.openCameraBtn = QPushButton('open')
        self.openCameraBtn.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)  # Set the control in the layout （layout） Inside the size change attribute  QSizePolicy.Fixed: Fixed size , Do not stretch or compress 
        self.openCameraBtn.clicked.connect(self.openCamera)
        
        self.closeCameraBtn = QPushButton('close')
        self.closeCameraBtn.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)
        self.closeCameraBtn.clicked.connect(self.closeCamera)
        
        self.pictureCameraBtn = QPushButton(' Taking pictures ')
        self.pictureCameraBtn.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)  # Set the control in the layout （layout） Inside the size change attribute  QSizePolicy.Fixed: Fixed size , Do not stretch or compress 
        self.pictureCameraBtn.clicked.connect(self.pictureCamera)
        
        self.videoCameraBtn = QPushButton(' videotape ')
        self.videoCameraBtn.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)
        self.videoCameraBtn.clicked.connect(self.videoCamera)
        
        self.openCameraBtn.setEnabled(True)
        self.closeCameraBtn.setEnabled(False)
        self.showcamera = QLabel(self)
        self.showcamera.resize(640, 480)
     
        self.hbox = QHBoxLayout(self)# Horizontal layout 
        self.hbox.addWidget(self.showcamera)# Add controls based on horizontal layout  addwidget() Method to add a control to a layout 
        
        self.vbox = QVBoxLayout(self)# Vertical layout 
        self.vbox.addWidget(self.openCameraBtn)
        self.vbox.addWidget(self.closeCameraBtn)
        self.vbox.addWidget(self.pictureCameraBtn)
        self.vbox.addWidget(self.videoCameraBtn)
        
        self.hbox.addLayout(self.vbox)
 
        self.setLayout(self.hbox)#setLayout Is to apply the set layout to the control 
        self.showcamera.setStyleSheet("background:black;")# Set the style ： The background is black 
        self.showcamera.setPixmap(QPixmap())# Set pixel 
        # self.move(300, 300)
        self.setWindowTitle('camera')
        self.setGeometry(600, 200, 760, 510)
        self.show()
 
    def closeEvent(self, event):
        reply = QMessageBox.question(self, ' Tips ', " Are you sure to quit? ?", QMessageBox.Yes |QMessageBox.No, QMessageBox.No)
        if reply == QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()
    
if __name__=='__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Here is the running video ：
【cameras- Bili, Bili 】 https://b23.tv/DY6bOAM

cameras