How To Capture Frame With Opencv

Question

This is the main code that loads a pyqt gui form and it has 2 button one is for

starting webcam and second one is for capturing photos from frame .

I write the first button but i can't write the capture button.

import sys
import cv2
import numpy as np
from PyQt5.QtCore import QTimer
from PyQt5.QtGui import  QImage,QPixmap
from PyQt5.QtWidgets import QApplication , QDialog
from PyQt5.uic import loadUi

img_counter = 0

class video (QDialog):
    def __init__(self):
        super(video, self).__init__()
        loadUi('video.ui',self)
        self.image=None
        self.startButton.clicked.connect(self.start_webcam)
        self.capture.clicked.connect(self.keyPressEvent)

    def start_webcam(self):
        self.capture =cv2.VideoCapture(0)
        self.capture.set(cv2.CAP_PROP_FRAME_HEIGHT,480)
        self.capture.set(cv2.CAP_PROP_FRAME_WIDTH,640)

        self.timer=QTimer(self)
        self.timer.timeout.connect(self.update_frame)
        self.timer.start(5)

    def update_frame(self):
        ret,self.image=self.capture.read()
        self.image=cv2.flip(self.image,1)
        self.displayImage(self.image,1)

    def keyPressEvent(self):
        flag, frame= self.capture.read()
        path = 'J:\Face'
        cv2.imwrite(os.path.join(path,'wakka.jpg'), frame)

    def displayImage(self,img,window=1):
        qformat=QImage.Format_Indexed8
        if len(img.shape)==3 :
            if img.shape[2]==4:
                qformat=QImage.Format_RGBA8888
            else:
                qformat=QImage.Format_RGB888

        outImage=QImage(img,img.shape[1],img.shape[0],img.strides[0],qformat)

        outImage=outImage.rgbSwapped()


        if window==1:
            self.imgLabel.setPixmap(QPixmap.fromImage(outImage))
            self.imgLabel.setScaledContents(True)

if __name__=='__main__':
    app=QApplication(sys.argv)
    window=video()
    window.setWindowTitle('main code')
    window.show()
    sys.exit(app.exec_())

I want to capture photos from frames and save it in a folder.

The self.capture.clicked.connect(self.keyPressEvent) is for when we clicking on button.

I should write the function in keyPressEvent def

the capture.is for clicking a button

can someone help me through this?

Edit Note :

    if flag:

         QtWidgets.QApplication.beep(i)
         img_name = "opencv_frame_{}.png".format()
         cv2.imwrite(os.path.join(path,img_name), frame)

I want the condition for loop so that i can save the img_name format with counter but the counter must be number of clicking times

Answer 1

keyPressEvent is a method that allows you to capture the keys while the widget has the focus, and in your case it is not necessary, the solution is simple change its name, on the other hand I have improved your code.

import os
import cv2
import numpy as np
from PyQt5 import QtCore, QtGui, QtWidgets, uic

class video (QtWidgets.QDialog):
    def __init__(self):
        super(video, self).__init__()
        uic.loadUi('video.ui',self)
        self.startButton.clicked.connect(self.start_webcam)
        self.capture.clicked.connect(self.capture_image)
        self.imgLabel.setScaledContents(True)
        self.capture = None
        self.timer = QtCore.QTimer(self, interval=5)
        self.timer.timeout.connect(self.update_frame)
        self._image_counter = 0

    @QtCore.pyqtSlot()
    def start_webcam(self):
        if self.capture is None:
            self.capture =cv2.VideoCapture(0)
            self.capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
            self.capture.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
        self.timer.start()

    @QtCore.pyqtSlot()
    def update_frame(self):
        ret, image=self.capture.read()
        simage = cv2.flip(image, 1)
        self.displayImage(image, True)

    @QtCore.pyqtSlot()
    def capture_image(self):
        flag, frame= self.capture.read()
        path = r'J:\Face'
        if flag:
            QtWidgets.QApplication.beep()
            name = "opencv_frame_{}.png".format(self._image_counter) 
            cv2.imwrite(os.path.join(path, name), frame)
            self._image_counter += 1

    def displayImage(self, img, window=True):
        qformat = QtGui.QImage.Format_Indexed8
        if len(img.shape)==3 :
            if img.shape[2]==4:
                qformat = QtGui.QImage.Format_RGBA8888
            else:
                qformat = QtGui.QImage.Format_RGB888
        outImage = QtGui.QImage(img, img.shape[1], img.shape[0], img.strides[0], qformat)
        outImage = outImage.rgbSwapped()
        if window:
            self.imgLabel.setPixmap(QtGui.QPixmap.fromImage(outImage))

if __name__=='__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    window = video()
    window.setWindowTitle('main code')
    window.show()
    sys.exit(app.exec_())