python中执行其他的python脚本（一）：

代码main.py：

from PyQt5 import QtCore, QtGui, QtWidgets
import faceSet 


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(519, 354)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(210, 140, 75, 23))
        self.pushButton.setObjectName("pushButton")
        MainWindow.setCentralWidget(self.centralwidget)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "Open"))

        self.pushButton.clicked.connect(self.OpenClick)

    def OpenClick(self):
        #algorithm.FunctionAlgo()
        faceSet.mySet()



if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

代码faceSet.py：

''''
Capture multiple Faces from multiple users to be stored on a DataBase (dataset directory)
    ==> Faces will be stored on a directory: dataset/ (if does not exist, pls create one)
    ==> Each face will have a unique numeric integer ID as 1, 2, 3, etc                       
Based on original code by Anirban Kar: https://github.com/thecodacus/Face-Recognition    
Developed by Marcelo Rovai - MJRoBot.org @ 21Feb18    
'''

import cv2
import os

def mySet():
    cam = cv2.VideoCapture(0)
    cam.set(3, 640) # set video width
    cam.set(4, 480) # set video height

    face_detector = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')

    # For each person, enter one numeric face id
    face_id = input('\n enter user id end press <return> ==>  ')

    print("\n [INFO] Initializing face capture. Look the camera and wait ...")
    # Initialize individual sampling face count
    count = 0

    while(True):

        ret, img = cam.read()
        img = cv2.flip(img, 1) # flip video image vertically
        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        faces = face_detector.detectMultiScale(gray, 1.3, 5)

        for (x,y,w,h) in faces:

            cv2.rectangle(img, (x,y), (x+w,y+h), (255,0,0), 2)     
            count += 1

            # Save the captured image into the datasets folder
            cv2.imwrite("dataset/User." + str(face_id) + '.' + str(count) + ".jpg", gray[y:y+h,x:x+w])

            cv2.imshow('image', img)

        k = cv2.waitKey(100) & 0xff # Press 'ESC' for exiting video
        if k == 27:
            break
        elif count >= 30: # Take 30 face sample and stop video
             break

    # Do a bit of cleanup
    print("\n [INFO] Exiting Program and cleanup stuff")
    cam.release()
    cv2.destroyAllWindows()

运行：

弹出一个有运行按键的界面，单击界面，执行我需要的程序;

结果为：

enter user id end press <return> ==>  QCoreApplication::exec: The event loop is already running
1

 [INFO] Initializing face capture. Look the camera and wait ...
OpenCV(3.4.1) Error: Assertion failed (scn == 3 || scn == 4) in cvtColor, file /home/pi/opencv-3.4.1/modules/imgproc/src/color.cpp, line 11147
Traceback (most recent call last):
  File "main.py", line 29, in OpenClick
    faceSet.mySet()
  File "/home/pi/pro1/faceSet.py", line 30, in mySet
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
cv2.error: OpenCV(3.4.1) /home/pi/opencv-3.4.1/modules/imgproc/src/color.cpp:11147: error: (-215) scn == 3 || scn == 4 in function cvtColor
已放弃

这就对了