GUI开发：实时显示摄像头图像

 import tkinter as tk
 from PIL import Image, ImageTk
 import cv2
 import numpy as np
 import time

 g_exit = False

 def close_window():
     global g_exit
     g_exit = True

 def video_init():
     cap = cv2.VideoCapture(0)
     cap.set(3, 640)
     cap.set(4, 480)
     time.sleep(2)
     return cap

 def video_show():
     cap = video_init()
     while (cap.isOpened() and g_exit == False):
         ret, frame = cap.read()
         if ret == True:
             frame = cv2.flip(frame, 1)
             # 将图像的通道顺序由BGR转换成RGB
             frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
             if isinstance(frame, np.ndarray):
                 frame = Image.fromarray(frame.astype(np.uint8))

             photo = ImageTk.PhotoImage(image=frame)
             image_cvs.create_image([320, 240], image=photo)

             win.update_idletasks()
             win.update()
     cap.release()
     win.quit()

 if __name__ == '__main__':
     win = tk.Tk()
     image_cvs = tk.Canvas(win, width=640, height=480, bg='white')
     image_cvs.pack()

     # 点击界面右上角的关闭按钮时，会触发'WM_DELETE_WINDOW'消息
     # 我们在此截获该消息，并改变其行为
     win.protocol('WM_DELETE_WINDOW', close_window)

     win.after(200, video_show)
     win.mainloop()

在使用Canvas显式图片时，其image参数有两个重要的点需要注意，一个是格式，另外一个是要保持持续引用（可使用全局变量）。如下：

• The image object should be a PhotoImage or BitmapImage, or a compatible object (such as the PIL PhotoImage).
• The application must keep a reference to the image object.