在tkinter画布中闪烁的视频

Question

我正在尝试使用opencv和tkinter在我的GUI程序中捕获图像。捕获的图像保存在目录中并处理它并保存为pdf文件。但是当打开视频捕获窗口时，它总是闪烁。点击关闭按钮＆＃34; VIDIOC_DQBUF：无效的参数＆＃34;出现错误。

import datetime
import threading
from tkinter import *
from tkinter import Frame
from tkinter import ttk
import PIL.Image
import PIL.ImageTk
import cv2

from current_user_doc_manger import CurrentUserDocServer as cp


class ImageCaptureView(Frame):

    def __init__(self, master=None):
        Frame.__init__(self, master)

        self.master.title('Assid- Image Capture')
        self.pack()
        self.thread_flag = False
        self.scanned_document = cp.get_current_doc_text()
        self.username = cp.get_current_user_name()
        self.userdesig = cp.get_current_user_desig()
        self.userpen = cp.get_cur_user_pen()


        self.file_name = cp.get_current_user_doc_text()

        self.doc_label = ttk.Label(self, width=15, text='Document No: ' +
                    self.scanned_document)
        self.doc_label.pack(side='top', padx=10, pady=10, fill='both')

        self.canvas = Canvas(self)
        self.canvas.pack()
        self.btn_frame = Frame(self)
        self.btn_frame.pack(side='bottom', fill='both', expand='yes')
        self.create_btn_frame(self.btn_frame)




 def create_btn_frame(self, btn_frame):

        self.btn_cap = Button(btn_frame, text='capture',
                       command=self.create_a_snap)
        self.btn_cap.pack(side='left', fill='both', expand='yes', padx=10, pady=10)

        self.btn_next = Button(btn_frame, text='next', command=self.create_a_snap)
        self.btn_next.pack(side='left', fill='both', expand='yes', padx=10, pady=10)

        btn_close = Button(btn_frame, text='close', command=self.close_camera)
        btn_close.pack(side='left', fill='both', expand='yes', padx=10, pady=10)




    def create_image_process_thread(self):
        self.thread_flag = True
        self.image_thread = threading.Thread(target=self.videoloop, args=())
        self.image_thread.daemon = True
        self.image_thread.start()


    def create_a_snap(self):
        cv2.imwrite(self.file_name + '-' +
                    datetime.datetime.now().strftime('%d.%m.%Y %H:%M:%S.2%f') + '.jpg',
                    self.frame)

    def close_camera(self):
            self.cam.release()
            self.thread_flag = False
            self.destroy()
            cp.set_bookno('None')
            cp.set_doc_year('None')
            cp.set_doc_no('None')


    def videoloop(self):
        self.thread_flag = True
        try:
            self.cam = cv2.VideoCapture(0)
        except:
            pass

        while self.thread_flag:
            ret, self.frame = self.cam.read()
            if not ret:
                self.cam.release()
                break
            else:
                try:
                    self.width = self.cam.get(cv2.CAP_PROP_FRAME_WIDTH)
                    self.height = self.cam.get(cv2.CAP_PROP_FRAME_HEIGHT)
                    self.gray = cv2.cvtColor(self.frame, cv2.COLOR_BGR2GRAY)
                    self.photo = PIL.ImageTk.PhotoImage(image=PIL.Image.fromarray(self.gray))
                    self.canvas.config(width=int(self.width), height=int(self.height))
                    self.canvas.create_image(0, 0, image=self.photo, anchor=NW)


                except ValueError:
                    self.cam.release()
                    break






if __name__ == '__main__':
        x = ImageCaptureView()
        x.create_image_process_thread()

        x.mainloop()