TypeError：“NoneType”对象不可下标问题

Question

我尝试在 opencv python 上运行我的自行车检测。当我运行它时它可以正常工作，但是当程序结束时它会出错。我不知道如何解决它。谁能告诉我问题出在哪里？

import cv2
import numpy as np
import pygame
import datetime as dt
from pygame import mixer
import time

#=============== Variable Mouse ==================#
drawing = False
point1 = ()
point2 = ()

drawingTwo = False
pointTwo_1 = ()
pointTwo_2 = ()
Mouse_count = False
#================================================#
def mouse_drawing(event, x, y, flags, params):
    global point1, point2, drawing
    global pointTwo_1, pointTwo_2, drawingTwo, Mouse_count

    #----------Mouse 1-------
    if Mouse_count == False:
        if event == cv2.EVENT_LBUTTONDOWN:
            if drawing is False:
                drawing = True
                point1 = (x, y)
            #else:
                #drawing = False

        elif event == cv2.EVENT_MOUSEMOVE:
            if drawing is True:
                point2 = (x, y)
        elif event == cv2.EVENT_LBUTTONUP:
            drawing = False
            Mouse_count = True



#================================================#
lastTime = dt.datetime.now()
currentTime = dt.datetime.now()

#Make Sound
pygame.mixer.init()


#create VideoCapture object and read from video file


cap = cv2.VideoCapture('test13.mp4')

cv2.namedWindow("Detecion motor")
cv2.setMouseCallback("Detecion motor", mouse_drawing)

while True:
    ret, frame = cap.read()
    car_cascade = cv2.CascadeClassifier('cascade11.xml')

    #============================== ROI One ============================#
    if point1 and point2:

        #Rectangle marker
        r = cv2.rectangle(frame, point1, point2, (100, 50, 200), 5)
        frame_ROI = frame[point1[1]:point2[1],point1[0]:point2[0]]

        #------------------Detect car ROI-------------------#
        if drawing is False:
            #convert video into gray scale of each frames
            ROI_grayscale = cv2.cvtColor(frame_ROI, cv2.COLOR_BGR2GRAY)
            #detect cars in the video
            cars_ROI = car_cascade.detectMultiScale(ROI_grayscale, 1.1, 3)
            if len(cars_ROI) > 0:
                if (currentTime - lastTime).seconds > 20:
                    lastTime = dt.datetime.now()
                    sound = mixer.Sound('sirine2.wav')
                    sound.play()

            for (x, y, w, h) in cars_ROI:
                cv2.rectangle(frame_ROI, (x, y), (x + w, y + h), (0, 255, 0), 2)
                currentTime = dt.datetime.now()
                # cv2.putText(frame_ROI, "Jumlah Motor : " + str(cars_ROI.shape[0]), (10,frame_ROI.shape[0] -25), cv2.FONT_HERSHEY_TRIPLEX, 0.5,(0,255,0), 1)
            # -------------------------------------------------#

    #============================== ROI Two ============================#

    #==================================================================#
    cv2.imshow("Detecion motor", frame)

    if cv2.waitKey(25) & 0xFF == ord('q'):
        break


cap.release()
cv2.destroyAllWindows()

然后错误是：

Traceback (most recent call last):
  File "D:/Skripsi/CarDetection-master/DeteksiMotor.py", line 65, in <module>
    frame_ROI = frame[point1[1]:point2[1],point1[0]:point2[0]]
TypeError: 'NoneType' object is not subscriptable

Answer 1

优化@mkrieger1 的评论，我们可以在您的代码中看到您正在检查point1 和point2 是否都转换为布尔真，所以问题不存在。默认情况下，这意味着frame 等于无。替换你的行：

if point1 and point2:

与：

if frame and point1 and point2:

我的意思是，frame 是看起来像输入操作的结果，而这些操作可能会以多种创造性的方式失败。