IndexError：列表索引超出范围 - 如果我的运动传感器无法检测到运动，为什么我的运动传感器会崩溃或检测到太多？

Question

我一直在使用Python和Pygame构建一个移动传感器，它基本上拍摄了您的相机镜头的图片，将每个像素的RGB值与最后拍摄的图片进行比较，并显示在Pygame屏幕中更改的像素。由于某种原因，如果它检测到过多的移动，例如您覆盖相机，或者它检测到太麻烦，例如您停止移动一段时间会崩溃。

代码：

import pygame
from pygame.locals import *
import pygame.camera
import pygame.image
import numpy as np
import cv2

pygame.init()
pygame.camera.init()
pygame.display.set_caption("Game")

cameras = pygame.camera.list_cameras()

print("Using camera %s ..." % cameras[0])

cam1 = pygame.camera.Camera(cameras[0])
cam1.start()

img1 = cam1.get_image()

flags = DOUBLEBUF
screen = pygame.display.set_mode((500,500), flags, 4)
frame = 0

def take_screen_shot():
    global frame
    save_file = str(frame)+'.png'#save file
    pygame.image.save(img1, save_file)

def image_proccesing():
    global frame
    global counter
    if frame >= 1:
        img1 = cv2.imread(str(frame - 1)+'.png', 0)
        img2 = cv2.imread(str(frame)+'.png', 0)
        sub = cv2.subtract(img1, img2)

        coords = np.argwhere(sub > 100)#checks if the pixels have a difference bigger than 100

        coords_list = coords.tolist()#converts the array into a list

        x = list(list(zip(*coords_list))[0])#grabs the first value, in this case x coordenates
        y = list(list(zip(*coords_list))[1])#grabs the first value, in this case y coordenates

        for i in range(len(x)):
            pygame.draw.rect(screen, (255, 0, 0), pygame.Rect(y[i], x[i], 1, 1))
        x.clear()
        y.clear()

clock = pygame.time.Clock()
while 1:
    screen.fill((0, 0, 0))
    for event in pygame.event.get():
        pygame.event.set_allowed(KEYDOWN)
        if event.type == QUIT or (event.type == KEYDOWN and event.key == K_ESCAPE):
            pygame.quit()
            pygame.camera.quit()

    img1 = cam1.get_image().convert()
    take_screen_shot()
    image_proccesing()
    clock.tick(15)
    pygame.display.update()
    frame += 1

错误：

    x = list(list(zip(*coords_list))[0])
IndexError: list index out of range

Answer 1

我发现了错误，我必须检查文件是否具有任何值。我通过更改image_proccesing函数来做到这一点。

image_proccesing：

global frame
    global counter
    if frame >= 1:
        img1 = cv2.imread('screenshots\\'+str(frame - 1)+'.png', 0)
        img2 = cv2.imread('screenshots\\'+str(frame)+'.png', 0)
        sub = cv2.subtract(img1, img2)

        coords = np.argwhere(sub > 100)
        coords_list = coords.tolist()
        if coords_list:
            x = list(list(zip(*coords_list))[0])
            y = list(list(zip(*coords_list))[1])

            for i in range(len(x)):
                pygame.draw.rect(screen, (255, 0, 0), pygame.Rect(y[i], x[i], 1, 1))
                if (x[i] > values[0][0] and x[i] < values[1][0]):
                    if (y[i] > values[1][1] and y[i] < values[0][1]):
                        print('ayo')
            x.clear()
            y.clear()