如何从图像中删除有图案的背景?

我有一张图片,是一帧视频。如您所见 original image 背景具有一种模式,使得检测乐高物体变得具有挑战性。根据我目前的代码,对象边缘被错误地检测到,并与背景的形状混淆,结果是 this image 。结果显示为矩形 here .我的代码:

import cv2
import numpy as np

main_image = cv2.imread('image.jpg', 1)
convert_to_gray = cv2.cvtColor(main_image, cv2.COLOR_BGR2GRAY)
convert_to_blurred = cv2.GaussianBlur(convert_to_gray, (3, 3), 2)
a, b = cv2.threshold(convert_to_blurred, 0, 255, cv2.THRESH_BINARY | cv2.THRESH_OTSU)
canny_result = cv2.Canny(convert_to_blurred, a / 6, b / 3)
k = np.ones((2, 2), np.uint8)
d = cv2.dilate(canny_result, k, iterations=3)

contours_found = cv2.findContours(d, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
contours_found = contours_found[0] if len(contours_found) == 2 else contours_found[1]

for cont in contours_found:
    x, y, w, h = cv2.boundingRect(cont)
    cv2.rectangle(main_image, (x, y), (x + w, y + h), (0, 0, 255), 3)

cv2.imshow('canny_result', canny_result)
cv2.imshow('main_image', main_image)
cv2.waitKey(0)

如何正确检测物体?