用 OpenCV 填充轮廓

Question

I have an image with a black background and some red outlines of polygons, like this:

I want now to fill those polygons with the same colour, so they look something like this:

I tried using OpenCV, but it doesn't seem to work:

import cv2

image = cv2.imread("image_to_read.jpg")

gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

_, contours, _ = cv2.findContours(gray_image, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)

for contour in contours:
    cv2.drawContours(image, [contour], 0, (255, 0, 0), -1)

cv2.imshow("Filled Image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()

I am getting this error:

ValueError: not enough values to unpack (expected 3, got 2)

Any help would be appreciated!

Answer 1

As DanMašek suggested in the comments, modifying the unpacking of the tuple is the answer.

import cv2

img = cv2.imread('output.jpg')

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

contours, hierarchy = cv2.findContours(edged, 
    cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
  
for contour in contours:
cv2.drawContours(image, [contour], 0, (255, 0, 0), -1)

cv2.imshow("Filled Image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()