使用cv2.findContours（）与python时出错 [英] Error using cv2.findContours(), with python

问题描述

我最近开始在Python上学习OpenCV。

I've recently started learning OpenCV on Python.

我指的是这个教程，以获得一些关于获取图像轮廓的帮助。

I'm referring to this tutorial here, to get some help on getting the contours of an image.

我的代码是 -

import cv2
import numpy as np

img = cv2.imread('shapes.jpg', 0)
img = cv2.medianBlur(img, 5)
thresh =     cv2.adaptiveThreshold(img,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C,\
cv2.THRESH_BINARY,11,2)

cv2.imshow('Thresh', thresh)
cv2.waitKey(0)
cv2.destroyAllWindows()

image, contours, hierarchy =   cv2.findContours(thresh.copy(),cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

cv2.drawContours(image, countours, -1, (0,255,0), 3)
cv2.imshow('Contours', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

出现第一个阈值图像，bu之后我收到一条错误消息

The first thresholded image is appearing, but after that I get an error message as

Traceback (most recent call last):
  File "contours.py", line 21, in <module>
    image, contours, hierarchy =     cv2.findContours(thresh.copy(),cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)
ValueError: need more than 2 values to unpack

我们将不胜感激任何解决此问题的帮助。

Any help to resolve this issue will be appreciated.

推荐答案

请参阅此示例。

cv2.findContours(...)

只返回两个对象，你试图将它解压缩为三个。

only returns two objects, you're trying to unpack it into three.

将该行更改为：

contours, hierarchy =   cv2.findContours(thresh.copy(),cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

它应该有效。

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