Python openn Cv2绘制等高线

我正在运行此代码，但遇到了一个错误

cv2.drawContours(image,contours,-1,(0,255,0),3)

error: OpenCV(3.4.3) D:\Build\OpenCV\opencv-3.4.3\modules\imgproc\src\drawing.cpp:2511: error: (-215:Assertion failed) npoints > 0 in function 'cv::drawContours'

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收集FindOnTours（）的输出时，顺序应如下所示：

image, contours, hierarchy = cv2.findContours(...)

在您的具体情况下，您应该写下（我省略了imshow步骤）：

image, contours, hierarchy = cv2.findContours(...)

import cv2
import numpy as np

image = cv2.imread("./input1.jpg")

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

edged = cv2.Canny(gray, 30, 200)

_, contours, hierarchy = cv2.findContours(edged, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)

print(f"Number of Contours found = {len(contours)}")

cv2.drawContours(image, contours, -1, (0,255,0), 3)