与openCV 3中contourArea的兼容性问题 [英] compatibility issue with contourArea in openCV 3

问题描述

我正在尝试对从findContours获得的轮廓进行简单的面积计算. 我的openCv版本是3.1.0

I am trying to do a simple area calculation of contours I get from findContours. My openCv version is 3.1.0

我的代码是:

cc = cv2.findContours(im_bw.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
cv2.contourArea(cc[0])

error: 'C:\\builds\\master_PackSlaveAddon-win32-vc12-static\\opencv\\modules\\imgproc\\src\\shapedescr.cp...: error: (-215) npoints >= 0 && (depth == CV_32F || depth == CV_32S) in function cv::contourArea\n'

似乎无法解决这个问题，我感觉它只是进行了类型转换，我希望findContours结果能够与contourArea的类型相匹配

Cant seem to solve it, I have a feeling its just typecasting altough I expect the findContours result to match the type of contourArea

谢谢:)

原来我需要使用findContours的第二个参数

turns out I need to take the 2nd argument of findContours

 im2, cc, hierarchy = cv2.findContours(im_bw.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

推荐答案

在Opencv 3 API版本中，cv2.findContours()返回3

In Opencv 3 API version the cv2.findContours() returns 3 objects

• 图片
• 轮廓
• 层次结构

因此，您需要将语句重写为:

So you need to rewrite your statement as:

image, contours, hierarchy = cv2.findContours(im_bw.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

这篇关于与openCV 3中contourArea的兼容性问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！