(-215:Assertion failed) npoints >= 0 && (depth == CV_32F || depth == CV_32S) in function 'contourArea'

Question

I am trying to run the website code to create the image.

When I run the code it gives me an error:

cv2.error: OpenCV(4.1.0) 
/Users/travis/build/skvark/opencv-python/opencv/modules/imgproc/src/shapedescr.cpp:274: 
error: (-215:Assertion failed) npoints >= 0 && (depth == CV_32F || depth == CV_32S) 
in function 'contourArea'

I am not sure about the reason behind it.

Is your image in 32 bit format? – Thomas Weller Jun 30 '19 at 23:13 — Thomas Weller, Jun 30 '19 at 23:13

score 10 · Accepted Answer · answered Jun 30 '19 at 23:17

10

The repo is clearly written for OpenCV 3.x. But, you are running on OpenCV 4.1. Repo code takes find_contour's second return value for contours( find_contours(...)[1] ). You should change 1 to 0.

answered Jun 30 '19 at 23:17

Sıddık Açıl

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score 3 · Answer 2 · edited Aug 23 '22 at 06:39

3

cnts = cv2.findContours(...)[0]

this should solve your problem as in OpenCV (4>) findContours(...)[0] gives you the contours

edited Aug 23 '22 at 06:39

Jeru Luke

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answered Mar 05 '20 at 11:32

Sahana M

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(-215:Assertion failed) npoints >= 0 && (depth == CV_32F || depth == CV_32S) in function 'contourArea'

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