OpenCV Contours - need more than 2 values to unpack

问题:

I am trying to implement contours using the following code..

im = cv2.imread('C:\Users\Prashant\Desktop\T.jpg') imgray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY) ret,thresh = cv2.threshold(imgray,127,255,0) image, contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) img = cv2.drawContour(im, contours, -1, (0,255,0), 3) cv2.imshow('Image1',img) 

but i am continously getting the following error.

Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "C:\Python27\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 540, in runfile     execfile(filename, namespace)   File "C:/Users/Prashant/.spyder2/.temp.py", line 17, in <module>     image, contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) ValueError: need more than 2 values to unpack 

do the function findContours need more arguements?? wht could i do to correct it.

beginner

回答1:

In OpenCV 2, findContours returns just two values, contours and hierarchy. The error occurs when python tries to assign those two values to the three names given on left in this statement:

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

回答2:

It now returns three values:

findContours(image, mode, method[, contours[, hierarchy[, offset]]]) 

return image, contours, hierarchy

回答3:

findContours returns just three values image, contours and hierarchy in opencv3

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

回答4:

-findContours returns only two values. so use just,

So use

contours, hierarchy=cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)

文章来源: OpenCV Contours - need more than 2 values to unpack