OpenCV轮廓 - 需要2个以上的值才能打开包装

Question

我正在尝试使用以下代码实现轮廓..

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)

但我不断收到以下错误.

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

做函数findContours需要更多的论证？我可以做些什么来纠正它.

初学者

Answer 1

在OpenCV 2中,findContours只返回两个值,contours和hierarchy.当python尝试将这两个值分配给此语句左侧给出的三个名称时,会发生错误:

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

Answer 2

它现在返回三个值：

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

返回图像、轮廓、层次结构