手势检测

Question

运行此命令时：

contours,_,hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

我收到此错误：

ValueError: not enough values to unpack (expected 3, got 2)

我也尝试过：

_, contours,hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

和：

contours,hierarchy,_ = cv2.findContours(thresh.copy(),cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

并收到此错误：

Traceback (most recent call last):
  File "C:/Users/HASHMATI/AppData/Local/Programs/Python/Python37-32/new2hand.py", line 152, in <module>
    gestureRecognition(frame,roi_rect,frame[y:y+h, x:x+w])
  File "C:/Users/HASHMATI/AppData/Local/Programs/Python/Python37-32/new2hand.py", line 99, in gestureRecognition
    detectGesture(src,roi_rect,img_dilated)
  File "C:/Users/HASHMATI/AppData/Local/Programs/Python/Python37-32/new2hand.py", line 21, in detectGesture
    contours,_,hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)
ValueError: not enough values to unpack (expected 3, got 2)

Answer 1

cv2.findContours()返回两个值，不能解压到轮廓，层次结构和_

应该是这样的：

contours, hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

或更多：

a, b, *others = [1, 2, 3, 4]

Answer 2

这是OpenCV 3.x和4.x之间的区别。在3.x中有三个返回值，在4.x中只有两个。正如其他人提到的那样，您仅捕获contours和hierarchy：

contours, hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

或者，如果实际需要使用3.x，则可以降级OpenCV版本。