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Confused even after studying contours. Need more than 2 values to unpack

asked 2017-04-06 12:29:20 -0500

chrisbr gravatar image

line 30, in <module> (_,contours,hierarchy)=cv2.findContours(red,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) ValueError: need more than 2 values to unpack, I've studied the functions can't seem to find where my problem is can someone help with my code so I can try to learn by example and see where the problem is?

import cv2
import numpy as np cap=cv2.VideoCapture(0)

while(1): _, img = cap.read(0)

#converting frame(img i.e BGR) to HSV (hue-saturation-value)

hsv=cv2.cvtColor(img,cv2.COLOR_BGR2HSV)

#definig the range of red color
red_lower=np.array([136,87,111],np.uint8)
red_upper=np.array([180,255,255],np.uint8)

#finding the range of red,blue and yellow color in the image
red=cv2.inRange(hsv, red_lower, red_upper)

#Morphological transformation, Dilation     
kernal = np.ones((5 ,5), "uint8")

    red=cv2.dilate(red, kernal)
res=cv2.bitwise_and(img, img, mask = red)

#Tracking the Red Color
(_,contours,hierarchy)=cv2.findContours(red,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
for pic, contour in enumerate(contours):
    area = cv2.contourArea(contour)
    if(area>300):
        x,y,w,h = cv2.boundingRect(contour) 
        img = cv2.rectangle(img,(x,y),(x+w,y+h),(0,0,255),2)
        cv2.putText(img,"RED color",(x,y),cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0,0,255))


    #cv2.imshow("Redcolour",red)
    cv2.imshow("Color Tracking",img)
    #cv2.imshow("red",res)  
    if cv2.waitKey(10) & 0xFF == ord('q'):
        cap.release()
        cv2.destroyAllWindows()
        break
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answered 2017-04-06 16:49:23 -0500

berak gravatar image

the opencv2.4 version of findContours() only returns 2 args, not 3, like in thr opencv3 version.

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

should do the trick for you.

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Asked: 2017-04-06 12:29:20 -0500

Seen: 2,139 times

Last updated: Apr 06 '17