contours and hirerachy mismatch

edit

Hi When I use the below code without bothering hirerachy , it is able to detect external contours correctly . Pl see the attached file “drawn-NO-hirerachy”. My original image has three external contours .

cnts = cv2.findContours(edged.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

when I use hirerachy code , it is not detecting external contours correctly . It shows a few points that I red circled in “drawa-with hirerachy”

im,cnts,hierarchy = cv2.findContours(edged.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

Following is the code I am using

# import the necessary packages
import numpy as np
import cv2
import imutils
import pytesseract
from PIL import Image, ImageEnhance
from imutils.perspective import four_point_transform
from array import *


# load the example image
image = cv2.imread("h2.jpg")

# pre-process the image by resizing it, converting it to
# graycale, blurring it, and computing an edge map
image = imutils.resize(image, height=500)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blurred = cv2.GaussianBlur(gray, (5, 5), 0)
edged = cv2.Canny(blurred, 50, 200, 255)

#cnts = cv2.findContours(edged.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

im,cnts,hierarchy = cv2.findContours(edged, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

cnts = cnts[0] if imutils.is_cv2() else cnts[1]

cnts = sorted(cnts, key=cv2.contourArea, reverse=True)


print 'No Of Contours =  ', len(cnts)

print 'No Of elements in hirerachy =  ', len(hierarchy[0])
print hierarchy

major = cv2.__version__.split('.')[0]

print major

for c in cnts:
    cv2.drawContours(image, [c], -1, (0,255,0), 2)

cv2.imshow('EDGED',edged)
cv2.imshow('DRAWN CONTOURS',image)
cv2.imshow('RETURNED IMAGE',im)
cv2.waitKey(0)