cam_scanner.py

from pyimagesearch.transform import four_point_transform
from pyimagesearch import imutils
from skimage.filters import threshold_adaptive
import numpy as np
import argparse
import cv2
from matplotlib import pyplot as plt
x=cv2.imread('IMG_20170227_174134.jpg')



ratio = x.shape[0] / 500.0
orig = x.copy()
x = imutils.resize(x, height = 500)

gray = cv2.cvtColor(x, cv2.COLOR_BGR2GRAY)
gray = cv2.GaussianBlur(gray, (5, 5), 0)
edged = cv2.Canny(gray, 75, 200)

cv2.imshow("a", edged)
cv2.waitKey(0)
cv2.destroyAllWindows()

#imgray = cv2.cvtColor(x,cv2.COLOR_BGR2GRAY)
#ret,thresh = cv2.threshold(imgray,127,255,0)
im2, contours, hierarchy = cv2.findContours(edged.copy(),cv2.RETR_TREE,cv2.CHAIN_APPROX_NONE)
#c = max(contours, key = cv2.contourArea)
#(cnts, _, _) = cv2.findContours(edged.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)
#cnts = sorted(cnts, key = cv2.contourArea, reverse = True)[:5]

# loop over the contours
for c in contours:
	# approximate the contour
	peri = cv2.arcLength(c, True)
	approx = cv2.approxPolyDP(c, 0.02 * peri, True)

	# if our approximated contour has four points, then we
	# can assume that we have found our screen
	if len(approx) == 4:
		screenCnt = approx
		break

# show the contour (outline) of the piece of paper
print "STEP 2: Find contours of paper"
cv2.drawContours(x, [screenCnt], -1, (0, 255, 0), 2)
cv2.imshow("Outline", x)
cv2.waitKey(0)
cv2.destroyAllWindows()

# apply the four point transform to obtain a top-down
# view of the original image
warped = four_point_transform(orig, screenCnt.reshape(4, 2) * ratio)

# convert the warped image to grayscale, then threshold it
# to give it that 'black and white' paper effect
#warped = cv2.cvtColor(warped, cv2.COLOR_BGR2GRAY)
#warped = threshold_adaptive(warped, 251, offset = 10)
#warped = warped.astype("uint8") * 255

# show the original and scanned images
print "STEP 3: Apply perspective transform"
cv2.imshow("Original", imutils.resize(orig, height = 650))
cv2.imshow("Scanned", imutils.resize(warped, height = 650))
cv2.waitKey(0)