temp.py

import argparse
import cv2
import numpy as np
import matplotlib.pyplot as plt
# import sys
 
# initialize the list of reference points and boolean indicating
# whether cropping is being performed or not
refPt = []
cropping = False
r=1.0
ref_ht=1790 
def click_and_crop(event, x, y, flags, param):
	# grab references to the global variables
	global refPt, cropping
 
	# if the left mouse button was clicked, record the starting
	# (x, y) coordinates and indicate that cropping is being
	# performed
	if event == cv2.EVENT_LBUTTONDOWN:
		pass
	elif event == cv2.EVENT_LBUTTONUP:
		refPt.append((x, y))
		cropping = False
 
ap = argparse.ArgumentParser()
ap.add_argument("-i", "--image", required=True, help="Path to the image")
args = vars(ap.parse_args())
 
# load the image, clone it, and setup the mouse callback function
image = cv2.imread(args["image"])
clone = image.copy()
cv2.namedWindow("image",cv2.WINDOW_NORMAL)
cv2.resizeWindow('image', 1000,800)
cv2.setMouseCallback("image", click_and_crop)
 
# keep looping until the 'q' key is pressed
while True:
	cv2.imshow("image", image)
	if(len(refPt)==4):
		break

	key = cv2.waitKey(1) & 0xFF

if len(refPt) == 4:
	print refPt

	dist=(refPt[0][0]-refPt[1][0])#**2 + (refPt[0][1]-refPt[1][1])**2;
	# dist=sqrt(dist)
	print dist

	pt1=np.asarray(refPt,dtype=np.float32)

	refPt[1]=(refPt[0][0]+dist,refPt[0][1])
	refPt[2]=(refPt[0][0],refPt[0][1]+dist)
	refPt[3]=(refPt[0][0]+dist,refPt[0][1]+dist)

	pt2=np.asarray(refPt,dtype=np.float32)

	M=cv2.getPerspectiveTransform(pt1,pt2)
	dst=cv2.warpPerspective(image,M,(image.shape[0],image.shape[1]))

	plt.subplot(121),plt.imshow(image),plt.title('Input')
	plt.subplot(122),plt.imshow(dst),plt.title('Output')
	plt.show()
	cv2.waitKey(0)

	# print pt1.shape
	# pt2=np.array([])


	# print type(refPt[0][0])

	# y_dist=abs(refPt[0][1]-refPt[1][1])
	# x_to_estimate=abs(refPt[2][0]-refPt[3][0])
	# actual_dist=ref_ht*r
	# print (y_dist)
	# print (x_to_estimate)
	# print (actual_dist/y_dist)*x_to_estimate

else:
	print "Didnt receive 4 points"
 
# close all open windows
cv2.destroyAllWindows()