preprocess.py

import numpy
import cv2


def contour_coordinates(contour):
	'''
	Returns coordinates of a contour
	'''
	if cv2.contourArea(contour) > 10:
		M = cv2.moments(contour)
		return (int(M['m10']/M['m00']))

def drawSquare(image):
	'''
	Draws a square around the found digits
	'''		
	b = [0,0,0]
	height, width = image.shape[0], image.shape[1]
	if(height == width): ## if square
		square = image
		return square
	else:
		d_size = cv2.resize(image, (2*width, 2*height), interpolation=cv2.INTER_CUBIC)
		height, width = height * 2, width * 2
		if (height > width):
			padding = (height - width)/2
			d_size_square = cv2.copyMakeBorder(d_size, 0, padding, padding, cv2.BORDER_CONSTANT, value=b)
		else:
			padding = (width - height)/2
			d_size_square = cv2.copyMakeBorder(d_size, padding, padding, 0, 0, cv2.BORDER_CONSTANT, value=b)

	return d_size_square

def resize(image, dim):
	'''
	Returns orignal image resized to shape 'dim'
	'''	
	b = [0,0,0]	 			
	dim = dim - 4
	squared = image
	r = (float(dim) / squared.shape[1])
	d = (dim, int(squared.shape[0] * r))
	resized = cv2.resize(image, d, interpolation = cv2.INTER_AREA)
	height, width = resized.shape[0], resized[1]
	if (height > width):
		resized = cv2.copyMakeBorder(resized, 0,0,0,1, cv2.BORDER_CONSTANT, value=b)
	if (height < width):
		resized = cv2.copyMakeBorder(resized, 1,0,0,0, cv2.BORDER_CONSTANT, value=b)

	resized = cv2.copyMakeBorder(resized, 2,2,2,2,cv2.BORDER_CONSTANT, value=b)
	height, width = resized.shape[0], resized.shape[1]	
	
	return resized