Rect Module Python

Question

I have recently downloaded some code in python that tries to scan a receipt(or prepare for scanning). I tried to run the code, but there seems to be a problem. Python doesn't recognize the module 'Rect'. I tried to download the module, but there is no such module available. I'm stuck and am wondering what to do.

Note: Only one line of code uses the module

Code :

import cv2
import numpy as np
import rect

# add image here.
image = cv2.imread('test_pic.jpg')

# resize image
# choose optimal dimensions
image = cv2.resize(image, (1500, 880))

# create copy of original image
orig = image.copy()

# convert to grayscale and blur to smooth
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

# gaussian blur to smoothen texture
blurred = cv2.GaussianBlur(gray, (5, 5), 0)
#blurred = cv2.medianBlur(gray, 5)

# apply Canny Edge Detection
edged = cv2.Canny(blurred, 0, 50)
orig_edged = edged.copy()

# find the contours in the edged image
# keep only the largest ones, and
# initialize screen contour
(contours, _) = cv2.findContours(edged, cv2.RETR_LIST, cv2.CHAIN_APPROX_NONE)
contours = sorted(contours, key=cv2.contourArea, reverse=True)

#x,y,w,h = cv2.boundingRect(contours[0])
#cv2.rectangle(image,(x,y),(x+w,y+h),(0,0,255),0)

# get approximate contour
for c in contours:
    p = cv2.arcLength(c, True)
    approx = cv2.approxPolyDP(c, 0.02 * p, True)

    if len(approx) == 4:
        target = approx
        break


# map target points to 800x800 quadrilateral
approx = rect.rectify(target)
pts2 = np.float32([[0,0],[800,0],[800,800],[0,800]])

M = cv2.getPerspectiveTransform(approx,pts2)
dst = cv2.warpPerspective(orig,M,(800,800))

cv2.drawContours(image, [target], -1, (0, 255, 0), 2)
dst = cv2.cvtColor(dst, cv2.COLOR_BGR2GRAY)


# use thresholding on warped image to get scanned effect (If Required)
ret,th1 = cv2.threshold(dst,127,255,cv2.THRESH_BINARY)
th2 = cv2.adaptiveThreshold(dst,255,cv2.ADAPTIVE_THRESH_MEAN_C,\
            cv2.THRESH_BINARY,11,2)
th3 = cv2.adaptiveThreshold(dst,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C,\
            cv2.THRESH_BINARY,11,2)
ret2,th4 = cv2.threshold(dst,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)

# show results
cv2.imshow("Original.jpg", orig)
cv2.imshow("Original Gray.jpg", gray)
cv2.imshow("Original Blurred.jpg", blurred)
cv2.imshow("Original Edged.jpg", orig_edged)
cv2.imshow("Outline.jpg", image)
cv2.imshow("Thresh Binary.jpg", th1)
cv2.imshow("Thresh mean.jpg", th2)
cv2.imshow("Thresh gauss.jpg", th3)
cv2.imshow("Otsu's.jpg", th4)
cv2.imshow("dst.jpg", dst)

# other thresholding methods
"""
ret,thresh1 = cv2.threshold(dst,127,255,cv2.THRESH_BINARY)
ret,thresh2 = cv2.threshold(dst,127,255,cv2.THRESH_BINARY_INV)
ret,thresh3 = cv2.threshold(dst,127,255,cv2.THRESH_TRUNC)
ret,thresh4 = cv2.threshold(dst,127,255,cv2.THRESH_TOZERO)
ret,thresh5 = cv2.threshold(dst,127,255,cv2.THRESH_TOZERO_INV)

cv2.imshow("Thresh Binary", thresh1)
cv2.imshow("Thresh Binary_INV", thresh2)
cv2.imshow("Thresh Trunch", thresh3)
cv2.imshow("Thresh TOZERO", thresh4)
cv2.imshow("Thresh TOZERO_INV", thresh5)
"""

cv2.waitKey(0)
cv2.destroyAllWindows()

Answer 1

In the github repo you presumably grabbed the code from, there's another file called rect.py with a single function rectify() that is used in the main program. In Python, if you create other .py modules, you can import them into your code for better encapsulation of certain functions, although it seems really unnecessary in this code to keep the rectify() function in a different file altogether. Something that's equally basic but more common is a .py file with all your functions, and then a main .py file which uses those functions.

Edit: so to be clear, the rect module is in the repo itself. A word of advice, generally clone a whole repo unless you know for sure that you don't need the other files in it.