license_plate_extraction.py

import cv2
def extract_plate(img): # the function detects and perfors blurring on the number plate.
	plate_img = img.copy()
	
	#Loads the data required for detecting the license plates from cascade classifier.
	plate_cascade = cv2.CascadeClassifier('./indian_license_plate.xml')

	# detects numberplates and returns the coordinates and dimensions of detected license plate's contours.
	plate_rect = plate_cascade.detectMultiScale(plate_img, scaleFactor = 1.3, minNeighbors = 7)

	for (x,y,w,h) in plate_rect:
		a,b = (int(0.02*img.shape[0]), int(0.025*img.shape[1])) #parameter tuning
		plate = plate_img[y+a:y+h-a, x+b:x+w-b, :]
		# finally representing the detected contours by drawing rectangles around the edges.
		cv2.rectangle(plate_img, (x,y), (x+w, y+h), (51,51,255), 3)
        
	return plate_img, plate # returning the processed image.