PlateExtraction.py

# -*- coding: utf-8 -*-
import cv2
import matplotlib.pyplot as plt

def plot_images(img1, img2, title1="", title2=""):
    fig = plt.figure(figsize=[15,15])
#     ax1 = fig.add_subplot(121)
#     ax1.imshow(img1, cmap="gray")
#     ax1.set(xticks=[], yticks=[], title=title1)

    ax2 = fig.add_subplot(122)
    ax2.imshow(img2, cmap="gray")
    ax2.set(xticks=[], yticks=[], title=title2)

def extraction(image):
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
#     plot_images(image, gray)
    blur = cv2.bilateralFilter(gray, 11,90, 90)
#     plot_images(gray, blur)
    edges = cv2.Canny(blur, 30, 200)
#     plot_images(blur, edges)
    cnts, new = cv2.findContours(edges.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)
    image_copy = image.copy()
    _ = cv2.drawContours(image_copy, cnts, -1, (255,0,255),2)
#     plot_images(image, image_copy)
    cnts = sorted(cnts, key=cv2.contourArea, reverse=True)[:30]
    image_copy = image.copy()
    _ = cv2.drawContours(image_copy, cnts, -1, (255,0,255),2)
#     plot_images(image, image_copy)
    plate = None
    for c in cnts:
        perimeter = cv2.arcLength(c, True)
        edges_count = cv2.approxPolyDP(c, 0.02 * perimeter, True)
        if len(edges_count) == 4:
            x,y,w,h = cv2.boundingRect(c)
            plate = image[y:y+h, x:x+w]
            break
    #plot_images(plate, plate)
    return plate