car_id_detect.py

'''
基于形状和色调的检测车牌号并提取车牌号图片
'''
import cv2
import numpy as np
from numpy.linalg import norm
import sys
import os
import json
from PIL import Image

SZ = 20          # 训练图片长宽
MAX_WIDTH = 1000 # 原始图片最大宽度
Min_Area = 2000  # 车牌区域允许最大面积
PROVINCE_START = 1000


def point_limit(point):
    if point[0] < 0:
        point[0] = 0
    if point[1] < 0:
        point[1] = 0

def accurate_place(card_img_hsv, limit1, limit2, color,cfg):
    row_num, col_num = card_img_hsv.shape[:2]
    xl = col_num
    xr = 0
    yh = 0
    yl = row_num
    #col_num_limit = cfg["col_num_limit"]
    row_num_limit = cfg["row_num_limit"]
    col_num_limit = col_num * 0.8 if color != "green" else col_num * 0.5 # 绿色有渐变
    for i in range(row_num):
        count = 0
        for j in range(col_num):
            H = card_img_hsv.item(i, j, 0)
            S = card_img_hsv.item(i, j, 1)
            V = card_img_hsv.item(i, j, 2)
            if limit1 < H <= limit2 and 34 < S and 46 < V:
                count += 1
        if count > col_num_limit:
            if yl > i:
                yl = i
            if yh < i:
                yh = i
    for j in range(col_num):
        count = 0
        for i in range(row_num):
            H = card_img_hsv.item(i, j, 0)
            S = card_img_hsv.item(i, j, 1)
            V = card_img_hsv.item(i, j, 2)
            if limit1 < H <= limit2 and 34 < S and 46 < V:
                count += 1
        if count > row_num - row_num_limit:
            if xl > j:
                xl = j
            if xr < j:
                xr = j
    return xl, xr, yh, yl



def CaridDetect(car_pic):
    sign = 1
    # 加载图片
    img = cv2.imread(car_pic)
    valid2 = True
    try:
        pic_hight, pic_width = img.shape[:2]
    except AttributeError:
        print('图像读取错误')
        valid2 = False
    if valid2 == False:
        return 0,0,0,0
    pic_hight, pic_width = img.shape[:2]

    if pic_width > MAX_WIDTH:
        resize_rate = MAX_WIDTH / pic_width
        img = cv2.resize(img, (MAX_WIDTH, int(pic_hight*resize_rate)), interpolation=cv2.INTER_AREA)
    # 车牌识别的部分参数保存在js中，便于根据图片分辨率做调整
    f = open('config.js')
    j = json.load(f)
    for c in j["config"]:
        if c["open"]:
            cfg = c.copy()
            break
        else:
            raise RuntimeError('[ ERROR ] 没有设置有效配置参数.')
    
    blur = cfg["blur"]
    # 高斯去噪
    if blur > 0:
        img = cv2.GaussianBlur(img, (blur, blur), 0) #图片分辨率调整
    oldimg = img
    img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    #equ = cv2.equalizeHist(img)
    #img = np.hstack((img, equ))
    # 去掉图像中不会是车牌的区域
    kernel = np.ones((20, 20), np.uint8)
    # morphologyEx 形态学变化函数
    img_opening = cv2.morphologyEx(img, cv2.MORPH_OPEN, kernel)
    img_opening = cv2.addWeighted(img, 1, img_opening, -1, 0);

    # 找到图像边缘 Canny边缘检测
    ret, img_thresh = cv2.threshold(img_opening, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)
    img_edge = cv2.Canny(img_thresh, 100, 200)
    # 使用开运算和闭运算让图像边缘成为一个整体
    kernel = np.ones((cfg["morphologyr"], cfg["morphologyc"]), np.uint8)
    img_edge1 = cv2.morphologyEx(img_edge, cv2.MORPH_CLOSE, kernel)
    img_edge2 = cv2.morphologyEx(img_edge1, cv2.MORPH_OPEN, kernel)

    # 查找图像边缘整体形成的矩形区域，可能有很多，车牌就在其中一个矩形区域中
    # cv2.findContours()函数来查找检测物体的轮廓
    try:
        contours, hierarchy = cv2.findContours(img_edge2, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    except ValueError:
        image, contours, hierarchy = cv2.findContours(img_edge2, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    contours = [cnt for cnt in contours if cv2.contourArea(cnt) > Min_Area]
    # print('[ INFO ] len(contours): {}'.format(len(contours)))
    
    # 一一排除不是车牌的矩形区域，找到最小外接矩形的长宽比复合车牌条件的边缘检测到的物体
    car_contours = []
    for cnt in contours:
        rect = cv2.minAreaRect(cnt) 
        # 生成最小外接矩形，点集 cnt 存放的就是该四边形的4个顶点坐标（点集里面有4个点）
        # 函数 cv2.minAreaRect() 返回一个Box2D结构rect：（最小外接矩形的中心（x，y），（宽度，高度），旋转角度），
        # 但是要绘制这个矩形，我们需要矩形的4个顶点坐标box, 通过函数 cv2.boxPoints() 获得，
        # 返回形式[ [x0,y0], [x1,y1], [x2,y2], [x3,y3] ]。

        # 得到的最小外接矩形的4个顶点顺序、中心坐标、宽度、高度、旋转角度（是度数形式，不是弧度数）
        # https://blog.csdn.net/lanyuelvyun/article/details/76614872

        area_width, area_height = rect[1]
        if area_width < area_height:
            area_width, area_height = area_height, area_width
        wh_ratio = area_width / area_height
        #print(wh_ratio)
        # 要求矩形区域长宽比在2到5.5之间，2到5.5是车牌的长宽比，其余的矩形排除 一般的比例是3.5
        if wh_ratio > 2 and wh_ratio < 5.5:
            car_contours.append(rect)
            box = cv2.boxPoints(rect)
            box = np.int0(box)
            #oldimg = cv2.drawContours(oldimg, [box], 0, (0, 0, 255), 2)
            #cv2.imshow("edge4", oldimg)
            #print(rect)
    # print("[ INFo ] len(car_contours): {}".format(len(car_contours)))
    # print("[ INFO ] 精确定位.")

    card_imgs = []

    # 矩形区域可能是倾斜的矩形，需要矫正，以便使用颜色定位
    # 这个就是为什么我们不选择YOLO,SSD或其他的目标检测算法来检测车牌号的原因！！！（给自己偷懒找个台阶 :) )
    for rect in car_contours:
        if rect[2] > -1 and rect[2] < 1:#创造角度，使得左、高、右、低拿到正确的值
            angle = 1
        else:
            angle = rect[2]
        rect = (rect[0], (rect[1][0]+5, rect[1][1]+5), angle)#扩大rect范围，避免车牌边缘被排除 

        box = cv2.boxPoints(rect)
        # 避免边界超出图像边界
        heigth_point = right_point = [0, 0]
        left_point = low_point = [pic_width, pic_hight]
        for point in box:
            if left_point[0] > point[0]:
                left_point = point
            if low_point[1] > point[1]:
                low_point = point
            if heigth_point[1] < point[1]:
                heigth_point = point
            if right_point[0] < point[0]:
                right_point = point

        if left_point[1] <= right_point[1]: # 正角度
            new_right_point = [right_point[0], heigth_point[1]]
            pts2 = np.float32([left_point, heigth_point, new_right_point])#字符只是高度需要改变
            pts1 = np.float32([left_point, heigth_point, right_point])
            M = cv2.getAffineTransform(pts1, pts2) # 仿射变换
            dst = cv2.warpAffine(oldimg, M, (pic_width, pic_hight))
            point_limit(new_right_point)
            point_limit(heigth_point)
            point_limit(left_point)
            card_img = dst[int(left_point[1]):int(heigth_point[1]), int(left_point[0]):int(new_right_point[0])]
            card_imgs.append(card_img)
            #cv2.imshow("card", card_img)
            #cv2.waitKey(0)
        elif left_point[1] > right_point[1]: # 负角度
            
            new_left_point = [left_point[0], heigth_point[1]]
            pts2 = np.float32([new_left_point, heigth_point, right_point])#字符只是高度需要改变
            pts1 = np.float32([left_point, heigth_point, right_point])
            M = cv2.getAffineTransform(pts1, pts2)
            dst = cv2.warpAffine(oldimg, M, (pic_width, pic_hight))
            point_limit(right_point)
            point_limit(heigth_point)
            point_limit(new_left_point)
            card_img = dst[int(right_point[1]):int(heigth_point[1]), int(new_left_point[0]):int(right_point[0])]
            card_imgs.append(card_img)
            #cv2.imshow("card", card_img)
            #cv2.waitKey(0)

    # 开始使用颜色定位，排除不是车牌的矩形，目前只识别蓝、绿、黄车牌
    
    sign, roi, labels, card_color = 0,0,0,0

    colors = []
    for card_index,card_img in enumerate(card_imgs):
        green = yello = blue = black = white = 0
        try:
            card_img_hsv = cv2.cvtColor(card_img, cv2.COLOR_BGR2HSV)
        except BaseException:
            continue
        #有转换失败的可能，原因来自于上面矫正矩形出错
        if card_img_hsv is None:
            continue
        row_num, col_num= card_img_hsv.shape[:2]
        card_img_count = row_num * col_num

        temp_ = 0
        for i in range(row_num):
            for j in range(col_num):
                H = card_img_hsv.item(i, j, 0)
                S = card_img_hsv.item(i, j, 1)
                V = card_img_hsv.item(i, j, 2)
                if 11 < H <= 34 and S > 34:#图片分辨率调整
                    yello += 1
                elif 35 < H <= 99 and S > 34:#图片分辨率调整
                    green += 1
                elif 99 < H <= 124 and S > 34:#图片分辨率调整
                    blue += 1
                
                if 0 < H <180 and 0 < S < 255 and 0 < V < 46:
                    black += 1
                elif 0 < H <180 and 0 < S < 43 and 221 < V < 225:
                    white += 1
        color = "no"

        limit1 = limit2 = 0
        if yello*2 >= card_img_count:
            color = "yello"
            limit1 = 11
            limit2 = 34#有的图片有色偏偏绿
        elif green*2 >= card_img_count:
            color = "green"
            limit1 = 35
            limit2 = 99
        elif blue*2 >= card_img_count:
            color = "blue"
            limit1 = 100
            limit2 = 124#有的图片有色偏偏紫
        elif black + white >= card_img_count*0.7: #TODO
            color = "bw"
        # print("[ INFO ] color: {}".format(color))
        colors.append(color)
        # print(blue, green, yello, black, white, card_img_count)
        #cv2.imshow("color", card_img)
        #cv2.waitKey(0)a
        if limit1 == 0:
            continue
        #以上为确定车牌颜色

        #以下为根据车牌颜色再定位，缩小边缘非车牌边界
        xl, xr, yh, yl = accurate_place(card_img_hsv, limit1, limit2, color,cfg)
        if yl == yh and xl == xr:
            continue
        need_accurate = False
        if yl >= yh:
            yl = 0
            yh = row_num
            need_accurate = True
        if xl >= xr:
            xl = 0
            xr = col_num
            need_accurate = True
        card_imgs[card_index] = card_img[yl:yh, xl:xr] if color != "green" or yl < (yh-yl)//4 else card_img[yl-(yh-yl)//4:yh, xl:xr]
        if need_accurate:#可能x或y方向未缩小，需要再试一次
            card_img = card_imgs[card_index]
            card_img_hsv = cv2.cvtColor(card_img, cv2.COLOR_BGR2HSV)
            xl, xr, yh, yl = accurate_place(card_img_hsv, limit1, limit2, color,cfg)
            if yl == yh and xl == xr:
                continue
            if yl >= yh:
                yl = 0
                yh = row_num
            if xl >= xr:
                xl = 0
                xr = col_num
        card_imgs[card_index] = card_img[yl:yh, xl:xr] if color != "green" or yl < (yh-yl)//4 else card_img[yl-(yh-yl)//4:yh, xl:xr]
        cv2.imwrite("./temp/seg_card2.jpg", card_img)
        sign = 1
        roi = card_img
        card_color = color
        labels = (int(right_point[1]), int(heigth_point[1]), int(left_point[0]), int(right_point[0]))
    print('look:  ', sign, roi, labels, card_color)
    return sign, roi, labels, card_color#定位的车牌图像、车牌颜色

if __name__ == '__main__':
    for pic_file in os.listdir("./test_img"):

        roi, label,color = CaridDetect(os.path.join("./test_img",pic_file))
        cv2.imwrite(os.path.join("./result",pic_file),roi)
        print("*"*50)
        print("[ ROI ] {}".format(roi))
        print("[ Color ] {}".format(color))
        print("[ Label ] {}".format(label))