python+opencv实现二维码定位（二）

思路

1）二值化
2）膨胀与腐蚀
3）找到所有矩形并进行筛选(筛选过程可以加入上一篇文章)
4）对所有满足条件的矩形进行二维码检测

import cv2
import copy
import numpy as np
import pyzbar.pyzbar as pyzbar

def prethreatment(img0):
    
    #read img and copy

    img = copy.deepcopy(img0)
    ##cv2.imshow('img',img)

    #make img into gray
    gray=cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    ##cv2.imshow('gray',gray)

    #threshold
    ret,thre=cv2.threshold(gray,100,255,cv2.THRESH_BINARY)
    ##cv2.imshow('thre',thre)

    #erode
    kernel = np.ones((5,5),np.uint8)
    erosion = cv2.erode(thre,kernel)
    erosion = cv2.erode(erosion,kernel)
    
    #cv2.imshow('erosion',erosion)

    #findContours
    imgc,contours,hier=cv2.findContours(erosion,
                                       cv2.RETR_LIST,
                                       cv2.CHAIN_APPROX_SIMPLE)
    return contours,gray

def pick_rectangels(contours):
    
    #choosecontours
    rec = []
    for c in contours:
        x,y,w,h=cv2.boundingRect(c)#计算出一个简单地边界框
        if (abs(w-h)<10) & (w>50):
            rec.append([x,y,w,h])
    print(rec)
    return rec

def decode_qrcodes(rec,gray):
    
    for r in rec:
        x1 = r[0]
        x2 = r[0]+r[2]
        y1 = r[1]
        y2 = r[1]+r[3]
        print(x1,x2,y1,y2)
        
        img = gray[y1:y2,x1:x2]
        img = cv2.resize(img,(r[3]*2,r[2]*2))

        message = decode_qrcode(img)

        if message != -1:
            return message,img

def decode_qrcode(image):
    barcodes = pyzbar.decode(image)
    for barcode in barcodes:
        # 条形码数据为字节对象，所以如果我们想在输出图像上
        # 画出来，就需要先将它转换成字符串
        barcodeData = barcode.data.decode("utf-8")
        barcodeType = barcode.type
        # 提取条形码的边界框的位置
        # 画出图像中条形码的边界框
        #(x, y, w, h) = barcode.rect
        #cv2.rectangle(image, (x, y), (x + w, y + h), (0, 0, 255), 2)
        # 向终端打印条形码数据和条形码类型
        #print("[INFO] Found {} barcode: {}".format(barcodeType, barcodeData))
    try:
        return barcodeData
    except:
        return -1

if __name__=='__main__':

    imgpath = "cat.jpg"
    img0 = cv2.imread(imgpath)

    contours,gray = prethreatment(img0)
    rec = pick_rectangels(contours)

    message,img = decode_qrcodes(rec,gray)
    print(message)
    
    cv2.imshow('0',img0)
    cv2.imshow('1',img)
    
    cv2.waitKey(0)
    cv2.destroyAllWindows()

这端代码中没有加入错误检测，如果没有检测到二维码会报错，以后改进。