# -*- coding: utf-8 -*-"""图像直方图反向投影如果一幅图像的区域中显示的是一种结构纹理或者一个独特的物体，那么这个区域的直方图可以看作一个概率函数，它给的是某个像素属于该纹理或物体的概率。所谓反向投影就是首先计算某一特征的直方图模型，然后使用模型去寻找测试图像中存在的该特征。"""import cv2import numpy as npfrom matplotlib import pyplot as pltimg = cv2.imread('../../../../datas/images/fish-target.jpg')hsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV)target = cv2.imread('../../../../datas/images/fish.jpg')hsvt = cv2.cvtColor(target,cv2.COLOR_BGR2HSV)roihist = cv2.calcHist([hsv],[0, 1], None, [180, 256], [0, 180, 0, 256] )cv2.normalize(roihist,roihist,0,255,cv2.NORM_MINMAX)dst = cv2.calcBackProject([hsvt],[0,1],roihist,[0,180,0,256],1)disc = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(5,5))cv2.filter2D(dst,-1,disc,dst)dst2 = dst.copy()ret,thresh = cv2.threshold(dst,50,255,0)thresh = cv2.merge((dst,dst,dst))dst2 = cv2.merge((dst,dst,dst))res = cv2.bitwise_and(target,thresh)res = np.vstack((target,dst2,res))#cv2.imwrite('res.jpg',res)cv2.imshow("result",res)cv2.waitKey()cv2.destroyAllWindows()