import cv2 as cv
import numpy as np
from matplotlib import pyplot as pltdef back_projection_demo():sample = cv.imread("./Mat.png")# hist2d_demo(sample)target = cv.imread("./test.png")# hist2d_demo(target)roi_hsv = cv.cvtColor(sample, cv.COLOR_BGR2HSV)target_hsv = cv.cvtColor(target, cv.COLOR_BGR2HSV)# show imagescv.imshow("sample", sample)cv.imshow("target", target)roiHist = cv.calcHist([roi_hsv], [0, 1], None, [32, 32], [0, 180, 0, 256])cv.normalize(roiHist, roiHist, 0, 255, cv.NORM_MINMAX)dst = cv.calcBackProject([target_hsv], [0, 1], roiHist, [0, 180, 0, 256], 1)cv.imshow("backProjectionDemo", dst)def hist2d_demo(image):hsv = cv.cvtColor(image, cv.COLOR_BGR2HSV)hist = cv.calcHist([hsv], [0, 1], None, [32, 32], [0, 180, 0, 256])dst = cv.resize(hist, (400, 400))cv.imshow("image", image)cv.imshow("hist", dst)plt.imshow(hist, interpolation='nearest')plt.title("2D Histogram")plt.show()back_projection_demo()
cv.waitKey(0)cv.destroyAllWindows()

#include <opencv2/opencv.hpp>
#include <iostream>using namespace cv;
using namespace std;const int bins = 256;
Mat src;
const char* winTitle = "input image";
void backProjection_demo(Mat &image, Mat &model);
int main(int argc, char** argv) {Mat src = imread("./Mat.png");Mat model = imread("./test.png");if (src.empty() || model.empty()) {printf("could not load image...n");return 0;}namedWindow(winTitle, WINDOW_AUTOSIZE);imshow(winTitle, src);imshow("model", model);backProjection_demo(src, model);waitKey(0);return 0;
}void backProjection_demo(Mat &image, Mat &model) {Mat model_hsv, image_hsv;cvtColor(model, model_hsv, COLOR_BGR2HSV);cvtColor(image, image_hsv, COLOR_BGR2HSV);// ����ֱ��ͼ����������int h_bins = 32; int s_bins = 32;int histSize[] = { h_bins, s_bins };// hue varies from 0 to 179, saturation from 0 to 255float h_ranges[] = { 0, 180 };float s_ranges[] = { 0, 256 };const float* ranges[] = { h_ranges, s_ranges };int channels[] = { 0, 1 };Mat roiHist;calcHist(&model_hsv, 1, channels, Mat(), roiHist, 2, histSize, ranges, true, false);normalize(roiHist, roiHist, 0, 255, NORM_MINMAX, -1, Mat());MatND backproj;calcBackProject(&image_hsv, 1, channels, roiHist, backproj, ranges, 1.0);imshow("BackProj", backproj);
}