opencv学习-imgprocess-反向投影Back Projection

opencv中计算Back Projection的函数为calcBackProject，mixChannels是用来从输入中拷贝某通道到输出中特定的通道。

还是以例子说明

(1)例如灰度图像如下

Image=

  0    1    2    3

  4    5    6    7

  8    9   10   11

  8    9   14   15

(2)该灰度图的直方图为（bin指定的区间为[0,3)，[4,7)，[8,11)，[12,16)）

Histogram=

  4    4    6    2

(3)反向投影图

Back_Projection=

  4    4    4    4

  4    4    4    4

  6    6    6    6

  6    6    2    2

例如位置(0,0)上的像素值为0，对应的bin为[0,3)，所以反向直方图在该位置上的值这个bin的值4。

代码如下：

老版本:

#include <cv.h>  #include <highgui.h>   #include"stdio.h"int main(){ IplImage*src= cvLoadImage("hand.jpg", 1);    IplImage*templ=cvLoadImage("part.jpg",1); cvNamedWindow( "Source" );       cvShowImage( "Source", src );      IplImage* h_plane2 = cvCreateImage( cvGetSize(src), 8, 1 );          IplImage* s_plane2 = cvCreateImage( cvGetSize(src), 8, 1 );        IplImage* v_plane2 = cvCreateImage( cvGetSize(src), 8, 1);     IplImage* planes2[] = { h_plane2, s_plane2,v_plane2 };          IplImage* hsv2 = cvCreateImage( cvGetSize(src), 8, 3 );    cvCvtColor( src, hsv2, CV_BGR2HSV );         cvSplit( hsv2, h_plane2, s_plane2, v_plane2, 0 );      printf("h%d",h_plane2->widthStep);      printf("s%d",h_plane2->widthStep);    printf("v%d",h_plane2->widthStep);      IplImage* h_plane = cvCreateImage( cvGetSize(templ), 8, 1 );          IplImage* s_plane = cvCreateImage( cvGetSize(templ), 8, 1 );        IplImage* v_plane = cvCreateImage( cvGetSize(templ), 8, 1);        IplImage* planes[] = { h_plane, s_plane,v_plane };    IplImage* hsv = cvCreateImage( cvGetSize(templ), 8, 3 );        cvCvtColor( templ, hsv, CV_BGR2HSV );          cvSplit( hsv, h_plane, s_plane, v_plane, 0 );     printf("h%d\n",h_plane->widthStep);     printf("s%d\n",s_plane->widthStep);      printf("v%d\n",v_plane->widthStep);     int h_bins = 30, s_bins = 32,v_bins=32;     int hist_size[] = {h_bins, s_bins,v_bins};     float h_ranges[] = { 0, 180 };    float s_ranges[]={0,255};    float v_ranges[]={0,255};     float* ranges[] = { h_ranges, s_ranges,v_ranges};      CvHistogram* hist;      hist = cvCreateHist( 3, hist_size, CV_HIST_ARRAY, ranges, 1 );        cvCalcHist( planes, hist, 0, 0 );       //1.double a=1.f;   //2.cvNormalizeHist(hist,a);   //templ's hist is just calculate   IplImage*back_project=cvCreateImage(cvGetSize(src),8,1);//!!归一，把8改成32，就弹出对话框，说planes的steps不是一致的！      cvZero(back_project);                                   //但是我去掉归一，改成8就可以显示了。为什么浮点型不行呢？？？      //NOW we begin calculate back project   cvCalcBackProject(planes2,back_project,hist);        cvNamedWindow( "back_project" );       cvShowImage( "back_project", back_project );      cvWaitKey(0);  return 0;}

新版本

#include "opencv2/imgproc/imgproc.hpp"#include "opencv2/highgui/highgui.hpp"#include <iostream>using namespace cv;using namespace std;/// Global VariablesMat src; Mat hsv; Mat hue;vector<Mat>h_s_v;int bins = 25;/// Function Headersvoid Hist_and_Backproj(int, void* );/** @function main */int main( int argc, char** argv ){/// Read the imagesrc = imread("200.jpg", 1 );/// Transform it to HSVcvtColor( src, hsv, CV_BGR2HSV );/// Use only the Hue valuehue.create( hsv.size(), hsv.depth() );//int ch[] = { 0, 0 };//mixChannels( &hsv, 1, &hue, 1, ch, 1 );/// Create Trackbar to enter the number of binssplit(hsv,h_s_v);char* window_image = "Source image";namedWindow( window_image, CV_WINDOW_AUTOSIZE );createTrackbar("* Hue bins: ", window_image, &bins, 180, Hist_and_Backproj );Hist_and_Backproj(0, 0);/// Show the imageimshow( window_image, src );/// Wait until user exits the programwaitKey(0);return 0;}/*** @function Hist_and_Backproj* @brief Callback to Trackbar*/void Hist_and_Backproj(int, void* ){MatND hist;int histSize = MAX( bins, 2 );float hue_range[] = { 0, 180 };float s_range[] = { 0, 255 };const float* ranges = { hue_range,s };/// Get the Histogram and normalize itcalcHist( &hue, 1, 0, Mat(), hist, 1, &histSize, &ranges, true, false );normalize( hist, hist, 0, 255, NORM_MINMAX, -1, Mat() );/// Get BackprojectionMatND backproj;calcBackProject( &hue, 1, 0, hist, backproj, &ranges, 1, true );/// Draw the backprojimshow( "BackProj", backproj );/// Draw the histogramint w = 400; int h = 400;int bin_w = cvRound( (double) w / histSize );Mat histImg = Mat::zeros( w, h, CV_8UC3 );for( int i = 0; i < bins; i ++ ){ rectangle( histImg, Point( i*bin_w, h ), Point( (i+1)*bin_w, h - cvRound( hist.at<float>(i)*h/255.0 ) ), Scalar(0,0,255),1,8,0);}imshow( "Histogram", histImg );}