颜色直方图特征代码

颜色直方图比较简单，统计图像中的颜色分布。是个常用的全局特征，一般需要的话，可以加上SPM，能有效对空间位置进行编码。

代码如下：

[cpp] view
plaincopy





#include <sys/types.h>

#include <boost/filesystem.hpp>

#include "opencv2/core/core.hpp"

#include "opencv2/highgui/highgui.hpp"

#include "opencv2/nonfree/features2d.hpp"

#include "opencv2/imgproc/imgproc.hpp"

#include <boost/algorithm/string.hpp>

using namespace cv;

using namespace std;



void compute_colorfeatures(const string& imgPath, vector<float>& features) {

Mat mat = imread(imgPath);

Mat hsv_img;

cvtColor(mat, hsv_img, COLOR_BGR2HSV);

int h_bins = 30;

int s_bins = 50;

int histSize[] = { h_bins, s_bins };

// hue varies from 0 to 256, saturation from 0 to 180

float s_ranges[] = { 0, 256 };

float h_ranges[] = { 0, 180 };

const float* ranges[] = { h_ranges, s_ranges };

// Use the o-th and 1-st channels

int channels[] = { 0, 1 };

/// Histograms

MatND color_features;

/// Calculate the histograms for the HSV images

calcHist(&hsv_img, 1, channels, Mat(), color_features, 2, histSize, ranges,

true, false);

normalize(color_features, color_features, 0, 1, NORM_MINMAX, -1, Mat());

for (int i = 0; i < color_features.rows; i++) {

for (int j = 0; j < color_features.cols; j++) {

features.push_back(color_features.at<float>(i, j));

}

}

}