kmeans.cpp
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#include <stim/image/image.h>
//#include <cmath>
#include <stim/visualization/colormap.h>
#include <stim/image/image_contour_detection.h>
#include <opencv2/opencv.hpp>
#include <iostream>
/// This function use cvkmeans to cluster given textons
/// @param testons is a multi-channel image
/// @param k is the number of clusters
stim::image<float> kmeans(stim::image<float> textons, unsigned int K){
unsigned int w = textons.width(); // get the width of picture
unsigned int h = textons.height(); // get the height of picture
unsigned int feature_n = textons.channels(); // get the spectrum of picture
unsigned int N = w * h; // get the number of pixels
float* sample1 = (float*) malloc(sizeof(float) * N * feature_n); //allocate the space for textons
//reallocate a multi-channel texton image to a single-channel image
for(unsigned int c = 0; c < feature_n; c++){
stim::image<float> temp;
temp = textons.channel(c);
for(unsigned int j = 0; j < N; j++){
sample1[c + j * feature_n] = temp.data()[j];
}
}
cv::Mat sample2(N, feature_n, CV_32F, sample1); //copy image to cv::mat
//(optional) show the test result
//imshow("sample2", sample2);
cv::TermCriteria criteria(CV_TERMCRIT_EPS+CV_TERMCRIT_ITER, 10, 0.1); // set stop-criteria for kmeans iteration
cv::Mat labels(N, 1, CV_8U, cvScalarAll(0)); // allocate space for kmeans output
cv::Mat centers; // allocate space for kmeans output
unsigned int test_times = 2; // set the number of times of trying kmeans, it will return the best result
cv::kmeans(sample2, K, labels, criteria, test_times, cv::KMEANS_PP_CENTERS, centers); // kmeans clustering
//(optional) show the test result
//imwrite( "data_output/labels_1D.bmp", labels);
stim::image<float> texture(w, h, 1, 1); // allocate space for texture
for(unsigned int i = 0; i < N; i++){ // reshape the labels from iD array to image
texture.data()[i] = labels.at<int>(i);
}
//texture.save("data_output/kmeans_test0924_2.bmp");
//(optional) show the test result
//stim::cpu2image(texture.data(), "data_output/kmeans_test.bmp", w, h, stim::cmBrewer);
return texture;
}