I am trying to use opencv EM algorithm library.
I tried some example about EM algorithm such like this and this first, but I got the same problem in these code. It take me lots of time in EM training step.
This is my testing code for image segmentation from this website:
#include <opencv2/opencv.hpp>
#include <opencv2/legacy/legacy.hpp>
using namespace std;
using namespace cv;
Mat asSamplesVectors(Mat& img);
/** @function main */
int main(int argc, char** argv)
{
Mat image; int no_of_clusters = 2;
image = imread("images/flower.jpg");
Mat samples = asSamplesVectors(image);
cout << "Starting EM training" << endl;
EM em(no_of_clusters);
em.train(samples);
cout << "Finished training EM" << endl;
vector<Mat> segmented;
for (int i = 0; i < no_of_clusters; i++)
segmented.push_back(Mat::zeros(image.rows, image.cols, CV_8UC3));
int index = 0;
for (int y = 0; y < image.rows; y++) {
for (int x = 0; x < image.cols; x++) {
int result = em.predict(samples.row(index++))[1];
segmented[result].at<Point3i>(y, x, 0) = image.at<Point3i>(y, x, 0);
}
}
imshow("result", samples);
return(0);
}
Mat asSamplesVectors(Mat& img) {
Mat float_img;
img.convertTo(float_img, CV_32F);
Mat samples(img.rows * img.cols, 3, CV_32FC1);
/* Flatten */
int index = 0;
for (int y = 0; y < img.rows; y++) {
Vec3f* row = float_img.ptr<Vec3f>(y);
for (int x = 0; x < img.cols; x++)
samples.at<Vec3f>(index++, 0) = row[x];
}
return samples;
}
I test in VS2013, opencv 2.4.9 and opencv 2.4.11.
This is my testing image.
In this code, it show me the error message.
The error step is segmented[result].at<Point3i>(y, x, 0) = image.at<Point3i>(y, x, 0);
My first question is: why the EM training so slowly. Is it normally?
Second question is: what's wrong with my code error and is there any better example to let me know the usage of EM?
