saliencyDetectionHou.cpp

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//===================================================================================
// Name        : saliencyDetectionHou.cpp
// Author      : Oytun Akman, oytunakman@gmail.com
// Editor          : Joris van de Weem, joris.vdweem@gmail.com (Conversion to ROS)
// Version     : 1.2
// Copyright   : Copyright (c) 2010 LGPL
// Description : C++ implementation of "Saliency Detection: A Spectral Residual 
//                               Approach" by Xiaodi Hou and Liqing Zhang (CVPR 2007).                                                                                            
//===================================================================================
// v1.1: Changed Gaussianblur of logamplitude to averaging blur and gaussian kernel of saliency map to sigma = 8, kernelsize = 5
//      for better consistency with the paper. (Joris)
// v1.2: Ported to Robot Operating System (ROS) (Joris)

#include <saliency_detection/saliencyDetectionHou.h>


void saliencyMapHou::imageCB(const sensor_msgs::ImageConstPtr& msg_ptr)
{
        cv_bridge::CvImagePtr cv_ptr;
        sensor_msgs::Image salmap_;
        geometry_msgs::Point salientpoint_;

        Mat image_, saliencymap_;
        Point pt_salient;
        double maxVal;

        try
        {
                cv_ptr = cv_bridge::toCvCopy(msg_ptr, enc::BGR8);
        }
        catch (cv_bridge::Exception& e)
        {
                ROS_ERROR("cv_bridge exception: %s", e.what());
        }
        cv_ptr->image.copyTo(image_);

        saliencymap_.create(image_.size(),CV_8UC1);
        saliencyMapHou::calculateSaliencyMap(&image_, &saliencymap_);

        //-- Return most salient point --//
        cv::minMaxLoc(saliencymap_,NULL,&maxVal,NULL,&pt_salient);
        salientpoint_.x = pt_salient.x;
        salientpoint_.y = pt_salient.y;


        //      CONVERT FROM CV::MAT TO ROSIMAGE FOR PUBLISHING
        saliencymap_.convertTo(saliencymap_, CV_8UC1,255);
        fillImage(salmap_, "mono8",saliencymap_.rows, saliencymap_.cols, saliencymap_.step, const_cast<uint8_t*>(saliencymap_.data));

        saliencymap_pub_.publish(salmap_);
        point_pub_.publish(salientpoint_);

        return;
}


void saliencyMapHou::calculateSaliencyMap(const Mat* src, Mat* dst)
{
        Mat grayTemp, grayDown;
        vector<Mat> mv; 
        //Size imageSize(160,120);
        Size imageSize(64,64);
        Mat realImage(imageSize,CV_64F);
        Mat imaginaryImage(imageSize,CV_64F); imaginaryImage.setTo(0);
        Mat combinedImage(imageSize,CV_64FC2);
        Mat imageDFT;   
        Mat logAmplitude;
        Mat angle(imageSize,CV_64F);
        Mat magnitude(imageSize,CV_64F);
        Mat logAmplitude_blur;
        
        cvtColor(*src, grayTemp, CV_BGR2GRAY);
        resize(grayTemp, grayDown, imageSize, 0, 0, INTER_LINEAR);
        for(int j=0; j<grayDown.rows;j++)
        for(int i=0; i<grayDown.cols; i++)
                realImage.at<double>(j,i) = grayDown.at<uchar>(j,i);
                        
        mv.push_back(realImage);
        mv.push_back(imaginaryImage);   
        merge(mv,combinedImage);        
        dft( combinedImage, imageDFT);
        split(imageDFT, mv);    

        //-- Get magnitude and phase of frequency spectrum --//
        cartToPolar(mv.at(0), mv.at(1), magnitude, angle, false);
        log(magnitude,logAmplitude);    
        //-- Blur log amplitude with averaging filter --//
        blur(logAmplitude, logAmplitude_blur, Size(3,3), Point(-1,-1), BORDER_DEFAULT);
        
        exp(logAmplitude - logAmplitude_blur,magnitude);
        //-- Back to cartesian frequency domain --//
        polarToCart(magnitude, angle, mv.at(0), mv.at(1), false);
        merge(mv, imageDFT);
        dft( imageDFT, combinedImage, CV_DXT_INVERSE); 
        split(combinedImage, mv);

        cartToPolar(mv.at(0), mv.at(1), magnitude, angle, false);
        GaussianBlur(magnitude, magnitude, Size(5,5), 8, 0, BORDER_DEFAULT);
        magnitude = magnitude.mul(magnitude);

        double minVal,maxVal;
        minMaxLoc(magnitude, &minVal, &maxVal);
        magnitude = magnitude / maxVal;

        Mat tempFloat(imageSize,CV_32F);
        for(int j=0; j<magnitude.rows;j++)
        for(int i=0; i<magnitude.cols; i++)
                tempFloat.at<float>(j,i) = magnitude.at<double>(j,i);

        resize(tempFloat, *dst, dst->size(), 0, 0, INTER_LINEAR);
}

int main(int argc, char **argv)
{
        ros::init(argc, argv, "saliencymap");

        saliencyMapHou salmapHou;

        ros::spin();

        return 0;
}