OpenCV/opencv_contrib/modules/ximgproc/samples/deriche_demo.cpp

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#include <opencv2/core.hpp>
#include <opencv2/core/utility.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/ximgproc.hpp>
#include "opencv2/ximgproc/deriche_filter.hpp"

using namespace cv;
using namespace cv::ximgproc;

#include <iostream>
using namespace std;

int alDerive=100;
int alMean=100;
Ptr<Mat> img;
const string & winName = "Gradient Modulus";

static void DisplayImage(Mat x,string s)
{
	vector<Mat> sx;
	split(x, sx);
	vector<double> minVal(3), maxVal(3);
	for (size_t i = 0; i < sx.size(); i++)
	{
		minMaxLoc(sx[i], &minVal[i], &maxVal[i]);
	}
	maxVal[0] = *max_element(maxVal.begin(), maxVal.end());
	minVal[0] = *min_element(minVal.begin(), minVal.end());
	Mat uc;
	x.convertTo(uc, CV_8U,255/(maxVal[0]-minVal[0]),-255*minVal[0]/(maxVal[0]-minVal[0]));
	imshow(s, uc);
}


/**
 * @function DericheFilter
 * @brief Trackbar callback
 */
static void DericheFilter(int, void*)
{
    Mat dst;
    double d=alDerive/100.0,m=alMean/100.0;
    Mat rx,ry;
    GradientDericheX(*img.get(),rx,d,m);
    GradientDericheY(*img.get(),ry,d,m);
    DisplayImage(rx, "Gx");
    DisplayImage(ry, "Gy");
    add(rx.mul(rx),ry.mul(ry),dst);
    sqrt(dst,dst);
    DisplayImage(dst, winName );
}

int main(int argc, char* argv[])
{
    Mat *m=new Mat;
    cv::CommandLineParser parser(argc, argv, "{help h | | show help message}{@input | | input image}");
    if (parser.has("help"))
    {
        parser.printMessage();
        return -1;
    }
    string input_image = parser.get<string>("@input");
    if (input_image.empty())
    {
        parser.printMessage();
        parser.printErrors();
        return -2;
    }
    if (argc==2)
        *m = imread(input_image);
    if (m->empty())
    {
        cout << "File not found or empty image\n";
        return -3;
    }
    imshow("Original", *m);
    img =Ptr<Mat>(m);
    namedWindow( winName, WINDOW_AUTOSIZE );
    /// Create a Trackbar for user to enter threshold
    createTrackbar( "Derive:",winName, &alDerive, 400, DericheFilter );
    createTrackbar( "Mean:", winName, &alMean, 400, DericheFilter );
    DericheFilter(0,NULL);
    waitKey();
    return 0;
}