具体的算法原理可以参考：

PS滤镜，素描算法

// define head function

#ifndef PS_ALGORITHM_H_INCLUDED

#define PS_ALGORITHM_H_INCLUDED

#include <iostream>

#include <string>

#include "cv.h"

#include "highgui.h"

#include "cxmat.hpp"

#include "cxcore.hpp"

using namespace std;

using namespace cv;

void Show_Image(Mat&, const string &);

#endif // PS_ALGORITHM_H_INCLUDED

/*

This program will generate

 "Sketch" effect.

*/

#include "PS_Algorithm.h"

#include <time.h>

using namespace std;

using namespace cv;

int main(void)

{

    string Img_name("4.jpg");

    Mat Image_in;

    Image_in=imread(Img_name);

    // Show_Image(Image_in, Img_name);

    Mat Image_out(Image_in.size(), CV_32FC3);

    Image_in.convertTo(Image_out, CV_32FC3);

    Mat I(Image_in.size(), CV_32FC1);

    cv::cvtColor(Image_out, I, CV_BGR2GRAY);

    I=I/255.0;

    // Show_Image(I, "gray");

    Mat I_invert;

    I_invert=-I+1.0;

    // Show_Image(I_invert, "Inv");

    Mat I_gau;

    GaussianBlur(I_invert, I_gau, Size(25,25), 0, 0);

    //Show_Image(I_gau, "gau1");

    float delta=0.01;

    I_gau=-I_gau+1.0+delta;

    //Show_Image(I_gau, "gau");

    Mat I_dst;

    cv::divide(I, I_gau, I_dst);

    I_dst=I_dst;

    Show_Image(I_dst, "dst");

    Mat b(Image_in.size(), CV_32FC1);

    Mat g(Image_in.size(), CV_32FC1);

    Mat r(Image_in.size(), CV_32FC1);

    Mat rgb[]={b,g,r};

    float alpha=0.75;

    r=alpha*I_dst+(1-alpha)*200.0/255.0;

    g=alpha*I_dst+(1-alpha)*205.0/255.0;

    b=alpha*I_dst+(1-alpha)*105.0/255.0;

    cv::merge(rgb, 3, Image_out);

    Show_Image(Image_out, "out");

    imwrite("out.jpg", Image_out*255);

    waitKey();

    cout<<"All is well."<<endl;

}

// define the show image

#include "PS_Algorithm.h"

#include <iostream>

#include <string>

using namespace std;

using namespace cv;

void Show_Image(Mat& Image, const string& str)

{

    namedWindow(str.c_str(),CV_WINDOW_AUTOSIZE);

    imshow(str.c_str(), Image);

}

原图

效果图