opencv2 学习第8天 提取分离前景和背景

http://blog.csdn.net/zhouzhouzf/article/details/9281327

GrabCut

代码来自于http://www.cnblogs.com/tornadomeet/archive/2012/11/09/2763271.html

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/core.hpp>
#include <vector>
#include <iostream>
#include <opencv2/imgproc/imgproc.hpp>
//#include "../../../../../Downloads/colourhistogram.h"
using namespace std;
using namespace cv;
static void help()
{
    cout << "
This program demonstrates GrabCut segmentation -- select an object in a region
"
        "and then grabcut will attempt to segment it out.
"
        "Call:
"
        "./grabcut <image_name>
"
        "
Select a rectangular area around the object you want to segment
" <<
        "
Hot keys: 
"
        "	ESC - quit the program
"
        "	r - restore the original image
"
        "	n - next iteration
"
        "
"
        "	left mouse button - set rectangle
"
        "
"
        "	CTRL+left mouse button - set GC_BGD pixels
"
        "	SHIFT+left mouse button - set CG_FGD pixels
"
        "
"
        "	CTRL+right mouse button - set GC_PR_BGD pixels
"
        "	SHIFT+right mouse button - set CG_PR_FGD pixels
" << endl;
}

const Scalar RED = Scalar(0,0,255);
const Scalar PINK = Scalar(230,130,255);
const Scalar BLUE = Scalar(255,0,0);
const Scalar LIGHTBLUE = Scalar(255,255,160);
const Scalar GREEN = Scalar(0,255,0);

const int BGD_KEY = CV_EVENT_FLAG_CTRLKEY;  //Ctrl键
const int FGD_KEY = CV_EVENT_FLAG_SHIFTKEY; //Shift键

static void getBinMask( const Mat& comMask, Mat& binMask )
{
    if( comMask.empty() || comMask.type()!=CV_8UC1 )
        CV_Error( CV_StsBadArg, "comMask is empty or has incorrect type (not CV_8UC1)" );
    if( binMask.empty() || binMask.rows!=comMask.rows || binMask.cols!=comMask.cols )
        binMask.create( comMask.size(), CV_8UC1 );
    binMask = comMask & 1;  //得到mask的最低位,实际上是只保留确定的或者有可能的前景点当做mask
}

class GCApplication
{
public:
    enum{ NOT_SET = 0, IN_PROCESS = 1, SET = 2 };
    static const int radius = 2;
    static const int thickness = -1;

    void reset();
    void setImageAndWinName( const Mat& _image, const string& _winName );
    void showImage() const;
    void mouseClick( int event, int x, int y, int flags, void* param );
    int nextIter();
    int getIterCount() const { return iterCount; }
private:
    void setRectInMask();
    void setLblsInMask( int flags, Point p, bool isPr );

    const string* winName;
    const Mat* image;
    Mat mask;
    Mat bgdModel, fgdModel;

    uchar rectState, lblsState, prLblsState;
    bool isInitialized;

    Rect rect;
    vector<Point> fgdPxls, bgdPxls, prFgdPxls, prBgdPxls;
    int iterCount;
};

/*给类的变量赋值*/
void GCApplication::reset()
{
    if( !mask.empty() )
        mask.setTo(Scalar::all(GC_BGD));
    bgdPxls.clear(); fgdPxls.clear();
    prBgdPxls.clear();  prFgdPxls.clear();

    isInitialized = false;
    rectState = NOT_SET;    //NOT_SET == 0
    lblsState = NOT_SET;
    prLblsState = NOT_SET;
    iterCount = 0;
}

/*给类的成员变量赋值而已*/
void GCApplication::setImageAndWinName( const Mat& _image, const string& _winName  )
{
    if( _image.empty() || _winName.empty() )
        return;
    image = &_image;
    winName = &_winName;
    mask.create( image->size(), CV_8UC1);
    reset();
}

/*显示4个点，一个矩形和图像内容，因为后面的步骤很多地方都要用到这个函数，所以单独拿出来*/
void GCApplication::showImage() const
{
    if( image->empty() || winName->empty() )
        return;

    Mat res;
    Mat binMask;
    if( !isInitialized )
        image->copyTo( res );
    else
    {
        getBinMask( mask, binMask );
        image->copyTo( res, binMask );  //按照最低位是0还是1来复制，只保留跟前景有关的图像，比如说可能的前景，可能的背景
    }

    vector<Point>::const_iterator it;
    /*下面4句代码是将选中的4个点用不同的颜色显示出来*/
    for( it = bgdPxls.begin(); it != bgdPxls.end(); ++it )  //迭代器可以看成是一个指针
        circle( res, *it, radius, BLUE, thickness );
    for( it = fgdPxls.begin(); it != fgdPxls.end(); ++it )  //确定的前景用红色表示
        circle( res, *it, radius, RED, thickness );
    for( it = prBgdPxls.begin(); it != prBgdPxls.end(); ++it )
        circle( res, *it, radius, LIGHTBLUE, thickness );
    for( it = prFgdPxls.begin(); it != prFgdPxls.end(); ++it )
        circle( res, *it, radius, PINK, thickness );

    /*画矩形*/
    if( rectState == IN_PROCESS || rectState == SET )
        rectangle( res, Point( rect.x, rect.y ), Point(rect.x + rect.width, rect.y + rect.height ), GREEN, 2);

    imshow( *winName, res );
}

/*该步骤完成后，mask图像中rect内部是3，外面全是0*/
void GCApplication::setRectInMask()
{
    assert( !mask.empty() );
    mask.setTo( GC_BGD );   //GC_BGD == 0
    rect.x = max(0, rect.x);
    rect.y = max(0, rect.y);
    rect.width = min(rect.width, image->cols-rect.x);
    rect.height = min(rect.height, image->rows-rect.y);
    (mask(rect)).setTo( Scalar(GC_PR_FGD) );    //GC_PR_FGD == 3，矩形内部,为可能的前景点
}

void GCApplication::setLblsInMask( int flags, Point p, bool isPr )
{
    vector<Point> *bpxls, *fpxls;
    uchar bvalue, fvalue;
    if( !isPr ) //确定的点
    {
        bpxls = &bgdPxls;
        fpxls = &fgdPxls;
        bvalue = GC_BGD;    //0
        fvalue = GC_FGD;    //1
    }
    else    //概率点
    {
        bpxls = &prBgdPxls;
        fpxls = &prFgdPxls;
        bvalue = GC_PR_BGD; //2
        fvalue = GC_PR_FGD; //3
    }
    if( flags & BGD_KEY )
    {
        bpxls->push_back(p);
        circle( mask, p, radius, bvalue, thickness );   //该点处为2
    }
    if( flags & FGD_KEY )
    {
        fpxls->push_back(p);
        circle( mask, p, radius, fvalue, thickness );   //该点处为3
    }
}

/*鼠标响应函数，参数flags为CV_EVENT_FLAG的组合*/
void GCApplication::mouseClick( int event, int x, int y, int flags, void* )
{
    // TODO add bad args check
    switch( event )
    {
    case CV_EVENT_LBUTTONDOWN: // set rect or GC_BGD(GC_FGD) labels
        {
            bool isb = (flags & BGD_KEY) != 0,
                isf = (flags & FGD_KEY) != 0;
            if( rectState == NOT_SET && !isb && !isf )//只有左键按下时
            {
                rectState = IN_PROCESS; //表示正在画矩形
                rect = Rect( x, y, 1, 1 );
            }
            if ( (isb || isf) && rectState == SET ) //按下了alt键或者shift键，且画好了矩形，表示正在画前景背景点
                lblsState = IN_PROCESS;
        }
        break;
    case CV_EVENT_RBUTTONDOWN: // set GC_PR_BGD(GC_PR_FGD) labels
        {
            bool isb = (flags & BGD_KEY) != 0,
                isf = (flags & FGD_KEY) != 0;
            if ( (isb || isf) && rectState == SET ) //正在画可能的前景背景点
                prLblsState = IN_PROCESS;
        }
        break;
    case CV_EVENT_LBUTTONUP:
        if( rectState == IN_PROCESS )
        {
            rect = Rect( Point(rect.x, rect.y), Point(x,y) );   //矩形结束
            rectState = SET;
            setRectInMask();
            assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() );
            showImage();
        }
        if( lblsState == IN_PROCESS )   //已画了前后景点
        {
            setLblsInMask(flags, Point(x,y), false);    //画出前景点
            lblsState = SET;
            showImage();
        }
        break;
    case CV_EVENT_RBUTTONUP:
        if( prLblsState == IN_PROCESS )
        {
            setLblsInMask(flags, Point(x,y), true); //画出背景点
            prLblsState = SET;
            showImage();
        }
        break;
    case CV_EVENT_MOUSEMOVE:
        if( rectState == IN_PROCESS )
        {
            rect = Rect( Point(rect.x, rect.y), Point(x,y) );
            assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() );
            showImage();    //不断的显示图片
        }
        else if( lblsState == IN_PROCESS )
        {
            setLblsInMask(flags, Point(x,y), false);
            showImage();
        }
        else if( prLblsState == IN_PROCESS )
        {
            setLblsInMask(flags, Point(x,y), true);
            showImage();
        }
        break;
    }
}

/*该函数进行grabcut算法，并且返回算法运行迭代的次数*/
int GCApplication::nextIter()
{
    if( isInitialized )
        //使用grab算法进行一次迭代，参数2为mask，里面存的mask位是：矩形内部除掉那些可能是背景或者已经确定是背景后的所有的点，且mask同时也为输出
        //保存的是分割后的前景图像
        grabCut( *image, mask, rect, bgdModel, fgdModel, 1 );
    else
    {
        if( rectState != SET )
            return iterCount;

        if( lblsState == SET || prLblsState == SET )
            grabCut( *image, mask, rect, bgdModel, fgdModel, 1, GC_INIT_WITH_MASK );
        else
            grabCut( *image, mask, rect, bgdModel, fgdModel, 1, GC_INIT_WITH_RECT );

        isInitialized = true;
    }
    iterCount++;

    bgdPxls.clear(); fgdPxls.clear();
    prBgdPxls.clear(); prFgdPxls.clear();

    return iterCount;
}

GCApplication gcapp;

static void on_mouse( int event, int x, int y, int flags, void* param )
{
    gcapp.mouseClick( event, x, y, flags, param );
}

int main( int argc, char** argv )
{

    string filename = "D:\images\dog.jpg";
    Mat image = imread( filename, 1 );
    if( image.empty() )
    {
        cout << "
 Durn, couldn't read image filename " << filename << endl;
        return 1;
    }

    help();

    const string winName = "image";
    cvNamedWindow( winName.c_str(), CV_WINDOW_AUTOSIZE );
    cvSetMouseCallback( winName.c_str(), on_mouse, 0 );

    gcapp.setImageAndWinName( image, winName );
    gcapp.showImage();

    for(;;)
    {
        int c = cvWaitKey(0);
        switch( (char) c )
        {
        case 'x1b':
            cout << "Exiting ..." << endl;
            goto exit_main;
        case 'r':
            cout << endl;
            gcapp.reset();
            gcapp.showImage();
            break;
        case 'n':
            int iterCount = gcapp.getIterCount();
            cout << "<" << iterCount << "... ";
            int newIterCount = gcapp.nextIter();
            if( newIterCount > iterCount )
            {
                gcapp.showImage();
                cout << iterCount << ">" << endl;
            }
            else
                cout << "rect must be determined>" << endl;
            break;
        }
    }

exit_main:
    cvDestroyWindow( winName.c_str() );
    return 0;
}

opencv2 书本上给的GrabCut的方法代码，实现起来速度也是不太能够忍受

class WatershedSegmenter {

private:

    cv::Mat markers;

public:

    void setMarkers(const cv::Mat& markerImage) {

        // Convert to image of ints
        markerImage.convertTo(markers,CV_32S);
    }

    cv::Mat process(const cv::Mat &image) {

        // Apply watershed
        cv::watershed(image,markers);

        return markers;
    }

    // Return result in the form of an image
    cv::Mat getSegmentation() {

        cv::Mat tmp;
        // all segment with label higher than 255
        // will be assigned value 255
        markers.convertTo(tmp,CV_8U);

        return tmp;
    }

    // Return watershed in the form of an image
    cv::Mat getWatersheds() {

        cv::Mat tmp;
        markers.convertTo(tmp,CV_8U,255,255);

        return tmp;
    }
};
int main()
{
    using namespace cv;
    // Open another image
    Mat image= cv::imread("D:\images\tower.jpg");

    // define bounding rectangle
    cv::Rect rectangle(50,70,image.cols-150,image.rows-180);

    cv::Mat result; // segmentation result (4 possible values)
    cv::Mat bgModel,fgModel; // the models (internally used)
    // GrabCut segmentation
    cv::grabCut(image,    // input image
        result,   // segmentation result
        rectangle,// rectangle containing foreground
        bgModel,fgModel, // models
        1,        // number of iterations
        cv::GC_INIT_WITH_RECT); // use rectangle

    // Get the pixels marked as likely foreground
    cv::compare(result,cv::GC_PR_FGD,result,cv::CMP_EQ);
    // Generate output image
    cv::Mat foreground(image.size(),CV_8UC3,cv::Scalar(255,255,255));
    image.copyTo(foreground,result); // bg pixels not copied

    // draw rectangle on original image
    cv::rectangle(image, rectangle, cv::Scalar(255,255,255),1);
    cv::namedWindow("Image");
    cv::imshow("Image",image);

    // display result
    cv::namedWindow("Segmented Image");
    cv::imshow("Segmented Image",foreground);

    // Open another image
    image= cv::imread("D:\images\tower.jpg");

    // define bounding rectangle
    cv::Rect rectangle2(10,100,380,180);

    cv::Mat bkgModel,fgrModel; // the models (internally used)
    // GrabCut segmentation
    cv::grabCut(image,  // input image
        result, // segmentation result
        rectangle2,bkgModel,fgrModel,5,cv::GC_INIT_WITH_RECT);
    // Get the pixels marked as likely foreground
    //      cv::compare(result,cv::GC_PR_FGD,result,cv::CMP_EQ);
    result= result&1;
    foreground.create(image.size(),CV_8UC3);
    foreground.setTo(cv::Scalar(255,255,255));
    image.copyTo(foreground,result); // bg pixels not copied

    // draw rectangle on original image
    cv::rectangle(image, rectangle2, cv::Scalar(255,255,255),1);
    cv::namedWindow("Image 2");
    cv::imshow("Image 2",image);

    // display result
    cv::namedWindow("Foreground objects");
    cv::imshow("Foreground objects",foreground);
    waitKey(0);
    system("pause");
    return 0;
}

 

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