graphcutmex.cpp

Graph Cut algorithm implementation. Includes MATLAB compiled codes.

/* set user defined labels to graph */
void SetLabels(GCoptimization *MyGraph, int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    /* we need exactly 3 input arguments: gch, mode, labels */
    if (nrhs != 3 ) 
        mexErrMsgIdAndTxt("GraphCut:SetLabels","Wrong number of input arguments");
    if ( mxGetClassID(prhs[2]) != mxINT32_CLASS ) 
        mexErrMsgIdAndTxt("GraphCut:SetLabels","labels array not int32");
    if ( mxGetNumberOfElements(prhs[2]) != MyGraph->GetNumPixels() )
        mexErrMsgIdAndTxt("GraphCut:SetLabels","wrong number of elements in labels array");
    
    /* verify only one output parameter */
    if (nlhs != 1)
        mexErrMsgIdAndTxt("GraphCut:SetLabels","wrong number of output parameters");
    
    MyGraph->SetAllLabels( (GCoptimization::LabelType*) mxGetData(prhs[2]) );
}
/**************************************************************************************/
/* set user defined labels to graph */
void GetLabels(GCoptimization *MyGraph, int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    /* exactly two input arguments */
    if ( nrhs != 2 ) 
        mexErrMsgIdAndTxt("GraphCut:GetLabels","Wrong number of input arguments");
        
    /* we need exactly 2 output arguments: gch, labels */
    if (nlhs != 2 ) 
        mexErrMsgIdAndTxt("GraphCut:GetLabels","Wrong number of output arguments");
    int dims[2];

    /* transposed result */
    dims[0] = MyGraph->GetWidth();
    dims[1] = MyGraph->GetNumPixels() / dims[0];

    plhs[1] = mxCreateNumericArray(2, dims, mxINT32_CLASS, mxREAL);
    MyGraph->ExportLabels( (GCoptimization::LabelType*) mxGetData(plhs[1]) );
}
/**************************************************************************************/
/* support several kinds of a/b swaps:
 * 1. defualt - swap till convergence (no extra parameters)
 * 2. #iterations - performs #iterations:   GraphCut(gch, mode, #iteration)
 * 3. swap two labels - GraphCut(gch, mode, l1, l2)
 */
void ABswaps(GCoptimization *MyGraph, int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    int max_iterations(0), li(0);
    GCoptimization::LabelType label[2] = { 0, 1};
    GCoptimization::PixelType *indices = NULL;
    
    /* check inputs */
    switch (nrhs) {
        case 2:
            /* default - expand till convergence */
            MyGraph->swap();
            break;
        case 3:
            /* number of iterations */
            GetScalar(prhs[2], max_iterations);
            if ( max_iterations == 1 ) 
                MyGraph->oneSwapIteration();
            else
                MyGraph->swap(max_iterations);
            break;
        case 4:
            for ( li = 2; li<4;li++) {
                GetScalar(prhs[li], label[li-2]);
                if ( label[li-2] < 0 || label[li-2] >= MyGraph->GetNumLabels() ) 
                    mexErrMsgIdAndTxt("GraphCut:swap","invalid label value");
            }
            MyGraph->alpha_beta_swap(label[0], label[1]);
            break;
        default:
            mexErrMsgIdAndTxt("GraphCut:swap","Too many input arguments");
    }
        
    /* output: at least one (gch) can output the labels as well */
    if ( nlhs > 2 ) 
        mexErrMsgIdAndTxt("GraphCut:swap","too many output arguments");

    /* output labels */
    if ( nlhs >= 2 ) {
        /* set the lables */
        int dims[2];
        /* transposed result */
        dims[0] = MyGraph->GetWidth();
        dims[1] = MyGraph->GetNumPixels() / dims[0];
        
        plhs[1] = mxCreateNumericArray(2, dims, mxINT32_CLASS, mxREAL);
        MyGraph->ExportLabels( (GCoptimization::LabelType*) mxGetData(plhs[1]) );
    }
                    
}

/**************************************************************************************/
/* support several kinds of expansion 
 * 1. default - expand untill convergence no extra parameters
 * 2. #iterations - performs #iterations:   GraphCut(gch, mode, #iteration)
 * 3. expand label - expand specific label  GraphCut(gch, mode, [], label)
 * 4. expand label at specific indices      GraphCut(gch, mode, [], label, indices) indices start with zero and not 1 like usuall matlab inices!!
 */
void Expand(GCoptimization *MyGraph, int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{   
    int num(0), max_iterations(0);
    GCoptimization::LabelType label(0);
    GCoptimization::PixelType *indices = NULL;
    
    /* check inputs */
    switch (nrhs) {
        case 2:
            /* default - expand till convergence */
            MyGraph->expansion();
            break;
        case 3:
            /* number of iterations */
            GetScalar(prhs[2], max_iterations);
            if ( max_iterations == 1 ) 
                MyGraph->oneExpansionIteration();
            else
                MyGraph->expansion(max_iterations);
            break;
        case 5:
            /* get indices */
            if (mxGetClassID(prhs[4]) != mxINT32_CLASS)
                mexErrMsgIdAndTxt("GraphCut:Expand","indices must be int32");
            num = mxGetNumberOfElements(prhs[4]);
            if (num < 0 || num > MyGraph->GetNumPixels())
                mexErrMsgIdAndTxt("GraphCut:Expand","too many indices");
            indices = (GCoptimization::PixelType*)mxGetData(prhs[4]);
        case 4:
            /* expand specific label */
            if (mxGetNumberOfElements(prhs[2]) != 0)
                mexErrMsgIdAndTxt("GraphCut:Expand","third argument must empty");
            GetScalar(prhs[3], label);

            if ( indices != NULL ) {
                /* expand specific label at specific indices */
                MyGraph->alpha_expansion(label, indices, num);
            } else
                MyGraph->alpha_expansion(label);

            break;
        default:
            mexErrMsgIdAndTxt("GraphCut:Expand","Too many input arguments");
    }
        
    /* output: at least one (gch) can output the labels as well */
    if ( nlhs > 2 ) 
        mexErrMsgIdAndTxt("GraphCut:Expand","too many output arguments");

    /* output labels */
    if ( nlhs >= 2 ) {
        /* set the lables */
        int dims[2];
        /* transposed result */
        dims[0] = MyGraph->GetWidth();
        dims[1] = MyGraph->GetNumPixels() / dims[0];
        
        plhs[1] = mxCreateNumericArray(2, dims, mxINT32_CLASS, mxREAL);
        MyGraph->ExportLabels( (GCoptimization::LabelType*) mxGetData(plhs[1]) );

    }
}

/**************************************************************************************/
/* extract energy of labeling  
 * [gch se de] = GraphCut(gch, 'n');
 */
void Energy(GCoptimization *MyGraph, int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    if ( nrhs != 2 )
        mexErrMsgIdAndTxt("GraphCut:Energy","Too many input arguments");
    if ( nlhs != 3 )
        mexErrMsgIdAndTxt("GraphCut:Energy","wrong number of output arguments");
    
    int dims[2] = {1,0};
    GCoptimization::EnergyType *e;
    
    plhs[1] = mxCreateNumericArray(1, dims, mxSINGLE_CLASS, mxREAL);
    e = (GCoptimization::EnergyType *)mxGetData(plhs[1]);
    *e = MyGraph->giveSmoothEnergy();
    
    plhs[2] = mxCreateNumericArray(1, dims, mxSINGLE_CLASS, mxREAL);
    e = (GCoptimization::EnergyType *)mxGetData(plhs[2]);
    *e = MyGraph->giveDataEnergy();
}
/**************************************************************************************/
GCoptimization* GetGCHandle(const mxArray *x)
{
    GraphHandle gch = 0;
    GCoptimization* MyGraph = 0;
    
    if ( mxGetNumberOfElements(x) != 1 ) {
        mexErrMsgIdAndTxt("GraphCut:handle",
        "Too many GC handles");
    }
    if ( mxGetClassID(x) != MATLAB_POINTER_TYPE ) {
        mexErrMsgIdAndTxt("GraphCut:handle",
        "GC handle argument is not of proper type");
    }
    gch = (GraphHandle*)mxGetData(x);
    MyGraph = (GCoptimization*)(*(POINTER_CAST*)gch);
    if ( MyGraph==NULL || ! MyGraph->IsClassValid() ) {
        mexErrMsgIdAndTxt("GraphCut:handle",
        "GC handle is not valid");
    }

    
    return MyGraph;
}
/**************************************************************************************/