siox.cpp

/*
   Copyright 2005, 2006 by Gerald Friedland, Kristian Jantz and Lars Knipping

   Conversion to C++ for Inkscape by Bob Jamison

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
 */
#include "siox.h"

#include <math.h>
#include <stdarg.h>
#include <map>
#include <algorithm>


namespace org
{

namespace siox
{



//########################################################################
//#  C L A B
//########################################################################

/**
 * Convert integer A, R, G, B values into an pixel value.
 */
static unsigned long getRGB(int a, int r, int g, int b)
{
    if (a<0)  a=0;
    else if (a>255) a=255;

    if (r<0) r=0;
    else if (r>255) r=255;

    if (g<0) g=0;
    else if (g>255) g=255;

    if (b<0) b=0;
    else if (b>255) b=255;

    return (a<<24)|(r<<16)|(g<<8)|b;
}



/**
 * Convert float A, R, G, B values (0.0-1.0) into an pixel value.
 */
static unsigned long getRGB(float a, float r, float g, float b)
{
    return getRGB((int)(a * 256.0),
                  (int)(r * 256.0),
                  (int)(g * 256.0),
                  (int)(b * 256.0));
}



//#########################################
//# Root approximations for large speedup.
//# By njh!
//#########################################
static const int ROOT_TAB_SIZE = 16;
static float cbrt_table[ROOT_TAB_SIZE +1];

double CieLab::cbrt(double x)
{
    double y = cbrt_table[int(x*ROOT_TAB_SIZE )]; // assuming x \in [0, 1]
    y = (2.0 * y + x/(y*y))/3.0;
    y = (2.0 * y + x/(y*y))/3.0; // polish twice
    return y;
}

static float qn_table[ROOT_TAB_SIZE +1];

double CieLab::qnrt(double x)
{
    double y = qn_table[int(x*ROOT_TAB_SIZE )]; // assuming x \in [0, 1]
    double Y = y*y;
    y = (4.0*y + x/(Y*Y))/5.0;
    Y = y*y;
    y = (4.0*y + x/(Y*Y))/5.0; // polish twice
    return y;
}

double CieLab::pow24(double x)
{
    double onetwo = x*qnrt(x);
    return onetwo*onetwo;
}


static bool _clab_inited_ = false;
void CieLab::init()
{
    if (!_clab_inited_)
        {
        cbrt_table[0] = pow(float(1)/float(ROOT_TAB_SIZE*2), 0.3333);
        qn_table[0]   = pow(float(1)/float(ROOT_TAB_SIZE*2), 0.2);
        for(int i = 1; i < ROOT_TAB_SIZE +1; i++)
            {
            cbrt_table[i] = pow(float(i)/float(ROOT_TAB_SIZE), 0.3333);
            qn_table[i] = pow(float(i)/float(ROOT_TAB_SIZE), 0.2);
            }
        _clab_inited_ = true;
        }
}
      


/**
 * Construct this CieLab from a packed-pixel ARGB value
 */
CieLab::CieLab(unsigned long rgb)
{
    init();

    int ir  = (rgb>>16) & 0xff;
    int ig  = (rgb>> 8) & 0xff;
    int ib  = (rgb    ) & 0xff;

    float fr = ((float)ir) / 255.0;
    float fg = ((float)ig) / 255.0;
    float fb = ((float)ib) / 255.0;

    //printf("fr:%f fg:%f fb:%f\n", fr, fg, fb);
    if (fr > 0.04045)
        //fr = (float) pow((fr + 0.055) / 1.055, 2.4);
        fr = (float) pow24((fr + 0.055) / 1.055);
    else
        fr = fr / 12.92;

    if (fg > 0.04045)
        //fg = (float) pow((fg + 0.055) / 1.055, 2.4);
        fg = (float) pow24((fg + 0.055) / 1.055);
    else
        fg = fg / 12.92;

    if (fb > 0.04045)
        //fb = (float) pow((fb + 0.055) / 1.055, 2.4);
        fb = (float) pow24((fb + 0.055) / 1.055);
    else
        fb = fb / 12.92;

    // Use white = D65
    const float x = fr * 0.4124 + fg * 0.3576 + fb * 0.1805;
    const float y = fr * 0.2126 + fg * 0.7152 + fb * 0.0722;
    const float z = fr * 0.0193 + fg * 0.1192 + fb * 0.9505;

    float vx = x / 0.95047;
    float vy = y;
    float vz = z / 1.08883;

    //printf("vx:%f vy:%f vz:%f\n", vx, vy, vz);
    if (vx > 0.008856)
        //vx = (float) pow(vx, 0.3333);
        vx = (float) cbrt(vx);
    else
        vx = (7.787 * vx) + (16.0 / 116.0);

    if (vy > 0.008856)
        //vy = (float) pow(vy, 0.3333);
        vy = (float) cbrt(vy);
    else
        vy = (7.787 * vy) + (16.0 / 116.0);

    if (vz > 0.008856)
        //vz = (float) pow(vz, 0.3333);
        vz = (float) cbrt(vz);
    else
        vz = (7.787 * vz) + (16.0 / 116.0);

    C = 0;
    L = 116.0 * vy - 16.0;
    A = 500.0 * (vx - vy);
    B = 200.0 * (vy - vz);
}



/**
 * Return this CieLab's value converted to a packed-pixel ARGB value
 */
unsigned long CieLab::toRGB()
{
    float vy = (L + 16.0) / 116.0;
    float vx = A / 500.0 + vy;
    float vz = vy - B / 200.0;

    float vx3 = vx * vx * vx;
    float vy3 = vy * vy * vy;
    float vz3 = vz * vz * vz;

    if (vy3 > 0.008856)
        vy = vy3;
    else
        vy = (vy - 16.0 / 116.0) / 7.787;

    if (vx3 > 0.008856)
        vx = vx3;
    else
        vx = (vx - 16.0 / 116.0) / 7.787;

    if (vz3 > 0.008856)
        vz = vz3;
    else
        vz = (vz - 16.0 / 116.0) / 7.787;

    vx *= 0.95047; //use white = D65
    vz *= 1.08883;

    float vr =(float)(vx *  3.2406 + vy * -1.5372 + vz * -0.4986);
    float vg =(float)(vx * -0.9689 + vy *  1.8758 + vz *  0.0415);
    float vb =(float)(vx *  0.0557 + vy * -0.2040 + vz *  1.0570);

    if (vr > 0.0031308)
        vr = (float)(1.055 * pow(vr, (1.0 / 2.4)) - 0.055);
    else
        vr = 12.92 * vr;

    if (vg > 0.0031308)
        vg = (float)(1.055 * pow(vg, (1.0 / 2.4)) - 0.055);
    else
        vg = 12.92 * vg;

    if (vb > 0.0031308)
        vb = (float)(1.055 * pow(vb, (1.0 / 2.4)) - 0.055);
    else
        vb = 12.92 * vb;

    return getRGB(0.0, vr, vg, vb);
}


/**
 * Squared Euclidian distance between this and another color
 */
float CieLab::diffSq(const CieLab &other)
{
    float sum=0.0;
    sum += (L - other.L) * (L - other.L);
    sum += (A - other.A) * (A - other.A);
    sum += (B - other.B) * (B - other.B);
    return sum;
}

/**
 * Computes squared euclidian distance in CieLab space for two colors
 * given as RGB values.
 */
float CieLab::diffSq(unsigned int rgb1, unsigned int rgb2)
{
    CieLab c1(rgb1);
    CieLab c2(rgb2);
    float euclid = c1.diffSq(c2);
    return euclid;
}


/**
 * Computes squared euclidian distance in CieLab space for two colors
 * given as RGB values.
 */
float CieLab::diff(unsigned int rgb0, unsigned int rgb1)
{
    return (float) sqrt(diffSq(rgb0, rgb1));
}



//########################################################################
//#  T U P E L
//########################################################################

/**
 * Helper class for storing the minimum distances to a cluster centroid
 * in background and foreground and the index to the centroids in each
 * signature for a given color.
 */
00294 class Tupel {
public:

    Tupel()
        {
        minBgDist  = 0.0f;
        indexMinBg = 0;
        minFgDist  = 0.0f;
        indexMinFg = 0;
        }
    Tupel(float minBgDistArg, long indexMinBgArg,
          float minFgDistArg, long indexMinFgArg)
        {
        minBgDist  = minBgDistArg;
        indexMinBg = indexMinBgArg;
        minFgDist  = minFgDistArg;
        indexMinFg = indexMinFgArg;
        }
    Tupel(const Tupel &other)
        {
        minBgDist  = other.minBgDist;
        indexMinBg = other.indexMinBg;
        minFgDist  = other.minFgDist;
        indexMinFg = other.indexMinFg;
        }
    Tupel &operator=(const Tupel &other)
        {
        minBgDist  = other.minBgDist;
        indexMinBg = other.indexMinBg;
        minFgDist  = other.minFgDist;
        indexMinFg = other.indexMinFg;
        return *this;
        }
    virtual ~Tupel()
        {}

    float minBgDist;
    long  indexMinBg;
    float minFgDist;
    long  indexMinFg;

 };



//########################################################################
//#  S I O X    I M A G E
//########################################################################

/**
 *  Create an image with the given width and height
 */
00346 SioxImage::SioxImage(unsigned int widthArg, unsigned int heightArg)
{
    init(width, height);
}

/**
 *  Copy constructor
 */
00354 SioxImage::SioxImage(const SioxImage &other)
{
    pixdata = NULL;
    cmdata  = NULL;
    assign(other);
}

/**
 *  Assignment
 */
00364 SioxImage &SioxImage::operator=(const SioxImage &other)
{
    assign(other);
    return *this;
}


/**
 * Clean up after use.
 */
00374 SioxImage::~SioxImage()
{
    if (pixdata) delete[] pixdata;
    if (cmdata)  delete[] cmdata;
}

/**
 * Error logging
 */
00383 void SioxImage::error(char *fmt, ...)
{
    char msgbuf[256];
    va_list args;
    va_start(args, fmt);
    vsnprintf(msgbuf, 255, fmt, args);
    va_end(args) ;
#ifdef HAVE_GLIB
    g_warning("SioxImage error: %s\n", msgbuf);
#else
    fprintf(stderr, "SioxImage error: %s\n", msgbuf);
#endif
}


/**
 * Returns true if the previous operation on this image
 * was successful, else false.
 */
00402 bool SioxImage::isValid()
{
    return valid;
}

/**
 * Sets whether an operation was successful, and whether
 * this image should be considered a valid one.
 * was successful, else false.
 */
00412 void SioxImage::setValid(bool val)
{
    valid = val;
}


/**
 * Set a pixel at the x,y coordinates to the given value.
 * If the coordinates are out of range, do nothing.
 */
00422 void SioxImage::setPixel(unsigned int x,
                         unsigned int y,
                         unsigned int pixval)
{
    if (x >= width || y >= height)
        {
        error("setPixel: out of bounds (%d,%d)/(%d,%d)",
                   x, y, width, height);
        return;
        }
    unsigned long offset = width * y + x;
    pixdata[offset] = pixval; 
}

/**
 * Set a pixel at the x,y coordinates to the given r, g, b values.
 * If the coordinates are out of range, do nothing.
 */
00440 void SioxImage::setPixel(unsigned int x, unsigned int y,
                         unsigned int a, 
                         unsigned int r, 
                         unsigned int g,
                         unsigned int b)
{
    if (x >= width || y >= height)
        {
        error("setPixel: out of bounds (%d,%d)/(%d,%d)",
                   x, y, width, height);
        return;
        }
    unsigned long offset = width * y + x;
    unsigned int pixval = ((a << 24) & 0xff000000) |
                          ((r << 16) & 0x00ff0000) |
                          ((g <<  8) & 0x0000ff00) |
                          ((b      ) & 0x000000ff);
    pixdata[offset] = pixval;
}



/**
 *  Get a pixel at the x,y coordinates given.  If
 *  the coordinates are out of range, return 0;
 */
00466 unsigned int SioxImage::getPixel(unsigned int x, unsigned int y)
{
    if (x >= width || y >= height)
        {
        error("getPixel: out of bounds (%d,%d)/(%d,%d)",
                   x, y, width, height);
        return 0L;
        }
    unsigned long offset = width * y + x;
    return pixdata[offset]; 
}

/**
 *  Return the image data buffer
 */
00481 unsigned int *SioxImage::getImageData()
{
    return pixdata;
}

/**
 * Set a confidence value at the x,y coordinates to the given value.
 * If the coordinates are out of range, do nothing.
 */
00490 void SioxImage::setConfidence(unsigned int x,
                              unsigned int y,
                              float confval)
{
    if (x >= width || y >= height)
        {
        error("setConfidence: out of bounds (%d,%d)/(%d,%d)",
                   x, y, width, height);
        return;
        }
    unsigned long offset = width * y + x;
    cmdata[offset] = confval; 
}

/**
 *  Get a confidence valueat the x,y coordinates given.  If
 *  the coordinates are out of range, return 0;
 */
00508 float SioxImage::getConfidence(unsigned int x, unsigned int y)
{
    if (x >= width || y >= height)
        {
        g_warning("getConfidence: out of bounds (%d,%d)/(%d,%d)",
                   x, y, width, height);
        return 0.0;
        }
    unsigned long offset = width * y + x;
    return cmdata[offset]; 
}

/**
 *  Return the confidence data buffer
 */
00523 float *SioxImage::getConfidenceData()
{
    return cmdata;
}


/**
 * Return the width of this image
 */
00532 int SioxImage::getWidth()
{
    return width;
}

/**
 * Return the height of this image
 */
00540 int SioxImage::getHeight()
{
    return height;
}

/**
 * Initialize values.  Used by constructors
 */
00548 void SioxImage::init(unsigned int widthArg, unsigned int heightArg)
{
    valid     = true;
    width     = widthArg;
    height    = heightArg;
    imageSize = width * height;
    pixdata   = new unsigned int[imageSize];
    cmdata    = new float[imageSize];
    for (unsigned long i=0 ; i<imageSize ; i++)
        {
        pixdata[i] = 0;
        cmdata[i]  = 0.0;
        }
}

/**
 * Assign values to that of another
 */
00566 void SioxImage::assign(const SioxImage &other)
{
    if (pixdata) delete[] pixdata;
    if (cmdata)  delete[] cmdata;
    valid     = other.valid;
    width     = other.width;
    height    = other.height;
    imageSize = width * height;
    pixdata   = new unsigned int[imageSize];
    cmdata    = new float[imageSize];
    for (unsigned long i=0 ; i<imageSize ; i++)
        {
        pixdata[i] = other.pixdata[i];
        cmdata[i]  = other.cmdata[i];
        }
}


/**
 * Write the image to a PPM file
 */
00587 bool SioxImage::writePPM(const std::string fileName)
{

    FILE *f = fopen(fileName.c_str(), "wb");
    if (!f)
        return false;

    fprintf(f, "P6 %d %d 255\n", width, height);

    for (unsigned int y=0 ; y<height; y++)
        {
        for (unsigned int x=0 ; x<width ; x++)
            {
            unsigned int rgb = getPixel(x, y);
            //unsigned int alpha = (rgb>>24) & 0xff;
            unsigned int r = ((rgb>>16) & 0xff);
            unsigned int g = ((rgb>> 8) & 0xff);
            unsigned int b = ((rgb    ) & 0xff);
            fputc((unsigned char) r, f);
            fputc((unsigned char) g, f);
            fputc((unsigned char) b, f);
            }
        }
    fclose(f);
    return true;
}


#ifdef HAVE_GLIB

/**
 * Create an image from a GdkPixbuf
 */
00620 SioxImage::SioxImage(GdkPixbuf *buf)
{
    if (!buf)
        return;

    unsigned int width  = gdk_pixbuf_get_width(buf);
    unsigned int height = gdk_pixbuf_get_height(buf);
    init(width, height); //DO THIS NOW!!


    guchar *pixldata    = gdk_pixbuf_get_pixels(buf);
    int rowstride       = gdk_pixbuf_get_rowstride(buf);
    int n_channels      = gdk_pixbuf_get_n_channels(buf);

    //### Fill in the cells with RGB values
    int row  = 0;
    for (unsigned int y=0 ; y<height ; y++)
        {
        guchar *p = pixldata + row;
        for (unsigned int x=0 ; x<width ; x++)
            {
            int r     = (int)p[0];
            int g     = (int)p[1];
            int b     = (int)p[2];
            int alpha = (int)p[3];

            setPixel(x, y, alpha, r, g, b);
            p += n_channels;
            }
        row += rowstride;
        }

}


/**
 * Create a GdkPixbuf from this image
 */
00658 GdkPixbuf *SioxImage::getGdkPixbuf()
{
    bool has_alpha = true;
    int n_channels = has_alpha ? 4 : 3;

    guchar *pixdata = (guchar *)
          malloc(sizeof(guchar) * width * height * n_channels);
    if (!pixdata)
        return NULL;

    int rowstride  = width * n_channels;

    GdkPixbuf *buf = gdk_pixbuf_new_from_data(pixdata,
                        GDK_COLORSPACE_RGB,
                        has_alpha, 8, width, height,
                        rowstride, NULL, NULL);

    //### Fill in the cells with RGB values
    int row  = 0;
    for (unsigned int y=0 ; y < height ; y++)
        {
        guchar *p = pixdata + row;
        for (unsigned x=0 ; x < width ; x++)
            {
            unsigned int rgb = getPixel(x, y);
            p[0] = (rgb >> 16) & 0xff;//r
            p[1] = (rgb >>  8) & 0xff;//g
            p[2] = (rgb      ) & 0xff;//b
            if ( n_channels > 3 )
                {
                p[3] = (rgb >> 24) & 0xff;//a
                }
            p += n_channels;
            }
        row += rowstride;
        }

    return buf;
}

#endif /* GLIB */




//########################################################################
//#  S I O X
//########################################################################

//##############
//## PUBLIC
//##############

/**
 * Confidence corresponding to a certain foreground region (equals one).
 */
const float Siox::CERTAIN_FOREGROUND_CONFIDENCE=1.0f;

/**
 * Confidence for a region likely being foreground.
 */
const float Siox::FOREGROUND_CONFIDENCE=0.8f;

/** 
 * Confidence for foreground or background type being equally likely.
 */
const float Siox::UNKNOWN_REGION_CONFIDENCE=0.5f;

/**
 * Confidence for a region likely being background.
 */
const float Siox::BACKGROUND_CONFIDENCE=0.1f;

/**
 * Confidence corresponding to a certain background reagion (equals zero).
 */
const float Siox::CERTAIN_BACKGROUND_CONFIDENCE=0.0f;

/**
 *  Construct a Siox engine
 */
Siox::Siox()
{
    sioxObserver = NULL;
    init();
}

/**
 *  Construct a Siox engine
 */
Siox::Siox(SioxObserver *observer)
{
    init();
    sioxObserver = observer;
}


/**
 *
 */
Siox::~Siox()
{
    cleanup();
}


/**
 * Error logging
 */
void Siox::error(char *fmt, ...)
{
    char msgbuf[256];
    va_list args;
    va_start(args, fmt);
    vsnprintf(msgbuf, 255, fmt, args);
    va_end(args) ;
#ifdef HAVE_GLIB
    g_warning("Siox error: %s\n", msgbuf);
#else
    fprintf(stderr, "Siox error: %s\n", msgbuf);
#endif
}

/**
 * Trace logging
 */
void Siox::trace(char *fmt, ...)
{
    char msgbuf[256];
    va_list args;
    va_start(args, fmt);
    vsnprintf(msgbuf, 255, fmt, args);
    va_end(args) ;
#ifdef HAVE_GLIB
    g_message("Siox: %s\n", msgbuf);
#else
    fprintf(stdout, "Siox: %s\n", msgbuf);
#endif
}



/**
 * Progress reporting
 */
bool Siox::progressReport(float percentCompleted)
{
    if (!sioxObserver)
        return true;

    bool ret = sioxObserver->progress(percentCompleted);

    if (!ret)
      {
      trace("User selected abort");
      keepGoing = false;
      }

    return ret;
}




/**
 *  Extract the foreground of the original image, according
 *  to the values in the confidence matrix.
 */
SioxImage Siox::extractForeground(const SioxImage &originalImage,
                                  unsigned int backgroundFillColor)
{
    trace("### Start");

    init();
    keepGoing = true;

    SioxImage workImage = originalImage;

    //# fetch some info from the image
    width      = workImage.getWidth();
    height     = workImage.getHeight();
    pixelCount = width * height;
    image      = workImage.getImageData();
    cm         = workImage.getConfidenceData();
    labelField = new int[pixelCount];

    trace("### Creating signatures");

    //#### create color signatures
    std::vector<CieLab> knownBg;
    std::vector<CieLab> knownFg;
    CieLab *imageClab = new CieLab[pixelCount];
    for (unsigned long i=0 ; i<pixelCount ; i++)
        {
        float conf = cm[i];
        unsigned int pix = image[i];
        CieLab lab(pix);
        imageClab[i] = lab;
        if (conf <= BACKGROUND_CONFIDENCE)
            knownBg.push_back(lab);
        else if (conf >= FOREGROUND_CONFIDENCE)
            knownFg.push_back(lab);
        }

    /*
    std::vector<CieLab> imageClab;
    for (int y = 0 ; y < workImage.getHeight() ; y++)
        for (int x = 0 ; x < workImage.getWidth() ; x++)
            {
            float cm = workImage.getConfidence(x, y);
            unsigned int pix = workImage.getPixel(x, y);
            CieLab lab(pix);
            imageClab.push_back(lab);
            if (cm <= BACKGROUND_CONFIDENCE)
                knownBg.push_back(lab); //note: uses CieLab(rgb)
            else if (cm >= FOREGROUND_CONFIDENCE)
                knownFg.push_back(lab);
            }
    */

    if (!progressReport(10.0))
        {
        error("User aborted");
        workImage.setValid(false);
        delete[] imageClab;
        delete[] labelField;
        return workImage;
        }

    trace("knownBg:%zu knownFg:%zu", knownBg.size(), knownFg.size());


    std::vector<CieLab> bgSignature ;
    if (!colorSignature(knownBg, bgSignature, 3))
        {
        error("Could not create background signature");
        workImage.setValid(false);
        delete[] imageClab;
        delete[] labelField;
        return workImage;
        }

    if (!progressReport(30.0))
        {
        error("User aborted");
        workImage.setValid(false);
        delete[] imageClab;
        delete[] labelField;
        return workImage;
        }


    std::vector<CieLab> fgSignature ;
    if (!colorSignature(knownFg, fgSignature, 3))
        {
        error("Could not create foreground signature");
        workImage.setValid(false);
        delete[] imageClab;
        delete[] labelField;
        return workImage;
        }

    //trace("### bgSignature:%d", bgSignature.size());

    if (bgSignature.size() < 1)
        {
        // segmentation impossible
        error("Signature size is < 1.  Segmentation is impossible");
        workImage.setValid(false);
        delete[] imageClab;
        delete[] labelField;
        return workImage;
        }

    if (!progressReport(30.0))
        {
        error("User aborted");
        workImage.setValid(false);
        delete[] imageClab;
        delete[] labelField;
        return workImage;
        }


    // classify using color signatures,
    // classification cached in hashmap for drb and speedup purposes
    trace("### Analyzing image");

    std::map<unsigned int, Tupel> hs;
    
    unsigned int progressResolution = pixelCount / 10;

    for (unsigned int i=0; i<pixelCount; i++)
        {
        if (i % progressResolution == 0)
            {
            float progress = 
                30.0 + 60.0 * (float)i / (float)pixelCount;
            //trace("### progress:%f", progress);
            if (!progressReport(progress))
                {
                error("User aborted");
                delete[] imageClab;
                delete[] labelField;
                workImage.setValid(false);
                return workImage;
                }
            }

        if (cm[i] >= FOREGROUND_CONFIDENCE)
            {
            cm[i] = CERTAIN_FOREGROUND_CONFIDENCE;
            }
        else if (cm[i] <= BACKGROUND_CONFIDENCE)
            {
            cm[i] = CERTAIN_BACKGROUND_CONFIDENCE;
            }
        else // somewhere in between
            {
            bool isBackground = true;
            std::map<unsigned int, Tupel>::iterator iter = hs.find(i);
            if (iter != hs.end()) //found
                {
                Tupel tupel  = iter->second;
                isBackground = tupel.minBgDist <= tupel.minFgDist;
                }
            else
                {
                CieLab lab   = imageClab[i];
                float minBg  = lab.diffSq(bgSignature[0]);
                int minIndex = 0;
                for (unsigned int j=1; j<bgSignature.size() ; j++)
                    {
                    float d = lab.diffSq(bgSignature[j]);
                    if (d<minBg)
                        {
                        minBg    = d;
                        minIndex = j;
                        }
                    }
                Tupel tupel(0.0f, 0,  0.0f, 0);
                tupel.minBgDist  = minBg;
                tupel.indexMinBg = minIndex;
                float minFg      = 1.0e6f;
                minIndex         = -1;
                for (unsigned int j = 0 ; j < fgSignature.size() ; j++)
                    {
                    float d = lab.diffSq(fgSignature[j]);
                    if (d < minFg)
                        {
                        minFg    = d;
                        minIndex = j;
                        }
                    }
                tupel.minFgDist  = minFg;
                tupel.indexMinFg = minIndex;
                if (fgSignature.size() == 0)
                    {
                    isBackground = (minBg <= clusterSize);
                    // remove next line to force behaviour of old algorithm
                    //error("foreground signature does not exist");
                    //delete[] labelField;
                    //workImage.setValid(false);
                    //return workImage;
                    }
                else
                    {
                    isBackground = minBg < minFg;
                    }
                hs[image[i]] = tupel;
                }

            if (isBackground)
                cm[i] = CERTAIN_BACKGROUND_CONFIDENCE;
            else
                cm[i] = CERTAIN_FOREGROUND_CONFIDENCE;
            }
        }


    delete[] imageClab;

    trace("### postProcessing");


    //#### postprocessing
    smooth(cm, width, height, 0.333f, 0.333f, 0.333f); // average
    normalizeMatrix(cm, pixelCount);
    erode(cm, width, height);
    keepOnlyLargeComponents(UNKNOWN_REGION_CONFIDENCE, 1.0/*sizeFactorToKeep*/);

    //for (int i=0; i < 2/*smoothness*/; i++)
    //    smooth(cm, width, height, 0.333f, 0.333f, 0.333f); // average

    normalizeMatrix(cm, pixelCount);

    for (unsigned int i=0; i < pixelCount; i++)
        {
        if (cm[i] >= UNKNOWN_REGION_CONFIDENCE)
            cm[i] = CERTAIN_FOREGROUND_CONFIDENCE;
        else
            cm[i] = CERTAIN_BACKGROUND_CONFIDENCE;
        }

    keepOnlyLargeComponents(UNKNOWN_REGION_CONFIDENCE, 1.5/*sizeFactorToKeep*/);
    fillColorRegions();
    dilate(cm, width, height);

    if (!progressReport(100.0))
        {
        error("User aborted");
        delete[] labelField;
        workImage.setValid(false);
        return workImage;
        }


    //#### We are done.  Now clear everything but the background
    for (unsigned long i = 0; i<pixelCount ; i++)
        {
        float conf = cm[i];
        if (conf < FOREGROUND_CONFIDENCE)
            image[i] = backgroundFillColor;
        }

    delete[] labelField;

    trace("### Done");
    keepGoing = false;
    return workImage;
}



//##############
//## PRIVATE
//##############

/**
 *  Initialize the Siox engine to its 'pristine' state.
 *  Performed at the beginning of extractForeground().
 */
void Siox::init()
{
    limits[0] = 0.64f;
    limits[1] = 1.28f;
    limits[2] = 2.56f;

    float negLimits[3];
    negLimits[0] = -limits[0];
    negLimits[1] = -limits[1];
    negLimits[2] = -limits[2];

    clusterSize = sqrEuclidianDist(limits, 3, negLimits);
}


/**
 *  Clean up any debris from processing.
 */
void Siox::cleanup()
{
}




/**
 *  Stage 1 of the color signature work.  'dims' will be either
 *  2 for grays, or 3 for colors
 */
void Siox::colorSignatureStage1(CieLab *points,
                                unsigned int leftBase,
                                unsigned int rightBase,
                                unsigned int recursionDepth,
                                unsigned int *clusterCount,
                                const unsigned int dims)
{

    unsigned int currentDim = recursionDepth % dims;
    CieLab point = points[leftBase];
    float min = point(currentDim);
    float max = min;

    for (unsigned int i = leftBase + 1; i < rightBase ; i++)
        {
        point = points[i];
        float curval = point(currentDim);
        if (curval < min) min = curval;
        if (curval > max) max = curval;
        }

    //Do the Rubner-rule split (sounds like a dance)
    if (max - min > limits[currentDim])
        {
        float pivotPoint = (min + max) / 2.0; //average
        unsigned int left  = leftBase;
        unsigned int right = rightBase - 1;

        //# partition points according to the dimension
        while (true)
            {
            while ( true )
                {
                point = points[left];
                if (point(currentDim) > pivotPoint)
                    break;
                left++;
                }
            while ( true )
                {
                point = points[right];
                if (point(currentDim) <= pivotPoint)
                    break;
                right--;
                }

            if (left > right)
                break;

            point = points[left];
            points[left] = points[right];
            points[right] = point;

            left++;
            right--;
            }

        //# Recurse and create sub-trees
        colorSignatureStage1(points, leftBase, left,
                 recursionDepth + 1, clusterCount, dims);
        colorSignatureStage1(points, left, rightBase,
                 recursionDepth + 1, clusterCount, dims);
        }
    else
        {
        //create a leaf
        CieLab newpoint;

        newpoint.C = rightBase - leftBase;

        for (; leftBase < rightBase ; leftBase++)
            {
            newpoint.add(points[leftBase]);
            }

        //printf("clusters:%d\n", *clusters);

        if (newpoint.C != 0)
            newpoint.mul(1.0 / (float)newpoint.C);
        points[*clusterCount] = newpoint;
        (*clusterCount)++;
        }
}



/**
 *  Stage 2 of the color signature work
 */
void Siox::colorSignatureStage2(CieLab         *points,
                                unsigned int leftBase,
                                unsigned int rightBase,
                                unsigned int recursionDepth,
                                unsigned int *clusterCount,
                                const float  threshold,
                                const unsigned int dims)
{

  
    unsigned int currentDim = recursionDepth % dims;
    CieLab point = points[leftBase];
    float min = point(currentDim);
    float max = min;

    for (unsigned int i = leftBase+ 1; i < rightBase; i++)
        {
        point = points[i];
        float curval = point(currentDim);
        if (curval < min) min = curval;
        if (curval > max) max = curval;
        }

    //Do the Rubner-rule split (sounds like a dance)
    if (max - min > limits[currentDim])
        {
        float pivotPoint = (min + max) / 2.0; //average
        unsigned int left  = leftBase;
        unsigned int right = rightBase - 1;

        //# partition points according to the dimension
        while (true)
            {
            while ( true )
                {
                point = points[left];
                if (point(currentDim) > pivotPoint)
                    break;
                left++;
                }
            while ( true )
                {
                point = points[right];
                if (point(currentDim) <= pivotPoint)
                    break;
                right--;
                }

            if (left > right)
                break;

            point = points[left];
            points[left] = points[right];
            points[right] = point;

            left++;
            right--;
            }

        //# Recurse and create sub-trees
        colorSignatureStage2(points, leftBase, left,
                 recursionDepth + 1, clusterCount, threshold, dims);
        colorSignatureStage2(points, left, rightBase,
                 recursionDepth + 1, clusterCount, threshold, dims);
        }
    else
        {
        //### Create a leaf
        unsigned int sum = 0;
        for (unsigned int i = leftBase; i < rightBase; i++)
            sum += points[i].C;

        if ((float)sum >= threshold)
            {
            float scale = (float)(rightBase - leftBase);
            CieLab newpoint;

            for (; leftBase < rightBase; leftBase++)
                newpoint.add(points[leftBase]);

            if (scale != 0.0)
                newpoint.mul(1.0 / scale);
            points[*clusterCount] = newpoint;
            (*clusterCount)++;
            }
      }
}



/**
 *  Main color signature method
 */
bool Siox::colorSignature(const std::vector<CieLab> &inputVec,
                          std::vector<CieLab> &result,
                          const unsigned int dims)
{

    unsigned int length = inputVec.size();

    if (length < 1) // no error. just don't do anything
        return true;

    CieLab *input = (CieLab *) malloc(length * sizeof(CieLab));

    if (!input)
        {
        error("Could not allocate buffer for signature");
        return false;
        }        
    for (unsigned int i=0 ; i < length ; i++)
        input[i] = inputVec[i];

    unsigned int stage1length = 0;
    colorSignatureStage1(input, 0, length, 0,
                   &stage1length, dims);

    unsigned int stage2length = 0;
    colorSignatureStage2(input, 0, stage1length, 0,
                  &stage2length, length * 0.001, dims);

    result.clear();
    for (unsigned int i=0 ; i < stage2length ; i++)
        result.push_back(input[i]);

    free(input);

    return true;
}



/**
 *
 */
void Siox::keepOnlyLargeComponents(float threshold,
                                   double sizeFactorToKeep)
{
    for (unsigned long idx = 0 ; idx<pixelCount ; idx++)
        labelField[idx] = -1;

    int curlabel = 0;
    int maxregion= 0;
    int maxblob  = 0;

    // slow but easy to understand:
    std::vector<int> labelSizes;
    for (unsigned long i=0 ; i<pixelCount ; i++)
        {
        int regionCount = 0;
        if (labelField[i] == -1 && cm[i] >= threshold)
            {
            regionCount = depthFirstSearch(i, threshold, curlabel++);
            labelSizes.push_back(regionCount);
            }

        if (regionCount>maxregion)
            {
            maxregion = regionCount;
            maxblob   = curlabel-1;
            }
        }

    for (unsigned int i=0 ; i<pixelCount ; i++)
        {
        if (labelField[i] != -1)
            {
            // remove if the component is to small
            if (labelSizes[labelField[i]] * sizeFactorToKeep < maxregion)
                cm[i] = CERTAIN_BACKGROUND_CONFIDENCE;

            // add maxblob always to foreground
            if (labelField[i] == maxblob)
                cm[i] = CERTAIN_FOREGROUND_CONFIDENCE;
            }
        }

}



int Siox::depthFirstSearch(int startPos,
              float threshold, int curLabel)
{
    // stores positions of labeled pixels, where the neighbours
    // should still be checked for processing:

    //trace("startPos:%d threshold:%f curLabel:%d",
    //     startPos, threshold, curLabel);

    std::vector<int> pixelsToVisit;
    int componentSize = 0;

    if (labelField[startPos]==-1 && cm[startPos]>=threshold)
        {
        labelField[startPos] = curLabel;
        componentSize++;
        pixelsToVisit.push_back(startPos);
        }


    while (pixelsToVisit.size() > 0)
        {
        int pos = pixelsToVisit[pixelsToVisit.size() - 1];
        pixelsToVisit.erase(pixelsToVisit.end() - 1);
        unsigned int x = pos % width;
        unsigned int y = pos / width;

        // check all four neighbours
        int left = pos - 1;
        if (((int)x)-1>=0 && labelField[left]==-1 && cm[left]>=threshold)
            {
            labelField[left]=curLabel;
            componentSize++;
            pixelsToVisit.push_back(left);
            }

        int right = pos + 1;
        if (x+1 < width && labelField[right]==-1 && cm[right]>=threshold)
            {
            labelField[right]=curLabel;
            componentSize++;
            pixelsToVisit.push_back(right);
            }

        int top = pos - width;
        if (((int)y)-1>=0 && labelField[top]==-1 && cm[top]>=threshold)
            {
            labelField[top]=curLabel;
            componentSize++;
            pixelsToVisit.push_back(top);
            }

        int bottom = pos + width;
        if (y+1 < height && labelField[bottom]==-1
                         && cm[bottom]>=threshold)
            {
            labelField[bottom]=curLabel;
            componentSize++;
            pixelsToVisit.push_back(bottom);
            }

        }
    return componentSize;
}



/**
 *
 */
void Siox::fillColorRegions()
{
    for (unsigned long idx = 0 ; idx<pixelCount ; idx++)
        labelField[idx] = -1;

    //int maxRegion=0; // unused now
    std::vector<int> pixelsToVisit;
    for (unsigned long i=0; i<pixelCount; i++)
        { // for all pixels
        if (labelField[i]!=-1 || cm[i]<UNKNOWN_REGION_CONFIDENCE)
            {
            continue; // already visited or bg
            }

        unsigned int  origColor = image[i];
        unsigned long curLabel  = i+1;
        labelField[i]           = curLabel;
        cm[i]                   = CERTAIN_FOREGROUND_CONFIDENCE;

        // int componentSize = 1;
        pixelsToVisit.push_back(i);
        // depth first search to fill region
        while (pixelsToVisit.size() > 0)
            {
            int pos = pixelsToVisit[pixelsToVisit.size() - 1];
            pixelsToVisit.erase(pixelsToVisit.end() - 1);
            unsigned int x=pos % width;
            unsigned int y=pos / width;
            // check all four neighbours
            int left = pos-1;
            if (((int)x)-1 >= 0 && labelField[left] == -1
                        && CieLab::diff(image[left], origColor)<1.0)
                {
                labelField[left]=curLabel;
                cm[left]=CERTAIN_FOREGROUND_CONFIDENCE;
                // ++componentSize;
                pixelsToVisit.push_back(left);
                }
            int right = pos+1;
            if (x+1 < width && labelField[right]==-1
                        && CieLab::diff(image[right], origColor)<1.0)
                {
                labelField[right]=curLabel;
                cm[right]=CERTAIN_FOREGROUND_CONFIDENCE;
                // ++componentSize;
                pixelsToVisit.push_back(right);
                }
            int top = pos - width;
            if (((int)y)-1>=0 && labelField[top]==-1
                        && CieLab::diff(image[top], origColor)<1.0)
                {
                labelField[top]=curLabel;
                cm[top]=CERTAIN_FOREGROUND_CONFIDENCE;
                // ++componentSize;
                pixelsToVisit.push_back(top);
                }
            int bottom = pos + width;
            if (y+1 < height && labelField[bottom]==-1
                        && CieLab::diff(image[bottom], origColor)<1.0)
                {
                labelField[bottom]=curLabel;
                cm[bottom]=CERTAIN_FOREGROUND_CONFIDENCE;
                // ++componentSize;
                pixelsToVisit.push_back(bottom);
                }
            }
        //if (componentSize>maxRegion) {
        //    maxRegion=componentSize;
        //}
        }
}




/**
 * Applies the morphological dilate operator.
 *
 * Can be used to close small holes in the given confidence matrix.
 */
void Siox::dilate(float *cm, int xres, int yres)
{

    for (int y=0; y<yres; y++)
        {
        for (int x=0; x<xres-1; x++)
             {
             int idx=(y*xres)+x;
             if (cm[idx+1]>cm[idx])
                 cm[idx]=cm[idx+1];
             }
        }

    for (int y=0; y<yres; y++)
        {
        for (int x=xres-1; x>=1; x--)
            {
            int idx=(y*xres)+x;
            if (cm[idx-1]>cm[idx])
                cm[idx]=cm[idx-1];
            }
        }

    for (int y=0; y<yres-1; y++)
        {
        for (int x=0; x<xres; x++)
            {
            int idx=(y*xres)+x;
            if (cm[((y+1)*xres)+x] > cm[idx])
                cm[idx]=cm[((y+1)*xres)+x];
            }
        }

    for (int y=yres-1; y>=1; y--)
        {
        for (int x=0; x<xres; x++)
            {
            int idx=(y*xres)+x;
            if (cm[((y-1)*xres)+x] > cm[idx])
                cm[idx]=cm[((y-1)*xres)+x];
            }
        }
}

/**
 * Applies the morphological erode operator.
 */
void Siox::erode(float *cm, int xres, int yres)
{
    for (int y=0; y<yres; y++)
        {
        for (int x=0; x<xres-1; x++)
            {
            int idx=(y*xres)+x;
            if (cm[idx+1] < cm[idx])
                cm[idx]=cm[idx+1];
            }
        }
    for (int y=0; y<yres; y++)
        {
        for (int x=xres-1; x>=1; x--)
            {
            int idx=(y*xres)+x;
            if (cm[idx-1] < cm[idx])
                cm[idx]=cm[idx-1];
            }
        }
    for (int y=0; y<yres-1; y++)
        {
        for (int x=0; x<xres; x++)
            {
            int idx=(y*xres)+x;
            if (cm[((y+1)*xres)+x] < cm[idx])
                cm[idx]=cm[((y+1)*xres)+x];
            }
        }
    for (int y=yres-1; y>=1; y--)
        {
        for (int x=0; x<xres; x++)
            {
            int idx=(y*xres)+x;
            if (cm[((y-1)*xres)+x] < cm[idx])
                cm[idx]=cm[((y-1)*xres)+x];
            }
        }
}



/**
 * Normalizes the matrix to values to [0..1].
 */
void Siox::normalizeMatrix(float *cm, int cmSize)
{
    float max= -1000000.0f;
    for (int i=0; i<cmSize; i++)
        if (cm[i] > max) max=cm[i];
        
    //good to use STL, but max() is not iterative
    //float max = *std::max(cm, cm + cmSize);

    if (max<=0.0 || max==1.0)
        return;

    float alpha=1.00f/max;
    premultiplyMatrix(alpha, cm, cmSize);
}

/**
 * Multiplies matrix with the given scalar.
 */
void Siox::premultiplyMatrix(float alpha, float *cm, int cmSize)
{
    for (int i=0; i<cmSize; i++)
        cm[i]=alpha*cm[i];
}

/**
 * Blurs confidence matrix with a given symmetrically weighted kernel.
 *
 * In the standard case confidence matrix entries are between 0...1 and
 * the weight factors sum up to 1.
 */
void Siox::smooth(float *cm, int xres, int yres,
                  float f1, float f2, float f3)
{
    for (int y=0; y<yres; y++)
        {
        for (int x=0; x<xres-2; x++)
            {
            int idx=(y*xres)+x;
            cm[idx]=f1*cm[idx]+f2*cm[idx+1]+f3*cm[idx+2];
            }
        }
    for (int y=0; y<yres; y++)
        {
        for (int x=xres-1; x>=2; x--)
            {
            int idx=(y*xres)+x;
            cm[idx]=f3*cm[idx-2]+f2*cm[idx-1]+f1*cm[idx];
            }
        }
    for (int y=0; y<yres-2; y++)
        {
        for (int x=0; x<xres; x++)
            {
            int idx=(y*xres)+x;
            cm[idx]=f1*cm[idx]+f2*cm[((y+1)*xres)+x]+f3*cm[((y+2)*xres)+x];
            }
        }
    for (int y=yres-1; y>=2; y--)
        {
        for (int x=0; x<xres; x++)
            {
            int idx=(y*xres)+x;
            cm[idx]=f3*cm[((y-2)*xres)+x]+f2*cm[((y-1)*xres)+x]+f1*cm[idx];
            }
        }
}

/**
 * Squared Euclidian distance of p and q.
 */
float Siox::sqrEuclidianDist(float *p, int pSize, float *q)
{
    float sum=0.0;
    for (int i=0; i<pSize; i++)
        {
        float v = p[i] - q[i];
        sum += v*v;
        }
    return sum;
}






} // namespace siox
} // namespace org

//########################################################################
//#  E N D    O F    F I L E
//########################################################################