cvlinefit.cpp.svn-base

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#include "_cv.h"
#include "_cvutils.h"

#include <math.h>

#define _FP double

#if _MSC_VER >= 1200
#pragma warning (disable:4701)
#endif

CvStatus
icvFitLine2D_wods( CvPoint2D32f * points, int _count, float *weights, float *line )
{
    _FP x = 0, y = 0, x2 = 0, y2 = 0, xy = 0, w = 0;
    _FP dx2, dy2, dxy;
    int i;
    int count = _count;
    float t;

    /* Calculating the average of x and y... */

    if( weights == 0 )
    {
        for( i = 0; i < count; i += 1 )
        {
            x += points[i].x;
            y += points[i].y;
            x2 += points[i].x * points[i].x;
            y2 += points[i].y * points[i].y;
            xy += points[i].x * points[i].y;
        }
        w = (float) count;
    }
    else
    {
        for( i = 0; i < count; i += 1 )
        {
            x += weights[i] * points[i].x;
            y += weights[i] * points[i].y;
            x2 += weights[i] * points[i].x * points[i].x;
            y2 += weights[i] * points[i].y * points[i].y;
            xy += weights[i] * points[i].x * points[i].y;
            w += weights[i];
        }
    }

    x /= w;
    y /= w;
    x2 /= w;
    y2 /= w;
    xy /= w;

    dx2 = x2 - x * x;
    dy2 = y2 - y * y;
    dxy = xy - x * y;

    t = (float) atan2( 2 * dxy, dx2 - dy2 ) / 2;
    line[0] = (float) cos( t );
    line[1] = (float) sin( t );

    line[2] = (float) x;
    line[3] = (float) y;

    return CV_NO_ERR;
}

CvStatus
icvFitLine3D_wods( CvPoint3D32f * points, int count, float *weights, float *line )
{
    int i;
    CvStatus ret;
    float w0 = 0;
    float x0 = 0, y0 = 0, z0 = 0;
    float x2 = 0, y2 = 0, z2 = 0, xy = 0, yz = 0, xz = 0;
    float dx2, dy2, dz2, dxy, dxz, dyz;
    float *v;
    float n;
    float det[9], evc[9], evl[3];

    memset( evl, 0, 3*sizeof(evl[0]));
    memset( evc, 0, 9*sizeof(evl[0]));

    if( weights )
    {
        for( i = 0; i < count; i++ )
        {
            float x = points[i].x;
            float y = points[i].y;
            float z = points[i].z;
            float w = weights[i];


            x2 += x * x * w;
            xy += x * y * w;
            xz += x * z * w;
            y2 += y * y * w;
            yz += y * z * w;
            z2 += z * z * w;
            x0 += x * w;
            y0 += y * w;
            z0 += z * w;
            w0 += w;
        }
    }
    else
    {
        for( i = 0; i < count; i++ )
        {
            float x = points[i].x;
            float y = points[i].y;
            float z = points[i].z;

            x2 += x * x;
            xy += x * y;
            xz += x * z;
            y2 += y * y;
            yz += y * z;
            z2 += z * z;
            x0 += x;
            y0 += y;
            z0 += z;
        }
        w0 = (float) count;
    }

    x2 /= w0;
    xy /= w0;
    xz /= w0;
    y2 /= w0;
    yz /= w0;
    z2 /= w0;

    x0 /= w0;
    y0 /= w0;
    z0 /= w0;

    dx2 = x2 - x0 * x0;
    dxy = xy - x0 * y0;
    dxz = xz - x0 * z0;
    dy2 = y2 - y0 * y0;
    dyz = yz - y0 * z0;
    dz2 = z2 - z0 * z0;

    det[0] = dz2 + dy2;
    det[1] = -dxy;
    det[2] = -dxz;
    det[3] = det[1];
    det[4] = dx2 + dz2;
    det[5] = -dyz;
    det[6] = det[2];
    det[7] = det[5];
    det[8] = dy2 + dx2;

    /* Searching for a eigenvector of det corresponding to the minimal eigenvalue */
    ret = icvJacobiEigens_32f( det, evc, evl, 3, 0 );
    if( ret != CV_NO_ERR )
    {
        return ret;
    }

    i = evl[0] < evl[1] ? (evl[0] < evl[2] ? 0 : 2) : (evl[1] < evl[2] ? 1 : 2);
    v = &evc[i * 3];
    n = (float) sqrt( (double)v[0] * v[0] + (double)v[1] * v[1] + (double)v[2] * v[2] );
    line[0] = v[0] / n;
    line[1] = v[1] / n;
    line[2] = v[2] / n;
    line[3] = x0;
    line[4] = y0;
    line[5] = z0;

    return CV_NO_ERR;
}

void
icvCalcDist2D( CvPoint2D32f * points, int count, float *_line, float *dist )
{
    int j;
    float px = _line[2], py = _line[3];
    float nx = _line[1], ny = -_line[0];

    for( j = 0; j < count; j++ )
    {
        float x, y;

        x = points[j].x - px;
        y = points[j].y - py;

        dist[j] = (float) fabs( nx * x + ny * y );
    }
}

void
icvCalcDist3D( CvPoint3D32f * points, int count, float *_line, float *dist )
{
    int j;
    float px = _line[3], py = _line[4], pz = _line[5];
    float vx = _line[0], vy = _line[1], vz = _line[2];

    for( j = 0; j < count; j++ )
    {
        float x, y, z;
        double p1, p2, p3;

        x = points[j].x - px;
        y = points[j].y - py;
        z = points[j].z - pz;

        p1 = vy * z - vz * y;
        p2 = vz * x - vx * z;
        p3 = vx * y - vy * x;

        dist[j] = (float) sqrt( p1*p1 + p2*p2 + p3*p3 );
    }
}

void
icvWeightL1( float *d, int count, float *w )
{
    int i;

    for( i = 0; i < count; i++ )
    {
        w[i] = 1 / (float) fabs( (double) d[i] );
    }
}

void
icvWeightL12( float *d, int count, float *w )
{
    int i;

    for( i = 0; i < count; i++ )
    {
        w[i] = 1.0f / (float) sqrt( 1 + (double) (d[i] * d[i] * 0.5) );
    }
}


void
icvWeightHuber( float *d, int count, float *w, float _c )
{
    int i;
    const float c = _c <= 0 ? 1.345f : _c;

    for( i = 0; i < count; i++ )
    {
        if( d[i] < c )
            w[i] = 1.0f;
        else
            w[i] = c/d[i];
    }
}


void
icvWeightFair( float *d, int count, float *w, float _c )
{
    int i;
    const float c = _c == 0 ? 1 / 1.3998f : 1 / _c;

    for( i = 0; i < count; i++ )
    {
        w[i] = 1 / (1 + d[i] * c);
    }
}

void
icvWeightWelsch( float *d, int count, float *w, float _c )
{
    int i;
    const float c = _c == 0 ? 1 / 2.9846f : 1 / _c;

    for( i = 0; i < count; i++ )
    {
        w[i] = (float) exp( -d[i] * d[i] * c * c );
    }
}


/* Takes an array of 2D points, type of distance (including user-defined 
distance specified by callbacks, fills the array of four floats with line
parameters A, B, C, D, where (A, B) is the normalized direction vector,
(C, D) is the point that belongs to the line. */

static CvStatus  icvFitLine2D( CvPoint2D32f * points, int count, CvDisType dist,
                               float _param, float reps, float aeps, float *line )
{
    void (*calc_weights) (float *, int, float *) = 0;
    void (*calc_weights_param) (float *, int, float *, float) = 0;
    float *w;                   /* weights */
    float *r;                   /* square distances */
    int i;
    float _line[6], _lineprev[6];
    int first = 1;
    float rdelta = reps != 0 ? reps : 1.0f;
    float adelta = aeps != 0 ? aeps : 0.01f;
    CvStatus ret;

    switch (dist)
    {
    case CV_DIST_L2:
        return icvFitLine2D_wods( points, count, 0, line );