static int hu_moments_test( void )
{
const double success_error_level = 1e-7;
CvSize size = { 512, 512 };
int i;
IplImage* img = atsCreateImage( size.width, size.height, 8, 1, 0 );
CvMoments moments;
CvHuMoments a, b;
AtsRandState rng_state;
int seed = atsGetSeed();
double nu20, nu02, nu11, nu30, nu21, nu12, nu03;
double err = 0;
char buffer[100];
atsRandInit( &rng_state, 0, 255, seed );
atsbRand8u( &rng_state, (uchar*)(img->imageData), size.width * size.height );
cvMoments( img, &moments, 0 );
atsReleaseImage( img );
nu20 = cvGetNormalizedCentralMoment( &moments, 2, 0 );
nu11 = cvGetNormalizedCentralMoment( &moments, 1, 1 );
nu02 = cvGetNormalizedCentralMoment( &moments, 0, 2 );
nu30 = cvGetNormalizedCentralMoment( &moments, 3, 0 );
nu21 = cvGetNormalizedCentralMoment( &moments, 2, 1 );
nu12 = cvGetNormalizedCentralMoment( &moments, 1, 2 );
nu03 = cvGetNormalizedCentralMoment( &moments, 0, 3 );
cvGetHuMoments( &moments, &a );
b.hu1 = nu20 + nu02;
b.hu2 = sqr(nu20 - nu02) + 4*sqr(nu11);
b.hu3 = sqr(nu30 - 3*nu12) + sqr(3*nu21 - nu03);
b.hu4 = sqr(nu30 + nu12) + sqr(nu21 + nu03);
b.hu5 = (nu30 - 3*nu12)*(nu30 + nu12)*(sqr(nu30 + nu12) - 3*sqr(nu21 + nu03)) +
(3*nu21 - nu03)*(nu21 + nu03)*(3*sqr(nu30 + nu12) - sqr(nu21 + nu03));
b.hu6 = (nu20 - nu02)*(sqr(nu30 + nu12) - sqr(nu21 + nu03)) +
4*nu11*(nu30 + nu12)*(nu21 + nu03);
b.hu7 = (3*nu21 - nu03)*(nu30 + nu12)*(sqr(nu30 + nu12) - 3*sqr(nu21 + nu03)) +
(3*nu12 - nu30)*(nu21 + nu03)*(3*sqr(nu30 + nu12) - sqr(nu21 + nu03));
for( i = 0; i < 7; i++ )
{
double t = rel_err( ((double*)&b)[i], ((double*)&a)[i] );
if( t > err ) err = t;
}
sprintf( buffer, "Accuracy: %.4e", err );
return trsResult( err > success_error_level ? TRS_FAIL : TRS_OK, buffer );
}
/*
* call-seq:
* normalized_central -> float
*
* Retrieves normalized central moment.
*
* ηx_order,y_order= μx_order,y_order/M00((y_order+x_order)/2+1)
*/
VALUE
rb_normalized_central(VALUE self, VALUE x_order, VALUE y_order)
{
return rb_float_new(cvGetNormalizedCentralMoment(CVMOMENTS(self), NUM2INT(x_order), NUM2INT(y_order)));
}
double cveGetNormalizedCentralMoment(CvMoments* moments, int xOrder, int yOrder)
{
return cvGetNormalizedCentralMoment(moments, xOrder, yOrder);
}
