www.pudn.com > OpenCV-Intel.zip > cvcornersubpix.cpp
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#include "_cv.h"
CV_IMPL void
cvFindCornerSubPix( const void* srcarr, CvPoint2D32f* corners,
int count, CvSize win, CvSize zeroZone,
CvTermCriteria criteria )
{
float* buffer = 0;
CV_FUNCNAME( "cvFindCornerSubPix" );
__BEGIN__;
const int MAX_ITERS = 100;
const float drv_x[] = { -1.f, 0.f, 1.f };
const float drv_y[] = { 0.f, 0.5f, 0.f };
float *maskX;
float *maskY;
float *mask;
float *src_buffer;
float *gx_buffer;
float *gy_buffer;
int win_w = win.width * 2 + 1, win_h = win.height * 2 + 1;
int win_rect_size = (win_w + 4) * (win_h + 4);
double coeff;
CvSize size, src_buf_size;
int i, j, k, pt_i;
int max_iters, buffer_size;
double eps;
CvMat stub, *src = (CvMat*)srcarr;
CV_CALL( src = cvGetMat( srcarr, &stub ));
if( CV_MAT_TYPE( src->type ) != CV_8UC1 )
CV_ERROR( CV_StsBadMask, "" );
if( !corners )
CV_ERROR( CV_StsNullPtr, "" );
if( count <= 0 )
CV_ERROR( CV_StsBadSize, "" );
if( win.width <= 0 || win.height <= 0 )
CV_ERROR( CV_StsBadSize, "" );
size = cvGetMatSize( src );
if( size.width < win_w + 4 || size.height < win_h + 4 )
CV_ERROR( CV_StsBadSize, "" );
/* initialize variables, controlling loop termination */
switch( criteria.type )
{
case CV_TERMCRIT_ITER:
eps = 0.f;
max_iters = criteria.max_iter;
break;
case CV_TERMCRIT_EPS:
eps = criteria.epsilon;
max_iters = MAX_ITERS;
break;
case CV_TERMCRIT_ITER | CV_TERMCRIT_EPS:
eps = criteria.epsilon;
max_iters = criteria.max_iter;
break;
default:
assert( 0 );
CV_ERROR( CV_StsBadFlag, "" );
}
eps = MAX( eps, 0 );
eps *= eps; /* use square of error in comparsion operations. */
max_iters = MAX( max_iters, 1 );
max_iters = MIN( max_iters, MAX_ITERS );
/* setup buffer */
buffer_size = (win_rect_size * 5 + win_w + win_h + 32) * sizeof(float);
buffer = (float*)cvAlloc( buffer_size );
/* assign pointers */
maskX = buffer;
maskY = maskX + win_w + 4;
mask = maskY + win_h + 4;
src_buffer = mask + win_w * win_h;
gx_buffer = src_buffer + win_rect_size;
gy_buffer = gx_buffer + win_rect_size;
coeff = 1. / (win.width * win.width);
/* calculate mask */
for( i = -win.width, k = 0; i <= win.width; i++, k++ )
{
maskX[k] = (float)exp( -i * i * coeff );
}
if( win.width == win.height )
{
maskY = maskX;
}
else
{
coeff = 1. / (win.height * win.height);
for( i = -win.height, k = 0; i <= win.height; i++, k++ )
{
maskY[k] = (float) exp( -i * i * coeff );
}
}
for( i = 0; i < win_h; i++ )
{
for( j = 0; j < win_w; j++ )
{
mask[i * win_w + j] = maskX[j] * maskY[i];
}
}
/* make zero_zone */
if( zeroZone.width >= 0 && zeroZone.height >= 0 &&
zeroZone.width * 2 + 1 < win_w && zeroZone.height * 2 + 1 < win_h )
{
for( i = win.height - zeroZone.height; i <= win.height + zeroZone.height; i++ )
{
for( j = win.width - zeroZone.width; j <= win.width + zeroZone.width; j++ )
{
mask[i * win_w + j] = 0;
}
}
}
/* set sizes of image rectangles, used in convolutions */
src_buf_size.width = win_w + 2;
src_buf_size.height = win_h + 2;
/* do optimization loop for all the points */
for( pt_i = 0; pt_i < count; pt_i++ )
{
CvPoint2D32f cT = corners[pt_i], cI = cT;
int iter = 0;
double err;
do
{
CvPoint2D32f cI2;
double a, b, c, bb1, bb2;
IPPI_CALL( icvGetRectSubPix_8u32f_C1R( (uchar*)src->data.ptr, src->step, size,
src_buffer, (win_w + 2) * sizeof( src_buffer[0] ),
cvSize( win_w + 2, win_h + 2 ), cI ));
/* calc derivatives */
icvSepConvSmall3_32f( src_buffer, src_buf_size.width * sizeof(src_buffer[0]),
gx_buffer, win_w * sizeof(gx_buffer[0]),
src_buf_size, drv_x, drv_y, buffer );
icvSepConvSmall3_32f( src_buffer, src_buf_size.width * sizeof(src_buffer[0]),
gy_buffer, win_w * sizeof(gy_buffer[0]),
src_buf_size, drv_y, drv_x, buffer );
a = b = c = bb1 = bb2 = 0;
/* process gradient */
for( i = 0, k = 0; i < win_h; i++ )
{
double py = i - win.height;
for( j = 0; j < win_w; j++, k++ )
{
double m = mask[k];
double tgx = gx_buffer[k];
double tgy = gy_buffer[k];
double gxx = tgx * tgx * m;
double gxy = tgx * tgy * m;
double gyy = tgy * tgy * m;
double px = j - win.width;
a += gxx;
b += gxy;
c += gyy;
bb1 += gxx * px + gxy * py;
bb2 += gxy * px + gyy * py;
}
}
{
double A[4];
double InvA[4];
CvMat matA, matInvA;
A[0] = a;
A[1] = A[2] = b;
A[3] = c;
cvInitMatHeader( &matA, 2, 2, CV_64F, A );
cvInitMatHeader( &matInvA, 2, 2, CV_64FC1, InvA );
cvInvert( &matA, &matInvA, CV_SVD );
cI2.x = (float)(cI.x + InvA[0]*bb1 + InvA[1]*bb2);
cI2.y = (float)(cI.y + InvA[2]*bb1 + InvA[3]*bb2);
}
err = (cI2.x - cI.x) * (cI2.x - cI.x) + (cI2.y - cI.y) * (cI2.y - cI.y);
cI = cI2;
}
while( ++iter < max_iters && err > eps );
/* if new point is too far from initial, it means poor convergence.
leave initial point as the result */
if( fabs( cI.x - cT.x ) > win.width || fabs( cI.y - cT.y ) > win.height )
{
cI = cT;
}
corners[pt_i] = cI; /* store result */
}
__CLEANUP__;
__END__;
cvFree( (void**)&buffer );
}
/* End of file. */