/*M///////////////////////////////////////////////////////////////////////////////////////
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// For Open Source Computer Vision Library
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//M*/
#include "_cv.h"
#define CONV( A, B, C) ( (float)( A + (B<<1) + C ) )
typedef struct
{
float xx;
float xy;
float yy;
float xt;
float yt;
float alpha; /* alpha = 1 / ( 1/lambda + xx + yy ) */
}
icvDerProductEx;
/*F///////////////////////////////////////////////////////////////////////////////////////
// Name: icvCalcOpticalFlowHS_8u32fR (Horn & Schunck method )
// Purpose: calculate Optical flow for 2 images using Horn & Schunck algorithm
// Context:
// Parameters:
// imgA - pointer to first frame ROI
// imgB - pointer to second frame ROI
// imgStep - width of single row of source images in bytes
// imgSize - size of the source image ROI
// usePrevious - use previous (input) velocity field.
// velocityX - pointer to horizontal and
// velocityY - vertical components of optical flow ROI
// velStep - width of single row of velocity frames in bytes
// lambda - Lagrangian multiplier
// criteria - criteria of termination processmaximum number of iterations
//
// Returns: CV_OK - all ok
// CV_OUTOFMEM_ERR - insufficient memory for function work
// CV_NULLPTR_ERR - if one of input pointers is NULL
// CV_BADSIZE_ERR - wrong input sizes interrelation
//
// Notes: 1.Optical flow to be computed for every pixel in ROI
// 2.For calculating spatial derivatives we use 3x3 Sobel operator.
// 3.We use the following border mode.
// The last row or column is replicated for the border
// ( IPL_BORDER_REPLICATE in IPL ).
//
//
//F*/
static CvStatus CV_STDCALL
icvCalcOpticalFlowHS_8u32fR( uchar* imgA,
uchar* imgB,
int imgStep,
CvSize imgSize,
int usePrevious,
float* velocityX,
float* velocityY,
int velStep,
float lambda,
CvTermCriteria criteria )
{
/* Loops indexes */
int i, j, k, address;
/* Buffers for Sobel calculations */
float *MemX[2];
float *MemY[2];
float ConvX, ConvY;
float GradX, GradY, GradT;
int imageWidth = imgSize.width;
int imageHeight = imgSize.height;
int ConvLine;
int LastLine;
int BufferSize;
float Ilambda = 1 / lambda;
int iter = 0;
int Stop;
/* buffers derivatives product */
icvDerProductEx *II;
float *VelBufX[2];
float *VelBufY[2];
/* variables for storing number of first pixel of image line */
int Line1;
int Line2;
int Line3;
int pixNumber;
/* auxiliary */
int NoMem = 0;
/* Checking bad arguments */
if( imgA == NULL )
return CV_NULLPTR_ERR;
if( imgB == NULL )
return CV_NULLPTR_ERR;
if( imgSize.width <= 0 )
return CV_BADSIZE_ERR;
if( imgSize.height <= 0 )
return CV_BADSIZE_ERR;
if( imgSize.width > imgStep )
return CV_BADSIZE_ERR;
if( (velStep & 3) != 0 )
return CV_BADSIZE_ERR;
velStep /= 4;
/****************************************************************************************/
/* Allocating memory for all buffers */
/****************************************************************************************/
for( k = 0; k < 2; k++ )
{
MemX[k] = (float *) cvAlloc( (imgSize.height) * sizeof( float ));
if( MemX[k] == NULL )
NoMem = 1;
MemY[k] = (float *) cvAlloc( (imgSize.width) * sizeof( float ));
if( MemY[k] == NULL )
NoMem = 1;
VelBufX[k] = (float *) cvAlloc( imageWidth * sizeof( float ));
if( VelBufX[k] == NULL )
NoMem = 1;
VelBufY[k] = (float *) cvAlloc( imageWidth * sizeof( float ));
if( VelBufY[k] == NULL )
NoMem = 1;
}
BufferSize = imageHeight * imageWidth;
II = (icvDerProductEx *) cvAlloc( BufferSize * sizeof( icvDerProductEx ));
if( (II == NULL) )
NoMem = 1;
if( NoMem )
{
for( k = 0; k < 2; k++ )
{
if( MemX[k] )
cvFree( &MemX[k] );
if( MemY[k] )
cvFree( &MemY[k] );
if( VelBufX[k] )
cvFree( &VelBufX[k] );
if( VelBufY[k] )
cvFree( &VelBufY[k] );
}
if( II )
cvFree( &II );
return CV_OUTOFMEM_ERR;
}
/****************************************************************************************\
* Calculate first line of memX and memY *
\****************************************************************************************/
MemY[0][0] = MemY[1][0] = CONV( imgA[0], imgA[0], imgA[1] );
MemX[0][0] = MemX[1][0] = CONV( imgA[0], imgA[0], imgA[imgStep] );
for( j = 1; j < imageWidth - 1; j++ )
{
MemY[0][j] = MemY[1][j] = CONV( imgA[j - 1], imgA[j], imgA[j + 1] );
}
pixNumber = imgStep;
for( i = 1; i < imageHeight - 1; i++ )
{
MemX[0][i] = MemX[1][i] = CONV( imgA[pixNumber - imgStep],
imgA[pixNumber], imgA[pixNumber + imgStep] );
pixNumber += imgStep;
}
MemY[0][imageWidth - 1] =
MemY[1][imageWidth - 1] = CONV( imgA[imageWidth - 2],
imgA[imageWidth - 1], imgA[imageWidth - 1] );
MemX[0][imageHeight - 1] =
MemX[1][imageHeight - 1] = CONV( imgA[pixNumber - imgStep],
imgA[pixNumber], imgA[pixNumber] );
/****************************************************************************************\
* begin scan image, calc derivatives *
\****************************************************************************************/
ConvLine = 0;
Line2 = -imgStep;
address = 0;
LastLine = imgStep * (imageHeight - 1);
while( ConvLine < imageHeight )
{
/*Here we calculate derivatives for line of image */
int memYline = (ConvLine + 1) & 1;
Line2 += imgStep;
Line1 = Line2 - ((Line2 == 0) ? 0 : imgStep);
Line3 = Line2 + ((Line2 == LastLine) ? 0 : imgStep);
/* Process first pixel */
ConvX = CONV( imgA[Line1 + 1], imgA[Line2 + 1], imgA[Line3 + 1] );
ConvY = CONV( imgA[Line3], imgA[Line3], imgA[Line3 + 1] );
GradY = (ConvY - MemY[memYline][0]) * 0.125f;
GradX = (ConvX - MemX[1][ConvLine]) * 0.125f;
MemY[memYline][0] = ConvY;
MemX[1][ConvLine] = ConvX;
GradT = (float) (imgB[Line2] - imgA[Line2]);
II[address].xx = GradX * GradX;
II[address].xy = GradX * GradY;
II[address].yy = GradY * GradY;
II[address].xt = GradX * GradT;
II[address].yt = GradY * GradT;
II[address].alpha = 1 / (Ilambda + II[address].xx + II[address].yy);
address++;
/* Process middle of line */
for( j = 1; j < imageWidth - 1; j++ )
{
ConvX = CONV( imgA[Line1 + j + 1], imgA[Line2 + j + 1], imgA[Line3 + j + 1] );
ConvY = CONV( imgA[Line3 + j - 1], imgA[Line3 + j], imgA[Line3 + j + 1] );
GradY = (ConvY - MemY[memYline][j]) * 0.125f;
GradX = (ConvX - MemX[(j - 1) & 1][ConvLine]) * 0.125f;
MemY[memYline][j] = ConvY;
MemX[(j - 1) & 1][ConvLine] = ConvX;
GradT = (float) (imgB[Line2 + j] - imgA[Line2 + j]);
II[address].xx = GradX * GradX;
II[address].xy = GradX * GradY;
II[address].yy = GradY * GradY;
II[address].xt = GradX * GradT;
II[address].yt = GradY * GradT;
II[address].alpha = 1 / (Ilambda + II[address].xx + II[address].yy);
address++;
}
/* Process last pixel of line */
ConvX = CONV( imgA[Line1 + imageWidth - 1], imgA[Line2 + imageWidth - 1],
imgA[Line3 + imageWidth - 1] );
ConvY = CONV( imgA[Line3 + imageWidth - 2], imgA[Line3 + imageWidth - 1],
imgA[Line3 + imageWidth - 1] );
GradY = (ConvY - MemY[memYline][imageWidth - 1]) * 0.125f;
GradX = (ConvX - MemX[(imageWidth - 2) & 1][ConvLine]) * 0.125f;
MemY[memYline][imageWidth - 1] = ConvY;
GradT = (float) (imgB[Line2 + imageWidth - 1] - imgA[Line2 + imageWidth - 1]);
II[address].xx = GradX * GradX;
II[address].xy = GradX * GradY;
II[address].yy = GradY * GradY;
II[address].xt = GradX * GradT;
II[address].yt = GradY * GradT;
II[address].alpha = 1 / (Ilambda + II[address].xx + II[address].yy);
address++;
ConvLine++;
}
/****************************************************************************************\
* Prepare initial approximation *
\****************************************************************************************/
if( !usePrevious )
{
float *vx = velocityX;
float *vy = velocityY;
for( i = 0; i < imageHeight; i++ )
{
memset( vx, 0, imageWidth * sizeof( float ));
memset( vy, 0, imageWidth * sizeof( float ));
vx += velStep;
vy += velStep;
}
}
/****************************************************************************************\
* Perform iterations *
\****************************************************************************************/
iter = 0;
Stop = 0;
LastLine = velStep * (imageHeight - 1);
while( !Stop )
{
float Eps = 0;
address = 0;
iter++;
/****************************************************************************************\
* begin scan velocity and update it *
\****************************************************************************************/
Line2 = -velStep;
for( i = 0; i < imageHeight; i++ )
{
/* Here average velocity */
float averageX;
float averageY;
float tmp;
Line2 += velStep;
Line1 = Line2 - ((Line2 == 0) ? 0 : velStep);
Line3 = Line2 + ((Line2 == LastLine) ? 0 : velStep);
/* Process first pixel */
averageX = (velocityX[Line2] +
velocityX[Line2 + 1] + velocityX[Line1] + velocityX[Line3]) / 4;
averageY = (velocityY[Line2] +
velocityY[Line2 + 1] + velocityY[Line1] + velocityY[Line3]) / 4;
VelBufX[i & 1][0] = averageX -
(II[address].xx * averageX +
II[address].xy * averageY + II[address].xt) * II[address].alpha;
VelBufY[i & 1][0] = averageY -
(II[address].xy * averageX +
II[address].yy * averageY + II[address].yt) * II[address].alpha;
/* update Epsilon */
if( criteria.type & CV_TERMCRIT_EPS )
{
tmp = (float)fabs(velocityX[Line2] - VelBufX[i & 1][0]);
Eps = MAX( tmp, Eps );
tmp = (float)fabs(velocityY[Line2] - VelBufY[i & 1][0]);
Eps = MAX( tmp, Eps );
}
address++;
/* Process middle of line */
for( j = 1; j < imageWidth - 1; j++ )
{
averageX = (velocityX[Line2 + j - 1] +
velocityX[Line2 + j + 1] +
velocityX[Line1 + j] + velocityX[Line3 + j]) / 4;
averageY = (velocityY[Line2 + j - 1] +
velocityY[Line2 + j + 1] +
velocityY[Line1 + j] + velocityY[Line3 + j]) / 4;
VelBufX[i & 1][j] = averageX -
(II[address].xx * averageX +
II[address].xy * averageY + II[address].xt) * II[address].alpha;
VelBufY[i & 1][j] = averageY -
(II[address].xy * averageX +
II[address].yy * averageY + II[address].yt) * II[address].alpha;
/* update Epsilon */
if( criteria.type & CV_TERMCRIT_EPS )
{
tmp = (float)fabs(velocityX[Line2 + j] - VelBufX[i & 1][j]);
Eps = MAX( tmp, Eps );
tmp = (float)fabs(velocityY[Line2 + j] - VelBufY[i & 1][j]);
Eps = MAX( tmp, Eps );
}
address++;
}
/* Process last pixel of line */
averageX = (velocityX[Line2 + imageWidth - 2] +
velocityX[Line2 + imageWidth - 1] +
velocityX[Line1 + imageWidth - 1] +
velocityX[Line3 + imageWidth - 1]) / 4;
averageY = (velocityY[Line2 + imageWidth - 2] +
velocityY[Line2 + imageWidth - 1] +
velocityY[Line1 + imageWidth - 1] +
velocityY[Line3 + imageWidth - 1]) / 4;
VelBufX[i & 1][imageWidth - 1] = averageX -
(II[address].xx * averageX +
II[address].xy * averageY + II[address].xt) * II[address].alpha;
VelBufY[i & 1][imageWidth - 1] = averageY -
(II[address].xy * averageX +
II[address].yy * averageY + II[address].yt) * II[address].alpha;
/* update Epsilon */
if( criteria.type & CV_TERMCRIT_EPS )
{
tmp = (float)fabs(velocityX[Line2 + imageWidth - 1] -
VelBufX[i & 1][imageWidth - 1]);
Eps = MAX( tmp, Eps );
tmp = (float)fabs(velocityY[Line2 + imageWidth - 1] -
VelBufY[i & 1][imageWidth - 1]);
Eps = MAX( tmp, Eps );
}
address++;
/* store new velocity from old buffer to velocity frame */
if( i > 0 )
{
memcpy( &velocityX[Line1], VelBufX[(i - 1) & 1], imageWidth * sizeof( float ));
memcpy( &velocityY[Line1], VelBufY[(i - 1) & 1], imageWidth * sizeof( float ));
}
} /*for */
/* store new velocity from old buffer to velocity frame */
memcpy( &velocityX[imageWidth * (imageHeight - 1)],
VelBufX[(imageHeight - 1) & 1], imageWidth * sizeof( float ));
memcpy( &velocityY[imageWidth * (imageHeight - 1)],
VelBufY[(imageHeight - 1) & 1], imageWidth * sizeof( float ));
if( (criteria.type & CV_TERMCRIT_ITER) && (iter == criteria.max_iter) )
Stop = 1;
if( (criteria.type & CV_TERMCRIT_EPS) && (Eps < criteria.epsilon) )
Stop = 1;
}
/* Free memory */
for( k = 0; k < 2; k++ )
{
cvFree( &MemX[k] );
cvFree( &MemY[k] );
cvFree( &VelBufX[k] );
cvFree( &VelBufY[k] );
}
cvFree( &II );
return CV_OK;
} /*icvCalcOpticalFlowHS_8u32fR*/
/*F///////////////////////////////////////////////////////////////////////////////////////
// Name: cvCalcOpticalFlowHS
// Purpose: Optical flow implementation
// Context:
// Parameters:
// srcA, srcB - source image
// velx, vely - destination image
// Returns:
//
// Notes:
//F*/
CV_IMPL void
cvCalcOpticalFlowHS( const void* srcarrA, const void* srcarrB, int usePrevious,
void* velarrx, void* velarry,
double lambda, CvTermCriteria criteria )
{
CV_FUNCNAME( "cvCalcOpticalFlowHS" );
__BEGIN__;
CvMat stubA, *srcA = (CvMat*)srcarrA;
CvMat stubB, *srcB = (CvMat*)srcarrB;
CvMat stubx, *velx = (CvMat*)velarrx;
CvMat stuby, *vely = (CvMat*)velarry;
CV_CALL( srcA = cvGetMat( srcA, &stubA ));
CV_CALL( srcB = cvGetMat( srcB, &stubB ));
CV_CALL( velx = cvGetMat( velx, &stubx ));
CV_CALL( vely = cvGetMat( vely, &stuby ));
if( !CV_ARE_TYPES_EQ( srcA, srcB ))
CV_ERROR( CV_StsUnmatchedFormats, "Source images have different formats" );
if( !CV_ARE_TYPES_EQ( velx, vely ))
CV_ERROR( CV_StsUnmatchedFormats, "Destination images have different formats" );
if( !CV_ARE_SIZES_EQ( srcA, srcB ) ||
!CV_ARE_SIZES_EQ( velx, vely ) ||
!CV_ARE_SIZES_EQ( srcA, velx ))
CV_ERROR( CV_StsUnmatchedSizes, "" );
if( CV_MAT_TYPE( srcA->type ) != CV_8UC1 ||
CV_MAT_TYPE( velx->type ) != CV_32FC1 )
CV_ERROR( CV_StsUnsupportedFormat, "Source images must have 8uC1 type and "
"destination images must have 32fC1 type" );
if( srcA->step != srcB->step || velx->step != vely->step )
CV_ERROR( CV_BadStep, "source and destination images have different step" );
IPPI_CALL( icvCalcOpticalFlowHS_8u32fR( (uchar*)srcA->data.ptr, (uchar*)srcB->data.ptr,
srcA->step, cvGetMatSize( srcA ), usePrevious,
velx->data.fl, vely->data.fl,
velx->step, (float)lambda, criteria ));
__END__;
}
/* End of file. */