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added minEigThreshold parameter to calcOpticalFlowPyrLK to filter out bad points earlier.

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This commit is contained in:
Vadim Pisarevsky 2011-07-27 19:07:45 +00:00
parent 6b5ea5931d
commit eebe4860da
3 changed files with 56 additions and 11 deletions
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5
modules/video/include/opencv2/video/tracking.hpp
View File

@ -318,12 +318,13 @@ enum { OPTFLOW_USE_INITIAL_FLOW=4, OPTFLOW_FARNEBACK_GAUSSIAN=256 };
CV_EXPORTS_W void calcOpticalFlowPyrLK( InputArray prevImg, InputArray nextImg,
InputArray prevPts, CV_OUT InputOutputArray nextPts,
OutputArray status, OutputArray err,
Size winSize=Size(15,15), int maxLevel=3,
Size winSize=Size(21,21), int maxLevel=3,
TermCriteria criteria=TermCriteria(
TermCriteria::COUNT+TermCriteria::EPS,
30, 0.01),
double derivLambda=0.5,
int flags=0 );
int flags=0,
double minEigThreshold=1e-4);
//! computes dense optical flow using Farneback algorithm
CV_EXPORTS_W void calcOpticalFlowFarneback( InputArray prev, InputArray next,

56
modules/video/src/lkpyramid.cpp
View File

@ -134,7 +134,7 @@ struct LKTrackerInvoker
const Point2f* _prevPts, Point2f* _nextPts,
uchar* _status, float* _err,
Size _winSize, TermCriteria _criteria,
int _level, int _maxLevel, int _flags )
int _level, int _maxLevel, int _flags, float _minEigThreshold )
{
prevImg = &_prevImg;
prevDeriv = &_prevDeriv;
@ -148,6 +148,7 @@ struct LKTrackerInvoker
level = _level;
maxLevel = _maxLevel;
flags = _flags;
minEigThreshold = _minEigThreshold;
}
void operator()(const BlockedRange& range) const
@ -308,11 +309,12 @@ struct LKTrackerInvoker
float D = A11*A22 - A12*A12;
float minEig = (A22 + A11 - std::sqrt((A11-A22)*(A11-A22) +
4.f*A12*A12))/(2*winSize.width*winSize.height);
if( err )
4.f*A12*A12))/(2*winSize.width*winSize.height);
if( err && (flags & CV_LKFLOW_GET_MIN_EIGENVALS) != 0 )
err[ptidx] = (float)minEig;
if( D < FLT_EPSILON )
if( minEig < minEigThreshold || D < FLT_EPSILON )
{
if( level == 0 && status )
status[ptidx] = false;
@ -431,6 +433,46 @@ struct LKTrackerInvoker
}
prevDelta = delta;
}
if( status[ptidx] && err && level == 0 && (flags & CV_LKFLOW_GET_MIN_EIGENVALS) == 0 )
{
Point2f nextPt = nextPts[ptidx];
Point inextPt;
inextPt.x = cvFloor(nextPt.x);
inextPt.y = cvFloor(nextPt.y);
if( inextPt.x < -winSize.width || inextPt.x >= J.cols ||
inextPt.y < -winSize.height || inextPt.y >= J.rows )
{
if( status )
status[ptidx] = false;
continue;
}
float a = nextPt.x - inextPt.x;
float b = nextPt.y - inextPt.y;
iw00 = cvRound((1.f - a)*(1.f - b)*(1 << W_BITS));
iw01 = cvRound(a*(1.f - b)*(1 << W_BITS));
iw10 = cvRound((1.f - a)*b*(1 << W_BITS));
iw11 = (1 << W_BITS) - iw00 - iw01 - iw10;
float errval = 0.f;
for( y = 0; y < winSize.height; y++ )
{
const uchar* Jptr = (const uchar*)J.data + (y + inextPt.y)*step + inextPt.x*cn;
const deriv_type* Iptr = (const deriv_type*)(IWinBuf.data + y*IWinBuf.step);
for( x = 0; x < winSize.width*cn; x++ )
{
int diff = CV_DESCALE(Jptr[x]*iw00 + Jptr[x+cn]*iw01 +
Jptr[x+step]*iw10 + Jptr[x+step+cn]*iw11,
W_BITS1-5) - Iptr[x];
errval += std::abs((float)diff);
}
}
err[ptidx] = errval * 1.f/(32*winSize.width*cn*winSize.height);
}
}
}
@ -446,6 +488,7 @@ struct LKTrackerInvoker
int level;
int maxLevel;
int flags;
float minEigThreshold;
};
}
@ -456,7 +499,7 @@ void cv::calcOpticalFlowPyrLK( InputArray _prevImg, InputArray _nextImg,
Size winSize, int maxLevel,
TermCriteria criteria,
double derivLambda,
int flags )
int flags, double minEigThreshold )
{
#ifdef HAVE_TEGRA_OPTIMIZATION
if (tegra::calcOpticalFlowPyrLK(_prevImg, _nextImg, _prevPts, _nextPts, _status, _err, winSize, maxLevel, criteria, derivLambda, flags))
@ -570,7 +613,8 @@ void cv::calcOpticalFlowPyrLK( InputArray _prevImg, InputArray _nextImg,
parallel_for(BlockedRange(0, npoints), LKTrackerInvoker(prevPyr[level], derivI,
nextPyr[level], prevPts, nextPts,
status, err,
winSize, criteria, level, maxLevel, flags));
winSize, criteria, level, maxLevel,
flags, (float)minEigThreshold));
}
}

6
samples/cpp/lkdemo.cpp
View File

@ -39,7 +39,7 @@ int main( int argc, char** argv )
{
VideoCapture cap;
TermCriteria termcrit(CV_TERMCRIT_ITER|CV_TERMCRIT_EPS,20,0.03);
Size winSize(10,10);
Size subPixWinSize(10,10), winSize(31,31);
const int MAX_COUNT = 500;
bool needToInit = false;
@ -81,7 +81,7 @@ int main( int argc, char** argv )
{
// automatic initialization
goodFeaturesToTrack(gray, points[1], MAX_COUNT, 0.01, 10, Mat(), 3, 0, 0.04);
cornerSubPix(gray, points[1], winSize, Size(-1,-1), termcrit);
cornerSubPix(gray, points[1], subPixWinSize, Size(-1,-1), termcrit);
addRemovePt = false;
}
else if( !points[0].empty() )
@ -91,7 +91,7 @@ int main( int argc, char** argv )
if(prevGray.empty())
gray.copyTo(prevGray);
calcOpticalFlowPyrLK(prevGray, gray, points[0], points[1], status, err, winSize,
3, termcrit, 0);
3, termcrit, 0, 0, 0.001);
size_t i, k;
for( i = k = 0; i < points[1].size(); i++ )
{