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#include "precomp.hpp"
using namespace cv;
using namespace cv::cuda;
#if !defined HAVE_CUDA || defined(CUDA_DISABLER)
void cv::cuda::calcOpticalFlowBM(const GpuMat&, const GpuMat&, Size, Size, Size, bool, GpuMat&, GpuMat&, GpuMat&, Stream&) { throw_no_cuda(); }
#else // HAVE_CUDA
namespace optflowbm
{
void calc(PtrStepSzb prev, PtrStepSzb curr, PtrStepSzf velx, PtrStepSzf vely, int2 blockSize, int2 shiftSize, bool usePrevious,
int maxX, int maxY, int acceptLevel, int escapeLevel, const short2* ss, int ssCount, cudaStream_t stream);
}
void cv::cuda::calcOpticalFlowBM(const GpuMat& prev, const GpuMat& curr, Size blockSize, Size shiftSize, Size maxRange, bool usePrevious, GpuMat& velx, GpuMat& vely, GpuMat& buf, Stream& st)
{
CV_Assert( prev.type() == CV_8UC1 );
CV_Assert( curr.size() == prev.size() && curr.type() == prev.type() );
const Size velSize((prev.cols - blockSize.width + shiftSize.width) / shiftSize.width,
(prev.rows - blockSize.height + shiftSize.height) / shiftSize.height);
velx.create(velSize, CV_32FC1);
vely.create(velSize, CV_32FC1);
// scanning scheme coordinates
std::vector<short2> ss((2 * maxRange.width + 1) * (2 * maxRange.height + 1));
int ssCount = 0;
// Calculate scanning scheme
const int minCount = std::min(maxRange.width, maxRange.height);
// use spiral search pattern
//
// 9 10 11 12
// 8 1 2 13
// 7 * 3 14
// 6 5 4 15
//... 20 19 18 17
//
for (int i = 0; i < minCount; ++i)
{
// four cycles along sides
int x = -i - 1, y = x;
// upper side
for (int j = -i; j <= i + 1; ++j, ++ssCount)
{
ss[ssCount].x = (short) ++x;
ss[ssCount].y = (short) y;
}
// right side
for (int j = -i; j <= i + 1; ++j, ++ssCount)
{
ss[ssCount].x = (short) x;
ss[ssCount].y = (short) ++y;
}
// bottom side
for (int j = -i; j <= i + 1; ++j, ++ssCount)
{
ss[ssCount].x = (short) --x;
ss[ssCount].y = (short) y;
}
// left side
for (int j = -i; j <= i + 1; ++j, ++ssCount)
{
ss[ssCount].x = (short) x;
ss[ssCount].y = (short) --y;
}
}
// the rest part
if (maxRange.width < maxRange.height)
{
const int xleft = -minCount;
// cycle by neighbor rings
for (int i = minCount; i < maxRange.height; ++i)
{
// two cycles by x
int y = -(i + 1);
int x = xleft;
// upper side
for (int j = -maxRange.width; j <= maxRange.width; ++j, ++ssCount, ++x)
{
ss[ssCount].x = (short) x;
ss[ssCount].y = (short) y;
}
x = xleft;
y = -y;
// bottom side
for (int j = -maxRange.width; j <= maxRange.width; ++j, ++ssCount, ++x)
{
ss[ssCount].x = (short) x;
ss[ssCount].y = (short) y;
}
}
}
else if (maxRange.width > maxRange.height)
{
const int yupper = -minCount;
// cycle by neighbor rings
for (int i = minCount; i < maxRange.width; ++i)
{
// two cycles by y
int x = -(i + 1);
int y = yupper;
// left side
for (int j = -maxRange.height; j <= maxRange.height; ++j, ++ssCount, ++y)
{
ss[ssCount].x = (short) x;
ss[ssCount].y = (short) y;
}
y = yupper;
x = -x;
// right side
for (int j = -maxRange.height; j <= maxRange.height; ++j, ++ssCount, ++y)
{
ss[ssCount].x = (short) x;
ss[ssCount].y = (short) y;
}
}
}
const cudaStream_t stream = StreamAccessor::getStream(st);
ensureSizeIsEnough(1, ssCount, CV_16SC2, buf);
if (stream == 0)
cudaSafeCall( cudaMemcpy(buf.data, &ss[0], ssCount * sizeof(short2), cudaMemcpyHostToDevice) );
else
cudaSafeCall( cudaMemcpyAsync(buf.data, &ss[0], ssCount * sizeof(short2), cudaMemcpyHostToDevice, stream) );
const int maxX = prev.cols - blockSize.width;
const int maxY = prev.rows - blockSize.height;
const int SMALL_DIFF = 2;
const int BIG_DIFF = 128;
const int blSize = blockSize.area();
const int acceptLevel = blSize * SMALL_DIFF;
const int escapeLevel = blSize * BIG_DIFF;
optflowbm::calc(prev, curr, velx, vely,
make_int2(blockSize.width, blockSize.height), make_int2(shiftSize.width, shiftSize.height), usePrevious,
maxX, maxY, acceptLevel, escapeLevel, buf.ptr<short2>(), ssCount, stream);
}
#endif // HAVE_CUDA