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// License Agreement
// For Open Source Computer Vision Library
//
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#if !defined CUDA_DISABLER
#include "opencv2/core/cuda/common.hpp"
#include "opencv2/core/cuda/reduce.hpp"
#include "opencv2/core/cuda/functional.hpp"
#include "opencv2/core/cuda/warp_shuffle.hpp"
namespace cv { namespace cuda { namespace device
{
// Other values are not supported
#define CELL_WIDTH 8
#define CELL_HEIGHT 8
#define CELLS_PER_BLOCK_X 2
#define CELLS_PER_BLOCK_Y 2
namespace hog
{
__constant__ int cnbins;
__constant__ int cblock_stride_x;
__constant__ int cblock_stride_y;
__constant__ int cnblocks_win_x;
__constant__ int cnblocks_win_y;
__constant__ int cblock_hist_size;
__constant__ int cblock_hist_size_2up;
__constant__ int cdescr_size;
__constant__ int cdescr_width;
/* Returns the nearest upper power of two, works only for
the typical GPU thread count (pert block) values */
int power_2up(unsigned int n)
{
if (n < 1) return 1;
else if (n < 2) return 2;
else if (n < 4) return 4;
else if (n < 8) return 8;
else if (n < 16) return 16;
else if (n < 32) return 32;
else if (n < 64) return 64;
else if (n < 128) return 128;
else if (n < 256) return 256;
else if (n < 512) return 512;
else if (n < 1024) return 1024;
return -1; // Input is too big
}
void set_up_constants(int nbins, int block_stride_x, int block_stride_y,
int nblocks_win_x, int nblocks_win_y)
{
cudaSafeCall( cudaMemcpyToSymbol(cnbins, &nbins, sizeof(nbins)) );
cudaSafeCall( cudaMemcpyToSymbol(cblock_stride_x, &block_stride_x, sizeof(block_stride_x)) );
cudaSafeCall( cudaMemcpyToSymbol(cblock_stride_y, &block_stride_y, sizeof(block_stride_y)) );
cudaSafeCall( cudaMemcpyToSymbol(cnblocks_win_x, &nblocks_win_x, sizeof(nblocks_win_x)) );
cudaSafeCall( cudaMemcpyToSymbol(cnblocks_win_y, &nblocks_win_y, sizeof(nblocks_win_y)) );
int block_hist_size = nbins * CELLS_PER_BLOCK_X * CELLS_PER_BLOCK_Y;
cudaSafeCall( cudaMemcpyToSymbol(cblock_hist_size, &block_hist_size, sizeof(block_hist_size)) );
int block_hist_size_2up = power_2up(block_hist_size);
cudaSafeCall( cudaMemcpyToSymbol(cblock_hist_size_2up, &block_hist_size_2up, sizeof(block_hist_size_2up)) );
int descr_width = nblocks_win_x * block_hist_size;
cudaSafeCall( cudaMemcpyToSymbol(cdescr_width, &descr_width, sizeof(descr_width)) );
int descr_size = descr_width * nblocks_win_y;
cudaSafeCall( cudaMemcpyToSymbol(cdescr_size, &descr_size, sizeof(descr_size)) );
}
//----------------------------------------------------------------------------
// Histogram computation
template <int nblocks> // Number of histogram blocks processed by single GPU thread block
__global__ void compute_hists_kernel_many_blocks(const int img_block_width, const PtrStepf grad,
const PtrStepb qangle, float scale, float* block_hists)
{
const int block_x = threadIdx.z;
const int cell_x = threadIdx.x / 16;
const int cell_y = threadIdx.y;
const int cell_thread_x = threadIdx.x & 0xF;
if (blockIdx.x * blockDim.z + block_x >= img_block_width)
return;
extern __shared__ float smem[];
float* hists = smem;
float* final_hist = smem + cnbins * 48 * nblocks;
const int offset_x = (blockIdx.x * blockDim.z + block_x) * cblock_stride_x +
4 * cell_x + cell_thread_x;
const int offset_y = blockIdx.y * cblock_stride_y + 4 * cell_y;
const float* grad_ptr = grad.ptr(offset_y) + offset_x * 2;
const unsigned char* qangle_ptr = qangle.ptr(offset_y) + offset_x * 2;
// 12 means that 12 pixels affect on block's cell (in one row)
if (cell_thread_x < 12)
{
float* hist = hists + 12 * (cell_y * blockDim.z * CELLS_PER_BLOCK_Y +
cell_x + block_x * CELLS_PER_BLOCK_X) +
cell_thread_x;
for (int bin_id = 0; bin_id < cnbins; ++bin_id)
hist[bin_id * 48 * nblocks] = 0.f;
const int dist_x = -4 + (int)cell_thread_x - 4 * cell_x;
const int dist_y_begin = -4 - 4 * (int)threadIdx.y;
for (int dist_y = dist_y_begin; dist_y < dist_y_begin + 12; ++dist_y)
{
float2 vote = *(const float2*)grad_ptr;
uchar2 bin = *(const uchar2*)qangle_ptr;
grad_ptr += grad.step/sizeof(float);
qangle_ptr += qangle.step;
int dist_center_y = dist_y - 4 * (1 - 2 * cell_y);
int dist_center_x = dist_x - 4 * (1 - 2 * cell_x);
float gaussian = ::expf(-(dist_center_y * dist_center_y +
dist_center_x * dist_center_x) * scale);
float interp_weight = (8.f - ::fabs(dist_y + 0.5f)) *
(8.f - ::fabs(dist_x + 0.5f)) / 64.f;
hist[bin.x * 48 * nblocks] += gaussian * interp_weight * vote.x;
hist[bin.y * 48 * nblocks] += gaussian * interp_weight * vote.y;
}
volatile float* hist_ = hist;
for (int bin_id = 0; bin_id < cnbins; ++bin_id, hist_ += 48 * nblocks)
{
if (cell_thread_x < 6) hist_[0] += hist_[6];
if (cell_thread_x < 3) hist_[0] += hist_[3];
if (cell_thread_x == 0)
final_hist[((cell_x + block_x * 2) * 2 + cell_y) * cnbins + bin_id]
= hist_[0] + hist_[1] + hist_[2];
}
}
__syncthreads();
float* block_hist = block_hists + (blockIdx.y * img_block_width +
blockIdx.x * blockDim.z + block_x) *
cblock_hist_size;
int tid = (cell_y * CELLS_PER_BLOCK_Y + cell_x) * 16 + cell_thread_x;
if (tid < cblock_hist_size)
block_hist[tid] = final_hist[block_x * cblock_hist_size + tid];
}
void compute_hists(int nbins, int block_stride_x, int block_stride_y,
int height, int width, const PtrStepSzf& grad,
const PtrStepSzb& qangle, float sigma, float* block_hists)
{
const int nblocks = 1;
int img_block_width = (width - CELLS_PER_BLOCK_X * CELL_WIDTH + block_stride_x) /
block_stride_x;
int img_block_height = (height - CELLS_PER_BLOCK_Y * CELL_HEIGHT + block_stride_y) /
block_stride_y;
dim3 grid(divUp(img_block_width, nblocks), img_block_height);
dim3 threads(32, 2, nblocks);
cudaSafeCall(cudaFuncSetCacheConfig(compute_hists_kernel_many_blocks<nblocks>,
cudaFuncCachePreferL1));
// Precompute gaussian spatial window parameter
float scale = 1.f / (2.f * sigma * sigma);
int hists_size = (nbins * CELLS_PER_BLOCK_X * CELLS_PER_BLOCK_Y * 12 * nblocks) * sizeof(float);
int final_hists_size = (nbins * CELLS_PER_BLOCK_X * CELLS_PER_BLOCK_Y * nblocks) * sizeof(float);
int smem = hists_size + final_hists_size;
compute_hists_kernel_many_blocks<nblocks><<<grid, threads, smem>>>(
img_block_width, grad, qangle, scale, block_hists);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
//-------------------------------------------------------------
// Normalization of histograms via L2Hys_norm
//
template<int size>
__device__ float reduce_smem(float* smem, float val)
{
unsigned int tid = threadIdx.x;
float sum = val;
reduce<size>(smem, sum, tid, plus<float>());
if (size == 32)
{
#if __CUDA_ARCH__ >= 300
return shfl(sum, 0);
#else
return smem[0];
#endif
}
else
{
#if __CUDA_ARCH__ >= 300
if (threadIdx.x == 0)
smem[0] = sum;
#endif
__syncthreads();
return smem[0];
}
}
template <int nthreads, // Number of threads which process one block historgam
int nblocks> // Number of block hisograms processed by one GPU thread block
__global__ void normalize_hists_kernel_many_blocks(const int block_hist_size,
const int img_block_width,
float* block_hists, float threshold)
{
if (blockIdx.x * blockDim.z + threadIdx.z >= img_block_width)
return;
float* hist = block_hists + (blockIdx.y * img_block_width +
blockIdx.x * blockDim.z + threadIdx.z) *
block_hist_size + threadIdx.x;
__shared__ float sh_squares[nthreads * nblocks];
float* squares = sh_squares + threadIdx.z * nthreads;
float elem = 0.f;
if (threadIdx.x < block_hist_size)
elem = hist[0];
float sum = reduce_smem<nthreads>(squares, elem * elem);
float scale = 1.0f / (::sqrtf(sum) + 0.1f * block_hist_size);
elem = ::min(elem * scale, threshold);
sum = reduce_smem<nthreads>(squares, elem * elem);
scale = 1.0f / (::sqrtf(sum) + 1e-3f);
if (threadIdx.x < block_hist_size)
hist[0] = elem * scale;
}
void normalize_hists(int nbins, int block_stride_x, int block_stride_y,
int height, int width, float* block_hists, float threshold)
{
const int nblocks = 1;
int block_hist_size = nbins * CELLS_PER_BLOCK_X * CELLS_PER_BLOCK_Y;
int nthreads = power_2up(block_hist_size);
dim3 threads(nthreads, 1, nblocks);
int img_block_width = (width - CELLS_PER_BLOCK_X * CELL_WIDTH + block_stride_x) / block_stride_x;
int img_block_height = (height - CELLS_PER_BLOCK_Y * CELL_HEIGHT + block_stride_y) / block_stride_y;
dim3 grid(divUp(img_block_width, nblocks), img_block_height);
if (nthreads == 32)
normalize_hists_kernel_many_blocks<32, nblocks><<<grid, threads>>>(block_hist_size, img_block_width, block_hists, threshold);
else if (nthreads == 64)
normalize_hists_kernel_many_blocks<64, nblocks><<<grid, threads>>>(block_hist_size, img_block_width, block_hists, threshold);
else if (nthreads == 128)
normalize_hists_kernel_many_blocks<64, nblocks><<<grid, threads>>>(block_hist_size, img_block_width, block_hists, threshold);
else if (nthreads == 256)
normalize_hists_kernel_many_blocks<256, nblocks><<<grid, threads>>>(block_hist_size, img_block_width, block_hists, threshold);
else if (nthreads == 512)
normalize_hists_kernel_many_blocks<512, nblocks><<<grid, threads>>>(block_hist_size, img_block_width, block_hists, threshold);
else
CV_Error(cv::Error::StsBadArg, "normalize_hists: histogram's size is too big, try to decrease number of bins");
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
//---------------------------------------------------------------------
// Linear SVM based classification
//
// return confidence values not just positive location
template <int nthreads, // Number of threads per one histogram block
int nblocks> // Number of histogram block processed by single GPU thread block
__global__ void compute_confidence_hists_kernel_many_blocks(const int img_win_width, const int img_block_width,
const int win_block_stride_x, const int win_block_stride_y,
const float* block_hists, const float* coefs,
float free_coef, float threshold, float* confidences)
{
const int win_x = threadIdx.z;
if (blockIdx.x * blockDim.z + win_x >= img_win_width)
return;
const float* hist = block_hists + (blockIdx.y * win_block_stride_y * img_block_width +
blockIdx.x * win_block_stride_x * blockDim.z + win_x) *
cblock_hist_size;
float product = 0.f;
for (int i = threadIdx.x; i < cdescr_size; i += nthreads)
{
int offset_y = i / cdescr_width;
int offset_x = i - offset_y * cdescr_width;
product += coefs[i] * hist[offset_y * img_block_width * cblock_hist_size + offset_x];
}
__shared__ float products[nthreads * nblocks];
const int tid = threadIdx.z * nthreads + threadIdx.x;
reduce<nthreads>(products, product, tid, plus<float>());
if (threadIdx.x == 0)
confidences[blockIdx.y * img_win_width + blockIdx.x * blockDim.z + win_x] = product + free_coef;
}
void compute_confidence_hists(int win_height, int win_width, int block_stride_y, int block_stride_x,
int win_stride_y, int win_stride_x, int height, int width, float* block_hists,
float* coefs, float free_coef, float threshold, float *confidences)
{
const int nthreads = 256;
const int nblocks = 1;
int win_block_stride_x = win_stride_x / block_stride_x;
int win_block_stride_y = win_stride_y / block_stride_y;
int img_win_width = (width - win_width + win_stride_x) / win_stride_x;
int img_win_height = (height - win_height + win_stride_y) / win_stride_y;
dim3 threads(nthreads, 1, nblocks);
dim3 grid(divUp(img_win_width, nblocks), img_win_height);
cudaSafeCall(cudaFuncSetCacheConfig(compute_confidence_hists_kernel_many_blocks<nthreads, nblocks>,
cudaFuncCachePreferL1));
int img_block_width = (width - CELLS_PER_BLOCK_X * CELL_WIDTH + block_stride_x) /
block_stride_x;
compute_confidence_hists_kernel_many_blocks<nthreads, nblocks><<<grid, threads>>>(
img_win_width, img_block_width, win_block_stride_x, win_block_stride_y,
block_hists, coefs, free_coef, threshold, confidences);
cudaSafeCall(cudaThreadSynchronize());
}
template <int nthreads, // Number of threads per one histogram block
int nblocks> // Number of histogram block processed by single GPU thread block
__global__ void classify_hists_kernel_many_blocks(const int img_win_width, const int img_block_width,
const int win_block_stride_x, const int win_block_stride_y,
const float* block_hists, const float* coefs,
float free_coef, float threshold, unsigned char* labels)
{
const int win_x = threadIdx.z;
if (blockIdx.x * blockDim.z + win_x >= img_win_width)
return;
const float* hist = block_hists + (blockIdx.y * win_block_stride_y * img_block_width +
blockIdx.x * win_block_stride_x * blockDim.z + win_x) *
cblock_hist_size;
float product = 0.f;
for (int i = threadIdx.x; i < cdescr_size; i += nthreads)
{
int offset_y = i / cdescr_width;
int offset_x = i - offset_y * cdescr_width;
product += coefs[i] * hist[offset_y * img_block_width * cblock_hist_size + offset_x];
}
__shared__ float products[nthreads * nblocks];
const int tid = threadIdx.z * nthreads + threadIdx.x;
reduce<nthreads>(products, product, tid, plus<float>());
if (threadIdx.x == 0)
labels[blockIdx.y * img_win_width + blockIdx.x * blockDim.z + win_x] = (product + free_coef >= threshold);
}
void classify_hists(int win_height, int win_width, int block_stride_y, int block_stride_x,
int win_stride_y, int win_stride_x, int height, int width, float* block_hists,
float* coefs, float free_coef, float threshold, unsigned char* labels)
{
const int nthreads = 256;
const int nblocks = 1;
int win_block_stride_x = win_stride_x / block_stride_x;
int win_block_stride_y = win_stride_y / block_stride_y;
int img_win_width = (width - win_width + win_stride_x) / win_stride_x;
int img_win_height = (height - win_height + win_stride_y) / win_stride_y;
dim3 threads(nthreads, 1, nblocks);
dim3 grid(divUp(img_win_width, nblocks), img_win_height);
cudaSafeCall(cudaFuncSetCacheConfig(classify_hists_kernel_many_blocks<nthreads, nblocks>, cudaFuncCachePreferL1));
int img_block_width = (width - CELLS_PER_BLOCK_X * CELL_WIDTH + block_stride_x) / block_stride_x;
classify_hists_kernel_many_blocks<nthreads, nblocks><<<grid, threads>>>(
img_win_width, img_block_width, win_block_stride_x, win_block_stride_y,
block_hists, coefs, free_coef, threshold, labels);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
//----------------------------------------------------------------------------
// Extract descriptors
template <int nthreads>
__global__ void extract_descrs_by_rows_kernel(const int img_block_width, const int win_block_stride_x, const int win_block_stride_y,
const float* block_hists, PtrStepf descriptors)
{
// Get left top corner of the window in src
const float* hist = block_hists + (blockIdx.y * win_block_stride_y * img_block_width +
blockIdx.x * win_block_stride_x) * cblock_hist_size;
// Get left top corner of the window in dst
float* descriptor = descriptors.ptr(blockIdx.y * gridDim.x + blockIdx.x);
// Copy elements from src to dst
for (int i = threadIdx.x; i < cdescr_size; i += nthreads)
{
int offset_y = i / cdescr_width;
int offset_x = i - offset_y * cdescr_width;
descriptor[i] = hist[offset_y * img_block_width * cblock_hist_size + offset_x];
}
}
void extract_descrs_by_rows(int win_height, int win_width, int block_stride_y, int block_stride_x, int win_stride_y, int win_stride_x,
int height, int width, float* block_hists, PtrStepSzf descriptors)
{
const int nthreads = 256;
int win_block_stride_x = win_stride_x / block_stride_x;
int win_block_stride_y = win_stride_y / block_stride_y;
int img_win_width = (width - win_width + win_stride_x) / win_stride_x;
int img_win_height = (height - win_height + win_stride_y) / win_stride_y;
dim3 threads(nthreads, 1);
dim3 grid(img_win_width, img_win_height);
int img_block_width = (width - CELLS_PER_BLOCK_X * CELL_WIDTH + block_stride_x) / block_stride_x;
extract_descrs_by_rows_kernel<nthreads><<<grid, threads>>>(
img_block_width, win_block_stride_x, win_block_stride_y, block_hists, descriptors);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
template <int nthreads>
__global__ void extract_descrs_by_cols_kernel(const int img_block_width, const int win_block_stride_x,
const int win_block_stride_y, const float* block_hists,
PtrStepf descriptors)
{
// Get left top corner of the window in src
const float* hist = block_hists + (blockIdx.y * win_block_stride_y * img_block_width +
blockIdx.x * win_block_stride_x) * cblock_hist_size;
// Get left top corner of the window in dst
float* descriptor = descriptors.ptr(blockIdx.y * gridDim.x + blockIdx.x);
// Copy elements from src to dst
for (int i = threadIdx.x; i < cdescr_size; i += nthreads)
{
int block_idx = i / cblock_hist_size;
int idx_in_block = i - block_idx * cblock_hist_size;
int y = block_idx / cnblocks_win_x;
int x = block_idx - y * cnblocks_win_x;
descriptor[(x * cnblocks_win_y + y) * cblock_hist_size + idx_in_block]
= hist[(y * img_block_width + x) * cblock_hist_size + idx_in_block];
}
}
void extract_descrs_by_cols(int win_height, int win_width, int block_stride_y, int block_stride_x,
int win_stride_y, int win_stride_x, int height, int width, float* block_hists,
PtrStepSzf descriptors)
{
const int nthreads = 256;
int win_block_stride_x = win_stride_x / block_stride_x;
int win_block_stride_y = win_stride_y / block_stride_y;
int img_win_width = (width - win_width + win_stride_x) / win_stride_x;
int img_win_height = (height - win_height + win_stride_y) / win_stride_y;
dim3 threads(nthreads, 1);
dim3 grid(img_win_width, img_win_height);
int img_block_width = (width - CELLS_PER_BLOCK_X * CELL_WIDTH + block_stride_x) / block_stride_x;
extract_descrs_by_cols_kernel<nthreads><<<grid, threads>>>(
img_block_width, win_block_stride_x, win_block_stride_y, block_hists, descriptors);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
//----------------------------------------------------------------------------
// Gradients computation
template <int nthreads, int correct_gamma>
__global__ void compute_gradients_8UC4_kernel(int height, int width, const PtrStepb img,
float angle_scale, PtrStepf grad, PtrStepb qangle)
{
const int x = blockIdx.x * blockDim.x + threadIdx.x;
const uchar4* row = (const uchar4*)img.ptr(blockIdx.y);
__shared__ float sh_row[(nthreads + 2) * 3];
uchar4 val;
if (x < width)
val = row[x];
else
val = row[width - 2];
sh_row[threadIdx.x + 1] = val.x;
sh_row[threadIdx.x + 1 + (nthreads + 2)] = val.y;
sh_row[threadIdx.x + 1 + 2 * (nthreads + 2)] = val.z;
if (threadIdx.x == 0)
{
val = row[::max(x - 1, 1)];
sh_row[0] = val.x;
sh_row[(nthreads + 2)] = val.y;
sh_row[2 * (nthreads + 2)] = val.z;
}
if (threadIdx.x == blockDim.x - 1)
{
val = row[::min(x + 1, width - 2)];
sh_row[blockDim.x + 1] = val.x;
sh_row[blockDim.x + 1 + (nthreads + 2)] = val.y;
sh_row[blockDim.x + 1 + 2 * (nthreads + 2)] = val.z;
}
__syncthreads();
if (x < width)
{
float3 a, b;
b.x = sh_row[threadIdx.x + 2];
b.y = sh_row[threadIdx.x + 2 + (nthreads + 2)];
b.z = sh_row[threadIdx.x + 2 + 2 * (nthreads + 2)];
a.x = sh_row[threadIdx.x];
a.y = sh_row[threadIdx.x + (nthreads + 2)];
a.z = sh_row[threadIdx.x + 2 * (nthreads + 2)];
float3 dx;
if (correct_gamma)
dx = make_float3(::sqrtf(b.x) - ::sqrtf(a.x), ::sqrtf(b.y) - ::sqrtf(a.y), ::sqrtf(b.z) - ::sqrtf(a.z));
else
dx = make_float3(b.x - a.x, b.y - a.y, b.z - a.z);
float3 dy = make_float3(0.f, 0.f, 0.f);
if (blockIdx.y > 0 && blockIdx.y < height - 1)
{
val = ((const uchar4*)img.ptr(blockIdx.y - 1))[x];
a = make_float3(val.x, val.y, val.z);
val = ((const uchar4*)img.ptr(blockIdx.y + 1))[x];
b = make_float3(val.x, val.y, val.z);
if (correct_gamma)
dy = make_float3(::sqrtf(b.x) - ::sqrtf(a.x), ::sqrtf(b.y) - ::sqrtf(a.y), ::sqrtf(b.z) - ::sqrtf(a.z));
else
dy = make_float3(b.x - a.x, b.y - a.y, b.z - a.z);
}
float best_dx = dx.x;
float best_dy = dy.x;
float mag0 = dx.x * dx.x + dy.x * dy.x;
float mag1 = dx.y * dx.y + dy.y * dy.y;
if (mag0 < mag1)
{
best_dx = dx.y;
best_dy = dy.y;
mag0 = mag1;
}
mag1 = dx.z * dx.z + dy.z * dy.z;
if (mag0 < mag1)
{
best_dx = dx.z;
best_dy = dy.z;
mag0 = mag1;
}
mag0 = ::sqrtf(mag0);
float ang = (::atan2f(best_dy, best_dx) + CV_PI_F) * angle_scale - 0.5f;
int hidx = (int)::floorf(ang);
ang -= hidx;
hidx = (hidx + cnbins) % cnbins;
((uchar2*)qangle.ptr(blockIdx.y))[x] = make_uchar2(hidx, (hidx + 1) % cnbins);
((float2*)grad.ptr(blockIdx.y))[x] = make_float2(mag0 * (1.f - ang), mag0 * ang);
}
}
void compute_gradients_8UC4(int nbins, int height, int width, const PtrStepSzb& img,
float angle_scale, PtrStepSzf grad, PtrStepSzb qangle, bool correct_gamma)
{
(void)nbins;
const int nthreads = 256;
dim3 bdim(nthreads, 1);
dim3 gdim(divUp(width, bdim.x), divUp(height, bdim.y));
if (correct_gamma)
compute_gradients_8UC4_kernel<nthreads, 1><<<gdim, bdim>>>(height, width, img, angle_scale, grad, qangle);
else
compute_gradients_8UC4_kernel<nthreads, 0><<<gdim, bdim>>>(height, width, img, angle_scale, grad, qangle);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
template <int nthreads, int correct_gamma>
__global__ void compute_gradients_8UC1_kernel(int height, int width, const PtrStepb img,
float angle_scale, PtrStepf grad, PtrStepb qangle)
{
const int x = blockIdx.x * blockDim.x + threadIdx.x;
const unsigned char* row = (const unsigned char*)img.ptr(blockIdx.y);
__shared__ float sh_row[nthreads + 2];
if (x < width)
sh_row[threadIdx.x + 1] = row[x];
else
sh_row[threadIdx.x + 1] = row[width - 2];
if (threadIdx.x == 0)
sh_row[0] = row[::max(x - 1, 1)];
if (threadIdx.x == blockDim.x - 1)
sh_row[blockDim.x + 1] = row[::min(x + 1, width - 2)];
__syncthreads();
if (x < width)
{
float dx;
if (correct_gamma)
dx = ::sqrtf(sh_row[threadIdx.x + 2]) - ::sqrtf(sh_row[threadIdx.x]);
else
dx = sh_row[threadIdx.x + 2] - sh_row[threadIdx.x];
float dy = 0.f;
if (blockIdx.y > 0 && blockIdx.y < height - 1)
{
float a = ((const unsigned char*)img.ptr(blockIdx.y + 1))[x];
float b = ((const unsigned char*)img.ptr(blockIdx.y - 1))[x];
if (correct_gamma)
dy = ::sqrtf(a) - ::sqrtf(b);
else
dy = a - b;
}
float mag = ::sqrtf(dx * dx + dy * dy);
float ang = (::atan2f(dy, dx) + CV_PI_F) * angle_scale - 0.5f;
int hidx = (int)::floorf(ang);
ang -= hidx;
hidx = (hidx + cnbins) % cnbins;
((uchar2*)qangle.ptr(blockIdx.y))[x] = make_uchar2(hidx, (hidx + 1) % cnbins);
((float2*) grad.ptr(blockIdx.y))[x] = make_float2(mag * (1.f - ang), mag * ang);
}
}
void compute_gradients_8UC1(int nbins, int height, int width, const PtrStepSzb& img,
float angle_scale, PtrStepSzf grad, PtrStepSzb qangle, bool correct_gamma)
{
(void)nbins;
const int nthreads = 256;
dim3 bdim(nthreads, 1);
dim3 gdim(divUp(width, bdim.x), divUp(height, bdim.y));
if (correct_gamma)
compute_gradients_8UC1_kernel<nthreads, 1><<<gdim, bdim>>>(height, width, img, angle_scale, grad, qangle);
else
compute_gradients_8UC1_kernel<nthreads, 0><<<gdim, bdim>>>(height, width, img, angle_scale, grad, qangle);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
}
//-------------------------------------------------------------------
// Resize
texture<uchar4, 2, cudaReadModeNormalizedFloat> resize8UC4_tex;
texture<uchar, 2, cudaReadModeNormalizedFloat> resize8UC1_tex;
__global__ void resize_for_hog_kernel(float sx, float sy, PtrStepSz<uchar> dst, int colOfs)
{
unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
if (x < dst.cols && y < dst.rows)
dst.ptr(y)[x] = tex2D(resize8UC1_tex, x * sx + colOfs, y * sy) * 255;
}
__global__ void resize_for_hog_kernel(float sx, float sy, PtrStepSz<uchar4> dst, int colOfs)
{
unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
if (x < dst.cols && y < dst.rows)
{
float4 val = tex2D(resize8UC4_tex, x * sx + colOfs, y * sy);
dst.ptr(y)[x] = make_uchar4(val.x * 255, val.y * 255, val.z * 255, val.w * 255);
}
}
template<class T, class TEX>
static void resize_for_hog(const PtrStepSzb& src, PtrStepSzb dst, TEX& tex)
{
tex.filterMode = cudaFilterModeLinear;
size_t texOfs = 0;
int colOfs = 0;
cudaChannelFormatDesc desc = cudaCreateChannelDesc<T>();
cudaSafeCall( cudaBindTexture2D(&texOfs, tex, src.data, desc, src.cols, src.rows, src.step) );
if (texOfs != 0)
{
colOfs = static_cast<int>( texOfs/sizeof(T) );
cudaSafeCall( cudaUnbindTexture(tex) );
cudaSafeCall( cudaBindTexture2D(&texOfs, tex, src.data, desc, src.cols, src.rows, src.step) );
}
dim3 threads(32, 8);
dim3 grid(divUp(dst.cols, threads.x), divUp(dst.rows, threads.y));
float sx = static_cast<float>(src.cols) / dst.cols;
float sy = static_cast<float>(src.rows) / dst.rows;
resize_for_hog_kernel<<<grid, threads>>>(sx, sy, (PtrStepSz<T>)dst, colOfs);
cudaSafeCall( cudaGetLastError() );
cudaSafeCall( cudaDeviceSynchronize() );
cudaSafeCall( cudaUnbindTexture(tex) );
}
void resize_8UC1(const PtrStepSzb& src, PtrStepSzb dst) { resize_for_hog<uchar> (src, dst, resize8UC1_tex); }
void resize_8UC4(const PtrStepSzb& src, PtrStepSzb dst) { resize_for_hog<uchar4>(src, dst, resize8UC4_tex); }
} // namespace hog
}}} // namespace cv { namespace cuda { namespace cudev
#endif /* CUDA_DISABLER */