cuda-samples/Samples/HSOpticalFlow/derivativesKernel.cuh

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2021-10-21 19:04:49 +08:00
/* Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of NVIDIA CORPORATION nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "common.h"
///////////////////////////////////////////////////////////////////////////////
/// \brief compute image derivatives
///
/// CUDA kernel, relies heavily on texture unit
/// \param[in] width image width
/// \param[in] height image height
/// \param[in] stride image stride
/// \param[out] Ix x derivative
/// \param[out] Iy y derivative
/// \param[out] Iz temporal derivative
///////////////////////////////////////////////////////////////////////////////
__global__ void ComputeDerivativesKernel(int width, int height, int stride,
float *Ix, float *Iy, float *Iz,
cudaTextureObject_t texSource,
cudaTextureObject_t texTarget) {
const int ix = threadIdx.x + blockIdx.x * blockDim.x;
const int iy = threadIdx.y + blockIdx.y * blockDim.y;
const int pos = ix + iy * stride;
if (ix >= width || iy >= height) return;
float dx = 1.0f / (float)width;
float dy = 1.0f / (float)height;
float x = ((float)ix + 0.5f) * dx;
float y = ((float)iy + 0.5f) * dy;
float t0, t1;
// x derivative
t0 = tex2D<float>(texSource, x - 2.0f * dx, y);
t0 -= tex2D<float>(texSource, x - 1.0f * dx, y) * 8.0f;
t0 += tex2D<float>(texSource, x + 1.0f * dx, y) * 8.0f;
t0 -= tex2D<float>(texSource, x + 2.0f * dx, y);
t0 /= 12.0f;
t1 = tex2D<float>(texTarget, x - 2.0f * dx, y);
t1 -= tex2D<float>(texTarget, x - 1.0f * dx, y) * 8.0f;
t1 += tex2D<float>(texTarget, x + 1.0f * dx, y) * 8.0f;
t1 -= tex2D<float>(texTarget, x + 2.0f * dx, y);
t1 /= 12.0f;
Ix[pos] = (t0 + t1) * 0.5f;
// t derivative
Iz[pos] = tex2D<float>(texTarget, x, y) - tex2D<float>(texSource, x, y);
// y derivative
t0 = tex2D<float>(texSource, x, y - 2.0f * dy);
t0 -= tex2D<float>(texSource, x, y - 1.0f * dy) * 8.0f;
t0 += tex2D<float>(texSource, x, y + 1.0f * dy) * 8.0f;
t0 -= tex2D<float>(texSource, x, y + 2.0f * dy);
t0 /= 12.0f;
t1 = tex2D<float>(texTarget, x, y - 2.0f * dy);
t1 -= tex2D<float>(texTarget, x, y - 1.0f * dy) * 8.0f;
t1 += tex2D<float>(texTarget, x, y + 1.0f * dy) * 8.0f;
t1 -= tex2D<float>(texTarget, x, y + 2.0f * dy);
t1 /= 12.0f;
Iy[pos] = (t0 + t1) * 0.5f;
}
///////////////////////////////////////////////////////////////////////////////
/// \brief compute image derivatives
///
/// \param[in] I0 source image
/// \param[in] I1 tracked image
/// \param[in] w image width
/// \param[in] h image height
/// \param[in] s image stride
/// \param[out] Ix x derivative
/// \param[out] Iy y derivative
/// \param[out] Iz temporal derivative
///////////////////////////////////////////////////////////////////////////////
static void ComputeDerivatives(const float *I0, const float *I1, int w, int h,
int s, float *Ix, float *Iy, float *Iz) {
dim3 threads(32, 6);
dim3 blocks(iDivUp(w, threads.x), iDivUp(h, threads.y));
cudaTextureObject_t texSource, texTarget;
cudaResourceDesc texRes;
memset(&texRes, 0, sizeof(cudaResourceDesc));
texRes.resType = cudaResourceTypePitch2D;
texRes.res.pitch2D.devPtr = (void *)I0;
texRes.res.pitch2D.desc = cudaCreateChannelDesc<float>();
texRes.res.pitch2D.width = w;
texRes.res.pitch2D.height = h;
texRes.res.pitch2D.pitchInBytes = s * sizeof(float);
cudaTextureDesc texDescr;
memset(&texDescr, 0, sizeof(cudaTextureDesc));
texDescr.normalizedCoords = true;
texDescr.filterMode = cudaFilterModeLinear;
texDescr.addressMode[0] = cudaAddressModeMirror;
texDescr.addressMode[1] = cudaAddressModeMirror;
texDescr.readMode = cudaReadModeElementType;
checkCudaErrors(
cudaCreateTextureObject(&texSource, &texRes, &texDescr, NULL));
memset(&texRes, 0, sizeof(cudaResourceDesc));
texRes.resType = cudaResourceTypePitch2D;
texRes.res.pitch2D.devPtr = (void *)I1;
texRes.res.pitch2D.desc = cudaCreateChannelDesc<float>();
texRes.res.pitch2D.width = w;
texRes.res.pitch2D.height = h;
texRes.res.pitch2D.pitchInBytes = s * sizeof(float);
checkCudaErrors(
cudaCreateTextureObject(&texTarget, &texRes, &texDescr, NULL));
ComputeDerivativesKernel<<<blocks, threads>>>(w, h, s, Ix, Iy, Iz, texSource,
texTarget);
}