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/*
* Copyright (c) 2018-2019 Arm Limited.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "HOGDetector.h"
namespace arm_compute
{
namespace test
{
namespace validation
{
namespace reference
{
namespace
{
/** Computes the number of detection windows to iterate over in the feature vector. */
Size2D num_detection_windows(const TensorShape &shape, const Size2D &window_step, const HOGInfo &hog_info)
{
const size_t num_block_strides_width = hog_info.detection_window_size().width / hog_info.block_stride().width;
const size_t num_block_strides_height = hog_info.detection_window_size().height / hog_info.block_stride().height;
return Size2D{ floor_to_multiple(shape.x() - num_block_strides_width, window_step.width) + window_step.width,
floor_to_multiple(shape.y() - num_block_strides_height, window_step.height) + window_step.height };
}
} // namespace
template <typename T>
std::vector<DetectionWindow> hog_detector(const SimpleTensor<T> &src, const std::vector<T> &descriptor, unsigned int max_num_detection_windows,
const HOGInfo &hog_info, const Size2D &detection_window_stride, float threshold, uint16_t idx_class)
{
ARM_COMPUTE_ERROR_ON_MSG((detection_window_stride.width % hog_info.block_stride().width != 0),
"Detection window stride width must be multiple of block stride width");
ARM_COMPUTE_ERROR_ON_MSG((detection_window_stride.height % hog_info.block_stride().height != 0),
"Detection window stride height must be multiple of block stride height");
// Create vector for identifying each detection window
std::vector<DetectionWindow> windows;
// Calculate detection window step
const Size2D window_step(detection_window_stride.width / hog_info.block_stride().width,
detection_window_stride.height / hog_info.block_stride().height);
// Calculate number of detection windows
const Size2D num_windows = num_detection_windows(src.shape(), window_step, hog_info);
// Calculate detection window and row offsets in feature vector
const size_t src_offset_x = window_step.width * hog_info.num_bins() * hog_info.num_cells_per_block().area();
const size_t src_offset_y = window_step.height * hog_info.num_bins() * hog_info.num_cells_per_block().area() * src.shape().x();
const size_t src_offset_row = src.num_channels() * src.shape().x();
// Calculate detection window attributes
const Size2D num_block_positions_per_detection_window = hog_info.num_block_positions_per_image(hog_info.detection_window_size());
const unsigned int num_bins_per_descriptor_x = num_block_positions_per_detection_window.width * src.num_channels();
const unsigned int num_blocks_per_descriptor_y = num_block_positions_per_detection_window.height;
ARM_COMPUTE_ERROR_ON((num_bins_per_descriptor_x * num_blocks_per_descriptor_y + 1) != hog_info.descriptor_size());
size_t win_id = 0;
// Traverse feature vector in detection window steps
for(auto win_y = 0u, offset_y = 0u; win_y < num_windows.height; win_y += window_step.height, offset_y += src_offset_y)
{
for(auto win_x = 0u, offset_x = 0u; win_x < num_windows.width; win_x += window_step.width, offset_x += src_offset_x)
{
// Reset the score
float score = 0.0f;
// Traverse detection window
for(auto y = 0u, offset_row = 0u; y < num_blocks_per_descriptor_y; ++y, offset_row += src_offset_row)
{
const int bin_offset = y * num_bins_per_descriptor_x;
for(auto x = 0u; x < num_bins_per_descriptor_x; ++x)
{
// Compute Linear SVM
const float a = src[x + offset_x + offset_y + offset_row];
const float b = descriptor[x + bin_offset];
score += a * b;
}
}
// Add the bias. The bias is located at the position (descriptor_size() - 1)
score += descriptor[num_bins_per_descriptor_x * num_blocks_per_descriptor_y];
if(score > threshold)
{
DetectionWindow window;
if(win_id++ < max_num_detection_windows)
{
window.x = win_x * hog_info.block_stride().width;
window.y = win_y * hog_info.block_stride().height;
window.width = hog_info.detection_window_size().width;
window.height = hog_info.detection_window_size().height;
window.idx_class = idx_class;
window.score = score;
windows.push_back(window);
}
}
}
}
return windows;
}
template std::vector<DetectionWindow> hog_detector(const SimpleTensor<float> &src, const std::vector<float> &descriptor, unsigned int max_num_detection_windows,
const HOGInfo &hog_info, const Size2D &detection_window_stride, float threshold, uint16_t idx_class);
} // namespace reference
} // namespace validation
} // namespace test
} // namespace arm_compute
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