arm_compute v18.05
diff --git a/tests/validation/reference/HOGDetector.cpp b/tests/validation/reference/HOGDetector.cpp
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+/*
+ * Copyright (c) 2018 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