COMPMID-589: Port HOGDescriptor to new validation

Change-Id: I2021612e61de1b82aaeb49249d06929c7fceb15f
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/115216
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>

5 files changed, 625 insertions, 0 deletions

diff --git a/tests/validation/CL/HOGDescriptor.cpp b/tests/validation/CL/HOGDescriptor.cpp
new file mode 100644
index 0000000000..aef265a657
--- /dev/null
+++ b/tests/validation/CL/HOGDescriptor.cpp
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2017, 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 "arm_compute/runtime/CL/CLHOG.h"
+#include "arm_compute/runtime/CL/functions/CLHOGDescriptor.h"
+#include "arm_compute/runtime/Tensor.h"
+#include "arm_compute/runtime/TensorAllocator.h"
+#include "tests/CL/CLAccessor.h"
+#include "tests/PaddingCalculator.h"
+#include "tests/datasets/BorderModeDataset.h"
+#include "tests/datasets/HOGDescriptorDataset.h"
+#include "tests/datasets/ShapeDatasets.h"
+#include "tests/framework/Asserts.h"
+#include "tests/framework/Macros.h"
+#include "tests/framework/datasets/Datasets.h"
+#include "tests/validation/Validation.h"
+#include "tests/validation/fixtures/HOGDescriptorFixture.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace
+{
+AbsoluteTolerance<float> tolerance(1e-2f);
+} // namespace
+
+TEST_SUITE(CL)
+TEST_SUITE(HOGDescriptor)
+
+using CLHOGDescriptorFixture = HOGDescriptorValidationFixture<CLTensor, CLHOG, CLAccessor, CLHOGDescriptor, uint8_t, float>;
+
+// *INDENT-OFF*
+// clang-format off
+FIXTURE_DATA_TEST_CASE(RunSmall, CLHOGDescriptorFixture, framework::DatasetMode::PRECOMMIT,
+                       combine(combine(
+                       datasets::SmallHOGDescriptorDataset(),
+                       framework::dataset::make("Format", Format::U8)),
+                       framework::dataset::make("BorderMode", {BorderMode::CONSTANT, BorderMode::REPLICATE})))
+{
+    // Validate output
+    validate(CLAccessor(_target), _reference, tolerance);
+}
+
+FIXTURE_DATA_TEST_CASE(RunLarge, CLHOGDescriptorFixture, framework::DatasetMode::NIGHTLY,
+                       combine(combine(
+                       datasets::LargeHOGDescriptorDataset(),
+                       framework::dataset::make("Format", Format::U8)),
+                       framework::dataset::make("BorderMode", {BorderMode::CONSTANT, BorderMode::REPLICATE})))
+{
+    // Validate output
+    validate(CLAccessor(_target), _reference, tolerance);
+}
+// clang-format on
+// *INDENT-ON*
+
+TEST_SUITE_END()
+TEST_SUITE_END()
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/NEON/HOGDescriptor.cpp b/tests/validation/NEON/HOGDescriptor.cpp
new file mode 100644
index 0000000000..5f31773aad
--- /dev/null
+++ b/tests/validation/NEON/HOGDescriptor.cpp
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2017, 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 "arm_compute/runtime/HOG.h"
+#include "arm_compute/runtime/NEON/functions/NEHOGDescriptor.h"
+#include "arm_compute/runtime/Tensor.h"
+#include "arm_compute/runtime/TensorAllocator.h"
+#include "tests/NEON/Accessor.h"
+#include "tests/PaddingCalculator.h"
+#include "tests/datasets/BorderModeDataset.h"
+#include "tests/datasets/HOGDescriptorDataset.h"
+#include "tests/datasets/ShapeDatasets.h"
+#include "tests/framework/Asserts.h"
+#include "tests/framework/Macros.h"
+#include "tests/framework/datasets/Datasets.h"
+#include "tests/validation/Validation.h"
+#include "tests/validation/fixtures/HOGDescriptorFixture.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace
+{
+AbsoluteTolerance<float> tolerance(0.5f);
+constexpr float          tolerance_number = 0.01f;
+} // namespace
+
+TEST_SUITE(NEON)
+TEST_SUITE(HOGDescriptor)
+
+// *INDENT-OFF*
+// clang-format off
+using NEHOGDescriptorFixture = HOGDescriptorValidationFixture<Tensor, HOG, Accessor, NEHOGDescriptor, uint8_t, float>;
+
+FIXTURE_DATA_TEST_CASE(RunSmall, NEHOGDescriptorFixture, framework::DatasetMode::PRECOMMIT,
+                       combine(combine(
+                       datasets::SmallHOGDescriptorDataset(),
+                       framework::dataset::make("Format", Format::U8)),
+                       framework::dataset::make("BorderMode", {BorderMode::CONSTANT, BorderMode::REPLICATE})))
+{
+    // Validate output
+    validate(Accessor(_target), _reference, tolerance, tolerance_number);
+}
+
+FIXTURE_DATA_TEST_CASE(RunLarge, NEHOGDescriptorFixture, framework::DatasetMode::NIGHTLY,
+                       combine(combine(
+                       datasets::LargeHOGDescriptorDataset(),
+                       framework::dataset::make("Format", Format::U8)),
+                       framework::dataset::make("BorderMode", {BorderMode::CONSTANT, BorderMode::REPLICATE})))
+{
+    // Validate output
+    validate(Accessor(_target), _reference, tolerance, tolerance_number);
+}
+// clang-format on
+// *INDENT-ON*
+
+TEST_SUITE_END()
+TEST_SUITE_END()
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/fixtures/HOGDescriptorFixture.h b/tests/validation/fixtures/HOGDescriptorFixture.h
new file mode 100644
index 0000000000..cabee63ae3
--- /dev/null
+++ b/tests/validation/fixtures/HOGDescriptorFixture.h
@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+#ifndef ARM_COMPUTE_TEST_HOG_DESCRIPTOR_FIXTURE
+#define ARM_COMPUTE_TEST_HOG_DESCRIPTOR_FIXTURE
+
+#include "arm_compute/core/HOGInfo.h"
+#include "arm_compute/core/TensorShape.h"
+#include "arm_compute/core/Types.h"
+#include "tests/AssetsLibrary.h"
+#include "tests/Globals.h"
+#include "tests/IAccessor.h"
+#include "tests/framework/Asserts.h"
+#include "tests/framework/Fixture.h"
+#include "tests/validation/reference/HOGDescriptor.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+template <typename TensorType, typename HOGType, typename AccessorType, typename FunctionType, typename T, typename U>
+class HOGDescriptorValidationFixture : public framework::Fixture
+{
+public:
+    template <typename...>
+    void setup(std::string image, HOGInfo hog_info, Format format, BorderMode border_mode)
+    {
+        // Only defined borders supported
+        ARM_COMPUTE_ERROR_ON(border_mode == BorderMode::UNDEFINED);
+
+        // Generate a random constant value
+        std::mt19937                     gen(library->seed());
+        std::uniform_int_distribution<T> int_dist(0, 255);
+        const T                          constant_border_value = int_dist(gen);
+
+        _target    = compute_target(image, format, border_mode, constant_border_value, hog_info);
+        _reference = compute_reference(image, format, border_mode, constant_border_value, hog_info);
+    }
+
+protected:
+    template <typename V>
+    void fill(V &&tensor, const std::string image, Format format)
+    {
+        library->fill(tensor, image, format);
+    }
+
+    template <typename V, typename D>
+    void fill(V &&tensor, int i, D max)
+    {
+        library->fill_tensor_uniform(tensor, i, static_cast<D>(0), max);
+    }
+
+    TensorType compute_target(const std::string image, Format &format, BorderMode &border_mode, T constant_border_value, const HOGInfo &hog_info)
+    {
+        // Get image shape for src tensor
+        TensorShape shape = library->get_image_shape(image);
+
+        // Create tensor info for HOG descriptor
+        TensorInfo tensor_info_hog_descriptor(hog_info, shape.x(), shape.y());
+
+        // Create HOG
+        HOGType hog = create_HOG<HOGType>(hog_info.cell_size(),
+                                          hog_info.block_size(),
+                                          hog_info.detection_window_size(),
+                                          hog_info.block_stride(),
+                                          hog_info.num_bins(),
+                                          hog_info.normalization_type(),
+                                          hog_info.l2_hyst_threshold(),
+                                          hog_info.phase_type());
+
+        // Create tensors
+        TensorType src = create_tensor<TensorType>(shape, data_type_from_format(format));
+        TensorType dst = create_tensor<TensorType>(tensor_info_hog_descriptor.tensor_shape(), DataType::F32, tensor_info_hog_descriptor.num_channels());
+
+        ARM_COMPUTE_EXPECT(src.info()->is_resizable(), framework::LogLevel::ERRORS);
+        ARM_COMPUTE_EXPECT(dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+        // Create and configure function
+        FunctionType hog_descriptor;
+        hog_descriptor.configure(&src, &dst, &hog, border_mode, constant_border_value);
+
+        ARM_COMPUTE_EXPECT(src.info()->is_resizable(), framework::LogLevel::ERRORS);
+        ARM_COMPUTE_EXPECT(dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+        // Allocate tensors
+        src.allocator()->allocate();
+        dst.allocator()->allocate();
+        ARM_COMPUTE_EXPECT(!src.info()->is_resizable(), framework::LogLevel::ERRORS);
+        ARM_COMPUTE_EXPECT(!dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+        const T max = std::numeric_limits<T>::max();
+
+        // Fill tensors
+        fill(AccessorType(src), image, format);
+        fill(AccessorType(dst), 1, static_cast<U>(max));
+
+        // Compute function
+        hog_descriptor.run();
+
+        return dst;
+    }
+
+    SimpleTensor<U> compute_reference(const std::string image, Format format, BorderMode border_mode, T constant_border_value, const HOGInfo &hog_info)
+    {
+        // Create reference
+        SimpleTensor<T> src{ library->get_image_shape(image), data_type_from_format(format) };
+
+        // Fill reference
+        fill(src, image, format);
+
+        return reference::hog_descriptor<U>(src, border_mode, constant_border_value, hog_info);
+    }
+
+    TensorType      _target{};
+    SimpleTensor<U> _reference{};
+};
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif /* ARM_COMPUTE_TEST_HOG_DESCRIPTOR_FIXTURE */
diff --git a/tests/validation/reference/HOGDescriptor.cpp b/tests/validation/reference/HOGDescriptor.cpp
new file mode 100644
index 0000000000..369ac74edc
--- /dev/null
+++ b/tests/validation/reference/HOGDescriptor.cpp
@@ -0,0 +1,273 @@
+/*
+ * Copyright (c) 2017, 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 "HOGDescriptor.h"
+
+#include "Derivative.h"
+#include "Magnitude.h"
+#include "Phase.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+namespace
+{
+template <typename T>
+void hog_orientation_compute(const SimpleTensor<T> &mag, const SimpleTensor<T> &phase, std::vector<T> &bins, const HOGInfo &hog_info)
+{
+    const size_t num_bins    = hog_info.num_bins();
+    const size_t cell_height = hog_info.cell_size().height;
+    const size_t cell_width  = hog_info.cell_size().width;
+
+    float phase_scale = (PhaseType::SIGNED == hog_info.phase_type() ? num_bins / 360.0f : num_bins / 180.0f);
+    phase_scale *= (PhaseType::SIGNED == hog_info.phase_type() ? 360.0f / 255.0f : 1.0f);
+
+    int row_idx = 0;
+    for(size_t yc = 0; yc < cell_height; ++yc)
+    {
+        for(size_t xc = 0; xc < cell_height; xc++)
+        {
+            const float mag_value   = mag[(row_idx + xc)];
+            const float phase_value = phase[(row_idx + xc)] * phase_scale + 0.5f;
+            const float w1          = phase_value - floor(phase_value);
+
+            // The quantised phase is the histogram index [0, num_bins - 1]
+            // Check limit of histogram index. If hidx == num_bins, hidx = 0
+            const auto hidx = static_cast<unsigned int>(phase_value) % num_bins;
+
+            // Weighted vote between 2 bins
+            bins[hidx] += mag_value * (1.0f - w1);
+            bins[(hidx + 1) % num_bins] += mag_value * w1;
+        }
+
+        row_idx += cell_width;
+    }
+}
+
+template <typename T>
+void hog_block_normalization_compute(SimpleTensor<T> &block, SimpleTensor<T> &desc, const HOGInfo &hog_info, size_t block_idx)
+{
+    const int         num_bins_per_block = desc.num_channels();
+    const HOGNormType norm_type          = hog_info.normalization_type();
+    const Coordinates id                 = index2coord(desc.shape(), block_idx);
+
+    float sum = 0.0f;
+
+    // Calculate sum
+    for(int i = 0; i < num_bins_per_block; ++i)
+    {
+        const float val = block[i];
+        sum += (norm_type == HOGNormType::L1_NORM) ? std::fabs(val) : val * val;
+    }
+
+    // Calculate normalization scale
+    float scale = 1.0f / (std::sqrt(sum) + num_bins_per_block * 0.1f);
+
+    if(norm_type == HOGNormType::L2HYS_NORM)
+    {
+        // Reset sum
+        sum = 0.0f;
+        for(int i = 0; i < num_bins_per_block; ++i)
+        {
+            float val = block[i] * scale;
+
+            // Clip scaled input_value if over l2_hyst_threshold
+            val = fmin(val, hog_info.l2_hyst_threshold());
+            sum += val * val;
+            block[i] = val;
+        }
+
+        // We use the same constants of OpenCV
+        scale = 1.0f / (std::sqrt(sum) + 1e-3f);
+    }
+
+    for(int i = 0; i < num_bins_per_block; ++i)
+    {
+        block[i] *= scale;
+        reinterpret_cast<float *>(desc(id))[i] = block[i];
+    }
+}
+} // namespace
+
+template <typename T, typename U, typename V>
+void hog_orientation_binning(const SimpleTensor<T> &mag, const SimpleTensor<U> &phase, SimpleTensor<V> &hog_space, const HOGInfo &hog_info)
+{
+    const size_t cell_width   = hog_info.cell_size().width;
+    const size_t cell_height  = hog_info.cell_size().height;
+    const size_t shape_width  = hog_space.shape().x() * hog_info.cell_size().width;
+    const size_t shape_height = hog_space.shape().y() * hog_info.cell_size().height;
+
+    SimpleTensor<V> mag_cell(TensorShape(cell_width, cell_height), DataType::F32);
+    SimpleTensor<V> phase_cell(TensorShape(cell_width, cell_height), DataType::F32);
+
+    int cell_idx = 0;
+    int y_offset = 0;
+    int x_offset = 0;
+
+    // Traverse shape
+    for(auto sy = cell_height - 1; sy < shape_height; sy += cell_height)
+    {
+        x_offset = 0;
+        for(auto sx = cell_width - 1; sx < shape_width; sx += cell_width)
+        {
+            int row_idx  = 0;
+            int elem_idx = 0;
+
+            // Traverse cell
+            for(auto y = 0u; y < cell_height; ++y)
+            {
+                for(auto x = 0u; x < cell_width; ++x)
+                {
+                    int shape_idx        = x + row_idx + x_offset + y_offset;
+                    mag_cell[elem_idx]   = mag[shape_idx];
+                    phase_cell[elem_idx] = phase[shape_idx];
+                    elem_idx++;
+                }
+
+                row_idx += shape_width;
+            }
+
+            // Partition magnitude values into bins based on phase values
+            std::vector<V> bins(hog_info.num_bins());
+            hog_orientation_compute(mag_cell, phase_cell, bins, hog_info);
+
+            for(size_t i = 0; i < hog_info.num_bins(); ++i)
+            {
+                hog_space[cell_idx * hog_info.num_bins() + i] = bins[i];
+            }
+
+            x_offset += cell_width;
+            cell_idx++;
+        }
+
+        y_offset += (cell_height * shape_width);
+    }
+}
+
+template <typename T>
+void hog_block_normalization(SimpleTensor<T> &desc, const SimpleTensor<T> &hog_space, const HOGInfo &hog_info)
+{
+    const Size2D cells_per_block        = hog_info.num_cells_per_block();
+    const Size2D cells_per_block_stride = hog_info.num_cells_per_block_stride();
+
+    const size_t block_width         = hog_info.block_size().width;
+    const size_t block_height        = hog_info.block_size().height;
+    const size_t block_stride_width  = hog_info.block_stride().width;
+    const size_t block_stride_height = hog_info.block_stride().height;
+    const size_t shape_width         = hog_space.shape().x() * hog_info.cell_size().width;
+    const size_t shape_height        = hog_space.shape().y() * hog_info.cell_size().height;
+
+    const size_t num_bins     = hog_info.num_bins();
+    const size_t num_channels = cells_per_block.area() * num_bins;
+
+    SimpleTensor<T> block(TensorShape{ 1u, 1u }, DataType::F32, num_channels);
+
+    int block_idx      = 0;
+    int block_y_offset = 0;
+
+    // Traverse shape
+    for(auto sy = block_width - 1; sy < shape_height; sy += block_stride_height)
+    {
+        int block_x_offset = 0;
+        for(auto sx = block_height - 1; sx < shape_width; sx += block_stride_width)
+        {
+            int cell_y_offset = 0;
+            int elem_idx      = 0;
+
+            // Traverse block
+            for(auto y = 0u; y < cells_per_block.height; ++y)
+            {
+                int cell_x_offset = 0;
+                for(auto x = 0u; x < cells_per_block.width; ++x)
+                {
+                    for(auto bin = 0u; bin < num_bins; ++bin)
+                    {
+                        int idx         = bin + cell_x_offset + cell_y_offset + block_x_offset + block_y_offset;
+                        block[elem_idx] = hog_space[idx];
+                        elem_idx++;
+                    }
+
+                    cell_x_offset += num_bins;
+                }
+
+                cell_y_offset += hog_space.shape().x() * num_bins;
+            }
+
+            // Normalize block and write to descriptor
+            hog_block_normalization_compute(block, desc, hog_info, block_idx);
+
+            block_x_offset += cells_per_block_stride.width * num_bins;
+            block_idx++;
+        }
+
+        block_y_offset += cells_per_block_stride.height * num_bins * hog_space.shape().x();
+    }
+}
+
+template <typename T, typename U>
+SimpleTensor<T> hog_descriptor(const SimpleTensor<U> &src, BorderMode border_mode, U constant_border_value, const HOGInfo &hog_info)
+{
+    SimpleTensor<int16_t> _mag;
+    SimpleTensor<uint8_t> _phase;
+
+    SimpleTensor<int16_t> grad_x;
+    SimpleTensor<int16_t> grad_y;
+
+    // Create tensor info for HOG descriptor
+    TensorInfo      desc_info(hog_info, src.shape().x(), src.shape().y());
+    SimpleTensor<T> desc(desc_info.tensor_shape(), DataType::F32, desc_info.num_channels());
+
+    // Create HOG space tensor (num_cells_x, num_cells_y)
+    TensorShape hog_space_shape(src.shape().x() / hog_info.cell_size().width,
+                                src.shape().y() / hog_info.cell_size().height);
+
+    // For each cell a histogram with a num_bins is created
+    TensorInfo      info_hog_space(hog_space_shape, hog_info.num_bins(), DataType::F32);
+    SimpleTensor<T> hog_space(info_hog_space.tensor_shape(), DataType::F32, info_hog_space.num_channels());
+
+    // Calculate derivative
+    std::tie(grad_x, grad_y) = derivative<int16_t>(src, border_mode, constant_border_value, GradientDimension::GRAD_XY);
+
+    // Calculate magnitude and phase
+    _mag   = magnitude(grad_x, grad_y, MagnitudeType::L2NORM);
+    _phase = phase(grad_x, grad_y, hog_info.phase_type());
+
+    // For each cell create histogram based on magnitude and phase
+    hog_orientation_binning(_mag, _phase, hog_space, hog_info);
+
+    // Normalize histograms based on block size
+    hog_block_normalization(desc, hog_space, hog_info);
+
+    return desc;
+}
+
+template SimpleTensor<float> hog_descriptor(const SimpleTensor<uint8_t> &src, BorderMode border_mode, uint8_t constant_border_value, const HOGInfo &hog_info);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/reference/HOGDescriptor.h b/tests/validation/reference/HOGDescriptor.h
new file mode 100644
index 0000000000..e886445ec7
--- /dev/null
+++ b/tests/validation/reference/HOGDescriptor.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+#ifndef __ARM_COMPUTE_TEST_HOG_DESCRIPTOR_H__
+#define __ARM_COMPUTE_TEST_HOG_DESCRIPTOR_H__
+
+#include "tests/SimpleTensor.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T, typename U>
+SimpleTensor<T> hog_descriptor(const SimpleTensor<U> &src, BorderMode border_mode, U constant_border_value, const HOGInfo &hog_info);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_TEST_HOG_DESCRIPTOR_H__ */