COMPMID-1463: SSD support: Create Detection layer

Change-Id: I8b59b9b94cbd132e1ff5157a4c59882719e12e3b
Reviewed-on: https://review.mlplatform.org/327
Reviewed-by: Anthony Barbier <Anthony.barbier@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>

3 files changed, 229 insertions, 0 deletions

diff --git a/arm_compute/core/Types.h b/arm_compute/core/Types.h
index 6833a66cd9..75b38c5cb8 100644
--- a/arm_compute/core/Types.h
+++ b/arm_compute/core/Types.h
@@ -995,6 +995,134 @@ private:
     std::array<float, 2> _steps;
 };
 
+/** Available Detection Output code types */
+enum class DetectionOutputLayerCodeType
+{
+    CORNER,      /**< Use box corners */
+    CENTER_SIZE, /**< Use box centers and size */
+    CORNER_SIZE, /**< Use box centers and size */
+    TF_CENTER    /**< Use box centers and size but flip x and y co-ordinates */
+};
+
+/** Detection Output layer info */
+class DetectionOutputLayerInfo final
+{
+public:
+    /** Default Constructor */
+    DetectionOutputLayerInfo()
+        : _num_classes(),
+          _share_location(),
+          _code_type(DetectionOutputLayerCodeType::CORNER),
+          _keep_top_k(),
+          _nms_threshold(),
+          _top_k(),
+          _background_label_id(),
+          _confidence_threshold(),
+          _variance_encoded_in_target(false),
+          _eta(),
+          _num_loc_classes()
+    {
+        _num_loc_classes = _share_location ? 1 : _num_classes;
+    }
+    /** Constructor
+     *
+     * @param[in] num_classes                Number of classes to be predicted.
+     * @param[in] share_location             If true, bounding box are shared among different classes.
+     * @param[in] code_type                  Type of coding method for bbox.
+     * @param[in] keep_top_k                 Number of total bounding boxes to be kept per image after NMS step.
+     * @param[in] nms_threshold              Threshold to be used in NMS.
+     * @param[in] top_k                      (Optional) Number of boxes per image with top confidence scores that are fed into the NMS algorithm. Default set to -1.
+     * @param[in] background_label_id        (Optional) Background label ID. If there is no background class, set it as -1.
+     * @param[in] confidence_threshold       (Optional) Only consider detections whose confidences are larger than a threshold. Default set to -FLT_MAX.
+     * @param[in] variance_encoded_in_target (Optional) If true, variance is encoded in target. Otherwise we need to adjust the predicted offset accordingly.Default set to false.
+     * @param[in] eta                        (Optional) Eta.
+     */
+    DetectionOutputLayerInfo(int num_classes, bool share_location, DetectionOutputLayerCodeType code_type, int keep_top_k, float nms_threshold, int top_k = -1, int background_label_id = -1,
+                             float confidence_threshold = std::numeric_limits<float>::lowest(), bool variance_encoded_in_target = false, float eta = 1)
+        : _num_classes(num_classes),
+          _share_location(share_location),
+          _code_type(code_type),
+          _keep_top_k(keep_top_k),
+          _nms_threshold(nms_threshold),
+          _top_k(top_k),
+          _background_label_id(background_label_id),
+          _confidence_threshold(confidence_threshold),
+          _variance_encoded_in_target(variance_encoded_in_target),
+          _eta(eta),
+          _num_loc_classes()
+    {
+        _num_loc_classes = _share_location ? 1 : _num_classes;
+    }
+    /** Get num classes. */
+    int num_classes() const
+    {
+        return _num_classes;
+    }
+    /** Get share location. */
+    bool share_location() const
+    {
+        return _share_location;
+    }
+    /** Get detection output code type. */
+    DetectionOutputLayerCodeType code_type() const
+    {
+        return _code_type;
+    }
+    /** Get if variance encoded in target. */
+    bool variance_encoded_in_target() const
+    {
+        return _variance_encoded_in_target;
+    }
+    /** Get the number of total bounding boxes to be kept per image. */
+    int keep_top_k() const
+    {
+        return _keep_top_k;
+    }
+    /** Get nms threshold. */
+    float nms_threshold() const
+    {
+        return _nms_threshold;
+    }
+    /** Get eta. */
+    float eta() const
+    {
+        return _eta;
+    }
+    /** Get background label ID. */
+    int background_label_id() const
+    {
+        return _background_label_id;
+    }
+    /** Get confidence threshold. */
+    float confidence_threshold() const
+    {
+        return _confidence_threshold;
+    }
+    /** Get top K. */
+    int top_k() const
+    {
+        return _top_k;
+    }
+    /** Get number of location classes. */
+    int num_loc_classes() const
+    {
+        return _num_loc_classes;
+    }
+
+private:
+    int                          _num_classes;
+    bool                         _share_location;
+    DetectionOutputLayerCodeType _code_type;
+    int                          _keep_top_k;
+    float                        _nms_threshold;
+    int                          _top_k;
+    int                          _background_label_id;
+    float                        _confidence_threshold;
+    bool                         _variance_encoded_in_target;
+    float                        _eta;
+    int                          _num_loc_classes;
+};
+
 /** Pooling Layer Information class */
 class PoolingLayerInfo
 {
diff --git a/arm_compute/runtime/CPP/CPPFunctions.h b/arm_compute/runtime/CPP/CPPFunctions.h
index 9c17d9e404..63df437d11 100644
--- a/arm_compute/runtime/CPP/CPPFunctions.h
+++ b/arm_compute/runtime/CPP/CPPFunctions.h
@@ -26,6 +26,7 @@
 
 /* Header regrouping all the CPP functions */
 #include "arm_compute/runtime/CPP/functions/CPPBoxWithNonMaximaSuppressionLimit.h"
+#include "arm_compute/runtime/CPP/functions/CPPDetectionOutputLayer.h"
 #include "arm_compute/runtime/CPP/functions/CPPPermute.h"
 #include "arm_compute/runtime/CPP/functions/CPPUpsample.h"
 
diff --git a/arm_compute/runtime/CPP/functions/CPPDetectionOutputLayer.h b/arm_compute/runtime/CPP/functions/CPPDetectionOutputLayer.h
new file mode 100644
index 0000000000..7f80948c81
--- /dev/null
+++ b/arm_compute/runtime/CPP/functions/CPPDetectionOutputLayer.h
@@ -0,0 +1,100 @@
+/*
+ * 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.
+ */
+#ifndef __ARM_COMPUTE_CPP_DETECTION_OUTPUT_LAYER_H__
+#define __ARM_COMPUTE_CPP_DETECTION_OUTPUT_LAYER_H__
+
+#include "arm_compute/runtime/CPP/ICPPSimpleFunction.h"
+
+#include "arm_compute/core/Types.h"
+
+#include <map>
+
+namespace arm_compute
+{
+class ITensor;
+
+// Normalized Bounding Box [xmin, ymin, xmax, ymax]
+using NormalizedBBox = std::array<float, 4>;
+// LabelBBox used for map label and bounding box
+using LabelBBox = std::map<int, std::vector<NormalizedBBox>>;
+
+/** CPP Function to generate the detection output based on location and confidence
+ * predictions by doing non maximum suppression.
+ *
+ * @note Intended for use with MultiBox detection method.
+ */
+class CPPDetectionOutputLayer : public IFunction
+{
+public:
+    /** Default constructor */
+    CPPDetectionOutputLayer();
+    /** Configure the detection output layer CPP kernel
+     *
+     * @param[in]  input_loc      The mbox location input tensor of size [C1, N]. Data types supported: F32.
+     * @param[in]  input_conf     The mbox confidence input tensor of size [C2, N]. Data types supported: F32.
+     * @param[in]  input_priorbox The mbox prior box input tensor of size [C3, 2, N]. Data types supported: F32.
+     * @param[out] output         The output tensor of size [7, M]. Data types supported: Same as @p input
+     * @param[in]  info           (Optional) DetectionOutputLayerInfo information.
+     *
+     * @note Output contains all the detections. Of those, only the ones selected by the valid region are valid.
+     */
+    void configure(const ITensor *input_loc, const ITensor *input_conf, const ITensor *input_priorbox, ITensor *output, DetectionOutputLayerInfo info = DetectionOutputLayerInfo());
+    /** Static function to check if given info will lead to a valid configuration of @ref CPPDetectionOutputLayer
+     *
+     * @param[in] input_loc      The mbox location input tensor info. Data types supported: F32.
+     * @param[in] input_conf     The mbox confidence input tensor info. Data types supported: F32.
+     * @param[in] input_priorbox The mbox prior box input tensor info. Data types supported: F32.
+     * @param[in] output         The output tensor info. Data types supported: Same as @p input
+     * @param[in] info           (Optional) DetectionOutputLayerInfo information.
+     *
+     * @return a status
+     */
+    static Status validate(const ITensorInfo *input_loc, const ITensorInfo *input_conf, const ITensorInfo *input_priorbox, const ITensorInfo *output,
+                           DetectionOutputLayerInfo info = DetectionOutputLayerInfo());
+    // Inherited methods overridden:
+    void run() override;
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    CPPDetectionOutputLayer(const CPPDetectionOutputLayer &) = delete;
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    CPPDetectionOutputLayer &operator=(const CPPDetectionOutputLayer &) = delete;
+
+private:
+    const ITensor           *_input_loc;
+    const ITensor           *_input_conf;
+    const ITensor           *_input_priorbox;
+    ITensor                 *_output;
+    DetectionOutputLayerInfo _info;
+
+    int _num_priors;
+    int _num;
+
+    std::vector<LabelBBox> _all_location_predictions;
+    std::vector<std::map<int, std::vector<float>>> _all_confidence_scores;
+    std::vector<NormalizedBBox> _all_prior_bboxes;
+    std::vector<std::array<float, 4>> _all_prior_variances;
+    std::vector<LabelBBox> _all_decode_bboxes;
+    std::vector<std::map<int, std::vector<int>>> _all_indices;
+};
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_CPP_DETECTION_OUTPUT_LAYER_H__ */