source/application/api/use_case/object_detection/include/DetectorPostProcessing.hpp

/*
 * Copyright (c) 2022 Arm Limited. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef DETECTOR_POST_PROCESSING_HPP
#define DETECTOR_POST_PROCESSING_HPP

#include "ImageUtils.hpp"
#include "DetectionResult.hpp"
#include "YoloFastestModel.hpp"
#include "BaseProcessing.hpp"

#include <forward_list>

namespace arm {
namespace app {

namespace object_detection {

    struct Branch {
        int resolution;
        int numBox;
        const float* anchor;
        int8_t* modelOutput;
        float scale;
        int zeroPoint;
        size_t size;
    };

    struct Network {
        int inputWidth;
        int inputHeight;
        int numClasses;
        std::vector<Branch> branches;
        int topN;
    };

} /* namespace object_detection */

    /**
     * @brief   Post-processing class for Object Detection use case.
     *          Implements methods declared by BasePostProcess and anything else needed
     *          to populate result vector.
     */
    class DetectorPostProcess : public BasePostProcess {
    public:
        /**
         * @brief        Constructor.
         * @param[in]    outputTensor0   Pointer to the TFLite Micro output Tensor at index 0.
         * @param[in]    outputTensor1   Pointer to the TFLite Micro output Tensor at index 1.
         * @param[out]   results         Vector of detected results.
         * @param[in]    inputImgRows    Number of rows in the input image.
         * @param[in]    inputImgCols    Number of columns in the input image.
         * @param[in]    threshold       Post-processing threshold.
         * @param[in]    nms             Non-maximum Suppression threshold.
         * @param[in]    numClasses      Number of classes.
         * @param[in]    topN            Top N for each class.
         **/
        explicit DetectorPostProcess(TfLiteTensor* outputTensor0,
                                     TfLiteTensor* outputTensor1,
                                     std::vector<object_detection::DetectionResult>& results,
                                     int inputImgRows,
                                     int inputImgCols,
                                     float threshold = 0.5f,
                                     float nms = 0.45f,
                                     int numClasses = 1,
                                     int topN = 0);

        /**
         * @brief    Should perform YOLO post-processing of the result of inference then
         *           populate Detection result data for any later use.
         * @return   true if successful, false otherwise.
         **/
        bool DoPostProcess() override;

    private:
        TfLiteTensor* m_outputTensor0;     /* Output tensor index 0 */
        TfLiteTensor* m_outputTensor1;     /* Output tensor index 1 */
        std::vector<object_detection::DetectionResult>& m_results;  /* Single inference results. */
        int m_inputImgRows;                /* Number of rows for model input. */
        int m_inputImgCols;                /* Number of cols for model input. */
        float m_threshold;                 /* Post-processing threshold. */
        float m_nms;                       /* NMS threshold. */
        int   m_numClasses;                /* Number of classes. */
        int   m_topN;                      /* TopN. */
        object_detection::Network m_net;   /* YOLO network object. */

        /**
         * @brief       Insert the given Detection in the list.
         * @param[in]   detections   List of detections.
         * @param[in]   det          Detection to be inserted.
         **/
        void InsertTopNDetections(std::forward_list<image::Detection>& detections, image::Detection& det);

        /**
         * @brief        Given a Network calculate the detection boxes.
         * @param[in]    net           Network.
         * @param[in]    imageWidth    Original image width.
         * @param[in]    imageHeight   Original image height.
         * @param[in]    threshold     Detections threshold.
         * @param[out]   detections    Detection boxes.
         **/
        void GetNetworkBoxes(object_detection::Network& net,
                             int imageWidth,
                             int imageHeight,
                             float threshold,
                             std::forward_list<image::Detection>& detections);
    };

} /* namespace app */
} /* namespace arm */

#endif /* DETECTOR_POST_PROCESSING_HPP */