ANSCORE/modules/ANSMOT/ByteTrack/src/STrack.cpp

#include "STrack.h"
#include <cstddef>

ByteTrack::STrack::STrack(const Rect<float>& rect,
                         const float& score,
                         int _class_id,
                         float _left,
                         float _top,
                         float _right,
                         float _bottom,
                         std::string _object_id) :
    kalman_filter_(),
    mean_(),
    covariance_(),
    rect_(rect),
    state_(STrackState::New),
    is_activated_(false),
    score_(score),
    track_id_(0),
    frame_id_(0),
    start_frame_id_(0),
    tracklet_len_(0),
    class_id(_class_id),
    left(_left),
    right(_right),
    top(_top),
    bottom(_bottom),
    object_id(_object_id)
{
    class_id_scores_[_class_id] = score;
    detection_count_ = 1;
    class_id_locked_ = false;
}

ByteTrack::STrack::~STrack()
{
}

void ByteTrack::STrack::voteClassId(int new_class_id, float score)
{
    if (class_id_locked_) return; // class_id is locked, no further changes

    class_id_scores_[new_class_id] += score;
    detection_count_++;

    // Pick the class_id with the highest accumulated score
    int best_id = class_id;
    float best_score = 0.0f;
    for (const auto& entry : class_id_scores_)
    {
        if (entry.second > best_score)
        {
            best_score = entry.second;
            best_id = entry.first;
        }
    }
    class_id = best_id;

    // Lock after enough detections
    if (detection_count_ >= CLASS_ID_LOCK_FRAMES)
    {
        class_id_locked_ = true;
    }
}

const ByteTrack::Rect<float>& ByteTrack::STrack::getRect() const
{
    return rect_;
}

const ByteTrack::STrackState& ByteTrack::STrack::getSTrackState() const
{
    return state_;
}

const bool& ByteTrack::STrack::isActivated() const
{
    return is_activated_;
}
const float& ByteTrack::STrack::getScore() const
{
    return score_;
}

const size_t& ByteTrack::STrack::getTrackId() const
{
    return track_id_;
}

const size_t& ByteTrack::STrack::getFrameId() const
{
    return frame_id_;
}

const size_t& ByteTrack::STrack::getStartFrameId() const
{
    return start_frame_id_;
}

const size_t& ByteTrack::STrack::getTrackletLength() const
{
    return tracklet_len_;
}

void ByteTrack::STrack::activate(const size_t& frame_id, const size_t& track_id)
{
    kalman_filter_.initiate(mean_, covariance_, rect_.getXyah());

    updateRect();

    state_ = STrackState::Tracked;
    if (frame_id == 1)
    {
        is_activated_ = true;
    }
    track_id_ = track_id;
    frame_id_ = frame_id;
    start_frame_id_ = frame_id;
    tracklet_len_ = 0;
}

void ByteTrack::STrack::reActivate(const STrack &new_track, const size_t &frame_id, const int &new_track_id)
{
    kalman_filter_.update(mean_, covariance_, new_track.getRect().getXyah());

    updateRect();

    state_ = STrackState::Tracked;
    is_activated_ = true;
    score_ = new_track.getScore();
    if (0 <= new_track_id)
    {
        track_id_ = new_track_id;
    }
    frame_id_ = frame_id;
    tracklet_len_ = 0;
    this->score_ = new_track.score_;
    voteClassId(new_track.class_id, new_track.score_); // score-weighted voting until locked
    this->left = new_track.left;
    this->top = new_track.top;
    this->right = new_track.right;
    this->bottom = new_track.bottom;
    this->object_id = new_track.object_id;
}

void ByteTrack::STrack::predict()
{
    if (state_ != STrackState::Tracked)
    {
        mean_[7] = 0; // zero height velocity only; keep x/y drift for moving objects
    }
    kalman_filter_.predict(mean_, covariance_);
}

void ByteTrack::STrack::update(const STrack &new_track, const size_t &frame_id)
{
    kalman_filter_.update(mean_, covariance_, new_track.getRect().getXyah());

    updateRect();

    state_ = STrackState::Tracked;
    is_activated_ = true;
    score_ = new_track.getScore();
    frame_id_ = frame_id;
    tracklet_len_++;
    this->score_ = new_track.score_;
    voteClassId(new_track.class_id, new_track.score_); // score-weighted voting until locked
    this->left = new_track.left;
    this->top = new_track.top;
    this->right = new_track.right;
    this->bottom = new_track.bottom;
    this->object_id = new_track.object_id;
}

void ByteTrack::STrack::markAsLost()
{
    state_ = STrackState::Lost;
}

void ByteTrack::STrack::markAsRemoved()
{
    state_ = STrackState::Removed;
}

void ByteTrack::STrack::updateRect()
{
    rect_.width() = mean_[2] * mean_[3];
    rect_.height() = mean_[3];
    rect_.x() = mean_[0] - rect_.width() / 2;
    rect_.y() = mean_[1] - rect_.height() / 2;
}