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Declare tracking lost when the marker leaves the frame (#46) #47

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Merged
kalwalt merged 1 commit into from
Jun 15, 2026
Merged

Declare tracking lost when the marker leaves the frame (#46) #47

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18 changes: 17 additions & 1 deletion WebARKit/WebARKitTrackers/WebARKitOpticalTracking/WebARKitTracker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -297,6 +297,14 @@ class WebARKitTracker::WebARKitTrackerImpl {
// _trackables[trackableId]._isDetected = false;
_isTracking = false;
_isDetected = false;
// WebARKitLib#46: template matching is the appearance check -- if it fails
// (the tracked region no longer looks like the marker, e.g. the marker
// left the frame and optical flow drifted onto static background), the
// marker is lost. Clear _valid too so isValid() turns false and the
// tracker reports 'not found'. runOpticalFlow's failure path already does
// this; ArtoolkitX has no _valid and treats !isDetected && !isTracking as
// "not visible" (IsTrackableVisible).
this->_valid = false;
_currentlyTrackedMarkers--;
}
if (_trackVizActive) {
Expand Down Expand Up @@ -344,7 +352,15 @@ class WebARKitTracker::WebARKitTrackerImpl {
MatchFeatures(frameKeyPts, frameDescr);
}
int i = 0;
if (_isDetected) {
// WebARKitLib#46: also run optical flow while tracking, not only on a fresh
// detection. When the marker leaves the frame, MatchFeatures fails
// (_isDetected = false) but _isTracking is still true; running optical flow
// here lets it fail on the now-absent marker and clear _isTracking/_valid
// (via updateTrackableHomography), so isValid() turns false and the tracker
// reports 'not found' instead of staying stuck on a stale pose. It also
// bridges momentary detection dropouts with a fresh pose while the marker is
// still present.
if (_isDetected || _isTracking) {
WEBARKIT_LOGd("Start tracking!\n");
if (_frameCount > 0 && _prevPyramid.size() > 0) {
// if (_prevPyramid.size() > 0) {
Expand Down