Knowledge Base

Problem

A specific animal or trial shows detection rates below 80%, particularly when the animal moves near or interacts with an object placed inside the arena (e.g., a black cup, dark object, or enrichment item). The tracking line turns gray (indicating lost detection) near the object. Re-grabbing the background and re-tracking do not resolve the issue.

Details

Symptom: Detection rate below 80% for specific animals or arena regions. Tracking is lost when the animal is near or under a dark object in the arena. Gray tracking line segments indicate missed samples near the object. Affected: Any EthoVision XT version with contrast-based (non-deep-learning) detection. Common in: Object recognition, enriched environments, or any setup with in-arena items that closely match the animal's color.

Solution

1. Check arena lighting: ensure illumination is even and diffuse across the entire arena, including around and under any in-arena objects. Use additional light sources or reposition existing ones to eliminate shadows cast by the object.
2. Use matte, mid-gray arena walls and floor materials to maximize contrast between the animal and the background. Avoid highly reflective surfaces.
3. In Detection Settings, review and adjust the detection threshold for the animal's color relative to the background. Try slightly increasing or decreasing the threshold to see if detection improves near the problematic object.
4. If the object is static and always in the same position, use the 'Doughnut cutout' or exclusion zone drawing method in Arena Settings to exclude the object's footprint from the detection area, preventing the object from interfering with detection.
5. Consider switching to 3-point (nose, body center, tail base) tracking if using center-point only; multi-point tracking can be more robust when parts of the animal are briefly occluded.
6. If the object is meant to be interacted with (e.g., a novel object), ensure the object itself is a color that contrasts with the animal (e.g., use a white object for a dark animal).
7. As a last resort for intractable cases, manually correct affected frames in the Track Editor using interpolation.