Knowledge Base

Problem

Captured footprint images are unclear, partially cut off at the front or back of the walkway, or contaminated by light reflection from the animal's abdominal fur or body hair, preventing accurate measurement.

Details

Two related but distinct causes: (1) Detection settings (run detection thresholds, corridor length settings) are not tuned, causing the acquisition window to cut off early or late, clipping prints at the edges. (2) The illumination track has come loose from the CatWalk walkway chassis, causing uneven or scattered green light emission that reflects off body fur rather than being confined to paw contacts on the glass. Affects all animal sizes; particularly problematic with long-haired or obese animals.

Solution

**For footprints cut off (clipping at front/back):**
1. Open Detection Settings in CatWalk XT and review the run detection parameters, including minimum/maximum run duration and the walkway area boundaries.
2. Adjust the detection zone to ensure the full walkway length is captured and the acquisition window does not terminate prematurely.
3. Runs already collected with clipping will need to be manually labeled for the affected prints; adjust settings before repeating acquisitions.

**For body hair reflection contaminating the image:**
1. Physically inspect the CatWalk walkway to check whether the internal illumination track is fully and evenly seated in its channel.
2. If the track is loose or misaligned, carefully reseat it per the hardware installation guide or contact Noldus support.
3. After reinstalling the track, readjust the Green Intensity Threshold in Detection Settings to account for the now-uniform light emission.
4. If body hair reflection persists despite correct track installation, consider trimming abdominal fur minimally if the experimental protocol allows, and raise the intensity threshold slightly to reduce false detections from fur.