Variants
Precision tracking with an IR spot
When you need to follow a single spot very precisely.
Some studies need to follow a small marked point on the animal rather than its whole body. These questions cover the camera, the lighting and the infrared marker.
Questions people ask
How do I set up the camera and lighting for the Precision Tracker?
The Precision Tracker needs its infrared camera to see only the glowing marker, so you light the arena with the red flood light and keep other infrared light out. Shine the red flood light onto the arena from close by, and remove other infrared sources. 1) Position the IR camera so the arena fills the image. 2) Use daylight or a normal bulb only to see the arena during set-up. 3) For trials, test your room lights: a dull image is fine, a bright one is not.
More detail
The Precision Tracker tracks a phosphor marker that glows in infrared under red light, so camera and lighting set-up is about making that marker the only bright thing in the infrared image. The Precision Tracker kit comprises an infrared LabCam with a 715 nm cut-off, a 615 nm red flood light, down-converter phosphor powder and an animal-safe waterproof adhesive. Shine the flood light directly onto the tracking area from as close as practical; it makes the marker emit infrared that appears bright white in the video. To see the arena during set-up you need a light containing infrared (daylight or an incandescent bulb). Fit the camera so the area fills the image and plug it into a (preferably blue) USB port. The focus is preset for your described set-up. During experiments eliminate infrared sources; a dull image is acceptable, a bright one needs a different light source.
Going deeper
The Precision Tracker tracks a precise spot (usually on the head) with any coat colour, background or objects, and in the dark. It suits NOR head tracking in small arenas and mixed-colour cohorts, and avoids the head/tail swaps of body-shape trackers.
How do I mark the animal and track the IR spot with the Precision Tracker?
Mix a little phosphor with half a drop of adhesive, put a 2 mm spot on the head, then track with the background set to black. 1) Avoid the eye area. 2) Start with a small (not zero) size threshold. 3) Move the threshold until a red cross follows the spot. 4) Raise the size threshold to ignore smaller specks.
More detail
Take a small amount of phosphor powder with the spatula, add half a drop of Liquid Skin and mix thoroughly; this marks several animals. Put a spot on the area to track, such as the top of the head, avoiding the eyes; 2 mm is enough when the camera is about 50 cm away. Wash your hands afterwards. Then follow the calibration instructions for your experiment, setting the background as black, starting with a small (non-zero) size threshold, moving the general threshold until a red cross tracks the white spot, and raising the size threshold to ignore smaller specks.
Going deeper
Use both IR lights where supplied and keep the marker small for precision. Follow the safety data sheet supplied with the phosphor powder when handling it, and wash your hands after use.
The product page is HVS Image Precision Tracker.
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