# Subject exposure

Aim

To obtain a balanced image of the subject. This is of critical importance when using Behavior recognition.

Prerequisites

▪Your experiment is set for Behavior recognition.

▪You open the Detection Settings.

Procedure

1.Play the video or let the subject walk in the arena.

2.In the Detection Performance window, locate the Subject Exposure indicator.

3.Make sure that the Exposure is Good when the subjects has been in all parts of the arena.

4.When the image is overexposed or underexposed, the subject looks too bright or too dark, respectively. The details of the fur are hardly visible. Try the following:

To reduce the subject’s exposure, close the aperture of the camera lens. Alternatively, for GigE and USB cameras, reduce the Exposure time.

To increase the subject’s exposure, open the aperture of the camera lens or increase the Exposure time. If that is not possible, increase the Gain.

For how to adjust the exposure and gain, see Adjust camera settings in EthoVision XT.

Notes

Check the exposure level when the subject is walking, or sitting still. The subject’s tail should not touch the sides of its body. It that occurs, the estimate of subject exposure may not be reliable.

In the following example, the image of the rat is clearly overexposed (left). However when the tip of the rat’s tail touches its body (right), the Subject Exposure level may give the impression that exposure is good.

Wait that the subject’s tail does not touch its body, and check the Exposure Level for a more reliable indication.