Knowledge Base

Adjust the Settings for Nose-Tail Base Detection (Contour-Based)

Aim

To achieve detection of the nose- and tail-base points of your subjects with high accuracy.

Prerequisites

• In the Experiment Settings, under Tracked Features, you chose Center-point, nose-point and tail-base detection.
• You have optimized the lighting and the background. See Optimize Nose-Tail Base Detection.

Procedure

1. Select the image source and sample rate. See Video File, Image Quality and Sample Rate.
2. Use the Automated Setup. When the Automated Setup gives good detection, proceed with acquisition. If not, follow the steps below. See Detection Settings: Automated Setup.
3. Under Video, choose the sample rate. Use a sample rate as high as possible. However, for nose-tail tracking in combination with marker-assisted tracking, use a sample rate of 12.5, 15 or 14.98 samples/s depending on the camera.
4. Open the Advanced Detection Settings: Method. Choose the detection method and the method for estimating the body points. See Methods for Estimating the Body Points. If you followed the Automated Setup, a Default method is selected automatically for one-subject tracking, and For Occlusions for multiple-subject tracking.

In the picture below: Left, a sub-optimal result of body detection (part of the right side of the body is not detected). Right, the result when the contrast settings are optimized; now the complete body is detected. The color of the body contour at this stage is orange (=noise) because the model parameters have not been configured yet.

Notes

• The maximum sample rate depends on the camera.

Subject Contour for Nose-Tail Base Detection

Aim

To optimize the shape of the detected subject, so that the body points are correctly found.

Procedure

• When you use one of the following methods for detecting the body points, Any Species / Default, or Adult Fish / For Occlusions, make sure the tail is fully detected as part of the subject.
• When you use a Rodents method (Default or For Occlusions), it is best to remove detection of the rodent's tail. See Advanced Detection Settings: Subject Contour.

Notes

• When you track fish from above, the tail-base point is not positioned on the tail fin, rather more towards the mid-point. That is normal and is not a sign of bad detection.

See Also

• Advanced Detection Settings: Subject Contour
• Subject Size for Nose-Tail Base Detection

Subject Size for Nose-Tail Base Detection

Aim

To optimize the size of the detected subject, so that the body points are correctly found.

Procedure

Choose the option depending on which method for estimating the body points you are using.

• For Any Species / Default or Rodents / Default: See Advanced Detection Settings: Subject Size (one subject per arena).
• For Rodents / For Occlusions and Other Species / For Occlusions: See Advanced Detection Settings: Subject Size (multiple animals per arena).