Knowledge Base

EthoVision XT Settings

Background Changes

Adjust the slider until the subjects are properly detected. From the Background changes list, select an option that reflects your conditions (usually, Medium slow works just fine).

Contour Erosion/Dilation

You need Contour erosion/dilation to get a smooth contour without the tail for accurate modeling and to remove individual pixels of noise.

To improve detection, open the Advanced section in the Detection Settings pane. Under Subject Contour, select one or more pixels for the first Erosion filter and the Dilation filter. Leave the second Erosion filter to zero. Increase the number of pixels for Erosion until the animal's tail is removed, then increase Dilation until the entire animal's body contour is detected.

Subject Size

Before you set the Subject Size, make sure the animals are properly detected and do not touch each other.

Click Subject Size, then click Advanced.

1. Under Modeled subject size, make sure the Apply to all subjects and Fix (for all subjects) options are selected.
2. Click the Grab button. This adjusts the Average size to the Current size.
3. Repeat clicking the Grab button until the body fill completely fits the animal.

Shape Stability and Modeling Effort

The Shape stability setting is used when you track animals whose body can be occluded by, for example, cage bars or part of the body of another animal.

• When you set the slider closer to Occlusions, EthoVision considers separate objects that are close together part of one animal.
• When you set the slider close to Noise, EthoVision considers separate smaller parts not part of the animal.

The Modeling effort setting is used when two animals touch and EthoVision loses the separate shapes. At this point, EthoVision tries to determine which part of the large merged blob belongs to either animal, using a lot of processor load in the process.

• When you set the slider close to Performance, EthoVision is only allowed a short time to determine which part of the merged blob belongs to which animal. Therefore, modeling quality is low.
• When you set the slider to Modeling, EthoVision is allowed a longer time to determine which part of the merged blob belongs to which animal. Therefore, modeling quality is good, but this costs a lot of processor load. If you track from video, video tracking slows down.

Trial List

Enter your independent variables such as rat ID, treatment (drug vs. control), dose, name of the experimenter, etc. You can predefine all your trials here, or you can enter the independent variable values as you carry out the trials. You can also prepare the trials in Excel, randomize them, and then paste the values into your Trial List.

Notes

• When using color markers, add a Marker color variable to the Trial List to specify the marker color you assigned to each Subject role. This is useful when you have defined, for example, the Subject name Experimental and Stimulus, or Subject 1 and Subject 2, and you have randomly assigned the marker colors to the Subject roles.
• You can define a series of trials for batch acquisition. See Acquire a series of trials in the EthoVision XT Help.

Source: EthoVision XT 18 - Application Manual, Noldus Information Technology