Knowledge Base

8 Detection Settings

What do you want to do? Track one subject per well/enclosure. See below. Track two or more subjects in the same enclosure. See page 67. Use Activity. See page 66.

One Subject Per Enclosure

Choose Setup > Detection Settings > Detection Settings 1. The template experiment contains a Detection Settings profile with DanioVision selected as method.

important If you have upgraded EthoVision XT to version 15 while you

have a DanioVision system older than the DVOC-0040, it is possible

that the DanioVision detection settings method does not give optimal

detection of the larvae with images from your camera. If that is the

case, use another detection method in the Advanced section of the

Detection Settings pane. For details, see the EthoVision XT Help. 1. Click the Auto-detect button.

important Use the Auto-detect button every time you change a

well-plate. 2. The Auto-detect window with a timer appears. Wait until it has disappeared. All larvae should now be detected well. If not, do one or more of the following: Open the Advanced section and move the Sensitivity slider. Moving the slider to the left results in detecting more of the body of the larvae, but also more noise. Moving the slider to the right results in detecting less noise, but also gives less good detection of the larvae. If you see erratic tracks like that in the picture below (right), it means that small groups of pixels at the border of the well are sometimes detected as the larva. Move the Sensitivity slider to the right. If some larvae are not detected while they are in the corner or border of a well, check that the arenas are drawn well. Click the

Show/Hide button on the toolbar and select Arena Features and

then select the check box in front of Arenas. Check that the arenas cover the entire wells. In the picture below, the arena on the right does not cover the left margin of the well. Theref0re, the larva is not detected when swimming in that region. Try to maximize the contrast by opening the aperture of the camera lens (See "check the camera lens" on page 33.) However, make sure the light intensity is equal for all wells (that is, the center and outer wells). Certain compounds dissolved in the water can affect the pigmentation in the larvae, thereby decreasing the contrast of the animal and making detection of the animal more difficult. Make sure that EthoVision XT can still detect all animals after treatment. 3. If detection remains unsatisfactory, adjust the Advanced Detection Settings. The Dynamic subtraction method may give better results.

For an explanation of the options, see Configure Detection Settings

in the EthoVision XT Help.

Activity Analysis

Use Activity to quantify overall activity of your subjects. In the

Experiment Settings (see page 46) select Activity analysis. In the

Detection Settings pane, open the Activity section. Activity is shown by

purple pixels in the video window. Set the Activity threshold in such a

way that movements of the animals are detected and some noise is left.

For more information on activity, see Activity settings in the EthoVision

XT Help. Also watch the video tutorial on Activity analysis.

For more general information on Detection Settings, see Configure

Detection Settings in the EthoVision XT Help.

Multiple Subjects In The Same Enclosure

Prerequisites: in the Experiment Settings, Number of Subjects is set to

2 or higher. 1. Choose Setup > Detection Settings > Detection Settings 1. 2. Click Automated Setup and draw a rectangle around each subject. 3. Under Method, select Advanced Model / Adult Fish or Advanced

Model / Other if the first does not give the expected results when

tracking fish larvae.

note The Advanced Model /Other method is not based on a

modeled fish shape. With this method you cannot track the fish snout and tail. It is only available if the experiment is set to Center- point detection only.

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Source: Reference Manual - DanioVision DVOC-0041