Knowledge Base

Video Settings and Camera Configuration

When Three Body Points Are Tracked

• When you track the three body points in general.
• You work with Behavior Recognition. See Behavior Recognition: Requirements.
• You track the subjects with the Deep learning technique. See Deep Learning: Requirements.

Frame Rate

This is the number of video images per second that are generated by the camera. Note that the frame rate is not the same as the Sample rate, which is the number of images EthoVision XT analyzes per second.

• For digital cameras, the frame rate can vary. Common values are 25 and 30. A frame rate higher than 30 is recommended when working with fast-moving animals, or when you want to detect movements like startle responses in fish or rapid turns in flying insects. High frame rates require more processing power. If you select a high frame rate, in some cases you need to lower the video resolution. This window shows a message when that is the case. See the tested configurations in GigE Cameras.
• For analog cameras, the frame rate is determined by the TV standard of your camera.

Color Space

This option is available for digital cameras only. Color space determines how the information about brightness and color is encoded in the video frames that are sent to EthoVision XT. Note that this may impact the maximal frame rate. The optimal color space differs between cameras. See also Pixel Format and Color Space.

• For monochrome cameras: Choose Y800. Check the preview image to assess whether the image quality is good.
• For color cameras: If the image is black-and-white instead of color and a Moiré pattern appears in the image, try selecting another color space. Normally, the default color space gives a good image quality. If you use a high frame rate or resolution, this reduces the number of animals you can track simultaneously. This also depends on how fast your computer is.

In the Detection Settings, in the Detection Performance pane, check the value under Missed Samples to get an indication of the quality of tracking. See also Settings for the Color Camera and Pixel Format and Color Space.

Standard

This is only available for analog cameras. Select the TV standard of your camera. You can find this in the specifications section of your equipment's manual. It will probably be the standard used in your country.

• PAL: In Western Europe, China, Indonesia, and Australia.
• NTSC: In United States, Canada, and Japan.

Image Tab

Brightness, Contrast, and Saturation are only available for analog cameras. Move the slider, click the arrows, or change the number in one of the fields to adjust the settings and check the resulting image. Click the Default button to revert the Image settings to default. The settings on the other tabs will not change. Click the More Settings button to open a window with additional settings.

Brightness

Be aware that a too dark or too bright image may reduce the quality of video tracking. Brightness is not the same as Exposure; the latter is the period of time when the camera sensor is exposed to light.

Contrast

This is the difference in brightness or color that makes objects in an image distinguishable. Use this slider to enhance or reduce the contrast in the image.

Saturation

This is the strength or purity of the color and represents the amount of gray in proportion to the hue. A saturated color is pure, while an unsaturated color has a large percentage of gray.

Camera/General Tab

Some options are only available for Basler cameras.

Center Image

When selected, Center Image ensures that the resulting camera image is centered over the sensor when not capturing the largest possible image. We recommend keeping this option selected. See also Center the Camera View.

Binning

Use Binning when you want to reduce the video size and increase brightness without cropping the video image. When selected, sensor pixels are grouped together to make one image pixel. For example, selecting 2 means that two horizontal and two vertical pixels, thus 4 sensor pixels, make up one image pixel. This increases the sensitivity of the camera but reduces the size of the video image. For example, setting binning to 2 reduces the video size from 800 x 600 to 644 x 513. Note that the image is just smaller, not cropped.

• Binning results in a brighter image. Check that detection is still optimal. To reduce brightness, close the aperture ring of the camera lens, or reduce the Exposure time or the Gain.
• When you select or deselect Binning, do that for all the cameras in your experiment. Binning should be the same across the cameras.
• If you want to reduce the video size and crop the video image, clear the Binning option, keep Center Image selected, and reduce the resolution.
• You can also crop the video image when your camera lens is multi-focal (that is, the lens has a zoom ring).

Exposure Time

Exposure determines the time when the sensor is exposed to light. The higher the value, the brighter the image. Note that if Exposure is too high, the camera may not be able to send images at the required frame rate. In that case, the window shows that the frame rate is too low. Reduce the Exposure, or reduce the frame rate to allow longer time intervals between subsequent video frames.

• For zebrafish larvae, enter 4000 or 2000, depending on the video resolution chosen; the smaller the resolution, the shorter the exposure time needed.
• For rodents in an open field, a value between 5000 and 20000 is appropriate.
• For a mosquito filmed under infrared, a value around 10000 is appropriate.
• All else being equal, faster animals require shorter exposure times.

If the image becomes too dark due to a short exposure time, increase the Gain.

Gain

Adjust the Gain to change the amplification level of the signal coming from the camera sensor. A higher value means more sensitivity. Increase the gain to make the picture brighter, for example in dark environments. Be aware that higher Gain may increase noise in the image.

Default/More

• Click the Default button to change the camera settings back to default. The settings on the other tabs will not change.
• Click the More button to open the camera software with additional settings. To operate this software, click the Cancel button in the EthoVision XT Video Settings window first.