# Adjust camera settings in EthoVision XT

Aim

To adjust the settings of your camera within EthoVision XT. For example, the video resolution, the frame rate, or the exposure.

important To improve the quality of the image, always try adjusting the lighting and camera aperture before changing the settings in EthoVision XT.

Prerequisites

▪If you work with Basler digital cameras, before using the camera in EthoVision XT close the camera software Pylon Viewer.

To access the camera options

1.Choose Setup > Experiment Settings, and click the camera button for the camera you require.

2.Click one of the tabs and adjust the settings (see below).

▪Format tab

▪Image tab

▪Camera/General tab

▪Color tab

▪Address tab

▪More settings

Format tab

The Format tab is only available for the first camera. The settings you specify here are also applied to the other cameras.

important If you change the resolution within an experiment, open the Arena Settings profile and Grab the background image. This will update the background image with the new resolution. If the Arena Settings profile is locked, right-click it and select Duplicate. In the new profile you can now grab the background image. Next, use that Arena Settings profile to acquire new trials.

Resolution

For single arenas and subjects more than a couple of centimeters long, a resolution of 384x288 (analog cameras, PAL) or 320x240 (analog cameras, NTSC) or 640 x 480 (GigE cameras) is sufficient.

For digital cameras: When you reduce the resolution, the field of view also changes. In the following example, reducing the resolution from 800 x 600 to 640 x 480 results in a cropped image.

You can compensate for this if your camera is provided with a zoom lens. Another option is to leave the resolution unchanged and use the Binning function which reduces the size of the image in pixels but does not affect the field of view.

If you opt for a higher resolution in GigE cameras, for example 1280 x 1024, always check that it does not conflict with the frame rate (see below).

▪The higher the video resolution, the more accurate your tracking.

▪The higher the video resolution, the larger the resulting video files. If disk space is limiting, use the above-mentioned resolution.

▪Use a high resolution especially:

▪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 the 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 Moire 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.

tip 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/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 to keep this option selected. See also Center the camera view

Binning

Use Binning when you want to reduce the video size, 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.

In the following figure, 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.

Note:

▪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 the images at the supposed frame rate. In that case, the window shows that the frame rate is too low. Reduce the Exposure, or reduce the frame rate to have 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 fine.

▪For a mosquito filmed under infrared, a value around 10000 is fine.

▪All else being equal, faster animals require shorter exposure times.

tip If the image becomes too dark due to the short exposure time, increase the Gain (see below).

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 first the Cancel button in the EthoVision XT Video Settings window.

Color tab

Gamma

Human visual perception is typically non-linear. Adding 1 to a dark or bright color would not result in the same increase in the perceived brightness. Gamma adjusts the brightness of pixel values to account for this non-linearity. Choose sRGB to take a colors as is. Choose user to fine-tune the color representation and get a color perception that is optimal for you.

When the gamma correction value is set to 1, the output pixel brightness is not corrected. A value between 0 and 1 results in increased overall brightness; a value greater than 1 results in decreased overall brightness.

Color adjustment

With Color adjustment you can fine tune the color perception by adjusting the settings of colors separately. Select Enable, then choose a color from the list and adjust the saturation Value. Check the result in the image preview.

Address tab

This contains the settings for IP cameras.

IP Address

Enter the IP address of the IP camera. For details about how to define a IP address for the camera, see the Help of EthoVision XT 17 or earlier, which you can download from my.noldus.com.

Port

Enter the port number specified for the IP camera (default for Noldus cameras: 554).

User name

Enter the user name specified for the IP camera. For details on how to define a user, see the Help of EthoVision XT 17 or earlier, or consult the camera’s manual.

Password

Enter the password specified for the IP camera. For details on how to set a password, see the camera’s manual.

More settings

For some types of cameras the More button takes you to additional settings. For example, for GigE cameras:

These settings corresponds to those you can access with the camera software (see Configure the digital camera). The main settings are:

▪Analog Controls > Gain. Increase the value of Gain Raw to increase light intensity. Note that this also increases background noise.

▪AOI Controls > Resolution. See Format tab above for this setting.

▪Acquisition Controls >

▪Exposure time. Increase the value of Exposure time to have a brighter image. However, a long Exposure time may conflict with other settings, in particular frame rate. See Configure the digital camera

▪Acquisition frame rate. See Format tab above for this setting.

Notes

▪For digital GigE or USB 3.0 cameras, all settings are available in the camera software. See Configure the digital camera

▪When you adjust the camera settings in EthoVision XT, the settings are sent back to the camera once you re-open the experiment.

▪The camera settings are saved at the experiment level. So you can create two EthoVision XT experiments with different camera frame rates, exposure levels, etc.

See also

▪Configure the digital camera

▪Check that the camera is set up properly