Knowledge Base

5.2 Carry Out Data Acquisition

After you have prepared the walkway, you are ready to start data acquisition. During acquisition, CatWalk XT uses the run criteria you have specified in the Experiment Settings.

Start Data Acquisition

1. Do one of the following:
   • In the Experiment Tasks window, click Open Acquisition.
   • Choose Acquire > Open Acquisition.
   • In the Experiment Explorer, under Acquisition, right-click a trial and select Acquire Runs.
2. Under Trial Selection, select a trial from the list. When you have not defined one or more trials in the Trial List, select Create New Trial from the list or go to the Trial List to define trials. Lower the illuminated ceiling gently; if you do this too roughly, it can make the corridor walls shake which can accidentally set off acquisition after you have clicked the Start Acquisition button. Do not lift the illuminated ceiling after you have clicked the Start Acquisition button, as this results in the acquisition of a lot of data and a high processing load.
3. Click the Snap Background button to snap a background image of the empty, clean walkway. You cannot start acquisition before you have snapped a background image. You can view the background image in the Acquisition Settings by choosing Setup > Acquisition Settings and clicking the View Background Image button.
4. Click Start Acquisition or press Page Up. The status changes to Waiting for run to start.
5. Optionally, check the walkway by pressing Validate Walkway. A dialog showing the full walkway appears, indicating where the corridor walls are detected. If the corridor walls are not parallel to the walkway or to each other, a warning appears. If everything is acceptable, a green message Walkway looks good appears.
6. Put the animal into the corridor from the side. Acquisition starts automatically as soon as the animal's contour is detected. The status changes to Recording Run#. As soon as the animal disappears from view, the status changes to Waiting for run to start.
7. If you have specified in the run criteria of the Experiment Settings to acquire more than one compliant run, take the animal out of the corridor and put it back in on the other side, or let it turn around for the next run.

Stop Data Acquisition

1. You can manually stop data acquisition by clicking the Stop Acquisition button or by pressing Page Down.
2. Acquisition stops automatically as soon as the set number of compliant runs has been acquired.

What Next?

When the set number of compliant runs has been acquired, the Acquisition Finished Tasks window opens. You can now select:

• Acquire Next Trial – This is the trial listed next in the Trial List.
• Acquire New Trial – This creates a new trial that you can acquire.
• Classify Runs – This takes you to the Classification window where you can classify acquired runs.
• Review Runs – To inspect acquired runs.

Acquired Run List

The Acquired Runs list shows the acquired runs with the following variables:

• Run – The run number.
• Start – The start date and time of the run.
• Duration – The total duration of the run.
• Compliant – A run is marked compliant or non-compliant with the run criteria. When you hover over the non-compliant icon, information is displayed about why the run is non-compliant. The run criteria become read-only when you have acquired a run.
• Direction – The walking direction of the animal. If the animal turns around, the direction cannot be determined.
• Run Average Speed – The speed of the recorded run.
• Run Maximum Variation – The maximum variation in running speed of the recorded run.
• Camera Gain – The Camera Gain value from the Detection Settings.
• Green Intensity Threshold – The Green Intensity Threshold value from the Detection Settings.

Depending on your Run Settings in the Acquisition Settings, runs that are aborted or do not meet the run criteria are kept or discarded.

A run stops automatically:

• When the run duration exceeds the maximum set in the run settings.
• In any case when run duration exceeds 60 seconds. This is indicated for that run in the Acquired Runs list.

Acquisition stops automatically:

• When the set number of compliant runs has been acquired.
• When not enough internal memory is available. This can occur, for example, when you acquire a number of long runs (20–30 seconds) in a row with short time between runs. In this case, CatWalk XT needs to both process and acquire long runs, which can cause the internal memory to overflow.

Acquisition Status

The status during acquisition can be:

• Waiting for background snapshot of empty walkway to be taken – Press the Snap Background button. You can view the snapped background in the Acquisition Settings.
• Ready for acquisition – Press the Start Acquisition button.
• Waiting for run to start – Recording starts automatically as soon as the animal appears in the video image.
• Recording Run[#] – A run is being recorded and acquisition stops automatically as soon as the animal has completely disappeared from the video image.
• Camera connection lost, trying to restore the connection – If the connection is lost, acquisition is stopped. Acquisition can only be resumed after the connection has been restored.
• Waiting for animal to leave the walkway – This status message is shown in the following cases:
  • The maximum run duration has been exceeded while the animal is still on the walkway.
  • The animal has left the walkway but has left some faeces or urine so the run has not been stopped.