--- title: "Calibrate video cameras" canonical: "https://help.vicon.com/space/Nexus218/406487911/Calibrate%20video%20cameras" format: markdown --- Video cameras are calibrated as part of the normal calibration process described in [Calibrate Vicon cameras](https://vicon-help.atlassian.net/wiki/spaces/Nexus218/pages/406488171). However, if you want to perform a video-only calibration or need to check or adjust video calibration setup settings to to make sure centroids are captured during calibration, use the following process. > ℹ️ **Video-only calibration** > ℹ️ Nexus 2.18 and later includes support for video-only calibration. With video-only calibration, you can dynamically calibrate and set the origin of your system without the need for any optical cameras. This process is compatible with any supported reference video cameras (Vicon Vue, FLIR) and works with any Vicon Active Wand variant. For more information about compatible hardware, contact [Vicon Support](#). **To set up calibration for video cameras:** 1. Make sure your video camera(s) are set up in the volume, as described in [Configure video cameras for digital video capture](https://vicon-help.atlassian.net/wiki/spaces/Nexus218/pages/406487883). 2. Power on the wand in **Strobe** mode. :check_mark: **Video only calibration**: If you are calibrating only video cameras, set the wand to **Continuous** mode. 3. In the **System Preparation** panel, go to the **Video Calibration Setup** section at the top and click **Activate** to start video calibration mode. The current configuration settings are displayed. These are the same settings that are available when you click Start under Calibrate Cameras, as described in Step 8 of [Calibrate Vicon cameras](https://vicon-help.atlassian.net/wiki/spaces/Nexus218/pages/406488171), and are used during calibration. :info: **Note**: The settings for some video camera properties may differ in video calibration setup mode from those in live capture mode. For these properties, any changes you make after you click **Activate** only apply during video calibration setup mode. The properties revert to their live capture settings after you click **Deactivate**. 4. Calibrate the system as normal (see [Calibrate Vicon cameras](https://vicon-help.atlassian.net/wiki/spaces/Nexus218/pages/406488171)), making sure that the video camera receives sufficient wand waves. The best way to do this is to leave the **Auto Stop** option selected with the default settings. 5. To exit video calibration mode and return to your settings for live captures, click **Deactivate** in the **Video Calibration Setup** section. > Macro (scroll-pagebreak) ## Calibrate a FLIR Blackfly S camera When you calibrate a FLIR Blackfly S camera, the default settings usually result in a good calibration. These notes are provided to help you to understand FLIR Blackfly S camera parameters and behavior. > Macro (toc) ### Set a large enough Area of Interest window We strongly recommend setting the Area of Interest window at least as large during calibration as will be used during capture. If in doubt, use the default setting of the whole image for both calibration and capture. ### Set an appropriate frame rate We recommend calibrating using at least the video rate that will be used for capture. The calibration of FLIR cameras in Nexus does not check for timing offsets (unlike say, calibrating an SDI camera in Shogun Live), as the timing of the camera is controlled directly using the Vicon Lock unit. This means you can change the frame rate and exposure of the video camera after calibration or decrease the Area of Interest window size. However, do not alter the aperture of the lens without re-calibrating. ### Check warnings A known issue results in warnings being briefly generated when you change camera parameters, including when you enter and exit calibration mode. If continual warnings about timing, missing triggers or black frames being inserted occur, calibration is unlikely to be successful, so ensure that the video is stable before continuing. > Macro (scroll-pagebreak) ### Use Video Calibration Mode 1. To tune the video threshold and calibration shutter duration, in the **System Preparation** panel, go to **Video Calibration Setup** at the top and click **Activate**. This activates a number of parameters in the **System Resources** panel. In video calibration mode, the image becomes much darker, ideally so that only the strobes can be seen. 2. Power on the wand in **Strobe** mode. :check_mark: **Video only calibration**: If you are calibrating only video cameras, set the wand to **Continuous** mode. 3. Check that centroids can be seen in the video image. If not, you may need to adjust the parameters until the centroids become visible. ### Adjust the threshold if required In most cases, the default threshold usually works well. However, in extreme circumstances, you can adjust this setting if the wand LEDs are not reliably detected. ### Check camera masks Check that masks are sensible (ie, covering any bright objects, but not covering a very large portion of the image). If masks are too large, it is likely that the calibration settings are inappropriate. ### Carry out wand wave Calibrate the system as normal (see [Calibrate Vicon cameras](https://vicon-help.atlassian.net/wiki/spaces/Nexus218/pages/406488171)), making sure that the video camera receives sufficient wand waves. The best way to do this is to leave the **Auto Stop** option selected with the default settings. > Macro (scroll-pagebreak) ### Check the calibration After calibrating, you can carry out a quick check. 1. Start a capture. 2. Wave the wand quickly in front of the video camera. 3. Stop the capture. 4. Transfer the capture to video (MP4 or AVI) so it can be played back and stepped through. 5. Step through and verify that reconstructions are shown in the correct place. (They will still be very slightly offset, owing to the difference between the physical position of the visible and IR strobe LEDs on the wand.)