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camera calibration and image stabilization

Camera calibration

Calibrate a camera rig once and reuse that calibration for image stabilization on later captures.

Camera calibration vs image stabilization

  • Camera calibration computes the position and orientation of each camera from a captured dataset. It establishes how the cameras are arranged around the subject and creates a reference that later captures can reuse.
  • Image stabilization applies that calibration to crop and warp the captured images so the subject stays centered and stable across the cameras. Calibration describes the rig; stabilization adjusts the images.

Calibrate your first dataset

  • Frame the subject in the center so each camera sees the same central point.
  • Use even, stable lighting and avoid flicker, harsh shadows, or blown highlights.
  • Keep the subject still so every camera captures the same moment in time.
  • Prefer textured clothing or surfaces so the alignment engine can match the same 3D environment more reliably.

After taking the shot, click Calibrate in Quickview, or find the dataset in Library and open its Calibration tab.

Choose a calibration engine

Starter and Basic license tiers support Xangle Cloud only. Local calibration engines require a Camera Server license tier that includes local calibration, as well as any license required by the engine provider.

  • Xangle Cloud calculates a 3D rig calibration on Xangle-hosted servers with no local install. Use this when you want managed processing and fast setup.
  • Spirula is a free local calibration engine. It is fast, but may fail with complex camera setups or poorly positioned cameras.
  • RealityScan is a desktop rig calibration workflow via RealityScan (Epic Games, Windows only). Use this when you want a local 3D workflow and reusable calibration files for later processing.
  • 3dflow / FlowEngine is a local calibration engine suited to small and complex camera setups. It requires a license from 3Dflow and a configured FlowEngine helper.

Engine comparison

On clean, properly lit datasets, calibration engines can produce stable results. For the best result, follow the capture guidelines above.

  • Xangle Cloud: Efficiency 7/10. No extra app to install. It works well in most cases when the subject is properly lit and framed as described above.
  • Spirula: Efficiency 7/10. Fast and free, but it may fail with complex camera setups or poorly positioned cameras.
  • RealityScan: Efficiency 9/10. Excellent quality in most setups, but it requires a RealityScan license from Epic Games and runs on Windows only.
  • FlowEngine: Efficiency 9/10. Efficient and effective for small and complex camera setups. Requires a license from 3Dflow.

Set up your engine

Xangle Cloud

  • Xangle Cloud calibration runs on Xangle workers, so no extra software installation is required.
  • Images are uploaded only for the active job and are deleted after results are downloaded.
  • Cloud calibration uses Cloud Credits per submitted image. See current rates.
  • Credits are consumed only when the cloud calibration job completes successfully.

Spirula

  • Download and install Spirula. Camera Server can auto-detect it in the standard install location, or you can set the executable path in Rig Calibration settings.
  • Spirula is free to use. It may fail with complex camera setups or poorly positioned cameras.

RealityScan

Epic's official install flow is:

  1. RealityScan runs on Windows only. Download and install the Epic Games Launcher from the official RealityScan download page.
  2. Open the launcher, create or sign in to your Epic Games account, then open the RealityScan tab under the Unreal Engine section.
  3. Install the latest RealityScan build. In Camera Server, you can usually leave the RealityScan path empty so it auto-detects the install under C:\Program Files\Epic Games.
  4. If RealityScan was installed somewhere else, paste the executable path manually in Rig Calibration settings.
  5. Run one calibration dataset from Rig Calibration or Library to confirm Camera Server can launch RealityScan headlessly.

Cost and licensing

  • Epic currently lists RealityScan as free for students, educators, educational institutions, and individuals or companies under $1 million USD in annual gross revenue.
  • Above the $1 million USD revenue threshold, Epic sells yearly RealityScan seats. The public license page currently lists CA$1,697 per seat per year and also advertises a 30-day trial.
  • Check the official RealityScan licensing page before budgeting or purchasing seats, because public pricing and terms can change.

Learning and support

  • Epic Developer Community provides RealityScan documentation, tutorials, sample datasets, and community forums when you need to learn the tool or troubleshoot the install.

FlowEngine

  • Obtain the required license from 3Dflow.
  • In Rig Calibration settings, select 3dflow / FlowEngine and check that the FlowEngine helper is available.
  • If the helper is not detected, configure its executable in FlowEngine helper path.
  • Run a calibration dataset from Rig Calibration or Library, then review the result in the 3D viewer.

Review and activate the calibration

Open the dataset in Library, then open its Calibration view. Review the calibration through the 3D model in the sparse point cloud viewer: check that the camera positions and reconstructed subject match the physical rig.

When the result looks correct, promote that dataset as the active rig calibration from the dataset menu in Library or from the Rig Calibration module itself.

Reuse calibration for image stabilization

Future datasets on the same untouched rig can reuse the active calibration automatically. You do not need to run a new camera calibration for every capture; image stabilization uses the existing calibration to adjust the new images.

Recalibration: when camera positions change

A typical reason to recalibrate is that someone bumped into a camera.

  • If any camera is bumped, re-aimed, re-focused, or moved during the event, capture a fresh calibration shot and promote it as the new rig calibration before continuing.
  • If the rig changes a lot between captures, enable auto re-align for new datasets instead of relying on one long-lived reference.