> For the complete documentation index, see [llms.txt](https://stage-precision.gitbook.io/grid/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://stage-precision.gitbook.io/grid/camera-calibration/camera-calibration-overview.md). # Camera Calibration Overview
Camera calibration in Grid Studio is used to align a real camera system with a virtual scene. This is especially important for virtual production, augmented reality, LED stages, broadcast AR, and any setup where physical camera movement needs to match virtual content accurately. A real camera setup is made from several parts that all need to describe the same physical space correctly: * the physical camera * the lens mounted on the camera * the tracking system or camera movement data * the virtual scene inside Grid Studio * known physical reference surfaces, such as LED walls, monitors, printed boards, or other precisely measured calibration targets If these parts are not calibrated correctly, virtual and physical elements may not line up. This can cause incorrect perspective, wrong parallax, visible offsets, or virtual objects appearing to float or slide against the real camera image. ## Why Camera Calibration is Required Camera calibration creates an accurate virtual representation of the physical camera system. Grid Studio uses calibration to understand how the real camera sees the world, how the lens distorts the image, how camera tracking or movement data relates to the actual camera view, and where known physical screens or reference surfaces are located in the virtual stage environment. A complete camera setup can involve three major calibration areas: * Lens Calibration * Tracking Calibration * Screen or Reference Surface Calibration These areas are closely related, but they solve different parts of the overall alignment problem. *** ## Lens Calibration Lens calibration describes the optical behavior of the camera lens. Real lenses usually introduce distortion, especially wide-angle lenses or lenses with strong perspective characteristics. Without lens calibration, virtual elements may be rendered with a different image shape than the real camera image. By calibrating the lens, Grid Studio can compensate for this distortion and make sure that virtual content follows the same optical behavior as the real camera image. Lens calibration can create a Lens Profile. A Lens Profile can often be reused across different setups, as long as the same lens and lens settings are used. *** ## Tracking Calibration Tracking calibration defines how camera tracking or movement data relates to the actual camera view. A tracking system may provide position and rotation data, but this data does not automatically describe the exact optical center and viewing direction of the camera. The tracker may be mounted above, behind, or next to the camera body, and therefore has an offset from the real camera view. Tracking calibration allows Grid Studio to calculate this relationship so that the virtual camera matches the movement and perspective of the physical camera. Tracking calibration can create or update an Alignment Profile. An Alignment Profile describes how the camera, tracking data, lens, and reference setup relate to the virtual scene. Different camera movement setups may require different calibration tools. For example, a fully tracked camera system is calibrated differently from a pan/tilt camera or a camera moving on a rail or axis. *** ## Screen and Reference Surface Calibration Calibration Screens are not only used as visual references. Some calibration workflows can also calculate and update the **position, orientation, and shape** of these known physical reference surfaces inside the virtual scene. This is important because the real reference surface may not be perfectly positioned, perfectly flat, or perfectly aligned in the project. During calibration, Grid Studio can use the detected Calibration Patterns to refine how the surface exists in 3D space. In many setups, the reference surface is an LED wall. However, it can also be a monitor, TV, printed board, or another physical calibration target with precisely known dimensions. The important part is that Grid Studio knows: * the real physical size of the reference surface * the pixel resolution of the Calibration Image * the position of the Calibration Pattern markers on that surface Grid Studio can generate Calibration Images that are displayed or placed on these reference surfaces. These images are used as known visual references during the calibration process. For digital screens such as LED walls, monitors, or media-server outputs, the Calibration Image must be displayed pixel-correctly. For printed boards, the physical print size must match the dimensions configured in Grid Studio. Projection-based marker workflows are not part of the standard Calibration Image workflow, because the final projected marker size can be difficult to guarantee accurately unless it is measured and controlled separately. Calibration Screen objects are usually created and configured before calibration. Calibration tools do not create the Calibration Screen objects themselves. Instead, they can optionally calculate and apply the screen placement, orientation, and shape in 3D space. {% hint style="info" %} If Calibration Screens are already positioned correctly, screen repositioning can usually be disabled in the calibration workflow. If screen repositioning is enabled, the Calibration Screen placement or shape may be updated by the calibration result. {% endhint %} *** ## Calibration, Repositioning, and Alignment Tools Grid Studio provides different calibration, repositioning, and alignment tools depending on the physical setup and the part of the system that needs to be created, updated, or corrected. Calibration tools are usually used to create or update calibration data such as Lens Profiles, Alignment Profiles, axis calibration data, or screen placement information. Repositioning tools are used when existing calibration data is already available, but parts of the setup need to be moved, aligned, or updated. For example, a screen may have moved, a camera may need to be repositioned from known markers, or an existing stage setup may need to be aligned again without changing the underlying Lens Profile or Alignment Profile. Most calibration tools also provide options that define which parts of the result should be solved, updated, or reused during the calibration. For example, a tool may solve lens data, update tracking alignment, calculate screen placement, or reuse an existing screen setup. This is important when only parts of the setup have changed. If a second camera or tracking system is calibrated on a stage where the screen setup is already valid, the screen-related parts of the calibration can usually be disabled or reused. The calibration can then focus only on the parts that are different for the new camera or tracking system. The correct workflow therefore depends on two decisions: 1. Which calibration or repositioning tool matches the physical setup? 2. Which parts of the setup should this tool solve, update, apply, or reuse? *** ## Manual Markers / Measurement Points Some calibration workflows can use manually referenced 3D points instead of Calibration Screens. In the calibration tools, this workflow is referred to as **Manual Markers**. The actual point objects created in the Project Tree are called **Measurement Points**. A Measurement Point stores a known 3D position in the project. During calibration, the user manually assigns this point to its matching pixel position in captured camera images. Manual Marker workflows are useful when Calibration Screens cannot be used, for example in stadiums, arenas, venues, stages, or architectural environments. *** ## Workflow at a Glance At a high level, a typical calibration workflow follows these steps: 1. Prepare the Grid Studio project and required objects. 2. Make sure the camera image and any required tracking, movement, encoder, or axis data are available. 3. Create or configure the required calibration screens, reference surfaces, or Manual Markers. 4. Choose the correct calibration, repositioning, or alignment tool for the setup. 5. Decide which parts of the setup should be solved, updated, applied, or reused. 6. Capture the required calibration samples or reference observations. 7. Solve the calibration or repositioning process. 8. Apply the result to the generated profile, object, screen setup, or parent object. 9. Validate the result in the virtual scene. The following sections explain how to prepare the project, choose the correct tool, create calibration references, and perform the individual calibration and repositioning workflows.