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> For other versions, use one of these documentation indexes:
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> - Dev: https://docs.nvidia.com/vss/dev/llms.txt

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# Auto Calibration

The **Auto Calibration microservice** enables automatic calibration of single-camera and multi-camera systems through a web-based, seven-step workflow.

The service estimates camera intrinsics and extrinsics to generate projection matrices and lens distortion parameters for 3D and multi-view applications.

Unlike checkerboard-based methods, the tracklet-based AMC method uses **naturally moving objects** in the scene. With NVIDIA DeepStream detection and tracking, it follows objects (e.g., people) and derives camera parameters from normal operational footage—no setup, no downtime, and supports calibration from archived videos.

The service supports two calibration methods: a **geometry-based approach (AMC)** that uses object trajectories and geometric relationships, and a **model-based approach (VGGT)** that uses a learned model for multi-camera calibration.

The overall microservice architecture is as shown below:

![Auto Calibration Microservice Architecture](/vss/_fern-img/85675ef3d3d5e9f76af3b0fe411822e19156e1e5d699fd9936c00d2eb4d5fddc.webp)

UI launch screen is as shown below:

![Auto Calibration User Interface](/vss/_fern-img/70ef9f7e2591e8ad9c4b32d4c6534ea9178a0a62fb31dfccd7e16d92c7b92a52.webp)

## Key Features

**Guided Workflow**

* **7-Step Process**: Project Setup, Video Configuration, Parameters, Rectification, Manual Alignment, Execute, and Results
* **Progress Tracking**: Visual indicators for completion status
* **Validation**: Real-time validation of inputs at each step

**Project Management**

* **Multiple Projects**: Create and manage multiple calibration projects
* **Project States**: Track project progress (INIT, READY, RUNNING, COMPLETED, ERROR)
* **Data Persistence**: All project data is saved automatically

**Interactive Tools**

* **ROI Drawing**: Draw regions of interest directly on linear (rectified) video frames or the layout map; no calibration required for pixel-coordinate output
* **Tripwire Configuration**: Define tripwire lines and directions; world-coordinate output requires completed calibration
* **Manual Alignment**: Interactive point selection for camera-to-world alignment
* **Real-time Preview**: See annotations and calibration results immediately

**Dual Calibration Methods**

* **AMC (Auto Magic Calib)**: Geometry-based, tracklet-based method for single-camera and multi-camera calibration
* **VGGT (Vision-Geometry Graph Transformer)**: Model-based method for multi-camera calibration when VGGT support is installed

**Export Options**

* **Multiple Formats**: Export calibration data in various formats
* **MV3DT Compatible**: Export data compatible with MV3DT verification tools
* **World Coordinates**: Full calibration with ROI/tripwire world coordinates
* **Camera Parameters**: Individual camera intrinsic and extrinsic parameters

## Workflow Overview

The calibration process follows a logical 7-step workflow:

1. **Project Setup**: Create or select a calibration project
2. **Video Configuration**: Upload video files or capture time-synchronized RTSP streams, plus the layout image and optional files
3. **Parameters**: Configure scale, focal lengths, and calibration settings
4. **Rectification**: Correct lens distortion automatically or manually, then optionally download rectified videos and parameters
5. **Manual Alignment**: Upload or create camera-to-layout alignment data
6. **Execute**: Verify inputs and run AMC or VGGT calibration with live monitoring
7. **Results**: View results, optionally draw ROI/tripwire annotations, verify them in the layout, and export data

Each step validates inputs before allowing progression to the next step, ensuring a smooth calibration experience.

For deployment instructions and detailed usage, see [Getting Started](/system-components/calibration/auto-calibration/getting-started).