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Lenses API

The Lenses API allows you to manage camera lens parameters and calibration data for multi-camera motion capture setups.

Overview​

Camera lenses are essential components in multi-camera motion capture systems. The Lenses API helps you:

  • Store and retrieve lens calibration parameters
  • Manage lens metadata for different camera setups
  • Ensure accurate 3D reconstruction from multiple camera views

Lens parameters​

Focal length​

The focal length determines the field of view and magnification of the lens:

{
  "focal_length": {
    "fx": 1000.0,
    "fy": 1000.0
  }
}

Principal point​

The principal point is the optical center of the lens:

{
  "principal_point": {
    "cx": 960.0,
    "cy": 540.0
  }
}

Distortion coefficients​

Lens distortion correction parameters:

{
  "distortion": {
    "k1": 0.1,
    "k2": 0.05,
    "p1": 0.001,
    "p2": 0.001
  }
}

API endpoints​

Get lens details​

Retrieve lens parameters for a specific lens.

GET /api/lenses/{lens_id}

List lenses​

Get all available lenses for your account.

GET /api/lenses

Create lens​

Create a new lens configuration.

POST /api/lenses

Update lens​

Update lens parameters.

PUT /api/lenses/{lens_id}

Delete lens​

Remove a lens configuration.

DELETE /api/lenses/{lens_id}

Lens calibration​

Calibration process​

  1. Setup: Mount camera with lens in fixed position
  2. Capture: Record calibration object from multiple angles
  3. Processing: Calculate lens parameters using calibration software
  4. Storage: Save parameters via Lenses API

Calibration data format​

{
  "lens_id": "lens_123",
  "camera_model": "Sony A7III",
  "lens_model": "Sony 24-70mm f/2.8",
  "focal_length": 50.0,
  "sensor_size": {
    "width": 35.6,
    "height": 23.8
  },
  "resolution": {
    "width": 1920,
    "height": 1080
  },
  "intrinsics": {
    "focal_length": [1000.0, 1000.0],
    "principal_point": [960.0, 540.0],
    "distortion": [0.1, 0.05, 0.001, 0.001]
  },
  "created_at": "2024-01-15T10:30:00Z",
  "updated_at": "2024-01-15T10:30:00Z"
}

Best practices​

Lens selection​

  • Fixed focal length: Use prime lenses for consistent results
  • Quality: Higher quality lenses provide better calibration accuracy
  • Stability: Ensure lens doesn't change focal length during capture

Calibration​

  • Multiple positions: Capture calibration object from various angles
  • Good coverage: Ensure calibration covers the entire capture volume
  • Validation: Test calibration accuracy with known movements

Maintenance​

  • Regular checks: Recalibrate if lens parameters change
  • Documentation: Keep detailed records of lens configurations
  • Backup: Store calibration data securely

Next steps​