# 10 — Camera Model

## Status

```text
CAMERA_MODEL_V1=FROZEN
```

## Authority

`docs/architecture/sparse_sfm.md` and calibration contracts.

## FROZEN

Sparse SfM v1 is known-calibration only.

The v1 model is binary64 pinhole with zero skew and OpenCV-compatible distortion:

```text
fx, fy, cx, cy
k1, k2, p1, p2
```

or explicit zero distortion.

Image coordinates: top-left origin, +x right, +y down.

Camera frame: x right, y down, z forward.

Pose is world-to-camera:

```text
Xc = R_cw * Xw + t_cw
Cw = -transpose(R_cw) * t_cw
```

Higher-order lens models are outside this FROZEN v1 boundary unless separately authorized and scientifically contracted.

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