> For the complete documentation index, see [llms.txt](https://docs.multiset.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.multiset.ai/fundamentals/rest-api-docs/camera-intrinsics.md).

# Camera Intrinsics

Estimate focal length, principal point and optional distortion from one to five images of a scene, for cameras with no factory calibration.

Estimate a camera's **intrinsic parameters** (focal length and principal point, with optional lens distortion) from one to five images of the same scene. Use it as a prior when you don't have factory calibration data for a camera.

{% hint style="info" %}
All images in a single request must come from the **same camera at the same resolution**. Sending 1–5 images of the same scene improves the estimate. Images of different resolutions (or from different cameras) are rejected.
{% endhint %}

### Camera Intrinsics API

Make a `POST` request to **`/v1/vps/camera-intrinsics`** with your authentication token. The request is `multipart/form-data`:

* **`images`**: 1 to 5 image files (field name `images`). Each file must be an image and **≤ 15 MB**.
* **`cameraModel`**: optional string, one of `pinhole` (default), `simple_radial`, `radial`, `simple_divisional`. Use a distortion model (`simple_radial` / `radial` / `simple_divisional`) for wide-angle or fisheye lenses.

The endpoint is synchronous and returns the estimated intrinsics in the response.

#### Sample Request

```bash
curl -X POST "https://api.multiset.ai/v1/vps/camera-intrinsics" \
  -H "Authorization: Bearer <ACCESS_TOKEN>" \
  -F "images=@frame_01.jpg" \
  -F "images=@frame_02.jpg" \
  -F "cameraModel=pinhole"
```

#### Sample Response

```json
{
    "requestId": "b1c2d3e4-....",
    "cameraModel": "pinhole",
    "imageCount": 2,
    "intrinsics": { "fx": 1462.3, "fy": 1462.3, "px": 960.0, "py": 540.0 },
    "resolution": { "width": 1920, "height": 1080 },
    "focalUncertainty": 12.4,
    "focalUncertaintyRatio": 0.0085,
    "distortion": null
}
```

### Reading the Result

* **`intrinsics.fx` / `intrinsics.fy`**: focal length in pixels. **`px` / `py`**: the principal point (image centre).
* **`resolution`**: the pixel dimensions the intrinsics correspond to. If you resize the image, scale the intrinsics by the same factor.
* **`focalUncertainty`** / **`focalUncertaintyRatio`**: the estimate's uncertainty in pixels and as a fraction of `fx`. Lower is more confident.
* **`distortion`**: present only when a distortion model is requested and coefficients are returned; `null` for `pinhole`.

{% hint style="warning" %}
This is a **prior/estimate**, not a substitute for a full calibration target. Treat the result as a good starting point that a downstream process can refine.
{% endhint %}

{% openapi src="/files/c9LGlr2GJL4BlKVHq2ap" path="/vps/camera-intrinsics" method="post" %}
[camera-intrinsics.yaml](https://3163433004-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FokTDI7QVY04Zvb1pQ8Ry%2Fuploads%2Fgit-blob-8467843fe3cd7dd90e313d3028ea732e325fb6bb%2Fcamera-intrinsics.yaml?alt=media)
{% endopenapi %}


---

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