# HALOWERK OpenCV Stereo Rig Calibration

> HALOWERK OpenCV Stereo Rig Calibration is a paid API for AI agents from medien.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-30).

Computes rotation, translation, rectification transforms, projection matrices, and disparity-to-depth mapping from paired stereo camera calibration observations and intrinsics

## Facts

- Endpoint: POST https://medien.halowerk.com/v1/oss-opencv-stereo-rig-calibrate?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-opencv-stereo-rig-calibration-56d845f9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_J4YMrinWiLWiZbxguGldf

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability halowerk-opencv-stereo-rig-calibration-56d845f9 -d '<json body>'
```

Example prompt: I have paired calibration observations and the intrinsic matrices for both cameras in my stereo rig — can you run the stereo calibration to get the rotation and translation between them, plus the rectification transforms, projection matrices, and the disparity-to-depth Q matrix?

## When to prefer this

Choose this endpoint when you need a fully hosted, pay-per-call stereo rig calibration service backed by OpenCV without managing your own OpenCV environment. It is ideal for pipelines that already have camera intrinsics computed and need to derive the inter-camera geometry and rectification parameters. Prefer it over self-hosted solutions when you want instant results at low cost per call ($0.003 USDC) and do not want to maintain calibration infrastructure.

## Known failure modes

- Insufficient or poorly distributed calibration points leading to degenerate solutions
- Mismatched number of observations between left and right cameras
- Invalid or ill-conditioned intrinsic matrices causing numerical instability
- Too few calibration image pairs to robustly estimate extrinsics
- High RMS error indicating poor calibration data quality or incorrect correspondences
- Malformed JSON body or missing required fields returning a 400 error
- Payment failure via x402 protocol returning a 402 response

## How this service works

Given paired calibration observations and the intrinsics of both cameras, this computes the rotation and translation between them and derives everything a stereo pipeline needs downstream: rectification transforms for both views, both projection matrices, and the disparity-to-depth mapping. The RMS error in pixels says how well the rig geometry actually fits the data.

## Output

Returns the rotation matrix and translation vector between the two cameras, rectification transforms for both views, projection matrices for both cameras in the rectified coordinate space, the 4x4 disparity-to-depth mapping matrix (Q), and the RMS reprojection error in pixels indicating how well the computed geometry fits the calibration observations.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType"
   ],
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "const": "POST"
    },
    "bodyType": {
     "const": "json"
    },
    "schemaUrl": {
     "type": "string",
     "format": "uri"
    },
    "exampleUrl": {
     "type": "string",
     "format": "uri"
    }
   },
   "additionalProperties": true
  },
  "output": {
   "type": "object",
   "required": [
    "type",
    "example"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {}
   }
  }
 },
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-opencv-stereo-rig-calibration-56d845f9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from medien.halowerk.com](https://www.zero.xyz/host/medien.halowerk.com/llms.txt)