# 📐 L2 Spec — Fundus Imaging (retinal photography) Mismatch-Only Spec
**ID:** `L2-049-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-049`](/artifact/l1/L1-049)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41552979
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 1024 |
| W | px | 1024 |
| Snr db | dB | 15.0 – 45.0 |
| Fov deg | deg | 20 – 60 |
| Pupil mm | mm | 2.0 – 8.0 |
| Misalignment | — | 0.0 – 0.5 |
| Reflex artifact | — | 0.0 – 0.3 |
| Cataract opacity | — | 0.0 – 0.5 |
| Pupil size variation | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
25.0 + 0.3 * SNR_dB - 10.0 * cataract_opacity - 6.0 * reflex_artifact
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`d7f4793f17f0d5938f40c5456dedad849b3bd9b9896f41d883947ecd1969fbe9`
## 5. On-chain Registration
- **Chain hash:** `0x794451b7852104dd7cbc4ea02d1b8ac17eb4596ce61802bea65cb38dc0b9a044`
- **Chain tx hash:** `0x808c9e8bb164ade504b0202e60cb24a71c5c3712c65f77374b03fd3d0b59d216`
- **Chain block:** `41552979`
---
## File Mapping
This bundle consists of: `L2-049-001.md`, `L2-049-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-049-001.md` | Source of truth — edit this | Human or LLM |
| `L2-049-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-049-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._