# ⚛  L1 Principle — Digital Image Correlation (DIC) for full-field strain

**ID:** `L1-123` · **Status:** ⊙ Testnet (genesis catalog)

> **🌐 Domain:** Industrial Inspection — *Full-field displacement and strain via speckle tracking*
> **🎯 Problem class:** linear inverse · **🧮 Solution space:** 2D displacement strain
> **📡 Carrier:** photon · **🌫 Noise:** gaussian
> **⚖ Difficulty (δ):** 3 · **⛓ Block:** 41554212

---

## 🧠 1. Introduction

**Digital Image Correlation (DIC) for full-field strain** is a **linear inverse problem** whose unknown lives in **2D displacement strain** space, within the **Full-field displacement and strain via speckle tracking** sub-domain of **Industrial Inspection**.

Measurements consist of photons collected by an optical detector via a **speckle correlation vision** sensing mechanism.

The forward operator applies, in order: L · speckle pattern operator; L · reference deformed operator; L · subset correlation operator; pixel-level spatial averaging on the detector.

Observations are corrupted by additive Gaussian noise. Existence of the recovered 2D displacement strain is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by the declared priors. Stability is well-conditioned (kappa_eff ~= 8); speckle_size_variation dominates the stability cliff; illumination_non_uniformity and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while mild Tikhonov or analytic inversion is sufficient at the nominal Omega point.

## ⚙ 2. Forward Model

Physical chain: **x** → L · speckle pattern → L · reference deformed → L · subset correlation → Spatial integration → **y** (detector).

```
y = ∫_A dA `L.subset_correlation` `L.reference_deformed` `L.speckle_pattern` x + n,    n ~ 𝒩(0, σ²)
```

**Measurement DAG:**

| Primitive | What it does |
|---|---|
| `L.speckle_pattern` | L · speckle pattern operator |
| `L.reference_deformed` | L · reference deformed operator |
| `L.subset_correlation` | L · subset correlation operator |
| `int.spatial` | Pixel-level spatial averaging on the detector |

## 🔬 3. Physics Fingerprint

| Property | Value |
|---|---|
| Domain | Industrial Inspection |
| Sub domain | Full-field displacement and strain via speckle tracking |
| Carrier | photon |
| Problem class | linear_inverse |
| Solution space | 2D_displacement_strain |
| Noise model | gaussian |
| Integration axis | spatial |
| Difficulty delta | 3 |
| L dag | 3 |

## 📡 4. Measurement Model

Existence of the recovered 2D displacement strain is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by the declared priors. Stability is well-conditioned (kappa_eff ~= 8); speckle_size_variation dominates the stability cliff; illumination_non_uniformity and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while mild Tikhonov or analytic inversion is sufficient at the nominal Omega point.

| Metric | Value |
|---|---|
| Metric | PSNR_dB |
| Secondary | SSIM |

## 📏 5. Operating Range (Ω)

**Center problem class:** `dic` · **Forward operator:** `dic_forward`

**Center point:**

| Parameter | Unit | Value |
|---|---|---|
| H | px | 2048 |
| W | px | 2048 |
| Snr db | dB | 30 |
| Pixel um | µm | 5 |
| Subset px | — | 21 |
| Out of plane motion | — | 0 |
| Speckle size variation | — | 0 |
| Illumination non uniformity | — | 0 |

**Allowed bounds:**

| Parameter | Unit | Range |
|---|---|---|
| H | px | 512 – 8192 |
| W | px | 512 – 8192 |
| Snr db | dB | 10.0 – 40.0 |
| Pixel um | µm | 1 – 50 |
| Subset px | — | 9 – 81 |
| Out of plane motion | — | 0.0 – 0.3 |
| Speckle size variation | — | 0.0 – 0.3 |
| Camera calibration error | — | 0.0 – 0.05 |
| Illumination non uniformity | — | 0.0 – 0.3 |

## 🎯 6. Tolerance (ε)

**Center tolerance:** 28.0

| Metric | Range |
|---|---|
| Psnr db | 5.0 – 40.0 |

## ⚖ 7. Hardness Function

Hardness scales as **`epsilon_fn`** on **PSNR_dB**, with κ = `160` and δ = `3`.

## 💾 8. Reference Dataset

- **primary** · weight 1.0 · IPFS _(not pinned yet)_

## 9. On-chain Registration

- **Chain hash:** `0xcc9ea5fa082850c8a7fe30e442fe5ee36bf50c63aa71727adff9a314cd0a253a`
- **Chain tx hash:** `0x5b2fb17cf3b6014ad7f6c25ce464cac90df202196229bcdbcfc23c021843fce1`
- **Chain block:** `41554212`

---

## File Mapping

This bundle consists of: `L1-123.md`, `L1-123.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L1-123.md` | Source of truth — edit this | Human or LLM |
| `L1-123.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 `L1-123`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._