ray
94 lines
4.4 KiB
Markdown
94 lines
4.4 KiB
Markdown
---
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name: ocr-data-extraction
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description: "Extract structured data (names, phones, VINs, dates) from OCR'd text using rule-based regex parsing — no AI/API needed."
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version: 1.0.0
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author: Hermes Agent
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license: MIT
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metadata:
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hermes:
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tags: [OCR, parsing, regex, data-extraction, screenshots, browser, Tesseract]
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related_skills: [ocr-and-documents]
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---
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# OCR → Structured Data Extraction (Rule-Based)
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Extract structured fields from OCR'd text using pure regex — no API keys, no network calls, no AI. Runs entirely on CPU, either in-browser (Tesseract.js CDN) or server-side (Tesseract CLI).
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**When to use this approach vs AI/API:**
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- Data follows predictable patterns (phones, VINs, dates, names)
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- Latency matters (instant vs 1-3s API call)
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- Cost matters (free vs per-call billing)
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- Privacy matters (data stays local)
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- User explicitly prefers CPU-based — **honor this signal immediately**
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## Quick Start (Browser)
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```html
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<script src="https://cdn.jsdelivr.net/npm/tesseract.js@5/dist/tesseract.min.js"></script>
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```
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Then call `Tesseract.recognize(file, 'eng', { logger })` to get text, then run the parser.
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## Parser Architecture
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The parser uses **layered extraction** in this order:
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### 1. Block Splitting
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Split OCR text on blank lines first. If that fails, detect table-like structures (consistent word counts across lines).
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### 2. Structured Field Extraction (per block)
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Extract and REMOVE these from the text first (order matters — early extraction simplifies later parsing):
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```
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Phone: /\(?\d{3}\)?[\s.\-]*\d{3}[\s.\-]*\d{4}/
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VIN: /\b[A-HJ-NPR-Z0-9OIQ]{17}\b/i ← lenient: accepts O→0, I→1, Q→0
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Date: YYYY-MM-DD, MM/DD/YYYY, "Jan 15, 2024"
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Time: 9:00 AM, 1:30PM, 14:00, 8am
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Duration: /\b(\d+)\s*(?:min|minutes?|hrs?|hours?)\b/i
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```
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**OCR VIN tolerance**: Tesseract commonly confuses `0→O`, `1→I`. Accept O/I/Q in the regex, then normalize:
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```js
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function fixVin(v) { return v.toUpperCase().replace(/O/g,'0').replace(/I/g,'1').replace(/Q/g,'0'); }
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```
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### 3. Remaining Text → Name / Vehicle / Service
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After removing structured fields, split remaining text on multi-spaces (preserves column structure). Then:
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- **Name**: first part, or consecutive capitalized words without digits
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- **Vehicle**: part containing year pattern (`19xx`/`20xx`) or known makes (`ford|toyota|honda|bmw|...`)
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- **Service**: everything else
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### 4. Advisor + RO Code Stripping
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If the source has `AdvisorName [RO_CODE]` prefixes, strip them:
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```js
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var m = part.match(/^([A-Z][a-z]+)\s+(\[[^\]]+\])\s+(.*)/);
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if (m) { roCode = m[2]; return m[3]; } // return service, save RO as note
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```
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### 5. Multi-Appointment Boundary Detection
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When multiple appointments appear without blank-line separation, detect boundaries by:
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- Find the next phone/VIN in the remaining text
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- **Walk back** to the nearest multi-space gap or capitalized name before it
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- Split there — text before goes to current appointment, text after recurses
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- Regex for gap walk-back: `/\s{2,}(?=\S+(?:\s+\S+){0,1}\s*$)/`
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- Fallback (no gap): detect last 1-2 capitalized words before phone: `/([A-Z][A-Za-z]+(?:\s+\S+){0,1})\s*$/`
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### 6. Header/Noise Stripping
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- Separator lines: `/^[\-–=_*#]{3,}$/` → remove
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- Short all-caps headers: `< 25 chars, all uppercase letters/spaces` → remove
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- Table header row: contains `name|phone|date|time|service|vehicle|vin` → skip first line
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- Known header words: `schedule|appointments|roster|calendar|upcoming` → filter from parts
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## Pitfalls
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- **Don't collapse whitespace before splitting**: Split on `\s{2,}` FIRST, then clean each part. If you collapse to single spaces first, multi-space splitting silently breaks.
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- **Trailing space before boundary breaks regex**: Phone/VIN markers are often preceded by a space in the OCR. Trim or use `\s*$` in lookahead regexes.
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- **"O" in VIN ≠ letter O**: Always use lenient VIN regex and normalize. OCR will turn zeros into O's.
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- **Advisor names vs customer names**: In shop management systems, "Word [CODE]" is advisor+RO, not customer. Strip it.
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- **Block recursion can re-include old text**: When recursing, pass only the text AFTER the boundary split point, not the full remaining `b` variable.
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- **Table detection false positives**: Only use line-by-line table parsing when lines have consistent word counts (≤3 word difference from average). Exclude header line before checking consistency.
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## Reference File
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See `references/parser-patterns.md` for the full extraction regex catalog and test cases.
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