OCR Accuracy Benchmarks & Testing Methodology
We believe in complete transparency. We publish our empirical test results across different document categories, failure rates, testing protocols, and known limitations so users and developers know exactly what to expect.
98.4%
Printed Text
High-contrast PDFs & books
88.2%
Neat Handwriting
Student lecture notes & diaries
73.6%
Doctor Slips (Raw)
86.1% with clinical entity linking
97.1%
Indian ID Cards
Aadhaar, PAN & Passport MRZ
1. Benchmark Results by Document Category
Evaluated against an empirical test set of 1,950 real-world documents collected between May 2026 and October 2026. Accuracy is measured using industry-standard Character Error Rate (CER) and Word Error Rate (WER) against double-blinded human transcriptions.
| Document Category | Sample Size | Char Accuracy (1-CER) | Word Accuracy (1-WER) | Primary Failure Mode |
|---|---|---|---|---|
| Clean Printed English Books, invoices, digital PDFs, legal contracts | 500 docs | 98.4% | 96.8% | Obscure font serifs, tiny punctuation dots |
| Bilingual Printed Documents (Hindi + English) Government gazettes, Indian university mark sheets | 300 docs | 94.7% | 91.2% | Devanagari conjunct consonants (halant, matras) |
| Student Lecture Notes (Neat Handwriting) Ruled paper, ballpoint/gel pens, clear lighting | 250 pages | 88.2% | 83.5% | Connected cursive loops (e.g. 'u' vs 'v', 'cl' vs 'd') |
| Indian Medical Prescriptions (OPD Slips) Cursive shorthand, doctor abbreviations (BD, TDS, SOS) | 350 slips | 73.6% (Raw) 86.1% w/ MedDict | 68.2% (Raw) 82.4% w/ MedDict | Extreme abbreviation, overlapping scribbles, brand typos |
| Faded Paper & Carbon Copies Thermal billing receipts, faded hospital discharge notes | 150 docs | 64.2% (Raw) 82.5% w/ Enhancer | 59.8% (Raw) 78.1% w/ Enhancer | Faded ink contrast drop, background paper grain noise |
| Indian ID Cards & Passports Aadhaar QR/Masking, PAN Card, Passport MRZ Lines | 400 cards | 97.1% | 95.4% (99.8% MRZ) | Hologram glare, laminated plastic reflection |
2. Engine Architecture Comparison: Local WASM vs Cloud AI
DoctorDocs utilizes a dual-engine architecture to balance absolute privacy against recognition capabilities for challenging handwriting:
Local Engine (Tesseract.js WASM)
- Privacy: 100% In-Browser. 0 bytes transferred over the internet.
- Processing Speed: 800ms – 2.5s per standard page.
- Offline Support: Works fully offline once cached.
- Best For: Clean printed books, bank statements, high-contrast receipts.
- Limitations: Struggles with connected cursive handwriting and faded ink.
Cloud AI Engine (Gemini 1.5 Flash)
- Privacy: Encrypted in transit (TLS 1.3). Zero retention for model training.
- Processing Speed: 1.5s – 3.2s per page.
- Offline Support: Requires active internet connection.
- Best For: Difficult doctor prescriptions, complex cursive notes, lab reports.
- Limitations: Governed by fair-use API quotas (1 free scan per session; unlimited on Pro).
3. Documented Failure Modes & Edge Cases
1. Severe Motion Blur & Angled Distortion
When images are captured at steep angles (>35 degrees) or with camera shake, character edge detection drops by up to 28%. We strongly recommend using our interactive document scanner camera tool, which detects document borders before snapping.
2. Carbon Paper Ink Bleed-Through
Carbon copies from clinic registers frequently have ink bleed from the reverse side. The local engine may interpret ghost shadows as text. Toggling our built-in Magic Enhancer boosts contrast thresholding and reduces false positive bleed artifacts.
3. Non-Standard Regional Medicine Brands
India has over 100,000 regional branded generic formulations. When a physician writes an uncommon local brand phonetically with cursive abbreviation, OCR cannot guarantee accurate transcription without human verification.
4. Methodology & Reproducibility
Our accuracy evaluation pipeline is open and verifiable:
- Ground Truth Formulation: Each test document is independently transcribed by two human operators. Discrepancies are reconciled by a third reviewer.
- Normalization: Whitespace, unicode quotes, and case variations are normalized before running Levenshtein edit distance calculations.
- CER & WER Metrics:CER = (Substitutions + Deletions + Insertions) / Total Reference Characters
Accuracy = 1 - CER (expressed as a percentage) - Hardware Consistency: Local WASM tests were executed on Chromium V8 (MacBook Air M2, 16GB RAM and Moto G Power Android phone). Cloud AI tests were routed through our stateless edge inference pipeline.
Help Us Improve Our Benchmarks
Found a document that failed recognition or produced an incorrect transcription? Share your feedback to help us refine our preprocessing and model cascades.