Thai PDF OCR Extractor

The Problem: The "Thai Vowel" Nightmare

The Solution: A Modular Multi-Engine Pipeline

We didn't just build a script; we built a selector. Realizing that no single OCR engine is perfect for every scenario, we architected a solution that allows users to choose their "weapon" based on the document type.

Figure: Thai OCR Hero

Technical Deep Dive

1. Engine 1: The Local Workhorse (EasyOCR)

For privacy-centric or offline tasks, we integrated EasyOCR.

Figure: EasyOCR Framework

• Pros: Runs entirely locally, free, supports 80+ languages.
• Optimization: We implemented a pre-processing pipeline using OpenCV to de-noise and binarize scanned documents before identifying text regions. This significantly boosts accuracy on older, grainy scans.

2. Engine 2: The Cloud Specialist (Typhoon OCR)

For documents requiring high-fidelity structure preservation (like forms or academic papers), we integrated the Typhoon OCR API.

Figure: Typhoon OCR

• Capability: Typhoon is specifically fine-tuned for the Thai language. It excels at recognizing specific Thai fonts (like TH Sarabun New) often used in official documents.
• Integration: Built a robust wrapper to handle API rate limits and batched requests for multi-page documents.

3. PDF-to-Image Pipeline

• Native PDFs: Converted to high-DPI images (300 DPI) using pdf2image to ensure crisp character edges for the OCR model.
• Stitching: Automated logic to stitch extracted text back into page-ordered text files.

Stack

• Language: Python
• Core: EasyOCR, Typhoon API
• Processing: OpenCV, pdf2image, Poppler
• Format: PDF -> TXT