Input Image
RGB Data

Grayscale Conversion
- Convert RGB → Grayscale
- Apply luminance formula: I = 0.2997G + 1.114B
- Preserve structural details

Contrast Enhancement
- Apply contrast multiplier (2.0)
- Improve text/background separation

Sharpening Filter
- Apply sharpening kernel
- Improve clarity for OCR

Replace with fallback caption

Else use extracted OCR text

If token count < 3