How to Handle Vertical Japanese Text in Android OCR

Japanese text can be written vertically (tategaki, 縦書き) — top-to-bottom, right-to-left columns. This is the standard layout in manga, many games, and traditional Japanese documents. If you're building an OCR-based translation tool for Android, handling vertical text is one of the trickiest challenges you'll face. The Problem Most OCR engines are optimized for horizontal left-to-right text. When you feed them a manga page with vertical Japanese text, you get: Garbled character order Merged text from adjacent columns Missing characters at column boundaries Completely wrong reading direction Detection Strategies 1. Aspect Ratio Analysis Vertical text blocks tend to be taller than wide. If a detected text region has a height-to-width ratio > 2:1, it's likely vertical text. 2. Character Spacing Patterns In vertical text, characters are stacked with consistent vertical spacing. Analyze the spatial distribution of detected characters — if they cluster along vertical axes, rotate the region 90