Optimizing OCR Performance on Mobile: From 5 Seconds to Under 1 Second

OCR on mobile needs to be fast. Users expect results in under 2 seconds. When I started building Screen Translator , our initial OCR pipeline took 4-5 seconds per screen capture. That's an eternity when you're trying to read a game menu or translate a chat message in real time. Here's how we got it down to under 1 second on modern devices. The Bottlenecks Before optimizing, we profiled the pipeline: Screen capture : ~200ms (MediaProjection API) Image preprocessing : ~800ms 😱 OCR inference : ~2500ms 😱😱 Translation API call : ~500ms UI rendering : ~100ms Total: ~4100ms. Steps 2 and 3 were the obvious targets. Optimization 1: Smart Image Downscaling The biggest win came from not feeding full-resolution screenshots to the OCR engine. fun optimizeForOCR ( bitmap : Bitmap ): Bitmap { val maxDimension = 1280 // Sweet spot for accuracy vs speed val scale = minOf ( maxDimension . toFloat () / bitmap . width , maxDimension . toFloat () / bitmap . height , 1f // Don't upscale ) if ( scale >= 1f )