perf(scanner): three high-impact speed optimizations #156

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rstillwell merged 1 commit from perf/scanner-speed-optimizations into main

2026-09-01 18:18:14 -04:00

rstillwell commented

2026-09-01 18:17:59 -04:00

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Summary

Three targeted optimizations to make the card scanner feel faster on mobile, based on profiling the identify pipeline.

1. Non-blocking scan capture upload

File: lib/use-scanner-identification.js

emitScannedCard() previously awaited uploadScanCapture() before calling onCardScanned(). This blocked the result display for ~500ms+ (MinIO roundtrip). Now the card result is shown immediately and the upload fires in the background.

Impact: ~500ms faster result display for every scanned card.

2. Parallel OCR workers

File: lib/ocr-worker.js

recognizeCardFields() ran two sequential worker.recognize() calls (name strip + number strip) on a single Tesseract worker — the number strip always waited for the name strip to finish. Now two independent workers run in parallel via Promise.all().

Also cleaned up terminateOcrWorker() to properly tear down both workers.

Impact: Layer 1 OCR time cut ~50% on mobile (from ~1.5-3s to ~0.7-1.5s).

3. Faster pre-verification timing

File: lib/scanner-card-detection.js

Constant	Before	After
`VERIFICATION_INTERVAL_MS`	1000ms	500ms
`MIN_FIRST_SEEN_MS_FOR_VERIFY`	800ms	500ms

Cards now reach the verification pipeline ~300ms faster after first detection.

Impact: ~300ms reduction in auto-detect-to-identify latency.

Test results

All 58 scanner tests pass (2.20s). No behavioral changes to identification logic.

## Summary Three targeted optimizations to make the card scanner feel faster on mobile, based on profiling the identify pipeline. --- ### 1. Non-blocking scan capture upload **File:** `lib/use-scanner-identification.js` `emitScannedCard()` previously `await`ed `uploadScanCapture()` before calling `onCardScanned()`. This blocked the result display for ~500ms+ (MinIO roundtrip). Now the card result is shown immediately and the upload fires in the background. **Impact:** ~500ms faster result display for every scanned card. --- ### 2. Parallel OCR workers **File:** `lib/ocr-worker.js` `recognizeCardFields()` ran two sequential `worker.recognize()` calls (name strip + number strip) on a single Tesseract worker — the number strip always waited for the name strip to finish. Now two independent workers run in parallel via `Promise.all()`. Also cleaned up `terminateOcrWorker()` to properly tear down both workers. **Impact:** Layer 1 OCR time cut ~50% on mobile (from ~1.5-3s to ~0.7-1.5s). --- ### 3. Faster pre-verification timing **File:** `lib/scanner-card-detection.js` | Constant | Before | After | |---|---|---| | `VERIFICATION_INTERVAL_MS` | 1000ms | 500ms | | `MIN_FIRST_SEEN_MS_FOR_VERIFY` | 800ms | 500ms | Cards now reach the verification pipeline ~300ms faster after first detection. **Impact:** ~300ms reduction in auto-detect-to-identify latency. --- ### Test results All 58 scanner tests pass (2.20s). No behavioral changes to identification logic.

rstillwell added 1 commit 2026-09-01 18:17:59 -04:00

perf(scanner): three high-impact speed optimizations

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04504903bf

1. Non-blocking scan capture upload (emitScannedCard)
   - Card result shows immediately; upload fires in background
   - Removes ~500ms blocking S3/MinIO roundtrip from the result path

2. Parallel OCR workers for name + number strips (ocr-worker)
   - Two independent Tesseract workers run simultaneously
   - Cuts Layer 1 OCR time ~50% on mobile (name + number in parallel)
   - terminateOcrWorker cleans up both workers on teardown

3. Faster pre-verification timing (scanner-card-detection)
   - VERIFICATION_INTERVAL_MS: 1000 → 500ms
   - MIN_FIRST_SEEN_MS_FOR_VERIFY: 800 → 500ms
   - Net ~300ms faster from first detection to verification start

All 58 scanner tests pass (2.20s).