NerdTrack vs Lens Pattern

NerdTrack records your location in a CSV file on your phone. No other data is collected and no data ever leaves your device. Full source is available at https://nerdtrack.org There is no interactive UI. Just grant location permissions, and it will log in the background. To stop logging, remove location permissions or uninstall app. The app uses the SignificantLocation and CLVisit APIs. The accuracy is low but it has very low battery usage. To get your log, open the Files app, and look for locations.csv in the Nerd Track folder. A config file will be created in the app's documents folder the first time it runs. Edit that file to change logging frequency or minimal distance. Force-stop and restart app to reload config. By default, the app records location: - Every 15 minutes, if you have moved more than 300 meters The CSV logs timestamps in the unix epoch format. Use 'dateconv -i %s' to convert it to something more human-readable. Some helper scripts are available at https://nerdtrack.org

Grid Professional Test Patterns for Camera Calibration Turn your iPad, iPhone, or Apple TV into a precision test pattern generator for camera and lens analysis. Lens Pattern displays pixel-accurate test charts directly on your device screen — no printed charts, no extra hardware. Perfect for camera calibration, lens quality testing, color grading verification, and production monitoring. INCLUDED TEST PATTERNS: Markers & Calibration • Grid Tags — AprilTag marker grid with adjustable tag size and start ID, ideal for camera calibration and spatial tracking Color & Exposure • SMPTE Bars — Standard SMPTE EG-1-1990 color bars • SMPTE 303M — HD color bars with PLUGE and Y-ramp zones • EBU Bars — EBU Tech 3325 color bars (75% and 100%) • ColorChecker — Classic 24-patch color reference chart • Color Scales — R/G/B/C/M/Y/W gradient ramps with percentage markers • Clipping — Shadow and highlight clipping test (1% steps) with stepped ramp • Grayscale — 21-step grayscale ramp with percentage labels Geometry & Focus • Crosshatch — Grid pattern for distortion analysis • Checkerboard — Black/white checkerboard for resolution testing • Caro — Diamond pattern (45° rotated checkerboard) • Dot Grid — Uniform dot array for distortion measurement • Siemens Star — Resolution target for sharpness evaluation • Focus Chart — Comprehensive focus and resolution target Timing & Animation • Motion Test — Moving bars for rolling shutter and motion blur analysis • Timecode — Real-time HH:MM:SS:FF display at 60fps • Flicker — Adjustable frequency flicker (0.5–30 Hz) KEY FEATURES: • Full-screen, pixel-perfect rendering on any screen size • Physical dimensions in millimeters displayed on iOS devices