Photograph the fixed (reference) grating and the moving grating separately; the app overlays them.
No readings yet — analyze a pair of photos and save to begin a log.
Runs the Fourier phase-demodulation (linear) and matched-filtering (circular) methods entirely in your browser — photos are never uploaded, only the computed numeric reading is sent to the server to be stored in SQLite. Set the field of view by measuring a known reference length in the frame.