One measurement principle. Many physical scales.
A shirt-pocket case study showing how structured illumination, moiré amplification, multi-angle sizing, and computational diagnostics can find and measure subtle textile features across a large field.
The mathematics scales. The instrument must be calibrated.
Moiré methods compare structured carriers and convert small differences in geometry, displacement, phase, or pitch into larger beat patterns. Those relationships are not confined to one object size, so the same measurement logic can operate across textile, component, microstructure, and nanoscale applications.
What changes is the physical implementation: wavelength, grating or carrier pitch, numerical aperture, camera sampling, working distance, field of view, contrast, environmental stability, and the calibration reference.
Three compact features retained inside the defined region of interest.
The analysis preserved the complete shirt view, rejected candidates outside the pocket, and estimated each retained feature using six directional calipers.
Values are image-derived apparent diameters at a working scale of 0.214 mm/pixel. They are not yet traceable physical hole-edge diameters.
Keep the region, reject false positives, report uncertainty.
The case separates detection from interpretation. Features outside the pocket are explicitly rejected, directional variability is reported rather than hidden, and the full frame remains available for human review.
- Pocket-only ROI
- Off-pocket rejection
- Six caliper angles
- Mean and spread
- Full-frame context
- Explicit claim limits
Carrier + interaction + phase = a reusable measurement pattern.
The same conceptual structure appears across applications even as its physical parameters change.
Create a known spatial reference.
Project or introduce a calibrated fringe, grating, illumination structure, or reference field appropriate to the working scale.
Let geometry modulate the carrier.
Surface shape, displacement, refractive behavior, material boundaries, or defects change the observed amplitude and phase.
Recover useful measurements.
Fourier filtering, sideband analysis, phase unwrapping, segmentation, and calibrated models convert the pattern into decisions.
Separate phase evidence from depth claims.
The fringe image was compared with an ideal 3 mm carrier reference. The close carrier-period agreement supports the phase/modulation diagnostic path, while the absence of a matched reference plane prevents a calibrated 3D-depth claim.
Move from a diagnostic result to traceable textile metrology.
The next capture should isolate illumination effects, establish a matched reference plane, and measure detection performance across known defects.
No-fringe control
Capture the same shirt at identical geometry and exposure without the projected carrier.
Matched flat reference
Acquire reference geometry at the shirt plane for calibrated phase interpretation.
Traceable scale
Validate 0.214 mm/pixel with a target located in the same measurement plane.
Performance metrics
Report sensitivity, false positives per area, localization error, repeatability, and confidence.
Test defects, seams, distortion, and surface variation across the complete garment.
A focused pilot can define the defect classes, capture geometry, acceptance thresholds, throughput target, and traceable reference needed for a production-quality inspection workflow.