semper
Parameters
Every analysis setting, its range, and when to move it. The defaults are good starting points — you rarely need to change more than the subset and strain window.
Quote VSG = (strain window − 1) × step + 1 with any strain result — it is the distance one strain value covers. See VSG in the glossary.
| Parameter | Range | Default | Raise when | Lower when |
|---|---|---|---|---|
| Subset | 15–121, odd | Recommended | Speckle is weak; correlation fails | You need resolution across a sharp gradient |
| Step | 1–30 | 5 | Runtime matters | You need a denser field |
| Strain window | 5–101, odd | 15 | Strain is noisy | Detail is being smoothed away |
| Kernel | 4×4 / 6×6 | 4×4 Bicubic | Studying interpolation bias | — |
| Max frames | 10–150 | 50 | Long sequences | Runs are killed for memory |
| Sweep subset range | 15–121, odd | Around recommended | — | — |
| Sweep strain window range | 5–101, odd | 5–101 | Strain is noisy | Detail is being smoothed away |
| Step denominator | 2–9 | — | Denser correlation | Faster runs |
| Samples | 1–8 per axis | 3 | Finer detail | Runtime is the product |
Where the recommended subset comes from: the app looks at your reference image and picks a subset size big enough to match reliably — larger where the speckle is weak. Once you drag the slider yourself it stops tracking the image; Reset brings the recommendation back.