Menu: Functions - setiastro/setiastrosuitepro GitHub Wiki

Functions Menu

Below is a quick-reference for every item under Functions—what it does, typical use, and notable behaviors. Items marked (dialog) open a tool window; others run immediately.

Inspection & Prep

  • Histogram… (dialog) View histogram and basic stats for the active image. Use to gauge clipping, balance, and stretch progress.

  • Crop… (dialog) Interactive crop/rotate with on-canvas handles. Confirms to apply to the active document.

  • Remove Pedestal Subtracts the per-channel minimum to remove black-level offsets. Ctrl+P. Tip: Click = apply to active view; Alt+Drag the action onto a view = headless apply.

Stretch

2.1. Statistical Stretch… (dialog)

Analytic, target-median stretch. Uses the same midtones transfer as Star Stretch and solves it in closed form to reach a chosen target median $T'$ from the current median $T$.

Mapping

f_a(T) = \frac{3^{a}\,T}{\left(3^{a}-1\right)T + 1}

Solve for the “amount” $a$ given $T \rightarrow T'$ (with $T,T'\in(0,1)$)

a = \frac{\log\!\Big(\dfrac{T'}{1-T'} \cdot \dfrac{1-T}{T}\Big)}{\log 3}

Workflow

  1. Set Black Point
  2. Stretch to Target Median using $f_a$
  3. Normalize White Point
  4. Optional Curve boost

Note: This is not arcsinh; it’s a closed-form midtones transfer aimed precisely at a target median.

2.2. Star Stretch… (dialog)

Midtones-transfer stretch with analytic continuation, tuned to protect star cores and preserve color.

Tone curve (same family as above)

f_a(x) = \frac{3^{a}\,x}{\left(3^{a}-1\right)x + 1}, \quad x\in[0,1]

Here $a$ is a continuous strength—the analytical continuation of repeatedly applying the standard midtones operator (again, not arcsinh). It’s monotonic, compresses highlights smoothly, and gently lifts midtones.

Extras

  • SCNR (green suppression) toggle.
  • Color Boost applies a mild saturation spline (peaks near mid-tones); approximately: $[0,;0.4,s],\ [0.5,;0.7,s],\ [1,;0.4,s]$ where $s$ is the user satAmount.

Background & Color

  • ABE… (Automatic Background Extraction) (dialog) Builds a background model from samples; removes gradients.

  • Remove Gradient (GraXpert)… (dialog/integration) Calls GraXpert on the active image to perform background extraction.

  • Background Neutralization… (dialog) Neutralize color cast in the background using a sampled region.

  • White Balance… (dialog) Star-based, manual, or auto white balance options.

  • Spectral Flux Color Calibration (SFCC)… (dialog) Photometry-informed calibration (Pickles library + filters + sensor QE).

  • Remove Green… (dialog) SCNR-style green suppression to tame chroma casts.

Matching & Convolution

  • Linear Fit… (dialog) — Match levels between images (choose reference/target). Ctrl+L
  • Convolution / Deconvolution… (dialog) — Blur/sharpen with PSF controls; deconvolution modes included.

Channels & Luminance

  • Extract Luminance — New mono document from Rec.709 luminance of the active RGB image.
  • Recombine Luminance… (dialog) — Replace the active image’s luminance from another view (L-RGB workflow).
  • RGB Extract — Split into three mono docs (R, G, B).
  • RGB Combination… (dialog) — Combine three mono images into RGB.

Detail, Structure & Local Contrast

  • WaveScale HDR… (dialog) — Wave-scale HDR with luminance-masked starlet.
  • WaveScale Dark Enhancer… (dialog) — Enhances faint/dark structures using wavelet-guided masking.
  • CLAHE… (dialog) — Contrast Limited Adaptive Histogram Equalization for local contrast without over-amplifying noise.
  • Morphological Operations… (dialog) — Erode / Dilate / Open / Close with tunable kernels.

Stars

  • Remove Stars… (dialog/integration) — Run star-removal on the active image (starless and/or stars-only output).
  • Add Stars… (dialog) — Blend a starless view with a stars-only view to reunite stars with tuned opacity/color.
  • Halo-B-Gon… (dialog) — Targeted star-halo reduction.

Cosmetic, Math & Retouch

  • Blemish Blaster… (dialog) — Interactive heal/clone-style cleanup.
  • Pixel Math… (dialog) — Evaluate expressions referencing open view names (per-pixel math & compositing).
  • Signature / Insert… (dialog) — Add signatures/overlays (watermarks, labels) and bake them into the active image.

Notes

  • All tools act on the active document/view unless the dialog offers multi-view selection.
  • Dialogs create history steps; Undo/Redo is supported.
  • Several actions (e.g., Remove Pedestal) support headless drag-and-drop from the shortcuts canvas onto a specific view.

Tip for the wiki: GitHub renders math with $…$, $$…$$, or fenced ```math blocks; the fenced form used above avoids delimiter edge cases and usually looks best in wikis. ([GitHub Docs]1)