Node-Guide

Writes the upstream image to a file; the format is inferred from the extension.

Second-derivative operator: isotropic edge/texture response, used for sharpening and edge detection.

Median filter: takes the median in the window — extremely effective on salt-and-pepper noise, edge-preserving.

Open/close/gradient/top-hat/black-hat: the composed morphology operations in one node.

Gaussian blur + halved size: anti-aliased downsampling.

Upscale ×2 then blur: the pyramid inverse.

Scharr operator: more rotationally accurate than Sobel at the 3× kernel size.

Two 1D kernels applied in sequence (horizontal then vertical) — the fast filter2d for big kernels.

Sobel gradient with selectable dx/dy orders — the basic edge-detection building block.

Averaged squared pixel values over the window — a building block for local energy/variance.