VFX Atlas
M 027 / 18301 Edge & Featuresalgorithm output

Frangi Ridge Filter

edge & features

Typeface · Martian Mono

Atlas demonstration: the free source photo and the computed Frangi Ridge Filter. A dense cluster of heart-shaped leaves overlaps in a natural arrangement. The fine veins and edges of the foliage are rendered as brilliant white tubular networks against a dark background.
Atlas demonstration: the free source photo and the computed Frangi Ridge Filter. A dense cluster of heart-shaped leaves overlaps in a natural arrangement. The fine veins and edges of the foliage are rendered as brilliant white tubular networks against a dark background.Image: Amith Nair a_myth · CC0 (via Wikimedia Commons), processed for the AtlasView source ↗

Prompt

Transform this image into a Frangi Ridge Filter response map, emphasizing existing thin, elongated, branching structures as luminous white ridges against black. Vary ridge brightness with structural strength, retain multiple widths, and suppress flat surfaces, isolated rounded blobs, and unrelated texture. Keep the original subject and composition.

Paste it into LetzAI with your own image to apply the effect ↗

Identify

Thin, branching structures stand out in a ridge response map, while flat areas and rounded blobs are subdued.

Principle

The filter compares eigenvalues1 of Hessian matrices2 across several scales to measure how strongly each region resembles a tube. It favors elongated ridges over flat areas and blobs, selecting bright or dark structures according to polarity settings.

Try it out

Vary the scale range to emphasize fine threads or thicker branches.

Classification

Calculated image processing result.

Further examples · 9 images

Frangi Ridge Filter, applied to “Hands on a guitar neck (Unsplash)”
02 Frangi Ridge Filter, applied to “Hands on a guitar neck (Unsplash)”A musician's hands are positioned over the headstock and strings of a bass guitar. The linear geometry of the strings and the curved silhouettes of the tuning pegs are transformed into luminous neon-like contours.Derek Truninger dtruninger (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “Hamburg puppy (Unsplash)”
03 Frangi Ridge Filter, applied to “Hamburg puppy (Unsplash)”A shaggy-haired dog sits facing the viewer in an outdoor setting. The individual strands of fur and the animal's distinct outline are emphasized through intense, thread-like luminance.Eddy Lackmann eddyray (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “Cecile Vedemil 2015 (Unsplash)”
04 Frangi Ridge Filter, applied to “Cecile Vedemil 2015 (Unsplash)”A pair of cupped hands holds a cluster of fallen leaves. The algorithm isolates the delicate veins and serrated edges of the foliage, rendering them as a network of intricate, tubular vessels.Cecile Vedemil cvedemil (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “Caught In The Middle (Unsplash)”
05 Frangi Ridge Filter, applied to “Caught In The Middle (Unsplash)”A pedestrian walks past a sapling and a large industrial door. The thin, branching limbs of the young tree are perfectly emphasized as luminous white paths, showcasing the mathematical preference for elongated structures.Tuce dsamps (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “McWay Falls 1 (Unsplash)”
06 Frangi Ridge Filter, applied to “McWay Falls 1 (Unsplash)”A rugged coastline meets the sea under a dark sky. The jagged edges of the cliffs and the surface ripples of the water are isolated into a complex web of thin white highlights.Denys Nevozhai dnevozhai (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “Castelluccio, Italy (Unsplash)”
07 Frangi Ridge Filter, applied to “Castelluccio, Italy (Unsplash)”A herd of cattle grazes in a field before a looming mountain range. The silhouettes of the livestock and the grassy textures are translated into delicate, glowing filigree.marco forno marco4no (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “Monochrome guitar player (Unsplash)”
08 Frangi Ridge Filter, applied to “Monochrome guitar player (Unsplash)”A musician is captured mid-performance while playing a guitar. The computational process highlights the guitar strings and the player's silhouette as glowing white skeletal lines against the darkness.Markus Spiske markusspiske (photo); processed for the Atlas · CC0 · Wikimedia Commons
Frangi Ridge Filter, applied to “Green mountains over clouds (Unsplash)”
09 Frangi Ridge Filter, applied to “Green mountains over clouds (Unsplash)”The sun begins to rise or set over a series of rolling mountain ridges. While the peaks are defined by bright contours, the interior slopes are filled with a dense, chaotic web of response to the rocky terrain.Ricky Paulus rickypaulus (photo); processed for the Atlas · CC0 · Wikimedia Commons

Sources