BUILT-IN MATHEMATICA SYMBOL

# RidgeFilter

RidgeFilter[image]
computes a measure for the presence of a ridge for each pixel in image.

RidgeFilter[image, ]
uses the specified ridge scale .

## Details and OptionsDetails and Options

• RidgeFilter computes the main principal curvature at each pixel.
• The main principal curvature orthogonal to a ridge is given by the main negative eigenvalue of the Hessian matrix.
• In RidgeFilter[image, ], is the scale of the ridges that is used to compute the derivatives in the Hessian.
• RidgeFilter[image] is equivalent to RidgeFilter[image, 1].
• RidgeFilter works with arbitrary grayscale or multichannel images, operating separately on each channel.
• RidgeFilter[image, ...] returns a real image of the same dimensions as image.
• RidgeFilter[array] computes the ridges in a two-dimensional array.
• RidgeFilter supports the following options to compute the Hessian matrix and the main principal curvature:
• Possible settings for the InterpolationOrder option are 3, 5, 7, or 9.
• The Padding option accepts the settings , , , , or a numeric value. A list of two settings can specify different paddings for each dimension.

## ExamplesExamplesopen allclose all

### Basic Examples (3)Basic Examples (3)

Detect lines of a given width in a noisy image with uneven brightness:

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Find the mountain ridges in a terrain elevation raster:

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Enhance the strokes of handwritten characters:

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