# superpixels3

3-D superpixel oversegmentation of 3-D image

## Description

`[`

computes superpixels of image `L`

,`NumLabels`

]
= superpixels3(`A`

,`N`

,`Name,Value`

)`A`

using
name-value arguments to control aspects of the segmentation.

## Examples

## Input Arguments

## Output Arguments

## Algorithms

The algorithm used in `superpixels3`

is a modified version of the Simple
Linear Iterative Clustering (SLIC) algorithm used by `superpixels`

. At a high
level, it creates cluster centers and then iteratively alternates between
assigning pixels to the closest cluster center and updating the locations of
the cluster centers. `superpixels3`

uses a distance
metric to determine the closest cluster center for each pixel. This distance
metric combines intensity distance and spatial distance.

The function's `Compactness`

argument comes from the mathematical form of
the distance metric. The compactness parameter of the algorithm is a scalar
value that controls the shape of the superpixels. The distance between two
pixels *i* and *j*, where
*m* is the compactness value, is:

$$\begin{array}{l}{d}_{\mathrm{int}ensity}=\sqrt{{\left({l}_{i}-{l}_{j}\right)}^{2}}\\ {d}_{spatial}=\sqrt{{({x}_{i}-{x}_{j})}^{2}+{({y}_{i}-{y}_{j})}^{2}+{({z}_{i}-{z}_{j})}^{2}}\\ D=\sqrt{{(\frac{{d}_{\mathrm{int}ensity}}{m})}^{2}+{(\frac{{d}_{spatial}}{S})}^{2}}\end{array}$$

Compactness has the same meaning as in the 2-D `superpixels`

function: It
determines the relative importance of the intensity distance and the spatial
distance in the overall distance metric. A lower value makes the superpixels
adhere to boundaries better, making them irregularly shaped. A higher value
makes the superpixels more regularly shaped. The dynamic range of input
images is normalized within the algorithm to be from 0 to 1. This enables a
consistent meaning of compactness values across images.

## Extended Capabilities

## Version History

**Introduced in R2016b**

## See Also

`superpixels`

| `boundarymask`

| `imoverlay`

| `label2idx`

| `label2rgb`

| `hyperslic`