# Dilation

Dilate binary or intensity images by finding local maxima

• Library:
• Computer Vision Toolbox / Morphological Operations

## Description

The Dilation block performs morphological dilation on an intensity or binary image and outputs the dilated image.

To define the structuring element that the block applies to the image, use the Neighborhood or structuring element parameter. Specify this element by entering a vector or matrix of `1`s and `0`s or by using the `strel` function.

The Dilation block rotates the structuring element about its origin (if it is unsymmetrical), and places this origin over each pixel of the image object. The block creates the output matrix, that is, the dilated image, from the local maxima values found at each pixel.

This block uses two-dimensional flat structuring elements only.

## Ports

### Input

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Specify an input image as a matrix of intensity values. This port is unnamed unless you set the Neighborhood or structuring element source parameter to `Input port`.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `uint8` | `uint16` | `uint32` | `Boolean` | `fixed point`

Specify neighborhood values representing a structuring element as a vector or matrix of `1`s and `0`s or by using the `strel` function.

#### Dependencies

To enable this port, set the Neighborhood or structuring element source parameter to `Input port`.

Data Types: `Boolean`

### Output

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The dilated image is returned as a matrix of intensity values. The size and datatype of the output image are the same as those of the input image.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `uint8` | `uint16` | `uint32` | `Boolean` | `fixed point`

## Parameters

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Specify the source of neighborhood or structuring element as one of these options:

• `Specify via dialog` — Use the Neighborhood or structuring element parameter to specify a neighborhood or structuring element.

• `Input port` — Use the Nhood input port to specify neighborhood values representing a structuring element.

Specify neighborhood or structuring element as a vector or matrix of `1`s and `0`s, a `strel` object or an array of `strel` objects. When you specify an array of `strel` objects, the block applies each object to the entire image in turn.

If the structuring element is decomposable into smaller elements, the block executes at higher speed due to the use of a more efficient algorithm.

#### Dependencies

To enable this parameter, set the Neighborhood or structuring element source parameter, to ```Specify via dialog```.

## Block Characteristics

 Data Types `Boolean` | `double` | `fixed point` | `integer` | `single` Multidimensional Signals `no` Variable-Size Signals `yes`

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## References

[1] Soille, Pierre. Morphological Image Analysis. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. https://doi.org/10.1007/978-3-662-05088-0.

[2] Gonzalez, Rafael C., Richard E. Woods, and Steven L. Eddins. Digital Image Processing Using MATLAB. Third edition. Knoxville: Gatesmark Publishing, 2020.

## Extended Capabilities

### Objects

Introduced before R2006a