Version:

Last Modified: June 25, 2019

Filters a signal with a specific structure element using a mathematical morphological filter.

Method by which to extend the input signal at both ends of the sequence.

Name | Value | Description |
---|---|---|

Zero padding | 0 | Extends the input signal by padding zeros at both ends of the original signal. |

Symmetric | 1 | Extends the input signal to form a new sequence that is symmetric at both ends of the original signal. |

Periodic | 2 | Extends the input signal to form a new sequence that is periodic at both ends of the original signal. |

Filtering a Signal with the Zero Padding Method

Filtering a Signal with the Symmetric Method

Filtering a Signal with the Periodic Method

**Default:
**Zero padding

Structure element to use in the filtering process.

Fundamental operation of the morphological filter.

Name | Value | Description |
---|---|---|

Dilation | 0 | Specifies to perform dilation on the input signal. |

Erosion | 1 | Specifies to perform erosion on the input signal. |

Algorithm and Example for the Dilation Operation

The dilation of a 1D signal
*f*
is defined as follows:

$D\left(i\right)=\mathrm{max}\left\{x(i-j)+s\left(j\right)\right\},\text{}\text{}0\le i\le n-1,\text{}0\le j\le k-1$

where
*x*(*i*) is the
*i*th element in the input signal and
*s*(*j*) is the
*j*th element in
**structure element**.

The following image shows an example of the dilation effect. The original signal consists of two pulses with widths of 20, and the
**structure element**
is an array of ten zeros. The filtered signal expands the pulses in the original signal.

Algorithm and Example for the Erosion Operation

The erosion of a 1D signal
*f*
is defined as follows:

$E\left(i\right)=\mathrm{min}\left\{x(i+j)-s\left(j\right)\right\},\text{}\text{}0\le i\le n-1,\text{}0\le j\le k-1$

where
*x*(*i*) is the
*i*th element in the input signal and
*s*(*j*) is the
*j*th element in
**structure element**.

The following image shows an example of the erosion effect. The original signal consists of two pulses with widths of 20, and the
**structure element**
is an array of ten zeros. The filtered signal shrinks the pulses in the original signal.

**Default:
**Dilation

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an
**error in**
input and an
**error out**
output so that the node can respond to and communicate errors that occur while code is running. The value of
**error in**
specifies whether an error occurred before the node runs. Most nodes respond to values of
**error in**
in a standard, predictable way.

**Default:
**No error

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

**error in**
input and an
**error out**
output so that the node can respond to and communicate errors that occur while code is running. The value of
**error in**
specifies whether an error occurred before the node runs. Most nodes respond to values of
**error in**
in a standard, predictable way.

**Where This Node Can Run:
**

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application