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imgaussfilt

2-D Gaussian filtering of images

Description

B = imgaussfilt(A) filters image A with a 2-D Gaussian smoothing kernel with standard deviation of 0.5, and returns the filtered image in B.

example

B = imgaussfilt(A,sigma) filters image A with a 2-D Gaussian smoothing kernel with standard deviation specified by sigma.

B = imgaussfilt(___,Name,Value) uses name-value pair arguments to control aspects of the filtering.

Examples

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Read image to be filtered.

I = imread('cameraman.tif');

Filter the image with a Gaussian filter with standard deviation of 2.

Iblur = imgaussfilt(I,2);

Display the original and filtered image in a montage.

montage({I,Iblur})
title('Original Image (Left) Vs. Gaussian Filtered Image (Right)')

Input Arguments

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Image to be filtered, specified as a numeric array of any dimension.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32

Standard deviation of the Gaussian distribution, specified as a positive number or a 2-element vector of positive numbers. If you specify a scalar, then imgaussfilt uses a square Gaussian kernel.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: B = imgaussfilt(A,'FilterSize',3);

Size of the Gaussian filter, specified as a scalar or 2-element vector of positive, odd integers. If you specify a scalar, then imgaussfilt uses a square filter. The default filter size is 2*ceil(2*sigma)+1.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Image padding, specified as one of the following.

ValueDescription
numeric scalarPad image with elements of constant value.
'circular'

Pad with circular repetition of elements within the dimension.

'replicate'

Pad by repeating border elements of array.

'symmetric'

Pad image with mirror reflections of itself.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string

Domain in which to perform filtering, specified as one of the following values:

ValueDescription
'auto'Perform convolution in the spatial or frequency domain, based on internal heuristics.
'frequency'Perform convolution in the frequency domain.
'spatial'Perform convolution in the spatial domain.

Data Types: char | string

Output Arguments

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Filtered image, returned as a numeric array of the same class and size as the input image, A.

Tips

  • If image A contains Infs or NaNs, then the behavior of imgaussfilt for frequency domain filtering is undefined. This can happen if you set the 'FilterDomain' parameter to 'frequency' or if you set it to 'auto' and imgaussfilt uses frequency domain filtering. To restrict the propagation of Infs and NaNs in the output in a manner similar to imfilter, consider setting the 'FilterDomain' parameter to 'spatial'.

  • If you set the 'FilterDomain' parameter to 'auto', then imgaussfilt uses an internal heuristic to determine whether spatial or frequency domain filtering is faster. This heuristic is machine dependent and may vary for different configurations. For optimal performance, try both options, 'spatial' and 'frequency', to determine the best filtering domain for your image and kernel size.

  • If you do not specify the 'Padding' parameter, then imgaussfilt uses 'replicate' padding by default, which is different from the default used by imfilter.

Extended Capabilities

Introduced in R2015a