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Gaussian Pyramid

Perform Gaussian pyramid decomposition

  • Library:
  • Computer Vision Toolbox / Transforms

  • Gaussian Pyramid block

Description

The Gaussian Pyramid block computes Gaussian pyramid reduction or expansion to resize an image. The image reduction process involves lowpass filtering and then downsampling the image pixels. The image expansion process involves upsampling and then lowpass filtering the image pixels. You can also use this block to build a Laplacian pyramid.

Ports

Input

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Input image, specified as a scalar, a vector, an M-by-N matrix, or an M-by-N-by-C array. C is the number of color channels in the input image. To specify this input as a scalar or vector, you must set the Operation parameter to Expand.

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

Output

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Output image, returned as a scalar, a vector, a matrix, or an array. The dimensions of the output image are determined by the Operationand Pyramid level parameter values. For this port to return a scalar or vector, you must set the Operation parameter to Reduce.

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

Parameters

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Select the Gaussian pyramid operation as one of these methods:

  • Reduce — The block applies a lowpass filter and then downsamples the input image.

  • Expand — The block upsamples and then applies a lowpass filter to the input image.

Specify the factor of 2 by which to upsample or downsample each dimension of the image.

For an M-by-N input image, if you set the Operation parameter to Reduce and the Pyramid level to 1, the dimensions of the output image are ceil(M/2)-by-ceil(N/2).

For an M-by-N input image, if you set the Operation parameter to Expand, the dimensions of the output image are [(M-1)2l+1]-by-[(N-1)2l+1], where the Pyramid level parameter l must be a positive integer.

Specify the lowpass filter coefficient source as Default separable filter [1/4-a/2 1/4 a 1/4 1/4-a/2] or Specify via dialog.

Specify the separable filter coefficients as a vector.

Specify the hidden separable filter coefficients as a vector.

Block Characteristics

Data Types

double | fixed point | integer | single

Multidimensional Signals

yes

Variable-Size Signals

yes

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a

See Also

Blocks