Gaussian Pyramid - Expand and Reduce routines 1D, 2D and 3D

This contains set of routines, for the 'expand' and 'reduce' operations of Gaussian Image Pyramids f

Description

This contains the code for the 'Expand' and 'Reduce' routines for Gaussian image pyramids, as discussed in the Paper - "
The Laplacian Pyramid as a Compact Image Code" - Burt and Adelson, 1983.

Important applications of the same include motion estimation.

These two functions were originally submitted by Karthik Kumar Arun Kumar, E-mail: [e-mail].
Karthik's functions were working only for 2D images, and they were relatively slow.

I have improved both functions to make them working for 1D, 2D and 3D images. Output images will have
the same data type of the original image, and both functions are working much faster now.

Acknowledgements

The author wishes to acknowledge the following in the creation of this submission:
Gaussian Pyramid - Expand and Reduce routines

• MATLAB release: MATLAB 6.5.1 (R13SP1)

[DO Quoc Bao]

Thanks for sharing

[Joe C]

Good stuff.

But I can't understand why you pad two rows/columns in 'REDUCE' but only pad one row/column for 'EXPAND'

[Andrea Tagliasacchi]

I am not sure about Joe's comment, I don't need it to THAT amount of details. MATLAB provides its own laplacian in the image toolbox: "impyramid(image,'reduce')".

However, the one provided in the image toolbox is not an invertible operation (you cannot obtain the original image by an update and then a reduce, as the sizes of these output matrices don't match... making that implementation useless....

[Angel Cruz]