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--- Steerable Pyramid Software Library ---
--- Designed by Eero Simoncelli, Rob Buccigrassi and Hany Farid. ---
--- Original Concept: see references below. ---
--- Source code by Rob Buccigrassi. ---
--- Filter designs by Eero Simoncelli and Anestis Karasaridis. ---
--- Developed at the GRASP Laboratory, Computer and ---
--- Information Science Department, University of Pennsylvania. ---
--- Copyright 1995, University of Pennsylvania ---
--- All rights reserved. ---
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Permission to use, copy, or modify this software and its documentation
for educational and research purposes only and without fee is hereby
granted, provided that this copyright notice and the original authors'
names appear on all copies and supporting documentation. For any
other uses of this software, in original or modified form, including
but not limited to distribution in whole or in part, specific prior
permission must be obtained from University of Pennsylvania and the
authors. These programs shall not be used, rewritten, or adapted as
the basis of a commercial software or hardware product without first
obtaining appropriate licenses from U. Pennsylvania. The University
makes no representations about the suitability of this software for
any purpose. It is provided "as is" without express or implied
warranty.
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The following is an important subset of the functions in this pyramid
library. Please see the header files for a list of all the available
functions.
There are three primary data structures in this library: PFILTER (the
set of filters used to construct and collapse a pyramid), PYRAMID (the
set of subbands that result from applying pyramid filters to an image), and
MATRIX (the representation of a matrix or grayscale image).
Pyramid Filter Functions (spyramid.h):
PFILTER LoadPFilter(char *filename)
Loads the file given in "filename" into a PFILTER structure. If
there is an error, LoadPFilter returns NULL.
MATRIX GetHighbandFilter(PFILTER P);
Given a PFILTER structure, this returns the matrix of the highband
filter (H0 of the diagram in the README file).
Since MATRIX is actually a pointer, any modification made
to the resulting matrix will actually modify the highband filter of
the pyramid filter set.
MATRIX GetFirstLowbandFilter(PFILTER P);
Given a PFILTER structure, this returns the matrix of the first
lowband filter (L0 of the diagram in the README file).
Since MATRIX is actually a pointer, any modification made
to the resulting matrix will actually modify the lowband filter of
the pyramid filter set.
MATRIX GetSecondLowbandFilter(PFILTER P);
Given a PFILTER structure, this returns the matrix of the second
lowband filter (L1 of the diagram in the README file).
Since MATRIX is actually a pointer, any modification made
to the resulting matrix will actually modify the lowband filter of
the pyramid filter set.
MATRIX GetSubbandFilter(PFILTER P, int subband_number);
This returns the subband filter with the given number (the first
subband has number 0). Again, it returns a pointer to the
actual subband filter in the pyramid filter set.
Pyramid functions (spyramid.h):
PYRAMID CreatePyramid(MATRIX image, PFILTER pf, int levels);
This creates a pyramid out of the given image and pyramid filter
set. The number of levels in the pyramid is set by the "levels"
argument.
MATRIX SteerPyramid(PYRAMID pyr, int level, float angle);
This returns a steering of the subbands at the given level (the
first level being level 0) at the given angle.
MATRIX SteerPyramidPointwise(PYRAMID pyr, int level, MATRIX angles);
Given a matrix of angles (which must be the same size as the
subband at the specified level), it returns a steering of the
subbands at the given level (the first level being level 0) so that
point (x,y) of the resulting matrix is at the angle specified at
point (x,y) of the matrix "angles".
MATRIX CollapsePyramid(PYRAMID pyr);
This returns the matrix that is the result of collapsing the
pyramid.
MATRIX GetHighbandImage(PYRAMID pyr);
MATRIX GetLowbandImage(PYRAMID pyr);
This returns the highband and lowband respectively of the pyramid.
Since MATRIX is actually a pointer, it returns the actual matrix
in the pyramid.
MATRIX GetSubbandImage(PYRAMID pyr, int level, int subband_number);
This returns the subband image at the given level (starting at 0)
and the given subband number (starting at 0) of the pyramid.
Since MATRIX is a pointer, it returns the actual matrix in the
pyramid.
Pyramid and Pfilter display functions (spyramid_pgm.h):
void DisplayPfilter(PFILTER PF,int idispwin,char* name,int xloc, int yloc);
This displays the filters of a pyramid filter on window number
"idispwin" (starting at 0). The title of the window is the string
"name" and it appears at location (xloc,yloc).
void DisplayPyramid(PYRAMID pyr, int subband, int idispwin, char* name,
int xloc, int yloc);
This displays a pyramid on window number "idispwin" (starting at 0).
The title of the window displayed is "name", and appears at
location (xloc, yloc).
Matrix functions (matrix,h):
matrix.h has the prototpyes of a rather extensive library of matrix
routines, including loading and saving to files, multiplying, adding
and convolving.
Matrix display functions (matrix_pgm.h):
matrix_pgm.h has the prototypes of routines that can save matrices as
PGM files and display matrices on X windows.