Home > SaliencyToolbox > makeRedGreenPyramid.m

makeRedGreenPyramid

PURPOSE ^

makeRedGreenPyramid - creates a red-green opponency pyramid

SYNOPSIS ^

function [rgPyr,rPyr,gPyr] = makeRedGreenPyramid(image,type)

DESCRIPTION ^

 makeRedGreenPyramid - creates a red-green opponency pyramid

 [rgPyr,rPyr,gPyr] = makeRedGreenPyramid(image,type)
    Creates a gaussian pyramid from a red-green opponency map (rgPyr)
    of image and, if requested, also the separate red (rPyr)
    and green (gPyr) pyramids.
      Image - Image structure for the input image.
      type - 'dyadic' or 'sqrt2'

 For a dicussion of the particular definitions of color opponency used here, 
 see appendix A.2 of Dirk's PhD thesis:
    Walther, D. (2006). Interactions of visual attention and object recognition: 
    Computational modeling, algorithms, and psychophysics. Ph.D. thesis.
    California Institute of Technology. 
    http://resolver.caltech.edu/CaltechETD:etd-03072006-135433.

 See also makeBlueYellowPyramid, getRGB, makeGaussianPyramid, makeFeaturePyramids, dataStructures.

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 % makeRedGreenPyramid - creates a red-green opponency pyramid
0002 %
0003 % [rgPyr,rPyr,gPyr] = makeRedGreenPyramid(image,type)
0004 %    Creates a gaussian pyramid from a red-green opponency map (rgPyr)
0005 %    of image and, if requested, also the separate red (rPyr)
0006 %    and green (gPyr) pyramids.
0007 %      Image - Image structure for the input image.
0008 %      type - 'dyadic' or 'sqrt2'
0009 %
0010 % For a dicussion of the particular definitions of color opponency used here,
0011 % see appendix A.2 of Dirk's PhD thesis:
0012 %    Walther, D. (2006). Interactions of visual attention and object recognition:
0013 %    Computational modeling, algorithms, and psychophysics. Ph.D. thesis.
0014 %    California Institute of Technology.
0015 %    http://resolver.caltech.edu/CaltechETD:etd-03072006-135433.
0016 %
0017 % See also makeBlueYellowPyramid, getRGB, makeGaussianPyramid, makeFeaturePyramids, dataStructures.
0018 
0019 % This file is part of the SaliencyToolbox - Copyright (C) 2006-2013
0020 % by Dirk B. Walther and the California Institute of Technology.
0021 % See the enclosed LICENSE.TXT document for the license agreement.
0022 % More information about this project is available at:
0023 % http://www.saliencytoolbox.net
0024 
0025 function [rgPyr,rPyr,gPyr] = makeRedGreenPyramid(image,type)
0026 
0027 declareGlobal;
0028 
0029 im = loadImage(image);
0030 [r,g,b,in] = getRGB(im);
0031 
0032 rg = safeDivide((r-g),in);
0033 
0034 if (nargout >= 1)
0035   map.origImage = image;
0036   map.label = 'Red/Green';
0037   map.data = rg;
0038   map.date = clock;
0039   rgPyr = makeGaussianPyramid(map,type);
0040 end
0041 
0042 if (nargout >= 2)
0043   map.origImage = image;
0044   map.label = 'Red';
0045   rr = clamp(rg,0);
0046   map.data = rr;
0047   map.date = clock;
0048   rPyr = makeGaussianPyramid(map,type);
0049 end
0050 
0051 if (nargout >= 3)
0052   map.origImage = image;
0053   map.label = 'Green';
0054   gg = clamp(-rg,0);
0055   map.data = gg;
0056   map.date = clock;
0057   gPyr = makeGaussianPyramid(map,type);
0058 end

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