Description of slresizeimg

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slresizeimg

PURPOSE

SLRESIZEIMG Resizes the images by interpolation

SYNOPSIS

function rimgs = slresizeimg(imgs, newsiz, interpker)

DESCRIPTION

SLRESIZEIMG Resizes the images by interpolation

 $ Syntax $
   - rimgs = slresizeimg(imgs, newsiz, interpker)

 $ Arguments $
   - imgs:         The set of images
   - newsiz:       The new image size to be resized to
                   It can be in two forms:
                   - [new_height, new_width]
                   - ratio to the original size
   - interpker:    The interpolation kernel (default = 'linear')
   - rimgs:        The resized images

 $ Description $
   - rimgs = slresizeimg(imgs, newsiz, interpker) resizes the image
     to new size by interpolation. 

 $ Remarks $
   - The implementation is based on slimginterp.

 $ History $
   - Created by Dahua Lin, on Sep 3, 2006

CROSS-REFERENCE INFORMATION

This function calls:

• slimginterp SLIMGINTERP Performs image based interpolation
• raise_lackinput RAISE_LACKINPUT Raises an error indicating lack of input argument
• sltakeval SLTAKEVAL Extracts the values in an array/cell array to output

This function is called by:

SOURCE CODE

0001 function rimgs = slresizeimg(imgs, newsiz, interpker)
0002 %SLRESIZEIMG Resizes the images by interpolation
0003 %
0004 % $ Syntax $
0005 %   - rimgs = slresizeimg(imgs, newsiz, interpker)
0006 %
0007 % $ Arguments $
0008 %   - imgs:         The set of images
0009 %   - newsiz:       The new image size to be resized to
0010 %                   It can be in two forms:
0011 %                   - [new_height, new_width]
0012 %                   - ratio to the original size
0013 %   - interpker:    The interpolation kernel (default = 'linear')
0014 %   - rimgs:        The resized images
0015 %
0016 % $ Description $
0017 %   - rimgs = slresizeimg(imgs, newsiz, interpker) resizes the image
0018 %     to new size by interpolation.
0019 %
0020 % $ Remarks $
0021 %   - The implementation is based on slimginterp.
0022 %
0023 % $ History $
0024 %   - Created by Dahua Lin, on Sep 3, 2006
0025 %
0026 
0027 %% parse and verify input
0028 
0029 if nargin < 2
0030     raise_lackinput('slresizeimg', 2);
0031 end
0032 h0 = size(imgs, 1);
0033 w0 = size(imgs, 2);
0034 
0035 if isnumeric(newsiz)
0036     if length(newsiz) == 1
0037         h = newsiz * h0;
0038         w = newsiz * w0;
0039     elseif length(newsiz) == 2
0040         [h, w] = sltakeval(newsiz);
0041     else
0042         error('sltoolbox:invalidarg', 'The newsiz is invalid');
0043     end
0044 else
0045     error('sltoolbox:invalidarg', 'The newsiz is invalid');
0046 end
0047 
0048 if nargin < 3 || isempty(interpker)
0049     interpker = 'linear';
0050 end
0051 
0052 %% generate coordinate map
0053 
0054 I = linspace(1, h0, h)';
0055 J = linspace(1, w0, w);
0056 I = I(:, ones(1, w));
0057 J = J(ones(h, 1), :);
0058 
0059 %% Do interpolation
0060 
0061 rimgs = slimginterp(imgs, I, J, interpker);
0062 
0063 
0064

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