Description of slcalcpadsize

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slcalcpadsize

PURPOSE

SLCALCPADSIZE Calculates the size of padding

SYNOPSIS

function [paddedsiz, roi, bmg] = slcalcpadsize(varargin)

DESCRIPTION

SLCALCPADSIZE Calculates the size of padding

 $ Syntax $
   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, bmg0)
   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, roi0, bmg0)

 $ Arguments $
   - imgsize:      The whole size of the image
   - roi0:         The rectangle of the target region 
                   in the form of [t, b, l, m]
   - bmg0:         The required boundary margins for the target region
                   in the form [tm, bm, lm, rm]
   - paddedsize:   The size of the padded image
   - roi:          The rectangle of the target region in the padded image
   - bmg:          The boundary margins for padding on the whole image

 $ Description $
   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, bmg0) calculates
     the padding size when the target region is the whole image.

   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, roi0, bmg0) calculates
     the padding size with the target region explicitly specified.

 $ History $
   - Created by Dahua Lin, on Sep 1st, 2006

CROSS-REFERENCE INFORMATION

This function calls:

• 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:

• slpixneighbors SLPIXNEIGHBORS Extracts the neighborhood of pixels from an image

SOURCE CODE

0001 function [paddedsiz, roi, bmg] = slcalcpadsize(varargin)
0002 %SLCALCPADSIZE Calculates the size of padding
0003 %
0004 % $ Syntax $
0005 %   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, bmg0)
0006 %   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, roi0, bmg0)
0007 %
0008 % $ Arguments $
0009 %   - imgsize:      The whole size of the image
0010 %   - roi0:         The rectangle of the target region
0011 %                   in the form of [t, b, l, m]
0012 %   - bmg0:         The required boundary margins for the target region
0013 %                   in the form [tm, bm, lm, rm]
0014 %   - paddedsize:   The size of the padded image
0015 %   - roi:          The rectangle of the target region in the padded image
0016 %   - bmg:          The boundary margins for padding on the whole image
0017 %
0018 % $ Description $
0019 %   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, bmg0) calculates
0020 %     the padding size when the target region is the whole image.
0021 %
0022 %   - [paddedsiz, roi, bmg] = slcalcpadsize(imgsize, roi0, bmg0) calculates
0023 %     the padding size with the target region explicitly specified.
0024 %
0025 % $ History $
0026 %   - Created by Dahua Lin, on Sep 1st, 2006
0027 %
0028 
0029 %% parse and verify input arguments
0030 
0031 if nargin < 2
0032     raise_lackinput('slcalcpadsize', 2);
0033 end
0034 
0035 imgsize = varargin{1};
0036 h0 = imgsize(1); w0 = imgsize(2);
0037 if nargin == 2 
0038     roi0 = [1, h0, 1, w0];
0039     bmg0 = varargin{2};
0040 else 
0041     if isempty(varargin{2})
0042         roi0 = [1, h0, 1, w0];
0043     else
0044         roi0 = varargin{2};
0045     end
0046     bmg0 = varargin{3};
0047 end
0048 
0049 %% compute padding boundary
0050 
0051 [t0, b0, l0, r0] = sltakeval(roi0);
0052 inner_mgs = [t0 - 1, h0 - b0, l0 - 1, w0 - r0];
0053 
0054 bmg = max(bmg0 - inner_mgs, 0);
0055 
0056 %% compute padded size
0057 
0058 ph = h0 + bmg(1) + bmg(2);
0059 pw = w0 + bmg(3) + bmg(4);
0060 paddedsiz = [ph, pw];
0061 
0062 %% compute roi in padded image
0063 
0064 roi = [bmg(1) + t0, bmg(1) + b0, bmg(3) + l0, bmg(3) + r0];
0065

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