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- % IM = mkDisc(SIZE, RADIUS, ORIGIN, TWIDTH, VALS)
- %
- % Make a "disk" image. SIZE specifies the matrix size, as for
- % zeros(). RADIUS (default = min(size)/4) specifies the radius of
- % the disk. ORIGIN (default = (size+1)/2) specifies the
- % location of the disk center. TWIDTH (in pixels, default = 2)
- % specifies the width over which a soft threshold transition is made.
- % VALS (default = [0,1]) should be a 2-vector containing the
- % intensity value inside and outside the disk.
- % Eero Simoncelli, 6/96.
- function [res] = mkDisc(sz, rad, origin, twidth, vals)
- if (nargin < 1)
- error('Must pass at least a size argument');
- end
-
- sz = sz(:);
- if (size(sz,1) == 1)
- sz = [sz sz];
- end
-
- %------------------------------------------------------------
- % OPTIONAL ARGS:
- if (exist('rad') ~= 1)
- rad = min(sz(1),sz(2))/4;
- end
- if (exist('origin') ~= 1)
- origin = (sz+1)./2;
- end
- if (exist('twidth') ~= 1)
- twidth = 2;
- end
- if (exist('vals') ~= 1)
- vals = [1,0];
- end
- %------------------------------------------------------------
- res = mkR(sz,1,origin);
- if (abs(twidth) < realmin)
- res = vals(2) + (vals(1) - vals(2)) * (res <= rad);
- else
- [Xtbl,Ytbl] = rcosFn(twidth, rad, [vals(1), vals(2)]);
- res = pointOp(res, Ytbl, Xtbl(1), Xtbl(2)-Xtbl(1), 0);
- %
- % OLD interp1 VERSION:
- % res = res(:);
- % Xtbl(1) = min(res);
- % Xtbl(size(Xtbl,2)) = max(res);
- % res = reshape(interp1(Xtbl,Ytbl,res), sz(1), sz(2));
- %
- end
-
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