REDUCE2D_BASE - Base function for REDUCE2D.

Contents

Syntax

  Ir = REDUCE2D_BASE(I, filter, order);

See also

Ressembles: REDUCE2D, PYRDOWN, EXPAND2D_BASE. Requires: REDUCE2D_MEX.

Function implementation

function Ir = reduce2d_base(I, filter, order)

dealing with multispectral images

[X,Y,C] = size(I);
if X<2 || Y<2,  return;  end;   % otherwise we can crash matlab!!!

if C>1
    Ir = zeros(floor(X/2),floor(Y/2),C);
    for c=1:C
            Ir(:,:,c) = reduce2d_base(I(:,:,c), filter, order);
    end
    return;
end

main program

if strcmpi(filter,'lpl')

classical Laplacian pyramid: Matlab implementation

    h = [1 4 6 4 1]/16;
    Ir = conv2(h, h, I, 'same');
    Ir = Ir(1:2:X,1:2:Y);

else

calling the mex program for spline based pyramids

    Ir = reduce2d_mex(I, filter, order);

end

end % end of reduce2d_base