www.pudn.com > SPIHT_bandelet.rar > perform_alpert_transform_2d.m

function [w,info] = perform_alpert_transform_2d(v,pos,k, dir, options) 
 
% perform_alpert_transform_1p5d - transform a 2D signal. 
% 
% 
%   [w,info] = perform_alpert_transform_1p5d(v,pos,k, dir, options); 
% 
%   'v' is a 1D vector, the value of the function at each sampling location. 
%   'pos' is a 2D vector, pos(:,i) is the ith point. 
%   'k' is the number of vanishing moments (1=>Haar, 2=>linear basis ...). 
%       * 'k' can be an integer, and then the algorithm will use the same 
%         order for X and Y direction. 
%       * 'k' can be a couple of integer k=[kx,ky] and 'kx' will be the 
%         order on the X direction, and 'ky' the order on the Y direction. 
%       * 'k' can be a set of monomial, see below ('degree_type') for 
%         further comments. 
%   'dir' is 1 for fwd transform and -1 for bwd. 
% 
%   'options' is a structure that can contains the followind field : 
%   'degree_type' : Polynomial degree. By default, the multiresolution spaces are defined 
%       as piecewise polynimals P that satisfy 
%           degX(P)m 
                m = m+1; 
                i = 0; 
            end 
        end 
    case 'user_defined' 
        monomials = k; 
    otherwise 
        error('Unknown degree type.'); 
end 
 
k2 = size(monomials,2)/2;     % equivalent to k^2 in Alpert paper. 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% find a regroupement 
if isempty(part) 
    clear options; 
    options.ptmax = k2; 
    options.part_type = part_type; 
    [part,B,G] = dichotomic_grouping(pos,options); 
end 
 
 
if exist('perform_moment_transform')>0 && use_mex 
    w = perform_moment_transform(v,pos, monomials, dir, part); 
    info = []; 
else 
    [w,info] = perform_moment_transform_slow(v,pos, monomials, dir, part); 
end