www.pudn.com > 2D_phasc_unwrapping_algorithms.zip > PhaseResidues.m, change:2008-12-22,size:1938b

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % PhaseResidues.m calculates the phase residues for a given wrapped phase % image. Note that by convention the positions of the phase residues are % marked on the top left corner of the 2 by 2 regions. % % active---res4---right % | | % res1 res3 % | | % below---res2---belowright % Phase residues with integer multiples of 2*pi are not accounted for, but % these rarely occur. % Created by B.S. Spottiswoode on 07/10/2004 % Last modified on 08/10/2004 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function residue_charge=PhaseResidues(IM_phase, IM_mask); [rows, cols]=size(IM_phase); %The code below is simply a vectorised representation of operations on 2 by 2 %blocks in the matrix IM_active=IM_phase; IM_below=zeros(rows,cols); IM_below(1:rows-1,:)=IM_phase(2:rows,:); IM_right=zeros(rows,cols); IM_right(:,1:cols-1)=IM_phase(:,2:cols); IM_belowright=zeros(rows,cols); IM_belowright(1:rows-1,1:cols-1)=IM_phase(2:rows,2:cols); res1=mod(IM_active - IM_below + pi, 2*pi) - pi; %Wrap the phase differences as we loop around the 2 by 2 blocks res2=mod(IM_below - IM_belowright + pi, 2*pi) - pi; res3=mod(IM_belowright - IM_right + pi, 2*pi) - pi; res4=mod(IM_right - IM_active + pi, 2*pi) - pi; temp_residues=res1+res2+res3+res4; %Sum the phase differences. Positive residues appear as 2*pi, negative as -2*pi. residues=(temp_residues>=6); %Assign 1 to positive residue (which should equal 2*pi) residues=residues - (temp_residues<=-6); %Assign -1 to negative residues (which should equal -2*pi) residues(:,cols)=0; residues(rows,:)=0; %Zero pad the border residues residues(:,1)=0; residues(1,:)=0; residue_charge=residues; residue_sum=sum(sum(abs(residues)));