mmtable.rar_图像插补

function y=mmtable(a,b,c) %MMTABLE 1-D Monotonic Table Search by Linear Interpolation. % YI=MMTABLE(TAB,COL,VALS) linearly interpolates the table TAB % searching for values VALS in the column COL. % % TAB(:,COL) must be monotonic, but need NOT be equally spaced. % YI has as many rows as VALS and as many columns as TAB. % NaNs are returned where VALS are outside the range of TAB(:,COL). % % YI=MMTABLE(TAB,VALS) interpolates using COL=1 and does not return % TAB(:,1) in Y. This matches the usage of TABLE1(TAB,X0). % % YI=MMTABLE(X,Y,XI) interpolates the vector X to find YI associated % with XI. This matches the usage of INTERP1(X,Y,XI) % % This routine is 10X faster than TABLE1 which is called by INTERP1. % For linearly spaced data, ILINEAR is 10X faster yet. % D.C. Hanselman, University of Maine, Orono ME, 04469 % 8/21/95 % Copyright (c) 1996 by Prentice-Hall, Inc. if nargin==2 % MMTABLE(TAB,VALS) syntax tab=a;vals=b(:);col=1;cflag=1; elseif length(b)>1 % MMTABLE(X,Y,XI) syntax [rb,cb]=size(b); a=a(:); la=length(a); if rb==la,tab=[a b]; elseif cb==la,tab=[a b.']; end col=1;vals=c(:);cflag=1; else % MMTABLE(TAB,COL,VALS) syntax tab=a;col=b(1);vals=c(:);cflag=0; end [rt,ct]=size(tab); if col>ct|col<1, error('Chosen column outside table width.'), end if rt<2, error('Table too small or not oriented in columns.'), end ict=1:ct; % index for table columns nv=length(vals); dx=diff(tab); dx=[dx;dx(rt-1,:)]; % differences within each column. id=sign(dx(1,col)); % sign of differences in col if any(sign(dx(:,col))~=id) error(sprintf('Column %.0f of table is not monotonic.',col)) end inan=vals<min(tab(1,col),tab(rt,col)) | vals>max(tab(1,col),tab(rt,col)); xo=vals(~inan); % pick values within range of tab(:,col) nxo=length(xo); if nxo==0 % all values are outside range of tab(:,col)! y=NaN*ones(nv,ct); y(:,col)=vals; else % interpolate using algorithm posted by Hans Olsson of Lund University [svals,sidx]=sort(id*[tab(2:rt-1,col);xo]); ttab=sidx<=rt-2; % True at tab(:,col) values in svals cidx=1+cumsum(ttab); % index of xo in svals sidx(ttab)=[]; % throw out indices of tab(:,col) values yidx=zeros(nxo,1); % storage for xo index in tab(:,col) yidx(sidx-(rt-2))=cidx(~ttab); % xo index in tab(:,col) ndx=(xo-tab(yidx,col))./dx(yidx,col); % normalized dx increment y=tab(yidx,ict)+ndx(:,ones(1,ct)).*dx(yidx,ict); if ~isempty(inan) % must poke in NaNs where they belong yt=zeros(nv,ct); yt(~inan,:)=y; yt(inan,:)=NaN*ones(nv-nxo,ct); yt(:,col)=vals; y=yt; end end if cflag,y(:,col)=[];end