function  [img, header, errmsg] = nano2read(filename)
%NANO2READ  Read the header and the image from a nanoscope 2 file.
%
%       [I, H, ERRMSG] = NANO2READ(FILENAME, OPTION)
%
%       Return:     1) The header of the file, empty on error.
%                   2) The image matrix, empty on error.
%                   3) An error message if occours.
%
%    OPTION can be:  FIRST   -return the first image
%            SECOND  -return the second image
%            BOTH    -return both images in one matrix
%
%    On error, an error message is displayed if nargout < 3.
%       After read the file the image is 90 degree rotated and
%    the bytes are flipped in order to be reproducible
%    with the nanoscope.
%
%       Claudio  11 Oct, 1995.
%

%
% Copyright (c) 1995 by Claudio Rivetti and Mark Young
% claudio@alice.uoregon.edu,    mark@alice.uoregon.edu
%

global Original_NANO2_header


HEADER_SIZE_NS2 = 2048;

fp = fopen(filename, 'r');

if fp == -1
    if nargout==3
      errmsg='File not found';
    else
      error('File not found');
    end
    return;
end

[header,n] = fread(fp, HEADER_SIZE_NS2, 'char');
header=setstr(header)';


if n~=HEADER_SIZE_NS2  |  isempty(findstr(header, 'z_scale'))
    fclose(fp);
    if nargout==3
      errmsg='Wrong file format';
    else
      error('Wrong file format');
    end
    return
end

header=strrep(header, [13 10], [13 10, '\']);
header=['\*' header];
header=strrep(header, [13 10 92 32 ], 32);
header=strrep(header, [92 26], 26);
header=strrep(header, ' =', ':');
Original_NANO2_header=header;

header=setparameter(header, '*ALEX Header', '');
header=setparameter(header, 'File Type', 'NANO2');
header=setparameter(header, 'Date', getparameter(header, 'time',1));
header=setparameter(header, 'Data length', HEADER_SIZE_NS2);
qq=getparameter(header, 'num_samp',1);
header=setparameter(header, 'Samps/line', [qq qq]);
header=setparameter(header, 'Serial number', ' ');
header=setparameter(header, 'Id', getparameter(header, 'h_id',1));
header=setparameter(header, 'X offset', '0 nm');
header=setparameter(header, 'Y offset', '0 nm');
qq=getparameter(header, 'scan_sz',1);
header=setparameter(header, 'Scan size', [num2str(qq) ' nm']);
f=getparameter(header, 'z_scale', 1)/16385;
header=setparameter(header, 'Trasform. Factor', f);
header=setparameter(header, 'Note', [getparameter(header, 'text',1) ' ']);

header=strrep(header, '  ', ' ');
header=strrep(header, '  ', '');

hlen=length(header);
if hlen > HEADER_SIZE_NS2
  header=header(1:HEADER_SIZE_NS2);
else
  header=[header zeros(1,HEADER_SIZE_NS2-hlen)]; 
end

msize=getparameter(header, 'Samps/line',2);
img = fread(fp, msize, 'short', 'vaxd');
fclose(fp);

img = rot90(img);
return