function?[imageptb]?=?freadenvi（fname）
%?freadenvi??????????-?read?envi?image?（V.?Guissard?Apr?29?2004）
%
%??????Reads?an?image?of?ENVI?standard?type
%?????to?a?[col?x?line?x?band]?MATLAB?array
%?image=freadenvi（fname）
%?[imagep]=freadenvi（fname）
%?[imagept]=freadenvi（fname）
%?[imageptb]?=?freadenvi（fname）
%
%?INPUT?:
%
%?fname?string?giving?the?full?pathname?of?the?ENVI?image?to?read.
%
%?OUTPUT?:
%
%?image-----------?c?by?l?by?b?array?containing?the?ENVI?image?values?organised?in
%?????c?:?cols?l?:?lines?and?b?:?bands.
%?p???1?by?3?vector?that?contains?（1）?the?nb?of?cols?（2）?the?number.
%?????of?lines?and?（3）?the?number?of?bands?of?the?opened?image.
%
%?t???string?describing?the?image?data?type?string?in?MATLAB?conventions.
%?b???string?describing?the?image?data?interleave:bsqbil?or?bip
%
%?NOTE?:?????freadenvi?needs?the?corresponding?image?header?file?generated
%?????automatically?by?ENVI.?The?ENVI?header?file?must?have?the?same?name
%?????as?the?ENVI?image?file?+?the?‘.hdf‘?exention.
%?Revised?by?Hu?Shunshi2011.1.3
%?can?read?bsqbil?and?bip?data?interleave.
%%%%%%%%%%%%%

%?Parameters?initialization
elements={‘samples?‘?‘lines???‘?‘bands???‘?‘data?type?‘?‘interleave?‘};
d={‘bit8‘?‘int16‘?‘int32‘?‘float32‘?‘float64‘?‘uint16‘?‘uint32‘?‘int64‘?‘uint64‘};
interleave={‘bsq‘?‘bil‘?‘bip‘};
%?Check?user?input
if?~ischar（fname）
????error（‘fname?should?be?a?char?string‘）;
end


%?Open?ENVI?header?file?to?retreive?s?l?b?&?d?variables
rfid?=?fopen（strcat（fname‘.hdr‘）‘r‘）;

%?Check?if?the?header?file?is?correctely?open
if?rfid?==?-1
????error（‘Input?header?file?does?not?exist‘）;
end;

%?Read?ENVI?image?header?file?and?get?p（1）?:?nb?samples
%?p（2）?:?nb?lines?p（3）?:?nb?bands?t?:?data?type?and?b:interleave
while?1
????tline?=?fgetl（rfid）;
????if?~ischar（tline）?break?end
????[firstsecond]=strtok（tline‘=‘）;
???
????switch?first
????????case?elements（1）
????????????[fs]=strtok（second）;
????????????p（1）=str2num（s）;
????????case?elements（2）
????????????[fs]=strtok（second）;
????????????p（2）=st