Hassan wrote:
> On Nov 23, 12:18 am, Jiek <676215...@qq.com> wrote:
>> On Nov 23, 5:35 am, Hassan <hkhav...@gmail.com> wrote:
>>
>>> I used the following code to display the image:
>>> image=read_tiff(file)
>>> imagesize=[62,488,290]
>>> DEVICE, DECOMPOSED = 0
>>> LOADCT, 38
>>> WINDOW, 0, XSIZE = imageSize[1], YSIZE = imageSize[2]
>>> TV, Image(0,*,*), 0
>>> but there are two problems: first it's displayed upside-down and
>>> second the way it shows the image is quite different with other
>>> softwares like ENVI, it's more like the image is shown in 256-color
>>> table or something like that.
>> I found a function to read ENVI image and it work well.As follows:
>> pro read_envi_image, infile, img, xs, ys, type, offset, mapinfo
>>
>> ;
>> ; Copyright (c) 2003,Institute of Photogrammetry and Remote Sensing, ;
>> (IPF),
>> ; Technical University of Vienna. Unauthorised reproduction
>> prohibited.
>> ;
>> ;+
>> ; NAME:
>> ; read_envi_file
>> ;
>> ; PURPOSE:
>> ; IDL program, which reads standard ENVI image files (*.img).
>> ;
>> ;
>> ; CATEGORY:
>> ; Input_Output
>> ;
>> ; CALLING SEQUENCE:
>> ; read_envi_file, infile, img, xs, ys, type,offset
>> ;
>> ; INPUTS:
>> ; infile - input file name
>> ;
>> ; OPTIONAL INPUTS:
>> ; None
>> ;
>> ; KEYWORD PARAMETERS:
>> ; None
>> ;
>> ; OUTPUTS:
>> ; img - ENVI image file, 2D array
>> ; xs - number of samples
>> ; ys - number of lines
>> ; type - image data type
>> ; offset - headeroffset
>> ; mapinfo - information on spatial resolution (spacing) and
>> coordinates
>> ; of upper left corner (ulx, uly)
>> ;
>> ;
>> ; OPTIONAL OUTPUTS:
>> ; None
>> ;
>> ; COMMON BLOCKS:
>> ; none
>> ;
>> ; SIDE EFFECTS:
>> ;
>> ; RESTRICTIONS:
>> ; None
>> ;
>> ; PROCEDURE:
>> ;
>> ; EXAMPLE:
>> ;
>> ; REMARKS
>> ; None
>> ;
>> ; MODIFICATION HISTORY:
>> ; Written by: Carsten Pathe, c...@ipf.tuwien.ac.at
>> ; Date: 25.08.2003
>> ;
>> ;-
>>
>> image = infile
>>
>> header = strsplit(infile,'.',/extract)
>> header = header(n_elements(header)-2)+'.hdr'
>>
>> openr, unit, header, /get_lun
>>
>> header_line = ''
>>
>> while not eof(unit) do begin
>>
>> readf, unit, header_line
>> tmp = strsplit(header_line(0), '=', /extract)
>> header_keyword = strsplit(tmp(0), ' ', /extract)
>>
>> print, header_keyword
>>
>> if header_keyword(0) eq 'samples' then xs = long(tmp(1))
>> if header_keyword(0) eq 'lines' then ys = long(tmp(1))
>> if header_keyword(0) eq 'header' then offset = long(tmp(1))
>> if header_keyword(0) eq 'data' then type = long(tmp(1))
>>
>> if header_keyword(0) eq 'map' then begin
>>
>> mapinfo_tmp=strsplit(tmp(1),'{',/extract)
>> mapinfo_tmp=strsplit(mapinfo_tmp(1),',',/extract)
>>
>> mapinfo={ulx:0.,uly:0.,spacing:0.}
>> mapinfo.ulx=mapinfo_tmp(3)
>> mapinfo.uly=mapinfo_tmp(4)
>> mapinfo.spacing=mapinfo_tmp(5)
>>
>> endif
>>
>> endwhile
>>
>> close,unit & free_lun, unit
>> print, xs, ys
>>
>> if type eq 1 then img=bytarr(xs, ys)
>> if type eq 2 then img=intarr(xs, ys)
>> if type eq 4 then img=fltarr(xs, ys)
>> if type eq 12 then img=uintarr(xs, ys)
>>
>> openr, unit,image, /get_lun
>> point_lun, unit, offset
>> readu, unit, img
>> close, unit & free_lun, unit
>>
>> end
>
> I run it but it seems it imports just one band, right? is the output
> variable named 'img'?
This function is incomplete. You can customize it so it also reads the
number of bands... and the band data.
Also, if you read an Envi file, you may be interested in reading the
lookup table from the header (if any), so that you can display the data
with the exact same color in Envi and in IDL.
By the way, you say you want to do this in IDL, but you didn't specify
if you have to get rid of using Envi or not. If not, you can use the
following (note: again, the info read in the header is incomplete and
suits my need... feel free to read more info, such as the number of
bands AND the information on the band interleave..
;Open the file in envi
ENVI_OPEN_FILE, fileToOpen, /NO_REALIZE , R_FID=FID
;If it is a valid file, read the header
if (fid[0] eq -1) then return, -1
envi_file_query, fid, ns=dimX, nl=dimY, nb=nbBands, DATA_TYPE=dataType,$
OFFSET = HeaderOffSet, LOOKUP= lookup, class_names = classNames,$
num_classes = numClasses
map_Info = ENVI_GET_MAP_INFO(FID=FID)
;Pack the header info in a structure (optional)
headerInfo = {ns:dimX, nl:dimY, lookup:lookup, map_info:map_Info,$
class_names:classNames, num_classes:numClasses}
;Read the data in IDL
data = read_binary(fileToOpen,data_Start = HeaderOffSet,$
data_Type=dataType, data_Dims=[dimX,dimY],ENDIAN = "native")
Jean
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