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R8218/CT/private/parseimagesubheader.m
05ae44827169aterrier-plotUpdate

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parseimagesubheader.m
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function isnitf_meta = parseimagesubheader( fid, dataLength )
%PARSEIMAGESUBHEADER Parse the Image subheaders in an NITF file.
% ISNITF_META = PARSEIMAGESUBHEADER
% Parse the Image Segment Subheader for an NITF 2.1 file.
% Copyright 2007-2009 The MathWorks, Inc.
% TODO: refactor common functions between 2.0 and 2.1 into an external file
% Initialize the image subheader structure
isnitf_meta = struct([]);
fields = {'IM', 'FilePartType', 2
'IID1', 'ImageID1', 10
'IDATIM', 'ImageDateAndTime', 14
'TGTID', 'TargetID', 17
'IID2', 'ImageIID2', 80
'ISCLAS', 'ImageSecurityClassification', 1
'ISCLSY', 'ImageSecurityClassificationSystem', 2
'ISCODE', 'ImageCodewords', 11
'ISCTLH', 'ImageControlAndHandling', 2
'ISREL', 'ImageReleasingInstructions', 20
'ISDCTP', 'ImageDeclassificationType', 2
'ISDCDT', 'ImageDeclassificationDate', 8
'ISDCXM', 'ImageDeclassificationExemption', 4
'ISDG', 'ImageDowngrade', 1
'ISDGT', 'ImageDowngradeDate', 8
'ISCLTX', 'ImageClassificationText', 43
'ISCATP', 'ImageClassificationAuthorityType', 1
'ISCAUT', 'ImageClassificationAuthority', 40
'ISCRSN', 'ImageClassificationReason', 1
'ISSRDT', 'ImageSecuritySourceDate', 8
'ISCTLN', 'ImageSecurityControlNumber', 15
'ENCRYP', 'Encryption', 1
'ISORCE', 'ImageSource', 42
'NROWS', 'NumberOfSignificantRowsInImage', 8
'NCOLS', 'NumberOfSignificantColumnsInImage', 8
'PVTYPE', 'PixelValueType', 3
'IREP', 'ImageRepresentation', 8
'ICAT', 'ImageCategory', 8
'ABPP', 'ActualBitsPerPixelPerBand', 2
'PJUST', 'PixelJustification', 1
'ICORDS', 'ImageCoordinateSystem', 1};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
%ICORDS is the last item extracted in the loop above. Depending
%on its value there will be an IGEOLO or Image Geographic Location field.
%If ICORDS is not a space, add the IGEOLO field to the meta data struct
%and insert values.
icords = deblank(isnitf_meta(end).value);
isnitf_meta = checkIcords(icords, fid, isnitf_meta);
%NICOM
%Depending on its value there will be ICOM fields (ICOM1 through ICOMn).
%If NICOM is not zero, add the comment fields to the meta data struct
%and insert their values.
fields = {'NICOM', 'NumberOfImageComments', 1};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
nicom = sscanf(isnitf_meta(end).value, '%f');
isnitf_meta = checkNicom(nicom, fid, isnitf_meta);
%Next field is Image Compression
fields = {'IC', 'ImageCompression', 2};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
%Next field is COMRAT or Compression Rate Code
%If the IC field is not NC or NM the field will have a value.
ic = isnitf_meta(end).value;
if ~strcmp(ic, 'NC') && ~strcmp(ic, 'NM')
fields = {'COMRAT', 'CompressionRateCode', 4};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
end
fields = {'NBANDS', 'NumberOfBands', 1};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
nbands = sscanf(isnitf_meta(end).value, '%f');
%XBANDS
%If the NBANDS field is 0 XBANDS is the number of bands in a multi-spectral image.
if nbands == 0
fields = {'XBANDS', 'NumberOfMultiSpectralBands', 5};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
bands = sscanf(isnitf_meta(end).value, '%f');
else
bands = nbands;
end
%Set up Band substructure
isnitf_meta(end + 1).name = 'Band Meta';
isnitf_meta(end).vname = 'BandMeta';
%The value will be a structure of band data
%The next seven fields occur for each band as indicated by BANDS
% Lengths:
% IREPBAND 2, ISUBCAT 6, IFC 1, IMFLT 3, NLUTS 1, NELUT 5 [omitted if NLUTS = 0]
% LUTD contains data for the mth LUT of the nnth band
nitf_metaBand(bands).value = '';
for currentBand = 1: bands
isBandnitf_meta = struct([]);
nitf_metaBand(currentBand).name = sprintf('Band%03d', currentBand);
nitf_metaBand(currentBand).vname = [nitf_metaBand(currentBand).name 'Meta'];
nitf_metaBand(currentBand).value = '';
fields = {'IREPBAND%02d', 'BandRepresentation%02d', 2
'ISUBCAT%02d', 'BandSubcategory%02d', 6
'IFC%02d', 'BandImageFilterCondition%02d', 1
'IMFLT%02d', 'BandImageFilterCode%02d', 3
'NLUTS%02d', 'BandNumberOfLUTS%02d', 1};
isBandnitf_meta = nitfReadMetaMulti(isBandnitf_meta, fields, fid, currentBand);
numluts = sscanf(isBandnitf_meta(end).value, '%f');
if numluts ~= 0
%nnth Band Number of LUT Entries
fields = {'NELUT%02d', 'BandNumberOfLUTEntries%02d', 5};
isBandnitf_meta = nitfReadMetaMulti(isBandnitf_meta, fields, fid, currentBand);
numlutentries = sscanf(isBandnitf_meta(end).value', '%f');
%The value will be a struct of LUT data
for currentLut = 1 : numluts
isBandnitf_meta(end + 1).name = sprintf('LUTData%1d', currentLut);
isBandnitf_meta(end).vname = sprintf('LUTData%1d', currentLut);
% Note: not converted to char.
isBandnitf_meta(end).value = fread(fid, numlutentries, 'uint8');
end
end
nitf_metaBand(currentBand).value = isBandnitf_meta;
end
isnitf_meta(end).value = nitf_metaBand;
fields = {'ISYNC', 'ImageSyncCode', 1
'IMODE', 'ImageMode' 1
'NBPR', 'NumberOfBlocksPerRow', 4};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
NBPR = sscanf(isnitf_meta(end).value, '%f');
fields = {'NBPC', 'NumberOfBlocksPerColumn', 4};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
NBPC = sscanf(isnitf_meta(end).value, '%f');
fields = {'NPPBH', 'NumberOfPixelsPerBlockHorizontal', 4
'NPPBV', 'NumberOfPixelsPerBlockVertical', 4
'NBPP', 'NumberOfBitsPerPixelPerBand', 2
'IDLVL', 'DisplayLevel', 3
'IALVL', 'ImageAttachmentLevel', 3
'ILOC', 'ImageLocation', 10
'IMAG', 'ImageMagnification', 4};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
% The IMAG value should be converted to a number from the decimal string.
isnitf_meta(end).value = sscanf(isnitf_meta(end).value, '%f');
fields = {'UDIDL', 'UserDefinedImageDataLength', 5};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
%If UDIDL is not zeros we'll have values for UDOFL and UDID
UDIDL = sscanf(isnitf_meta(end).value, '%f');
if UDIDL ~= 0
fields = {'UDOFL', 'UserDefinedOverflow', 3
'UDID', 'UserDefinedImageData', UDIDL - 3};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
end
fields = {'IXSHDL', 'ExtendedSubheaderDataLength', 5};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
%If IXSHDL is not zeros we'll have values for IXSOFL and IXSHD
IXSHDL = sscanf(isnitf_meta(end).value, '%f');
if IXSHDL ~= 0
fields = {'IXOFL', 'ExtendedSubheaderOverflow', 3
'IXSHD', 'ExtendedSubheaderData', IXSHDL - 3};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
end
% If the image contains data masking, read those values. (See
% MIL-STD-2500B Table A-3(A).
dataMaskTableLength = 0;
if (hasDataMaskTable(ic))
fields = {'IMDATOFF', 'BlockedImageDataOffset', 1, 'int32'
'BMRLNTH', 'BlockedMaskRecordLength', 1, 'uint16'};
isnitf_meta = nitfReadMetaNumeric(isnitf_meta, fields, fid);
BMRLNTH = isnitf_meta(end).value;
fields = {'TMRLNTH', 'PadPixelMaskRecordLength', 1, 'uint16'};
isnitf_meta = nitfReadMetaNumeric(isnitf_meta, fields, fid);
TMRLNTH = isnitf_meta(end).value;
fields = {'TPXCDLNTH', 'TransparentOutputPixelCodeLength', 1, 'uint16'};
isnitf_meta = nitfReadMetaNumeric(isnitf_meta, fields, fid);
TPXCDLNTH = isnitf_meta(end).value;
dataMaskTableLength = dataMaskTableLength + 4 + 2 + 2 + 2;
if (TPXCDLNTH ~= 0)
if (TPXCDLNTH <= 8)
fmt = 'uint8';
dataMaskTableLength = dataMaskTableLength + 1;
else
fmt = 'uint16';
dataMaskTableLength = dataMaskTableLength + 2;
end
fields = {'TPXCD', 'PadOutputPixelCode', 1, fmt};
isnitf_meta = nitfReadMetaNumeric(isnitf_meta, fields, fid);
end
numBlocks = NBPR * NBPC * max(bands, nbands);
if (BMRLNTH ~= 0)
fields = {'BMRnBNDm', 'BlockNBandMOffset', numBlocks, 'uint32'};
isnitf_meta = nitfReadMetaNumeric(isnitf_meta, fields, fid);
dataMaskTableLength = dataMaskTableLength + 4 * numBlocks;
end
if (TMRLNTH ~= 0)
fields = {'TMRnBNDm', 'PadPixelNBandMOffset', numBlocks, 'uint32'};
isnitf_meta = nitfReadMetaNumeric(isnitf_meta, fields, fid);
dataMaskTableLength = dataMaskTableLength + 4 * numBlocks;
end
end
%Move the cursor through the image data
readforwardbytes = sscanf(dataLength, '%f') - dataMaskTableLength;
fseek(fid, readforwardbytes, 'cof');
function isnitf_meta = checkIcords(icords, fid, isnitf_meta)
if ~strcmp(icords, '')
fields = {'IGEOLO', 'ImageGeographicLocation', 60};
isnitf_meta = nitfReadMeta(isnitf_meta, fields, fid);
end
function isnitf_meta = checkNicom(nicom, fid, isnitf_meta)
% Parse the Image Comment fields in the image subheader
% The length of the ICOM field is 80.
for currentComment = 1:nicom
%Pull the Image Comment
fields = {'ICOM%1d', 'ImageComment%1d', 80};
isnitf_meta = nitfReadMetaMulti(isnitf_meta, fields, fid, currentComment);
end
function tf = hasDataMaskTable(IC)
switch (IC)
case {'NM', 'M1', 'M3', 'M4', 'M5'}
tf = true;
otherwise
tf = false;
end
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