--- /dev/null
+## Copyright (C) 2009 Roderick Koehle koehle(at)users.sourceforge.net
+##
+## This program is free software; you can redistribute it and/or
+## modify it under the terms of the GNU General Public License
+## as published by the Free Software Foundation; either version 2
+## of the License, or (at your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING. If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{exif} =} readexif(@var{filename}, @var{thumbnail})
+## Read EXIF information from JPEG image data.
+##
+## The exif tag information are returned in the @var{exif} data structure.
+## Integer ratios are expressed as column vector.
+## For example, a focal number of 2.8 is expressed
+## as FNumber=[28; 10]. Otherwise all data are returned by the type
+## as specified in the IFD structures.
+##
+## The filename for the thumbnail image is optional.
+## If given, the thumbnail jpeg image will be stored to
+## file @var{thumbnail}.
+##
+## Reference:
+## JEITA CP-3451, Exchangeable image file format for digital still cameras:
+## Exif Version 2.2
+##
+## @seealso{imwrite, imfinfo}
+## @end deftypefn
+
+function exif = readexif(file, thumbnail)
+
+ % Enable the debug flag to see more of the JPG sections.
+
+ debug = false;
+
+ in = fopen(file);
+ if (in<0)
+ error('File "%s" not found !', file);
+ end
+
+ s = fread(in, 1, 'uint16', 'ieee-be');
+
+ JPEG.SOI = 0xffd8;
+ JPEG.APP0 = 0xffe0;
+ JPEG.APP1 = 0xffe1;
+ JPEG.APP2 = 0xffe2;
+ JPEG.DQT = 0xffdb;
+ JPEG.DHT = 0xffc4;
+ JPEG.DRI = 0xffdd;
+ JPEG.SOF = 0xffc0;
+ JPEG.SOS = 0xffda;
+ JPEG.EOI = 0xffd9;
+
+ % Stop if no Start of Image found
+
+ if s~=JPEG.SOI
+ error('JPEG Format error - missing start of image tag.');
+ end
+
+ exif = [];
+
+ while ~feof(in)
+ s = fread(in, 1, 'uint16', 'ieee-be');
+
+ switch s
+ case JPEG.SOI
+ case JPEG.APP0
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ if debug, printf('APP0: %i\n', l); end
+ fseek(in, l-2, 'cof');
+ case JPEG.APP1
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ if debug, printf('APP1: %i\n', l); end
+ app1 = fread(in, l-2, 'uchar');
+ if nargin==1
+ exif = parseexif(app1);
+ else
+ exif = parseexif(app1, thumbnail);
+ end
+ % stop reading further, remove following break
+ % if you want to extend this parser.
+ break;
+ case JPEG.APP2
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ if debug, printf('APP2: %i\n', l); end
+ fseek(in, l-2, 'cof');
+ case JPEG.DQT % define quantization table
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ if debug, printf('DQT: %i\n', l); end;
+ fseek(in, l-2, 'cof');
+ case JPEG.DHT % define huffmann table
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ fseek(in, l-2, 'cof');
+ if debug, printf('DHT: %i\n', l); end
+ case JPEG.DRI % define restart interoperability
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ fseek(in, l-2, 'cof');
+ if debug, printf('DRI: %i\n', l); end
+ case JPEG.SOF % start of frame
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ fseek(in, l-2, 'cof');
+ if debug, printf('SOF: %i\n', l); end
+ case JPEG.SOS % start of scan
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ fseek(in, l-2, 'cof');
+ if debug, printf('SOS: %i\n', l); end
+
+ % JPEG compressed data comes here ...
+ break;
+
+ case JPEG.EOI % end of image
+ printf('EOI');
+ otherwise % Skip unknown tags
+ l = fread(in, 1, 'uint16', 'ieee-be');
+ if debug, printf('TAG %04X: %i\n', s, l); end
+ fseek(in, l-2, 'cof');
+ end
+ end
+
+ fclose(in);
+end
+
+%
+% Parse EXIF APP1 section
+%
+% This routine will parse the APP1 section of an jpeg image.
+% If a filename "thumb" is given, the tumbnail image data
+% will be exported to given file.
+%
+% exif = parseexif(data, thumb)
+%
+function exif = parseexif(data, thumb)
+
+ id = char(data(1:6).');
+ if strncmp(id, ['Exif' 0 0], 6)
+
+ % TIFF header
+
+ byteorder = char(data(7:8).');
+ littleendian = strncmp(byteorder, 'II', 2);
+ bigendian = strncmp(byteorder, 'MM', 2);
+
+ tag42 = intn(data(9:10), bigendian);
+ offset = intn(data(11:14), bigendian);
+
+ if (~littleendian && ~bigendian) || tag42~=42
+ error('invalid TIFF header');
+ end
+
+ % IFD fields
+
+ exif = ifdparse(tifftags(), data, offset, bigendian);
+ else
+ exif = [];
+ end
+
+ % export thumbnail image
+
+ if nargin==2 && isfield(exif, 'JPEGInterchangeFormat')
+ i = exif.JPEGInterchangeFormat;
+ n = exif.JPEGInterchangeFormatLength;
+
+ jpg = data(7+i:7+i+n-1);
+ out = fopen(thumb, 'w');
+ if (out<0),
+ error('Cannot open file "%s" for writing thumbnail image.', thumb);
+ end
+ fwrite(out, jpg, 'uint8');
+ fclose(out);
+ end
+end
+
+function ifd = ifdparse(dict, data, offset, endian)
+
+ debug = false;
+
+ ifd = [];
+
+ while offset
+ ifd_fields = intn(data(7+offset+(0:1)), endian);
+
+ if debug, printf('Tag Type Count Offset\n'); end
+ for i=1:ifd_fields
+ j = 9+offset+(i-1)*12;
+ ifd_tag = intn(data( j:j+1), endian);
+ ifd_type = intn(data(j+2:j+3), endian);
+ ifd_count = intn(data(j+4:j+7), endian);
+ ifd_offset = intn(data(j+8:j+11), endian);
+
+ name = ifdtagname(dict, ifd_tag);
+
+ if debug,
+ printf('%04x %04x %08x %08x %s : ', ifd_tag, ifd_type, ...
+ ifd_count, ifd_offset, name);
+ end
+ if ifd_type>0
+ n = ifdsize(ifd_type);
+
+ if n*ifd_count<=4
+ value = data(j+8:j+8+n*ifd_count-1);
+ value = reshape(value, n, ifd_count);
+ else
+ a = 7+ifd_offset;
+ b = 7+ifd_offset+n*ifd_count-1;
+ if (a>0 && b>0 && a<=length(data) && b<=length(data))
+ value = data(7+ifd_offset:7+ifd_offset+n*ifd_count-1);
+ value = reshape(value, n, ifd_count);
+ else
+ value = [];
+ end
+ end
+ end
+
+ switch ifd_type
+ case 01 % unsigned char
+ ifd.(name) = uint8(value);
+ if debug,
+ printf('%02x ', uint8(value));
+ printf('\n');
+ end
+ case 02 % Ascii
+ ifd.(name) = char(value);
+ if debug, printf('%s\n', char(value)); end
+ case 03 % 16 bit unsigned int
+ ifd.(name) = uintn(value, endian);
+ if debug
+ printf('%i ', intn(value), endian);
+ printf('\n');
+ end
+ case 04 % 32 bit unsigned int
+ ifd.(name) = uintn(value, endian);
+ if debug, printf('%i\n', uintn(value, endian)); end
+ case 05 % 32 bit unsigned rational
+ ifd.(name) = [uintn(value(1:4,:), endian); uintn(value(5:8,:), endian)];
+ if debug, printf('%i/%i\n',uintn(value(1:4), endian),uintn(value(5:8)), endian); end
+ case 07 % unknown
+ ifd.(name) = uint8(value);
+ if debug
+ printf('%02x ', value);
+ printf('\n');
+ end
+ case 09 % 32 bit signed int
+ ifd.(name) = intn(value, endian);
+ if debug, printf('%i\n', intn(value, endian)); end
+ case 10 % 32 bit signed rational
+ ifd.(name) = [intn(value(1:4,:), endian); intn(value(5:8,:), endian)];
+ if debug, printf('%i/%i\n',intn(value(1:4), endian),intn(value(5:8)), endian); end
+ otherwise
+ printf('%02x ', value);
+ printf('\n');
+ end
+
+ switch ifd_tag
+ case 0x8769, % Exif Pointer
+ ifd.(name) = ifdparse(exiftags(), data, ifd_offset, endian);
+ case 0x8825, % GPS Pointer
+ ifd.(name) = ifdparse(gpstags(), data, ifd_offset, endian);
+ case 0xa005 % Interoperatibility Pointer
+ ifd.(name) = ifdparse(dict, data, ifd_offset, endian);
+% case 0x927c % Makernotes
+% ifd.(name) = ifdparse([], data, ifd_offset, endian);
+ otherwise
+ end
+ end
+ j = 9+offset+ifd_fields*12;
+ ifd_next = intn(data(j:j+3), endian);
+
+ offset = ifd_next;
+ end
+end
+
+%
+% Return bytelength for respective IFD type
+%
+function n = ifdsize(ifd_type)
+ switch ifd_type
+ case {1, 2, 7}, n = 1;
+ case 03 , n = 2;
+ case {4, 9} , n = 4;
+ case {5, 10} , n = 8;
+ otherwise , n = 1;
+ end
+end
+
+
+%
+% Convert little endian character vector to integer
+%
+function y = intn(x, bigendian)
+ if bigendian
+ y = polycol(x, int32(256));
+ else
+ y = polycol(flipud(x), int32(256));
+ end
+end
+
+function y = uintn(x, bigendian)
+ if bigendian
+ y = polycol(x, uint32(256));
+ else
+ y = polycol(flipud(x), uint32(256));
+ end
+end
+
+%
+% Use own polyval that works with integers,
+% it evaluates the number polygon columnwise.
+%
+% number = polycol(digits, base)
+%
+function y = polycol(c, x)
+ y = c(1,:);
+ for i=2:size(c, 1)
+ y = y.*x+c(i,:);
+ end
+end
+
+%
+% Query EXIF IFD tagname
+%
+% Unfortunately, neither MATLAB nor Octave provide a hash functionality,
+% so use structures as hash.
+%
+function name = ifdtagname(dict, key)
+ k = sprintf('K%04X', key);
+ if isfield(dict, k)
+ name = dict.(k);
+ else
+ name = sprintf('tag%04X', key);
+ end
+end
+
+%
+% Primary image IFD tags according to Exif 2.2
+%
+function dict = tifftags()
+ t = {
+
+ % TIFF Tags according to EXIF2.2, additional baseline TIFF tags are marked by a '%'
+
+ '0FE' 'NewSubfileType' %
+ '0FF' 'SubfileType' %
+ '100' 'ImageWidth'
+ '101' 'ImageLength'
+ '102' 'BitsPerSample'
+ '103' 'Compression'
+ '106' 'PhotometricInterpretation'
+ '108' 'CellWidth' %
+ '109' 'CellLength' %
+ '10A' 'FillOrder' %
+ '10E' 'ImageDescription'
+ '10F' 'Make'
+ '110' 'Model'
+ '111' 'StripOffsets'
+ '112' 'Orientation'
+ '115' 'SamplesPerPixel'
+ '116' 'RowsPerStrip'
+ '117' 'StripByteCounts'
+ '118' 'MinSampleValue' %
+ '119' 'MaxSampleValue' %
+ '11A' 'XResolution'
+ '11B' 'YResolution'
+ '11C' 'PlanarConfiguration'
+ '120' 'FreeOffsets' %
+ '121' 'FreeByteCounts' %
+ '122' 'GrayResponseUnit' %
+ '123' 'GrayResponseCurve' %
+ '128' 'ResolutionUnit'
+ '12D' 'TransferFunction'
+ '131' 'Software'
+ '132' 'DateTime'
+ '13B' 'Artist'
+ '13C' 'HostComputer' %
+ '13E' 'WhitePoint'
+ '13F' 'PrimaryChromaticities'
+ '140' 'ColorMap' %
+ '152' 'ExtraSamples' %
+ '201' 'JPEGInterchangeFormat'
+ '202' 'JPEGInterchangeFormatLength'
+ '211' 'YCbCrCoefficients'
+ '212' 'YCbCrSubSampling'
+ '213' 'YCbCrPositioning'
+ '214' 'ReferenceBlackWhite'
+ '8298' 'Copyright'
+ '8769' 'Exif IFD Pointer'
+ '8825' 'GPS Info IFD Pointer'
+ };
+
+ dict = [];
+ for i=1:size(t,1)
+ key = sprintf('K%04X', hex2dec(t{i,1}));
+ value = t{i,2};
+ dict.(key) = strrep(value, ' ', '_');
+ end
+end
+
+%
+% EXIF private tags
+%
+function dict = exiftags()
+ t = {
+
+ % EXIF Tags
+
+ '829A' 'ExposureTime'
+ '829D' 'FNumber'
+ '8822' 'ExposureProgram'
+ '8824' 'SpectralSensitivity'
+ '8827' 'ISOSpeedRatings'
+ '8828' 'OECF'
+ '9000' 'ExifVersion'
+ '9003' 'DateTimeOriginal'
+ '9004' 'DateTimeDigitized'
+ '9101' 'ComponentsConfiguration'
+ '9102' 'CompressedBitsPerPixel'
+ '9201' 'ShutterSpeedValue'
+ '9202' 'ApertureValue'
+ '9203' 'BrightnessValue'
+ '9204' 'ExposureBiasValue'
+ '9205' 'MaxApertureValue'
+ '9206' 'SubjectDistance'
+ '9207' 'MeteringMode'
+ '9208' 'LightSource'
+ '9209' 'Flash'
+ '920A' 'FocalLength'
+ '9214' 'SubjectArea'
+ '927C' 'MakerNote'
+ '9286' 'UserComment'
+ '9290' 'SubsecTime'
+ '9291' 'SubsecTimeOriginal'
+ '9292' 'SubsecTimeDigitized'
+ 'A000' 'FlashpixVersion'
+ 'A001' 'ColorSpace'
+ 'A002' 'PixelXDimension'
+ 'A003' 'PixelYDimension'
+ 'A004' 'RelatedSoundFile'
+ 'A005' 'Interoperatibility IFD Pointer'
+ 'A20B' 'FlashEnergy'
+ 'A20C' 'SpatialFrequencyResponse'
+ 'A20E' 'FocalPlaneXResolution'
+ 'A20F' 'FocalPlaneYResolution'
+ 'A210' 'FocalPlaneResolutionUnit'
+ 'A214' 'SubjectLocation'
+ 'A215' 'ExposureIndex'
+ 'A217' 'SensingMethod'
+ 'A300' 'FileSource'
+ 'A301' 'SceneType'
+ 'A302' 'CFAPattern'
+ 'A401' 'CustomRendered'
+ 'A402' 'ExposureMode'
+ 'A403' 'WhiteBalance'
+ 'A404' 'DigitalZoomRatio'
+ 'A405' 'FocalLengthIn35mmFilm'
+ 'A406' 'SceneCaptureType'
+ 'A407' 'GainControl'
+ 'A408' 'Contrast'
+ 'A409' 'Saturation'
+ 'A40A' 'Sharpness'
+ 'A40B' 'DeviceSettingDescription'
+ 'A40C' 'SubjectDistanceRange'
+ 'A420' 'ImageUniqueID'
+
+ % Interoperatibility tags
+
+ '001' 'InteroperatibilityIndex'
+ '002' 'InteroperatibilityVersion'
+ '1000' 'RelatedImageFileFormat'
+ '1001' 'RelatedImageWidth'
+ '1002' 'RelatedImageLength'
+ };
+
+ dict = [];
+ for i=1:size(t,1)
+ key = sprintf('K%04X', hex2dec(t{i,1}));
+ value = t{i,2};
+ dict.(key) = strrep(value, ' ', '_');
+ end
+end
+
+%
+% EXIF GPS tags
+%
+function dict = gpstags()
+ t = {
+ 0 'GPSVersionID'
+ 1 'GPSLatitudeRef'
+ 2 'GPSLatitude'
+ 3 'GPSLongitudeRef'
+ 4 'GPSLongitude'
+ 5 'GPSAltitudeRef'
+ 6 'GPSAltitude'
+ 7 'GPSTimeStamp'
+ 8 'GPSSatellites'
+ 9 'GPSStatus'
+ 10 'GPSMeasureMode'
+ 11 'GPSDOP'
+ 12 'GPSSpeedRef'
+ 13 'GPSSpeed'
+ 14 'GPSTrackRef'
+ 15 'GPSTrack'
+ 16 'GPSImgDirectionRef'
+ 17 'GPSImgDirection'
+ 18 'GPSMapDatum'
+ 19 'GPSDestLatitudeRef'
+ 20 'GPSDestLatitude'
+ 21 'GPSDestLongitudeRef'
+ 22 'GPSDestLongitude'
+ 23 'GPSDestBearingRef'
+ 24 'GPSDestBearing'
+ 25 'GPSDestDistanceRef'
+ 26 'GPSDestDistance'
+ };
+
+ dict = [];
+ for i=1:size(t,1)
+ key = sprintf('K%04X', t{i,1});
+ value = t{i,2};
+ dict.(key) = strrep(value, ' ', '_');
+ end
+end
+
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff