Evince hyperspectral file format

Description of hyperspectral file format

This document contains a short description of the default file format the Evince software use to save and load hyper/multi-spectral data cubs.

The format has its origin from a format called ENVI, but only part of the format is required.

The format consists of two files. One header file with the extension .hdr and one binary file with the extension .raw. For example measurement.hdr and measurement.raw.

Header file specification

The required parts that must be in the header file are specified below:

description
- Description of the header file.
file type
- Should always be ENVI.
interleave
- Refers to whether the data are BSQ, BIP, or BIL (default).
samples
- The number of samples (pixels) per image line for each band.
lines
- The number of bands per images file.
bands
- The number of bands per image file.
default bands
- Red, green, and blue default bands for visualization.
data type
- The type of data representation:
  - 8-bit byte
  - 16-bit
  - 32-bit signed long integer
  - 32-bit floating-point
  - 64-bit double-precision floating-point
  - 2x32-bit complex, real-imaginary pair of double-precision
  - 2x64-bit double-precision complex, real-imaginary pair of double-precision
  - 16-bit unsigned integer
  - 32-bit unsigned long integer
  - 64-bit signed long integer
  - 64-bit unsigned long integer
byte order
- The order of bytes in integer, long integer, 64-bit integer, unsigned 64-bit integer, floating-point, double precision, and complex data types. Use one of the following:
  - Byte order = 0 (Host(Intel) in the header info dialog) the least significant byte first (LSF) data (DEC and MS-DOS systems).
  - Byte order = 1 (Network(IEEE) in the header info dialog) the most significant byte first (MFS) data (all other platforms).
wavelength
- List the center wavelength values of each band in an image.

Example of header file

measurement.hdr

CODE

ENVI
description = { 
  Prediktera - Breeze Runtime
  Date = 2022-09-08 15:57:45:8572
  Camera name = HySpex SDK
  Camera type = SWIR_640_SN7514
  Camera id = 0
  Integration time = 1187
  Temperature = -98.127
 }
file type = ENVI

interleave = BIL
samples = 640
lines   = 1085
bands   = 362
default bands = {200, 80, 25}
header offset = 0
data type = 12
byte order = 0

errors = {none}

Wavelength = {
958.2745529519923,
962.5266490424583,
966.7787451329243,
971.0308412233904,
975.2829373138565,
979.5350334043225,
983.7871294947885,
988.0392255852545,
992.2913216757205,
996.5434177661865,
1000.7955138566526,
1005.0476099471186,
1009.2997060375847,
1013.5518021280507,
1017.8038982185167,
1022.0559943089827,
1026.3080903994487,
1030.5601864899147,
1034.812282580381,
1039.064378670847,
1043.316474761313,
1047.568570851779,
1051.820666942245,
1056.072763032711,
1060.324859123177,
1064.576955213643,
1068.829051304109,
1073.081147394575,
1077.333243485041,
1081.585339575507,
1085.837435665973,
1090.089531756439,
1094.3416278469053,
1098.5937239373714,
1102.8458200278374,
1107.0979161183034,
1111.3500122087694,
1115.6021082992354,
1119.8542043897014,
1124.1063004801674,
1128.3583965706334,
1132.6104926610994,
1136.8625887515655,
1141.1146848420317,
1145.3667809324977,
1149.6188770229637,
1153.8709731134297,
1158.1230692038957,
1162.3751652943618,
1166.6272613848278,
1170.8793574752938,
1175.1314535657598,
1179.3835496562258,
1183.6356457466918,
1187.887741837158,
1192.1398379276238,
1196.39193401809,
1200.644030108556,
1204.896126199022,
1209.148222289488,
1213.4003183799541,
1217.6524144704201,
1221.9045105608861,
1226.1566066513521,
1230.4087027418182,
1234.6607988322844,
1238.9128949227502,
1243.1649910132164,
1247.4170871036824,
1251.6691831941484,
1255.9212792846145,
1260.1733753750805,
1264.4254714655465,
1268.6775675560125,
1272.9296636464785,
1277.1817597369445,
1281.4338558274105,
1285.6859519178765,
1289.9380480083428,
1294.1901440988088,
1298.4422401892748,
1302.6943362797408,
1306.9464323702068,
1311.1985284606728,
1315.4506245511388,
1319.7027206416049,
1323.9548167320709,
1328.2069128225369,
1332.459008913003,
1336.711105003469,
1340.9632010939351,
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1349.4673932748672,
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1477.030275988848,
1481.282372079314,
1485.53446816978,
1489.786564260246,
1494.0386603507122,
1498.2907564411782,
1502.5428525316443,
1506.7949486221103,
1511.0470447125763,
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1528.0554290744403,
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1536.5596212553723,
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1549.3159095267706,
1553.5680056172366,
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1562.0721977981686,
1566.3242938886347,
1570.5763899791007,
1574.8284860695667,
1579.0805821600327,
1583.3326782504987,
1587.5847743409647,
1591.8368704314307,
1596.088966521897,
1600.341062612363,
1604.593158702829,
1608.845254793295,
1613.097350883761,
1617.349446974227,
1621.601543064693,
1625.853639155159,
1630.105735245625,
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1638.609927426557,
1642.8620235170233,
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1651.3662156979553,
1655.6183117884214,
1659.8704078788874,
1664.1225039693534,
1668.3746000598194,
1672.6266961502854,
1676.8787922407514,
1681.1308883312174,
1685.3829844216834,
1689.6350805121497,
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1702.3913687835477,
1706.6434648740137,
1710.8955609644797,
1715.1476570549457,
1719.3997531454118,
1723.6518492358778,
1727.9039453263438,
1732.1560414168098,
1736.4081375072758,
1740.6602335977418,
1744.912329688208,
1749.164425778674,
1753.41652186914,
1757.668617959606,
1761.920714050072,
1766.172810140538,
1770.4249062310041,
1774.6770023214701,
1778.9290984119361,
1783.1811945024021,
1787.4332905928682,
1791.6853866833342,
1795.9374827738002,
1800.1895788642664,
1804.4416749547324,
1808.6937710451984,
1812.9458671356645,
1817.1979632261305,
1821.4500593165965,
1825.7021554070625,
1829.9542514975285,
1834.2063475879945,
1838.4584436784608,
1842.7105397689265,
1846.9626358593928,
1851.2147319498586,
1855.4668280403248,
1859.7189241307908,
1863.9710202212568,
1868.2231163117228,
1872.4752124021888,
1876.7273084926549,
1880.9794045831209,
1885.2315006735869,
1889.483596764053,
1893.7356928545191,
1897.9877889449851,
1902.2398850354512,
1906.4919811259172,
1910.7440772163832,
1914.9961733068492,
1919.2482693973152,
1923.5003654877812,
1927.7524615782472,
1932.0045576687132,
1936.2566537591792,
1940.5087498496455,
1944.7608459401113,
1949.0129420305775,
1953.2650381210435,
1957.5171342115095,
1961.7692303019755,
1966.0213263924416,
1970.2734224829076,
1974.5255185733736,
1978.7776146638396,
1983.0297107543056,
1987.2818068447716,
1991.5339029352376,
1995.7859990257036,
2000.0380951161699,
2004.2901912066359,
2008.542287297102,
2012.794383387568,
2017.046479478034,
2021.2985755685,
2025.550671658966,
2029.802767749432,
2034.054863839898,
2038.306959930364,
2042.55905602083,
2046.811152111296,
2051.0632482017622,
2055.315344292228,
2059.5674403826943,
2063.81953647316,
2068.0716325636263,
2072.3237286540925,
2076.5758247445583,
2080.827920835024,
2085.0800169254903,
2089.3321130159566,
2093.5842091064223,
2097.8363051968886,
2102.0884012873544,
2106.3404973778206,
2110.5925934682864,
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2119.096785649219,
2123.3488817396847,
2127.600977830151,
2131.8530739206167,
2136.105170011083,
2140.3572661015487,
2144.609362192015,
2148.8614582824807,
2153.113554372947,
2157.3656504634127,
2161.617746553879,
2165.869842644345,
2170.121938734811,
2174.374034825277,
2178.626130915743,
2182.8782270062093,
2187.130323096675,
2191.3824191871413,
2195.634515277607,
2199.8866113680733,
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2208.3908035490053,
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2229.6512840013356,
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2289.18062926786,
2293.432725358326,
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2301.936917539258,
2306.1890136297243,
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2323.1973979915883,
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2335.953686262986,
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2472.020761157899,
2476.272857248365,
2480.5249533388314,
2484.777049429297,
2489.0291455197635,
2493.2812416102292
}

Binary file specification

The binary file format is written using one of the data types specified in the header file. How the data is stored is depending on the interleave flag. Prediktera uses the interleave BIL as default which stores one frame (Sample * bands) after each other (lines).