CASI

The Compact Airborne Spectrographic Imager (CASI) is a multispectral sensor that operates over the visible and near infra-red spectral range. It was retired from service at the end of the 2007 season. For more technical information on the sensor see the ARSF operations page at ​http://arsf.nerc.ac.uk/instruments/casi.asp

Spectral response

This document describes how to calculate the spectral response from ARSF processed CASI data.

Raw data format

The CASI format is apparently internal to ITRES. A scan of files here indicates a header made up of NULL terminated strings, with the first bytes being "CasiFileHeader".

caha001.166    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha002.166    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha003.166    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha004.166    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha010.254    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha011.254    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha012.254    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha013.254    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|
caha014.254    00000000  43 61 73 69 46 69 6c 65  48 65 61 64 65 72 00 53  |CasiFileHeader.S|

There's a lot more strings afterwards, as shown below with NULLs converted to newlines. Following this there appears to be raw data frames of some kind.

CasiFileHeader
SerialNumber 2007
Version  5d.03oAlphaR$
FrameHeaderLength 128
Date 2007 06 15
Time 10 51 50 697
Mode 0
IntegrationTime 22 22
FILE 1
SpectralConfig 142 1 0 256 19712 20 1 1 288
ExtraLooks 3
SpatialConfig 16 289 299 258 268 237 246 206 211 176 182 155 158 144 148 128 132 123 127 107 111 103 106 97 99 87 90 66 70 43 47 4 8 19712 20
MaxRows 288
MaxColumns 612
Calibration 1
G0 949.889
G1 -1.9708
G2 0.000313512
G3 -3.67271e-007
SERIAL  2007
PACK 0
DataOffset 80
ILS 35
DarkOffset 20
SLColumns 11
ScatteredLight 50
ElectronicOffset 7
IGD 100
GPPF 0
FGDI 0
IGS 1
GPW 5
THRUPUT 0.000000
VARFRAME 0
STANDBY 0
FILEHEAD 1024
CCDCOLS 612
CCDROWS 288
CCDSTORE 290
MCUCLK 4.096000e+006
APERTURE 1
NOISESAMPLE 100
POSTGUARD 0
PREGUARD 1
SUMGUARD 0
PREREAD 3
NUMACTIVEROWS 1
MCUFILE stdclk05.bin
CALFILE CAL1042
HYPERFILE HYP400
DSPPGM icmosd07.bin
CLKADD iniclk05.bin
CCDPARM init04.bin
DARKFRAMES 200
UNIFRAMES 0
ITSAMPLE 10
ATTITUDE 3
PIXEL 16
BSPGPSBAUD 19200
BSPALTBAUD 0
PPFRM 0
FOV 54.400000
SYNCDEV 2
GPS NONE