HICO
Hyperspectral Imager for the Coastal Ocean aboard the ISS

images courtesy of Oregon State University
   
28 narrow wavebands
BAND    1        2        3        4        5        6        7        8        9       10      11      12      13      14      15      16      17      18      19      20      21      22      23      24      25      26      27       28   
WL         406.9 418.4 429.9 441.3 452.8 464.2 475.7 487.1 498.6 510.0 521.5 533.0 544.4 555.9 567.3 578.8 590.2 601.7 613.2 624.6 636.1 647.5 659.0 670.4 681.9 693.3 PAN  842.3


 
1 - NO NEED for field data, nor for atmospheric correction
2 - this is demonstrated in this website, using a variety of hyper/multi spectral data
 
Requirements are
1 - homogeneous water body and atmosphere
2 - some coverage of optically deep water
3 - some coverage of dry land
 
Problems are
1 - the precision on estimated depth is found wanting, because the noise-equivalent change in radiance  of accessible data is too high for shallow water column correction work 
2 - radiance data should be preprocessed by the provider at level 1 in order to improve S/N ratio
3 - exponential decay: the deeper/darker the bottom, the poorer the performances
 
So
I keep digging
until suitable data
become available
 
Image preparation
  Optical calibration
home

 

HICO image preparation
  • I exported from OSU's ENVI format into PCIDSK format, using OpenEV
  • The image is in Level 1B, pixel size is 100 m, 500 columns, 2000 lines
  • I did not use the projection information provided
  • HICO is comprised of 87 raw bands, ~ 5 nm wide
  • presently, I can only manage 28 bands, in spite of my full HD screen display: see command line
  • So, I binned HICO raw bands as follows
WLMin[ 1]=401.2 WL[ 1]=406.9 WLMax[ 1]=412.7    by binning bands HICO_1 and HICO_2
WLMin[ 2]=412.7 WL[ 2]=418.4 WLMax[ 2]=424.1    by binning bands HICO_3 and HICO_4
WLMin[ 3]=424.1 WL[ 3]=429.9 WLMax[ 3]=435.6    ....
WLMin[ 4]=435.6 WL[ 4]=441.3 WLMax[ 4]=447.0    ....
WLMin[ 5]=447.1 WL[ 5]=452.8 WLMax[ 5]=458.5    ....
WLMin[ 6]=458.5 WL[ 6]=464.2 WLMax[ 6]=469.9    ....
WLMin[ 7]=470.0 WL[ 7]=475.7 WLMax[ 7]=481.4    ....
WLMin[ 8]=481.4 WL[ 8]=487.1 WLMax[ 8]=492.9    ....
WLMin[ 9]=492.9 WL[ 9]=498.6 WLMax[ 9]=504.3    ....
WLMin[10]=504.3 WL[10]=510.0 WLMax[10]=515.8    ....

WLMin[11]=515.8 WL[11]=521.5 WLMax[11]=527.2    ....
WLMin[12]=527.2 WL[12]=533.0 WLMax[12]=538.7    ....
WLMin[13]=538.7 WL[13]=544.4 WLMax[13]=550.1    ....
WLMin[14]=550.2 WL[14]=555.9 WLMax[14]=561.6    ....
WLMin[15]=561.6 WL[15]=567.3 WLMax[15]=573.0    ....
WLMin[16]=573.1 WL[16]=578.8 WLMax[16]=584.5    ....
WLMin[17]=584.5 WL[17]=590.2 WLMax[17]=596.0    ....
WLMin[18]=596.0 WL[18]=601.7 WLMax[18]=607.4    ....
WLMin[19]=607.4 WL[19]=613.2 WLMax[19]=618.9    ....
WLMin[20]=618.9 WL[20]=624.6 WLMax[20]=630.3    ....

WLMin[21]=630.4 WL[21]=636.1 WLMax[21]=641.8    ....
WLMin[22]=641.8 WL[22]=647.5 WLMax[22]=653.2    ....
WLMin[23]=653.3 WL[23]=659.0 WLMax[23]=664.7    ....
WLMin[24]=664.7 WL[24]=670.4 WLMax[24]=676.1    ....
WLMin[25]=676.2 WL[25]=681.9 WLMax[25]=687.6    ....

WLMin[26]=687.6 WL[26]=693.3 WLMax[26]=699.1   by binning bands HICO_51 and HICO_52
WLMin[27]=699.1 WL[27]=704.8 WLMax[27]=710.5   this is a synthetic Panchromatic band
WLMin[28]=836.6 WL[28]=842.3 WLMax[28]=848.0   by binning bands HICO_77 and HICO_78

The 4SM synthetic panchromatic band was prepared
by binning bands 4SM-7 to 4SM-25
WLMin[ 7]=470.0 WL[ 7]=475.7 WLMax[ 7]=481.4    ....
WLMin[ 8]=481.4 WL[ 8]=487.1 WLMax[ 8]=492.9    ....
WLMin[ 9]=492.9 WL[ 9]=498.6 WLMax[ 9]=504.3    ....
WLMin[10]=504.3 WL[10]=510.0 WLMax[10]=515.8    ....
WLMin[11]=515.8 WL[11]=521.5 WLMax[11]=527.2    ....
WLMin[12]=527.2 WL[12]=533.0 WLMax[12]=538.7    ....
WLMin[13]=538.7 WL[13]=544.4 WLMax[13]=550.1    ....
WLMin[14]=550.2 WL[14]=555.9 WLMax[14]=561.6    ....
WLMin[15]=561.6 WL[15]=567.3 WLMax[15]=573.0    ....
WLMin[16]=573.1 WL[16]=578.8 WLMax[16]=584.5    ....
WLMin[17]=584.5 WL[17]=590.2 WLMax[17]=596.0    ....
WLMin[18]=596.0 WL[18]=601.7 WLMax[18]=607.4    ....
WLMin[19]=607.4 WL[19]=613.2 WLMax[19]=618.9    ....
WLMin[20]=618.9 WL[20]=624.6 WLMax[20]=630.3    ....
WLMin[21]=630.4 WL[21]=636.1 WLMax[21]=641.8    ....
WLMin[22]=641.8 WL[22]=647.5 WLMax[22]=653.2    ....
WLMin[23]=653.3 WL[23]=659.0 WLMax[23]=664.7    ....
WLMin[24]=664.7 WL[24]=670.4 WLMax[24]=676.1    ....
WLMin[25]=676.2 WL[25]=681.9 WLMax[25]=687.6    ....
So, for 4SM, my database.pix 16U image database has 28 raw data bands, ~10 nm wide
  • Blue        is band_7
  • Green     is band_13
  • Red         is band_22
  • Panchro is band_27
  • NIR         is band_28
HICO images are not georeferenced.
 

Optical calibration

This by large benefitted from investigations conducted on HYPERION at Fakarava atoll
 



HICO at Lee Stocking Island
November image    
Results June versus November
June November

june
no tide correction
ARTIFACT: note the shoaling artifact
over the very dark seagrass area

november
no tide correction
Note the absence of a shoaling artifact
over the very dark seagrass area

 
 

june
no tide correction

november
no tide correction

 

 

 

 

 
These two LSI HICO scenes are not co-registered; so results may not be precisely compared.
As regards vegetation: one scene is taken in end spring, one in late autumn.
It takes very strict fine-tuning to obtain "reasonable" results.
I'm not allways sure what aspect of the "physics behind" such fiddling actually portends.

All this practise must be reviewed and investigated by competent accademic research.
But 4SM possibly is a viable alternative
to more complex semi-analytical approaches.