The compression rate of on board EIS data may vary depending on a few factors such as the observing target (QS, AR, CH, etc), slit/slot selection, exposures, etc.

The purpose of this study is trying to investigate how different compression schemes effect EIS data volume on board and work out a better estimation of compression rate for compression scheme (eg. DPCM, JPEG98, JPEG95, etc.)

The approach:

1. to get actual data volume from MDP status information: the inclined curve means data packets from EIS on MDP, the vertical curve means data packets dumped to ground station. So in general, known a raster's start and end time can calculate actual data volume, and then compare it with the designed data volume of this raster to get data compression rate.

[{Image src='images/factor/dataVolume_eis.png}]

2. to get related information from planning database/eis catalogue/fits header, for example: raster ID, compression scheme, designed data volume, SCI_OBJ, TARGET, slit/slot, exposures, etc.

3. prepare plots based on various factor combinations: compression rate vs. slit/slot, rate vs. target, rate vs. exposures



----

Some preliminary results (plots):\\

(The investigation here is for dates between %%(color:#cc0000;)2007-Sep-15 and 2007-Dec-15%%, as EIS is operationally stable over this duration.)



%%tabbedSection
%%tab-DPCM
%%(text-align:center)
!DPCM compression (all samples) 
%%

[{Image src='images/factor/dpcm/DPCM_only.gif}]

%%(text-align:center)
!DPCM compression vs different target
%%

DPCM vs. QS

[{Image src='images/factor/dpcm/DPCM_QS_only.gif}]

DPCM vs. AR

[{Image src='images/factor/dpcm/DPCM_AR_only.gif}]

DPCM vs. CH

[{Image src='images/factor/dpcm/DPCM_CH_only.gif}]

DPCM vs. PCH

[{Image src='images/factor/dpcm/DPCM_PCH_only.gif}]

DPCM vs. FIL

[{Image src='images/factor/dpcm/DPCM_FIL_only.gif}]

%%(text-align:center)
!DPCM compression vs different exposures
%%

DPCM vs. 10 second

[{Image src='images/factor/dpcm/DPCM_10s_only.gif}]

DPCM vs. 15 second

[{Image src='images/factor/dpcm/DPCM_15s_only.gif}]

DPCM vs. 20 second

[{Image src='images/factor/dpcm/DPCM_20s_only.gif}]

DPCM vs. 30 second

[{Image src='images/factor/dpcm/DPCM_30s_only.gif}]

DPCM vs. 60s second

[{Image src='images/factor/dpcm/DPCM_60s_only.gif}]

%%(text-align:center)
!DPCM compression vs SLA selection
%%

DPCM vs. 1" slit

[{Image src='images/factor/dpcm/DPCM_1arcsec_only.gif}]

DPCM vs. 2" slit

[{Image src='images/factor/dpcm/DPCM_2arcsec_only.gif}]

DPCM vs. 40" slit

[{Image src='images/factor/dpcm/DPCM_1arcsec_only.gif}]

DPCM vs. 266" slit

[{Image src='images/factor/dpcm/DPCM_266arcsec_only.gif}]


%%(text-align:center)
!DPCM compression vs SLA selection
%%


%%
%%tab-SecondTab
This is the second tab
%%
%%tab-ThirdTab
This is the third tab
%%
%%

[{Image src='images/factor/75/JPEG75_only.gif'}]


QS	QS,DC	QS,SYN	QS,CH   QS,NET	QS,DC,XBP	QS,SYN,DC       QS,DC,SEI       QS,PCH

XBP,QS

AR      AR,LMB          AR,EFR          AR,PLG  AR,CH   AR,NFL  AR,CH,LMB

SYN     SYN,DC          SYN,QS,DC

PCH     PCH,LMB,JET     PCH,JET

JET,LMB,PCH

LMB     LMB,LO          LMB,PCH,SPI     LMB,SPI

ENG,LMB,JET,PCH         ENG,QS,DC

SYN,DC,QS       SYN,DC

CH      CH,JET          CH,XBP          CH,DC   CH,LMB          CH,QS           CH,XBP,JET,EFR          CH,BP,JET

PR      PR,LMB          PP,PCH

SPI,LMB

EFR     SEI,EFR

DC      DC,LMB          WAV     NET

SPI     SPI,CH

BP,CH,JET       BP,JET

FIL,PR          FIL,QS