instrument development status and performances … · performances of hyperspectral imager suite...

INSTRUMENT DEVELOPMENT STATUS AND PERFORMANCES OF

HYPERSPECTRAL IMAGER SUITE (HISUI) -Onboard Data Correction-

Jun Tanii Japan Space Systems , Tokyo, Japan

Akira Iwasaki The University of Tokyo, Tokyo, Japan

Yoshiyuki Ito NEC Corporation, Tokyo, Japan

WE3.09.1 #2513

International Geoscience and Remote Sensing Symposium 2014 July 13th-18th, 2014 Québec, Canada

Table of Contents

1. HISUI (Hyperspectral Imager SUIte) Instrument Overview

2. Onboard Data Correction of Hyperspectral Sensor of HISUI

3. Conclusion

Hyperspectral Sensor Unit

HISUI (Hyperspectral Imager SUIte) ▐ HISUI (Hyperspectral Imager SUIte)

Japanese earth observation project for resource exploration, vegetation and environment monitoring

Follow-on mission of ASTER (Advanced Spaceborne Thermal Emission and reflection Radiometer) onboard TERRA

Consists of 2 instruments • Hyperspectral sensor (185 bands

from VIS to SWIR) • Multispectral sensor (4 bands of

VNIR)

HISUI (Hyperspectral Imaging SUIte)

=“jade” in Japanese

http://www.moonmadness.jp/itoigawahisui.html

Multispectral Sensor Unit

1. HISUI Instrument Overview

HISUI Specifications Instrument Hyperspectral sensor Multispectral sensor

VNIR SWIR Spatial Scanning Push broom type by satellite moving Same as left IFOV (Spatial resolution) 48.5 urad (30 m) 8.1 urad (5 m) FOV (swath width) 48.5 mrad (30 km) 144.7 mrad (90 km) Observation frequency < 4.36 ms < 0.73 ms Wavelength region and number of bands / Center wave length

400-970 nm (57 bands)

900-2500 nm (128 bands)

Band1:485 nm Band2:560 nm Band3:660 nm Band4:835 nm

Spectral resolution (sampling) for Hyper Spectral Band width for Multi

10 nm 12.5 nm Band1:70 nm Band2:80 nm Band3:60 nm Band4:110 nm

Spectral resolution (ILS FWHM) < 11 nm < 16 nm Same as band width Dynamic range Saturated at > 70% albedo Same as left SNR >450 (@620 nm) >300 (@2100 nm) > 200 (for each band) MTF >0.2 > 0.3 Smile and Keystone < 1 image pixel N/A Calibration accuracy (radiometric)

Absolute:±5%, Among bands:±2% Same as left

Calibration accuracy (spectral) < 0.2 nm < 0.625 nm N/A Quantization 12 bit Same as left Mission life 5 years Same as left


185 bands

HISUI Functional Block Diagram

VNIR Spectrometer

SWIR Spectrometer

VNIR Detector

SWIR Detector

SWIR Cooling Unit

VNIR Signal

Processor

SWIR Signal

Processor

Power Supply Calibration Unit

Hyper Electronics Unit(HELU)

Fore optics

Fore optics Detector Signal Processor

Calibration Unit Power Supply

Multi Electronics Unit(MELU)

Hyperspectral Imager

Multispectral Imager


Function of Onboard Data Correction

HISUI Hyperspectral Sensor Function Diagram

VNIR Signal processor(VSP)

SWIR AnalogueSignal Processor

(SASP)

HYPER electronicsunit (HELU)

Hyper-spectral scanning radiometer unit（HSRU）

VNIR science signal

Hyper-spectral scanningradiometer sub-system（HSRS）

SWIR science signal

Hyper Spectral Sensor System (HISUI) 1553B Bus

Telemetry&Commandinterface

Primary Power supply

Control unit (ＣＮＴ）

HYPERheater control

electronics (HHCE)

HYPERheater control

electronics (MHCE)

Cooler controlelectronics (CCE)

HYPER calibrationelectronics(HＣＡＬE)

Telescope SW

IRspectro-graph

VN

IRspectro-graph

VW

IRD

etectorS

WIR

Detector

Halogenlam

p+ filter

Lightfrom

the Earth

MULTI calibrationelectronics(MＣＡＬE)


CNT

VNIR/SWIR Spectrographs

VNIR/SWIR Detectors Observing Light

VNIR/SWIR Signal Processors

Telescope

Electronics Unit

Hyperspectral Sensor Unit

7

Optical Calibrator

Telescope (TMA)

Slit

VNIR Grating Spectrometer

(Offner)

SWIR Grating Spectrometer

(Offner)

Si-CMOS 2D-Detector

MCT 2D-Detector

Stirling Cooler


Design of Hyperspectral Sensor Unit

▐ Design for The Telescope and Spectrograph Telescope

TMA ( off-axis three mirror anastigmat type ) • The diameter of telescope is approximately 30cm and the F-number is 2.2. It is matched for the ground sampling distance(GSD) of 30 meters.

Spectrograph Two Aberration-corrected Offner type Grating spectrographs VNIR spectrograph and SWIR spectrograph High diffraction efficiency Equal interval of Spectral Sampling Minimize the wavelength shift/ smile/ keystone Robust in alignment against temperature change Stable temperature control within +/-1K in orbit to minimize the

wavelength shift.


▐ Design for The Telescope and Spectrograph Detector

• VNIR detector: 2Dimentional backside illuminated silicon CMOS • SWIR detector: 2Dimentional PV-MCT

• Cooler and Dewar • SWIR detector is integrated inside the dewar • and cooled down to 145K using Stirling-type cryocooler.

Design of Hyperspectral Sensor Unit 1. HISUI Instrument Overview

Flight Model of Hyperspectral Sensor Unit

10

Optical Calibrator

Telescope (TMA)

Slit

VNIR Grating Spectrometer

(Offner)

SWIR Grating Spectrometer

(Offner)

Si-CMOS 2D-Detector MCT

2D-Detector

Stirling Cooler


Onboard Data Correction and Compression

▐ Function of HELU (Hyper Electronics Unit) for Digital Data Data correction of items as follows;

• Offset-Gain-Non linearity • PRNU (Photo Response Non-Uniformity) • Smile distortion (using weight-coefficients during the binning)

In order to reduce data size, • data binning in spectral direction 4 pixels in VNIR 2 pixels in SWIR • lossless data compression

Observation Mode: With Onboard Data Correction and Data Compression Calibration Mode: Without Onboard Data Correction nor Data Compression ( Onboard Calibration with Lamps, Vicarious Calibration, ……)

2. Onboard Data Correction

Flow of Onboard Data Correction in HELU



Onboard Radiometric Correction

Radiance：W（W/m2/sr/μm）

Raw Data of Detector pixel ：X （DN）

Calculation formula 1W = A(X-C)^2 +B(X-C)

Calculation formula 2W = A(X-C)^2 +B(X-C)•For low response pixel• For low radiance band

Calculation formula 3W = A1X+B1, W=A2(X-C-50)*for bad linearity pixel

Offset

2 3

1

Formulae for non Linearity/Offset Correction


Onboard Radiometric Correction Examples of PRNU/Gain Correction

0.910.920.930.940.950.960.970.980.99

11.01

0 128 256 384 512 640 768 896 1024

PRNU

(%)

Pixel No.

VNIR PRNU

Band9

Band16

Band22

Band26

Band42

0.910.920.930.940.950.960.970.980.99

11.01

0 125 250 375 500 625 750 875 1000

PRNU

Pixel No.

SWIR PRNU

Band60

Band97

Band108

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

0 128 256 384 512 640 768 896 1024

VNIR

PRNU

Pixel No.

VNIR PRNU

PRNU 485nmPRNU 555nmPRNU 615nmPRNU 655nmPRNU 835nm

0.830.840.850.860.870.880.89

0.90.910.920.930.940.950.960.970.980.99

11.01

0 125 250 375 500 625 750 875 1000

PRNU

Pixel No.

SWIR PRNU

Band60Band97Baqnd108

VNIR SWIR

Raw Data

Corrected Data

34%

8%

16%

3%

Detector pixel No

PRNU

PRNU: Photo Response Non-Uniformity

(*) Based on the data of Evaluation Model of the sensor


Onboard Spectral Correction Concept of Binning/Smile Correction



Onboard Spectral Correction

2,096.249995 2,096.249996 2,096.249997 2,096.249998 2,096.249999 2,096.250000 2,096.250001 2,096.250002 2,096.250003 2,096.250004 2,096.250005

0 125 250 375 500 625 750 875 1000

Wav

elen

gth （

nm）

Pixel No.

Ditale of center of wavelength (Band22 @ SWIR)

Band97 with smile correction

614.999995 614.999996 614.999997 614.999998 614.999999 615.000000 615.000001 615.000002 615.000003 615.000004 615.000005

0 128 256 384 512 640 768 896 1024

Wav

elen

gth （

nm）

Pixel No.

Ditale of center of wavelength (Band22 @ VNIR)


<0.00001nm

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0 125 250 375 500 625 750 875 1000Dist

ance

from

Aver

age

posit

rion (

Imag

e Pixe

ls)

Pixel Number (CT direction)

Performance of Smile Characterization in VNIR region of HISUI

635nm

770nm

940nm

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0 125 250 375 500 625 750 875 1000

Dist

ance

from

Aver

age

posit

ion

（im

age p

ixels）

Pixel Number ( CT direction)

Performance of Smile Characterization in SWIR region of HISUI

940nm

1215nm

1590nm

1775nm

<0.00001nm

<1nm <2.5nm

VNIR SWIR

Corrected Data

Spectral Channel No

CenterWavelength

Before Smile Correction

Examples of Binning/Smile Correction



Onboard Spectral Correction Concept of Binning and Spectral Response

2.5nm Binning/Smile Correction

10nm

Wide Flatness

Sharp Response

data binning in spectral direction 4 pixels in VNIR 2 pixels in SWIR


Summary of Onboard Data Correction


19

Spectral Performance： Wavelength Shift/ Smile/ Keystone Before Launch Spectrometer Performance Misalignment of Assembly Onboard correction parameter Table

Launch/In Orbit Offset :Launch Vibration Condition Variable :Onboard Thermal Vacuum Condition

To measure

( install into Onboard Data Processor of HELU)

Spectral Performance

Correction Parameter Table: install into Ground Data Processing System



Wavelength shift of Flight Model (expected) VNIR <0.06nm SWIR <0.11 nm including launch and space environment conditions Onboard spectral calibrator monitors the wavelength shift.

VNIR SWIR Remarks Specification <10nm <12.5nm <1 pixel Normal Temp. & Pressure <1.0nm <2.5nm

After Onboard Correction

<10-5nm <10-5nm

After Launch Vibration Test Negligible Negligible Offset

Thermal Vacuum Test <0.058nm <0.106nm Variable

Total <0.06nm <0.11nm Expected

Value Onboard

Onboard Calibrator 0.2nm 0.625nm

Spectral Performance : Wavelength shift of evaluation model


Conclusions Onboard Data Correction of Hyperspectral Sensor of HISUI The validation tests of Onboard Data Correction function have been

completed using the data of functional evaluation model of Instrument. The smile performance after correction is very well. The method of Onboard Data Correction has been established. Status of HISUI Instrument Analyzing test results, FM is expected to achieve the spectral

performance better than specifications. The critical parts of FM, such as the telescope, the spectrographs and

the detectors, have been manufactured and the integration & tests of the sensor is proceeding .

▐ Acknowledgements HISUI project proceeds under the contract with METI (Ministry of Economy, Trade and

Industry).

3. Conclusions

Thank you very much for your attention !

Test Data of Evaluation Model（Spectral Calibration Accuracy at Normal Temp.）

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0 125 250 375 500 625 750 875 1000

Sp

ectr

al

Ca

lib

rati

on

Accu

racy

(n

m)

Pixel No. (CT derection)

Caribration Accuracy (Spectral) in VNIR Region

435nm546nm

-1.25

-1

-0.75

-0.5

-0.25

0

0.25

0.5

0.75

1

1.25

0 125 250 375 500 625 750 875 1000

Sp

ect

ral

Ca

lib

rati

on

Acc

ura

cy (

nm

)

Pixel No. (CT direction)

Caribration Accuracy (Spectral) in SWIR Region

1014nm1129nm1530nm

VNIR SWIR

3. Design of Flight Model


72.272.25

72.372.35

72.472.45

72.572.55

72.672.65

72.772.75

72.872.85

72.9

10 15 20 25 30 35 40

Wav

elen

gth p

ositi

on(P

ixel N

o) at

546

nm

Temp(C)

a) Temperature shift of Hg-Ar lamp line by VNIR spectrometer assembly

33C-> 13C-> 33C-> 20C

a

f

e

d

c

b

Onboard Temp. Range

24

VNIR :Wavelength Shift vs. Temp. (Thermal Vacuum Test)

＜0.23pixel =0.58nm

≦0.023pixel /2degC



22.322.35

22.422.45

22.522.55

22.622.65

22.722.75

22.822.85

22.922.95

23

10 15 20 25 30 35 40

Wav

elen

gth p

soiti

on(P

ixel N

o.) a

t 101

4nm

Temp(C)

b) Temperature shift of Hg-Ar lamp line by SWIR spectrometer assembly

33C->13C-> 33C->20C -> 22Ca

f

e

d

c

b

25

SWIR :Wavelength Shift vs. Temp. (Thermal Vacuum Test)

＜0.17pixel =1.08nm

Onboard Temp. Range

≦0.017pixel /2degC



スマイル補正（重みづけあり）※水色部分は0～1で重み付けを行い合成する。

中心波長位置

空間方向

波長方向

画素合成に使用する素子

2,096.249995 2,096.249996 2,096.249997 2,096.249998 2,096.249999 2,096.250000 2,096.250001 2,096.250002 2,096.250003 2,096.250004 2,096.250005

0 125 250 375 500 625 750 875 1000

Wav

elen

gth

（nm

）

Pixel No.



2096.23

2096.24

2096.25

2096.26

2096.27

2096.28

2096.29

2096.3

0 125 250 375 500 625 750 875 1000

Wav

elen

gth

（nm

）

Pixel No.



614.9614.91614.92614.93614.94614.95614.96614.97614.98614.99

615615.01615.02615.03615.04615.05615.06615.07615.08615.09

615.1

0 128 256 384 512 640 768 896 1024

Wav

elen

gth

（nm

）

Pixel No.



Spectral Performance After Onboard Correction

▐ Onboard correction Using the weighting function at

the binning


<0.06nm

<0.008nm

614.999995 614.999996 614.999997 614.999998 614.999999 615.000000 615.000001 615.000002 615.000003 615.000004 615.000005

0 128 256 384 512 640 768 896 1024

Wav

elen

gth

（nm

）

Pixel No.



<0.00001nm The test result is less than 0.000002nm

Optimize the weighting function

<0.00001nm The test result is less than 0.000003nm

Spectral

Spatial

Center Binning Pixels

２D-Array Detector

Filter Wheel Assembly - 4 Bandpass filters - NIST SRM2065 + Filter

Halogen lamps

Schematic Diagram Si -PD

Si -PD

InGaAs -PD

Telescope

3. Onboard calibratior of HISUI

Onboard Calibrator of Hyperspectral sensor

Onboard Calibrator of HISUI

▐ Onboard Calibrator of HISUI HISUI has Optical onboard calibrators .

3. Onboard calibrator of HISUI

Instrument Hyperspectral Sensor Multispectral Sensor

Light Source Two halogen lamps

Two halogen lamps

Detector to monitor

•Si-photodiode for VNIR •In-Ga-As-photodiode for SWIR

Si-photodiodes

Filters Band pass filters Spectral calibration filter

4 band pass filters The band pass wavelength of filter is matched to the spectral band for observation.

Spectral Calibration Accuracy (Target)

0.2nm (VNIR), 0.625nm (SWIR)

N/A

instrument development status and performances … · performances of hyperspectral imager suite...

Documents