• Title/Summary/Keyword: Imaging spectrometer

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HYPERSPECTRAL IMAGING SPECTROMETER WITH A NOVEL ZOOMING FUNCTION

  • Choi Jin;Kim Tae Hyung;Kong Hong Jin;Lee Jong-Ung
    • Proceedings of the KSRS Conference
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    • pp.213-216
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    • 2005
  • A novel hyperspectral imaging spectrometer controlling spatial and spectral resolution individually has been proposed. This imaging spectrometer uses a zoom lens as a telescope and a focusing element. It can change the spatial resolution fixing the spectral resolution or the spectral resolution fixing the spatial resolution. Here, we report the concept of the hyperspectral imaging spectrometer with the novel zooming function and the optical design of a zoom lens as the focusing element. By using lens module and third-order aberration theory, we have presented the initial design of four-group zoom lens with external entrance pupil. And the optimized zoom lens with a focal length of 50 to 150 mm is obtained from the initial design by the optical design software. As a result, the designed zoom lens shows satisfactory performances in wavelength range of 450 to 900 nm as a focusing element in an imaging spectrometer. Furthermore, the collimator lens of the imaging spectrometer is designed through the third-order aberration correction by using an iterative process.

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Triply-Encoded Hadamard Transform Imaging Spectrometer using the Grill Spectrometer (그릴 분광계를 사용하여 3중 부호화한 하다마드 변환 영상 분광계)

  • Kwak, Dae-Yun;Park, Jin-Bae;Park, Yeong-Jae
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.12
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    • pp.1527-1536
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    • 1999
  • In this paper, a triply-encoded Hadamard transform imaging spectrometer is proposed by applying the grill spectrometer to the Hadamard transform imaging spectrometer. The proposed system encodes the input radiation triply ; once through the input image mask and twice through the two masks in the grill spectrometer. We use an electro-optical mask in the grill spectrometer which is controlled by a left-cyclic simplex matrix. Then we modeled the system using $D^{-1}$ method. In this paper, the average mean square error associated with a recovered estimate is considered for performance evaluation. The relative performance is compared with those of the other conventional systems.

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Optomechanical Design of a Compact Imaging Spectrometer for a Microsatellite STSAT3

  • Lee, Jun-Ho;Lee, Chi-Weon;Kim, Yong-Min;Kim, Jae-Wook
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.193-200
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    • 2009
  • A compact imaging spectrometer (COMIS) is currently under development for use in the STSAT3 microsatellite. COMIS images the Earth's surface and atmosphere with ground sampling distances of ${\sim}30m$ in the $18{\sim}62$ spectral bands ($4.0{\sim}1.05{\mu}m$) for the nadir looking at an altitude of 700 km. COMIS has an imaging telescope and an imaging spectrometer box into which three electronics PCBs are embedded. These are designed into a single assembly with dimensions of 35(L) $\times$ 20(W) $\times$ 12(H) $cm^3$ and a mass of 4.3 kg. Optomechanical design efforts are focused on manufacturing ease, alignment, assembly, testing and improved robustness in space environments. Finite element analysis demonstrates that COMIS will survive in launch and space environments and perform the system modulation transfer function (MTF) in excess of 0.29 at the Nyquist frequency of the CCD detector (38.5 lines-per-mm).

Development and Verification of the Compact Airborne Imaging Spectrometer System

  • Lee, Kwang-Jae;Yong, Sang-Soon;Kim, Yong-Seung
    • Korean Journal of Remote Sensing
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    • v.24 no.5
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    • pp.397-408
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    • 2008
  • A wide variety of applications of imaging spectrometer have been proved using data from airborne systems. The Compact Airborne Imaging Spectrometer System (CAISS) was jointly designed and developed as the airborne hyperspectral imaging system by Korea Aerospace Research Institute (KARI) and ELOP inc., Israel. The primary mission of the CAISS is to acquire and provide full contiguous spectral information with high spatial resolution for advanced applications in the field of remote sensing. The CAISS consists of six physical units; the camera system, the gyro-stabilized mount, the jig, the GPS/INS, the power inverter and distributor, and the operating system. These subsystems are to be tested and verified in the laboratory before the flight. Especially the camera system of the CAISS has to be calibrated and validated with the calibration equipments such as the integrating sphere and spectral lamps. To improve data quality and its availability, it is the most important to understand the mechanism of imaging spectrometer system and the radiometric and spectral characteristics. The several performance tests of the CAISS were conducted in the camera system level. This paper presents the major characteristics of the CAISS, and summarizes the results of performance tests in the camera system level.

A Study on Hadamard Transform Imaging Spectromers (하다마드 트랜스폼 이민징 스펙트로미터에 관한 연구)

  • Park, Jin-Bae;Kwak, Dae-Yeon;Jin, Seung-Hee;Joo, Jin-Man
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.5
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    • pp.571-579
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    • 1999
  • In this paper, a Hadamard transform imaging spectrometer(HTIS) is proposed by using a grill spectrometer. And we reconfigure the system by using the grill sectrometer which uses a left cyclic S-matrix instead of the conventional right cyclic one. Then, we model the Hadamard transform imaging spectrometer and apply the mask characteristics compensation method, i.e. $ {T}^{-1}$ method, to complete fast algorithm. Also, through computer simulations the superiority of the proposed system in this paper to the conventional Hadamard transform spectrometer(HTS) is proved and the performance of the two systems are compared by introducing average mean square error(AMSE) as the algebraic criterion.

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Stray Light Analysis of a Compact Imaging Spectrometer for a Microsatellite STSAT-3 (과학기술위성3호 부탑재체 소형영상분광기 미광 해석)

  • Lee, Jin Ah;Lee, Jun Ho
    • Korean Journal of Optics and Photonics
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    • v.23 no.4
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    • pp.167-171
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    • 2012
  • This paper reports on the stray light analysis results of a compact imaging spectrometer (COMIS) for a microsatellite STSAT-3. COMIS images Earth's surface and atmosphere with ground sampling distances of 27 m at the 18~62 spectral bands (0.4 ~ 1.05 ${\mu}m$) for the nadir looking at an altitude of 700 km. COMIS has an imaging telescope and an imaging spectrometer box into which three electronics PCBs are embedded. The telescope images a $27m{\times}28km$ area of Earth surface onto a slit of dimensions $11.8{\mu}m{\times}12.1mm$. This corresponds to a ground sampling distance of 27 m and a swath width of 28 km for nadir looking posture at an altitude of 700 km. Then the optics relays and disperses the slit image onto the detector thereby producing a monochrome image of the entrance slit formed on each row of detector elements. The spectrum of each point in the row is imaged along a detector column. The optical mounts and housing structures are designed in order to prevent stray light from arriving onto the image and so deteriorating the signal to noise ratio (SNR). The stray light analysis, performed by a non-sequential ray tracing software (LightTools) with three dimensional housing and lens modeling, confirms that the ghost and stray light arriving at the detector plane has the relative intensity of ${\sim}10^{-5}$ and furthermore it locates outside the concerned image size i.e. the field of view of the optics.

Triply Encoded Hadamard Transform Imaging Spectrometer: Spectrum Recovery Method (3번 부호화한 하다마드 변환 영상 분광계의 스펙트럼 복원법)

  • Park, Yeong-Jae;Seo, Ik-Su;Park, Jin-Bae
    • Proceedings of the KIEE Conference
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    • pp.597-599
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    • 1999
  • Triply encoded HTIS(hadamard transform imaging spectrometer) is a system which applies the grill spectrometer to the HTIS. we consider a nonideality of mask transparent characteristic in estimating spectrum. Triply encoded system increases the SNR(signal to noise ration) by multiplexing effect. In this paper, we suggest an advanced $T^{-1}$ method for spectrum recovery. Then, we proved the superiority of the suggested method by comparing the average MSE(mean square error) of the other recovery methods.

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DESIGN AND DEVELOPMENT OF THE COMPACT AIRBORNE IMAGING SPECTROMETER SYSTEM

  • Lee, Kwang-Jae;Yong, Sang-Soon;Kim, Yong-Seung
    • Proceedings of the KSRS Conference
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    • pp.118-121
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    • 2007
  • In recent years, the hyperspectral instruments with high spatial and high spectral resolution have become an important component of wide variety of earth science applications. The primary mission of the proposed Compact Airborne Imaging Spectrometer System (CAISS) in this study is to acquire and provide full contiguous spectral information with high quality spectral and spatial resolution for advanced applications in the field of remote sensing. The CAISS will also be used as the vicarious calibration equipment for the cross-calibration of satellite image data. The CAISS consists of six physical units: the camera system, the Jig, the GPS/INS, the gyro-stabilized mount, the operating system, and the power inverter and distributor. Additionally, the calibration instruments such as the integrated sphere and spectral lamps are also prepared for the radiometric and spectral calibration of the CAISS. The CAISS will provide high quality calibrated image data that can support evaluation of satellite application products. This paper summarizes the design, development and major characteristic of the CAISS.

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