• 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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    • 2005.10a
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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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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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Design of MRI Spectrometer Using 1 Giga-FLOPS DSP (1-GFLOPS DSP를 이용한 자기공명영상 스펙트로미터 설계)

  • 김휴정;고광혁;이상철;정민영;장경섭;이동훈;이흥규;안창범
    • Investigative Magnetic Resonance Imaging
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    • v.7 no.1
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    • pp.12-21
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    • 2003
  • Purpose : In order to overcome limitations in the existing conventional spectrometer, a new spectrometer with advanced functionalities is designed and implemented. Materials and Methods : We designed a spectrometer using the TMS320C6701 DSP capable of 1 giga floating point operations per second (GFLOPS). The spectrometer can generate continuously varying complicate gradient waveforms by real-time calculation, and select image plane interactively. The designed spectrometer is composed of two parts: one is DSP-based digital control part, and the other is analog part generating gradient and RF waveforms, and performing demodulation of the received RF signal. Each recover board can measure 4 channel FID signals simultaneously for parallel imaging, and provides fast reconstruction using the high speed DSP. Results : The developed spectrometer was installed on a 1.5 Tesla whole body MRI system, and performance was tested by various methods. The accurate phase control required in digital modulation and demodulation was tested, and multi-channel acquisition was examined with phase-array coil imaging. Superior image quality is obtained by the developed spectrometer compared to existing commercial spectrometer especially in the fast spin echo images. Conclusion : Interactive control of the selection planes and real-time generation of gradient waveforms are important functions required for advanced imaging such as spiral scan cardiac imaging. Multi-channel acquisition is also highly demanding for parallel imaging. In this paper a spectrometer having such functionalities is designed and developed using the TMS320C6701 DSP having 1 GFLOPS computational power. Accurate phase control was achieved by the digital modulation and demodulation techniques. Superior image qualities are obtained by the developed spectrometer for various imaging techniques including FSE, GE, and angiography compared to those obtained by the existing commercial spectrometer.

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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.

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).

Real-time Interactive Control of Magnetic Resonance Imaging System Using High-speed Digital Signal Processors (고속 DSP를 이용한 실시간 자기공명영상시스템 제어)

  • 안창범;김휴정;이흥규
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.40 no.5
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    • pp.341-349
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    • 2003
  • A real time interactive controller (spectrometer) for magnetic resonance imaging (MRI) system has been developed using high speed digital signal processors (DSP). The controller generates radio frequency (rf) waveforms and audio frequency gradient waveforms and controls multiple receivers for data acquisition. By employing DSPs having high computational power (e.g., TMS320C670l) real time generation of complicated gradient waveforms and interactive control of selection planes are possible, which are important features in real-time imaging of moving organs, e.g., cardiac imaging. The spectrometer was successfully implemented at a 1.5 Tesla whole body MRI system for clinical application. Performance of the spectrometer is verified by various experiments including high- speed imaging such as fast spin echo (FSE) and echo planar imaging (EPI). These high-speed imaging techniques reduce measurement time, however, usually intensify artifact if there is any systematic phase error or jitter in the synchronization between the transmitter, receiver, and gradients.

Single-Kernel Corn Analysis by Hyperspectral Imaging

  • Cogdill, R.P.;Hurburgh Jr., C.R.;Jensen, T.C.;Jones, R.W.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1521-1521
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    • 2001
  • The objective of the research being presented was to construct and calibrate a spectrometer for the analysis of single kernels of corn. In light of the difficulties associated with capturing the spatial variability in composition of corn kernels by single-beam spectrometry, a hyperspectral imaging spectrometer was constructed with the intention that it would be used to analyze single kernels of corn for the prediction of moisture and oil content. The spectrometer operated in the range of 750- 1090 nanometers. After evaluating four methods of standardizing the output from the spectrometer, calibrations were made to predict whole-kernel moisture and oil content from the hyperspectral image data. A genetic algorithm was employed to reduce the number of wavelengths imaged and to optimize the calibrations. The final standard errors of prediction during cross-validation (SEPCV) were 1.22% and 1.25% for moisture and oil content, respectively. It was determined, by analysis of variance, that the accuracy and precision of single-kernel corn analysis by hyperspectral imaging is superior to the single kernel reference chemistry method (as tested).

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A High-Lateral Resolution MALDI Microprobe Imaging Mass Spectrometer Utilizing an Aspherical Singlet Lens

  • Han, Sang Yun;Kim, Hwan Jin;Ha, Tae Kyung
    • Bulletin of the Korean Chemical Society
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    • v.34 no.1
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    • pp.207-210
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    • 2013
  • We report the construction of a MALDI imaging mass spectrometer equipped with a specially designed laser focusing lens, a compact aspherical singlet lens, that obtains a high-lateral imaging resolution in the microprobe mode. The lens is specially designed to focus the ionization laser (${\lambda}$ = 355 nm) down to a $1{\mu}m$ diameter with a long working distance of 34.5 mm. With the lens being perpendicular to the sample surface and sharing the optical axis with the ion path, the imaging mass spectrometer achieved an imaging resolution of as good as $5{\mu}m$ along with a high detection sensitivity of 100 fmol for peptides. The mass resolution was about 900 (m/${\Delta}m$) in the linear TOF mode. The high-resolution capability of this instrument will provide a new research opportunity for label-free imaging studies of various samples including tissues and biochips, even for the study at a single cell level in the future.

Optical System Design and Image Processing for Hyperspectral Imaging Systems (초분광 분해기의 광학계 설계 및 영상 처리)

  • Heo, A-Young;Choi, Seung-Won;Lee, Jae-Hoon;Kim, Tae-Hyeong;Park, Dong-Jo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.2
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    • pp.328-335
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    • 2010
  • A hyperspectral imaging spectrometer has shown significant advantages in performance over other existing ones for remote sensing applications. It can collect hundreds of narrow, adjacent spectral bands for each image, which provides a wealth of information on unique spectral characteristics of objects. We have developed a compact hyperspectral imaging system that successively shows high spatial and spectral resolutions and fast data processing performance. In this paper, we present an overview of the hyperspectral imaging system including the strucure of geometrical optics and several image processing schemes such as wavelength calibration and noise reduction for image data on Visible and Near-Infrared(VNIR) and Shortwave-Infrared(SWIR) band.