• 제목/요약/키워드: Hadamard Transform Spectrometer

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

  • 박진배;곽대연;진승희;주진만
    • 대한전기학회논문지:전력기술부문A
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    • 제48권5호
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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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그릴 분광계를 사용하여 3중 부호화한 하다마드 변환 영상 분광계 (Triply-Encoded Hadamard Transform Imaging Spectrometer using the Grill Spectrometer)

  • 곽대연;박진배;박영재
    • 대한전기학회논문지:전력기술부문A
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    • 제48권12호
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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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비이상적 마스크로 인한 하다마드변환 스펙트럼 검파기 출력값의 신호대 잡음비 감소의 해결방안 (Compensation for the decrease of output SNR of hadamard transform spectrometer with nonideal mask)

  • 남지탁;박진배;윤태성
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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    • pp.4-7
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    • 1997
  • When we use Hadamard transform spectrometers (HTS), we can increase signal to noise ratio(SNR) by multiplexing which is done by masks. But if the mask has a single defective element, output-SNR decreases. In this paper the effect of a single defective element on the output-SNR is investigated. And a method of compensating for the defective mask element is presented.

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이차원 하다마드 트랜스폼 스펙트로미터에 관한 연구 (A Study on the 2-Dimensional Hadamard Transfrom Spectrometers)

  • 곽대연;강창식;박진배;윤태성
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 B
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    • pp.478-481
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    • 1997
  • Hadamard Transform Spectrometer (HTS) is an instrument which measures the spectrum of a source with high signal to noise ratio using multiplexing advantage. While the conventional HTS has the 1-dimensional characteristics because it measures only the spectrum, the system presented in this paper is 2-dimensional so that it can measure the spectrum of each position. We introduce here 2-dimensional Hadamard transform spectrometer and analyze it. The $T^{-1}$ method which recover the spectrum and compensate the transmissive nonideality of the stationary electro-optical mask(EOM) are applied to the system. By computer simulations we show we can get better estimates from the proposed system than that from the conventional HTS.

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

  • 박영재;서익수;박진배
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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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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하다마드 분광계측기의 마스크 설계 (A Design of Optimal Masks in Hadamard Transform Spectrometers)

  • 박진배
    • 대한의용생체공학회:의공학회지
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    • 제16권2호
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    • pp.239-248
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    • 1995
  • The method of increasing signal to noise ratio (SNR) in a Hadamard transform spectrometer (HTS) is multiplexing. The multiplexing is executed by a mask. Conventional masks are mechanical or electro-optical. A mechanical mask has disadvantages of jamming and misalignment. A stationary electro-optical mask has a disadvantage of information losses caused by spacers which partition mask elements. In this paper, a mixed-concept electro-optical mask (MCEOM) is developed by expanding the length of a spacer to that of lon-off mask element. An MCEOM is operated by stepping a movable mask. 2N measurements are required for N spectrum estimates. The average mean square error (AMSE) using MCEQM is equal to that using a stationary electro-optical mask without spacers for large N. The cost of manufacturing an MCEOM is lower than that of producing a conventional electro-optical mask because an MCEOM needs only (N + 1)/2 on-off mask elements whereas the con¬ventional electro-optical mask needs N on-off mask elements. There are no information losses in the spectrometers having an MCEOM.

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해더마드 트랜스폼 스펙트로미터의 성능 증진 방법과 평가 (Performance Enhancement and Evaluation in Hadamard Transform Spectrometers)

  • 박진배;김현규
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 A
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    • pp.277-280
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    • 1993
  • When the noise is mainly caused by a detector and is statistically independent of the incident radiation, the multiplexing inherent in the Hadamard transform (HT) spectrometer can provide an improved spectrum-estimate. A spectrum-estimate can be further improved when any nonidealities in the system are compensated. In this research, three spectrum-estimation methods for an HT spectrometer having a nonideal mask are discussed in terms of computational efficiency, statistical bias, the sources of error, and the mean-square error associated with a given estimate. In addition, the results obtained from computer simulations are used to verify the theoretical foundation of each method.

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