Published Papers - IJIMA Hiroshi

Maximum likelihood estimation of time-delay of ultrasonic signals based on Wigner distribution

H Ijima, A Ohsumi

Proc. SICE 2003 ANNUAL CONFERENCE ( IEEE )  pp.1774 -1778   2545 - 2549   2003  [Refereed]

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Recently, authors have proposed a method to estimate parameters of signals corrupted by random noise, using pseudo-Wigner distribution. In this paper efficacy of this method is demonstrated by experiments concerning to an ultrasonic radar system.

Recursive realization of the robust STFT

Djurovic, I, LA Stankovic, A Ohsumi, H Ijima

SEVENTH INTERNATIONAL SYMPOSIUM ON SIGNAL PROCESSING AND ITS APPLICATIONS, VOL 1, PROCEEDINGS ( IEEE )  vol.1, pp.157-160   157 - 160   2003  [Refereed]

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An efficient procedure is proposed for the realization of robust short-time Fourier transform (STFT) based on the recursive realization of the standard STFT. In the initial stage it uses the robust STFT calculated by iterative or sorting procedures and, after that, the recursive relation is applied. Basic difference from: the standard STFT realization is in limiting samples in the next instants, since they can be corrupted by an impulse noise. It results in a numerically efficient form of the STFT, keeping robustness to the impulse noise influence.

DOI

Instantaneous frequency estimation by using Wigner distribution and Viterbi algorithm

L Stankovic, Djurovic, I, A Ohsumi, H Ijima

2003 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOL VI, PROCEEDINGS ( IEEE )  vol.Ⅵ, pp.121-124   121 - 124   2003  [Refereed]

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Estimation of the instantaneous frequency (IF) in a high noise environment, by using the Wigner distribution (WD) and the Viterbi algorithm, is considered. The proposed algorithm combines the nonparametric IF estimation based on the WD maxima with minimization of the IF variations between consecutive points. Algorithm realization is performed recursively by using the (modified) Viterbi algorithm. Performances are compared with the IF estimation based on the WD maxima.

Estimation of line parameters using SLIDE algorithm and TF representations

Djurovic, I, S Stankovic, A Ohsumi, H Ijima

ICES 2002: 9TH IEEE INTERNATIONAL CONFERENCE ON ELECTRONICS, CIRCUITS AND SYSTEMS, VOLS I-111, CONFERENCE PROCEEDINGS ( IEEE )  vol.3, pp.1067-1070   1067 - 1070   2002  [Refereed]

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An effective procedure for estimation of line parameters using time-frequency (TF) representations and the SLIDE algorithm is presented. The line parameters are mapped into the instantaneous frequency (IF) of frequency modulated (FM) signals. The IF is estimated by using the TF representation. A new propagation approach is proposed. Performance of the proposed approach and the variable It-propagation are compared.

DOI

Maximum likelihood estimation for signal parameters using pseudo-Wigner distribution

H Ijima, A Ohsumi, H Sato, Djurovic, I

SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 ( IEEE )  pp.1598-1603   1464 - 1469   2002  [Refereed]

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In this paper a novel method for identifying unknown parameters associated with the received signals which are corrupted by random noise is established. Our key approach is to construct a likelihood (-ratio) function for the time-frequency random field generated by the pseudo-Wigner distribution. Numerical simulations are presented to verify the efficacy of the proposed method.

The enhanced detector of noisy signals using pseudo-Wigner distribution

IJIMA H.

Proc. IASTED Int. Conf. Signal Processing, Pattern Recognition and Applications, Rhodes, Greese, July, 2001   pp.95-100   95 - 100   2001  [Refereed]

On a Signal Detector using Wavelet-based Quadratic Time-Frequency Distribution

Proc. 5th WSES Multiconference on Circuits, Systems, Communications & Computers (CSCC 2001)   pp.42-47   2001  [Refereed]

High resolution detector for signals in random noise using wavelet-based Wigner distribution

A Ohsumi, H Ijima, T Sodeoka

2000 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, PROCEEDINGS, VOLS I-VI ( IEEE )  vol.I, pp.596-599   596 - 599   2000  [Refereed]

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A new signal detector of a chain of solitary signals corrupted by random noise is proposed by modifying the conventional Wigner distribution with wavelet. The efficacy of the proposed detector is shown by simulation studies.

Online detection of pulse sequence in random noise using a wavelet

A Ohsumi, H Ijima, T Kuroishi

IEEE TRANSACTIONS ON SIGNAL PROCESSING ( IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC )  47 ( 9 ) 2526 - 2531   1999.09  [Refereed]

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Two types of wavelet-based algorithms are proposed for an online detection of a train of unknown pulse signals corrupted by random noise. The mechanism of detecting singularities hidden in the noisy observation data is analyzed, and the performance of the proposed signal detectors is evaluated. Simulation studies are provided to confirm the effectiveness of the algorithms.

DOI

On-Line Detection of a Pulse Sequence in Random Noise Using a Wavelet

OHSUMI Akira, KUROISHI Tomoki, IJIMA Hiroshi

計測自動制御学会論文集 ( 計測自動制御学会 )  33 ( 7 ) 665 - 673   1997.07  [Refereed]

DOI

On-Line Detection of a Pulse Sequence in Random Noise Using a Wavelet

OHSUMI Akira, KUROISHI Tomoki, IJIMA Hiroshi

Transactions of the Society of Instrument and Control Engineers ( The Society of Instrument and Control Engineers )  33 ( 7 ) 665 - 673   1997  [Refereed]

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The wavelet-based algorithms are proposed for an on-line detection of a train of pulse signals corrupted by random noise. The key approach is to catch the time instant at which the pulse signal changes by computing the correlation between wavelet and observation data. The effectiveness of the proposed algorithms are confirmed by numerical simulation experiments.

DOI

Performance Analysis of the On-line Signal Detectors Using a Wavelet

OHSUMI Akira, IJIMA Hiroshi

インテリジェント・システム・シンポジウム講演論文集 = FAN Symposium : fuzzy, artificial intelligence, neural networks and computational intelligence   6   400 - 403   1996.10  [Refereed]

Wavelet-Based On-line Detectors for Pulse Signals in Random Noise and Their Performance Analysis

Proc. World Automation Congress (WAC’98)   pp.265-272   1985  [Refereed]