Thumwarin, Pitak

Preferred name

Thumwarin, Pitak

Alternative Name

Thumwarin, P.

Main Affiliation

Music Science and Engineering

pitak.th@kmitl.ac.th

Now showing 1 - 10 of 14

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On-line Thai numeral recognition
(2000-12-01)
Matsuura, Takenobu
;
Tangtisanon, Prasan
;
Thumwarin, Pitak
This paper discusses on-line Thai numeral recognition based on characteristics of pen-point movement in handwriting process. The characteristics are described by expanding the time sequences of pen-point movement in handwriting process into Fourier series, respectively. It assumes here that the coefficients in the Fourier series are considered as the input and output sequences of a system, respectively. The feature of Thai numeral are selected using K-L expansion of the impulse response of the system.
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Tri-band rectangular spiral slot antenna with L-shaped slot antenna for WLAN and radar applications
(2006-12-01)
Wiriyacosol, Pavita
;
Anantrasirichai, Noppin
;
Thumwarin, Pitak
;
Wakabayashi, Toshio
Tri-band rectangular spiral slot (RSS) antenna with an L-shaped slot antenna insertion is introduced in this paper. The antenna was designed on the substrate with 2.2 of dielectric constant and 1.575 mm of thickness. FDTD method was adopted to evaluate the proposed antenna characteristics A rectangular spiral slot antenna was designed to support dual-frequency at 2.44 GHz and 8 GHZ. An L-shaped slot antenna was inserted to obtain more resonant frequency at 5.2 GHz. The simulation results revealed that the proposed antenna could be used to support tri-band of frequency which is compatible to IEEE 802.11a or HIPERLAN (5.2 GHz) standard, IEEE 802.11b/g (Wi-Fi 2.44 GHz) standard and 8.0 GHz satellite or radar communications. © 2006 ICASE.
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On-line writer dependent character recognition for khmer based on FIR system characterizing handwriting motion
(2008-10-06)
Thumwarin, P.
;
Khem, S.
;
Janchitraponvej, K.
;
Matsuura, T.
We proposed an on-line writer dependent Khmer recognition method based on FIR system characterizing handwriting motion. The handwriting motion can be described by two features, barycenter trajectory and its velocity. The barycenter is determined from the center point of the script and the two adjacent pen-point positions with respect to time in handwriting process. Then the barycenter and its velocity are expanded into wavelet series to extract the time-frequency characteristics of handwriting motion. In this paper, the FIR(finite impulse response) system characterizing the handwriting motion is introduced. In this case, the wavelet coefficients of the velocity and trajectory of the barycenter are used as the input and output of the FIR system, respectively. The obtained impulse response of the FIR system is considered as the individual feature for a particular character. Finally, Khmer alphabets can be recognized by using the Euclidean distance between the impulse responses obtained from the reference alphabets and those of the alphabets to be recognized. Khmer character recognition experiments were performed on a database consisting of 4770 of numerals and alphabets written by 15 people. As the results, the average of the recognition rate was 97.05%. ©2008 IEEE.
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An automatic system for firearm identification
(2008-12-01)
Thumwarin, Pitak
This research proposes an automatic system for firearm identification. In the proposed method, firearm can be identified by using the head of cartridge case image. The unique feature of the individual gun can be extracted by using the absolute value of Fourier coefficients of polar image of cartridge case on circles with different radii. The obtained absolute value of Fourier coefficients is considered as the rotation invariance feature of the cartridge case image. Finally, the Fisher's linear discriminant function is used to identify the gun. The result successfully revel the effectiveness of the method of implementation for some extent. © 2008 IEEE.
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On-line writer recognition for Thai numeral
(2002-01-01)
Thumwarin, P.
;
Tangtisanon, P.
;
Murata, S.
;
Matsuura, T.
This paper discusses an on-line writer recognition for Thai numerals. First, a center point of a Thai numeral is determined after normalization. Then the center point is shifted to an origin. Secondly, the distance from the origin to the pen-point position in the handwriting process is measured and the area of a triangle determined from the origin and the two adjacent points of the pen-point position is calculated. Thirdly, the features of pen-point movement in the process are extracted by expanding the time sequence of the above distance and area into Fourier series. Then the features of pen-point movement are represented in terms of Fourier coefficients. Fourthly, in order to describe the handwriting process features, the FIR system with the above coefficients as input and output of the system is introduced. Then the impulse response of the FIR system is used as the feature of handwriting process. Furthermore in order to recognize the writer, K-L expansion (J.T. Tou and R.C. Gonzalez "Pattern Recognition Principles", Addison-Wesley, pp. 269, 1974) of the obtained impulse response is used. In the experiments, the average rates of type I (false rejection) and type II (false acceptance) error were 17.14% and 9.26%, respectively.
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FIR firearm identification system
(2009-01-01)
Thumwarin, P.
;
Prasit, C.
;
Suwanvesh, T.
;
Matsuura, T.
We propose a FIR(Finite impulse response) firearm identification system. The firearm can be identified by using the impulse response of the FIR system characterizing the rotation invariant feature of the cartridge case image. In this case, the rotation invariant feature can be extracted by the magnitude of Fourier coefficients of polar image of the cartridge. Then the obtained Fourier coefficients are used as the input and the output of the FIR system. The impulse response of the FIR system is used as the unique feature for firearm identification. Finally, the firearm can be identified by the Fisher's linear discriminant function. The experimental results are taken to show the effectiveness of the proposed method.
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On-line writer dependent character recognition for Khmer based on FIR system characterizing handwriting motion
(2008-12-01)
Thumwarin, Pitak
;
Khem, Sochenda
;
Janchitraponvej, Kanok
;
Matsuura, Takenobu
We propose an on-line writer dependent Khmer recognition method based on time-frequency characteristics of handwriting motion. The handwriting motion can be described by two features, barycenter trajectory and its velocity of pen-tip movement. Then the barycenter trajectory and its velocity of the pen-tip movement are expanded into wavelet series to extract the time-frequency characteristics of the handwriting motion. After that, The fluctuation of the wavelet coefficients can be reduced by the FIR(Finite Impulse Response) Wiener filter. Moreover, the FIR system characterizing the time-frequency characteristics of the handwriting motion is introduced by using wavelet coefficients of the velocity and trajectory of the barycenter with fluctuation reduced as the input and output of the FIR system, respectively. The obtained impulse response of the FIR system is considered as the individual feature for a particular character. Finally, Khmer alphabets can be recognized by using the Euclidean distance between the impulse responses obtained from the reference alphabets and those of the alphabets to be recognized. Khmer character recognition experiments were performed on a database consisting of 6,750 of numerals and alphabets written by 17 people. As the results, the average of the recognition rate was 98.17%. © 2008 SICE.
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Firearm identification based on FIR system characterizing rotation invariant feature of cartridge case image
(2008-12-01)
Thumwarin, P.
;
Prasit, C.
;
Boonbumroong, P.
;
Matsuura, T.
We propose firearm identification method based on FIR system characterizing rotation invariant feature of cartridge case image. The rotation invariant feature is represented by the absolute value of Fourier coefficients of polar image on circles with different radii of the cartridge case's primer. Then the FIR(Finite impulse response) system characterizing the rotation invariant feature of cartridge case's primer image is introduced. The absolute value of Fourier coefficients obtained from the polar image on the circles with different radii are used as the input and output of the FIR system, respectively. The obtained impulse response of the FIR system is considered as the unique feature of the individual gun. Finally, a firearm can be identified by using the Fisher's linear discriminant function of the obtained impulse response of the FIR system. The firearm identification experiments are conducted to show the effectiveness of the proposed method. © 2008 IEEE.
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Firearm identification based on rotation invariant feature of cartridge case
(2008-12-01)
Thumwarin, P.
;
Prasit, C.
;
Matsuura, T.
This paper, proposes firearm identification method based on rotation invariant feature of cartridge case image. The rotation invariance feature is represented by the absolute value of Fourier coefficients of polar image of cartridge case on circles with different radii. The absolute value of Fourier coefficients is considered as the individual feature of the particular gun. Finally, the firearm can be identified by the distance between the absolute value of Fourier coefficients obtained from the reference cartridge case and the cartridge case to be identified. The firearm identification experiments are given to show the effectiveness of the proposed method. © 2008 SICE.
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On-line writer identification system characterizing velocity and areal velocity in handwriting process
(2009-12-01)
Matsuura, Takenobu
;
Thumwarin, Pitak
In this paper,we propose an on-line writer identification system characterizing velocity and areal velocity of pen-tip movement in handwriting process. The writer identification system consists of two finite impulse response (FIR) systems characterizing the velocity and areal velocity in handwriting process. Individual handwriting feature is represented by the impulse response of the FIR system. Writer can be identified by evaluating the difference between the impulse responses of the FIR systems for the reference and a person to be identified. In our experiments 2,000 Thai numerals were used to identify 10 different writers.

Thumwarin, Pitak

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