Trirat, Akraphon

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Trirat, Akraphon
Alternative Name
Trirat, A.
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Email
akraphon.tr@kmitl.ac.th

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    Tunable bandpass/bandstop digital filters basedon 1st-order allpass network instead of unit delay
    (2019-07-01)
    Sutthikarn, Pemmavit
    ;
    Chivapreecha, Sorawat
    ;
    Jongsataporn, Thitaphan
    ;
    Trirat, Akraphon
    This paper presents a design and realization of tunable bandpass and bandstop digital filters based on using tunable digital lowpass and highpass filters. The frequency response of both digital lowpass and highpass filters which called prototype filters can be changed/tuned by replacing unit delay elements in filter structure with 1<sup>st</sup>-order allpass network. From the tunable digital lowpass and highpass filters, the cascade connection of them can give tunable bandpass filter, the parallel connection can give tunable bandstop filter. The conditions of using proposed tunable bandpass/bandstop filters will be analyzed and explained in this work. A high flexibility of tuning both center frequency and bandwidth can be achieved from the proposed design and realization. Simulation results also be compared with experimental results from hardware implementation on FPGA using NI-myRIO device to ensure that the obtained frequency responses are correspondence.
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    Automated classification of malaria parasite species on thick blood film using support vector machine
    (2016-02-04)
    Pinkaew, Aeggarut
    ;
    Limpiti, Tulaya
    ;
    Trirat, Akraphon
    Malaria is a serious global health problem. It requires fast and effective diagnosis for detecting and classifying the type of infection. Proper treatment should be administered in a timely fashion to prevent an outbreak. Microscopic examination of thick blood films is one of the current standards for malaria diagnosis. However, inspecting a thick blood film is time-consuming and requires experienced technicians. Hence, for developing countries where most cases of malaria occur but microscopy expertise may not be available, a computerized system to aid such diagnosis is desirable. In this paper, an automated classification system operating on digitized images of thick blood film has been developed to classify between Plasmodium falciparum and Plasmodium vivax malaria parasite species. The system is fully automated. It is fast and can be handled by non-experts. We calculate five statistical features - mean, standard deviation, kurtosis, skewness and entropy - from four color channels (green, intensity, saturation, and value) of these images. The features are then projected onto a subspace representing image characteristics from both species. The projected features are used by the support vector machine for classification. It is found that the algorithm has acceptable training error and can classify test images with good accuracy.
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    A tunable multiple outputs FIR filter structure realization
    (2019-01-01)
    Sutthikarn, Pemmavit
    ;
    Chivapreecha, Sorawat
    ;
    Trirat, Akraphon
    This paper proposes a design of a new finite impulse response (FIR) digital filter structure which gives 6-tunable frequency responses as 2 low-pass filters (LPF), 2 high-pass filters (HPF), 1 band-pass filter (BPF) and 1 band-stop filter (BSF) at the same time. The design procedure is initiated from 2 LPFs design. However in order to obtain a tunable filter, the unit delay is replaced by first-order single-multiplier structure for all-pass filter. Therefore, this new structure can be achieved and called tunable multiple outputs FIR filter. Finally, the amplitude responses that obtained from proposed structure can show the tunable capability using tuning parameter.