Noboru Yabuki

Versatile current-mode biquadratic circuit using only plus type CCCIIs and grounded capacitors

This paper introduces a versatile current-mode biquadratic circuit using second generation current-controlled current conveyors (CCCIIs). The circuit is constructed with two plus type multiple current output CCCIIs (MO-CCCIIs) and two grounded capacitors. The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by choosing appropriate input and output terminals without any component matching conditions. Additionally, the circuit parameters Q and ω0 can be set orthogonally by adjusting the bias currents of the MO-CCCIIs and grounded capacitors. The biquadratic circuit enjoys very low sensitivities to the circuit components. Some examples are given together with simulated results by PSPICE.

Novel current-mode biquadratic circuit using only plus type DO-DVCCs and grounded passive components

This paper introduces a novel current-mode biquadratic circuit using plus type differential voltage current conveyors (DVCCs) and grounded passive components. The circuit is constructed with two plus type dual current output DVCCs (DO-DVCCs), two grounded capacitors and two resistors. The circuit can realize multiple circuit transfer functions by choosing the appropriate input and output terminals. Additionally, the circuit parameters Q and ω 0 can be set orthogonally by adjusting the passive components. The biquadratic circuit enjoys very low sensitivities to the circuit components. An example is given together with simulated results by PSPICE.

Electronically tunable first-order all-pass circuit employing DVCC and OTA

This article presents a realisation of an electronically tunable first-order all-pass circuit employing a differential voltage current conveyor (DVCC), an operational trans-conductance amplifier (OTA) and two MOS conductance. The circuit can realise two all-pass characteristics by choosing the current output of the OTA. Additionally, the circuit parameters ω0 and H can be set independently by tuning the circuit active components electronically. Sensitivity analysis shows that the circuit enjoys very low sensitivity to the circuit components. An example is given together with simulated results by PSPICE.

Region detection using color similarity

In this paper, we propose a method to detect a road sign from a road scene image in the daytime. In order to utilize the color feature of the sign efficiently, the color distribution of sign is examined, and then a color similarity map is constructed. Assuming that the color distribution is a normal distribution, a color similarity map is obtained. Additionally, the color similarity shown on the map is incorporated into an image function of an active net model. A road sign is extracted as if it is wrapped up in an active net. Some experimental results obtained by applying an active net to images are presented.

New s-z transformation and its switched capacitor realization

A novel s-z transformation called the mixed-discrete integrator, (MDI), which results in less frequency warping than the conventional transformations, is proposed. It is derived by combining the bilinear and lossless-discrete-integrator transformations with ratio k(0<or=k<or=1). The realization of switched-capacitor filters using this transformation is discussed for a leapfrog structure.<<ETX>>

A Study on Contour Line and Internal Area Extraction Method by using the Self-Organization Map

Recently, intelligent transport system (ITS) is actively developed. There are big development areas in it. Within those areas, the research on detection and recognition of the road sign is one of the most important development areas. In this paper, we show the process improvement in order to extract the contour line and recognize the road sign shape from it. We have proposed the new extraction method of the contour line and internal areas from the road sign instantaneously by using the self organization map (SOM)

Novel current-mode biquadratic circuit using only plus type DO-DVCCCs

This paper introduces a novel current-mode biquadratic circuit using only plus type differential voltage current-controlled current conveyors (DVCCCs) and grounded capacitors. The biquadratic circuit is constructed with two plus type dual current output DVCCCs (DO-DVCCCs) and two grounded capacitors. The circuit can realize biquadratic circuit transfer functions by choosing the appropriate input and output terminals. Additionally, the circuit parameters Q and ω0 can be set orthogonally by adjusting the bias currents and capacitors. The biquadratic circuit enjoys very low sensitivity to the circuit components. An example is given together with simulated results by PSPICE.

Proposal for a convergence criterion to the active net in two steps

In this paper, we propose a method for detecting a road sign from a scene image in the daytime. This method uses an active net in two steps. The active net is a deformable lattice network model which minimizes an energy function to detect the region of a target. In the proposed method, the first active net roughly estimates a position of a target. For the better target detection, we put the second active net around the estimated position. Its experimental results show the effectiveness and efficiency of the proposed algorithm. However, the active net can not occasionally detect the target region. This case shows that the progress of energy cannot converge smoothly. So we have developed the convergence criterion whether a good detection or an unsuccessful detection. That is, by evaluating features of the progress of the energy, the computation of the active net is automatically and fast stopped.

Electronically tunable inverse active filters employing OTAs and grounded capacitors

This paper introduces inverse active filters employing operational transconductance amplifiers (OTAs) and grounded capacitors. The filter circuits can realise inverse low-pass, inverse band-pass and inverse high-pass transfer functions by addition of the circuit currents. Additionally, the circuit parameters ω0, Q and H can be set orthogonally or independently by adjusting the bias currents of the OTAs. The inverse filter circuits enjoy very low sensitivities to active and passive components. The achievement examples are given together with simulation results by PSPICE.

A control system for electrical appliances using eye-gaze input

In this paper we propose an eye-gaze system that uses freely arranged multiple network cameras to reduce the burden of users. The proposed eye-gaze system is a remote control system that allows the users to control appliances by gazing at the electrical appliances. The proposed system is composed of a block of Face Detector, Camera Controller, Eye-gaze Detector and Remote Controller. We propose a method for the face detector using multiple cameras, so that the head of the user does not have to be stationary while it is under the eye-gaze detector process.