Scanning electron microscope (SEM) observation of an insulator material often suffers an abnormal contrast image from a charging phenomenon, which is caused by accumulation of a part of primary electrons inside the material. In order to avoid the charging phenomenon, it is important to observe the insulator material under the primary electron energy condition that the total electron emission yield σ is equal to unity. In order to find out the above primary electron energy condition, we have measured the electron emission yield σ as a function of the primary electron energy Ep for several insulator materials. In this case the specimen (= the insulator material) has been heated up to 700 °C where the charging phenomenon disappears. The value of σ has been determined by measuring both the primary electron current (Ip) and the conduction electron current (Ia=Ip-σIp) flowing to the ground through the specimen stage. We also found that the primary electron energy corresponding to σ=1 can easily be determined by the condition that the conduction electron current Ia takes a minimum value. For example, the primary electron energy that gives the condition of σ=1 for Si3N4 has been found to be Ep=3.1 keV. We have also measured the secondary electron emission yield δ of the insulator material using the contrast method, which is based on the signal intensity ratio of the SEM image of the boundary between Au and the insulator material.
Vanadyl-phthalocyanine (VOPc) thin film deposited on a KBr substrate by the molecular beam epitaxy (MBE) method consists of nano-VOPc crystals grown with epitaxy. The nano-VOPc crystal becomes a commensurate square shape by the annealing treatment at 150°C. Moreover, the size of the nano-crystal is controllable by changing the conditions of the MBE deposition and the thermal treatment. The growth processes of nano-crystals on KBr substrate are clarified experimentally and they are closely related to a strong interaction between VOPc molecule and KBr substrate. Their mechanisms can be explained in terms of the surface diffusion of the VOPc moleculs on KBr substrate.
X-ray diagnosis depends on the intensity of transmitted and scattered waves in X-ray propagation in biomedical media. X-ray is scattered and absorbed by tissues, such as fat, bone and internal organs. However, image processing for medical diagnosis, based on the scattering and absorption characteristics of these tissues in X-ray spectrum is not so much studied. To obtain precise information of tissues in a living body, the accurate characteristics of scattering and absorption are required. In this paper, X-ray scattering and absorption in biomedical media are studied using 2-dimensional FDTD method. As a result of computer simulation, the intensities of transmitted and scattered waves are presented numerically. The scattering intensity is compared with the result of 3-dimensional statistical electromagnetic theory. In FDTD method, the size of analysis space is very limited by the performance of available computers. The way of computation to overcome this limitation is also shown. The theoretical result shows relatively good approximation by considering proper parameters.
It is necessary to monitor the daily health condition for preventing stress syndrome. In this study, it was proposed the method assessing the mental and physiological condition, such as the work stress or the relaxation, using heart rate variability at real time and continuously. The instantanuous heart rate (HR), and the ratio of the number of extreme points (NEP) and the number of heart beats were calculated for assessing mental and physiological condition. In this method, 20 beats heart rate were used to calculate these indexes. These were calculated in one beat interval. Three conditions, which are sitting rest, performing mental arithmetic and watching relaxation movie, were assessed using our proposed algorithm. The assessment accuracies were 71.9% and 55.8%, when performing mental arithmetic and watching relaxation movie respectively. In this method, the mental and physiological condition was assessed using only 20 regressive heart beats, so this method is considered as the real time assessment method.
SMDs (Surface-Mounted Devices) are positioned or inspected using image processing methods, in chip mounters, used to place SMDs on PCBs (Printed-Circuit Boards), as well as in SMD inspection system. Currently, such methods require Part Shape Data made by time-consuming manual operation. Therefore, the demand for shortening the production lead-time grows by automation. In this paper, we propose a system for the hierarchical automatic classification of SMDs. We used Pixel Frequency, Edge Frequency and Circularity for feature extraction. We register the features of the image of the SMDs as reference data. We proposed the method for hierarchical classification. We classify the parts according to the relative histogram of circularity with the discriminant analysis as 1st classification. We classify the parts according to the rule base as 1st class segmentation. We classify the parts according to the DP (Dynamic Programming) distance, calculated using the reference data, with the discriminant analysis as 2nd classification. We evaluated this classification method with 715 parts, and obtained a classification rate of 95.9%.
In developing an automation in processes, a demand for compact and simple distance measurement is increasing. A compact distance meter based on self-coupling effect of semiconductor laser has been studied. It is a compact and simple sensor with high accuracy as it consists of only a laser and a lens. However, a measurement error of this distance meter increases due to mode hop of FP type semiconductor laser. In this paper, a distance meter based on self-coupling effect using VCSEL is studied. It is confirmed that the mode hop for VCSEL does not happen and the distance meter using VCSEL can measure a distance. Furthermore, the distance meter using VCSEL with less optical output power can measure longer distance than that using FP laser.
Digital signal processing (DSP) has been widely used because it can realize variety of functions by change of software. Now, it is possible to handle practical analog or digital signal by DSP. This paper proposes a new method for reception of AM & FM broadcast signal using FFT/IFFT. Also, demultiplexing of demodulated FM signal is included. First, input signal is sampled and truncated. Then, truncated samples are transferred to frequency domain samples by FFT. Demodulation and demultiplexing are performed using both frequency domain and time domain samples. In order to process continuous signal by truncated samples, use of overlap and save method is assumed. Matlab Simulink diagram of demodulation and demultiplexing by the proposed method is also presented.
Recently, systems become complicated for aiming at their high performance in various fields. With increasing of complexity of systems, quantity of their wiring becomes enormous. We have been developed researches for reducing quantity of wiring by using unique spread spectrum (SS) technique with only gate switching. The SS method can be applied directly in power electronics systems. In this paper, we show the proposed SS method which is non-interference between channels. Next, we compare the error rate of proposed SS method to that of usual SS method using M-sequence code. Based on these fundamentals, we construct multiple power transmission system of 7 channels in which 7 EX-NOR gates and 7 analogue gates are used for modulation and demodulation respectively. In this system power with informations are transmitted with no interferences between channels, and it is successful to regenerate power for controlling each load.
In quantum information theory, there is superadditivity in capacity of a quantum channel as special property. We showed the calculating method of mutual information analytically for binary linear codes by using Square-root measurement as decoding process. Therefore, many examples of codes which shows existence of superadditivity in capacity have been given. But the scope of method was not clarified. In the present paper, we show the method can be applied to any binary linear codes. Moreover, we show quantum channel capacity is almost attained in finite codeword length by using approximation to simplex code.
Speech recognition systems have come to be used widely. When any speech recognition system is disturbed by surrounding noises, considerable reduction in the recognition rate is inevitable. It is much desired to develop noise reduction methods so that any speech recognition system can be used in realistic environments. We propose a novel scheme especially effective for reducing the noise generated in the vehicles. The reduction is achieved through image processing techniques applied to the corresponding spectrograms. Experiments have been conducted on speech sounds in the vehicles. The performances have been evaluated in terms of the output signal-to-noise ratio (SNR). The proposed scheme has been compared with the conventional spectral subtraction method, and found to be promising especially for speeches corrupted with great amount of car noises.
The estimation of 3D human pose from a single image can be implemented in the way of large-scale image retrieval. For a given input image, a few similar images are retrieved from the database consisting of human figure images annotated with 3D human poses; then the 3D poses corresponding to retrieved images serve as the pose estimates. This method is simple but works if two conditions are met: (i) sufficient data and (ii) a good image matching algorithm. Sufficient data can be generated by using 3D character rendering software and various human motion data. As for matching algorithm, here we employ the chamfer distance which has proved to be an effective tool in many related works. However, applying the chamfer distance to large-scale problem would lead to high time requirements. Thus, here we propose an efficient approximate chamfer distance which uses the subspace representation of Distance Transform (DT) in computing chamfer distance so that the major computation can be done offline. We show in experiments that the approximate chamfer distance achieved competitive estimation performance but over three hundred times speedup gain in comparison with the exact chamfer distance.
Nowadays, driving support systems, such as car navigation systems, are getting common and they support drivers in several aspects. It is important for driving support systems to detect the state of drivers' consciousness. Particularly, detecting drivers' drowsiness could protect drivers from danger of collisions caused by drowsy driving. In this paper, we discuss a system and a method for detecting driver's drowsiness, which use a property of blink waveforms that drivers' eye-closing time is strongly connected to their drowsiness. Moreover, our system detects the drowsiness robustly for individual differences by using three factors extracted from the individual blink waveform.
Gain-scheduling control is one of effective methods for plants whose dynamics changes significantly according to its operating point. A frozen parameter method is known to be a practical gain-scheduling controller synthesis, which interpolates the controllers designed at the prespecified (frozen) operating points according to the current operation point. Hyde et al. proposed a gain-scheduling control that H∞ loop shaping procedure is adopted as a controller synthesis at each operating point. H∞ loop shaping procedure is based on loop shaping of an open loop characteristic by frequency weights and is known to be effective for plants with bad condition number. However, weight selection satisfying control specifications is hard job for a designer. This paper describes the design of a suboptimal weight and a controller by means of algorithm that maximizes the robust stability margin and shapes the open loop characteristic into the desired shape at each operating point. Moreover, we formulate a weight optimization problem as a generalized eigenvalue minimization problem, which reduces the designer's burden of weight selection. Finally, we realize robust and high performance control system by scheduling both weights and controllers. The effectiveness of the proposed control system is verified in terms of the achieved robust stability margin and experimental time responses of a rotary inverted pendulum which involves strong nonlinear dynamics.
This paper presents a new design method of servo control system based on a dual observer for the positioning of flexible structures. In order to reduce the sensor costs and to suppress spillover phenomena which are caused by ignored elastic modes of the plant, we introduce an input pre-filter which possesses low pass characteristics. First, we consider a generalized plant, which is formulated as an augmented system which is expressed by the plant, the pre-filter and an integrator based on Internal Model Principle. Second, we expand the input spaces of the generalized plant by using the dual observer for matching to desired models. Third, we show our proposed design method which satisfies the design specifications. Finally, some results of numerical simulations are given in order to verify the usefulness of our method.
In this paper, we propose a method to abstract human manipulation skill, which can be useful in systems of machine intelligence and human operator assistance. It is, however, not easy to model human operation by traditional methods due to the lack of good physical models for human skill, In our approach, human manipulation skill is considered as a hybrid dynamical system (HDS). Specifically, a hinging hyperplane autoregressive exogenous (HHARX) model is employed as it is able to deal with manipulation modes and switches among them simultaneously. Such an HHARX model can be obtained by system identification via mixed-integer linear programming (MILP). As a typical example, we apply our approach to an automatic driving system of a small radio-controlled vehicle. Both simulation and experimental results illustrate the effectiveness of the proposed method.
Entanglement of formation (EoF) for a quasi-Bell state degraded by an attenuation channel is computed. As a result, it is clarified that EoF for a quasi-Bell state is greater than that for the Bell states.
In this study, we proposed a time-domain measurement method of moving object speed with a commercially available acceleration sensor. The sensor of this kind is normally used to measure the acceleration of a stationary vibration object, while it is not applicable to the measurement of a transient moving object due to the frequency response of the sensor itself. An impulsive sensor response was derived from the free-drop movement of a metallic sphere. The deconvolution allows the sensor to measure the acceleration in the time domain, which was validated through the measurement of the speed of a hand-held metal piece approaching a target.
The transparent polymer light emitting device (TPLED) utilizing MEH-PPV that has the characteristics of transparency to visible range of light. By the insertion of BCP as an electron transport layer, the carrier and exciton were confined to enhance the recombination-rate, and BCP acts as a protecting layer from sputtering damage. Moreover, by alkali metal doping of the BCP, electron injection of the TPLED was improved. The device showed 70 % transparency at 590 nm, and the energy conversion efficiency from both surfaces of the device was 0.1 lm/W.
This paper explores the development of a real time intelligent surveillance system using the technology of pattern recognition based on independent component analysis (ICA) and a novel matching method as a reaction to perceptions of insecurity in sensitive spaces. An array of motion images of people are caught by micro digital cameras on board and transferred through wireless network to FPGA board. The feature points of the shot image and the image in database are extracted out using ICA algorithm in embedded PowerPC. The most similar images are picked up from the image database, which is classified to different clusters, and the potential insecurity level of invaders is detected. Furthermore the respective locations are connected by wireless network. The system of hardware and software co-design is implemented on Xilinx FPGA with the performance of high efficiency, low power consumption and easy integration with other devices.
Road scene analysis in 3D driving environment, which aims to detect objects from continuously changing background, is vital for driver assitance system and Adaptive Cruise Control (ACC) applications. Laser or millimeter wave radars have shown good performance in measuring relative speed and distance in highway driving environment. However the accuracy of these systems decreases in an urban traffic environment as more confusion occurs due to the factors such as parking vehicles, guardrails, poles and motorcycles. A stereovision based sensing system provides an effective supplement to radar-based road scene analysis with its much wider field of view and more accurate lateral information. This paper presents an efficient solution for road scene analysis using a trinocular stereo vision based algorithm. In this algorithm, trinocular stereo vision detects all types of objects in road scene. And “U-V-disparity" concept is employed to analyze 3D geometric feature of road scene. The proposed algorithm has been tested on real road scenes and experimental results verified its efficiency.
In this paper, we propose a new global optimization method “Draining Method” which uses a tuning of the bifurcation characteristic of the discrete gradient chaos model by an objective function transformation. Specifically, firstly, we show that a local minimum, to which the chaotic orbit converges with the chaos annealing, is dominated by its bifurcation characteristic from its stability analysis. From this consideration, a tuning method of the bifurcation characteristic which takes into consideration the objective function value of each local minimum is proposed. In this method, the landscape of objective function is transformed into flat in an area whose objective function value is lower than a certain threshold value, and thereby the search point with the chaotic motion is made stable and unescapable from this area. Finally, we propose an optimization method which brings the search point close to a global minimum by gradually decreasing the threshold value (we call this decrease procedure “Draining”), confining the search point to the area where the objective function value is lower. We confirm effectiveness of our proposed model through applications to several benchmark problems whose dimension of variable is high and landscape has multi-peaks.