電気学会論文誌C(電子・情報・システム部門誌)
Online ISSN : 1348-8155
Print ISSN : 0385-4221
ISSN-L : 0385-4221
125 巻 , 9 号
選択された号の論文の27件中1~27を表示しています
特集:生命・生体系のモデル
特集論文
<医用電子・生体工学>
  • Takanori Uchiyama, Ryusei Uchida
    2005 年 125 巻 9 号 p. 1376-1381
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    The purpose of this study is to develop a new modeling technique for quantitative evaluation of spasticity in the upper limbs of hemiplegic patients. Each subject lay on a bed, and his forearm was supported with a jig to measure the elbow joint angle. The subject was instructed to relax and not to resist the step-like load which was applied to extend the elbow joint. The elbow joint angle and electromyogram (EMG) of the biceps muscle, triceps muscle and brachioradialis muscle were measured. First, the step-like response was approximated with a proposed mathematical model based on musculoskeletal and physiological characteristics by the least square method. The proposed model involved an elastic component depending on both muscle activities and elbow joint angle. The responses were approximated well with the proposed model. Next, the torque generated by the elastic component was estimated. The normalized elastic torque was approximated with a dumped sinusoid by the least square method. The reciprocal of the time constant and the natural frequency of the normalized elastic torque were calculated and they varied depending on the grades of the modified Ashworth scale of the subjects. It was suggested that the proposed modeling technique would provide a good quantitative index of spasticity as shown in the relationship between the reciprocal of the time constant and the natural frequency.
  • Naoki Kodama, Hiroshi Takeuchi
    2005 年 125 巻 9 号 p. 1382-1386
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    We assessed relationships between six texture features and changes in atrophy of the cerebral parenchyma, the hippocampus, and the parahippocampal gyrus in the Alzheimer-type dementia (ATD) brain to determine whether or not the features reflect cerebral atrophy in ATD patients. The subjects of this study were 10 ATD patients, and underwent an magnetic resonanse imaging test of the head annually for at least 3 consecutive years. They consisted of three men and seven women, with a mean age of 71.4 ± 6.7 years. The results of study, the mean run length nonuniformity (RLN), angular second moment (ASM), and contrast (CON) increased with time, whereas the mean gray level nonuniformity (GLN), run percentage (RPC), and entropy (ENT) decreased with time. There was a statistically significant correlation between brain-intracranial area ratio (BIR) and GLN (p = 0.039), between BIR and ASM (p = 0.011), and between BIR and ENT (p = 0.023) as well as between parahippocampal-intracranial area ratio and GLN (p = 0.049). These results indicate that the six texture features were shown to reflect gray matter atrophy associated with ATD and to change with the progress of the disease. Although the course of ATD can be followed up by measuring a hippocampal area or volume and determining a decrease in the area or volume, texture features should be a more effective instrument for identifying the progress of ATD.
  • Osamu Sakata, Kensuke Okada, Kaoru Kohyama, Tsuyoshi Shiina, Yoichi Sa ...
    2005 年 125 巻 9 号 p. 1387-1392
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    There are many fluctuations in life phenomena, and they are always occurring in a human brain. Although we developed a method called multidimensional directed information (MDI) analysis to visualize information flow in a human brain, it was based on the presumption that the information propagation time is constant. This paper reports how the method has been improved so that it may have applicability even when information propagation time fluctuates. First, we conducted a numerical simulation to investigate characteristics of the new method, and we confirmed that the new MDI analysis is beneficial in calculating the amount of information flow. Next, we adapted the new method to an electroencephalogram (EEG) analysis. As a result, we were able to estimate the amount of information flow between EEGs of a normal subject.
  • Tadanori Fukami, Yusuke Koyanagi, Yukinori Tanno, Takamasa Shimada, Ta ...
    2005 年 125 巻 9 号 p. 1393-1398
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    In this research, we estimated temporary change of brain activities in auditory oddball paradigm by moving an analysis time window. An advantage of this method is that it can acquire rough changes of activated areas even with data having low time resolution. Eight normal subjects participated in the study, which consisted of a random series of 30 target and 70 nontarget stimuli. We investigated the activated area in three kinds of analysis time sections, from stimulus onset to 5 seconds after the stimulus (time section A), from 2 to 7 seconds after (B) and from 4 to 9 seconds after (C). In time section A, representative activated areas were regions including superior temporal gyrus centered around inferior frontal gyrus, left precentral gyrus corresponding to Broadmann area 6 (BA 6), right fusiform gyrus corresponding to BA 20, bilaterally medial frontal gyrus and right inferior temporal gyrus were activated. In B, we could see the activations in bilatelally cerebellum, inferior frontal gyrus, and region including left motor area. In C, bilatelally postcentral gyrus, left cingulate gyrus , right cerebellum and right insula were activated. Most activations were consistent with previous studies.
  • Kai Sheng, Keisuke Kameyama, Kazuo Toraichi, Yoshinori Mitamura, Kazuk ...
    2005 年 125 巻 9 号 p. 1399-1407
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    When digitized fundus images are used in medicine, important information for clinicians' diagnosis should be maintained well after scaling. Conventional scaling methods select the interpolation kernel based on Shannon's sampling theorem which is only appropriate for band-limited signals and usually generate image with jaggy noise or blurred blood-vessel shapes that the tortuosity and diameter change of blood vessels which are important information to clinicians' diagnosis can not be maintained clearly. To solve these problems, we select the quadratic Fluency sampling function as the interpolation kernel to maintain the color reality of fundus image based on the Fluency information theory. Scaling is then realized by interpolation directed to the blood-vessel shape map of required resolution which is generated from two kinds of Fluency sampling functions. These two kinds of Fluency sampling functions are precedingly utilized to approximate shapes of blood vessels on the original fundus image according to the suggestion of specialists in fundus field. Resulting images by the proposed method show good shape maintenance of blood vessels and have a better quantitative evaluation than the generally recognized best conventional method.
論文
<電子・集積回路>
  • Kei Eguchi, Shinya Terada, Fumio Ueno, Hongbing Zhu, Toru Tabata, Taka ...
    2005 年 125 巻 9 号 p. 1408-1415
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    A step-down DC-DC converter with charge-average processes is proposed in this paper. The converter is designed by using switched-capacitor (SC) techniques. Different from conventional converters such as a series-parallel type power converter and a Dickson-type power converter, the ripple noise of the proposed converter is small, because the output voltage is always obtained irrespective of the states of the clock pulses. The output voltage of the proposed converter is expressed by (Q/P) × Vin (P ∈{1, 2,..., N} and Q∈{1, 2,..., N}). Furthermore, when the number of the capacitors is small, the hardware-cost for the proposed circuit is less than that for the conventional converters such as a series-parallel type power converter and a ring-type power converter. Concerning 3-stage power converters, SPICE simulations are performed to confirm the validity of the circuit design. For the input voltage 3.6 V, the power efficiency of the proposed circuit is 92.7 % in the output current about 320 mA.
<医用電子・生体工学>
  • 齋藤 大輔, 斎藤 恵一, 納富 一宏, 斎藤 正男
    2005 年 125 巻 9 号 p. 1416-1421
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    This paper presents the visibility ordering of several web safe colors. The research of web page visibility is important because of the rapid dissemination of the World Wide Web. The combination of a foreground color and a background color is an important factor in providing sufficient visibility. Therefore, the rating of color combination visibility is necessary when developing accessible web sites. In this study, the visibility of several web-safe color combinations was examined using psychological methodology, i.e., paired comparison. Eighteen chromatic and 3 achromatic web-safe colors were employed for visual stimuli. Twenty-eight subjects ranging from ages 21 to 75 were recruited, and all were with normal color sensation. They looked at two different colored characters simultaneously on the white background and were instructed to identify which one enabled them to see more clearly. In examining the relationship between the psychological rankings of the color combinations and the visual sensations, each color combination was first scored as to the visibility by Thurstone's paired comparison technique. Secondly, the visual sensation was deduced by applying Weber-Fechner's law to the luminance of the foreground colors. As results, the luminance of a foreground color influenced the visibility; however the visibility rating is difficult only using the luminance of web-safe colors. These indicate that the chromaticity and chroma saturation are necessary in rating of chromatic web-safe color visibility.
<通信・ネットワーク>
<音声画像処理・認識>
  • 白澤 洋一, 西田 眞, 西 健治
    2005 年 125 巻 9 号 p. 1430-1437
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    This paper proposes a method for extracting the lip shape from the region around the lip. It is carried out without limited conditions such as the lipstick or lighting. The proposed method uses color information for the lip shape extraction. They are psychometric quantities of a metric hue angle (hab), a rectangular coordinates(a*) , which are defined in CIE 1976 L*a*b* color space. The method employs fuzzy reasoning was employed in order to consider obscurity in image data such as shade on the face. The membership function of condition part for characteristics in each class was defined by the triangular membership function was used for the fuzzy reasoning. In order to reduce the effect of the data acquisition condition, an extraction method is here presented for the lip shape from region around the lip due to fuzzy reasoning. We studied on set up of the membership function of condition part. The proposed method uses a* color histogram and habcolor histogram of the region around the lip when sets up of membership function of condition part.
    This paper clarified that the lip was able to be extracted without the no special conditions such as the lipstick or lighting. The experimental result indicates the effectiveness of the propose method; about 98.7 percent of facial images data was extracted its shape.
  • 瀬川 修, 武田 一哉
    2005 年 125 巻 9 号 p. 1438-1443
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    We have developed an information retrieval system for telephone dialogue in load dispatch center. In load dispatching operations, the needs for recording and information retrieval of a telephone dialogue are high. The proposed system gives a solution for the task and realizes an information retrieval function with any keywords. The effectiveness of the system is verified by the telephone dialogue transcription and information retrieval experiments. With 30 telephone dialogue in a load dispatch center, we obtain 59.5% in average word correct and 44.4% in average word accuracy. In the information retrieval experiment, with 20 keywords, we obtain 87.3% in average precision and 67.2% in average recall.
  • 東山 和弘, 小野 智司, 王 宇, 中山 茂
    2005 年 125 巻 9 号 p. 1444-1454
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    This paper proposes a method for Japanese finger character recognition, using a 3-dimensional (3D) scanner. A hand is a complex dexterous manipulator, evolved to be more complex than any other animals. The hand, being capable of making many different complex shapes, it is ideal for communicating using gestures. The recognition of a whole language, such as the Japanese finger characters, requires the differentiation of subtle similar positioning of each digit. To know the exact 3D position of the hand's digits and overall shape, data gloves had been developed, but these are inconvenient to use. 2D image recognition systems struggle with recreating the 3D information. To capture the 3D information, the proposed method uses a 3D scanner, and then makes matches with 3D templates representing each unique character. Experimental results show that the proposed method recognizes a greater number of characters than existing 2D-based systems with recognition accuracy, on average of 93% for 9 testees, and a peak of over 98% for 4 of them.
  • 椎屋 和久, 内村 圭一, 泉田 喜一郎, 杉田 憲幸, 寺田 聖央
    2005 年 125 巻 9 号 p. 1455-1463
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    This study is concerned with detection of objects in motion from time serial pictures of a 6-D of freedom motion monocular camera. As a point in real space throw an image on corresponding pixels of time serial pictures. So to solve this problem to find out the corresponding algorithm is essential. In this paper we proposed a new method of the detection of motion objects based on compensating background image shift caused by camera rotation and translation. The main point of this idea is, to take three pictures by the passive sensor (CCD camera) in three different times tk, tk1 and tk2 while the platform is moving, by correcting them rotationally (also called vertical rectification) the rotation disparity will be excluded, and we get three parallel frames that will be matched through their geometrical constraint for the translation-distortion extraction.
  • 伊藤 征嗣, 吉岡 理文, 大松 繁, 北 耕次, 久後 耕一
    2005 年 125 巻 9 号 p. 1464-1469
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    An image segmentation is an important subject for an image recognition. In this paper, we propose a new image segmentation method for scene images. The proposed segmentation method classifies images into several segments without using the Euclidian distance. We calculate the histograms of the image for each component of HSI color space, and obtain three results of the image segmentation from each histogram. We consider the achromatic colors to decrease the number of regions. We compare the results of the proposed and the k-means methods in order to show the effectiveness of the proposed method.
  • 辛 貞殷, 小澤 慎治
    2005 年 125 巻 9 号 p. 1470-1475
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    The purpose of this research is to recognize 3D shape features of a human body automatically using a 3D laser-scanning machine. In order to recognize the 3D shape features, we selected the 23 feature points of a body and modeled its 3D features. The set of 23 feature points consists of the motion axis of a joint, the main point for the bone structure of a human body. For extracting feature points of object model, we made 2.5D templates neighbor for each feature points were extracted according to the feature points of the standard model of human body. And the feature points were extracted by the template matching. The extracted feature points can be applied as body measurement, the 3D virtual fitting system for apparel etc.
  • 雨森 道紘, 横水 伸行
    2005 年 125 巻 9 号 p. 1476-1480
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    This paper presents an innovative approach for quality sorting of objects such as apples sorting in an agricultural factory, using an image processing algorithm. The objective of our approach are; firstly to sort the objects by their colors precisely; secondly to detect any irregularity of the colors surrounding the apples efficiently. An experiment has been conducted and the results have been obtained and compared with that has been preformed by human sorting process and by color sensor sorting devices. The results demonstrate that our approach is capable to sort the objects rapidly and the percentage of classification valid rate was 100 %.
<制御・計測>
  • 久保 和良
    2005 年 125 巻 9 号 p. 1481-1490
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    The Prony's method is an approximation approach to decomposing a function into sum of exponents, and thus, is applicable to unknown frequencies estimation of signals. The concrete algorithms for estimating pure sine-wave, triple-tone, and quadruple-tone have already been derived and presented. This paper aims at deriving the estimating algorithm for multi-sine signals which consist of unknown sine-waves.
    The new method of generating algebraic algorithm for detecting unknown frequencies in the signals is derived by mathematical induction. The crux of the generation is depending on the integer matrices induction. A handy method for generating the matrices is shown as well. Algorithms for the triple-tone, quadruple-tone and the higher order tone are generated and verified. As a result, they are shown to be identical with the ordinary algorithms.
    Subjects on the application of the induced algorithm to practical frequency detection are discussed. The algorithm has both instantaneity in time domain and higher resolution in frequency domain, that is, the signal analysis by the algorithm can be performed without constraint of the uncertainty principle. Iterative solution for algebraic equation is dominant for calculation in the algorithm. Techniques for detecting frequencies in a multi-sine of unknown order are also discussed.
  • 東 剛人, 藤田 常利, 藤田 政之
    2005 年 125 巻 9 号 p. 1491-1496
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    The purpose of this paper is to design congestion controllers for TCP/AQM networks using state predictive control and illustrate the effectiveness of designed congestion controllers via SIMULINK and the ns-2 simulator. Linearized models of TCP/AQM networks can be described as linear systems with an information delay simply. Using state predictive control, these linear systems with an information delay is equivalent to linear systems with no delays. Thus congestion controllers (AQM mechanisms) can be designed using the linear control theory. In this paper, LQ control with an observer is adopted for linear systems with no delays which describe linearized systems of TCP/AQM networks. Finally the designed state predictive controllers using LQ control with an observer is implemented and some simulation results are shown via SIMULINK and the ns-2 simulator.
<システム>
  • 末田 統, 藤澤 正一郎, 王 欣
    2005 年 125 巻 9 号 p. 1497-1502
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    An experiment to evaluate a tactile walking surface indicator for visually impaired persons was usually carried out in the outdoor environment, and the weather and the seasons affected on the schedule and the result. We constructed the evaluation system within the building so we could conduct walking experiments that were unaffected by the weather regardless of the four seasons. The subjects of this system were not only a visually impaired person and a sighted deaf person but also general person. The laboratory provided a soundproof and shaded structure consisting of the walls and the ceiling. External sound and light were blocked. The hue could be adjusted by three-color fluorescent lamps, and the light could be adjusted from daytime brightness to a dim moon light. Research into the walking of visually impaired persons at nighttime is a pressing problem as the barrier-free transportation law has been enacted in Japan. An international standard has been discussed, and a scientific basis for that standard is now required.
研究開発レター
<光・量子エレクトロニクス>
  • 水本 巌, 小竹 外治, 益子 信郎, 鈴木 喜隆
    2005 年 125 巻 9 号 p. 1503-1504
    発行日: 2005年
    公開日: 2005/12/01
    ジャーナル フリー
    The optical CT unit which was assembled with the laser diode working at the wavelength of 1.3 μm, and a glass optical fiber and a pin-hole with a diameter of the 100 μm yields the collimated near-infrared light through a scattering medium. Because the spatial collimator system needs no fast response time, a high sensitive Ge-PIN photodetector was employed the CT system. The optical CT image is allowed by use of near-infrared absorption characteristic. When the image construction of a grape was performed using projection data, so the comparatively good experimental results was obtained. The places of a grape seed was found without cutting. By means of the difference in characteristics of near-infrared absorption, the image of a cylindrical oil phantom in gelatin was reproduced.
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