共查询到20条相似文献,搜索用时 15 毫秒
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基于微焦点X射线源的相位衬度成像实验研究 总被引:1,自引:0,他引:1
对弱吸收、低密度、较轻元素物质来说,传统的X线吸收成像方式存在分辨能力低、成像效果差等问题,而X线相位衬度成像恰好可以弥补这些缺点。以微焦点X射线源为基础,选择了两种具有明显上述特征的样品,采用类同轴相衬成像的方式设置实验参数。实验不仅能得到清晰、放大的图像,而且能够明显突出样品的边界信息,从而验证了X线的相位衬度成像效果。 相似文献
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Ling Wang Jianming Lu Yeqiu Li Takashi Yahagi Takahide Okamoto 《Electrical Engineering in Japan》2008,163(3):37-46
Many important problems in engineering and science are well‐modeled by Poisson noise, and the noise of medical X‐ray images is Poisson noise. In this paper, we propose a method for noise removal for degraded medical X‐ray images using improved preprocessing and an improved BayesShrink (IBS) method in the wavelet domain. First, we preprocess the medical X‐ray image. Second, we apply the Daubechies (db) wavelet transform to medical X‐ray images to acquire scaling and wavelet coefficients. Third, we apply the proposed IBS method to process wavelet coefficients. Finally, we compute the inverse wavelet transform for the threshold coefficients. Experimental results show that the proposed method always outperforms traditional methods. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(3): 37– 46, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20486 相似文献
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Application of dynamic counter circuits in programmable digital pixel sensor architectures 下载免费PDF全文
M. Habibi 《International Journal of Circuit Theory and Applications》2014,42(10):989-1005
In this paper, a high dynamic range digital pixel sensor (DPS) is presented. Each pixel receives light illumination and converts the intensity level to a digital code. The analog‐to‐digital conversion is performed in‐pixel. The pixel structure incorporates light to pulse signal converter and compact in‐pixel dynamic counter to convert the pulse signal to binary coded data. Different variations of the custom design dynamic counters are analyzed in a 0.18 µm technology, and their application in the DPS is investigated. It is shown that due to the limited clock frequency required in the sensor pixel, the dynamic counter can be incorporated as a pulse to binary code converter. Performance specifications such as power consumption, dynamic range and resolution of the presented structure are investigated using a 100 × 100 pixel sensor. The presented sensor is an effective solution for use in digital field programmable smart image sensors and vision chips since the pixel output is a regular binary code while no global digital counter bus is required. The fill factor of the presented design remains close to that of typical DPSs. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Hidekuni Takao Radhakrishna Vatedka Yoshiaki Ito Fumihito Komakine Kolelas Serge Kazuaki Sawada Makoto Ishida 《IEEJ Transactions on Electrical and Electronic Engineering》2008,3(3):274-280
In this paper, CMOS‐based low‐noise amplifiers with JFET‐CMOS technology for high‐resolution sensor interface circuits are presented. A differential difference amplifier (DDA) configuration is employed to realize differential signal amplification with very high input impedance, which is required for the front‐end circuit in many sensor applications. Low‐noise JFET devices are used as input pair of the input differential stages or source‐grounded output load devices, which are dominant in the total noise floor of DDA circuits. A fully differential amplifier circuit with pure CMOS DDA and three types of JFET‐CMOS DDAs were fabricated and their noise performances were compared. The results show that the total noise floor of the JFET‐CMOS amplifier was much lower compared to that of the pure CMOS configuration. The noise‐reduction effect of JFET replacement depends on the circuit configuration. The noise reduction effect by JFET device was maximum of about − 18 dB at 2.5 Hz. JFET‐CMOS technology is very effective in improving the signal‐to‐noise ratio (SNR) of a sensor interface circuit with CMOS‐based sensing systems. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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Marengo S. Pepin C. Goulet T. Honde D. 《IEEE journal of selected topics in quantum electronics》1999,5(4):895-901
We have developed an optical system that simultaneously selects and amplifies photons in a time window of less than 10 ps. This new subpicosecond optical amplifier allowed us to realize one-dimensional images of a striped pattern with a spatial resolution of 200-μm through a 30-mm liquid scattering medium. Monte Carlo simulations were performed to study the relative importance of parameters characterizing the medium and the time-gated amplifying system in relation to the image sharpness. The potential application of this system in medical imaging is discussed 相似文献
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Tatsuji Matsuura 《IEEJ Transactions on Electrical and Electronic Engineering》2016,11(5):535-548
Recent progress in CMOS integrated successive approximation (SAR) analog‐to‐digital converters (ADCs) is remarkable in terms of architecture and performance. Because of the inherent non‐necessity of active circuit elements such as operational amplifiers, the SAR architecture is suitable for fine CMOS processes. By using a time‐interleaved architecture, it achieves a very high speed conversion rate of 90 G‐sample/s with an 8‐bit resolution. Also, for applications with very low power consumption, such as wireless sensor nodes, it achieves 84 nW at 10‐bit, 200 k‐sample/s. A high signal to noise and distortion ratio (SNDR) can also be achieved by using several techniques such as an SAR architecture that combines oversampling and noise shaping. This survey paper explains the progress made recently in SAR‐ADC circuit techniques and the achieved performances. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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Cihun‐Siyong Alex Gong Kai‐Wen Yao Muh‐Tian Shiue 《International Journal of Circuit Theory and Applications》2013,41(3):238-258
We developed an inductively powered integrated electronic prosthesis, allowing for the trade‐offs among implant functionality, circuit complexity, power consumption, hardware cost, and integrity of data recovery, for a multichannel microstimulation circuitry. The proposed prosthesis features energy efficiency and is capable of up to 40 scan/s with 240 stimulus channels in mode I and three times resolution at the same scan rate in mode II under a carrier frequency of 2 MHz. In order to satisfy future upgrade demands, the prototype has been constructed with a 16‐channel‐based stimulation scheme so that the spatial resolution of the design can be extended toward various experimental purposes. The circuit techniques used in the system are detailed. Results from fabricated chips using a 0.18‐µm CMOS process are given as proof of concept. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Dejian Wang Yoichi Kageyama Makoto Nishida Hikaru Shirai Asana Motozawa 《IEEJ Transactions on Electrical and Electronic Engineering》2013,8(6):627-633
In recent years, remote sensing has been used to assessing water pollution distribution. In this study, water quality is analyzed using data collected by the Advanced Visible and Near Infrared Radiometer type‐2 (AVNIR‐2) of the Advanced Land Observing Satellite (ALOS) at various points in time. We carried out fuzzy regression analysis of the AVNIR‐2 data and direct measurements of local water quality. The relationship between the water quality data and the AVNIR‐2 data was analyzed by solving both the min and max problems. By comparing the maps of estimated water quality with actual distributions of water quality in the study area, we found that the method used in this study allows effective derivation of water quality conditions from AVNIR‐2 data, which provides 10‐m spatial resolution. Furthermore, by comparing the maps created using AVNIR‐2 data collected at different times, we obtained results suggesting temporal changes in water quality. We also compared the results obtained using data collected by the optical sensor of the Landsat thematic mapper (TM) with 30‐m resolution and those obtained using data collected by the active sensor of JERS‐1 synthetic aperture radar (SAR), and examined the differences in classification results resulting from differences in resolution and sensors. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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《IEEJ Transactions on Electrical and Electronic Engineering》2017,12(1):140-146
This paper presents a 60‐GHz power amplifier with on‐chip varactor‐based tunable load‐matching networks and an embedded DC temperature‐sensor‐based power detector. The output power can be monitored by the DC temperature sensor, and load‐matching network can be tuned by regulating the control voltage of the varactors, which can be used for correcting unpredictable process, supply voltage, and temperature (PVT) variations and load mismatch. Measured results show that the small‐signal gain of the CMOS power amplifier is up to 6.5 dB at 52 GHz. The power amplifier achieves 5 dBm output P1dB and 7 dBm saturated output power with 4.5% maximun power added efficiency (PAE) at 1 V control voltage. By sweeping the control voltage of the varactors, the power amplifier can obtain the maximun power gain, which can be used to solve the load mismatch. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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Atsushi Teramoto Takayuki Murakoshi Masatoshi Tsuzaka Hiroshi Fujita 《IEEJ Transactions on Electrical and Electronic Engineering》2007,2(2):195-197
Chip components mounted on the printed circuit board are rapidly being miniaturized. Furthermore, the fillet‐less chip soldering technique, which does not use a solder fillet, is widely used in portable products such as mobile phones. However, there is no method to inspect the soldering of fillet‐less chip mounting. In this paper, we propose an automated X‐ray inspection technique for fillet‐less chip mounting. It extracts three inspection parameters from the X‐ray image. In the experiments, we evaluate the repeatability and inspecting ability of the technique and confirm that sufficient information for failure detection is obtained. An automated X‐ray inspection system using this technique is now in operation at some factories, so in conclusion our automated method would be useful in practice. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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Hongbing Zhang Kazutaka Mitobe Mahmudul Kabir Masafumi Suzuki Yoko Mitobe Tomonori Habuchi Noboru Yoshimura 《IEEJ Transactions on Electrical and Electronic Engineering》2012,7(Z1):S126-S131
We have successfully achieved terahertz imaging of cellulose acetate membrane electrophoresis of egg albumin using continuous‐wave imaging at 0.189 THz. A sample holder has been devised that can eliminate the membrane crook generated in the drying process after electrophoresis. A probe has been also fabricated, which was assembled with a Schottky barrier diode detector to detect the terahertz signal. A higher spatial resolution of 0.3 mm was achieved, which is 6.83 times the 2.05‐mm resolution without using the probe. Terahertz images of cellulose acetate membrane electrophoresis of egg albumin of 2 µl was obtained, in which the positions of protein were perfectly in accordance with the stained images. The technology can be used instead of the staining method for cellulose acetate membrane electrophoresis. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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High‐performance drive of synchronous motors such as a permanent magnet synchronous motor and a synchronous reluctance motor can be achieved by current vector control. In such drive systems, the armature current is controlled as a sinusoidal waveform based on rotor position information from a high‐resolution position sensor, and the current vector (d‐ and q‐axis currents) is suitably controlled by current feedback control. This paper proposes a current sensorless drive system with a low‐resolution position sensor in order to simplify the SM drive system. High‐performance current control is achieved in the proposed drive system, where the current sensors are eliminated and the simulated currents are used for current control. The low‐resolution position sensor is used instead of a conventional high‐resolution position sensor, and the higher position information is estimated. The steady‐state and transient characteristics are examined in several experiments with respect to the synchronous reluctance motor and the interior permanent magnet synchronous motor. It is confirmed that sinusoidal current drive, high‐performance current vector control, and speed control can be achieved by the proposed drive system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 34–43, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10072 相似文献
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Makoto Souwa Daichi Yamazaki Michio Okada Akitaka Yoshigoe Yuden Teraoka Toshio Kasai 《Electrical Engineering in Japan》2011,175(4):43-47
We report the results of a study of the natural oxidation of Cu3Au(110) with high‐resolution X‐ray photoemission spectroscopy in conjunction with synchrotron radiation. The clean surface of Cu3Au(110) is terminated with 50% Au and 50% Cu atoms. After natural oxidation in the air, Cu atoms segregate on the surface and produce Cu‐oxide. As a result, Au atoms move into the bulk. Au atoms below the oxide reduce the diffusion of O atoms farther into bulk and limit the oxide thickness. The face dependence of natural oxidation indicates that the diffusion of Cu atoms also contributes to oxide formation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 43–47, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21149 相似文献
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Masood Teymouri 《International Journal of Circuit Theory and Applications》2020,48(11):1887-1899
A complementary metal oxide semiconductor (CMOS) image sensor with a resolution of 128 × 128 pixels is presented in this paper in which pixel signal readout, noise suppression, and comparing operations are performed by one circuit during two steps: reading and conversion. The main idea of this work is to combine three main operations of an image sensor in one circuit. This method helps to decrease power consumption, silicon area, total noise, and imaging time. The total power consumption of the imager is 11 mW with a 2.5-V power supply and 40-fps frame rate. The pixel layout size is 10 × 10 μm2 with a fill-factor of 81%. The analog to digital converter (ADC) resolution is 10 bits, and the error resulted from the proposed circuit is about ±0.5 least significant bit (LSB). The proposed CMOS image sensor was designed based on Taiwan Semiconductor Manufacturing Company (TSMC) 0.18-μm CMOS technology and was simulated by CADENCE SPECTRE circuit simulator. This circuit can be proposed for a CMOS imager with highly accurate and efficient power consumption. 相似文献
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In recent years, high‐precision and high‐resolution encoders are expected for nanotechnology control systems. High‐precision angle calibration devices are required and hence, they have been developed according to industry expectations. The accuracy of the disk and angle sensor was calibrated with high precision using the same accuracy measurement system, and a high‐precision angle sensor was achieved. Using the high‐precision angle calibration system, the encoder was realized with a high level of wide accuracy of 0.2 second. In addition, a high‐resolution angle sensor with 30 bits was created, and the multifunctional angle sensor which has acceleration data and bus communications for a servo system was developed. The principle by which an angle sensor calibrates the accuracy by itself has been developed. The base technology for applying an angle sensor to a nanotechnology system was established. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(3): 68–77, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20650 相似文献
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基于0V7620的机器人视觉导航系统设计 总被引:1,自引:0,他引:1
视觉导航技术是移动机器人智能化研究的关键技术。本文介绍了一种基于CMOS图像传感器OV7620的视觉导航系统,通过分析OV7620的工作机理,采用FPGA和FIFO存储器协调工作进行图像采集缓冲,同时利用高速单片机实现视觉导航算法。实验表明本系统设计合理,集成度高,控制精确,有一定的实用价值。 相似文献
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Takashi Ito Yoshiyuki Morishima 《IEEJ Transactions on Electrical and Electronic Engineering》2008,3(3):313-316
This paper presents quantitative evaluation method of corrosive sulfur in insulating oil. The level of corrosion on copper strip which was aged in insulating oil is expressed numerically by the amount of sulfur on it. Since X‐ray strength by wave length dispersive X‐ray (WDX) and measurement value of sulfur on copper strip by titration show good correlation, the amount of sulfur can be obtained rapidly only by WDX. The performance of passivator such as BTA or Irgamet39 was quantitatively evaluated by WDX. The evaluation of life of passivator was also achieved. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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