机构

• 长春光学精密机械与物... [2]
• 生物物理研究所 [1]

采集方式

• OAI收割 [3]

内容类型

• 会议论文 [2]
• 期刊论文 [1]

发表日期

• 2010 [1]
• 2009 [1]
• 2005 [1]

学科主题

• Radiology,... [1]

筛选

浏览/检索结果: 共3条，第1-3条 帮助 条数/页： 5101520253035404550556065707580859095100 排序方式： 请选择题名升序题名降序提交时间升序提交时间降序作者升序作者降序发表日期升序发表日期降序 New phase measurement method for laser rangefinder (EI CONFERENCE) 会议论文  OAI收割 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China 作者:  Meng Z.;  Meng Z. 收藏  |  浏览/下载：27/0  |  提交时间：2013/03/25 A new phase measurement method is designed and presented by using the technique of signal shifting phase and the technique of signal multiplication for laser rangefinder. The intensity of laser light is modulated by cosine circuit signal  at the same time the cosine circuit signal is thansformed sine signal by the shifting phase technique. Two signals mentioned above are multiplied by received signal from the target respectively  then being transmitted into signal processor after passing through low band filter respectively. The result of phase-shift between the received signal and sent signal is calculated by means of signal processor and time-counter with double frequency of modulation signal. The proposed system is composed of four units such as control and count unit  emitting and receiving unit of laser light  signal processing unit and result display unit. The two most advantages of proposed system over others are its ability of proper isolation which reduces crosstalk and its independency thermal drift. Theoretical calculations and experimental results have shown the accuracy better than 2 mm. 2010 Copyright SPIE - The International Society for Optical Engineering.   Physiological Origin of Low-Frequency Drift in Blood Oxygen Level Dependent (BOLD) Functional Magnetic Resonance Imaging (fMRI) 期刊论文  OAI收割 MAGNETIC RESONANCE IN MEDICINE, 2009, 卷号: 61, 期号: 4, 页码: 819-827 Yan, Lirong; zhuo, yan; 卓彦; Ye, Yongquan; Xie, Sharon X; An, Jing; Aguirre, Geoffrey K; Wang, Jiongjiong 收藏  |  浏览/下载：35/0  |  提交时间：2013/12/25 low-frequency drift  physiological noise  blood oxygen level dependent  BOLD  functional magnetic resonance imaging  fMRI   Error analysis and test study of fiber optic gyroscope north-finder (EI CONFERENCE) 会议论文  OAI收割 Advanced Sensor Systems and Applications II, November 8, 2004 - November 12, 2004, Beijing, China Zhang Z.; Sun J.; Wu K. 收藏  |  浏览/下载：22/0  |  提交时间：2013/03/25 North-finder system is an important application of the inertial technology. It provides true north azimuth information to f all kinds of ground-based equipment. This paper designed a dynamic automatic north-finder based on the modulation output of fiber optic gyroscope (FOG). In this scheme  the sine output signal of the FOG was sampled and disposed  and then the real north of surveyed point on the surface of earth was calculated. The deviation caused by the base tilt was compensated by an accelerator. The output signals of FOG and accelerator were computed combined with the position sampled from increasing encoder by digital signal processor. Successive rotating technique was adopted to modulate the FOG signal periodically. Most of the low frequency part of random gyro drift errors was compensated. The north-finder accuracy was improved compared with the traditional static measuring method. The test result shows the FOG automatic north-finder obtains 2' true north angle accuracies within not more than three minutes  can meet the orientation need of artillery  terrain measurement vehicle  armored car  unmanned drive vehicle  geodetic survey and tunnel exploration.