According to the principle of centroid measurement, position-sensitive detectors (PSD) are commonly used for micro displacement detection. However, single-beam detection method cannot satisfy such tasks as multi-dimension position measurement, three dimension vision reconstruction, and robot precision positioning, which require synchronous measurement of multiple light beams. Consequently, we designed PSD phase detection method using frequency-domain multiplexing for synchronous detection of multiple modulated light beams. Compared to previous PSD amplitude detection method, the phase detection method using FDM has advantages of simplified measuring system, low cost, high capability of resistance to light interference as well as improved resolution. The feasibility of multi-beam synchronous measurement based on PSD phase detection using FDM was validated by multi-beam measuring experiments. The maximum non-linearity error of the multi-beam synchronous measurement is 6.62%.
According to the drawback of elastic style six-degree-of-freedom (6-DOF) accelerometer, a novel parallel piezoelectric six-degree-of-freedom accelerometer is proposed. First, the operating principle and structure of the accelerometer is presented, then the finite element model of accelerometer is established by ANSYS analysis tools, and getting some parameters, such as output charge sensitivity, resonance frequency etc. Finally, on the basis of analysis of simulation results, a conclusion can be given that cross-axis sensitivity is less than 1%. The resonance frequency is more than 5900Hz, the accelerometer has simple and rational structure and all parameters meet requirement.
The paper proposes a new spatio-temporal gait representation, called cycles gait Zernike moments (CGZM), to
characterize human walking properties for individual recognition. Firstly, Zernike moments as shape descriptors are used
to characterize gait silhouette shape. Secondly, we generate CGZM from Zernike moments of silhouette sequences.
Finally, the phase and magnitude coefficientsof CGZM are utilized to perform classification by the modified Hausdorff
distance (MHD) classifier. Experimental results show that the proposed approach have an encouraging recognition
performance.
This paper describes the design and the calibration of a novel parallel piezoelectric six-axis force/torque sensor. A new
force-sensing cell distribution model has been investigated: eight piezoelectric quartz crystal cells are uniformly
distributed along one circle line to get the spatial force information. The mathematic model of the method has been
deeply researched, established and calculated. In this paper, the negative step response method is calibrated to evaluate
the dynamic response of the sensor: the calibration force acting on the sensor is suddenly removed by breaking a brittle
material. Based on the experimental data of the calibration, the natural frequency, dynamic range as well as coupling
interference of the sensor are analyzed and discussed. The new force-sensing cell distribution model may overcome
some disadvantages of present six-axis force sensor, such as improving the overall stiffness of the sensing system, and
meanwhile, reducing the coupled interference.
Finger-vein recognition uses the finger-vein pattern extracted from the captured vein images to identify individuals. However, the captured vein images contain irregular shading and noise. To extract effective vein pattern from these unclear images, this paper proposes a novel vein pattern extraction approach by running the region growing operator on the different seeds. As the proposed method emphasizes continuity and symmetry of valleys in the cross-sectional profile, it can extract the robust finger-vein patterns and be against irregular shading and noise. Experimental results show that the proposed method achieves robust vein pattern extraction and provides a lower equal error rate in finger-vein recognition.
Position sensitive detector (PSD) is based on the lateral photoelectric effect (LPE) to produce an electrical. The
photocurrents output from the electrodes, so the amplitude and phase of the output signal are related to the distance
between the light spot and the electrodes. The information of the phase was detached from photocurrent signal. The
diversification of phase along with the distance was analyzed, and phase difference between the corresponding electrode
signal current as well as the associated difference with the change of PSD related parameters. The result of experiment
on one-dimensional and two-dimensional PSD is shown that the position detection error and the linearity all can meet the
test requirements.
As a very important part in the robot sensory system, tactile sensing, like hearing and vision, is a particular means by
which the robot acquires information from outside environment. In this paper, the theory model of intelligent robot
tactile sensing costume is demonstrated, and further, according to the piezo-resistive property of conductive rubber the
sensing costume made of tactile array is proposed. In the system, a practical system is designed for signal processing,
data gathering and displaying. Results got from experiments are satisfactory.
It is difficult to on-line measure the large gear''s spiral error based on the coventional method and theory because of some specialities of a large gear. A new system of on-line measuring the large gear'' s spiral error has been studied in this paper. The measuring theory of the system and the system'' s structure have been introduced in this paper. While this new and original method mentioned in this paper has been used the measuring system will be very simple which makes it easy to measure by side.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.