Browsing by Subject "Ultrasonic applications"

Now showing 1 - 3 of 3

Open Access
Directional processing of ultrasonic arc maps and its comparison with existing techniques
(IEEE, 2007) Barshan, Billur; Altun, Kerem
Directional maximum (DM) technique for processing ultrasonic arc maps (UAMs) is proposed and compared to existing techniques. It employs directional processing in extracting the map of the environment from UAMs. DM aims at overcoming the intrinsic angular uncertainty of ultrasonic sensors in map building, as well as eliminating noise and cross-talk related misreadings. The comparison is based on experiments with a mobile robot which ac-quired ultrasonic range measurements through wall following. Three complementary performance criteria are used. The DM technique offers a very good compromise between mean absolute error and correct detection rate, with a processing time less than one tenth of a second. It is also superior in range accuracy and in eliminating artifacts, resulting in the best overall performance. The results indicate several trade-offs in the choice of UAM processing techniques.
Open Access
Intelligent controlling microbubble radial oscillations by using Slave-Master Feedback control
(Elsevier Inc., 2014) Behnia, S.; Yahyavi, M.; Mobadersani F.
Dynamics of acoustically driven microbubbles in ultrasonic fields are known to be complex and uncontrollable phenomena indicative of a highly active nonlinear as well as chaotic behavior. In this paper, a method based on Slave-Master Feedback (SMF) to suppress unstable radial oscillations of contrast agents is presented. In the proposed control process, the encapsulated microbubbles as the slave system is coupled with a dynamical system as the master, so that the output of the coupled system is able to produce a stable oscillation. A great virtue of this control technique is its flexibility. In comparison with existing techniques, the present dynamical chaos control method does not need to know more than one variable. The numerical results show its strong impact on reducing the chaotic oscillations to regular ones. © 2014 Elsevier Inc. All rights reserved.
Open Access
Performance evaluation of ultrasonic arc map processing techniques by active snake contours
(2008) Altun, K.; Barshan, B.
Active snake contours are considered for representing the maps of an environment obtained by different ultrasonic arc map (UAM) processing techniques efficiently. The mapping results are compared with the actual map of the room obtained with a very accurate laser system. This technique is a convenient way to represent and compare the map points obtained with different techniques among themselves, as well as with an absolute reference. It is also applicable to map points obtained with other mapping techniques. © 2008 Springer-Verlag Berlin Heidelberg.