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Ashok, V., Balakumaran, T., Gowrishankar, C., Vennila, I.L.A. and Kumar, A.N. (2010) The Fast Haar Wavelet Transform for Signal & Image Processing. International Journal of Computer Science and Information Security, 7, 126-130.

has been cited by the following article:

• TITLE: Ultrasonic Rangefinder Spikes Rejection Using Discrete Wavelet Transform: Application to UAV

  AUTHORS: Ayman El-Badawy, Ramy Rashad

  KEYWORDS: Discrete Wavelet Transform, Quadrotor, Ultrasonic, Spikes Rejection

  JOURNAL NAME: Journal of Sensor Technology, Vol.5 No.2, June 2, 2015

  ABSTRACT: This paper presents a spikes removing methodology for ultrasonic rangefinders with an application to a quadrotor unmanned aerial vehicle. Ultrasonic sensors suffer from spikes in distance measurements due to specular reflectance and acoustic noise. Removing these spikes is necessary for improving the hovering performance of the quadrotor. The spikes removing algorithm is based on the discrete wavelet transform. The algorithm is implemented in simulation to study the effect of the altitude measurement spikes on the control performance of the quadrotor with and without the algorithm. The algorithm is also implemented digitally on ultrasonic measurements from a real flight. Results show that the method is capable of rejecting the spikes in the measurements efficiently leaving the altitude control signal unaffected.