Köksal, Kerem | Surucu, Dilek | Surucu, Murat | Hacıoğlu, Rıfat

| 2014 | 2014 22ND SIGNAL PROCESSING AND COMMUNICATIONS APPLICATIONS CONFERENCE (SIU) , pp.646 - 649

In this study, it is aimed to follow a visual route by an Unmanned Aerial Vehicle (UAV). The recognition of the predetermined line by using image processing algorithms and the process of following the route by using the method of Tangent Vector Field Guidance (TVFG) have been performed in indoor and outdoor experiments. UAV's following the correct route has been ensured by calculating the deflection caused by some factors such as wind and light which adversely affect the flight of UAV. In Vector Field Guidance method, the direction angles calculated by using the vector fields that will follow the line-shaped guide path are used. Whe . . .n the path to be followed has more than one direction instead of a single straight line, it is divided into sections which consist of straight lines, and by prioritizing these lines, the most dominant line is followed. In this study, it is aimed to provide a dynamic model by considering the tracking errors. As a result of the process adopted, UAV's autonomous flight is achieved by using the visual inputs and TVFG method, and the external disturbing factors are investigated Daha fazlası Daha az

Altan, Aytaç | Bayraktar, Köksal | Hacıoğlu, Rıfat

| 2016 | 2016 24th Signal Processing and Communication Application Conference, SIU 2016 - Proceedings , pp.1433 - 1436

In this stuidy, the position information from ultrasound sensors on UAV related to floor gallery mine passed through the filter, it is aimed to control the position of simultaneously creating the optimum environmental map. The simultaneous in galleries made mapping, mine the data of air to the designated central monitoring system with real-time location information is transmitted to the ventilation system, which is intended to more effectively work in the mines. The gallery maps which simultaneous location and mapping information obtained by UAV Extended Kalman Filter algorithms processed were obtained experimentally. © 2016 IEEE.

Karasu, Seçkin | Altan, Aytaç | Saraç, Zehra | Hacıoğlu, Rıfat

| 2017 | 2017 25th Signal Processing and Communications Applications Conference, SIU 2017 , pp.1433 - 1436

In this study, the wind speed prediction model is created that gives a minimum error for different hidden layer neuron numbers and delay step numbers. Using the one-minute time series, the prediction of the next wind speed is performed with the NAR neural network model. The predicted values of wind speed obtained are compared with predicted values of wind speed obtained with filter methods. For different window functions and lengths, wind speed prediction is made using filters with different weight coefficients. For the number of hidden layer neurons is 14 and the number of delay steps is 10, MAE, MSE and RMSE values are calculated . . .as 0.0315, 0.0019, 0.0445, respectively, with NAR neural network. It is seen that the proposed method for the wind speed dataset has a higher prediction performance than thefilter methods. © 2017 IEEE Daha fazlası Daha az

Onur, Tuğba Özge | Hacıoğlu, Rıfat

| 2017 | 2017 25th Signal Processing and Communications Applications Conference, SIU 2017 , pp.1433 - 1436

Reverberation and multipath propagation afîect the accuracy of time of flight (TOF) estimation in confined underwater medium. In this paper, time delay has been estimated by obtaining the transmitted signal and first echo signal from measured signal acquised by using a wideband transducer with 5 MHz central frequency. Cross-correlation (CC) and generalized cross-correlation (GCC) methods have been applied to the obtained signals and their performances have been compared. The results show that GCC method has better performance for time delay estimation in confined underwater medium where multipath propagation and reverberation are se . . .vere. © 2017 IEEE Daha fazlası Daha az

Onur, Tuğba Özge | Hacıoğlu, Rıfat

| 2016 | 2016 24th Signal Processing and Communication Application Conference, SIU 2016 - Proceedings , pp.821 - 824

In this paper, two different methods are suggested in order to provide image enhancement in ultrasonic B-mode imaging. By obtaining RF data from two different phantom used to form B-mode image, their spectral characteristics were observed. Then by forming RF envelope from obtained data, conversion of envelope to color image is provided. Logarithmic compression and histogram equalization methods found in literature are used to improve image quality. From the results obtained, it is observed that both algorithms are effective based on the intended use when they are applied individually. © 2016 IEEE.

Altan, Aytaç | Köksal, Kerem | Hacıoğlu, Rıfat

| 2017 | Karaelmas Fen ve Mühendislik Dergisi7 ( 1 ) , pp.218 - 227

Bu çalışmada, görsel çizgi (rota) takibi için İnsansız Hava Aracı (İHA) üzerinde bulunan 3 eksenli yalpanın dış bozucu etki altında model öngörülü denetimi gerçekleştirilmektedir. İHA ile görsel çizgi takibi için Tanjant Vektör Alan Kılavuz (TVAK) yöntemi kullanılmaktadır. Dış ortam ve kapalı ortamda yapılan testlerde, ön tanımlaması yapılan çizginin görüntü işleme algoritmalarıyla tespiti ve sonrasında TVAK yöntemi kullanılarak rota takip işlemi gerçekleştirilmektedir. İHA’nın alçak ve yüksek irtifa uçuşlarında rota takibi başarım oranları deneysel olarak gözlemlenmektedir. Elde edilen sonuçlar PID denetime sahip yalpadan elde edil . . .en veriler ile karşılaştırılmaktadır. Dış bozucu etki altında TVAK yöntemi ile rota takibi için İHA üzerindeki 3 eksenli yalpanın MPC denetiminde PID ile denetime göre başarılı sonuçlar elde edilmektedir. In this study, Model Predictive Control (MPC) is performed under the external disturbance effect of the 3-axis gimbal on the Unmanned Aerial Vehicle (UAV) for visual line tracking. The Tangent Vector Fields Guide (TVFG) method is used for visual line tracking with UAV. In the tests performed in the outdoor and indoor environments, the pre-defined line is detected with the image processing algorithms and then the line tracking process is performed using the TVFG method. The visual line tracking success rates in the low and high altitude of UAV flight are observed experimentally. The obtained results are compared with data obtained by the gimbal having PID control. The successful results are obtained with MPC control according to PID control of 3 axis gimbal on UAV under external disturbance for visual line tracking using TVFG method Daha fazlası Daha az

Onur, Tuğba Özge | Carlson, Johan E. | Svanström, Erika | Hacıoğlu, Rıfat

| 2017 | Erzincan Üniversitesi Fen Bilimleri Enstitüsü Dergisi10 ( 1 ) , pp.138 - 147

Elastik dalgalar, sadece gaz ve sıvılarda değil aynı zamanda katılarda da yayılırlar. Katılar, sıvı ve gazlarda olmayan form elastisitesine sahip olduğundan, katıların elastik özellikleri farklıdır. Bu nedenle, sadece boylamsal dalgalar değil aynı zamanda diğer dalgalar da katılarda yayılabilir. Katı içinde yayılan dalgalar kullanılarak hedefin konumu hakkında bilgi edinilebilir. Bu çalışmada ince düzlemlerde tek transdüktör kullanılarak ultrasonik dalga yayılımının modellenmesi yapılarak, uyarlamalı algoritma ile hedef uzaklığı kestirilmektedir. Elde edilen sonuçlarda, modellenen dalga yayılımında ultrasonik dalganın hızı ile birli . . .kte zaman gecikmesi uyartım noktasının sensöre olan uzaklığı ile ilintili olduğu için, uyarlamalı algoritma ile darbe cevabı başlangıç noktası belirlenerek hedef konumunun tespit edilebildiği görülmektedir. Elastic waves propagate not only in gases and liquids but also in solids. The elastic properties of solids are different since they have form elasticity which liquids and gases don't have. Because of this reason, not only longitudinal waves but also other waves can propagate in solids. Waves propagating in solids can be used to get information about target location. In this paper, modelling of ultrasonic wave propagation in thin plates is investigated by using a single transducer and target distance is estimated with adaptive algorithm. According to the obtained results, it can be seen that target location can be estimated by detecting the starting point of the impulse response with adaptive algorithm since the delay along with the velocity of ultrasound wave in the modelled wave propagation is related to the distance between the excitation point and sensor Daha fazlası Daha az

Onur, Tuğba Özge | Carlson, Johan E | Svanström, Erika | Hacıoğlu, Rıfat

| 2019 | Iranian Journal of Science and Technology - Transactions of Electrical Engineering43 ( 3 ) , pp.405 - 413

This paper demonstrates how flexural wave propagation in a thin plate can be modeled by estimating the combined effect of the excitation source signal and the impulse response of the ultrasonic sensor. The wave propagation in the plate is modeled using the wave equation for the flexural wave mode. A theoretical model for flexural wave propagation in thin plates has been derived, and it has been compared with measurements excited by tapping gently on the surface. The combined effects of the excitation source signal and the impulse response of the low-cost piezoelectric sensor are modeled using finite-impulse response and/or infinite- . . .impulse response filters. Thereafter, the performances of the selected filters are compared on estimating the wave propagation in a thin quartz glass plate. Results indicate that the most accurate estimation of wave propagation has been obtained using a linear phase filter which attributes all dispersions to the flexural wave. © 2018, Shiraz University Daha fazlası Daha az

Surucu, Dilek | Surucu, Murat | Koksal, Kerem | Hacıoğlu, Rıfat

| 2015 | 2015 23rd Signal Processing and Communications Applications Conference, SIU 2015 - Proceedings , pp.1849 - 1852

In this study, we perform target detection and tracking with Unmanned Aerial Vehicle (UAV) as well as the visual command of UAV. Our goal is to develop an autopilot system to reduce the human factor in UAV's. We create a system that follows different objects, stays locked to a graphical object which is glyph that has an encryption that only we describe, and executes the mission encoded on glyph in both indoor and outdoor tests. We obtain the targeting by the angle and the dimensions of the glyph. We've obtained successful results in applied presentations. © 2015 IEEE.

Onur, Tuğba Özge | Hacıoğlu, Rıfat

| 2017 | Turkish Journal of Electrical Engineering and Computer Sciences25 ( 2 ) , pp.939 - 949

We investigated adaptive algorithms for a Hammerstein block structure in which a static nonlinear block and dynamic linear block are cascaded. The approach considered here is to use generalized orthonormal basis functions in a Hammerstein block structure by using xed pole lter banks. We applied the normalized least mean square approach to the developed adaptive algorithm in order to acquire Hammerstein block structure parameters. Performance comparison of the proposed approach was investigated considering convergence speed and parametric complexity for acoustic echo cancellation application. The results indicated that in the develop . . .ed algorithm along with appropriate selection of xed poles, the algorithm convergences faster and less parametric complexity is provided when compared to direct adaptive Hammerstein algorithms with IIR and FIR linear blocks. We investigated adaptive algorithms for a Hammerstein block structure in which a static nonlinear block and dynamic linear block are cascaded. The approach considered here is to use generalized orthonormal basis functions in a Hammerstein block structure by using xed pole lter banks. We applied the normalized least mean square approach to the developed adaptive algorithm in order to acquire Hammerstein block structure parameters. Performance comparison of the proposed approach was investigated considering convergence speed and parametric complexity for acoustic echo cancellation application. The results indicated that in the developed algorithm along with appropriate selection of xed poles, the algorithm convergences faster and less parametric complexity is provided when compared to direct adaptive Hammerstein algorithms with IIR and FIR linear blocks Daha fazlası Daha az

Özdinç, Tuğba Özge | Hacıoğlu, Rıfat

| 2007 | 2007 IEEE 15TH SIGNAL PROCESSING AND COMMUNICATIONS APPLICATIONS, VOLS 1-3 , pp.939 - 949

Acoustic echo in voice transmission systems severely degrades the speech quality and the speech intelligibility of speech signal due to it is formed through picking up sounds from the loudspeaker by speaker microphone. The dynamic strucure of the acoustic echo system contains cascade connection of an electro-acoustic static nonlinear system and a dynamic linear system. Hence linear models can not be successful solution to echo problem. In this paper, acoustic echo problem is mentioned and an algorithm that adapts the parameters of nonlinear Hammerstein system (cascade connection of a static nonlinearity and a dynamic linear system) . . .is suggested Daha fazlası Daha az

Onur, Tuğba Özge | Hacıoğlu, Rıfat

| 2013 | 2013 21ST SIGNAL PROCESSING AND COMMUNICATIONS APPLICATIONS CONFERENCE (SIU) , pp.939 - 949

The speech signals are formed with echo caused by the reflections and also noise caused by engine, tyres, wind, etc during using hands-free voice communication in automobiles. In this paper, it has been focused on the adaptive filtering algorithms that based on eliminating purpose of not only noise removal but also separation in speech signals with echo and noise. It has been evaluated that the speech signals separation performance by comparing adaptive filtering methods that made with Least Mean Squares (LMS) and Recursive Least Squares (RLS) algorithms. Signals belong to near and far end speakers will be decomposed with each while . . . near-end and far-end speakers' signals affected by noise are decomposing from noise with the proposed adaptive algorithms. Furthermore, convergency and error analyses are performed by comparing the performances of LMS and RLS algorithms Daha fazlası Daha az