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GÜRKAN, GÜRAY

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Dr. Öğr. Üyesi

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Now showing 1 - 10 of 21
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    PublicationEmbargo
    Texture Analysis Based Iris Recognition
    (2006-01) Akan, Aydın; GÜRKAN, GÜRAY; 113297; 2918
    In this paper, we present a new method for personal identification, based on iris patterns. The method composed of iris image acquisition, image preprocessing, feature extraction and finally decision stages. Normalized iris images are vertically log-sampled and filtered by circular symmetric Gabor filters. The output of filters are windowed and mean absolute deviation of pixels in the window are calculated as the feature vectors. The proposed method has the desired properties of an iris recognition system such as scale and rotation invariance. The system is realized in Windows platform using Delphi compiler.
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    PublicationOpen Access
    Incu-Stream 1.0: An Open-Hardware Live-Cell Imaging System Based on Inverted Bright-Field Microscopy and Automated Mechanical Scanning for Real-Time and Long-Term Imaging of Microplates in Incubator
    (2019) Gürkan, Koray; GÜRKAN, GÜRAY
    Microplate (i.e. microwell plate) is a flat plate that has a specific number of wells to be used as small test tubes in cell-culture studies. In most of the low-budget mammalian cell study laboratories, highly skilled laboratory personnel should determine microscopic changes in microplate well media by taking the microplate outside the incubator and by imaging each well medium under a microscope, with the risk of contamination and reliability degrading. An alternative solution is to use an in-incubator operated live-cell imaging device, which, however, cannot be afforded by low-cost laboratories. In this paper, we present the design, realization, and test stages of a microplate compatible inverted bright-field microscope system that can be used in incubators. The developed system enables real-time and long-term in-incubator imaging of any user-selectable microplate type. The device can capture bright-field microscopic images by using a low-cost CMOS image sensor, an inverted varifocal CCTV lens and an array of light emitting diodes. In addition, by developed two-axial movement stage and image augmenting algorithms, the whole area of a user selectable well (e.g. area of a 6.5 mm diameter well in a 96-well plate) can be automatically imaged without using any other third party software. The long-term performance of the system is tested in incubators with human embryonic kidney and breast cancer cell lines.
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    PublicationMetadata only
    An Arduino UNO application: GPS guided unmanned ground vehicle
    (IEEE, 345 E 47Th St, New York, Ny 10017 USA, 2017) Bozik, Tugay; GÜRKAN, GÜRAY; 113297
    This paper presents an application of Arduino UNO to GPS guided unmanned vehicle. The four-wheeled small scale (55 cm x 25 cm) vehicle is capable of moving forward, rotating and consists of a GPS sensor, a magnetometer, a motor driver and four DC motors. The target coordinates (key points) are manually entered as a part of the control algorithm script (.ino file). The developed control algorithm makes a blind calculation of the distance and required rotation between consecutive key points. The initial coordinates of the vehicle, however, requires the only field-dependent calculation of the distance and target heading between the initial and the first key point. The whole target route is achieved by consecutive "rotation" and "forward movements (straight path)" between key points. The GPS sensor is used to determine the initial coordinates whereas magnetometer is used to determine the heading (and rotation) before (and during) each key point movement. When taxiing through blind-calculated route, the acquired GPS data is transmitted via Bluetooth for offline monitoring.
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    Design and realization of multi-channel wireless data acquisition system for laboratory-scale experiments on structural health monitoring
    (Jve Int Ltd, Geliu Ratas 15 A, Kaunas, Lt-50282, Lithuania, 2018-03) Gürkan, Koray; Dindar, Ahmet Anıl; GÜRKAN, GÜRAY; 101880; 113297; 29079
    In this paper, we present the design steps of a low cost multi-channel accelerometer system accompanied with an open-source data acquisition software. Hardware part of the system, named KACC, is composed of battery powered tri-axial MEMS accelerometers that use IEEE 802.15.1 protocol for data transmission. The software part, named PyKACC, is developed under Python (c) open-source environment and handles initiation of data acquisition, data synchronization and data logging. The developed system is tested for synchronization and reliability via shake-table tests and results are presented.
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    PublicationMetadata only
    Doku Analiz Yaklaşımına Dayanan Yeni Bir İris Tanıma Yöntemi
    (IEEE, 2005) Akan, Aydın; GÜRKAN, GÜRAY; 113297; 2918
    Bu çalışmada, iris yardımı ile kişi tanıma konusunda doku analizine dayalı yeni bir yöntem sunulmaktadır. İris görüntüleri bir ön işlemeden geçirildikten sonra doku analizine dayanan öznitelik vektörleri çıkarılmaktadır. Normalize edilen iris görüntüsü dikey logaritmik olarak örneklenir ve dairesel simetrik Gabor süzgeçlerinden geçirilir. Süzgeç çıkışları üzerinde kayan bir pencere altındaki piksellerin ortalama mutlak sapma değerleri öznitelik olarak elde edilir. Önerilen yöntem, iris ile kişi tanıma sisteminde aranan önemli niteliklerden ölçek ve dönüş ile değişmezlik özelliklerine sahiptir. Sistemin yazılım kısmı, Delphi derleyicisi ile Windows ortamında gerçeklenmiştir.
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    PublicationRestricted
    An Open-Source User Interface Development for Widely Used Low-cost Spectrometer Designs
    (Istanbul Univ., 2020) GÜRKAN, GÜRAY
    In this paper, the development and test stages of an open-source user interface are presented. The developed user interface is compatible with most of the low-cost camera-based spectrometer designs in the literature. The spectrum image of the light source that is acquired with the camera is cropped and analyzed in a real-time thread after interactive calibration which is a special feature of the user interface. Camera controls (such as brightness, contrast, saturation, exposure and etc.) are also available through the user interface. For user interface testing, a common spectrometer design that is composed of a light-guide tube with a narrow entrance slit in one end and an image sensor on the other is constructed. Various compact fluorescent lamps and light emitting diodes are applied as light source and the results are presented. Developed cross-platform user interface can be used with lowcost spectrometer designs especially involving a web camera.
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    Application of Stockwell Coherence To Prediction Of Alertness Under Anaesthesia
    (Brno Univ Technology Vut Press, Purkynova 118, Brno 61200, Czech Republic, 2010) Akan, Aydın; Demiralp, Tamer; GÜRKAN, GÜRAY; TR113297; TR2918; TR6916
    In this paper, we represent an application of Stockwell Coherence to scalp EEG signals under anesthesia. By the analysis of overlapping, stationary data segments, we obtained the time-varying Stockwell coherence, which reveals the time evolution of coherence changes between any selected channel pair. After the injection and release of the anesthetic agent, time-varying Stockwell coherence analyses demonstrate similar characteristics for different patients.
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    EEG Sinyalinin Anestezi Sırasındaki Topografik ve Zamansal İzge Analizi
    (IEEE, 2018) Uslu, Atilla; Cebeci, Bora; Erdoğan, Ezgi T.; Kaşıkçı, Itır; Seyhan, Tülay Ö.; Akan, Aydın; Demiralp, Tamer; GÜRKAN, GÜRAY; 113297; 221283; 141798; 167802; 2918; 6916
    Bu çalışmada EEG sinyalinin anestezi altındaki izgesel değişimi, zamansal ve uzaysal olarak incelenmiştir. Bu amaçla kullanılan yöntemler arasında, günümüz anestezi derinliği takip cihazlarının da kullandığı bilinen SEF-90, α-β bandı güç oranları ve izgesel entropi yer almaktadır. Ayrıca doğrusal olmayan sistemlerin analizinde kullanılan Higuchi fraktal boyutu da karşılaştırma olarak incelenmiştir. Uzaysal analiz sonucunda, normal bireylerde oksipital bölgede görülen baskın alfa aktivitesinin artan anestezi derinliği ile frontal bölgeye kaydığı doğrulanmış ve ilgili topografik gösterimler sunulmuştur.
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    PublicationRestricted
    Design and Realization of an Automatic Optical Inspection System for PCB Solder Joints
    (Institute of Electrical and Electronics Engineers Inc., 2021) ÇALIŞKAN, AYHAN; GÜRKAN, GÜRAY
    Recent developments in electronics has led to an increase in fabrication and assembly speeds of printed circuit boards (PCBs). In addition, the size of manufactured PCBs and electronic components (e.g. resistors, capacitors, transistors etc.) are becoming much smaller. By increased demand and production speed, the reliability and thus the inspection of manufactured PCB assemblies became an important issue. In the assembly PCB production process, detection of surface mount technology (SMT) solder defects is made with automatic optical inspection (AOI) devices using image processing methods. Besides these expensive device methods, the method by which the controls are made by the operators visually is a low-cost solution used by most of the companies that manufacture printed circuit board assembly. In addition, circuit defects and solder defects cannot be tested and controlled with 100% accuracy due to human error. This paper proposes to detect solder joint defects with machine learning methods using YOLO algorithm to speed up time and increase accuracy in assembly PCB production line. Approximately 40000 images were obtained from the real production line before training with the YOLOv4 algorithm for high accuracy rate. Detection of solder defects of SMT circuit elements in approximately 5K (4056x3040) images resolution can be achieved with 97% accuracy in around 4 seconds. As a result of the use of the system, this proposed method has been proven with the reports received from the production line and precision-recall curves. Thus, it has been observed that the production speed and accuracy rate are increased. © 2021 IEEE.
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    PublicationRestricted
    PyTHang: an Open-s-Source Wearable Sensor System for Real-Time Monitoring of Head-Torso Angle for Ambulatory Application
    (Taylor & Francis Ltd., 2021) GÜRKAN, GÜRAY
    This article presents the realization of a low-cost wearable sensor system and its Python-based software that can measure and record relative head-torso angle, especially in sagittal plane. The system is mainly developed to track head-torso angle during walk in a clinical study. The open-hardware part of the system is composed of a pair of triaxial digital accelerometers, a microprocessor, a Bluetooth module and a rechargeable battery unit. The reception of the transmitted acceleration data, visualization, interactive sensor alignment, angle estimation and data-logging are realized by the developed open-source graphical user interface. The system is tested on a tripod for verification and on a subject for practical demonstration. Developed system can be constructed and used for ambulatory monitoring and analysis of relative head-torso angle. Open-source user interface can be downloaded and developed for further (different) algorithms and device hardware.