Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Conference Object Citation - Scopus: 1Depth Camera Calibration Using 4 Spheres on Tetrahedron Corners(IEEE, 2022) Tunçer, Esra; Gümüştekin, ŞevketIn this study, a system including 4 depth cameras (Kinect v1) was constructed for 3-dimensional reconstruction of an object. As with all cameras, the calibration parameters of the cameras used must be known in order to transform from image coordinates to world coordinates in depth cameras. Contrary to the studies that use flat calibration objects such as checkerboard and infrared images, which are frequently encountered in the literature, in this study, only depth images of the cameras were used to find intrinsic and extrinsic parameters of a depth camera. For the calibration process, a new tetrahedron calibration object with 4 equiradius spheres was designed, the sphere centers were determined in the world and image coordinates, and the projection matrix method was applied. The minimum number of matching points required by the original projection matrix method was reduced from 6 to 4 with the help of depth information. A new calibration object and method was developed to provide successful 3-dimensional reconstruction results of 4 depth cameras with the use of only 4 matching points and can be used in all types of depth cameras.Conference Object Citation - WoS: 2Citation - Scopus: 5Ardışık Etkinleştirilen Çoklu Derinlik Kameraları Kullanımıyla 3b Nesne Geriçatımı(IEEE, 2020) Tunçer, Esra; Gümüştekin, ŞevketBu çalışmada, bir objenin 3-boyutlu yapısının tümüyle elde edilmesi amacıyla objenin çevresine 4 adet derinlik kamerası (Kinect v1) yerleştirilmiştir. Çoklu Kinect kullanımında karşılaşılan bilgisayar bant genişliği ve girişim problemleri eklenti USB 2.0 kontrolcüler ve elektronik kontrollü objektif kapakları ile çözülmüştür. Alınan görüntülerin birleştirilmesi için kalibrasyon işlemi kızılötesi görüntüler üzerinde uygulanmıştır. Eşleşme problemleri Döngülü En Yakın Nokta metoduyla giderilmiş ve %3.41 hata oranına sahip eşleşme elde edilmiştir. Farklı geometrik özelliklere sahip nesnelerin 3B modellenmesi için eşleştirilen nokta bulutlarına Meshlab yazılımı aracılığıyla Poisson Yüzey Geriçatımı işlemi uygulanmıştırConference Object Citation - Scopus: 3Sahne Aydınlatmasında Kullanılan Işık Kaynağının Renklilik Değerlerinin Tek İmge Kullanılarak Kestirimi(IEEE, 2011) Ozan, Şükrü; Gümüştekin, ŞevketIn this study, main goal is to estimate scene illuminant chromaticity values for each of the three color channels (red, green, blue). It is found that analysis of the pixel values, which are expressed by dichromatic reflection and inverse-intensity chromaticity space definitions, with appropriate statistical methods gives aproximate values for light source chromaticity within an acceptable error range. Single image of a scene is sufficient for calculations. We saw that chromaticity values of light sources with different colors can be approximately calculated. © 2011 IEEE.Conference Object Ölçülmüş Çydf Verilerinin Lafortune Modeli ile Etkin Gösterimi(IEEE, 2010) Ozan, Şükrü; Gümüştekin, ŞevketThe bi-directional reflectance distribution function (BRDF) describes the appearance of a material by its interaction with light. In this study, Lafortune BRDF model is fitted to densely sampled measured BRDF data by using Levenberg - Marquardt Algorithm. The obtained results are visualised by a physically based ray tracing software and the proposed method is analysed. ©2010 IEEE.