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Günümüzde animasyonun ve dijital efektlerin büyük ilerlemeler kaydettiği görülmektedir. 3d ve 4d modelleme ve grafik tabanlı programların bu süreçte görsel katkısı önemli bir parçasını oluşturmaktadır. Filmlerde kullanılan teknik donanımlar çekim kalitesini ve etkisini değiştirmiştir. Gerçekliğini sorgulamadığımız bir dünyaya ulaştığımız derin ve etkili bir dil kullanıldığı gözlemlenmektedir. İnsanoğlunun geçmişten bugüne görsel zekası ve birikimine uygun, animasyon ve efekt kullanma ve tekniğimizin, teknoloji ile bir bütün şekilde ilerlediğini görmek ve gerçeği yansıtmak artık yeni sonuçlar doğurduğunu göstermek mümkün hale gelmiştir., Animation and digital effects are seem to be making great progress nowadays. The visual contribution of 3d and 4d modeling and graphic based programs is an important part of this progress. The technical equipment used in movies has changed the shooting quality and effect. It is observed that a deep and effective language is used in which we reach a world where we cannot question its realism. It has now become possible to see that our use of animation and effects, which is compatible with the visual intelligence and accumulation of human beings from past to present, is progressing in a whole way with technology, reflecting the reality and producing new results.

20th Signal Processing and Communications Applications Conference, SIU 2012; Fethiye, Mugla; Turkey; 18 April 2012 through 20 April 2012, 3B lazer tarayıcılar yüzey geometrisinin yakalanması için yaygın olarak kullanılan sistemlerdir. Geleneksel lazer tarayıcı sistemler bir adet lazer ışık kaynağına sahiptir. Bu çalışmada iki adet lazer ışık kaynağına sahip bir 3B lazer tarayıcı ele alınmıştır. Bu tarayıcı özellikle sahnelerdeki örtme etkisinin en küçüklenebilmesini sağlamaktadır. Ancak birden fazla lazer kaynağına sahip lazer tarayıcılar için kalibrasyon önemli bir problem olmaktadır. Çalışmamızda bu sistemlerde karşılaşılan kalibrasyon problemi tanımlanmıştır. Bu problemin çözümü için taranan sahnelerdeki dikgenlik, eş-düzlemsellik bilgileri kullanılmıştır., 3D laser scanners are widely used systems to capture surface geometry. Conventional laser scanners have one laser source. In this study, a laser scanner systems with two laser sources is considered. The scanner is capable of minimizing the effect of occlusion in the scene. But the calibration issue becomes more complicated for scanners having more than one laser source. In our study the calibration problem of such scanners are defined. Some scene specific informations like orthogonalities, co-planarities are used for solving this problem. © 2012 IEEE.

Date of Conference: 22-24 April 2010 One of the important techniques used for three dimensional television (3DTV) is holography. In holographic 3DTV, spatial light modulators (SLM) are used as the display device. SLMs that provide the most limited modulation are the binary SLMs, since only two different values can be assigned to their pixels. An important signal processing problem arising here is the determination of the binary signal to be written on the SLM among the possible ones such that the desired light field is generated to the best extent. Many of the proposed methods do not produce satisfactory results in terms of error rate, computational performance or light efficiency. We propose an optical setup to be placed in front of the binary SLM and the associated signal processing algorithm. The proposed system uses a 4-f setup and a periodic mask is placed to the Fourier plane. As a result, the binary SLM is convolved with a series of regularly spaced impulse functions and we get a new SLM which is smaller in pixel count compared to binary SLM but which can provide 16-bit full complex modulation. It becomes easier to generate the desired light field with this new SLM. Also, the required computations are carried out in a fast manner to enable real-time operation. ©2010 IEEE.

Date of Conference: 22-24 April 2010 As computer generated holograms becomes more common, the fast computation of holographic interference patterns in digital environment becomes a necessity. Since the computation time of holograms via Fresnel (or Rayleigh-Sommerfeld) diffraction models makes real time applications impossible, the holographic stereograms are developed to be a solution for this problem. Holographic stereograms divide the hologram plane into segments. In phase added stereograms the coordinates of 3D source points are used while calculating the diffraction field. And that enables to calculate the diffraction field with appropriate sized FFTs. Although the phase added stereograms are advantageous in terms of computation time, the quality of the reconstructed three dimensional images may not be satisfactory. The main reason is that the diffraction field of a given point source is approximated as a pure complex sinusuoid in each segment. To increase the reconstruction quality, we propose a method that uses variable sized segments, as opposed to previously developed holographic stereograms that use fixed sized segments. While approximating the diffraction field of a point source, higher frequency regions are covered with smaller segments and lower frequency regions with larger segments. As a result of this, we keep the total number of oscillations of pure sinusoidal waves constant in each segment. The simulations that we carried out for a point source show that we are able to obtain better quality reconstruction with our method. ©2010 IEEE.

Date of Conference: 9-11 April 2009 Conference name: IEEE 17th Signal Processing and Communications Applications Conference, SIU 2009 In pharmacological experiments behavior pattern of laboratory mice, which are under the influence of psychotherapeutic drugs, reveals important clues about effects of the drug. Behavior analysis of laboratory mice by video processing saves both time and labor. In this work a method which was previously used to recognize human behaviors is adapted to laboratory mice case. Method is based on fitting histograms of spatio-temporal gradients extracted from 3D space-time volumes to multidimensional statistical distributions and class(lj'ing according to distances between the distributions. In this work the method is tested on a common mice video dataset, compared to other methods in the literature and found to be successful. ©2009 IEEE.

Date of Conference: 9-11 April 2009 Conference Name: IEEE 17th Signal Processing and Communications Applications Conference, SIU 2009 In the last few years, there is great increase in capture and representation of real 3-Dimensonal scenes using 3D animation models. The 3D signals are then compressed, transmitted to the client side and reconstructed for the user view. Each step mentioned here opened a new subject in the field of signal processing. While processing these models, using the model as a whole is not the best approach. Therefore clustering the model vertices became a very common method. For example, it is very common to use motion based clustering in animation compression. In this paper a new dynamic model clustering algorithm is proposed. Animation vertices are first put through PCA and partitioned into their eigenvalues and eigenvectors. The eigenvectors found using the proposed method can be called eigentrajectories. Then the dot product of the these eigentrajectories with the trajectories of the animation vertice are found. These coefficients are used to cluster the animation model. The results and the comparisons with a similar approach show that the proposed algorithm is successful.

Date of Conference: 11-13 June 2007 Conference name: IEEE 15th Signal Processing and Communications Applications, 2007 Dikdörtgensel olmayan dalgacık dönüşümüne dayalı çok çözünürlüklü üç boyutlu model sıkıştırılması için iki yöntem önerilmektedir. Bunlar Sıradüzensel Ağaç Yapılarının Kümelere Bölütlenmesi (Set Partitioning In Hierarchical Trees - SPIHT) ve JPEG2000 tekniklerine dayanmaktadır. Üç boyutlu modeller düzenli ızgara yapılar üzerinde tanımlı iki boyutlu imgelere dönüştürülmekte, ve bu gösterim bağlanırlıkla yönlendirilmiş uyarlamalı dalgacık dönüşümünden geçirilerek ortaya çıkan dalgacık kümesi verisi SPITH veya JPEG2000 yöntemlerinden biri uygulanarak bit dizgisine dönüştürülmektedir. SPIHT ile elde edilen bit dizgisinin değişik uzunluklardaki bölümlerinden modelin değişik çözünürlüklerde geri çatmak mümkün olduğundan önerilen bu yöntem modellerin aşamalı gösterimine olanak sağlamaktadır. Dalgacık dönüşümü verilerinin SPIHT ile kodlanmasıyla elde edilen sonuç JPEG2000 ve MPEG-3DGC ile yapılan kodlamanın sonucundan daha başarılı olmuştur. Two compression frameworks that are based on a Set Partitioning In Hierarchical Trees (SPIHT) and JPEG2000 methods are proposed. The 3D mesh is first transformed to 2D images on a regular grid structure. Then, this image-like representation is wavelet transformed employing an adaptive predictor that takes advantage of the connectivity information of mesh vertices. Then SPIHT or JPEG2000 is applied on the wavelet domain data. The SPIHT based method is progressive because the resolution of the reconstructed mesh can be changed by varying the length of the one-dimensional data stream created by SPIHT algorithm. The results of the SPIHT based algorith is observed to be superior to JPEG200 based mesh coder and MPEG-3DGC in rate-distortion.

IEEE;TUBITAK;Istanbul Teknik Universitesi;aselsan;Profilo Telr@ Proceedings of the IEEE 12th Signal Processing and Communications Applications Conference, SIU 2004 -- 28 April 2004 through 30 April 2004 -- Kusadasi -- 64722 Tıbbi ultrasonik görüntüleme sistemleri, genel olarak bir çevirici elemanı ve akustik işaretin üretilip algılanmasından sorumlu elektronik oluşmaktadır. Tek boyutlu dönüştürücü dizileriyle, incelenmekte olan ortamın iki boyutlu kesit görüntüsü elde edilmektedir. Dönüştürücü teknolojisindeki son gelişmelerle, iki boyutlu dönüştürücü dizilerinin üretimi gerçekleştirilmiş, böylece üç boyutlu (hacimsel) görüntüleme yapılması mümkün olmuştur[1,2]. Ancak, özellikle Nyquist kriteri, dönüştürücü elemanların boyutlarını sınırladığı için, eleman boyutları oldukça küçülmüştür; bu da algılanan işareti oldukça zayıflatmaktadır. Bu nedenle, kabul edilebilir nitelikteki görüntülerin alınabilmesi için, alıcı-verici elektroniğinin iyileştirilmesi gerekmektedir. Bu çalışmada, iki boyutlu akustik çeviriciler için CMOS tabanlı ön alıcı-verici devresinin tasarımı gerçekleştirilmiştir. Devre, temel olarak, bir yüksek gerilim darbe üretici, alıcı-verici anahtarı, düşük gürültülü ön yükseltici ve dönüştürücü elemanın bağlantı dolgulamasından oluşmaktadır. Medical ultrasonic imaging systems, in general, are composed of a transducer element and the transmit/receive electronics. One dimensional arrays produce a two-dimensional cross-sectional image of the medium. With recent advances in transducer technology, the fabrication of 2-D arrays became feasible, which can be used for 3-D (volumetric) imaging. However, the Nyquist criterion restricts transducer dimensions, which results in relatively less sensitive array elements. Consequently, for an image of acceptable quality, the receiver electronics must be improved. In this study, the design of a CMOS based transmit-receive front-end electronic for 2-D transducer arrays is described. The circuit is composed of a high voltage pulser, a transmit-receive switch, a low noise amplifier, and a bonding pad for connction to the transducer element. IEEE; Tubitak; Istanbul Teknik Univ; Aselsan; Profile Telre; TURCom; Sgi; Datacore; Divit Publisher's Version