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Publication Metadata only A new scalable multi-view video coding configuration for robust selective streaming of free-viewpoint TV(IEEE, 2007) Özbek, Nükhet; Tunalı, E. Turhan; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207Free viewpoint TV (FTV) is a new media format that allows a user to change his/her viewpoint freely. To this effect, multi-view video must be coded to sAtışfy two conflicting requirements: i) achieve high compression efficiency, and ii) allow view switching with low delay. This paper proposes a new encoding configuration for scalable multi-view video coding, which achieves a compromise between the two requirements. In the new scalable multi-view configuration, the base layer is encoded with inter-view prediction at a minimum acceptable quality, while enhancement layers for each view only depend on their respective base layers (with no interview prediction). Thus, the base layer shall be served to all users, while enhancement layers shall be served selectively to users depending on their channel bandwidth and viewing direction. We compare the compression efficiency of the proposed method with those of non-scalable multi-view coding (MVC) and simulcast (H.264/AVC of each view independently) solutions.Publication Metadata only H.264 long-term reference selection for videos with frequent camera transitions(IEEE, 2006) Özbek, Nükhet; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207Long-tern reference prediction is an important feature of the H.264/MPEG-4 AVC standard, which provides a tradeoff between compression gain and computational complexity. In this study, we propose a long-tern reference selection method for videos with frequent camera transitions to optimize compression efficiency at shot boundaries without increasing the computational complexity. Experimental results show up to 50% reduction in the number of bits (at the same PSNR) for frames at the border of camera transitions.Publication Metadata only Hierarchical representation and coding of 3D mesh geometry for transmission of surface/volume data(IEEE, 2006) Celasun, Işıl; Eröksüz, Serkan; Siddiqui, Rizwan A.; Doğan, Ertuğrul; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207Hierarchical mesh representation and mesh simplification have been addressed in computer graphics for adaptive level-of-detail rendering of 3D objects. In this paper, by using a new simplification method to design hierarchical 3D meshes such that each mesh level has Delaunay topology, we can obtain not only meshes with desired geometric properties, but also efficient compression of the mesh data. The hierarchical compression technique is based on a nearest-neighbor ordering of mesh node points. The baseline is the use of entropy coding of linear prediction between nearest neighbor node coordinates. Vector quantization is also employed just to be able to process efficiently stAtıştical dependences between prediction error vectors of a node. The compression method allows progressive transmission and quality scalability.Publication Metadata only Machine learning-based approach to identify formalin-fixed paraffin-embedded glioblastoma and healthy brain tissues(Spie-Int Soc Optical Engineering, 2022) N/A; Department of Electrical and Electronics Engineering; N/A; N/A; N/A; N/A; N/A; Department of Electrical and Electronics Engineering; Torun, Hülya; Batur, Numan; Bilgin, Buse; Esengür, Ömer Tarık; Baysal, Kemal; Kulaç, İbrahim; Solaroğlu, İhsan; Onbaşlı, Mehmet Cengiz; PhD Student; Undergraduate Student; PhD Student; Undergraduate Student; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; School of Medicine; School of Medicine; School of Medicine; School of Medicine; College of Engineering; N/A; N/A; N/A; N/A; 119184; 170305; 102059; 258783Glioblastoma is the most malignant and common high-grade brain tumor with a 14-month overall survival length. According to recent World Health Organization Central Nervous System tumor classification (2021), the diagnosis of glioblastoma requires extensive molecular genetic tests in addition to the traditional histopathological analysis of Formalin-Fixed Paraffin-Embedded (FFPE) tissues. Time-consuming and expensive molecular tests as well as the need for clinical neuropathology expertise are the challenges in the diagnosis of glioblastoma. Hence, an automated and rapid analytical detection technique for identifying brain tumors from healthy tissues is needed to aid pathologists in achieving an error-free diagnosis of glioblastoma in clinics. Here, we report on our clinical test results of Raman spectroscopy and machine learning-based glioblastoma identification methodology for a cohort of 20 glioblastoma and 18 white matter tissue samples. We used Raman spectroscopy to distinguish FFPE glioblastoma and white matter tissues applying our previously reported protocols about optimized FFPE sample preparation and Raman measurement parameters. One may analyze the composition and identify the subtype of brain tumors using Raman spectroscopy since this technique yields detailed molecule-specific information from tissues. We measured and classified the Raman spectra of neoplastic and non-neoplastic tissue sections using machine learning classifiers including support vector machine and random forest with 86.6% and 83.3% accuracies, respectively. These proof-of-concept results demonstrate that this technique might be eventually used in the clinics to assist pathologists once validated with a larger and more diverse glioblastoma cohort and improved detection accuracies.Publication Metadata only Multimodal speaker identification with audio-video processing(Ieee, 2003) Department of Computer Engineering; N/A; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Yemez, Yücel; Kanak, Alper; Erzin, Engin; Tekalp, Ahmet Murat; Faculty Member; Master Student; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; 107907; N/A; 34503; 26207In this paper we present a multimodal audio-visual speaker identification system. The objective is to improve the recognition performance over conventional unimodal schemes. The proposed system decomposes the information existing in a video stream into three components: speech, face texture and lip motion. Lip motion between successive frames is first computed in terms of optical row vectors and then encoded as a feature vector in a magnitude-direction histogram domain. The feature vectors obtained along the whole stream are then interpolated to match the rate of the speech signal and fused with mel frequency cepstral coeffcients (MFCC) of the corresponding speech signal. The resulting joint feature vectors are used to train and test a Hidden Markov Model (HMM) based identification system. Face texture images are treated separately in eigenface domain and integrated to the system through decision-fusion. Experimental results are also included for demonstration of the system performance.Publication Metadata only Quality assessment of asymmetric stereo video coding(IEEE, 2010) N/A; N/A; Department of Electrical and Electronics Engineering; Saygılı, Görkem; Gürler, Cihat Göktuğ; Tekalp, Ahmet Murat; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 26207It is well known that the human visual system can perceive high frequencies in 3D, even if that information is present in only one of the views. therefore, the best 3D stereo quality may be achieved by asymmetric coding where the reference (right) and auxiliary (left) views are coded at unequal PSNR. However, the questions of what should be the level of this asymmetry and whether asymmetry should be achieved by spatial resolution reduction or SNR (quality) reduction are open issues. Extensive subjective tests indicate that when the reference view is encoded at sufficiently high quality, the auxiliary view can be encoded above a low-quality threshold without a noticeable degradation on the perceived stereo video quality. This low-quality threshold may depend on the 3D display; e.g., it is about 31 dB for a parallax barrier display and 33 dB for a polarized projection display. Subjective tests show that, Above this PSNR threshold value, users prefer SNR reduction over spatial resolution reduction on both parallax barrier and polarized projection displays. It is also observed that, if the auxiliary view is encoded below this threshold value, symmetric coding starts to perform better than asymmetric coding in terms of perceived 3D video quality.Publication Metadata only Rate-visual-distortion optimized extraction with quality layers for scalable coding of stereo videos(Institute of Electrical and Electronics Engineers (IEEE), 2008) Özbek, Nükhet; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207The quality layers concept is proposed and adopted in the JSVM in order to ensure an optimal adaptation in a rate-distortion sense. In this paper it is extended to multiview case for scalable coding of stereo videos. Rate-visual-distortion optimized rate allocation among the views is necessary for efficient transport of 3DTV data over the Internet. This paper addresses a standard compatible approach to solve the problem. Experimental results are presented that demonstrate the effectiveness of the proposed method for several stereo videos.Publication Metadata only Scalable multi-view video coding for interactive 3DTV(IEEE, 2006) Özbek, Nükhet; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207A standard for scalable video coding (SVC) is currently being worked on by the ISO MPEG Group. Work on standardization of multiple-view video coding (MVC) has also recently started under the ISO MPEG. Although there are many approaches published on SVC and WC, there is no current work reported on scalable multi-view video coding (SMVC). This paper presents new coding structures for scalable stereo and multi-view video coding The proposed structures are implemented as extensions to the JSVM software and resulting bitrates and PSNR are demonstrated. SMVC can be used for transport of multiview video over IP for interactive 3DTV by dynamic adaptive combination of temporal, spatial, and SNR scalability according to network conditions.Publication Metadata only Scanning led array based volumetric display(IEEE, 2007) N/A; Department of Electrical and Electronics Engineering; Sayınta, Murat; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579This paper reports a novel volumetric display system using 1D LED arrays mounted on rotating platforms to create a quasi-holographic display. the system employs a 2D array of such modules and a special diffuser screen in front of them. a virtual 3D image pixel (voxel) appears behind the screen at the intersection of 2 rays emitted from 2 LEDs at different rotation angles. the basic concept is reported for the first time here. a subsystem demonstrator is developed using a single LED mounted on a polymer scanner platform rotating at 60Hz, which corresponds to the refresh rate of the display system. Large rotation angle and high modulation speeds are achievable with LEDs mounted on polymer scanners. an array of LEDs can be driven by a LED Driving IC, integrated with the polymer scanner.Publication Metadata only Scanning led array based volumetric display(IEEE, 2008) N/A; N/A; Department of Electrical and Electronics Engineering; Sayınta, Murat; Işıkman, Serhan Ömer; Ürey, Hakan; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 8579A novel quasi-holographic display concept is developed using Light Emitting Diode (LED) arrays on scanning platform. The display system is capable of providing smooth motion parallax and solving the accommodation -vergence rivalry. Each scanner module contains I D LED array mounted on a polymer scanner with a lens for imaging the LEDs onto a special diffuser screen. The scanning modules are actuated electromagnetically and the LEDs are driven with an external LED driving Field Programmable Gate Array (FPGA) circuitry designed for the purpose. The scanners have a natural frequency of 12.7 Hz, scan line of 21.5 degrees Total Optical Scan Angle (TOSA) and a quality factor of 20. The three dimensional (3D) display concept is proved with two of these modules by displaying two points sequentially at two different depths.