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Günümüzdeki en revaçta araştırma alanlarından birisi kullanıcılara gelişmiş çoklu-ortam servisleri sağlayabilmek adına 3 Boyutlu (3B) video Kalite Deneyimini (KD) etkin olarak tahmin eden objektif metriklerin geliştirilmesidir. Fakat, literatürde standartlaşmış ve yaygın kullanılan bir metrik henüz bulunmamaktadır. Bu yüzden, Structural SIMilarity Index (SSIM) gibi 2 Boyutlu (2B) video kalite ölçümünde sıklıkla kullanılan metrikler 3B video kalite ölçümünde de kullanılmaktadır. Ancak bu metrikler İnsan Görme Sitemini (İGS) etkileyen 3B video bağlantılı özellikleri içermedikleri için güvenilir 3B video kalite ölçümü sağlamaktan oldukça uzaktırlar. Bunları göz önüne alarak, bu çalışmada, SSIM, zıtlık, hareket ve yapısal bilgi karakteristikleri gibi İGS’yi etkileyen 3B video özellikleri ile geliştirilmiştir. Geliştirilen SSIM metriği kullanılarak elde edilen sonuçlar, bu metriğin gelişmiş çoklu-ortam servisleri sağlayabilmek açısından etkinliğini kanıtlamaktadır.

In this paper, performance analysis of joint source-channel coding techniques for error-resilient transmission of three dimensional (3D) models are presented. In particular, packet based transmission scenarios are analyzed. The packet loss resilient methods are classified into two groups according to progressive compression schemes employed: Compressed Progressive Meshes (CPM) based methods and wavelet based methods. In the first group, layers of CPM algorithm are protected unequally by Forward Error Correction (FEC) using Reed Solomon (RS) codes. In the second group, embedded bitstream obtained from wavelet based coding is protected unequally with FEC as well. Both groups of methods are scalable with respect to both channel bandwidth and packet loss rate, i.e. they try to optimize FEC assignments with respect to channel bandwidth and packet loss rates (PLR). In-depth analysis of these techniques are carried out in terms of complexity, robustness to losses and compression efficiency. Experimental results show that wavelet based methods achieve considerably better quality compared to CPM based methods.

22nd IEEE Signal Processing and Communications Applications Conference (SIU) -- APR 23-25, 2014 -- Karadeniz Teknik Univ, Trabzon, TURKEY B. Akar, Gozde/0000-0002-4227-5606 WOS: 000356351400423 In the last two decades the Internet technology has boosted and the connection speeds have been incrased from kilobits to hundred megabits scale. With the rising coverage of the Internet and the usage of mobile devices such as tablets and smart phones, the usage of social media and especially multimedia elements has been increased rapidly. This increment in streaming multimedia created a need for the assessment of the user experience on multimedia and especially video. Even though there are different Video Quality Assessment (VQA) methods for that purpose, most of them are Full-Reference (FR) or Reduced-Reference (RR). In today's world with many mobile devices, the application of these methods are not possible since they need the reference data. The No-Reference (NR) video metrics are much more suitable for the case. In this paper, the main objective is to evaluate a previously proposed NR VQA metric with a new dataset and to compare the results to other high-performance NR metrics such as G.1070 and G.1070E which do not utilize spatial and temporal characteristics of a given video sequence. Evaluation and comparison results show the accuracy and robustness of the proposed metric. IEEE, Karadeniz Tech Univ, Dept Comp Engn & Elect & Elect Engn