3DStreaming: an open-source flexible framework for real-time 3D streaming services

The progress of three-dimensional 3D technologies, together with the wide diffusion of both Internet and broadband technologies, is paving the way to emerging live streaming services which have been conceived for delivering 3D video contents in real-time fashion to end users. Nowadays, the only available tools supporting stereoscopic 3D video services cannot be freely downloaded and require the adoption of owner stereoscopic players. Motivated by the lack of an effective solution, we developed a freeware and open source 3D live streaming framework, namely 3DStreaming. It provides stereoscopic 3D live streaming services over the Internet. In particular, it realizes a complete server implementation, offering the support for any transmission protocol and encoding scheme, as well as the full compatibility with any network architecture (i.e., LAN, MAN, Internet, and so on). At the same time, it allows users to use the preferable stereoscopic player and to render the video through any technique available for the chosen player. The overall performances of the proposed tool have been presented by testing its behavior in several network configurations (i.e., by varying network topology, coding technique, 3D representation format, and average encoding rate). All the measured metrics, which include the number of RTP segments that are transmitted and received, the frame loss ratio, and the PSNR, fully demonstrate the right behavior of the implemented tool in all the considered scenarios. We believe that, thanks to its high flexibility, this tool can be exploited by researchers working on stereoscopic-3D related issues to design, test, and evaluate novel and innovative algorithms, protocols, and network architectures.     

Tiled streaming for layered 3D virtual reality videos with viewport prediction

Multimedia Tools and Applications - In recent years, the demand of 3D video services has gradually increased. More and more bandwidth hungry applications are proposed, such as immersive media...     

Accumulative categorization: Online 3D shape classification for progressive collections

We present a new interactive and online approach to classify 3D shapes progressively by integrating online learning and user intervention. Our system, accumulative categorization, allows users to collect, classify and annotate 3D shapes interactively in an online circular manner. Our system learns a classification model from the annotation continuously and incrementally, and, in turn, classifies newly collected shapes. During this classification process, the user is allowed to interactively correct the errors in the results based on the actual requirements. The classification model is refined based on user intervention to capture the personalized intent of categorization. With the increasing of the user interactions and the accumulation of the classified shapes, the system produces more accurate classification of the subsequent shapes by the refined classification model. Experimental results demonstrate the effectiveness of our approach.     

Semantic-driven method for designing 3D busbars

Traditional busbar design is inefficient, costly, and error-prone because of frequent changes of requirements. This paper proposes a semantic-driven method for designing 3D busbars to solve this problem. The design process contains two main parts, namely, semantic-driven routing design and automatic routing segmentation. Semantic-driven routing design creates a relation table between electrical semantics and 3D modeling parameters, as well as helps designers create routings efficiently using electrical parameters as input. Automatic routing segmentation can convert routings into busbar segments that also include manufacturing information. Because the design operations are associated with one another, the resulting busbars can automatically be changed in real time when requirements are changed.     

Rate-distortion optimization for progressive compression of 3D mesh with color attributes

We propose a new lossless progressive compression algorithm based on rate-distortion optimization for meshes with color attributes; the quantization precision of both the geometry and the color information is adapted to each intermediate mesh during the encoding/decoding process. This quantization precision can either be optimally determined with the use of a mesh distortion measure or quasi-optimally decided based on an analysis of the mesh complexity in order to reduce the calculation time. Furthermore, we propose a new metric which estimates the geometry and color importance of each vertex during the simplification in order to faithfully preserve the feature elements. Experimental results show that our method outperforms the state-of-the-art algorithm for colored meshes and competes with the most efficient algorithms for non-colored meshes.     

A streaming edge sampling method for network visualization

Knowledge and Information Systems - Visualization strategies facilitate streaming network analysis by allowing its exploration through graphical and interactive layouts. Depending on the strategy...     

流媒体缓存分散式存储转换方法

在移动网络环境下为了降低访问终端位置变化给流媒体缓存应用效果带来的影响,借鉴分段缓存的思路,提出一种在流媒体缓存应用中使用的分散存储转换方法.在分散式存储转换方法中,利用分散函数的技术对流媒体缓存算法的缓存内容选取和释放内容选取两方面工作进行了修改.针对典型的流媒体缓存算法,通过模拟测试表明了分散式存储转换方法能提升流媒体缓存在移动网络环境下的工作效果.     

SVD lossy adaptive encoding of 3D digital images for ROI progressive transmission

In this paper, we propose an algorithm for lossy adaptive encoding of digital three-dimensional (3D) images based on singular value decomposition (SVD). This encoding allows us to design algorithms for progressive transmission and reconstruction of the 3D image, for one or several selected regions of interest (ROI) avoiding redundancy in data transmission. The main characteristic of the proposed algorithms is that the ROIs can be selected during the transmission process and it is not necessary to re-encode the image again to transmit the data corresponding to the selected ROI. An example with a data set of a CT scan consisting of 93 parallel slices where we added an implanted tumor (the ROI in this example) and a comparative with JPEG2000 are given.     

A retargeting method for stereoscopic 3D video

Computational Visual Media - We propose a disparity-constrained retargeting method for stereoscopic 3D video, which simultaneously resizes a binocular video to a new aspect ratio and remaps the...     

Metamorphosis of 3D polyhedral models using progressive connectivity transformations

Three-dimensional (3D) metamorphosis is a powerful technique to produce a 3D shape transformation between two or more existing models. We propose a novel 3D morphing technique that avoids creating a merged embedding that contains the faces, edges, and vertices of two given embeddings. This novel 3D morphing technique dynamically adds or removes vertices to gradually transform the connectivity of 3D polyhedrons from a source model into a target model and simultaneously creates the intermediate shapes. In addition, a priority control function provides the animators with control of arising or dissolving of input models' features in a morphing sequence. This is a useful tool to control a morphing sequence more easily and flexibly. Several examples of aesthetically pleasing morphs are demonstrated using the proposed method.     

Joint reversible watermarking and progressive compression of 3D meshes

A new reversible 3D mesh watermarking scheme is proposed in conjunction with progressive compression. Progressive 3D mesh compression permits a progressive refinement of the model from a coarse to a fine representation by using different levels of detail (LoDs). A reversible watermark is embedded into all refinement levels such that (1) the refinement levels are copyright protected, and (2) an authorized user is able to reconstruct the original 3D model after watermark extraction, hence reversible. The progressive compression considers a connectivity-driven algorithm to choose the vertices that are to be refined for each LoD. The proposed watermarking algorithm modifies the geometry information of these vertices based on histogram bin shifting technique. An authorized user can extract the watermark in each LoD and recover the original 3D mesh, while an unauthorized user which has access to the decompression algorithm can only reconstruct a distorted version of the 3D model. Experimental results show that the proposed method is robust to several attack scenarios while maintaining a good compression ratio.     

Packet loss in peer-to-peer video streaming over the Internet

Peer-to-peer streaming has recently gained attention as an effective solution to support large scale media streaming applications over the Internet. One of the main challenges of peer-to-peer video streaming is the cumulative impact of the Internet packet loss due to the decoding dependency of the compressed video frames. In this paper we study the impact of the Internet packet loss on the performance of peer-to-peer video streaming systems, and analyze the efficiency of various packet loss recovery policies in such systems. Our analytical and simulation results show how the Internet packet loss can affect the performance of peer- to-peer video streaming systems and how different packet loss recovery policies can be effective for such systems. Our analysis results give us some insights that can be used in designing efficient peer-to-peer video streaming systems.     

Methodology for tolerance design using quality loss function

In this paper, we develop a methodology for tolerance design that focuses on total variability from the target value. A general optimization model is developed to allocate tolerances to assembly parts. The constraint for the optimization model is the requirment for assembly tolerances or variability and cost is related to the total cost to reduce variance for the components and loss due to variation from target for the assembly. Different quality loss functions are also discussed.     

A progressive transmission capable diagnostically lossless compression scheme for 3D medical image sets

This paper presents a novel and efficient diagnostically lossless compression for 3D medical image sets. This compression scheme provides the 3D medical image sets with a progressive transmission capability. An automated filter-and-threshold based preprocessing technique is used to remove noise outside the diagnostic region. Then a wavelet decomposition feature vector based approach is applied to determine the reference image for the entire 3D medical image set. The selected reference image contains the most discernible anatomical structures within a relative large diagnostic region. It is progressively encoded by a lossless embedded zerotree wavelet method so the validity of an entire set can be determined early. This preprocessing technique is followed by an optimal predictor plus a 1st-level integer wavelet transform to de-correlate the 3D medical image set. Run-length and arithmetic coding are used to further remove coding redundancy. This diagnostically lossless compression method achieves an average compression of 2.1038, 2.4292, and 1.6826 bits per pixel for three types of 3D magnetic resonance image sets. The integrated progressive transmission capability degrades the compression performance by an average of 7.25%, 6.60%, and 4.49% for the above three types. Moreover, our compression without and with progressive transmission achieves better compression than the state-of-the-art.     

A mesh-geometry based method for coupling 1D and 3D elements

When conducting a finite element analysis (FEA) one way to reduce the total number of degrees of freedom is to use a mixed-dimensional model. Using beam elements to model long and slender components can significantly reduce the total number of elements. Problems arise when trying to connect elements with different dimensions in part due to incompatible degrees of freedom between different types of finite elements. This paper focuses on problems that occur in coupling beams and solids, which means coupling 1D and 3D finite elements. This paper presents a mesh-based solution to these problems only using specific arrangements of classical 1D and 3D finite elements without requiring the use of additional constraint equations. Two alternative solutions are detailed, evaluated and compared in this paper through series of computational experiments. The implementation of both solutions is also presented and involves mesh and geometry processing operations along with an adaptation of boundary representation (BREP) classical data structures.     

A new approach for packet loss measurement of video streaming and its application

Packet loss is of great importance as a metric that characterizes the network’s performance, and is crucial for video applications, congestion control and routing. Most of existing measurement tools can indicate the packet loss of network links instead of the actual packet loss of individual application. On the other hand, because occurrence of packet loss behavior is relatively rare and its duration is short, active measuring methods need to inject a large number of packets and run for a long time for reporting accurate estimates, which would introduce additional intrusiveness to the network and perturb user traffic. In this paper, we present a new packet loss estimation technique by making use of user_data field of video, which is less intrusive since it does not affect video playing and does not need to inject extra probing stream. It can also provide the packet loss detailed information of I,P,B frames. The accuracy of the algorithm has been evaluated with both simulations and experiments over real-world Internet paths. In addition, we analyze the video quality distortion caused by packet loss of different frame types, and a real-time video quality monitoring system is built.     

3TP: an application-Layer protocol for streaming 3-D models

This paper addresses the problem of streaming progressively compressed three-dimensional (3-D) models over lossy networks. Out of all encoded packets that can be transmitted, we intelligently choose a subset of packets to be transmitted using transport control protocol in order to meet a distortion constraint, while transmitting the remaining packets using user datagram protocol to minimize the end-to-end delay. We call this new application-layer protocol 3-D models transport protocol. We show the effectiveness of this protocol both experimentally and theoretically. We compare the performance of the proposed protocol with systems that do not optimize transmission according to the content of the encoded bitstream. When the maximum distortion is 30, measured using the Hausdorff distance, we achieve savings in delay time ranging from 39% to 68% for packet-loss rates between 1% and 19%.