Exploring the efficiency of image metric for assessing the visual quality of 3D mesh model

Recent developments in 3D graphics technology have led to extensive processes on 3D meshes(e.g.,compression,simplification,transmission and watermarking),these processes unavoidably cause the visual perceptual degradation of the 3D objects.The existing mesh visual quality evaluation metrics either require topology constrain or fail to reflect the perceived visual quality.Meanwhile,for the 3D objects that are observed on 2D screens by the users,it is reasonable to apply image metric to assess the distortion caused by mesh simplification.We attempt to explore the efficiency of image metric for assessing the visual fidelity of the simplified 3D model in this paper.For this purpose,several latest and most effective image metrics,2D snapshots,number and pooling algorithms are involved in our study,and finally tested on the IEETA simplification database.The statistical data allow the researcher to select the optimal parameter for this image-based mesh visual quality assessment and provide a new perspective for the design and performance assessment of mesh simplification algorithms.

Automatic LOD selection using viewpoint entropy

Discrete Level of Detail (LOD) strategy is an effective solution for balancing the inherentcontradiction between quality and speed in computer graphics. However, application ofthis strategy requires both the appropriate selection approach and the visually comfortable transition procedure to reduce the popping effects introduced by switching betweendifferent levels. In this paper, a novel automatic LOD selection method based on viewpoint entropy was proposed. Firstly, the traditional calculation method of viewpointentropy contained in a scene was improved for the preprocessing of LOD models. Then,the runtime rendering scheme combined with our selection method was designed forbalance of frame rate during real-time rendering, and a novel smoothing LOD transitionstrategy based on Alternate Frame Rendered (ALR) was put forward for eliminationof popping effects. Finally, an example of complex scene combined with our proposalwas researched to verify its real-time performance and ability in holding continuity ofrendered images. Experimental studies show the effectiveness for stabilizing frame rateand improvements in reducing loss of continuity.

UUV formation system modeling and simulation research based on Multi-Agent Interaction Chain

Unmanned Underwater Vehicle(UUV)formation system has an important role in the utilization of marine resource.In order to provide an efficient method to research modeling and simulation of UUV formation in the marine environment,the novel approach based on Multi-Agent Interaction Chain was proposed for the UUV formation system.Firstly,Multi-Agent Interaction Chain was analyzed,which mainly considered task and role of UUV in the formation,and the overall modeling process of UUV formation system based on Multi-Agent Interaction Chain was established.Then,the static structure of Multi-Agent Interaction Chain was researched focusing on Hybrid UUV-Agent model structure from the UUV-Agent State-Set and UUV-Agent Rule-Base which were the two aspects to strengthen reliability of interaction chain;the dynamic mechanism of Multi-Agent Interaction Chain was designed,which was focused on collaboration model and communication model through the Adaptive Dynamic Contract Net Protocol and KQML/XML/RTI.Finally,three experiments were established to verify the validity and effectiveness of proposed modeling approach for UUV formation system.Simulation results show the proposed model has good performance,which has important theoretical innovation and application prospects.

An investigation on annoyance caused by road-vehicle noise based on the autocorrelation function

The objective of this study is to reveal the cause of noise annoyance based on its perceptual properties. The available physical factors extracted from the autocorrelation function （ACF） were used to explain the primary sensations and representative perceptual properties of road-vehicle noise. Two novel factors, EMD and ESM, used especially for measuring fluctuation and smoothness of the ACF envelope, were proposed. It should be pointed out that if φ1 was not the maximum value except φ（0）, both φ and φ- were suggested to be added. Three primary sensations loudness, pitch, and timbre have been acquired by applying the princi- pal component analysis to ACF factors extracted from 232 noise samples. From 10 subjects, annoyance scale values were investigated using the magnitude estimation approach under wellcontrolled experimental conditions. It is realized that there certainly exist elementary factors for every primary sensation. Different ACF characteristics can induce diverse dominant sensation, which would control or determine the perceptual properties of the noise. The variability of dominant sensation and the priority difference in primary sensations will bring out subjective annoyance. Moreover, the mixture of elementary factors would confuse the auditory features, and induce subjective annoyance. In other words, it is the chaos of perceptual properties that cause and affect noise annoyance.