Shihong Chen

3D Panning Based Sound Field Enhancement Method for Ambisonics

When conventional first order Ambisonics system uses four loudspeaker with platonic solid layout to reconstruct sound field, the 3D acoustic field effect is limited. A new signal distribution method is proposed to enhance the reproduced field without increasing loudspeakers. First, a platonic solid is extended to get more new vertexes, based on the traditional Ambisonics signal distribution method, original field signal is distributed to loudspeakers at original and new vertexes of platonic solid. Second, signals of loudspeakers at new vertexes are distributed to loudspeakers at original vertexes by a new 3D panning method, then loudspeakers at new vertexes of platonic solid are deleted, only original vertexes of platonic solid are left. The proposed method can improve the quality of the reconstructed sound field and will not increase the complexity of loudspeaker layout in practice. Results are verified through objective and subjective experiments.

Spatial perception reproduction of sound event based on sound properties

A new method for estimating gain factors in amplitude panning system is proposed. The method is based on particle velocity and balanced sound energy formulation. A scale factor is employed in amplitude panning system and thus, an overdetermined system of equation is derived in particle velocity equation. To obtain the analytic solution of the overdetermined equation, the sound energy identical formula is considered and then the unique gain factors are estimated. The proposed method is able to reproduce sound source direction and control the distance perception in a flexible two- or three-dimension loudspeaker setup. Subjective evaluations show that the proposed technique in an aspheric loudspeaker setup maintains the sound direction and controls the distance perception at the listening point.

Sound physical property matching between non central listening point and central listening point for NHK 22.2 system reproduction

NHK has proposed a famous 3D audio system: 22.2 multi-channel system, but its loudspeakers are too many and are troublesome to put in home. Ando and Wang has proposed two simplification methods to reduce its channel number, but only 3D sound field at the central listening point can be recovered well by NHK 22.2 system and its simplified systems, the listening experience at a non central listening point is worse than that at the central listening point. In real life, listeners may stay at arbitrary listening point: central or non central point. Conventional pressure matching and particle matching method could be used for non central zone sound field reproduction, but they have some theoretical shortcomings. To address these problems, this paper propose a universal non central listening point sound field reproduction method by matching sound physical property between a non central listening point and the central listening point. Subjective and objective experiments show the effectiveness of the proposed method.

3D Sound Field Reproduction at Non Central Point for NHK 22.2 System

Reducing channel number is convenient for NHK 22.2 system in loudspeaker layout and good for the application of NHK 22.2 in family environment. In 2011, Akio Ando has proposed a down-mixing method which could simplify 22.2 multichannel system to 10.2 and 8.2 multichannel system, but this method only could perfect reproduce 3D sound field at a central listening point. In practice, people may stay at a non central point, Ando’s method could not maintain sound physical properties at non central point well. Conventional non central zone sound filed reproduction methods such as pressure matching method and particle velocity matching method have theoretical limitations. This paper propose a general down-mixing method basing on the position of listening point and sound physical properties, it could produce a sweet spot at any non central point in reconstruction field and reduce channel number. In experiments, the proposed method simplifies 22 channel system to 10 channel system, experimental results demonstrate that it performs better than traditional method at non central point sound field reconstruction.

An emergency scenario reconstruction system based on ESMM event situation model

In order to keep decision-makers better informed with emergencies, it is useful to retrieve the user-oriented disaster relevant event information in an aggregated results list through meta- search engine. However, emergent event is dynamic which makes it difficult to use fixed search word or word combinations. This paper proposes an event situation monitoring model (ESMM) event detection model, which realizes heuristic query word vector dynamic expanding by adopting emergency fuzzy scenario reasoning ontology cluster. Disaster event facet information automatic searching is discussed as an example in this paper. The experimental results show that the proposed method can increase accuracy and extra clues not supplied by commercial search engines, which can be used as a supplement information source for government and individuals.

Super-resolution for face image with an improved K-NN search strategy

Recently, neighbor embedding based face super-resolution (SR) methods have shown the ability for achieving high-quality face images, those methods are based on the assumption that the same neighborhoods are preserved in both low-resolution (LR) training set and high-resolution (HR) training set. However, due to the “one-to-many” mapping between the LR image and HR ones in practice, the neighborhood relationship of the LR patch in LR space is quite different with that of the HR counterpart, that is to say the neighborhood relationship obtained is not true. In this paper, we explore a novel and effective re-identified K-nearest neighbor (RIKNN) method to search neighbors of LR patch. Compared with other methods, our method uses the geometrical information of LR manifold and HR manifold simultaneously. In particular, it searches K-NN of LR patch in the LR space and refines the searching results by re-identifying in the HR space, thus giving rise to accurate K-NN and improved performance. A statistical analysis of the influence of the training set size and nearest neighbor number is given, experimental results on some public face databases show the superiority of our proposed scheme over state-of-the-art face hallucination approaches in terms of subjective and objective results as well as computational complexity.

Recursive Decomposition of Software Process

Based on the theory of the structure of the computable mathematical function, the operator of the software process, algorithm structure and architecture are defined mathematically in this paper. With the expression of combinational functions, the mathematical definition of the decomposition of operator and its operation is discussed. Finally, the mathematical formula of the decomposition of operator-operator recursive decomposition formula is established. While focusing on solvable problems, the concept of the computing prototype tree and its formula proposed in this paper has generality.

A distributed dynamic clustering algorithm for wireless sensor networks

This paper proposes a distributed dynamic k-medoid clustering algorithm for wireless sensor networks (WSNs), DDKCAWSN. Different from node-clustering algorithms and protocols for WSNs, the algorithm focuses on clustering data in the network. By sending the sink clustered data instead of practical ones, the algorithm can greatly reduce the size and the time of data communication, and further save the energy of the nodes in the network and prolong the system lifetime. Moreover, the algorithm improves the accuracy of the clustered data dynamically by updating the clusters periodically such as each day. Simulation results demonstrate the effectiveness of our approach for different metrics.