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声场全变分联合等效源优化方法

Optimization method for the total variational joint equivalent source of sound field

  • 摘要: 稀疏等效源法(sparse–equivalent source method, L1-ESM)能有效稀疏重建简单声源声场,且有较高重建精度,但因稀疏性局限,对相干声场的重建效果差。文章提出一种声场全变分联合等效源法(total variational joint equivalent source method, TV-ESM)的优化方法。该方法以阵列传声器到等效源点距离与阵列面到中心等效源点的距离差,作为等效源点声场贡献的评定依据,筛选等效源数量和位置,构建声场传递矩阵,以矩阵条件数为目标,优化等效源结构。该方法联合等效源结构特征和L1范数,构造全变分约束矩阵和全变分正则化声场稀疏重构模型,经凸优化解析源强稀疏表达。仿真分析和实验验证表明:采用TV-ESM法宽频段相干声源的声场重建误差低于10%,声像面积误差小于5%,单频多个重建点的声压幅度误差小于4%;与L1-ESM法相比,对简单源声场两者的重建精度一致,重构误差均低于5%,对相干源声场,TV-ESM方法重建误差比L1-ESM方法低20%。该方法拓展了稀疏等效源法的应用范围,不仅能有效重建简单源场,而且对空间扩展源场、近场和反射场等非严格稀疏相干声场有较好的重建效果。

     

    Abstract: The sparse equivalent source method (L1-ESM) can effectively sparsely reconstruct the sound field of a simple sound sources with high reconstruction accuracy, but due to the limitation of sparsity, the effect of reconstructing coherent sound field is poor. Therefore, a optimization method for the total variational joint equivalent source method (TV-ESM) of sound field is proposed, the distances from the array microphones to the equivalent source point and the distance difference from the array surface to the center equivalent source point are used to evaluate the contribution of the equivalent source point sound field and screen the number and position of equivalent sources for constructing the sound field transfer matrix; then, with the number of matrix conditions as the goal, the equivalent source structure is optimized, which combines the equivalent source structure characteristics and L1 norm to constructs the total variational constraint matrix and the total variational regularized sound field sparse reconstruction model, and analyzes the strong sparse expression of the source by the convex optimization. Through numerical analysis and method comparison, the sound field reconstruction error of a wide-band coherent sound source is less than 10%, the acoustic image area error is less than 5%, and the sound pressure amplitude error of multiple reconstruction points at a single frequency is less than 4%. Compared with the L1-ESM method, the reconstruction accuracy of the simple source sound field is consistent, and the reconstruction error is less than 5%, and the sound field reconstruction error of the TV-ESM method for coherent sources is 20% lower than that of the L1-ESM method.This method expands the application scope of the sparse equivalent source method, which can not only effectively reconstructs the simple source field, but also has a good reconstruction effect on the non-strict sparse coherent sound fields such as the spatially extension source field, near field and reflection field.

     

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