Recently proposed Generalized Time-domain Velocity Vector (GTVV) is a generalization of relative room impulse response in spherical harmonic (aka Ambisonic) domain that allows for blind estimation of early-echo parameters: the directions and relative delays of individual reflections. However, the derived closed-form expression of GTVV mandates few assumptions to hold, most important being that the impulse response of the reference signal needs to be a minimum-phase filter. In practice, the reference is obtained by spatial filtering towards the Direction-of-Arrival of the source, and the aforementioned condition is bounded by the performance of the applied beamformer (and thus, by the Ambisonic array order). In the present work, we suggest to circumvent this problem by properly modelling the GTVV time series, which permits not only to relax the initial assumptions, but also to extract the information therein is a more consistent and efficient manner, entering the realm of blind system identification. Experiments using measured room impulse responses confirm the effectiveness of the proposed approach.

翻译：近期提出的广义时域速度矢量（GTVV）是球谐（即Ambisonic）域中相对房间脉冲响应的推广，可实现对早期回波参数（如各反射分量的方向与相对延迟）的盲估计。然而，推导出的GTVV闭式表达式严格依赖于若干假设，其中最关键的是参考信号的脉冲响应需为最小相位滤波器。实际应用中，参考信号通过对声源到达方向进行空间滤波获得，而上述条件受限于所用波束成形器（进而受限于Ambisonic阵列阶数）的性能。本研究提出通过合理建模GTVV时间序列来规避该问题，该方法不仅能放宽初始假设，还能以更一致且高效的方式提取其中蕴含的信息，从而进入盲系统辨识领域。基于实测房间脉冲响应的实验验证了所提出方法的有效性。