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（Generalized Time-domain Velocity Vector，GTVV）是球谐函数（亦称Ambisonic）域中相对房间脉冲响应的推广形式，能够实现早期回声参数的盲估计：包括单个反射的方向和相对时延。然而，GTVV的闭式表达式推导需满足若干假设条件，其中最重要的是参考信号的脉冲响应必须为最小相位滤波器。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，上述条件受限于所采用波束成形器的性能（进而受限于Ambisonic阵列阶数）。本研究提出通过合理建模GTVV时间序列来规避该问题，该方法不仅放宽了初始假设条件，还能以更一致且高效的方式提取其中信息，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方法的有效性。