Differentiable equivalent source method: Joint optimization of equivalent source positions and strengths with implicit geometry constraints

The equivalent source method (ESM) is widely used for sound field reconstruction due to its flexibility. However, optimizing source configurations remains challenging because ESM requires all sources to be located outside the reconstruction region. Identifying optimal source positions while satisfying these geometric constraints is an underexplored challenge. To address this, we propose a differentiable equivalent source method (DiffESM) for joint optimization of source positions and strengths. By employing a neural signed distance function to represent feasible regions of the source positions, DiffESM enables gradient-based optimization while enforcing geometric constraints. Preliminary results demonstrated that DiffESM achieved higher reconstruction accuracy than conventional ESMs.