Fig. 2.

Different combinations of source locations and reconstruction locations subject to spatial aliasing in SS and IR. Three regions S₀, S₁, and S₂ are defined in Equations (8), (16), and (22), respectively. The first line radiating from the origin O represents the range of source locations for SS, while the second line radiating from the tip of the first line represents the range of reconstruction locations for IR. A solid line means no aliasing, while a dotted line means aliasing. (a) Spatial aliasing in UBP. The innermost two-way Nyquist zone S₂ is an aliasing-free region. (b) Spatial aliasing in UBP with spatial interpolation. Spatial interpolation removes spatial aliasing in three cases of IR, making the one-way Nyquist zone S₁ an aliasing-free region. The dotted lines representing the three cases in (a) are changed to blue-solid lines in (b). (c) Spatial aliasing in UBP with temporal filtering and spatial interpolation. Temporal filtering extends the one-way Nyquist zone S₁ in (b) to $S_1^{\prime }$ in (c), and the original S₁ is marked as a blue-dashed circle for reference. Spatial interpolation further makes $S_1^{\prime }$ an aliasing-free region.