Multiview passive 3-D displays, such as those based on lenticular or
parallax-barrier technologies, require multiplexing of views into a single same-size RGB image. Thus, multiplexing of N views necessitates N:1 sub-sampling of each view and must be preceded by suitable lowpass filtering to prevent, or at least reduce, aliasing. Without such filtering, objectionable "jagged" edges, distorted textures, or Moire patterns are perceived although, admittedly, these effects are not as disturbing as in the case of single-view sub-sampling without multiplexing with other views. In
this paper, unlike in our previous work, we consider anti-alias filtering derived from a non-orthogonal lattice. First, we approximate pixel layout for each view (sampling pattern) by a two-dimensional lattice; we find parameters of the lattice by minimizing a mismatch error between lattice and single-view points. Then, based on lattice parameters, we find frequency-domain specifications of the anti-alias filter. The filter has hexagonal passband and thus is non-separable. Although previously we designed such filters for
floating-point implementations, here we opt for the more practical
fixed-point arithmetic; the resulting filters can be easily implemented on ubiquitous fixed-point DSP chipsets. The fixed-point filters slightly depart from the desired magnitude specifications, but when applied to actual multiview images they produce almost indistinguishable results from those obtained by floating-point counterparts.