Low-Complexity 4-D IIR Filters for Multi-Depth Filtering and Occlusion Suppression in Light Fields
Namalka Liyanage, Chamith Wijenayake, Chamira U. S. Edussooriya, Arjuna Madanayake, Pan Agathoklis, Eliathamby Ambikairajah, Len T. Bruton · 2018
Light field signal processing allows manipulation of a rich set of information captured from a scene to achieve real-time depth filtering and occlusion suppression. Low-complexity four-dimensional infinite impulse response digital filters for simultaneous depth filtering and occlusion suppression over multiple depths in light fields are proposed. A low-complexity two-dimensional separable approach is employed to design the proposed filters having multiple frequency-planar pass-bands/stopbands in the four-dimensional spatial frequency domain, that can be electronically tuned to enhance/reject planar objects at multiple depths in a light field. Filter synthesis details are provided with specific design examples corresponding to 2-passband and 1-stopband cases. Numerically generated and Lytro camera captured light fields are used to verify the effectiveness of the proposed multi-depth-pass and multi-depth-reject filters. For synthetic light field inputs these filters confirm an average denoising, depth filtering and occlusion suppression performance of 20 dB, 20 dB, and 30 dB, respectively.