VLSI architecture design of layer-based bilateral and median filtering for 4k2k videos at 30fps

Bilateral filtering (BLF) and median filtering (MF) are key components in many applications. As the image resolution grows rapidly, implementation of efficient filtering is highly demanded. In this paper, we present a unified VLSI architecture that is able to compute both kinds of filters for 4k2k videos at 30fps. One feature of this design is that we leverage an emerging layer-based algorithm for both BLF and MF, which turns the non-linear BLF or MF into a set of linear filtering followed by output interpolation. It allows more accurate approximation than previous works. Moreover, to address the introduced design challenges of filter units and comparison units, we propose an architecture with moving sum method (MSM) of box filtering and a parallel component selector (PCS), respectively. The MSM requires only one line buffer, and the PCS architecture allows us to complete the comparison in one cycle. Furthermore, a shared pre-computation unit is also proposed to support both kinds of filters. As a result, our design costs only 6.33KB on-chip memory and 161.5K logic gates to support both BLF and MF. It is much efficient than existing architectures which support BLF only.