Abstract
High-quality and high-resolution depth maps have opened tremendous possibilities for various applications, such as ARlVR display, 3D reconstruction, image refocusing, and view synthesis. But high-resolution depth estimation requires heavy hardware resources. Depth upsampling with weighted mode filtering is an efficient way to overcome this challenge. However, its hardware implementation has two major design issues: large on-chip memory for storing high-precision depth labels and high logic cost for computing adaptive range weight. In this work, we present two techniques, histogram candidate mapping and binary range weight kernel, which can reduce on-chip memory size and logic gate count by 46.9 % and 64.3 % respectively. Furthermore, we also implement a VLSI circuit for 4K Ultra-HD depth video upsampling using TSMC 40nm technology. It has 25.5-KB SRAM and 420K-gate logic, and the core area is 1.1 imes 1.1 mathrm{mm}^{2}. When operating at 200 MHz and 0.9V, it delivers 320M pixel/s to support 4K Ultra-HD depth video at 40 fps, and consumes 104 mW based on post-layout simulation.