Sub-pixel downsampling of video with matching highly data re-use hardware architecture
Subpixel-based down-sampling is a method that can potentially improve the apparent resolution of a down-scaled image by controlling individual subpixels rather than pixels. However, the increased luminance resolution often comes at the price of chrominance distortion. A major challenge is to suppress color fringing artifacts while maintaining sharpness. In [1], we proposed a novel human visual quality based (HVS) subpixel downsampling method. In this paper, we propose a hardware-friendly subpixel based downsampling scheme based on our previous work which can achieve similar performance as [1] but eliminate all floating point operations with limited bandwidth and much better performance than Direct Pixel based Downsampling (DPD) and Pixel-based downsampling with Anti-aliasing Filter (PDAF). We further propose a hardware architecture for our subpixel downsampling method which is highly data re-useable. We are the first few, if not the first, to implement subpixel downsampling method to video by hardware. The design is implemented with TSMC 0.18um CMOS technology and costs 244k gates. At a clock frequency of 63 MHz, the architecture achieves real-time 1920×1080 subpixel downsampling at 30fps.