Optimized Image Scaling Processor using VLSI

Abstract-A high-quality algorithm is proposed for VLSI implementation of an image scaling processor. The proposed image scaling algorithm consists of a sharpening spatial filter, a clamp filter, and a bilinear interpolation. To reduce the blurring and aliasing artifacts produced by the bilinear interpolation, the sharpening spatial and clamp filters are added as prefilters. To minimize the memory buffers and computing resources for the proposed image processor design, a T-model and inversed T-model convolution kernels are created for realizing the sharpening spatial and clamp filters. Furthermore, two T-model or inversed T-model filters are combined into a combined filter which requires only a one-line-buffer memory. Moreover, a reconfigurable calculation unit is invented for decreasing the hardware cost of the combined filter. Moreover, the computing resource and hardware cost of the bilinear interpolator can be efficiently reduced by an algebraic manipulation and hardware sharing techniques. The VLSI architecture in this work can achieve 280 MHz with 6.08-K gate counts, and its core area is 30 378 μm2 synthesized by a 0.13-μm CMOS process. Compared with previous lowcomplexity techniques, this work reduces gate counts by more than 34.4% and requires only a one-linebuffer memory. Index Terms Bilinear, clamp filter, image zooming, reconfigurable calculation unit (RCU), sharpens spatial filter, VLSI