一种自适应图像插值算法及加速引擎的协同设计

Adaptive Image Interpolation Algorithm and Acceleration Engine Co-Design

为提高高清彩色图像超分辨率重建效果,该文提出了一种基于边缘对比度的新型自适应图像插值算法。使用边缘对比度检测和不同尺度的感受野来自适应选择Lanczos插值的系数,自适应性和不同感受野可以进一步提升图像放大质量,图像质量相比于双线性插值平均峰值信噪比(PSNR)提高1.1 dB,结构相似度(SSIM)提高0.025,图像感知相似度(LPIPS)提高0.051,相比于双三次插值平均PSNR提高0.34 dB,SSIM提高0.01,LPIPS提高0.033。同时为减少硬件资源以及提高存储效率协同设计了一种高并行、高能效的加速插值引擎架构,通过两级数据重用和系数脉动机制极大提高计算访存比。加速引擎在16 nm工艺库的综合结果达到2 GHz时钟频率;在Xilinx Zynq Ultra scale+xczu15eg FPGA上工作频率达到200 MHz,帧速度(fps)达到60的实时性能。

In order to improve the super-resolution reconstruction effect of the high-definition color image,a new adaptive image interpolation algorithm based on edge contrast is proposed,which chooses adaptively the coefficients of Lanczos interpolation by edge contrast detection and receptive fields with different scales.Adaptability and diverse receptive fields can further improve the quality of image magnification.Compared with the bilinear interpolation algorithm,the Peak Signal to Noise Ratio(PSNR),Structural SIMilarity(SSIM)and Learned Perceptual Image Patch Similarity(LPIPS)are improved by 1.1 dB,0.025,0.051,respectively.Compared with the bicubic interpolation algorithm,the PSNR,SSIM and LPIPS are improved by 0.34 dB,0.01,0.033,respectively.Moreover,in order to reduce the hardware resources and improve the storage efficiency,a high parallelized and high efficiency accelerated architecture is proposed.A 2-level data reuse and coefficients pulsation mechanism are employed to improve the computation-memory access ratio greatly.The synthesis result of the acceleration engine in the 16nm process library can reach the 2 GHz clock frequency.The operating frequency of FPGA project deployed in Xilinx Zynq Ultra scale+xczu15eg can reach up to 200 MHz as well,which means that the algorithm can adapt to the frame rate(fps)up to 60.