Forward stagewise regression with multilevel memristor for sparse coding  

作　　者：Chenxu Wu Yibai Xue Han Bao Ling Yang Jiancong Li Jing Tian Shengguang Ren Yi Li Xiangshui Miao 

机构地区：[1]School of Integrated Circuits,Huazhong University of Science and Technology,Wuhan 430074,China [2]Hubei Yangtze Memory Laboratories,Wuhan 430205,China

出　　处：《Journal of Semiconductors》2023年第10期105-113,共9页半导体学报（英文版）

基　　金：This work was supported by the National Key R&D Program of China(Grant No.2019YFB2205100);in part by Hubei Key Laboratory of Advanced Memories.

摘　　要：Sparse coding is a prevalent method for image inpainting and feature extraction,which can repair corrupted images or improve data processing efficiency,and has numerous applications in computer vision and signal processing.Recently,sev-eral memristor-based in-memory computing systems have been proposed to enhance the efficiency of sparse coding remark-ably.However,the variations and low precision of the devices will deteriorate the dictionary,causing inevitable degradation in the accuracy and reliability of the application.In this work,a digital-analog hybrid memristive sparse coding system is pro-posed utilizing a multilevel Pt/Al_(2)O_(3)/AlO_(x)/W memristor,which employs the forward stagewise regression algorithm:The approxi-mate cosine distance calculation is conducted in the analog part to speed up the computation,followed by high-precision coeffi-cient updates performed in the digital portion.We determine that four states of the aforementioned memristor are sufficient for the processing of natural images.Furthermore,through dynamic adjustment of the mapping ratio,the precision require-ment for the digit-to-analog converters can be reduced to 4 bits.Compared to the previous system,our system achieves higher image reconstruction quality of the 38 dB peak-signal-to-noise ratio.Moreover,in the context of image inpainting,images containing 50%missing pixels can be restored with a reconstruction error of 0.0424 root-mean-squared error.

关 键 词：forward stagewise regression in-memory computing MEMRISTOR sparse coding 

分 类 号：TN60[电子电信—电路与系统] TP391.41[自动化与计算机技术—计算机应用技术]