Memristor-based BAM circuit implementation for image associative memory and filling-in

Abstract

Associative memory and filling-in are two essential functions of the human brain. To implement these two brain-inspired functions in hardware, we proposed a memristor-based bidirectional associative memory (BAM) circuit in this paper. This circuit combines an online algorithm with a memristor array adjustment process, thus makes the circuit more universal for various tasks. The proposed circuit is constructed out of memristive synaptic circuits, IN modules and ACT modules. The memristive synaptic circuits utilize memristor arrays to represent weight matrix and operate corresponding operations hence make computing-in-memory and process information in parallel, which simplifies the complexity of circuit and improves the processing speed. The IN modules employ transistors as switches to choose the input layer hence can get initial information flow bidirectionally. The ACT modules perform activation function and can output continuous arbitrary real numbers. Thereby, both binary and gray-scale images can be tested in the proposed circuit. In addition to the hetero-association and filling-in results given in detail, the retrieval rates of the proposed circuit with the impact of different degrees of noise and the number of stored patterns are also evaluated and compared with software-based BAM. The simulation has experimented via MATLAB and PSpice, and the corresponding results show a remarkable performance of the proposed circuit. The influence of memristor’s stuck-at-fault is also considered. In comparison with software-based BAM and similar memristor-based neural network circuit, the proposed circuit performs better in processing speed.