Open Access

ARTICLE

A Resource-Efficient Convolutional Neural Network Accelerator Using Fine-Grained Logarithmic Quantization

Hadee Madadum^*, Yasar Becerikli

Department of Computer Engineering, Kocaeli University, Kocaeli, 41380, Turkey

* Corresponding Author: Hadee Madadum. Email:

Intelligent Automation & Soft Computing 2022, 33(2), 681-695. https://doi.org/10.32604/iasc.2022.023831

Received 23 August 2021; Accepted 22 November 2021; Issue published 08 February 2022

Abstract

Convolutional Neural Network (ConNN) implementations on Field Programmable Gate Array (FPGA) are being studied since the computational capabilities of FPGA have been improved recently. Model compression is required to enable ConNN deployment on resource-constrained FPGA devices. Logarithmic quantization is one of the efficient compression methods that can compress a model to very low bit-width without significant deterioration in performance. It is also hardware-friendly by using bitwise operations for multiplication. However, the logarithmic suffers from low resolution at high inputs due to exponential properties. Therefore, we propose a modified logarithmic quantization method with a fine resolution to compress a neural network model. In experiments, quantized models achieve a negligible loss of accuracy without the need for retraining steps. Besides this, we propose a resource-efficient hardware accelerator for running ConNN inference. Our design completely eliminates multipliers with bit shifters and adders. Throughput is measured in Giga Operation Per Second (GOP/s). The hardware utilization efficiency is represented by GOP/s per block of Digital Signal Processing (DSP) and Look-up Tables (LUTs). The result shows that the accelerator achieves resource efficiency of 9.38 GOP/s/DSP and 3.33 GOP/s/kLUTs.

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