Dither NN: Hardware/Algorithm Co-Design for Accurate Quantized Neural Networks

Kota Ando, Kodai Ueyoshi, Yuka Oba, Kazutoshi Hirose, Ryota Uematsu, Takumi Kudo, Masayuki Ikebe, Tetsuya Asai, Shinya Takamaeda-Yamazaki, Masato Motomura

Abstract: Deep neural network (NN) has been widely accepted for enabling various AI applications, however, the limitation of computational and memory resources is a major problem on mobile devices. Quantized NN with a reduced bit precision is an effective solution, which relaxes the resource requirements, but the accuracy degradation due to its numerical approximation is another problem. We propose a novel quantized NN model employing the “dithering” technique to improve the accuracy with the minimal additional hardware requirement at the view point of the hardware-algorithm co-designing. Dithering distributes the quantization error occurring at each pixel (neuron) spatially so that the total information loss of the plane would be minimized. The experiment we conducted using the software-based accuracy evaluation and FPGA-based hardware resource estimation proved the effectiveness and efficiency of the concept of an NN model with dithering.