Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network

This paper presents an always-on Complementary Metal Oxide Semiconductor (CMOS) image sensor (CIS) using an analog convolutional neural network for image classification in mobile applications. To reduce the power consumption as well as the overall processing time, we propose analog convolution circu...

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Main Authors: Jaihyuk Choi, Sungjae Lee, Youngdoo Son, Soo Youn Kim
Format: Article
Language:English
Published: MDPI AG 2020-05-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/20/11/3101
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author Jaihyuk Choi
Sungjae Lee
Youngdoo Son
Soo Youn Kim
author_facet Jaihyuk Choi
Sungjae Lee
Youngdoo Son
Soo Youn Kim
author_sort Jaihyuk Choi
collection DOAJ
description This paper presents an always-on Complementary Metal Oxide Semiconductor (CMOS) image sensor (CIS) using an analog convolutional neural network for image classification in mobile applications. To reduce the power consumption as well as the overall processing time, we propose analog convolution circuits for computing convolution, max-pooling, and correlated double sampling operations without operational transconductance amplifiers. In addition, we used the voltage-mode MAX circuit for max pooling in the analog domain. After the analog convolution processing, the image data were reduced by 99.58% and were converted to digital with a 4-bit single-slope analog-to-digital converter. After the conversion, images were classified by the fully connected processor, which is traditionally performed in the digital domain. The measurement results show that we achieved an 89.33% image classification accuracy. The prototype CIS was fabricated in a 0.11 μm 1-poly 4-metal CIS process with a standard 4T-active pixel sensor. The image resolution was 160 × 120, and the total power consumption of the proposed CIS was 1.12 mW with a 3.3 V supply voltage and a maximum frame rate of 120.
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spelling doaj.art-b68254445abf4ded8dc3d0eb63cf734c2023-11-20T02:19:11ZengMDPI AGSensors1424-82202020-05-012011310110.3390/s20113101Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural NetworkJaihyuk Choi0Sungjae Lee1Youngdoo Son2Soo Youn Kim3Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, KoreaDepartment of Industrial and Systems Engineering, Dongguk University-Seoul, Seoul 04620, KoreaDepartment of Industrial and Systems Engineering, Dongguk University-Seoul, Seoul 04620, KoreaDepartment of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, KoreaThis paper presents an always-on Complementary Metal Oxide Semiconductor (CMOS) image sensor (CIS) using an analog convolutional neural network for image classification in mobile applications. To reduce the power consumption as well as the overall processing time, we propose analog convolution circuits for computing convolution, max-pooling, and correlated double sampling operations without operational transconductance amplifiers. In addition, we used the voltage-mode MAX circuit for max pooling in the analog domain. After the analog convolution processing, the image data were reduced by 99.58% and were converted to digital with a 4-bit single-slope analog-to-digital converter. After the conversion, images were classified by the fully connected processor, which is traditionally performed in the digital domain. The measurement results show that we achieved an 89.33% image classification accuracy. The prototype CIS was fabricated in a 0.11 μm 1-poly 4-metal CIS process with a standard 4T-active pixel sensor. The image resolution was 160 × 120, and the total power consumption of the proposed CIS was 1.12 mW with a 3.3 V supply voltage and a maximum frame rate of 120.https://www.mdpi.com/1424-8220/20/11/3101always-onComplementary Metal Oxide Semiconductor (CMOS) image sensorconvolutional neural networksimage classification
spellingShingle Jaihyuk Choi
Sungjae Lee
Youngdoo Son
Soo Youn Kim
Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network
Sensors
always-on
Complementary Metal Oxide Semiconductor (CMOS) image sensor
convolutional neural networks
image classification
title Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network
title_full Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network
title_fullStr Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network
title_full_unstemmed Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network
title_short Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network
title_sort design of an always on image sensor using an analog lightweight convolutional neural network
topic always-on
Complementary Metal Oxide Semiconductor (CMOS) image sensor
convolutional neural networks
image classification
url https://www.mdpi.com/1424-8220/20/11/3101
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AT sungjaelee designofanalwaysonimagesensorusingananaloglightweightconvolutionalneuralnetwork
AT youngdooson designofanalwaysonimagesensorusingananaloglightweightconvolutionalneuralnetwork
AT sooyounkim designofanalwaysonimagesensorusingananaloglightweightconvolutionalneuralnetwork