Neural network-based vehicle image classification for IoT devices

Convolutional Neural Networks (CNNs) have previously provided unforeseen results in automatic image analysis and interpretation, an area which has numerous applications in both consumer electronics and industry. However, the signal processing related to CNNs is computationally very demanding, which has prohibited their use in the smallest embedded computing platforms, to which many Internet of Things (IoT) devices belong. Fortunately, in the recent years researchers have developed many approaches for optimizing the performance and for shrinking the memory footprint of CNNs. This paper presents a neuralnetwork-based image classifier that has been trained to classify vehicle images into four different classes. The neural network is optimized by a technique called binarization, and the resulting binarized network is placed to an IoT-class processor core for execution. Binarization reduces the memory footprint of the CNN by around 95% and increases performance by more than 6×. Furthermore, we show that by utilizing a custom instruction 'popcount' of the processor, the performance of the binarized vehicle classifier can still be increased by more than 2×, making the CNN-based image classifier suitable for the smallest embedded processors.©2029 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed

GPU-based Architecture Modeling and Instruction Set Extension for Signal Processing Applications

The modeling of embedded systems attempts to estimate the performance and costs prior to the implementation. The early stage predictions for performance and power dissipation reduces the more costly late stage design modifications. Workload modeling is an approach where an abstract application is evaluated against an abstract architecture. The challenge in modeling is the balance between fidelity and simplicity, where fidelity refers to the correctness of the predictions and the simplicity relates to the simulation time of the model and its ease of comprehension for the developer. A model named GSLA for performance and power modeling is presented, which extends existing architecture modeling by including GPUs as parallel processing elements. The performance model showed an average fidelity of 93% and the power model demonstrated an average fidelity of 84% between the models and several application measurements. The GSLA model is very simple: only 2 parameters that can be obtained by automated scripts. Besides the modeling, this thesis addresses lower level signal processing system improvements by proposing Instruction Set Architecture (ISA) extensions for RISC-V processors. A vehicle classifier neural network model was used as a case study, in which the benefit of Bit Manipulation Instructions (BMI) is shown. The result is a new PopCount instruction extension that is verified in ETISS simulator. The PopCount extension of RISC-V ISA showed a performance improvement of more than double for the vehicle classifier application. In addition, the design flow for adding a new instruction extension for a re-configurable platform is presented. The GPU modeling and the RISC-V ISA extension added new features to the state of the art. They improve the modeling features as well as reduce the execution costs in signal processing platforms

On Design and Optimization of Convolutional Neural Network for Embedded Systems

This work presents the research on optimizing neural networks and deploying them for real-time practical applications. We analyze different optimization methods, namely binarization, separable convolution and pruning. We implement each method for the application of vehicle classification and we empirically evaluate and analyze the results. The objective is to make large neural networks suitable for real-time applications by reducing the computation requirements through these optimization approaches. The data set is of vehicles from 4 classes of vehicle types, and a convolutional model was used to solve the problem initially. Our results show that these optimization methods offer many performance benefits in this application in terms of reduced execution time (by up to 5 ×), reduced model storage requirements, with out largely impacting accuracy, making them a suitable tool for use in streamlining heavy neural networks to be used on resource-constrained envrionments. The platforms used in the research are a desktop platform, and two embedded platforms