Comprehensive Review and Comparative Analysis of Hardware Architectures for Sobel Edge Detector

Anil Kumar Saini,Sanjay Singh,Anil Vohra,Ravi Saini,Chandra Shekhar,Sumeet Saurav

doi:10.1155/2014/857912

Abstract

This paper presents a comprehensive review and a comparative study of various hardware/FPGA implementations of Sobel edge detector and explored different architectures for Sobel gradient computation unit in order to show the various trade-offs involved in choosing one over another. The different architectures using pipelining and/or parallelism (key methodologies for improving the performance/frame rates) are explored for gradient computation unit in Sobel edge detector. How the different architectures affected performance (in terms of video frame rate and image size) and area (in terms of FPGA resources usages) has been demonstrated. By exploiting the trade-offs between video frame rate, image size, and FPGA resources a designer should be able to find an optimal architecture for a given application.

Highlights

Edge detection, one of the fundamental and most important problems of lower level image processing, plays a very important role in the realization of a complete vision based understanding/monitoring system for automatic scene analysis/monitoring [1]
Very different approaches have been used in the literature for Sobel operator based edge detection algorithm. These range from use of general purpose processors or special purpose digital signal processors or graphics processing units (GPUs) using compute unified device architecture (CUDA) to application specific integrated circuits (ASICs) or applications specific instruction set processors (ASIPs) or even programmable logic devices like field programmable gate arrays (FPGAs)
We have demonstrated how the different architectures affected performance and area

Summary

Introduction

One of the fundamental and most important problems of lower level image processing, plays a very important role in the realization of a complete vision based understanding/monitoring system for automatic scene analysis/monitoring [1]. Very different approaches have been used in the literature for Sobel operator based edge detection algorithm These range from use of general purpose processors or special purpose digital signal processors or graphics processing units (GPUs) using compute unified device architecture (CUDA) to application specific integrated circuits (ASICs) or applications specific instruction set processors (ASIPs) or even programmable logic devices like field programmable gate arrays (FPGAs). FPGAs provide real-time performance, limit the extensive design work and time required for ASICs, and provide possibility to perform algorithmic changes in later stages of system development These features make FPGAs a suitable choice for implementing image processing algorithms (in particular Sobel operator based edge detection scheme). There are three important metrics for hardware/VLSI architecture when it comes to image processing application (in this case Sobel edge detector): video frame rate, frame. By exploiting the trade-offs between video frame rate, image size, and FPGA resources a designer should be able to find an optimal architecture for a given application

Sobel Edge Detection Algorithm

Literature Review

Sobel Edge Detection Architecture

Gradient Computation Unit Architectures

Results and Discussions

Conclusions