International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 01 | Jan-2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 912
Hardware Co-Simulation of Classical Edge Detection Algorithms
Using Xilinx System Generator
Avinash G. Mahalle
1
, A. M. Shah
2
1
M.Tech, Dept. of Electronics Engineering, GCOEA, Maharashtra, India
2
Assistant Professor, Dept. of Electronics Engineering, GCOEA, Maharashtra, India
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Abstract - Edge Detection is one of the most important and
fundamental processes in the field of Image Processing and
Computer Vision. It is a process of localizing pixel intensity
changes. Classical edge detection methods such as Robert,
Prewitt and Sobel are simple to design than Laplacian based
methods. Hence, these are used in Real Time image processing
applications quiet more often. The proposed designs for
Classical Operators utilize minimum resources. At the same
time, it also enhances maximum frequency of operation.
Spartan-3E Starter Kit is used for prototyping purpose. JTAG
Hardware Co-Simulation utilizes hardware in loop approach.
An efficient way to implement image processing tools on
reconfigurable hardware is to design algorithms using Xilinx
System Generator.
Key Words: Image Processing; Edge Detection; Xilinx
System Generator; JTAG Hardware Co-simulation;
Spartan-3E FPGA
1. INTRODUCTION
Digital Image consists of various pixels. Very few of these
pixels actually carry information. By detecting edges in an
image, one can preserve useful structural information and
eliminate redundant data [1]. It is an efficient way for
storage and bandwidth utilization. Edges can be
characterized by sudden change in the pixel intensity. Thus,
edges are components with high spatial frequencies. Any
change can be located by mathematical tool named as
derivative. In discrete domain, derivative is nothing but
difference equations. By convolving image pixels with given
masks this change can be located. Finding gradient implies
taking derivative for one time whereas, for finding Laplacian
derivative is taken two times. Edge profile can be
categorized as step, ramp, ridge and roof. Gradient based
methods find out maximum/minimum values whereas,
Laplacian based methods find out zero crossing [2]. Gradient
works well when image contains sharp intensity and low
noise. Hardware implementation of these edge detection
algorithms is essential in order to use it in real time [3]. Field
Programmable Gate Array (FPGA) has advantages over
Application Specific Integrated Circuit (ASIC) with no non-
recurring expense (NRE), less time to market and high
flexibility. A low cost Spartan-3E Starter Kit is used as a
hardware platform for implementation. In hardware co-
simulation approach normal Simulink blocks are executed in
MATLAB environment that generates desired operation
while JTAG simulation block loads bit stream file generated
(*.bit) in FPGA using Hardware in loop [4]. Writing code in
Hardware Description Languages (HDL) along with its test
bench programming is very tedious job. Xilinx System
Generator provides an efficient way to program FPGA by
designing algorithm using blocks [5]. Using various
compilation, HDL code and required Test bench are
generated automatically along with various parameters such
as minimum period, maximum frequency, power dissipation
and resource utilization [6].
2. EDGE DETECTION ALGORITHMS
Edge Detection algorithms are broadly classified as follow:
-First Order Derivative Methods [Gradient Based]
Robert Operator
Prewitt Operator Classical Operators
Sobel Operator
-Second Order Derivative Methods [Laplacian Based]
Marr-Hildreth Edge Detector [LoG]
-Optimal Edge Detectors: Canny Algorithm
Classical operators include Robert, Prewitt and Sobel
operators. Main advantage of these operators is that they are
simple to design and have very low latency. These are also
less susceptible to noise than Laplacian based methods.
Gradient can be find out by convolving operator mask with
image pixels. Masks are of different dimensions.
Fig -1: Horizontal & Vertical Masks for Classical Operators
Robert operator is having [2×2] mask whereas, Prewitt and
Sobel have [3×3] mask. The Fig- 1 shows both horizontal and
vertical masks for all classical operators.