nj-hevc/edges

Implementation of some classical edge detection algorithms; Roberts, Prewitt, Sobel, Haralick and Marr-Hildreth.

REVIEW OF EDGE DETECTORS - IPOL 2012

About

These are the source files implementing some classical algorithms of edge detection.

The implemented algorithms are:

• First Derivative:
• Roberts
• Prewitt
• Sobel
• Second Derivative:
• Marr-Hildreth
• Haralick

The algorithms are implemented in C language and are compiled using cmake.

Filelist

Root directory:

.:
@build          - Suggested compilation directory.
@build/bin  	 -	Binary files folder (empty until compilation).
CMakeLists.txt  -	CMake configuration file.
README  		- 	This file.
src  			-	Source files folder.
test			-	Test images folder.

./@build/bin: (empty until compilation)

./example:

lena_harlick.png	-	Output of Haralick algorithm using lena.png as input image.
lena_mh.png			-	Output of Marr-Hildreth algorithm (Gaussian kernel) using lena.png as input image.
lena_mhlog.png		-	Output of Marr-Hildreth algorithm (LoG kernel) using lena.png as input image.
lena_prewitt.png	-	Output of Prewitt algorithm using lena.png as input image.
lena_roberts.png	-	Output of Roberts algorithm using lena.png as input image.
lena_sobel.png		-	Output of Sobel algorithm using lena.png as input image.

./src:

2dconvolution.c  	-	Implementation of the 2-D convolution.
2dconvolution.h		-	(header file).
CMakeLists.txt		-	CMake configuration file.
gaussian_kernel.c	-	Implementation of the Gaussian and LoG kernel generation.
gaussian_kernel.h	-	(header file).
iio.c 				-	IIO library C-file.
iio.h     			-	IIO library (header file).
test_fded.c      	-	First derivative edge detectors, main C file.
test_haralick.c		-	Haralick algorithm, main C file.
test_mh.c   		-	Marr-Hildreth algorithm (Gaussian kernel), main C-file.
test_mh_log.c 		-	Marr-Hildreth algorithm (LoG kernel), main C-file.

./test:

lena_gray.png  	-	Lena image (512x512px).
molino_gray.png   -	Windmill image (1000x563px).
oranges_gray.png	-	Oranges image (536x480px).

Compilation

In the @build directory:

> cmake ..
> make

An executable file is created in the @build/bin directory:

bin/:
edges_ipol
test_fded  		-	First derivative edge detectors (Roberts, Prewitt & Sobel).
test_haralick  	-	Haralick algorithm.
test_mh  		-	Marr-Hildreth algorithm, using Gaussian kernel.
test_mh_log		-	Marr-Hildreth algorithm, using LoG kernel.

Execution

First derivative edge detectors:

Usage:

> test_fded input_image threshold

Example:

> bin/test_fded test/lena.png 0.1
Input image loaded:	 512x512 image with 3 channel(s).
images converted to grayscale
Roberts image saved to roberts.png.
Prewitt image saved to prewitt.png.
Sobel image saved to sobel.png.
Edge detection algorithms based on first derivative computation done.
execution time: 0.280 s.

Haralick algorithm:

Usage:

> test_haralick input_image rhozero output

Example:

> bin/test_haralick test/lena.png 0.5 lena_harlick.png
Input image loaded:	 512x512 image with 3 channel(s).
images converted to grayscale
60122 edge points found...
Output Image saved in lena_harlick.png:	 512x512 image with 3 channel(s).
haralick's edge detector computation done.
execution time: 0.440 s.

Marr-Hildreth algorithm (Gaussian Kernel):

Usage:

> test_mh input_image sigma n tzc output_image

Example:

> bin/test_mh test/lena.png 2 13 0.1 lena_mh.png
Input image loaded:	 512x512 image with 3 channel(s).
images converted to grayscale
Output Image saved in lena_mh.png:	 512x512 image with 3 channel(s).
marr-hildreth edge detector computation done.
execution time: 0.420 s.

Marr-Hildreth algorithm (LoG kernel):

Usage:

> test_mh_log input_image_1 sigma n tzc output

Example:

> bin/test_mh_log test/lena.png 2 17 0.1 lena_mhlog.png
Input image loaded:	 512x512 image with 3 channel(s).
images converted to grayscale
Output Image saved in lena_mhlog.png:	 512x512 image with 3 channel(s).
marr-hildreth edge detector computation done.
execution time: 0.670 s.

Test images

Some test images are provided in the «test» folder. The output images using «lena.png» as input image, are also provided in the «example» directory.

Tested platforms

• Ubuntu Linux 14.04 x86_64
  • gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
• OSX Mavericks 10.9.2
  • clang

Changelog

• 2014.04.30:
  • Improved documentation to reflect the new implementation executables

Copyrights

Copyright (C) 2011-2012, Haldo Spontón [email protected]

Copyright (C) 2011-2012, Juan Cardelino [email protected]

License

This program is free software: you can use, modify and/or redistribute it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. You should have received a copy of this license along this program. If not, see http://www.gnu.org/licenses/.

This program is free software: you can use, modify and/or redistribute it under the terms of the simplified BSD License. You should have received a copy of this license along this program. If not, see http://www.opensource.org/licenses/bsd-license.html.

This program is provided for research and education only: you can use and/or modify it for these purposes, but you are not allowed to redistribute this work or derivative works in source or executable form. A license must be obtained from the patent right holders for any other use.