IMAGE_DENOISE_OPENMP
Remove Noise from an Image

IMAGE_DENOISE_OPENMP is a C program which uses the median filter to try to remove noise from an image, using OpenMP to carry out the filtering in parallel.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

IMAGE_DENOISE_OPENMP is available in a C version.

Related Data and Programs:

DIJKSTRA_OPENMP, a C program which uses OpenMP to parallelize a simple example of Dijkstra's minimum distance algorithm for graphs.

FFT_OPENMP, a C program which demonstrates the computation of a Fast Fourier Transform in parallel, using OpenMP.

FUNCTIONS_OPENMP, a C program which demonstrates the behavior of a few of the OpenMP library functions.

HEATED_PLATE_OPENMP, a C program which solves the steady (time independent) heat equation in a 2D rectangular region, using OpenMP to run in parallel.

HELLO_OPENMP, a C program which prints out "Hello, world!" using the OpenMP parallel programming environment.

IMAGE_DENOISE, a C library which applies simple filtering techniques to remove noise from an image.

JACOBI_OPENMP, a C program which illustrates the use of the OpenMP application program interface to parallelize a Jacobi iteration solving A*x=b.

JULIA_OPENMP, a C program which produces an image of a Julia set, using OpenMP to carry out the computation in parallel.

MANDELBROT_OPENMP, a C program which generates an ASCII Portable Pixel Map (PPM) image of the Mandelbrot set, using OpenMP for parallel execution.

MD_OPENMP, a C program which carries out a molecular dynamics simulation in parallel, using OpenMP.

MULTITASK_OPENMP, a C program which demonstrates how to "multitask", that is, to execute several unrelated and distinct tasks simultaneously, using OpenMP for parallel execution.

MXM_OPENMP, a C program which computes a dense matrix product C=A*B, using OpenMP for parallel execution.

MXV_OPENMP, a C program which computes a dense matrix-vector product b=A*x, using OpenMP for parallel execution.

OPENMP, C programs which illustrate the use of OpenMP.

OPENMP_RCC, C programs which illustrate how a C program, using OpenMP, can be compiled and run in batch mode on the FSU High Performance Computing (HPC) cluster operated by the Research Computing Center (RCC).

PGMA_IO, a C library which handles the ASCII Portable Gray Map (PGM) format.

POISSON_OPENMP, a C program which computes an approximate solution to the Poisson equation in a rectangle, using the Jacobi iteration to solve the linear system, and OpenMP to carry out the Jacobi iteration in parallel.

PRIME_OPENMP, a C program which counts the number of primes between 1 and N, using OpenMP for parallel execution.

QUAD_OPENMP, a C program which approximates an integral using a quadrature rule, and carries out the computation in parallel using OpenMP.

QUAD2_OPENMP, a C program which approximates a multidimensional integral using a quadrature rule. The quadrature computation is done with OpenMP.

QUAD2D_OPENMP, a C program which estimates an integral over a 2D rectangular domain by using an averaging technique, and uses OpenMP to carry out the calculation in parallel.

RANDOM_OPENMP, a C program which illustrates how a parallel program using OpenMP can generate multiple distinct streams of random numbers.

SATISFY_OPENMP, a C program which demonstrates, for a particular circuit, an exhaustive search for solutions of the circuit satisfiability problem, using OpenMP for parallel execution.

SCHEDULE_OPENMP, a C program which demonstrates the default, static, and dynamic methods of "scheduling" loop iterations in OpenMP to avoid work imbalance.

SGEFA_OPENMP, a C program which reimplements the SGEFA/SGESL linear algebra routines from LINPACK for use with OpenMP.

SUPERLU_OPENMP, C programs which illustrate the use of the SUPERLU_OPENMP library, a version of SUPERLU compiled with the OpenMP parallel programming interface, for the fast direct solution of large sparse systems of linear equations.

ZIGGURAT_OPENMP, a C program which demonstrates how the ZIGGURAT library can be used to generate random numbers in an OpenMP parallel program.

Reference:

1. Jonas Gomes, Luiz Velho,
   Image Processing for Computer Graphics,
   Springer, 1997,
   ISBN: 0387948546,
   LC: T385.G65.
2. William Pratt,
   Digital Image Processing,
   Second Edition,
   Wiley, 1991,
   ISBN13: 978-0471857662,
   LC: TA1632.P7.

Source Code:

• image_denoise.c, the source code.
• image_denoise.h, the include file.

Examples and Tests:

• image_denoise_test.c, a sample calling program.
• image_denoise_test.txt, the output file.

BALLOONS is an RGB image of a couple with balloons, to which salt and pepper noise has been added.

• balloons_noisy.ascii.pgm, the ASCII PGM file of glassware, with added noise.
• balloons_noisy.png, a PNG version.
• balloons_median_news.ascii.ppm, the ASCII PPM file of balloons, after the noise has been filtered using the median NEWS filter.
• balloons_median_news.png, a PNG version.
• balloons_median_news2.ascii.ppm, after application 2 of MEDIAN NEWS.
• balloons_median_news2.png, a PNG version.
• balloons_median_news3.ascii.ppm, after application 3 of MEDIAN NEWS.
• balloons_median_news3.png, a PNG version.
• balloons_median_news4.ascii.ppm, after application 4 of MEDIAN NEWS. Notice that most of the remaining defects are 2x2 blocks of equal noise value, which cannot be filtered.
• balloons_median_news4.png, a PNG version.

GLASSWARE is a grayscale image of glassware, to which salt and pepper noise has been added.

• glassware_noisy.ascii.pgm, the ASCII PGM file of glassware, with added noise.
• glassware_noisy.png, a PNG version.
• glassware_mean_news.ascii.pgm, the ASCII PGM file of glassware, after the noise has been filtered using the mean NEWS filter.
• glassware_mean_news.png, a PNG version.
• glassware_median_news.ascii.pgm, the ASCII PGM file of glassware, after the noise has been filtered using the median NEWS filter.
• glassware_median_news.png, a PNG version.

List of Routines:

• GRAY_MEAN_NEWS uses a mean NEWS filter on a gray scale image to remove noise.
• GRAY_MEDIAN_NEWS uses a median NEWS filter on a gray scale image to remove noise.
• I4MAT_COPY copies one I4MAT to another.
• I4VEC_FRAC searches for the K-th smallest entry in an I4VEC.
• I4VEC_mean_i4 returns the integer mean of an I4VEC.
• I4VEC_MEDIAN returns the median of an unsorted I4VEC.
• PGMA_READ_DATA reads the data in an ASCII PGM file.
• PGMA_READ_HEADER reads the header of an ASCII PGM file.
• PGMA_WRITE writes the header and data for an ASCII PGM file.
• PGMA_WRITE_DATA writes the data for an ASCII PGM file.
• PGMA_WRITE_HEADER writes the header of an ASCII PGM file.
• PPMA_READ_DATA reads the data in an ASCII portable pixel map file.
• PPMA_READ_HEADER reads the header of an ASCII portable pixel map file.
• PPMA_WRITE writes the header and data for an ASCII portable pixel map file.
• PPMA_WRITE_DATA writes the data for an ASCII portable pixel map file.
• PPMA_WRITE_HEADER writes the header of an ASCII portable pixel map file.
• RGB_MEDIAN_NEWS uses a median NEWS filter on RGB data to remove noise.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C source codes.