image_edge, a MATLAB code which demonstrates the detection of edges in an image.
NEWS is a particularly simple edge detection scheme, which compares the North, East, West, and South neighbors of a pixel to determine if the pixel lies along an edge.
There are many sophisticated edge detection algorithms, and MATLAB has many of them built into its image processing toolbox. The purpose of these examples is simply to demonstrate how a simple version of such edge detection schemes works.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
image_edge is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
edge, a MATLAB code which defines some test functions in 1d, 2d and 3d for the detection of edges.
image_boundary, a MATLAB code which reports the pixels which form the boundary between the black and white regions of a simple image.
image_components, a MATLAB code which seeks the connected "nonzero" or "nonblack" components of an image or integer vector, array or 3d block.
image_contrast, a MATLAB code which applies image processing techniques to increase the contrast in an image.
image_decimate, a MATLAB code which compresses an image by dropping the even rows and columns of data.
image_denoise, a MATLAB code which applies image processing techniques to remove noise from an image.
image_diffuse, a MATLAB code which uses diffusion to smooth out an image.
image_double, a MATLAB code which doubles the height and width of an image by repeating each row and column.
image_noise, MATLAB codes which add noise to an image.
image_quantization, a MATLAB code which demonstrates how the kmeans algorithm can be used to reduce the number of colors or shades of gray in an image.
image_rgb_to_gray, MATLAB codes which makes a grayscale version of an rgb image.
image_threshold, a MATLAB code which makes a black and white version of a grayscale image by setting all pixels below or above a threshold value to black or white.
pgma_io, a MATLAB code which handles the ascii portable gray map (pgm) format.
MathWorks documentation for the Image Processing Toolbox is available at https://www.mathworks.com/access/helpdesk/help/pdf_doc/images/images_tb.pdf.