image_edge, an Octave 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 information on this web page is distributed under the MIT license.
image_edge is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version.
edge, an Octave code which defines some test functions in 1d, 2d and 3d for the detection of edges.
image_boundary, an Octave code which reports the pixels which form the boundary between the black and white regions of a simple image.
image_components, an Octave code which seeks the connected "nonzero" or "nonblack" components of an image or integer vector, array or 3d block.
image_contrast, an Octave code which applies image processing techniques to increase the contrast in an image.
image_decimate, an Octave code which compresses an image by dropping the even rows and columns of data.
image_denoise, an Octave code which applies image processing techniques to remove noise from an image.
image_diffuse, an Octave code which uses diffusion to smooth out an image.
image_double, an Octave code which doubles the height and width of an image by repeating each row and column.
image_noise, an Octave code which adds noise to an image.
image_quantization, an Octave 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, an Octave code which makes a grayscale version of an RGB image.
image_threshold, an Octave 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, an Octave 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.