IMAGE_RGB_TO_GRAY is a MATLAB function which creates a grayscale version of an RGB image.
An RGB image is an (M,N,3) array.
A grayscale image is an (M,N) array.
A grayscale version of an RGB image can be made by averaging the RGB components of each pixel.
A more sophisticated approach uses the luminance function:
GRAY = 0.2126 * R + 0.7152 * G + 0.0722 * Bwhich attempts to better model the contributions to brightness of the different colors.
function gray = rgb_to_gray ( rgb, equal )where
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
IMAGE_RGB_TO_GRAY is available in a MATLAB version.
IMAGE_CONTRAST, a MATLAB program which applies image processing techniques to increase the contrast in an image.
IMAGE_DECIMATE, a MATLAB library which compresses an image by dropping the even rows and columns of data.
IMAGE_DENOISE, a MATLAB program which applies image processing techniques to remove noise from an image.
IMAGE_DOUBLE, a MATLAB library which doubles the height and width of an image by repeating each row and column.
IMAGE_EDGE, a MATLAB program which demonstrates a simple technique for edge detection in an image.
IMAGE_MATCH_GENETIC, a MATLAB program which tries to match a 256x256 JPEG image by blending 32 colored rectangles, using ideas from genetic algorithms, based on an example by Nick Berry.
IMAGE_NOISE, MATLAB programs which add noise to an image.
IMAGE_QUANTIZATION, a MATLAB library which demonstrates how the KMEANS algorithm can be used to reduce the number of colors or shades of gray in an image.
IMAGE_THRESHOLD, a MATLAB library which creates a black and white version of a grayscale image by specifying a single threshold value; pixels below this value become black, and above this value they are white.
MathWorks documentation for the Image Processing Toolbox is available at http://www.mathworks.com/access/helpdesk/help/pdf_doc/images/images_tb.pdf.
CONJUNCTION is an astronomical image.
STAR_FIELD is an astronomical image.
You can go up one level to the MATLAB source codes.