Convert to Greyscale

Pseudocode

PROCEDURE greyscale(image)
    FOR x = 0 .. width DO
        FOR y = 0 .. height DO
            c <- pixel(x, y)
            c' <- avg(c)
            pixel(x, y) <- c'
        END FOR
    END FOR
END PROCEDURE

Description

Loop through all pixels in the image, calculate the average (mean) value for that pixel then set the pixel values for all channels to be the calculated value.

There are many ways to calculate what this new value should be, any value where all the channels are the same value will create a black and white image.

Average Value

One of the simplest to implement is averaging the value of the pixel:

\[v = \frac{\sum_iP_i}{N}\]

Where:

v: final (new) pixel value
p: vector containing N channels
N: number of channels

Related Concepts

Calculating Averages

Acknowledgements

Adapted from Pseudocode produced for COMP120 by Dr. Micheal Scott.