What is blue noise?
Blue noise increases in volume with increasing frequency, but at a slower rate than a similar type of noise called purple noise. Blue noise is also known as azure noise.
Blue noise is one of many expressions for different types of noise that work differently in the noise frequency spectrum. Blue noise is characterized as noise with a less pronounced increase in frequency than purple noise. It can also be contrasted with pink noise, with the intensity decreasing by a similar range over a finite frequency range. This relative increase and decrease is 3 decibels per octave.
In terms of its uses, blue noise is sometimes used for randomization or pattern projection, such as in digital images that use or override gray levels. For example, a dithering strategy is used in audio and video processes to project various changes to images. Blue noise can be useful in dithering because of its logarithmic function.