A typical use of dither is converting a greyscale image to black and white, such that the density of black dots in the new image approximates the average grey level in the original. Engineers realized that the steps in digital image processing pdf from the aircraft reduced the error from sticky moving parts.
Instead of moving in short jerks, they moved more continuously. Small vibrating motors were built into the computers, and their vibration was called dither from the Middle English verb “didderen,” meaning “to tremble. Today, when you tap a mechanical meter to increase its accuracy, you are applying dither, and modern dictionaries define dither as a highly nervous, confused, or agitated state. In minute quantities, dither successfully makes a digitization system a little more analog in the good sense of the word. By 1964 dither was being used in the modern sense described in this article. Dither is often used in digital audio and video processing. It is utilized in many different fields where digital processing and analysis are used.
In some fields, especially where the receptor is sensitive to such artifacts, cyclical errors yield undesirable artifacts. In these fields introducing dither results in less determinable artifacts. The field of audio is a primary example of this. Random noise is typically less objectionable than the harmonic tones produced by limit cycles. Each coded value is a discrete step if a signal is quantized without using dither, there will be quantization distortion related to the original input signal In order to prevent this, the signal is “dithered”, a process that mathematically removes the harmonics or other highly undesirable distortions entirely, and that replaces it with a constant, fixed noise level.