Quantization, in mathematics and
digital signal processing, is the process of mapping a large set of input values to a (countable) smaller set.
Rounding and
truncation are typical examples of quantization processes. Quantization is involved to some degree in nearly all digital signal processing, as the process of representing a signal in digital form ordinarily involves rounding. Quantization also forms the core of essentially all
lossy compression algorithms. The difference between an input value and its quantized value (such as
round-off error) is referred to as
quantization error. A device or
algorithmic function that performs quantization is called a
quantizer. An
analog-to-digital converter is an example of a quantizer.