Image enhancement aims to optimize visual effects. According to practical application scenarios, it selectively improves overall or local image features, sharpens blurred pictures and highlights target characteristics. It enlarges the distinction between different objects and suppresses irrelevant details, so as to upgrade image quality, enrich information content, optimize interpretation and recognition performance, and meet the demands of feature analysis.

Common image enhancement methods: linear transformation, nonlinear transformation, histogram equalization and histogram specification.