Image Quality, General

Synonyms

Optical quality; Retinal image quality

Definition

The fidelity at which an optical system creates an image of an object. Although the term “optical quality” is used synonymously from time to time, the latter may also include aspects of subjective perception.

Basic Characteristics

Most optical systems are designed to obtain an image that represents the object imaged by the system as exactly as possible. The exactness of imaging and therefore the image quality are affected by the optical phenomena aberrations, scatter, and diffraction. For measurement, image quality is quantified with reference to the object imaged. Therefore, many image quality metrics are ratios between the characteristics of the actual image and the object. Typical characteristics quantified by metrics are the compactness of the point spread function, the loss of contrast through the optical system, and the unevenness of the wave frontcreated by the optical system. The image quality of eyes is often...