title: RADIANCE AND PHOTON NOISE: Imaging in geometrical optics, physical optics, quantum optics and radiology.
abstract: A fundamental way of describing a photon-limited imaging system is in terms of a Poisson random process in spatial, angular and wavelength variables. The mean of this random process is the spectral radiance. The principle of conservation of radiance then allows a full characterization of the noise in the image (conditional on viewing a specified object). To elucidate these connections, we first review the definitions and basic properties of radiance as defined in terms of geometrical optics, radiology, physical optics and quantum optics. The propagation and conservation laws for radiance in each of these domains are reviewed. Then we distinguish four categories of imaging detectors that all respond in some way to the incident radiance, including the new category of photon-processing detectors. The relation between the radiance and the statistical properties of the detector output is discussed and related to task-based measures of image quality and the information content of a single detected photon.
authors.affiliation: College of Optical Sciences, University of Arizona, Tucson AZ 85721; Center for Gamma-Ray Imaging, Dept. of Medical Imaging, Tucson AZ 85724.
authors.forename: Harrison H
authors.initials: HH
authors.lastname: Barrett
authors.affiliation: Div. of Imaging and Applied Mathematics, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993.
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Myers
authors.affiliation: Center for Gamma-Ray Imaging, Dept. of Medical Imaging, Tucson AZ 85724.
authors.forename: Luca
authors.initials: L
authors.lastname: Caucci
keywords: Radiance; geometrical optics; image quality; physical optics; point processes; quantum imaging; radiology