Intensitetsprofilen

Intensitetsprofilen, eller intensity profile, describes how light intensity varies across space. It can be one-dimensional, such as a line cut through an image, or two-dimensional, such as a radial or azimuthal profile around a source. The concept is central to imaging sciences, including optics, astronomy, and microscopy, where the brightness distribution of a source or field carries information about structure, composition, or observational conditions.

Measurement and processing of an intensity profile involve calibrating the image and extracting intensity values along a chosen path or within defined regions. Typical steps include bias and dark correction, flat-fielding, background subtraction, and photometric calibration. Line profiles are obtained by sampling along a line, while radial profiles are built by averaging the intensity in concentric annuli around a center. The profile is often affected by the point spread function (PSF) of the imaging system and by noise, requiring careful handling to obtain a reliable representation of the intrinsic distribution.

Common models used to describe profiles include Gaussian, Lorentzian, exponential, and Moffat functions for PSFs and line-spread profiles. In astronomy, the radial brightness distribution of galaxies is frequently modeled with the Sersic profile, with the de Vaucouleurs law as a special case. In optics and microscopy, the PSF is often approximated by a Gaussian or Moffat form, reflecting optical resolution and seeing conditions.

Applications of intensity profiles include quantitative photometry, morphological classification, deconvolution to recover intrinsic structures, and cross-instrument comparisons. Limitations arise from noise, background fluctuations, sampling, and the PSF, which must be accounted for to interpret the profile accurately.