Variability of the Point Spread Function in the water column

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


The Point Spread Function (PSF) is an important property in predicting beam propagation and imaging system performance. An instrument to measure the in situ PSF of ocean water has been built and PSF profiles obtained. This instrument consists of two parts, a flashlamp with cosine emission characteristics, and an imaging solid state camara system. The camera system includes a thermoelectrically cooled CCD array with over 50 dB of dynamic range. This allows the camera to measure the steeply peaked PSF over short (10m) to (80 m) ranges. Measurements of the PSF in three different locations are presented. One location was a coastal station off San Diego where the water column exhibited a well defined shallow (approximately 30 meter) mixed layer with a particulate maximum (defined by a maximum in beam attenuation) at the bottom of this layer. During these measurements the PSF was highly variable with depth, as was to be expected due to the dependence of the PSF on particle concentration and size distribution. In the second example the water column was almost homogeneous (as evidenced in the beam attenuation profiles). Hence, the PSF showed very little dependence on depth. Measurements of the variation of the PSF with range are also presented. A simple relationship of the variation of the PSF with angle and optical path length is presented.

Original languageEnglish (US)
Pages (from-to)355-362
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1990
EventOcean Optics X - Orlando, FL, USA
Duration: Apr 16 1990Apr 18 1990

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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