In Situ Underwater Electronic Holographic Camera for Studies of Plankton

Hongyue Sun, David Cyril Hendry, Michael Antony Player, John Watson

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

In this paper, we describe an underwater electronic holographic camera (eHoloCam) that has been developed for in situ studies of the distribution and dynamics of plankton and other marine organisms and particles. The eHoloCam uses an Nd-YAG pulsed laser to freeze-frame fast moving particles and a complementary metal-oxide-semiconductor (CMOS) sensor for high-resolution image capture. Digital holograms and holographic videos are recorded at rates from 5 to 25 Hz over a period of several hours. Data is stored locally on an embedded computer. The eHoloCam is capable of recording all organisms and particles located in a water volume of 36.8 cm3 in a single hologram frame. The recorded holographic videos may subsequently be reconstructed numerically at a desired image plane. The main optical and mechanical specifications for eHoloCam are also described. To record electronic holographic videos of marine organisms, the eHoloCam was deployed from a towed sampling frame [autorecording instrumented environmental sampler (ARIES)] on the research vessel RV Scotia at speeds up to 4 kn (about 2 mldrs-1) in the North Sea off the Shetland Isles. Various images of marine organisms obtained from this deployment are shown, together with preliminary measurements on the distribution of Calanus copepods.
Original languageEnglish
Pages (from-to)373-382
Number of pages10
JournalIEEE Journal of Oceanic Engineering
Volume32
Issue number2
DOIs
Publication statusPublished - Apr 2007

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Keywords

  • holography
  • microorganism
  • optical imaging
  • underwater technology

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