Miniaturized digital inline holographic camera for in-situ plankton detection

Abstract

Aiming at being carried on various underwater vehicles for the detection of plankton, a miniaturized in-situ digital inline holographic system named OUC-HoloCam²⁰⁰ is designed and developed. Although the structure of OUC-HoloCam²⁰⁰ is simple and compact, the system performance is still excellent. Tests have been carried out and the result shows that the optical resolution of OUC-HoloCam²⁰⁰ is 8.77 μm, the depth of field is up to 30 cm, the field of view is 8.44×6.75 mm² , which means theoretically with each exposure, about 300 mL of seawater can be investigated. OUC-HoloCam²⁰⁰ have been deployed in the nearshore area of the South China Sea and have worked continuously over 48 hours, after holographic reproduction and image processing the data is able to show the trends of changing in number and species of plankton over time in the same location.