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Contents
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| Functional Description | Specifications | |
| Development Pictures/Movies/Data | Cruises | |
Functional Description
LUMIS is based upon a Photometrics camera that utilizes a 1024x1024 pixel, liquid-cooled CCD chip with 14 bit resolution. Unlike more conventional, non-scientific cameras, this device has the advantage of being radiometrically calibrated.
A custom four-lens fiber optic assembly interfaces with the chip. Input from each of the lenses is mapped to a specific quadrant on the CCD chip via fiber optic waveguides. Multispectral images may be acquired by placing a different filter in front of each lens.
In addition, the high sensitivity (10-4 lux) of this camera makes it ideal for capturing fluorescence events and its four spectral channels permit simultaneous recording at different wavelengths. To our knowledge this unique camera system is the only underwater, low-light level, multispectral instrument in existence.
Our primary applications for LUMIS are in situ studies of (1) phytoplankton taxa and spatial variations; and (2) coral fluorescent pigment distributions. We have conducted plankton-related experiments in oligotrophic (Gulf of Eilat, Red Sea), eutrophic (Saanich Inlet, B.C., Canada), and coastal (coast off San Diego, California) waters. In these experiments, a 60 cm x 60 cm x 0.75 cm volume was illuminated by a laser through a fiber optic cable, yielding a sampled volume of about 3 L. Preliminary analysis indicates that the data contain information about phytoplankton patchiness. In addition, the multispectral property of the data provides insight into the spatial variation of blue-green algae with respect to green algae. To date, we have only conducted coral experiments in exhibit tanks (Scripps Aquarium). The sample images indicate strong chlorophyll fluorescence (680 nm band) and weaker levels of fluorescence in the other bands.
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Camera
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| Make & Model | Photometrics AT200 | |
| CCD | Thomson TH7896A, 1024 x 1024 pixels | |
| Pixel size | 19 x 19 µm | |
| Resolution | 14 bits @ 200 kHz | |
| Sensitivity | 10-4 lux | |
| Gray levels | 16384 max | |
| Lenses | Standard closed-circuit TV (1" format CCTV) | |
| Shutters | mechanical, one for each lens | |
| Min exposure | milliseconds | |
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Illumination Sources
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| Nd:YAG pulsed laser | 532 nm | |
| Argon Ion CW laser | Major lines at 514 and 488 nm | |
| Normark Norlite 400 Strobe | Xenon bulb, 400 Watt-secs | |
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Physical Aspects
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| Housing dimensions | 107 cm long, 33 cm diameter | |
| Weight (in air) | ~ 68 kg | |
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Operation
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| Camera is remotely operated; a 100 m umbilical connects it to the computer | ||
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Pictures
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Housing and frame |
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Viewports |
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Internal components |
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Data
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Raw uncorrected data from chlorophyll maximum in oligotrophic waters in the Gulf of Eilat 1997. |
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Raw uncorrected data from chlorophyll maximum in eutrophic waters in Saanich Inlet 1997. |
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Raw uncorrected data from San Diego coastal waters 1997 chlorophyll concentrations around 0.2 ug/L |
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LUMIS SIO Aquarium Test: Pacific Corals - Favia spp. & Porites spp. LUMIS-to-coral distance = 1m; strobe-to-coral distance = 0.5m; FOV Å 9 x 9 inches each quadrant Data represent RAW, uncorrected fluorescence values. Resolution = 1024 x 1024; Exposure = 10 ms. |
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Gulf of Eilat, Red Sea, May 1997 |
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Saanich Inlet, B.C., Canada, August 1997 |
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Coast off San Diego, California, November 1997 |
| National Science Foundation |
