LISST HOLO2

SUBMERSIBLE DIGITAL HOLOGRAPHIC CAMERA

• Particle Images

• Particle Size Distribution

• Particle Volume Concentration

The LISST-Holo2 is a submersible digital holographic camera. It is designed for capturing holograms of suspended particles (algae, plankton, sediment, oil droplets, flocs etc.). The internal rechargeable battery and memory allow for collection of up to 100,000 holograms. To facilitate data processing, the included software ranks the holograms by image content richness, then automatically extracts particle information and images from the holograms.

The resulting data output is a composite image where all particles are in focus, as well as the particle size distribution and volume concentration.

FEATURES

• In-situ digital in-line holographic technology

• Self-contained with internal datalogger and rechargeable battery

• Ethernet connection to PC for programmable data collection—no software needed for programming or offloading data

• Power via internal rechargeable battery pack or external power source

• Programmable data collection including burst and fixed Rate modes and programmable start and stop conditions

• Automated firmware updates possible when instrument is connected to the Internet

• Automated ranking of collected images based on richness of data, permitting a user to view the most interesting holograms first

• Data processing yields in-focus particle images and particle volume distribution

• Optical Path Reduction Modules available for higher concentration ranges

• Towable up to 4 knots (2.05 m∙s-1).

Specifications

(Specifications are subject to change)

Parameters Measured

2MB Hologram containing the interference pattern of all particles in the laser beam

Depth

Temperature

Time-stamp on each hologram

Parameters derived upon hologram processing

Reconstructed in-focus images of particles in laser beam.

Particle Size Distribution (PSD)

Standard Deviation of PSD

Particle Area Concentration

Mean and Median particle size

5 seconds processing time per 1 cm 3 volume imaged, in MATLAB (typical, @ 2.2 GHz PC)

Particle Size Distribution and concentration range

~25-2500µm size range

Beam attenuation values between 0 and 4 m-1

Maximum concentration between 0 and 50 mg/l, depending on grain size. 

Technology

Solid state laser diode @ 658 nm, 8 mW

4.4µm pixel size digital camera, 1600 x 1200 pixels

2 MB hologram size

Hologram capture rate programmable up to 20 Hz continuous;

Optical path length 50 mm standard; Path reduction modules available for high-concentration environments.

All particles in focus in optical path.

Sampling volume per hologram 1.5 cm 3

Volume sampled per second at 20Hz sample rate: 30 cm 3

Maximum current velocity/CTD speed during deployment: 2 m s -1 

Software

Holo Batch: Automated image reconstruction and particle segmentation

Holo Detail: Hologram sorting by richness of information content, and detailed reconstructed image examination.

Mechanical and Electrical

Dimensions: 13.3 cm × 76.7 cm (5.25″ × 30.21″) [Ø × L]

Weight: 7.2 kg (15.8 lbs) in air; 1.0 kg (2.2 lbs) in water

600 m depth rating

237 GB internal solid state drive

Internal Battery life: at least 12 hours of continuous use.

External power input: 18VDC nominal, 12-24VDC

Power drain: 200µA / 700mA / 800mA / 800mA (sleeping / idling / laser on / laser + camera on)