"Proceedings, Federal Interagency Workshop,
"Sediment Technology for the
21'st Century,"
St. Petersburg, FL, February 17-19,
1998"
Development of an Suspended Sediment Measurement System (SSMS)
By Dan Gooding
Pre-Proposal
Issue/Problem
A device has long been sought after to measure the full spectrum of
suspended solids concentration and particle size and at the same time
endure the hostile field environment. Ideally such a device should
need little or no calibration and easily operated with limited
instructions. With the recent advancements of high-resolutions digital
cameras, PCI frame grabbers with filters, along with the increasing
computing power of PCÕs, we can capture in-stream images at a faster
rate and compute far greater amount of data for digital images as in
the past. Digital signal processing with multiple images along with an
established algorithm can instantly produce in-situ stream
concentration and complete size distribution down to 4 microns.
The technology can be used for a variety of other reasons such as the
investigation of stratified flows, sedimentation jets and plumes,
velocity measurements, flow structures, concentration measurements, and
particle size, just to name a few. For simplicity this proposal will
focus on two by-products of this device, concentration and particle
size.
Beneficiaries
Both government and private agencies interested in environmental concerns
or anyone interested with sediment transportation/movement in riverine,
estuarine, and marine ecosystems.
Objectives
There are four basic objectives for the development; 1. Minimize cost by
using much off-the-shelf instrumentation as possible; 2. Package the
technology in a way to simplify operation for the users; 3. Minimize
equipment exposure from water hazards resulting in expensive replacement
costs or repairs; The only components subject to weather and immersed in
water will be the lens, a photo-optical chip and a portion of the cable; 4.
Develop the means for remote monitoring to accomplish continuous realtime,
single point monitoring of a 24 hour period.
Approach
A two stage approach is recommended. The basic components will include
1) progressive area scanning CCD (charge coupled device) camera 3) lens
and CCD chip 4) a light source 5) PCI frame grabber and filtering
software. These are all standard pieces of hardware and can be easily
purchased commercially. The PCI frame grabber and filtering software
may only be needed for the prototype to develop an algorithm. A
prototype will be designed and tested for laboratory applications.
Incorporating this technology in the laboratory will greatly increase
the throughput. Discrete samples can be placed directly into a
cylinder or tube to give instantaneous size and concentration readings.
Not only the speed of producing results will be a benefit but also
samples will be easily analyzed in native water. After successful
evaluation as a laboratory instrument the second stage can commence
with a high degree of confidence with the development of a field
sampler.
The lens, light, and CCD chip will be assembled and installed into a
sealed canister. The canister will have the size and dimension of a
one liter sample bottle. The concept is to insert the canister into a
depth integrated sampler such as the D-77. The sampler nozzle will
line-up with the canister orifice that leads into the analyzing tube
and exits through the exhaust port of the sampler. With little or no
modification to the depth integrated sampler, the sampler will
interchangeably work with both a sample bottle or this proposed
electronic device.
Funding
Up-front funding for developing the imaging prototype for both laboratory
and field applications will be < 20k for equipment purchases.
Approximately man year is needed for development for the laboratory
version and additional man year for a field prototype.
Principal Investigator
Dan Gooding, Cascades Volcano Observatory, Vancouver, Washington
Workshop Contributions
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