MAE 156B Snow Cam Project


Executive Summary here

Background

            Jules Jaffe's Laboratory for Underwater Imaging has been working on creating imaging systems for measuring particle size and abundance. As of recently, the Underwater imaging group has been interested in successfully measuring the descent rate of marine snow.  Marine snow is a continuous shower of organic material that plays an important role in carbon transportation.  Nearly all carbon that is permanently removed from the ocean results from sinking organic material, and the ocean’s biological pump is responsible for this. 

As the Earth's climate changes due to natural or man-made processes, it is important to understand the biological and ecological processes impact of the carbon cycle within the ocean.  Snow-Cam was designed to autonomously take pictures of the marine snow as it slowly descends without disturbing the natural environment.  This device is used as a prototype to estimate the rate of marine snow export in depths less than 200 m.  Jaffe will be using the results from Snow-Cam in a project proposal as a proof of concept.

A proven device would lead to further study of oceanic snow processes. A lightweight, simple and inexpensive design would lead to the development of many snow measuring devices. A fleet of Snow-Cams would be needed to effectively sample snowfall rates at various locations throughout the globe. Statistically significant snowfall data would lead to an estimation to the amount of CO2 being absorbed by the oceans.


Objective

 

    The snow-cam was designed to analyze the approximate flux of snow particles within a control volume. This device shall be a prototype developed for the purpose of determining a proof of concept for future proposals for the Scripps Institute of Oceanography.

    As the snow-cam descends into the ocean, it will take pictures of ocean snow particles that reside within a control volume over time. An array of vertically aligned cameras in a submersible tube will descend at a constant rate. As the snow-cam sinks, it will take multiple pictures to determine the relative descent rate of the particles. An array of sensors will be coupled with the image data which will then be collected and stored digitally for later use with image processing and analysis.

 







Description
 
    What's the Snow-Cam?
        The Snow-Cam is a hydro-dynamic submersible device used for the imaging and analysis of marine snow particles.

    How is it made?
        It is comprised of two slender cylinders which contain a camera array and a lighting array. Sensors are also equipped throughout the device to monitor pressure, temperature,                    humidity, tilt, rotation and accelerations. A power management system is also utilized to power all the components.

    Key Features
  •         GoPro Cameras:
                            5 GoPro Hero Naked HD cameras spaced evenly apart. Equipped with custom lenses with a 19deg field of view. Images captured via a trigger from the microprocessor.
  •         Sensors and Microprocessor: 
                            Arduino Uno microprocessor triggers cameras, lights and stores data from a variety of sensors.
                            P51 Pressure Transmitter
                            Honewell Compass with tilt compensation
                            Parallax Temperature/Humidity sensor
  •         Lighting:
                            5 LEDeng LEDs coupled with a 18deg focusing lens triggered by microprocessor
  •         Pressure Vessel:
                            2 Delrin end caps attached, via a double bore seal, to a cast acrylic tube
  •         Interior:
                            Three aluminum rods with acrylic discs spaced with plastic tubes are combined together to create a rigid structure for the mounting of all electronics and components 
  •         Exterior:
                            Elliptically shaped hydrodynamic aluminum nose cone is threaded into end cap
                            Cast acrylic cylinders for cameras to view through and provide structural integrity
                            Cylinder Clamps grip on to both housings and are attached via a strut channel