Christian Sets up Server

Christian and I had a good day at NCSU today!

Christian really did all the work, as you can see:

Without going into details (many of which I don't understand), Christian set up this computer in the lab so we can access it remotely. Ken will be able to view images, etc, that appear on this computer while sitting at home.

While we have the computer and basic configuration in place, Christian has a good bit of detail work to finish. That's the cool part about remote access; he can work on it from home now!

The camera is the next major piece of hardware to put in place.

Water Level Measurement Software

Ken has created this interface for managing images. He says there's a lot more work to do on the software infrastructure to support this, but it's always nice to see the tangible parts!

Hydrometry - Pressure Transducers

Quite a few days have passed since my last post about water level instrumentation, so I should probably mention my source again. Hyrdrometry, 3rd Edition, by Wubbo Boiten. (You can go read the archives if you want an official MLA style citation.) All of the pressure transducer material is based on pages 8-9.

Pressure Transducers:

Three other names commonly used for pressure transducers:
- Pressure Sensors
- Pressure Probes
- Pressure Transmitters

Function:
The basic function of a pressure transducer is to take pressure and turn it into an electric signal. The electric signal is processed, combined with known information about the water density, and converted to a height measurement. The height measurement is typically recorded on a data logger.

Here's a schematic:
Error:
There are a couple sources of error associated with pressure transducers:
1.) Air pressure above the water must be accounted for
2.) Since the pressure transducer is measuring pressure and converting it to water depth, the density of the water is a critical parameter. For instance, salt water has a different density than fresh water. Cold water has a different density than warm water.

Other Concerns:
Pressure transducers may be damaged if exposed to extreme pressures.

Characteristics:
Range: 0-40 feet
Accuracy: 0.1% of the full range

First Look at the Water Level Bench

Today I had the chance to work in the lab a little bit. I spent a while just sweeping up a lot of grit and dirt.

Since the bench has been completed I put some water in it and took a series of photos. Hopefully those will be useful for Ken to look at as he works on his software.

Ken also has been in contact with Ruby Mehrubeolgu, who has some interesting water/machine vision work going on down in Corpus Christi. A lot of grant solicitations emphasize collaboration between universities, so it is possible we could work together on something if interests, timing, etc, align.