GaugeCam system used in Bangladesh!
GaugeCam background set up in small irrigation channels in Bangladesh
The GaugeCam system was recently used in Bangladesh during experiments related to Arsenic dissipation in irrigation channels. These experiments were conducted by Dr. Polizzotto, Mr. Lineberger and Dr. Birgand in December 2012. These experiments were done to generate preliminary data to evaluate the ability of ecologically engineered systems to strip Arsenic from water in small irrigation channels.
One of the factors at play is the height of the water column above the substrate in the channels. We thought it would be nice to use cameras and the GaugeCam system to measure the levels in the channels. So that is what we did! The system set up can be seen in the picture to the right.
Our original GaugeCam camera is dedicated to transferring images on a real time basis to our server. Our camera can also save images on an SD card. The ratio quality/size of the images is outstanding and that is the reason for our preference.
Line detection of water level in irrigation channel in Bangladesh
For short term experiments, we only needed the SD card writing capabilities. In fact we believe this might be the case for many people!
We have explored the capabilities of using hobby type of equipment (Arduino based systems) to build a camera able to take time lapse pictures.
Thanks to Dr. Kyle Aveni-Deforge, we have built such a camera, which we now call ‘mini-GaugeCam’ for a cost of about $150 for parts.
Obviously, the quality is not nearly as good as our original camera, but one can still obtain some very decent images. In fact, we had no problem finding water lines (see picture above).
As it turns out, our experiments lasted less than 30 min each and at constant flow. So in the end we decided to read the water heights directly on the gauge staff.
Thanks to our ‘mini-GaugeCam’, we were able to very easily set up the camera, the background and the gauge staff and obtain 1-min interval pictures and verifiable measurements! This, we think, should interest a lot of people! More on the mini-Gaugecam later.
GaugeCam represented at the NC State University innovation fair
The College of Agricultural and Life Sciences (CALS) at NC State was hosting a conference: “Stewards of the future: Research for Human Health and Global Sustainability“. Along with the conference, CALS hosted its Innovation Fair. GaugeCam had its booth entitled: ‘Hydrology for all: measuring water level using webcams’.
Our booth had posters, videos, a slide show of how the system works and of results, live data streaming from the field and a display of the GaugeCam hardware.
We must admit that few people did stop by but we did obtain some true interest and that was good. Thanks to the conference, we did make quite a bit of progress on the live web site.
Our camera did not weather Irene but damage may be small
Irene’s eye went right over our site! Unfortunately, some rain water managed to get into the casing of our prototype camera. It has been sent back to Colorado Video for damage assessment. We are confident that things should be OK though as there was water just at the bottom of the camera. Damage is probably moisture related so it is not as dramatic as if the camera had been ‘swimming’…! In the mean time, the second version of our prototype is being shipped and will be installed on site as soon as possible.
The GaugeCam installation in the field
Marsh pictures have been streaming since July 17, 2011 with generally great success and we have learned a lot about what it takes to send images from a totally remote place, located half an hour away from the first paved road. Images are streaming from the North River coastal marsh restoration project located near Beaufort, NC.
So, what does it take to have a GaugeCam system to measure water level in a stream?
First, it takes the camera that will do the trick of capturing pictures on a desired interval and of automatically sending the pictures to a server. Second, it takes power: good batteries and good large solar panels. Third, it takes a good white background with embedded fiducials. Fourth, it takes a stable camera mount.
First, the camera. The GaugeCam project and company would probably have remained at the stage of a great potential project, had we not discovered the Colorado Video company and its very good products. We are using a prototype of the Lookout V camera.
To be short, the camera has an embedded cell phone which sends pictures via a 3G card. So in essence, one needs 3G network coverage for this camera to work properly. We have experienced blackouts where the pictures do not go through. The first reason for that was that our (still small but that is about to change) server was full…
There also seems to be a somewhat erratic pattern of missing pictures between 22:00 and 02:00 at night. It seems to come and go and we have not been able to find a true reason on our side. We are thinking that it might result from the 3G network operator, although we have no actual data to prove this.
Second, the power system. We have a 55W solar panel to recharge two regular car batteries installed in parallel. Voltage has never gone below 12.4V. The marsh has no shade and is a great place for solar panels!
Third, the background. This is a critical part of the set up as it has to withstand the rigors of the field (sun, water, biological activities, etc.), remain flat and vertical. Actually, verticality is not necessary but it certainly helps to keep fouling to a minimum. The background that you see in the pictures is a film of plastic that has been laminated over a ½ inch think piece of Plexiglas by professionals. The background is attached to two posts that have braces to maintain verticality. It is essential that the background does not move! We will check regularly to verify that it does not!
Once the background is installed, it is important to measure the real world coordinates of the fiducials. This is really the critical part that all hydrologists and equipment installers have to do. Despite all efforts, it is our opinion that it is very difficult to make this measurement better than ±2 mm. This is particularly difficult in the marsh where the water level was changing all the time because of the tides. When the level hit the center of the lowest fiducial centers, water level was simultaneously measured above our reference value using a graduated ruler. All future measurements are then dependent upon that first call… Actually, other manual measurements will be done and if a bias towards over estimation or underestimation is detected, it will be taken as an offset to calibrate our instrument.
Fourth, it takes a good camera mount. This might end up being one of the most challenging task, especially in remote areas. Several options are possible: concrete, wooden or metal mounts… We abandoned concrete as it would not be desirable there for many reasons. We thought that metal would be very challenging because of varying moisture, salinity and temperatures. So we went for wood (see pictures). Braces were installed with the post to reduce vibrations from the wind. However, we have already noticed that images are looking more and more to the right as the whole mounting device is warping.
The camera itself is protected in an open wooden box which size has been reduced to a minimum to minimize wind effect.
We are learning a lot from this experience and are adjusting our software and hardware accordingly! We will keep you posted!
