Today I've three textbooks on Offshore Geotechnical Engineering and stack of two dozen papers on offshore wind turbine foundations sitting on my desk, waiting to be read. I'm starting to take a crack at them, working through soil mechanics problems from undergraduate exams along the way. This evening I'm really looking forward to a talk from Dr. Linda Hulin in the Archaeology School about her and Dr. Damian Robinson's work in Maritime Archaeology. I'm especially curious to hear about the technology they use in their field expeditions. After the talk is the Oxford Marshall scholars are getting together. Looking forward to catching up with them, and hoping to get some ideas that will help pinpoint my thesis.
Today I'm reviewing Section 4: 1D Compression and Consolidation in Soil. This involves marking a text and then solving related example problems to check my understanding. This is sometimes draining work, but this morning (thanks to the delicious pizza from yesterday?) I was so focused I lost track of time and almost missed lunchtime ballet class. One of my goals this term is to increase my attention span (useful when you have 30+ scientific papers to read through on a monthly basis and weekly "dry" academic talks). Ballet helps with that! Plus it's something I look forward to. Coming out of Mission 31 I was in great shape, but now thanks to English pub food and being a graduate student who doesn't really cook I'm starting to lose it.
I'm eager to settle on a thesis topic, but my supervisor has stressed that in the next few weeks it's important to keep an open mind, get an overview of the field, and have a solid understanding of basic concepts. So I'm learning and being patient. Possible topics include offshore wind energy and/or developing control systems for test equipment in the civil engineering lab. I want my thesis to have broad implications in technology-based exploration, and affect how we use technology to better manage the ocean. I may collaborate with the computer science department. Much is still uncertain. As an aside, I finally discovered Ed Sheeran's new album (the one that came out half a year ago); it makes a lovely working soundtrack. Finally, as usual at Oxford, there's plenty to look forward to this evening. Eric Schmidt and Jonathan Rosenberg are speaking at the Oxford Union. Schmidt is talking about the book he co-authored, "How Google Works," but I wish he was talking about his family's ocean foundation. I had the pleasure of exploring the Schmidt Ocean Institute's research vessel the Falkor while it was docked in Woods Hole two years ago. The Schmidt Ocean Institute is an example of how ocean exploration is funded from the private sector -- see New York Times article about Wendy Schmidt. Even though I'm studying for a degree in the technical side of things, it's important to keep a perspective on who will care about the research and how funding is coming into the field. Never a dull moment, there's more salsa dancing later in the evening with other Marshall Scholars so it'll be plenty fun. My plan is to go to sleep all danced-out and be laser-focused again in the morning for Section 5: Strength of Soils. My favorite part of the day was Skyping with Ignacio Esquivel's 9th and 10th grade biology class at Arandú High School in Costa Rica. The students asked excellent questions, such as "How has your perspective changed about everything that is happening in the ocean with the technology you are creating?" (from Juan Manuel Badilla). I was impressed that they had already watched nearly all the Mission 31 videos and read my main blog, so they knew all the basics. Kudos to their excellent teacher Ignacio, whom I met through his brother Manuel at MIT several months ago. Ignacio said his goal was to "get them to open their minds and start aiming high with their dreams. I want them to know that, whatever they become (lawyers, doctors, marine biologists or mechanical engineers (hopefully), etc.), they are capable of changing this world and that there is no age established for this, that they may start NOW." I certainly support that! I realize this isn't a super suitable topic for the "technical blog" so I'll also post about this on my main blog when I get a chance. Earlier in the day I was at my office, reading Section 3: Steady Seepage Through Soils from the text of a soil mechanics course. It's easy to go zombie when reading on your computer for long hours. Fortunately my reading session was broken up by compulsory induction sessions for new graduate students, the first on how to use library resources and the second on health and safety. Most of the second talk was geared towards graduates using chemicals in their laboratory work (some chemicals can burn through your bone and blind you... yikes, thankfully I'm not a chemical engineer!). After the sessions I finished two exam problems that tested my (newly gained) understanding of flow nets, which are used to solve seepage problems in soil. Feeling good about finishing these problems, I headed to the Maths building (in England they say "maths" not "math") for a welcoming reception for new graduate students in Mathematical, Physical, and Social Sciences (i.e., several hundred students). It was lovely but somewhat overwhelming meeting so many people. I ran out early to attend a salsa dancing class with another member of my college. After salsa we got a totally delicious pizza from food truck by Pembroke College that (amazingly...) had a wood-burning oven inside the truck. Today in a nutshellIt's super rainy and grey outside. Perfect weather for the first day of my PhD studies, which will mostly involve sitting at my desk reading papers and solving problem sets, at least for the first few weeks. This morning my supervisor, Dr. Byron Byrne, gave me an overview of what other graduate students in the group are doing. Most in his group work on monopile foundations for offshore wind turbines. My goal this week is to get a handle on current research in the field of offshore geotechnical engineering. I'll start by making sure I can finish a problem set from a senior undergraduate course in soil mechanics. This is important not only so that I have solid foundation in the field (pun), but also so that I'll pass the interview stage of my "transfer of status" exam next fall, when they'll test my understanding of basic soil mechanics concepts. Fortunately the work is very similar to what we covered in Mechanics & Materials courses at MIT.
I learned about Abaqus Finite Element Analysis (FEA) software today, and have a feeling I'll be using it later on in my research. I'm also accumulating a knowledge bank of new acronyms, e.g., EDF is the French electricity giant, PISA is an organization for improving offshore wind turbine design in deeper waters, et al. One of my early projects may be modifying a piece of test equipment, changing the control system from displacement based to load based (and controls from Visual Basic to LabView). I'd also like to connect with the Global Ocean Commission, International Maritime Organization, and the National Oceanography Centre in Southampton. Meanwhile, on slate for the rest of the day is reading about a dozen papers, titled " Helical Screw Piles as Foundations for Offshore Wind Turbines," "Investigating six-degree-of-freedom loading of shallow foundations on sand," and more. The underlying mechanics concepts are not new, but sand-specific concepts are (pore pressure, flow nets, etc.) are fairly new to me so I must review. After work I get to look forward to poetry reading at the Rhodes's house, followed by drinks with the Archeological Society and then a pub night with the other Marshall Scholars. Oxford quickly turns you into a social butterfly! Oxford University's default mail client is Outlook, but I wanted to work through Gmail. On the web I was surprised to find only outdated instructions for linking with Gmail, and they didn't work. The trick is that you have to wait to link your accounts until about 30 minutes after you activate your Oxford account. In other words, don't be an eager beaver. Then:
The verification email from Gmail will most certainly go to your Spam folder, so check that afterwards. Once you click the link in that email you're all set!
AFTER CHANGING YOUR UNIVERSITY PASSWORD (AS YOU'RE REQUIRED TO DO EVERY YEAR), YOU'LL NEED TO RE-DO THIS, OR ELSE YOUR EMAILS WON'T SEND :( using matlabThe latest version of MATLAB (2014) has a built-in Camera Calibrator. You can learn to use it here. You feed it about a dozen images of a checkerboard, and it will automatically determine the camera’s distortion. Sounds great, but it couldn’t detect the corners in most of my images from an underwater camera. It didn't work. UPDATE (21 APRIL 2015): The MATLAB Computer Vision System Toolbox team has been very proactive in addressing this issue. It's worth trying their system again. This worked: The Camera Calibration Toolbox for MATLAB, downloaded here. It requires you to manually click corners of the checkerboard in your images; it sounds tedious but it’s not really. Your results will look something like: Focal Length: fc = [ 1755.04324 1754.95349 ] ± [ 22.44731 20.56242 ] Principal point: cc = [ 650.63208 545.93890 ] ± [ 18.33014 16.47342 ] Skew: alpha_c = [ 0.00000 ] ± [ 0.00000 ] => angle of pixel axes = 90.00000 ± 0.00000 degrees Distortion: kc = [ 0.16858 0.57600 0.01030 -0.01824 0.00000 ] ± [ 0.03928 0.30327 0.00512 0.00548 0.00000 ] Pixel error: err = [ 0.66638 0.47196 ] The toolbox lets you undistort one image at a time. I used openCV to undistort a batch of 20,000 images by running the script below and plugging in the above parameters. That said, there’s probably a way to do this in MATLAB with a for loop and the undistortImage function. import numpy as np import cv2 import glob # copy parameters to arrays K = np.array([[1755.04324, 0., 650.63], [0, 1754.95349, 545.9389],[0, 0, 1]]) d = np.array([.16858, 0.57600, 0, 0, 0]) # just use first two terms images = glob.glob('/Users/Grace/pythontest/imgs/nui004_proc_origionals/*.tif') for fname in images: # read image img = cv2.imread(fname) h, w = img.shape[:2] # undistort newcamera, roi = cv2.getOptimalNewCameraMatrix(K, d, (w,h), 0) newimg = cv2.undistort(img, K, d, None, newcamera) # save image newfname = fname+'.undis.tif' cv2.imwrite(newfname, newimg) Using opencvYou can also, theoretically, do the whole calibration in openCV. It didn’t work for me though because openCV wasn’t able to detect the checkerboard corners in most of my images. In any event, the instructions are here on Solem’s vision blog, where most of the code above is from. I found his method easier than the one on the openCV python tutorial. You'll find the calibrate.py function you need in opencv/samples/python2. One note is that Solem says to use
$ python calibrate.py “calibration_samples/GOPR00*.JPG" But this only worked for me without the quotes, and with a tilde; e.g., $ python calibrate.py ~/pythontest/left0*.jpg |