Read posts about math

September 25

CHDK (eccentric squares (Kuya)) by noel

the canon hacker's development kit allows you to upload user developed software upgrades to your canon camera. i tried it on my trusty old SD700IS and it worked great. what initially drew me to CHDK was the auto exposure bracketing, since i was looking into some of that computational photography stuff. here's a list of features from their FAQ:

  • Shutter-priority (Tv) exposure - via shutter value override feature
  • Aperture-priority (Av) exposure - via aperture value override feature
  • Shooting in RAW, with RAW Average, RAW Sum, and RAW Develop features
  • Live histogram (RGB, blended, luminance and for each RGB channel)
  • Zebra mode (a live view of over and under-exposed areas of your picture)
  • Depth-of-field (DOF)-calculator, Hyperfocal-calculator with instant Hyperfocal and Infinity focus-set, and more
  • Battery indicator
  • RAW and Video space-remaining gauges with custom low-limit alerts
  • USB cable remote shutter release
  • Motion-detection trigger - automatically fires camera on motion detection. (Fast enough to capture lightning strikes.)
  • Customizable high-speed continuous (burst) Shutter-based (Tv), aperture-based (Av) and ISO-based exposure bracketing (unlimited shots)
  • Focus bracketing (unlimited shots)
  • 99 constant bit-rate and 10 constant-quality video compression levels
  • Elimination of 1 Gig video-size limit
  • Zoom during video function (for cameras without this feature)
  • Shutter, Aperture, and ISO Overrides
  • Ultra-long shutter speeds - up to 64 seconds
  • Ultra-fast shutter speeds - up to 1/10,000" and higher
  • High-speed Flash Sync at all speeds up to 1/64,000 second (even faster in some cameras)
  • Custom user-editable visible Grids for framing, cropping, and alignment
  • File browser
  • Text reader
  • Calendar
  • Some fun tools and games :)
  • Fully customizable CHDK display, info placement, user-colors, fonts in menus, etc.
  • Custom CHDK User-Menu (for instant recall of up to 10 favorite functions)
  • Scripts execution - including exposure bracketing, focus bracketing, intervalometer and more)
  • And other features too numerous to mention here. See the CHDK Firmware and Allbest Firmware usage pages for a more complete overview.
and a list of supported cameras:

if you have one of the listed cameras and are looking for any of the above features (or are really just looking for a painless way of getting your money's worth out of your camera), i'd say check out CHDK.

Posted in: cs , engineering , math
August 15

computational photography (eccentric squares (Kuya)) by noel

i'd gotten interested in computational photography at my last job, where i applied some HDR algorithms to satellite data. at SIGGRAPH, they offered several talks/papers on the topic as well as a great class (esp the sections given by jack tumblin) which reviewed the recent academic literature (there's been a lot) from the past 2 years.

at this point, the relevant question would be: what is computational photography? according to their website:
Computational photography combines plentiful computing, digital sensors, modern optics, actuators, and smart lights to escape the limitations of traditional film cameras and enables novel imaging applications. Unbounded dynamic range, variable focus, resolution, and depth of field, hints about shape, reflectance, and lighting, and new interactive forms of photos that are partly snapshots and partly videos are just some of the new applications found in Computational Photography.

an excess of text in a post about imagery is pretty lame, so in this post, i'll just describe (at a super high level) and link to some cool applications in this area.


the area that i had initially gotten interested in and which is becoming much more mainstream now is HDR imagery. high dynamic range images are ones which have scenes with super bright areas and super dark areas. to capture HDR images, ordinary cameras will capture several exposures of the exact same scene. post processing will combine the exposures into a single image which effectively conveys those high dynamic ranges on our low dynamic range monitors. tweaking the parameters to these algorithms can give photographers artistic license, yielding sometimes surreal looking photos:


programs like photoshop currently support HDR file formats and tone mapping and certain cameras offer features like auto bracketing, which can help in acquiring the exposures used as inputs into HDR tone mapping.



another easily accessible area is in panorama/auto stitching. these have been out for a while now, i got a program to do this with my canon SD700 2 years ago and photoshop CS3 has this in there too. this is a complex problem however, as if you've tried stitching together >100 gigapixels worth of images together, you'll find out what your computer isn't so happy. a recent SIGGRAPH talk demonstrated an algorithm which took an hour crunch on a notebook on a problem which took my work computer several days (before crashing and burning).



a couple areas were targeted towards removing blur from photos. a couple years ago, mitubishi announced it would develop a camera which would facilitate motion deblurring. the image linked above and this paper (both show some pretty amazing results) are software techniques to remove blur. this paper (image below) even gives an algorithm for removing haze:


with sites like flickr, the widespread availablity of geolocated images is now a reality. one pretty freaky project builds up a statistical analysis of the outdoor lighting conditions in these large data sets so that, given a time stamp, the system can identify the location to within 50 miles!



if you've ever had to crop or resize an image, watch the video above. they have a method to interactively size images and movies without distorting proportions. ...just watch it.



a super cool demo related to the problems i work on now is microsoft's photo tourism/photosynth. it effectively recreates 3d spaces from 2d photos, allowing the user to take virtual tours.



above is another cool demo out of microsoft research called unwrap mosaics. the intermediate stage (the unwrapped mosaic) is frightfully reminiscent of a picasso painting, but the end product and apparent ease with which its produced is almost comically easy.
Posted in: cs , engineering , math , pictures , video
April 28

i like to move it move it, ya like to MOVE IT! (eccentric squares (Kuya)) by noel

i switched careers recently, from the aerospace industry to the entertainment industry. i'm working at a motion capture company, and to get us up to speed on the system, we spent the day as talent (aka actors). here are some pics from that day (keep in mind that we're actually getting paid for this hahaha).

Posted in: cs , engineering , math , pictures
April 18

Math geekery ++ (Kilala.nl (Cailin Coilleach)) by Cailin Coilleach

I just love this line, paraphrased from here. At least, somewhere over there ^_^

Complex variables and computations are fun and games, until someone loses an i.

Glee! XKCD makes my Friday afternoon a happy one again :D

Posted in: ++ , complex , geek , math
March 7

you are here (eccentric squares (Kuya)) by noel




i've told people before that i spend a large amount of time at work, just staring at the clouds, here's an example of what i really mean. in testing some of my code, i randomly pulled this data for unit testing purposes and it was so pretty, i decided to make it my desktop wallpaper. i put this composite together with that code along with some manual editing in photoshop.

originally i wanted to take the original and make posters of it, but it got watered down significantly in the process for making it fit for public consumption. i've literally spent hours just zooming into and admiring the expected and unexpected features in the unaltered images. it's pretty cool to make animations out of these too. anyway, i think this version still looks pretty amazing (especially if you haven't seen the earth in infrared before) and it's probably also the most expensive desktop wallpaper evar lol.
Posted in: cs , engineering , math , pictures

they are there (eccentric squares (Kuya)) by noel

another public release image below, sanitized for the unwashed masses. you'll notice that this one is just black and white. well, that's because i had massively photochopped the other one lol. in that picture, i had just taken the intensity values per pixel and multiplied by the blue from the NASA visible light Blue Marble photos. this one is slightly truer to it's native form, where the brightness of each pixel is some funny function (my aesthetic preference) of irradiance.


Posted in: cs , engineering , math
February 7

I taught my first class today (Kilala.nl (Cailin Coilleach)) by Cailin Coilleach

The Cals College in IJsselstein
Oh. My. God. I was so nervous this morning, it's unbelievable!

This morning I headed over to the Cals College in IJsselstein, to teach a class for the first time ever-ever. Before that, I had an appointment with the school's student care coordinator, to discuss another school assignment. Fifteen minutes before my class, I was in pretty bad shape though. Crampy stomach, cold and clammy: also known as "nervous".

The same went for the first two minutes of my teaching: I had a shaky voice and kept losing track of my story. After that though, things were fine :)

The students in my classroom were nothing short of awesome. Just like my classmate had predicted, they were very kind ^_^ They were very attentive and they were fast on the uptake. They all managed to finish the whole stencil of assignments, with only a few making minor mistakes. I couldn't have wished for a better class.

<dutch>
Klas 1DLW, heel erg bedankt voor vandaag! Ik ben heel erg blij met hoe het is gegaan en had geen betere klas kunnen vragen voor mijn eerste les. Heel veel succes nog met school en misschien tot ziens :)
</dutch>

One point of important feedback that Gineke gave me: at this level of education, the questions I ask to verify the students' learning process are too open. Instead of asking if everyone gets it, I should ask more closed questions to see if people give the correct answers. Were this VWO instead of VMO (uni-prep as opposed to vocational school), -then- I could've asked open questions.

Of course, there was more feedback, but I'll put that in my report for school. This will be published in the School section in a few days.

Here's a snippet from the videotape I made for my portfolio.

NegGetal.mov

Posted in: class , first time , math , teaching , virgin
January 31

It's finally going to happen! (Kilala.nl (Cailin Coilleach)) by Cailin Coilleach

Well, it's finally going to happen! I've been putting this off for a long while, but Marli kicked me hard enough to get over it.

I'm going to teach a class.

The very thought still makes my stomach do somersaults, it's silly really. This is exactly what I'm studying for, so I ought to be longing for this moment! Of course, I realize that stage freight is something completely natural, but to be putting it off for months on end is just stupid. But now it's going to happen! In part because Marli got me out of my rut and in part because I'll fail my VAKDID2 class if I don't D:

My classmate Gineke is giving me a huge break, but letting me teach this class to one of her first year's groups. She tells me their absolute sweethearts, so I really have nothing to worry about.

In a week's time (OMG!DEADLINE!) I'll be introducing a group of first year's students to the concept of negative numbers. On the one hand this deadline's great, since it's putting some real pressure on me. On the other it's a bit scary, because I really have to push myself hard to make it.

I'm going to teach a class.

My very first time, in front of a room filled with youngsters that -aren't- there to listen to me talk about anime or Japan. My very first time, trying to educate the young. My very first time, making my career switch more real than it ever was! This is why I've been working my ass off the past few months. I need to remember to enjoy the experience and not just try to be perfect.

I'm going to teach a class.

Oh my!..

Posted in: college , finally , high school , math , teaching
August 31

Teaching is popular. Maths even more so. (Kilala.nl (Cailin Coilleach)) by Cailin Coilleach

Last night was the school year's official opening at Hogeschool Utrecht. Around 17:00 all aspiring tweedegraads teachers gathered in the cafeteria for a speech from the rector. It was interesting to see that the group was both large and varied. I reckon there were about a hundred people there, maybe one-twenty. Aged between twenty and somewhere in their fifties I saw a lot of caucasians, mixed in with a few turks and moroccans.

One startling realization was the fact that almost 50% of the group were there for the same degree I was after: tweedegraads maths teacher. I guess either it's a popular passtime, or people have caught on to the fact that maths teachers are sought after. All in all there's sixty people starting the maths course this year. Wow!

After the whole introduction and a tour of the school building (which we'll be leaving come January, to move to a new one) there were drinks. I finally got the chance to meet some of my fellow students. It's slightly daunting to know that a whole bunch of them are already in education, but I'm not going to let that get in my way :)

So far they seem like a nice bunch of people! There's the strong-and-silent guys, the rowdy drinking-after-playing-footbal guys, the silent-and-mousy women and so on. There was also this one woman (I think she's in her forties though I'm horrible at guessing ages) who's great! She's absolutely bubbling with enthusiasm for the course! Kind of like how I felt after my intake with the coordinator :)

Yes. This is going to be an interesting year!

Posted in: career change , college , docent , math , teaching
August 14

Maths revision (Kilala.nl (Cailin Coilleach)) by Cailin Coilleach

Seven math books
Since school starts in about three weeks I thought it was about damn time to start getting prepared! It's one thing to make all arrangements with the school, taking care of paperwork and talking to people. But it's another thing entirely to actually be prepared for the course material!

I graduated from college a little over seven years ago. For about half of my college years I was very busy with maths, learning all kinds of new tricks. All the other time was spent programming, doing web design and learning about Unix. Since my career progressed with the latter half of what I just described, it's only natural for my maths to be a little rusty.

Well, rusty would be an understatement. Consider if you will one of the original, iron nails that Noah had used in his arc. Having been exposed to tremendous amounts of sea water and ages upon ages of time it's sure to be a bit rusty. Now, let's assume that ever since that flood the nail had been exposed to corrosives, acid rain and various other nasties. Not much would be left of it, right? A nasty, little chunk of iron would be all that's left.

Well, that's where my current grasp of maths is.

Thankfully I am confident that I can at least completely revive my high school math skills, considering this blog post. Back in 2005 I prepped Marlijne for an exam that consisted of all my HS maths in only a few hours.

Also thankfully, unlike what I wrote in that blog post, I did -not- throw away my math books! /o/

The picture above shows all of the books that I want to go through before school starts. The bottom row (plus the b/w book at the top left) are all high school books from my final two years. They cover everything from functions and equations, through trigonometry, to differentials and logarithms.

The top row is the stuff I went through in college. It's also the stuff that currently gives me a dread feeling in my stomach because it is way beyond me. They start out by repeating a little bit of HS stuff (differentials, functions), but then quickly move on to limits, logarithms, partial differentials, integrals, multiple variable equations and vectors. Zounds! I won't even mention the two other books that cover Laplace transforms and Fourier strains. Although I doubt whether I'll need to know any of that stuff.

Unfortunately I -have- thrown out all of my syllabi, meaning that I'm out of materials on chance calculation and on matrices. Luckily my friend The Saint is willing to lend me his copies. Apparently his storage space is larger than mine and he's hung onto most of the stuff from our college years ^_^

Well! Here I go! Study study study!

Posted in: math , oh dear , revision