All posts by avishek.sen.gupta

Tests increase our Knowledge of a System: A Probabilistic Proof

This was an old proof that was up on my old blog, but since I’m no longer posting to that, I’m reposting it here for posterity. Also, rewriting the equations in LaTeX, now that I have installed a plugin for that.

I present a simple mathematical device to prove that tests improve our understanding of code. It does not really matter if this is code written by the test author himself or is legacy. To do this, some simplification of the situation is necessary.
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Playing around with Self Organising Maps

SOM Evolution
(Click the image to see the evolution of the SOM)

The image above was generated off 200 samples of a large data set. Sample vectors were 56-dimensional bit strings. The similarity measure used was the Hamming Distance. Brighter green represents values at a higher Hamming Distance with respect to zero.
The (very dirty) code is up at Github here.
Unrelated: I’ve been watching Leonard Susskind’s lectures on Statistical Mechanics; they’re a tour de force.

Facial Expressions as Volumetric Deformation and Displacements

I was working through The Artist’s Complete Guide to Facial Expression by Gary Faigin. Pretty thorough book, and the facial landmarks for different expressions are well detailed. Except that I was still having problems inventing expressions. I mean, yeah, expressions can vary a lot, but I think what I was looking for was a system using which one could ‘generate’ expressions on demand, without having to copy from something.
The problem I see with copying is that I’d end up copying the facial characteristics of the subject I’m copying as well, which hardly bodes well for the (imaginary) face I’ve cooked up. And yes, it wouldn’t affect my drawing that much, but I was still unsatisfied with that idea.
This afternoon, an idea struck me: what if I used the same system I use to generate poses to generate expressions? If you really think about it, the face is just a bunch of muscles with fat over them with the layering of skin. If I could figure out the forms at the appropriate resolution, these forms could be blobs which could be displaced/deformed at will to generate expressions. Boundaries of jostling blobs basically become potential creases and wrinkles. Blobs which get squeezed on all sides by other forms bulge out.
The idea seems to be working.
Continue reading Facial Expressions as Volumetric Deformation and Displacements

Inventing poses

It’s not easy imagining them. But it can get better with practice. And that’s what I’ve been doing. An excellent accompanying read is Force : Dynamic Life Drawing for Animators. It’s one of those books that’s perfect for kicking you out of a rut, inspiring you to loosen your strokes. It’s worth several rereads; I’ve only skimmed through some parts of it, and they are immediately useful.
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Ughhh, almost forgot about this place; well, better late than never.

Yeah, I’m on a holiday now. And suddenly, it seems that there’s a ton of things to do.

Focusing a lot on improving my drawing/shading technique. I’ve gone back to pencils, sworn off digital painting till I get some experience working with colors in real life. Not that prevents me from messing around with Painter. Been doing a few drawing sessions with people at work, after work; so far, the results seem encouraging, i.e., no rotten tomatoes yet.

I used to hate having to get to work to scan my drawings, now I completely detest it. Firstly, I’m too lazy to take a stroll down there while I’m on vacation. Secondly…well, I think the first reason is good enough. So I went over to the local Croma store and snagged a HP Deskjet J610a. Primarily using it for scanning, but taking a printout should come in handy too. Installation was a snap, though the scan of the white areas of the paper have a slight sepia tone. Nothing a little color correction can’t handle.

As a side effect of this increased drawing output, I went ahead and cleaned up the site after a (very) long time. Installed Plogger today to give the new stuff I’ve been drawing a better presentation, threw away the old home page, et cetera. Well, at least this evening wasn’t a total waste…

Also found the time to run all my books through the MyBookDroid app: not bad so far. The books I’m currently reading are:

  • Figure Drawing: Design and Invention – Michael Hampton
  • Castles: Their Construction and History – Sidney Toy

Continuing work on Exo next week; I want to try out an easier way of weaving IL without tacking in IL for every aspect that is specified.

Been trying out this very funny game called Magicka. I highly recommend giving it a try, it’s hilarious, drops fantasy cliches left, right and center; and the narrator keeps insisting that the player’s mentor ‘Vlad’ is by no means a vampire.

Checked out the new Incarna character creation system in EVE Online; they did a nice job of it; should be fun when they introduce in-station ambulation.