Archive for the ‘machines’ Category

i like cold beverages

July 6th 2008

arrow ice thumb
arrow ice close thumb

Some time ago I bought these silicone ice cube trays from Ikea. Ice cube tray a very serious misnomer, because the ice that comes out of these things is anything but cubes. But the ice is in fun shapes (I got the arrows and crosses), so it’s a little sad to see that the Ikea PLASTIS line of ice-making molds is no longer in stock (nb: you can still purchase a very similar item from Amazon).

ice cross thumb
ice cross close thumb

So I’ve been making humorously-shaped ice for quite a while now, and the other day I was torn between using ice arrows or ice crosses to cool my tasty beverage. At this very moment I questioned which shape would cool my drink more quickly. That is, does the ice arrow or the ice cross have more surface area?

ice measurements thumb

It’s a pretty simple problem to solve, and anyone who graduated from Jr. High geometry should be able to figure it out in less than 5 minutes. I present here the precise measurements that are necessary to get the answer. My solution is here (spoiler alert!). I hope you agree.

icosahedron thumb

This train of thought led me to conclude that an ice shape that would cool your drink most quickly would be one with the maximal possible surface area in a given volume. If only someone could engineer a tray that makes ice in the shape of a high-order icosahedron. That would get your drink cold in no time flat. Or better yet, something approaching a fractional dimension, where you’d probably need advanced degrees in math to even predict the cooling effects of such a hypothetical ice shape on a beverage.

That is all.

Posted by dylan under machines | 5 Comments »

conquering my visual cortex

December 21st 2007

Today is a landmark day where I fought a pitched battle against my very own visual cortex, and I am proud to say that I emerged triumphant. No doubt you’ve seen those pictures of a bunch of colored dots, where if you stare at them long enough a 3D picture is supposed to “pop out.”

shark stereogram thumbnail

I remember these used to be popular circa 1995 when everyone had huge Magic Eye posters plastering the walls[1]. In the 10 years that I’ve been staring at these speckled dot things (autostereogram, to be precise) I never really got it. The advice people tell you when trying to perceive these images is vague and unhelpful: “you just have to stare at it long enough!” Sometimes it worked, usually not[2]. Until today.

Espousing the wikipedia is passé, I know, but I feel it’s necessary because this page has allowed me to overcome a decade-long frustration and master my own personal visual perception system. The reason why it’s so hard to “see” an autostereogram is because you’re asking your brain to do something totally unnatural. Millennia of evolution have hard wired the actions of focusing and convergence into your eyeballs. Stereograms are basically just a dirty trick on the brain, and for the illusion to work you need to defeat your subconscious reflexes.

simple stereogram thumb

It’s helpful to understand how exactly the illusion works, and to practice on simple wallpaper images like this one. Then you can move on to level 2, random dots. It really is just a matter of practice and training. Once you’ve mastered the control of your visual cortex, it’s a cinch.

stereogram composite

I’m impressed at how, once locked into the illusion, you can flip between images without having to recalibrate yourself. Take a bunch of images (here’s a zip file of 50) and make them into a screensaver or slideshow. You should be able to switch pictures and stay in 3D the whole time.

Easier, download these quicktime movies I made that cycle through the whole bunch automatically:
1 second per frame or 3 seconds per frame

For best results, open in Quicktime and go to “View” -> “Present movie…” -> “Actual Size.” Stereogram animations are also cool. For the ultimate challenge try this on for size… stereogram tetris! I played for 10 minutes it left me unable to look at still objects, or walk straight.

[1] 1995 was also The Year of the Fractal. Computer-generated images used to be cool.
[2] Turns out I was doing it all wrong. I was crossing my eyes, which made the images inverted. Most stereograms are rendered to be viewed “wall eyed.”

Posted by dylan under humans & machines | 6 Comments »

infrared digital camera, pt. 3

November 5th 2007

point reyes hills in infrared thumb

The short story: I modified a crappy digital camera to make it capture infrared images. Step-by-step instructions available at this instructable.

The long story: A fortuitous sequence of events has led to the successful creation of a real, actual infrared digital camera, done right. The first step was to get my hands on a reasonable digital camera (ie: one that was actually compatible with my computer). For this, I marched straight into the nearest Ritz Camera store, walked directly to the counter, and stated “I would like to purchase your absolute cheapest digital camera, because I have every intention of possibly breaking it.” On that lucky day, there was a very nice woman working the register who simply reached down below the counter into some sort of lost-and-found and retrieved an orphaned VuPoint 3.1MP digicam. “You can have this one, if you want,” she said.

Not one to look a gift digital camera in the mouth, I graciously accepted the offering, said my thanks, and immediately left. Granted, this camera is just about the bottom of the barrel (fixed focus, plastic lens, dim LCD, generally cheap components), but it *does* have a removable SD card that I can simply stick in my USB card reader to make it interface nicely with iPhoto.

infrared digital camera thumb

Having procured 1/2 of the necessary components, the next step was to order a sheet of Congo Blue (Lee #181, Rosco #382) lighting filter gel from B&H. Once everything arrived in the mail, it was time to get down to business. In short, the idea here is to crack open the digital camera, remove the IR-blocking filter, replace it with lighting filters that block everything *but* infrared, and reassemble the camera, hoping nothing got broken along the way. Again, this is all describe in detail on this instructable.

The surgery was a complete success, and I now have in my possession a 100% certified infrared digital camera. For something that cost slightly more than $0, I am completely in love with this camera. Here is a smattering of pictures that I took at Point Reyes National Seashore and more recently at the Russian Ridge Open Space Preserve. Yes!

Posted by dylan under machines | 1 Comment »

infrared digital camera part 2.

October 7th 2007

Prior to dismantling and potentially destroying a perfectly good digital camera for the sake of an infrared modification, I have embarked on an simpler way to achieve the same effect. What it boils down to is this: the CCD on your average ordinary digicam absorbs infrared light quite effectively, so much that camera manufacturers try their hardest to block IR from ever reaching the detector. They install an IR-blocking filter behind the lens that mops up most but importantly not all infrared from getting through. So it’s actually possible to take an infrared picture using an unmodified digital camera, if you trick it. By placing a filter in front of the lens that blocks out every thing *but* infrared, you can in fact produce an IR image.

I went to a photo store and picked up a sheet of Roscolux #27 “Medium Red” filter gel. If you look at the transmission curve for this filter you will see that it blocks out pretty much all of the visible spectrum except for red and beyond. Then I took a few test shots out on the street, using 8 pieces of the filter gel to make my IR images. The downside to this method is that you need to take very long exposures (ie: use a tripod), and the images are a little blurry from the thickness of plastic in front of the lens. But it definitely works. The green of the trees turns snow white after a little post processing.

street shot unfiltered thumb

street shot unfiltered desaturated thumb

street shot 8 layers red thumb

street shot 8 layers red desaturated thumb

infrared composite
N.B. The color channels of the images with the filter still contain some useful information, and if you fiddle around with them in photoshop you can get some bizarre effects. Here I have done autolevels and then swapped the red and blue channels (you do this with the “channel mixer” tool in PS).
infrared shot rb swap thumb

Posted by dylan under machines | 3 Comments »

infrared digital camera part 1

September 28th 2007

Dark Tree by Zach Stern
Infrared photography a fun way to create some interesting and unusual images, like these. Photographs of outdoor scenery are the most impressive, where trees and grass look bright white instead of green (chlorophyll is transparent to infrared light). Once upon a time, the only way to take pictures in infrared was to use a 35mm camera loaded with special film, but nowadays you can modify any digital camera to capture infrared relatively easily.

I found this set of instructions for how to modify a digital camera and I thought I’d give it a shot. In principal all you have to do is remove the IR blocking filter from behind the lens, and put in some red plastic gel lighting filters in its place. But in reality, taking apart a digital camera involves working with a lot of miniscule screws and very fragile components, and there’s a high probability you will ruin your camera forever if you mess up even slightly. Options to consider are 1) paying a professional hundreds of dollars to modify your camera for you, like this place, or 2) practicing on a really cheap camera so that you won’t cry when you turn it into a brick.
25 dollar camera
I chose option 2. I went to Fry’s and picked up the cheapest digital camera I could find. This item here set me back a cool $24.99. Don’t be fooled by its stylish appearance. It’s 100% plastic and would probably disintegrate into a million pieces if you sneezed on it. It came in a big piece of plastic packaging along with a “digital photography for dummies” book and a CD full of dubious-looking software. The software was only for PC and it was unclear whether the camera would work with my shiny macintosh without it. But it was USB, so I figured there was a good chance it would just mount when I plugged it in, and I could pull off the images.
digital camera with book
I got it home and took two pictures of my feet, then plugged it into my computer. Alas, it didn’t mount. I’ve since returned it (my apologies to the next person who may buy the camera and find it loaded with pictures of my feet, there was nothing I could do). The quest to find a disposable digital camera goes on. While I was in the camera department of Fry’s a feeling overtook me, which I can only describe as megapixel-related-depression. My current “nice” digital camera is a Canon PowerShot S30 that was state of the art when I got it back in 2002. Now its 3.2 megapixels are easily outshined by even the cheapest digicam (of the ones that don’t come in plastic packaging).

Posted by dylan under machines | 3 Comments »