Tag: vision

July 31, 2010

Radiolab: Strangers in the Mirror
Visit the source: blogs.wnyc.org

Another excellent short episode of Radiolab, featuring a conversation with two people I wouldn’t expect to hear on stage together:

Oliver Sacks, the famous neuroscientist and author, can’t recognize faces. Neither can Chuck Close, the great artist known for his enormous paintings of … that’s right, faces.

Oliver and Chuck–both born with the condition known as Face Blindness–have spent their lives decoding who is saying hello to them. You can sit down with either man, talk to him for an hour, and if he sees you again just fifteen minutes later, he will have no idea who you are. (Unless you have a very squeaky voice or happen to be wearing the same odd purple hat.)

If you’re interested in the science of face perception, I stumbled across this relevant paper this week: Cortical Specialization for Face Perception in Humans (pdf) co-authored by Tel Aviv University’s Galit Yovel.

faces, npr, perception, radiolab, science, vision
July 4, 2010

Structured Light

Real-time 3D capture at 60fps using a cheap webcam and simple projected pattern of light points. The structured-light code is open source, looks like a pretty cool project.

(Via Make)

3d, graphics, light, open source, vision, visualization, webcam
June 11, 2010

Iphone Resolution

Phil Plait of Bad Astronomy lucidly explains display resolution, clearing up arguments about the iPhone 4’s retinal display technology:

Imagine you see a vehicle coming toward you on the highway from miles away. Is it a motorcycle with one headlight, or a car with two? As the vehicle approaches, the light splits into two, and you see it’s the headlights from a car. But when it was miles away, your eye couldn’t tell if it was one light or two. That’s because at that distance your eye couldn’t resolve the two headlights into two distinct sources of light.

The ability to see two sources very close together is called resolution.

DPI issues aside, the name “retinal display” is awfully confusing given that there’s similar terminology already in use for virtual retinal displays…

apple, display, eyes, graphics, iphone, resolution, technology, vision
June 2, 2010

Digital Quantification of Human Eye Color
Visit the source: www.plosgenetics.org

For those of you with eyes that aren’t easily categorized as simply “brown”, “blue”, or “hazel”: researchers have written up a new genetic model for human eye color phenotyping, published in PLoS Genetics.

We measured human eye color to hue and saturation values from high-resolution, digital, full-eye photographs of several thousand Dutch Europeans. This quantitative approach, which is extremely cost-effective, portable, and time efficient, revealed that human eye color varies along more dimensions than the one represented by the blue-green-brown categories studied previously. Our work represents the first genome-wide study of quantitative human eye color. We clearly identified 3 new loci, LYST, 17q25.3, TTC3/DSCR9, in contributing to the natural and subtle eye color variation along multiple dimensions, providing new leads towards a more detailed understanding of the genetic basis of human eye color.

(Via Nature)

anatomy, color, eyes, genetics, science, vision
January 17, 2010

John Balestrieri’s Generative Painting Algorithms

John Balestrieri is tinkering with generative painting algorithms, trying to produce a better automated “photo -> painting” approach. You can see his works in progress on his tinrocket Flickr stream. (Yes, there are existing Photoshop / Painter filters that do similar things, but this one aims to be closer to making human-like decisions, and no, this isn’t in any way suggestive that machine-generated renderings will replace human artists – didn’t we already get over that in the age of photography?)

Whatever the utility, trying to understand the human hand in art through code is a good way to learn a lot about color theory, construction, and visual perception.

(Via Gurney Journey)

art, color, graphics, photography, programming, research, vision
January 10, 2010

Face Detection
Visit the source: gurneyjourney.blogspot.com

My camera switches over to portrait-mode whenever it sees a painting or a drawing with a face in it. It stays in AUTO mode otherwise.

According to Popular Mechanics: “a chip inside the camera constantly scans the image in its viewfinder for two eyes, a nose, ears and a chin, making out up to 10 faces at a time before you’ve hit the shutter.”

I decided to test my camera—it’s a Canon Powershot SX120—to see what it decides to regard as a face.

Artist James Gurney tests out his point-and-shoot’s facial recognition chip against works of art and illustration. A mixed bag, but a good reminder that this technology is getting better and cheaper (and subtle) all the time.

art, graphics, imaging, technology, vision
December 22, 2009

Magician Marco Tempest Demonstrates a Portable AR Screen

Magician Marco Tempest demonstrates a portable “magic” augmented reality screen. The system uses a laptop, small projector, a PlayStation Eye camera (presumably with the IR filter popped out?), some IR markers to make the canvas frame corner detection possible, Arduino (?), and openFrameworks-based software developed by Zachary Lieberman. I really love this kind of demo – people on the street (especially kids) intuitively understand what’s going on. This work reminds me a lot of Zack Simpson’s Mine-Control projects, especially with the use of cheap commodity hardware for creating a fun spectacle.

(Via Make)

Augmented reality, graphics, openframeworks, programming, video, vision
December 21, 2009

MyDsReader: Nintendo DS Text-to-Speech

MyDsReader, Nintendo DS text-to-speech document reading software for the visually impaired. It’s using the Flite synthesis engine designed for embedded devices, implements gesture controls for ease of use and even throws in an integrated email and to-do client. Excellent use of homebrew development.

(Via GameSetWatch)

accessibility, hacking, homebrew, nintendo, nintendo ds, pdf, programming, text to speech, video, vision
December 11, 2009

A biological quarter-wave retarder with excellent achromaticity in the visible wavelength region
Visit the source: www.nature.com

A paper in Nature Photonics describing the waveplate mechanism found in the eye of mantis shrimp (stomatopods). These amazing critters can see hyperspectral color ranging from the infrared to the ultraviolet, can perceive different planes of circular polarized light, and have eyes that operate and dart about (saccade) independently. This paper is basically demonstrating that man-made material science has a lot to learn if we want to catch up with nature’s technology.

Personal side question: what are these shrimp on the lookout for that’s led to such a sophisticated eye??

color, nature, perception, physics, science, vision
September 12, 2009

Binocular Diplopia and the Book of Kells

How did reclusive monks living in the year 700 or 800 AD draw the intricate lines of the Book of Kells, rendered by hand at sub-millimeter resolution (about the same level of detail as the engraving work found on modern money), hundreds of years before optical instruments became available, hundreds of years before the pioneering visual research of Alhazen? According to Cornell paleontologist John Cisne’s theory, their trick was in the detail and pattern: by keeping their eyes unfocused on the picture plane, the monks could superimpose their linework and judge the accuracy against the template using a form of temporary binocular diplopia (sort of like willing yourself to view a stereograph or one of those Magic Eye posters).

That’s amazing.

art, book of kells, history, ireland, optics, research, science, vision