The basic neurobiology behind the 12-dot illusion

Post by kakarot » Sat, Sep 17, 2016, 4:04 PM UTC

Sharlin wrote: post #3

The fovea, the area of high-resolution vision in the middle of the field of view, is surprisingly small, just a few degrees across. The resolution falls rapidly outside the fovea [1]. A lot of the detail we perceive in the periphery is actually the brain filling in blanks based on "cached" data. The resolution drop could in principle be taken advantage of in computer graphics, especially in VR applications with robus…

Post by takatin » Sat, Sep 17, 2016, 4:17 PM UTC

kevinalexbrown wrote: post #8

I'm not sure the central argument fully explains the illusion. If you can simultaneously see several stars in the sky using your peripheral vision using averted gaze, why not several dots? I suspect uncertainty plays a part, but image completion from higher-order feedback that complete the lines might drive the illusion more. Put another way, I believe if you remove the gray lines, the illusion ceases to work.

Post by Bjartr » Sat, Sep 17, 2016, 4:23 PM UTC

dahart wrote: post #11

chakalakasp wrote: post #7

The way the eye interfaces with the brain never ceases to amaze me. Another fun fact is that it even has it's own error correction mechanisms, one of which you can intentionally miscalibrate in order to see colors that aren't there for days, weeks, and sometimes even months after doing the calibration (which is acheived by looking at a very specific image pattern for a long time). I would not recommend actually doing…

The color scientists who first told me about the McCollough effect adamantly refused to ever try it, saying it could damage your vision forever. So I was scared to try it, but eventually I did and for me the effect went away after a couple minutes. Maybe I'm lucky, but the warnings & the legend of the effect lasting months make such a good story, I have to wonder if it's a little overstated. But -- what if the effect…

Post by kevinalexbrown » Sat, Sep 17, 2016, 4:48 PM UTC

takatin wrote: post #14

kevinalexbrown wrote: post #8

I'm not sure the central argument fully explains the illusion. If you can simultaneously see several stars in the sky using your peripheral vision using averted gaze, why not several dots? I suspect uncertainty plays a part, but image completion from higher-order feedback that complete the lines might drive the illusion more. Put another way, I believe if you remove the gray lines, the illusion ceases to work.

Because stars in the sky is a high contrast visual. That applies here too, I increased the contrast using Photoshop and the illusion is gone, you can see all 12 dots perfectly fine — http://imgur.com/a/G4xR4 I think they are spot on, outside the fovea, contrast detection capability of our eyes dip drastically thereby blending the dots lying outside the fovea with the surrounding grid. Increase the contrast to the poi…

Post by socmag » Sat, Sep 17, 2016, 5:08 PM UTC

dahart wrote: post #13

socmag wrote: post #5

Earlier quoted context omitted.

Hah, why not.. We already created perceptually correct audio CODECs. Doing the same for real-time image generation seems like a worthy research area for sure!

True. And it's being done already! Here are just a few papers by my graduate school cohort. Pdiff ("perceptual diff") uses perceptual metrics including visual acuity to diff two images. This is frequently used for image based regression testing of websites. It's really handy when you need to diff images that don't come out pixel identical every time, like images made with different browsers, or images that involve so…