Selim Onat

I am a neuroscientist working currently on how humans make generalizations based on what they have previously learnt. To do so, I am using a variety of methodologies including fMRI (1), autonomous (2), as well as eye-movement recordings (3).

This research emanates from the well-established field of "stimulus generalization" following mainly the "lineage" of Hovland, Hull and Roger Shepard (4), and including the more recent computational work of Josua Tenenbaum (5). Furthermore, it integrates work on anxiety disorders, as it is believed that these mechanisms are impaired in people suffering from anxiety problems.

In the past, I have been working on how the nervous system processes natural scenes both at the electrophysiological and sensory-motor level. Since the times of Hubel and Wiesel, visual processing had been
overwhelmingly studied with artificial stimuli such as moving edges. However this type of stimuli suffer from an ecological validity problem, as they only rarely occur in real-life. We therefore investigated cortical processing during viewing of natural movies. This previous work focused on visual processing using mostly the technique of voltage-sensitive dye imaging and eye-tracking.

Real-Time Halftoning with Perfect Circles

How to transform an image in real-time into an array of perfect circles (or other geometrical shapes) with their diameters proportional to the local image brightness below the circle?

This is classically known as halftoning and one of the most ancient digital image manipulation methods, still used today in printing business.

I managed to do this using Quartz Composer, here is an example video. In this video, the resolution i.e. the number of circles used, changes over time. Video starts with black and white circles, continues with circles colored with original pixel values and finishes with random colored circles. It is all done in real time without any noticeable delay.


Perfect for VJing purposes. When real-timing is not necessary the content of the video can be a political figure for example...

Halftoning AngelaMerkel from sonat on Vimeo.

The concept can be generalized to other politicians or other half-toning shapes...

Halftoning Politicians from sonat on Vimeo.

Halftoning AngelaMerkel Hearts from sonat on Vimeo.

Cross modal integration with auditory modality could be implemented by adding a noise to the diameter of the circles that is proportional to the amplitude of the instantaneous sound signal..