BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Computational Neuroscience Journal Club - Yan Wu (University of Ca
 mbridge)
DTSTART:20131105T160000Z
DTEND:20131105T170000Z
UID:TALK48727@talks.cam.ac.uk
CONTACT:Guillaume Hennequin
DESCRIPTION:Yan Wu will cover:\nHierarchical model of natural images and t
 he origin of scale invariance\nSaeed Saremia and Terrence J. Sejnowski\n\n
 http://www.pnas.org/content/110/8/3071.short\n\nABSTRACT:\nThe study of na
 tural images and how our brain processes them has been an area of intense 
 research in neuroscience\, psychology\, and computer science. We introduce
 d a unique approach to studying natural images by decomposing images into 
 a hierarchy of layers at different logarithmic intensity scales and mappin
 g them to a quasi-2D magnet. The layers were in different phases: “cold
 ” and ordered at large-intensity scales\, “hot” and disordered at sm
 all-intensity scales\, and going through a second-order phase transition a
 t intermediate scales. There was a single “critical” layer in the hier
 archy that exhibited long-range correlation similar to that found in the 2
 D Ising model of ferromagnetism at the critical temperature. We also deter
 mined the interactions between layers mapped from natural images and found
  mutual inhibition that generated locally “frustrated” antiferromagnet
 ic states. Almost all information in natural images was concentrated in a 
 few layers near the phase transition\, which has biological implications a
 nd also points to the hierarchical origin of scale invariance in natural i
 mages.\n
LOCATION:Cambridge University Engineering Department\, CBL Rm #438 (http:/
 /learning.eng.cam.ac.uk/Public/Directions)
END:VEVENT
END:VCALENDAR