|COOKIES: By using this website you agree that we can place Google Analytics Cookies on your device for performance monitoring.|
Learning transformational invariants from natural movies
If you have a question about this talk, please contact Rachel Fogg.
A key attribute of visual perception is the ability to extract invariances from visual input. Here we focus on transformational invariants – i.e., the dynamical properties that are invariant to form or spatial structure (e.g., motion). We show that a hierarchical, probabilistic model can learn to extract complex motion from movies of the natural environment. The model consists of two hidden layers: the first layer produces a sparse representation of the image that is expressed in terms of local amplitude and phase variables. The second layer learns the higher-order structure among the time-varying phase variables. After training on natural movies, the top layer units discover the structure of phase-shifts within the first layer. We show that the top layer units encode transformational invariants: they are selective for the speed and direction of a moving pattern, but are invariant to its spatial structure (orientation/spatial-frequency). The diversity of units in both the intermediate and top layers of the model provides a set of testable predictions for representations that might be found in V1 and MT. In addition, the model demonstrates how feedback from higher levels can influence representations at lower levels as a by-product of inference in a graphical model.
Joint work with Charles Cadieu.
This talk is part of the Signal Processing and Communications Lab Seminars series.
This talk is included in these lists:
Note that ex-directory lists are not shown.
Other lists"Postdoc Masterclass" for All Life Scientists European Research Seminar Series 2015-2016 Cambridge Café Scientifique
Other talksMEMS mode-localized resonant sensors based on three weakly coupled resonators Annual Conversazione: Cambridge’s oldest celebration of citizen science! Cosmology with the Baryon Oscillation Spectroscopic Survey (BOSS) Dr Francois Legoux: CD4+ T cell tolerance to self-antigens Perturbation Analysis of LEAFY in the Floral Transition Network of Arabidopsis thaliana Resonances and streaming of an Armoured Microbubble