From V1SH to CPD : A New Framework for Understanding Vision

Zhaoping Li
Head of Sensory and Sensorimotor Systems, Max Planck Institute for Biological Cybernetics, Germany

Thursday 18 March at 13:00 GMT


V1SH is the V1 Saliency Hypothesis, and CPD is the Central-Peripheral Dichotomy. I will explain how they motivate a new framework: Visual attention selects only a tiny fraction of visual input information for further processing.  Selection starts in the primary visual cortex (V1), which creates a bottom-up saliency map (V1SH) to guide the fovea to selected visual locations via gaze shifts. This motivates a new framework that  views vision as consisting of encoding, selection, and decoding stages, placing selection on center stage.  It suggests a massive loss of non-selected information from V1 downstream along the visual pathway.  Hence, feedback from downstream visual cortical areas to V1 for better decoding (recognition), through analysis-by- synthesis, should query for additional information  and be mainly directed at the foveal region (CPD). Accordingly, non-foveal vision is not only poorer in spatial resolution, but also more susceptible to many illusions.  Some background/details are in this link http://www.lizhaoping.org/zhaoping/NewPathPaperEtc_2019.html . I will also show the latest findings, including a peripheral illusion predicted by this framework and a stereo vision paradigm as an example to investigate the analysis-by-synthesis process in the top-down feedback for visual inference in central vision.