title: A multichip aVLSI system emulating orientation selectivity of primary visual cortical cells.
abstract: In this paper, we designed and fabricated a multichip neuromorphic analog very large scale integrated (aVLSI) system, which emulates the orientation selective response of the simple cell in the primary visual cortex. The system consists of a silicon retina and an orientation chip. An image, which is filtered by a concentric center-surround (CS) antagonistic receptive field of the silicon retina, is transferred to the orientation chip. The image transfer from the silicon retina to the orientation chip is carried out with analog signals. The orientation chip selectively aggregates multiple pixels of the silicon retina, mimicking the feedforward model proposed by Hubel and Wiesel. The chip provides the orientation-selective (OS) outputs which are tuned to 0 degrees, 60 degrees, and 120 degrees. The feed-forward aggregation reduces the fixed pattern noise that is due to the mismatch of the transistors in the orientation chip. The spatial properties of the orientation selective response were examined in terms of the adjustable parameters of the chip, i.e., the number of aggregated pixels and size of the receptive field of the silicon retina. The multichip aVLSI architecture used in the present study can be applied to implement higher order cells such as the complex cell of the primary visual cortex.
authors.affiliation: Department of Electronic Engineering, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan. kazu@ele.eng.osaka-u.ac.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shimonomura
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yagi
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D032701:Biomimetics / Q000295:instrumentation / Q000379:methods; D004581:Electronics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D009415:Nerve Net / Q000502:physiology*; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D012160:Retina / Q000502:physiology*; D012666:Semiconductors; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology