WWN-2: A biologically inspired neural network for concurrent visual attention and recognition

Attention and recognition have been addressed separately as two challenging computational vision problems, but an engineering-grade solution to their integration and interaction is still open. Inspired by the brain's dorsal and ventral pathways in cortical visual processing, we present a neuromorphic architecture, called Where-What Network 2 (WWN-2), to integrate object attention and recognition interactively through their experience-based development. This architecture enables three types of attention: feature-based bottom-up attention, position-based top-down attention, and object-based top-down attention, as three possible information flows through the Y-shaped network. The learning mechanism of the network is rooted in a simple but efficient cell-centered synaptic update model, entailing the dual optimization of Hebbian directions and cell firing-age dependent step sizes. The inputs to the network are a sequence of images, where specific foreground objects may appear anywhere within an unknown, complex, natural background. The WWN-2 regulates the network to dynamically establish and consolidate position-specified and type-specified representations through a supervised learning mode. The network has reached 92.5% object recognition rate and an average of 1.5 pixels in position error after 20 epochs of training.