An adaptive visual tracking sensor with a hysteretic winner-take-all network

We present a CMOS VLSI image sensor containing a 26×26 array of differentiating adaptive photoreceptors, combined with a current-mode hysteretic winner-take-all (WTA) network, able to detect and track high-contrast targets moving within its field of view. The device, implemented using standard 0.8 μm CMOS technology, dissipates 600 μW, with a power supply voltage of 5 V. Its WTA outputs can be read out using either analog position-to-voltage circuits, or digital address encoders. Photoreceptor voltages with sustained and transient responses can be read out serially using an on-chip scanner, or in a random-access mode using address decoders. Combining digital output position encoders and input address decoders, it is possible to read only the location of the winning pixel, or a small window around the winning pixel (e.g. using a microcontroller), thus implementing a selective attention read-out mechanism.