A DIGITAL VISION SENSOR

This paper presents a monolithic 128 x 128 pixel optical sensor with a nalog-to-digital converters, control and interface circuits designed s pecifically for direct connection to a host processor. The structure o f the sensor leads to a reduction in the global complexity of the imag e-acquisition hardware and to the replacement of the noise-prone analo g line between sensor and host computer. Simplicity of use is maximize d thanks to the encapsulation of all the critical analog components wi thin the chip. The key to the high integration level of the sensor is its implementation in standard CMOS technology, which offers the possi bility of integrating signal-conditioning and interface functions on t he same die as the sensor array and dispensing with the complex clocki ng schemes at non-standard voltages required by conventional CCD senso rs. Several features convenient in many machine-vision applications ar e included: square pixels, non-interlaced operation, adjustable sensit ivity to light, acquisition of a frame of data on demand and extractio n of a region-of-interest by addressing a sub-block of the complete ar ray. A complement of registers is included to control the operational parameters: integration time, analog-to-digital converter resolution a nd the coordinates of the region of interest. Single 5 V operation is provided. The sensor is fabricated in a 2 mu m CMOS process and its fu nctionality at up to 25 frames s(-1) has been demonstrated.