Analogue motion estimation based upon a squaring circuit

Abstract

Motion estimation (ME) is the most computationally demanding part of the digital video coding process. The use of analogue computational circuits in this application can offer reductions in size and power dissipation. However, analogue circuits are subject to variations which can reduce performance. In this paper the analogue non-idealities are considered, and results are presented for video conferencing applications. Furthermore, a compact MOS squaring circuit for use in analogue ME processors is proposed. The circuit makes use of the inherent square-law characteristic of the MOS transistor in saturation and features small area, low-power and low-voltage operation. Measurements from fabricated samples of the circuit were incorporated in system-level simulations. The results of the simulations confirmed the suitability of the circuit for the intended application.