General-purpose 128 128 SIMD processor array with integrated image sensor

Introduction: In some computer vision applications, especially where high computational performance is required together with low power consumption, it is beneficial to use ‘vision chips’—devices that combine image sensing and processing on a single silicon die. Application-specific vision chips can efficiently perform some uncomplicated low-level image processing tasks, such as filtering, edge detection, or motion detection, often using analogue circuitry operating in pixel-parallel fashion. But to combine different operations to form a more complex algorithm, and to provide flexibility to use a chip for various algorithms, a software-programmable solution must be employed. The required flexibility can be provided by general-purpose SIMD processor arrays. We have been working towards combining the two paradigms: a general-purpose SIMD array and analogue processor-per-pixel vision systems [1–3]. Our first proof-of-concept ‘analogue SIMD vision chip’ [1] (SCAMP— switched current analogue matrix processor), was a 21 21 processor array. An improved, 39 48 chip version (SCAMP-2) was subsequently developed [2] followed recently by a 128 128 (SCAMP-3) device [3]. In this Letter we overview the SCAMP-3 chip design and present measured performance=accuracy data and experimental image processing results.