Low-power 8-valued cellular array VLSI for high-speed image processing

This paper presents a low-power 8-valued cellular array VLSI for high-speed image processing based on logical neighborhood operations with 3×3 windows. This array is useful for performing low-level image processing such as noise removal and edge detection, in intelligent integrated systems where immediate response to input change as well as high throughput is needed. In order to achieve high-speed image processing, template matching for neighborhood operations can be performed in parallel on each row. Each row of the image is operated in a pipelining manner. The direct 8-valued encoding of the matched results for three different 3×3 masks makes it possible to reduce the number of operations by one-third. In the hardware implementation, the matching cell for logical neighborhood operations can be implemented compactly using MOS transistors with different threshold voltages, which are programmed by multiple ion implants. Moreover, a new literal circuit for detecting multiple-valued signals using a dynamic design style eliminates hazards due to timing skews in the difference of various input voltage levels, so that the dynamic power dissipation of the proposed circuit is greatly reduced. Finally, it is demonstrated that the processing time of the proposed cellular array is reduced to about 40 percent in comparison with that of a corresponding binary circuit when power dissipation/area = 0.3 W/100 mm².