A real-time color space converter for the measurement of appearance

The value of being able to specify and control color representations in per ceptual ter terms is increasingly being recognized. The advantages of using perceptual color spaces include intuitive addressability, uniformity, inde pendent control of lightness and chromatic contrast, and device characteriz ation in perceptual terms. This paper presents the design and VLSI implemen tation of a new digital hardware structure which performs the conversion, i n real-time, of the R, G and B color co-ordinates to the CIE L*u*v* percept ually uniform color space. For a typical 512 x 512 pixel digital color imag e the number of required operations is 28 x 512(2) (including, power and di vision operations) and these cannot be executed in software fast enough to cope with time critical applications. The high speed of operation is achiev ed by pipelining the data in a vector fashion. The structure is implemented using a DLM, 0.7 mum, N-well, CMOS process provided by the European Silico n Structures (ES2), and it occupies a silicon area of 6.40 mm x 6.60 mm = 4 2.24 mm(2). Its maximum speed of operation is 20 MHz and its throughput rat e of operations is 260 MIPS. Targeted applications include display device m odeling, device independent color reproduction, colorimetry instrumentation , Virtual reality, and color machine vision applications. (C) 2001 Pattern Recognition Society. Published by Elsevier Science Ltd. All lights reserved .