Implementation of a Charge Redistribution Based 2-D DCT Architecture for Wireless Capsule Endoscopy

This work proposes a charge redistribution based CMOS implementation of an ultra low power 2-D DCT architecture for wireless capsule endoscopy applications. The ultra low power operation of the proposed system is highly desirable in wireless capsule endoscopy applications, where power efficiency is critical. This technique is also suitable for other low power applications where moderate accuracy is required. In this implementation, the basic principle of charge redistribution is used to perform the low power multiply and accumulate(MAC) operation in the DCT kernel. The DCT frequency components are computed parallely, making the transform to operate at high speed. Also, a single 1-D DCT core has been reused, thanks to the separable property of the transform, which otherwise would have resulted in a much larger circuit area. The complete 8-point DCT architecture has been implemented in a 1.8 V, 0.18- μm digital CMOS technology. The performance of the implementation shows an average power consumption of 0.01 mW, a PSNR of 23.4 dB and the system occupies an active area of 0.0667 mm².