An Innovative Wireless Endoscopic Capsule With Spherical Shape

This paper aims to contribute to the advancement of the Wireless Capsule Endoscopy (WCE) field for ColoRectal Cancer (CRC) screening, by developing all electronic circuits to build an innovative wireless endoscopic capsule with a spherical shape, conceived to reduce the friction during its locomotion and thus improving patient's acceptability. The proposed capsule embeds an image sensor with optics and Light Emitting Diodes (LEDs), a control unit with a telemetry module, an actuation system, a battery with a smart recharging circuit able to recharge in 20 minutes, a smart power-on circuit and a localization module. Everything is devised to fit in a small spherical shape with a diameter of 26 mm and a weight of 12.70 g. The authors present a description of the sub-modules involved in the capsule development, together with the firmware and hardware integration. In order to reduce the bandwidth for matching the specifications of the target commercial telemetry, the firmware interfacing of a custom encoder was performed, which is able to compress the incoming images with a negligible loss of information and occupying a number of Look Up-Tables (LUTs) less than 1780. As a preliminary work, a versatile Field Programmable Gate Arrays (FPGA) based demo-board system has been developed in order to test and optimize the functionalities and the performance of the single sub-modules and wireless vision chain system. This work allows to demonstrate the feasibility of a complex biomedical system, with severe constraints by highlighting the necessity to enhance the frame rate in the future.