Multi-fibre calibration of incoherent optical fibre bundles for image transmission

Abstract

This paper presents a multi-fibre illumination technique for automatically calibrating incoherent optical fibre bundles to enable the transmission of optical images. The calibration system consists of a host computer, a T414 Transputer board, a dedicated calibration board, a CCD camera, two TV monitors, and an incoherent optical fibre bundle. Multiple light spots produced on the screen of a TV monitor are used as a light source to illuminate simultaneously many input fibres in the bundle. The position of the corresponding output fibres can be found by capturing and analysing the image recorded by a CCD camera. Three incoherent optical fibre bundles with different resolutions have been calibrated using this technique and verified by transmitting several different types of picture. The reconstructed image is achieved by means of a dedicated calibration board operating in nearly real time mode, i e within a delay time of one field period of 20 ms from the capture of the image. From the experimental results, the adequate transmission of images by an incoherent optical fibre bundle is clearly shown to be possible. The disadvantage of the long calibration time required by the single-fibre calibration method has been overcome by using this new technique.