Continuous wave diffuse optical tomography using multimode plastic fiber for non-destructive test of diffused material

A simple hardware system of continuous wave diffuse optical tomography (CW DOT) is proposed and demonstrated for non-destructive test using multimode plastic fiber. The multimode plastic fiber transmits a signal that is scattered and captured by the receiver. The system consists of a near infrared (NIR) light source, a mechanical rotation stage for the object and detector, a silicon detector, a set of fiber, a driver for the data acquisition system and computerized data analysis software. The NIR with wavelength of 808 nm is launched onto the object surface and the scattered signal is collected by a set of fiber. The object is put on a mechanical rotation stage, which consist of 16 holes for light transmission and reception, respectively. A fiber probe for the acquisition of the received signal is connected to the mechanical rotation stage for the detector. The mechanical rotation stage for the object and detector can both be rotated and controlled by a data acquisition system driver. A simple CW DOT hardware system is used to scan an object. The object used in the experiment is a circle of homogeneous polyvinyl chloride and an anomaly which is inserted into the homogeneous object. The intensity of the scattered signal from various positions of the source-detector pair is reconstructed by a linear single step reconstruction. The stability of the rotation mechanical stage for the object and detector are tested and show that the rotation stage have high stability. The results of the image reconstruction show that this system can be used for scanning an object which has the same image reconstruction as the original object. Therefore, the developed CW DOT system has been successfully constructed.