Improvement of terahertz imaging using lock-in techniques

We present results of improvement of THz images registered at the frequency of 300 GHz. The improvement is achieved by processing of both phase and magnitude information provided by lock-in amplifier. The active imager uses a continuous-wave tunable radiation source. We investigate capabilities of utilizing phase and intensity information in order to obtain more accurate shape of object. Results of processing images in order to obtain more details are shown. Improvement of the image resolution and quality by composition of selected elements of both amplitude and phase-based images using specific fusion methods is presented.