Time division ghost imaging.

In the conventional ghost imaging, it requires to illuminate a large number of patterns in order to reconstruct a good quality image under a low signal-to-noise ratio. We propose a new method so called time division ghost imaging to improve the quality of the image in noisy environment. In this procedure, the total number of patterns in the calculation process of the correlation function are divided into the sub-units with fewer illuminated patterns. Then one calculates the correlation for each sub-unit, and synthesizes the intermediate images obtained at each sub-unit. The validation and effectiveness of this method are confirmed by simulation and experiment, showing the robustness to noise.

Measurements of glucose concentration in aqueous solutions using reflected THz radiation for applications to a novel sub-THz radiation non-invasive blood sugar measurement method.

The terahertz (THz) frequency range corresponds to molecular vibrations or relaxation modes such as those for the hydrogen bond. Most biomolecules are activated only in aqueous solutions, thus, to understand the function and structure of biomolecules, it is necessary to investigate the characteristics of electromagnetic waves in hydrated samples. THz radiation causes little damage to the human body, thus it is expected that it can be applied for noninvasive examinations. However, spectrometry of the transmitted light is difficult, since the absorption of THz radiation in water is extremely high. In this study, we used sub-THz radiation (frequencies near to 0.1 THz), where the absorption is lower than for THz radiation, to measure the reflectance of a glucose water solution. We found that the reflectance decreases in proportion with the glucose concentration. These results suggest that sub-THz radiation can be used in the noninvasive measurement of blood glucose levels.