No abstract

Application of cell-phone-based microscopes has been hindered by limitations such as inferior image quality, fixed magnification and inconvenient operation. In this paper, we propose a reverse cell phone lens-based miniature microscope with a configurable magnification ratio. By switching the objectives of three camera lens and applying the digital zooming function of the cell phone, a cell phone microscope is built with the continuously configurable magnification ratio between 0.8×–11.5×. At the same time, the miniature microscope can capture high-quality microscopic images with a maximum resolution of up to 575 lp/mm and a maximum field of view (FOV) of up to 7213 × 5443 um. Furthermore, by moving the tube lens module of the microscope out of the cell phone body, the built miniature microscope is as compact as a <20 mm side length cube, improving operational experience profoundly. The proposed scheme marks a big step forward in terms of the imaging performance and user operational convenience for cell phone microscopes.

A harsh environment-oriented distributed multipoint fiber optic gas sensor system realized by automatic gain control (AGC) technology is proposed. To improve the photoelectric signal reliability, the electronic variable gain can be modified in real time by an AGC closed-loop feedback structure to compensate for optical transmission loss which is caused by the fiber bend loss or other reasons. The deviation of the system based on AGC structure is below 4.02% when photoelectric signal decays due to fiber bending loss for bending radius of 5 mm, which is 20 times lower than the ordinary differential system. In addition, the AGC circuit with the same electric parameters can keep the baseline intensity of signals in different channels of the distributed multipoint sensor system at the same level. This avoids repetitive calibrations and streamlines the installation process.