Design of a real-time fiber-optic infrared imaging system with wide-angle and large depth of field

A key limitation in the observation of instruments used in operations and heart sutures during a procedure is the scattering and absorption during optical imaging in the presence of blood. Therefore, we propose a novel real-time fiber-optic infrared imaging system simultaneously capturing a flexible wide field of view (FOV) and large depth of field infrared image in real time. The assessment criteria for imaging quality of the objective and coupling lens have been optimized and evaluated. Furthermore, the feasibility of manufacturing and assembly has been demonstrated with tolerance sensitivity and the Monte Carlo analysis. The simulated results show that the optical system can achieve a large working distance of 8 to 25 mm, a wide FOV of 120°, and the relative illuminance is over 0.98 in the overall FOV. To achieve high imaging quality in the proposed system, the modulation transfer function is over 0.661 at 16.7 lp/mm for a 320×256 short wavelength infrared camera sensor with a pixel size of 30 µm.