Compact wide-angle capsule endoscopic lens design

Abstract

Capsule endoscopes require a high-quality imaging system in terms of the wide field of view (FOV), image brightness, and resolution to provide accurate diagnostic information. However, because of the wide-angle lens design, the first element of the lens inevitably becomes larger in diameter, making it difficult to reduce the overall size of the lens. In this study, the compact wide-angle lens for a capsule endoscope is reported. The proposed system allows the first element to be compact in diameter and increases image quality by utilizing all aspheric surfaces for optical aberration control. The specification of the proposed capsule endoscope lens shows the wide FOV of 160 deg, F-number 2.8, and total track length of 5 mm. In the overall FOV, relative illumination is still over 60%. To achieve a high image quality in the proposed system, the modulation transfer function is over 30% at 180 lp/mm for a 1920 × 1080 1/6 inch CMOS image sensor in a pixel size of 1.4 µm.

Optical System Design for Micro Medical Electronic Endoscope

“…From Table IV, we can find that our FOV is the smallest compared to other results, but for endoscopes, under other key indicators, we use the least number of lenses, only 4 units, to meet the simple structure. While ensuring image clarity and an expanded field of view, the optical system of the endoscope can be reduced in size and made easier to process, thus improving the imaging technique and results [20]. A new electronic endoscope optical system with just 4 lenses and a compact structure has been designed.…”

“…At the same time, it can maintain a high resolution and frame rate, and has broad development prospects in the future of painless diagnosis. Under the condition of non-invasive and anesthesia free inspection, the outer diameter of the front end of the instrument is required to be no more than 8 mm [7,8] and most of the conventional endoscopes in existing hospitals exceed this limitation. At the same time, the front end also integrates with imaging systems, illumination systems, and other channels with special functions, hence, the outer diameter of the imaging system has more demanding requirements [9].…”

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

“…In this Letter, a small distortion is achieved, while the distortion would not affect the imaging clarity of the RFIS. The distortion analysis of the RFIS was done according to Standard Mobile Imaging Architecture (SMIA) TV distortion, which is given by [29,30] SMIA TV distortion % = h 0 − h=h × 100, where h 0 denotes the half-height at the image corner, and h represents the halfheight on the center. Maximum SMIA TV distortion is −15%.…”