Basic Concept of Ophthalmology and Visual Disorder

The eye is a complex sensory organ that is responsible for vision. Within the protective sheath, each eye has receptors, a lens system for focusing light on receptors, and a nervous system for transmitting impulses from the receptors to the brain. Visual dysfunction can be caused by abnormal eye movements or changes in visual acuity, refraction, color vision, or accommodation. Visual dysfunction may also be a secondary effect of other neurological disorders. This narrative review aims to describe the structure of the eye in general and visual disturbances caused by the aging process and disorders of the protective structure of the eye.

Intelligent Fuzzy Focusing System For Dark Channel Image Based On Ratio Constraint

The starting point of the establishment of the optimized dark channel algorithm is to stabilize the contrast of the two parts of the image (light and dark). The first step of this method is to divide the initial image into two suitable light and dark parts, and then to obtain the contrast data between the two parts, and the second step is to solve the dark area according to the above optimized operation principle. The third step is to exert its accurate management bright features to the extreme to ensure its contrast stability through the operation of double histogram equalization. Modify the unreasonable arrangement of brightness. Take the CCD or CMOS image sensor as an example, the reference will be shown in the above example according to the lens system, and then the intelligent chip of the non-manually operated focusing device will complete the next processing, transmitting the discrimination result to the front system through the motor, and finally focusing. The intelligent fuzzy focusing is composed of the upper and lower computers, the former is the module of collating, collecting materials and processing all the data, the latter is the management and control module of the evaluation results, and the communication part provides communication for the two. Finally, it can be seen that the optimized dark channel algorithm is obviously better than the de-fog algorithm in terms of the effect of information entropy, brightness and average gradient, which makes the detailed characteristics of being obscured by fog more obvious.

Design and Experimental Implementation of a Multi-Cloak Paraxial Optical System

Electromagnetic cloaking has being continuously pursued using a large variety of approaches. In recent years, this effect has been observed using either complex devices based on the so-called Transformation Optics or simple systems based on conventional optics with proper characteristics. In the latter case, a simple arrangement of lenses working in the paraxial regime can provide broadband visible cloaking in a wide area. In this work, we analyzed and generalized this method by proposing a five-lens system producing at least three potential invisible regions with a large cloaked area (>90% of the visual field). In particular, we developed the mathematical formalism and show, both numerically and experimentally, the successful operation of the cloaking system with the naked eye.

A NEW METHOD OF LENS CENTERING IN THE OPTICAL SYSTEM BY USING SPECIAL MOUNT

Decentration in lens systems (for example objectives) significantly degrades the quality of image, such as the coma. In order to reduce lens decentration, the lenses are centered while manufacturing, while gluing, while attachment in the mounts. Significant decrease in the lenses decentering in the mounts is achieved by using a special manufacturing equipment, which allow combining the optical axis of the lens with the base axis of the mount in assembly process. Solutions for coma's alignment by shifting, tilting and rotation their components are also provided in the construction of high-quality objectives (microscopes [1-7], photolithographic, aerophotographic). For optimization of methods for such adjustment the influence coefficients of decentering of each optical surface of the lens system on the value and sign of coma must be calculated and taken into account. In this paper, we propose a special mounting which combined with the Opticentric of Trioptics device to center the lenses. The results show that the decentering is significantly reduced (0.9µm) compared to (44.2µm) with using a reference mount.

Design of Refractive/Diffractive Hybrid Projection Lens for DMD-Based Maskless Lithography

The projection lens is the core component of DMD-based maskless lithography and its imaging quality directly affects the transferal of exposure pattern. Based on the traditional projection lens system, we have designed diffractive optical element (DOE) and aspheric surfaces to optimize the refractive/diffractive hybrid projection lens system to improve its imaging quality. We found that the best effect is obtained when DOE is very close to the front lens group before the diaphragm of the hybrid system. Compared with the traditional projection lens system, this hybrid projection lens system has lower wave aberration with the help of DOE, and higher image quality owing to the modulation transfer function (MTF) value being improved. Finally, a hybrid projection lens system with working distance of 29.07 mm, image Space NA of 0.45, and total length of 196.97 mm is designed. We found that the maximum distortion and field curvature are 1.36 × 10−5% and 0.91 μm, respectively.

PARAXIAL SYNTHESIS OF LWIR CONTINUOUS ZOOM LENS SYSTEM

Trends in the development of IR lens systems, possible problems and solutions arising in the development of LWIR variofocal lens systems interfaced with uncooled matrix receivers, company products and the characteristics of the lens systems they produce are considered. The analysis of the considered products has been carried out, as a result of which the most optimal characteristics for development have been identified. The aim of the study is to obtain in the paraxial approximation a mathematical model of a variofocal LWIR objective coupled with an uncooled matrix receiver, and to identify the relations in such a model. The research results will be used for further theoretical and practical research in the master thesis.