In this paper, a dual-band (visible light and SWIR) observation and imaging optical system is proposed. The system can acquire the optical characteristics of the target in the range of 900nm-1700nm by imaging. SWIR imaging not only can get the infrared characteristics of the target, but also has the ability of anti-camouflage and through-fog. It makes up for the deficiency of visible light imaging. The integrated system of visible light and SWIR can be widely used in military monitoring, forest fire prevention, geodesy and other fields, and has high practical values. The integrated system shares the front group of telescopic objective and shares the field of view. The visual observation system working in the visible band, the diameter of the entrance pupil is 24mm, the diameter of the exit pupil is 6mm, the distance of the exit pupil is more than 20mm, and the visual magnification is-4<sup>×</sup> . The SWIR imaging system working in 900nm-1700nm, and the diameter of the pupil is 24mm, and the focal length is 117.3mm. The field of view is for the two systems. The design and analysis results show that the system has dual-channel imaging of visible light and SWIR with common field of view, which can obtain clear visual images and digital images. The quality of the visual system and the imaging system meet the needs.
Due to the extra wide field of view, fisheye optical systems are appropriately applied in space camera for scouting large-scale objects with near-distance. At the same time, because of the violent sunlight linger within the field of view more than other optical system and more stray light occur during the period, to design proper lens-hood can effectively reduce the sunshine time. Another distinct characteristic of fisheye optical system is the first protrude lens, which is contrived with negative focus to trace the ray with angle about even above 90 degree of incidence. Consequently, the first lens is in danger of damaging by scratching when operating the camera during the ground experiments without lens-hood. Whereas on account of the huge distortion which is the third mainly characteristic of fisheye optical system, to design appropriate lens-hood is a tough work comparing with other low-distortion optical system, especially for those whose half diagonal field is more than 90°. In this paper, an research carried out on the design lens-hood for fisheye is proposed. In the way of reverse ray-tracing, the location on the first lens and point-vector for each incident ray can be accurately calculated. Thus the incident ray intersecting the first lens corresponds to the boundary of the image sensor form the effective object space. According to the figure of the lens and the incident rays, the lens-hood can be confirmed. In the proposed method, a space fisheye lens is presented as a typical lens, whose horizontal field and vertical field are 134°, diagonal field is up to 192°, respectively. The results of design for the lens-hood show that the lingering time of sunshine is shorten because of obstructing some redundant sunlight, and the first outstanding lens are protected in the most degree.
Following with the “high-resolution upsurge” appeared in many counties in recent few years, it is an inevitable trend to increase the size of the Optical Telescope. However, because of the volume constrains of space-borne astronomical instruments, segmented reflector is thought as the main measure of future astro-physical missions by many scientists. In this paper, a coaxial three-mirror anastigmatic system (TMA) with a segmented primary mirror is modeled in optical software. The optical system, which has 2.4m aperture, 48m focal length and the field-view angle of 0.3°×0.06°, works in the 450nm~900nm wave band. The ‘1+6’ aperture-stiching model is applied. Firstly, the initial structure of the system is inputted to the CODEV, and a certain constraint functions are set, and then the system automatically optimizes. Finally, designing results show that the Modulation Transfer Function (MTF) is really very near to the limit of diffraction. We get a good image quality of the optical system design results.