In the aerial photogrammetry, the position and attitude information of the aerial camera at the time of exposure can be obtained through the positioning and orientation system carried on board, which is introduced into the collinear equation to solve the geodetic coordinates of the target points, and the direct geographic positioning can be completed and positioning the lever arm of directional system will bring the output error, resulting in collinear equation of deviating from the collinear condition, thus affecting the precision of the target for the quantitative analysis of the lever arm effects on the accuracy of positioning and orientation system, this paper analyzes the inertial measurement unit under different installation method of the lever arm type, use the data analysis of two kinds of semi-physical simulation installation effect the precision of the system, in when the pendulum is swept at 60 degrees, the attitude error is about 0.01. According to the results, the error compensation model of the lever arm is established, which provides a theoretical basis for compensating the influence of the lever arm error.
In order to meet the needs of TV detection in deep sea environment, a compact continuous zoom system driven by cam sleeve is studied. Through the analysis of the system indicators, the optical system of three groups of linkage zoom and rear group for focusing is selected, and the structure of cylindrical cam driving to cooperate with the cylindrical guide sliding is clarified. Based on this idea, each module of the TV detection system is designed in detail. The design method of electric iris diaphragm in the middle of the system is proposed, and the calculation process and results of zoom drive mechanism selection are given. The method of alignment of lens optical axis adjustment with theodolite and cross-reticle is put forward. With this design and adjustment process, the TV detection system can be applied to deep sea environment is finally realized. The system has a continuously variable field of view with 5.8°~60° underwater, the F number changes from 3.5 to 16, and the whole zoom time is less than 2s. The test results show that the MTF of the center field of view at the long focal point and the short focal point are 0.4 and 0.57. Test images in laboratory and underwater scene are clear and high resolution, which shows that the imaging quality of the system is excellent. At the same time, the system is Φ 105×115mm in actual size and 860g in weight, and can be integrated into the deep-sea pressure cabin to meet the needs of deep-sea detection.
Aiming at the threats to spacecraft safety caused by space debris, and improving the stability and working life of spacecraft in orbit, it is proposed to use spacecraft equipped with a safety self-perceptual optical payload to detect space debris to improve the safety of the aircraft in orbit. This paper analyses the application methods and characteristics of the safety self-perceptual optical payload of space vehicles, and defines the technical indicators of the optical payload. The safety self-Perceptual optical payload includes the MWIR optical system with large field of view and the visible continuous zoom lens with large zoom ratio. The detector resolution is 1280×1024, the pixel size is 15μm, the focal length is 8mm, the F number is 2, and the field of view is 97.6°×85° of MWIR optical system;The detector resolution is 1920×1080, the pixel size is 5.5μm, the focal length is 15mm~750mm, which has a 50 times zoom ratio, and the field of view is 38.8°×22.4°~0.80°×0.45° of the visible continuous zoom lens. The two systems are athermal designed in the temperature range of -40°C~60°C respectively to meet the environmental requirements of space applications. Safety self-perceptual optical payload could obtain, and apperceive long-range targets in the 10km range around the space vehicle, and improve the aircraft's survival ability
In the light of optical-electronic imaging system ,designed a continuous zoom lens with a optical aperture of 60mm and a zoom range of 18-246mm. Summarized the disadvantages of the former zoom lens and a low temperature resistant and high precision structure ,named the special-shaped slide and cam zoom structure is proposed, and carrying out the theoretical analysis and the detailed structural design. Theoretical analysis shows that this kind of structure can make the sliding friction between the cam and the main mirror tube turned into rolling friction ,thus reducing the torque demand.it also helps to eliminate the stuck phenomenon of the cam in low temperature environment .The special-shaped slide frame structure can help eliminate the tilt Angle of the moving mirror group in the zoom process ,thus reducing the variation of optic axis .In the he final test, the zoom time is not longer than 8s in the environment which temperature is only -45°C,and the variation of optic axis is smaller than 0.3milliradian,both meet the target requirement.
When the aerial camera photograph,a variety of image motion is caused by prior to the flight, pitching, rolling and vibration and other reasons,thus leading to the existence of relative motion of the illuminated objects in the focal plane of a photosensitive medium, the image is blured,and the imaging quality of the camera is seriously affected. Various causes of image motion and effects on image is analyzed by this paper,the necessity of image motion compensation is expounded. By analyzing existed methods of image motion compensation ,and on this basis, a new multi degree of freedom motion compensation method is designed,through the parallel mechanism motion,for image motion compensation by optical image motion compensation principle,a variety of airborne camera to take pictures of the image motion also can be eliminated.
Compared with visible light imaging systems, the infrared imaging systems have the advantages of strong fogging ability, especially in the high-altitude water vapor and haze environment. and the medium-wave infrared cooling detectors have the advantage of low cost compared to long waves. Therefore, in recent years, The demand for medium-wave infrared continuous zoom systems is increasing. In this design, based on the medium-wave infrared optical system, and summarizing the advantages and disadvantages of the previous zoom structure, a zoom mechanism in the form of a cam and guide was proposed. The cam mechanism, zoom guide mechanism, and compensation guide mechanism were described in detail in this paper. The detailed analysis of the torque demand during zooming was performed. Ansys workbench was used to analyze the main components of the zoom mechanism and the stray light of the system was proposed. The adjustment results show that this kind of structure can realize medium-wave infrared continuous zooming, and the the amount of optical axis shaking during zooming is less than 0.3mrad, which meets the design requirements, and the proposed stray light suppression method effectively suppresses the system's spurious radiation and improves the lens's imaging quality; impact and vibration simulation show that the strength and stiffness of the structure meet the requirements of the mechanical environment, and the imaging system has stable performance.
Thermal control and temperature uniformity are important factors for space remote sensing cameras. This paper describes the problems with existing systems and introduces the thermal design of a space optical remote sensing camera. Firstly, based on the theory of wave-front aberration distribution, the thermal control index of a space remote sensing camera is proposed. Then on the basis of the analysis of the heat flux environment outside the camera space, the thermal optical analysis of the camera is performed by using the finite element analysis method at high and low temperature conditions. The results show that the transfer function of the optical system with the resolution of 50 lp in the full field of view is more than 0.4. The optical design index can be satisfied, and the rationality of the thermal design is verified. The simulation result meets the requirements of optical design very well. Therefore the study in this paper can be used as an important reference for other space optical systems, which has certain engineering significance.
This paper proposed a new algorithm of inter-frame filtering in IR image based on threshold value for the purpose of solving image blur and smear brought by traditional inter-frame filtering algorithm. At first, it finds out causes of image blur and smear by analyzing general inter-frame filtering algorithm and dynamic inter-frame filtering algorithm, hence to bring up a new kind of time-domain filter. In order to obtain coefficients of the filter, it firstly gets difference image of present image and previous image, and then, it gets noisy threshold value by analyzing difference image with probability analysis method. The relationship between difference image and threshold value helps obtaining the coefficients of filter. At last, inter-frame filtering method is adopted to process pixels interrupted by noise. The experimental result shows that this algorithm has successfully repressed IR image blur and smear, and NETD tested by traditional inter filtering algorithm and the new algorithm are respectively 78mK and 70mK, which shows it has a better noise reduction performance than traditional ones. The algorithm is not only applied to still image, but also to sports image. As a new algorithm with great practical value, it is easy to achieve on FPGA, of excellent real-time performance and it effectively extends application scope of time domain filtering algorithm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.