In missile applications, new counter measure methods are getting more complex. To discriminate and detect counter measure and to understand target signature from scene is getting harder. Because of all that concerns, ...
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ISBN:
(数字)9781510637719
ISBN:
(纸本)9781510637719
In missile applications, new counter measure methods are getting more complex. To discriminate and detect counter measure and to understand target signature from scene is getting harder. Because of all that concerns, using triple-mode seeker for a system solution is a good solution for system total performance. By this way, tri-different wavelength could be used for same system and same scene. In this study, triple mode system's opticaldesigns have been made for mid-wave infra-red imaging, long-wave infra-red imaging and short-wave infrared imaging. opticaldesigns performances have been illustrated in simulation results. Finally, conceptual design of triple mode seeker will be summarized.
Although considered as low level processing, edge detection is a crucial step in object and image recognition. Such an operation can be implemented in real time by use of an appropriate transmittance in the Fourier pl...
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ISBN:
(纸本)0819418994
Although considered as low level processing, edge detection is a crucial step in object and image recognition. Such an operation can be implemented in real time by use of an appropriate transmittance in the Fourier plane of a so-called VanderLugt optical correlator. The performance of this scheme depends on both the contour enhancement operator chosen and the spatial filter design. For the latter point, great flexibility can be obtained by using computer generated holography techniques. In this framework, we propose to implement a particular contour extraction primitive, namely the summation of the partial derivatives of an input function, using a direct binary search (DBS) procedure for the design of the spatial filter. This first approach leads, however, to a non-detection of the contours oriented at 45 degrees to the abcissa axis. To solve this problem we propose a modified gradient holographic filter. A theoretical analysis and simulation results are presented.
The manufacture of complex multilayers requires the maker to have a satisfactory monitoring system. The monitoring system can control accuracy not only in optical thicknesses of nonquarterwave layers but can also comp...
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ISBN:
(纸本)081941249X
The manufacture of complex multilayers requires the maker to have a satisfactory monitoring system. The monitoring system can control accuracy not only in optical thicknesses of nonquarterwave layers but can also compensate deposition errors in real-time in order to secure a stable monitoring and eventually to achieve the desired optical performance. In this paper, a computer controlled apparatus for monitoring of wideband optical coatings is described. A method, based on performance measurements during the monitoring of a layer in situ, has been developed to determine the actual refractive index and thickness of the layer in vacuo. The method can be used as a means of detecting deposition errors.
We describe the features of the optical system for Terrestrial Planet Finder, a space-based, cryogenic (35 K) interferometer for direct detection of Earth-type planets around nearby stars. Destructive interference in ...
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ISBN:
(纸本)0819432652
We describe the features of the optical system for Terrestrial Planet Finder, a space-based, cryogenic (35 K) interferometer for direct detection of Earth-type planets around nearby stars. Destructive interference in a stellar interferometer suppresses stellar glare by a factor of several thousand or more, and phase chopping distinguishes planet light from symmetric backgrounds. The mid-infrared (7-20 mu m) is favorable for detecting planetary emission relative to that from the star, and this spectral region also offers important molecular signatures indicative of key atmospheric gases.
In many optical experimental systems, an achromatic 1/4 wavelength retarder is needed to satisfy experiment condition. This can be fulfilled using a rhomb prism which has a nearly constant refractive index in the work...
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ISBN:
(纸本)0819422517
In many optical experimental systems, an achromatic 1/4 wavelength retarder is needed to satisfy experiment condition. This can be fulfilled using a rhomb prism which has a nearly constant refractive index in the working wavelength range. To make the easy use of the prism in the optical system and to avoid the problem of central beam deviation, one type of the prism having three total internal reflection faces can be designed to have the total retarding angle equal to 90 degrees. Though the angle can be relativly easily calculated in principle, the size and optical opening window of the prism depend an the practical and optimum geometric design. In this paper, we will give a few examples of geometric design by taking different size parameters into consideration. We have made the prisms and put them into the application of measuring the magneto-optical Kerr ellipticity with success. Detailed calculation and error reduction in the design are also given.
The opticaldesign and the expected performances of a multi-band imaging system will be presented The instrument is to be operated in a low earth orbit in a pushbroom scanning mode. It has 15 spectral bands with the w...
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ISBN:
(纸本)0819422517
The opticaldesign and the expected performances of a multi-band imaging system will be presented The instrument is to be operated in a low earth orbit in a pushbroom scanning mode. It has 15 spectral bands with the wavelength range extending from 0.45 mu m to 10.7 mu m. The instrument comprises a single mechanically cooled focal plane, a 36 cm aperture, wide field of view off-axis three mirror anastigmatic telescope, and an on-board calibration subsystem. The design has near diffraction limited performance for ail spectral bands from visible to long wavelength infrared (LR). It has high throughput and low polarization sensitivity. To minimize the background noise at long wavelength infrared (LWIR) a cold stop is located at the exit pupil to achieve 100% cold shielding.
We have examined the main constraints on the design of single-channel, high-capacity soliton communication systems. Ln the average soliton regime, the Gordon-Haus timing jitter limits the bit rate to less than 7 Gb/s ...
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ISBN:
(纸本)0819432652
We have examined the main constraints on the design of single-channel, high-capacity soliton communication systems. Ln the average soliton regime, the Gordon-Haus timing jitter limits the bit rate to less than 7 Gb/s for transoceanic fiber links, while for shorter transmission distances the main limitation is fiber perturbations arising from discrete in-line amplification. The use of dispersion-decreasing fibers and of periodic optical, phase conjugation for jitter control can increase significantly the capacity of soliton communication systems. We found that the third-order dispersion assumes a prominent role in this case. Reducing this effect sufficiently, the main constraint becomes the soliton-soliton interactions and bit rates superior to 110 Gb/s can be achieved for amplifier spacings less than 80 km. For higher amplifier spacings the bit rate is limited by the Raman induced timing jitter.
A pupil engineered with a polarization vortex can have a profound impact on certain classes of optical systems. This paper describes the recent history, ongoing activity, and applications of polarization vortices in o...
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ISBN:
(纸本)9780819468154
A pupil engineered with a polarization vortex can have a profound impact on certain classes of optical systems. This paper describes the recent history, ongoing activity, and applications of polarization vortices in optical system design, with special attention to the impact of a vortex filter placed in the pupil of an illumination system. Two systems of particular interest for these types of fields are confocal microscopy, in which a dark field imaging mode is accessible, and immersion lithography, in which azimuthal illumination is favored.
Analysis of aberration performance of two-mirror Cassegrain lens allowed revealing an interesting relationship between them and the central obscuration coefficient epsilon and the distance delta of the focal plane fro...
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ISBN:
(纸本)0819445347
Analysis of aberration performance of two-mirror Cassegrain lens allowed revealing an interesting relationship between them and the central obscuration coefficient epsilon and the distance delta of the focal plane from the vertex of the primary mirror and introducing the coefficient of complexity of Cassegrain lens.
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