A new system has been developed for efficient calibration of modern space soft x-ray astronomical telescopes, in particular the x-ray detectors with energy and time resolution. The system provides a large-area (about 1000 cm2 ), highly parallel (±1mrad/24mm), timely and spatially uniform (±5%) beam of x-ray beam. Other special features include a multianode (15 anodes and 17 filters) x-ray source and a narrower pulse (width ≤10 ns) x-ray source. There is a six-axes vacuum turntable that can be used in a wide range with high precision (0.1mm and 0.01°). In this paper, the composition, function and performance of this calibration system will be described in detail.
KEYWORDS: Pulsars, Sensors, X-rays, Signal to noise ratio, X-ray detectors, Monte Carlo methods, Navigation systems, Energy efficiency, Signal detection, Photodetectors
Detection sensitivity is an important indicator of the X-ray pulsar detector. In order to achieve the accuratesensitivity of the detector, a new method of calculate detection sensitivity is proposed calculation. Combining with the characteristics of X-ray pulsar radiation spectrum and detector spectral,classic pulse accumulation model is corrected.A new signal to noise ratio (SNR) calculation formula is deduced by using the new pulse accumulation model.Constructing a new variable Z, which has close relationship with SNR. Through setting the SNR, the analysis and simulation verification for detection sensitivity and confidence level can be made.Simulation verification shows that the monte carlo simulation result is consistent with the theoretical results, and the maximum deviation is only 5%, which is far less than the deviation caused by the space environmentdisturbance.
The paper reviews the relevant development status of domestic and international solar blind ultraviolet and infrared warning, According to current application demands for the payload of the missiles warning in the near-space, this paper presents a dual-band early warning system, which covers the solar blind ultraviolet (250nm-280nm) and MWIR (3000-5000nm). The system uses dual-band to achieve military missile detection and warning, which can effectively reduce the false alarm rate. The optical system uses a four off-axis system as the main anti-optical systems and the splitter was introduced to realize on two spectral bands. According to the detector and the corresponding application needs two-band optical system, this paper completed the calculations and optical system design. After the design is complete, MTF two bands of the optical system in the Nyquist frequency are: solar blind ultraviolet MTF>0.8@39lp/mm, MWIR MTF>0.7@39lp/mm, The maximum RMS spot diameter of two optical systems are smaller than the size of a detector, The single energy cell concentration is greater than 80%.
This paper analyzes the development status of the infrared polarization imaging system. According to the application need of medium wave infrared (MWIR) polarization image, this paper proposes a MWIR polarization coaperture optical system. The system is composed of the front co-aperture optical system and the rear sub-aperture optical system. The rear separate aperture optical system includes four polarization channels. Each channel adopts a 1/4 wave plate and a linear polarizers to obtain three line Stokes polarization components and one circularly Stokes polarization components Thus the system could achieve full polarization imaging. According to the detector and the corresponding application needs, the calculation and optical system design were completed. After the design, the MTF of the optical system is more than 0.3@17lp/mm. The maximum RMS spot diameter is less than the size of detector pixel and a single pixel energy concentration is greater than 80%.
Ultraviolet warning technology is one of the important methods for missile warning. It provides a very effective way to detect the target for missile approaching alarm. With the development of modern technology, especially the development of information technology at high speed, the ultraviolet early warning system plays an increasingly important role. Compared to infrared warning, the ultraviolet warning has high efficiency and low false alarm rate. In the modern warfare, how to detect the threats earlier, prevent and reduce the attack of precision-guided missile has become a new challenge of missile warning technology. Because the ultraviolet warning technology has high environmental adaptability, the low false alarm rate, small volume and other advantages, in the military field applications it has been developed rapidly. For the ultraviolet warning system, the optimal working waveband is 250 nm ~280 nm (Solar Blind UV) due to the strong absorption of ozone layer. According to current application demands for solar blind ultraviolet detection and warning, this paper proposes ultraviolet warning optical system based on interference imaging, which covers solar blind ultraviolet (250nm-280nm) and dual field. This structure includes a primary optical system, an ultraviolet reflector array, an ultraviolet imaging system and an ultraviolet interference imaging system. It makes use of an ultraviolet beam-splitter to achieve the separation of two optical systems. According to the detector and the corresponding application needs of two visual field of the optical system, the calculation and optical system design were completed. After the design, the MTF of the two optical system is more than 0.8@39lp/mm.A single pixel energy concentration is greater than 80%.
In this paper, we introduce a new method for infrared and UV double color warning system. To increase the recognition ability of enemy targets, the warning system should detect the multiple radiation wave band characteristics of the target at the same time. The optical lens are based on lobster-eye optical system, which could get a large field of view through reflecting. The double color detection is based on AlGaN materials and reasonable band design. In the text, we will give the simulation of the lobster-eye lens and optimize the basic structure of the detectors. The main difficulties for the practical use of the system are also introduced.
Semiconductor photon up-converter that can convert infrared to visible light has great application potential in area of new type infrared imaging, photoelectric alarming, and atmospheric monitoring. Based on its working mechanism, this paper introduced the types of up-convert sensor, displayed its advantage when it was applied to infrared imaging. This paper also gave a detailed review about the development of semiconductor photon up-converter recent years. The organic-inorganic hybrid method can suitably combine the superiority of both material systems and complement each other's advantages. Finally, it may promote the development of low-cost,wavelength variable and imaging directly infrared imaging system.
The effective X-ray single photon detector is one of the key technologies for X-ray pulsar detection and navigation. The detector should have good energy and time characteristics and feasibility to meet the needs of X-ray pulsar single photon detection. In this paper, the main kinds of X-ray single photon detectors at present are introduced. By comparing their advantages, disadvantages and usage in satellite, we will give the development trends for the use of X-ray single photon detectors in X-ray pulsar navigation. Finally, we will introduce other new types of X-ray single photon detectors for the future use.
With the development of modern technology, especially the development of information technology at high speed, the ultraviolet early warning system plays an increasingly important role. In the modern warfare, how to detect the threats earlier, prevent and reduce the attack of precision-guided missile has become a new challenge. Because the ultraviolet warning technology has high environmental adaptability, the low false alarm rate, small volume and other advantages, in the military field applications it has been developed rapidly. According to current application demands for solar blind ultraviolet detection and warning, this paper proposes a reconnaissance and early-warning optical system, which covers solar blind ultraviolet (250nm-280nm) and dual field. This structure takes advantage of a narrow field of view and long focal length optical system to achieve the target object detection, uses wide-field and short focal length optical system to achieve early warning of the target object. It makes use of an ultraviolet beam-splitter to achieve the separation of two optical systems. According to the detector and the corresponding application needs of two visual field of the optical system, the calculation and optical system design were completed. After the design, the MTF of the two optical system is more than 0.8@39lp/mm. A single pixel energy concentration is greater than 80%.
The binarized image is very critical to image visual feature extraction, especially shape feature, and the image binarization approaches have been attracted more attentions in the past decades. In this paper, the genetic algorithm is applied to optimizing the binarization threshold of the strip steel defect image. In order to evaluate our genetic algorithm based image binarization approach in terms of quantity, we propose the novel pooling based evaluation metric, motivated by information retrieval community, to avoid the lack of ground-truth binary image. Experimental results show that our genetic algorithm based binarization approach is effective and efficiency in the strip steel defect images and our quantitative evaluation metric on image binarization via pooling is also feasible and practical.
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