發(fā)布時間：2018-03-18 12:17

  本文選題：圖像清晰度　切入點：自動調焦　出處：《光學精密工程》2017年05期 　論文類型：期刊論文

【摘要】：SVOM天文衛(wèi)星附屬的地基廣角相機陣(GWAC)含有36個廣角望遠鏡,其短時標的高精度自動觀測建立在實時自動調焦的基礎上,本文將對廣角望遠鏡實時自動調焦的圖像清晰度評價方法進行研究和實現(xiàn)。文章首先比較研究了常用望遠鏡圖像清晰度評價方法的原理及在GWAC系統(tǒng)上的適用性,得出基于星像能量集中度的兩種方法:星像50%能量半徑、PSF的FWHM值適用于GWAC系統(tǒng)。區(qū)別于常用天文軟件包IRAF費時的算法,本文提出了基于點源強度分布進行PSF擬合計算FWHM的方法,并進一步探究了諸如擬合模型、選星標準、定心精度、擬合半徑、插值方法、插值間隔、FWHM后處理等關鍵方法參數(shù)對FWHM計算精度與速度的影響。最終得到一套適用于GWAC實時自動調焦的清晰度評價方法,并用C++編程實現(xiàn)。本文中方法 FWHM計算誤差為0.046pixel,精度與IRAF相當,計算焦點位置一致;單圖(挑選后約300顆星)計算時間為0.67s,約為IRAF計算時間的1/20,滿足GWAC系統(tǒng)自動調焦的精度與實時性需求。研究結果在GWAC系統(tǒng)中得到應用,并可為其他自動化望遠鏡觀測系統(tǒng)提供參考。
[Abstract]:The ground-based wide-angle camera array attached to SVOM astronomical satellite contains 36 wide-angle telescopes, and its short-time high-precision automatic observation is based on real-time auto-focusing. In this paper, the image sharpness evaluation method of wide-angle telescope real-time auto-focusing is studied and realized. Firstly, the principle of image sharpness evaluation method and its applicability in GWAC system are compared and studied in this paper. Two methods based on star image energy concentration degree are obtained: the FWHM value of star image 50% energy radius is suitable for GWAC system. Different from the time-consuming algorithm of IRAF, a method of calculating FWHM by PSF fitting based on point source intensity distribution is proposed in this paper. And further explored such as fitting model, star selection criteria, centring accuracy, fitting radius, interpolation methods, The influence of key parameters such as interpolation interval and FWHM post-processing on the accuracy and speed of FWHM calculation is obtained. Finally, a set of sharpness evaluation methods suitable for GWAC real-time auto-focusing are obtained. In this paper, the calculation error of FWHM is 0.046 pixel, the accuracy is equal to that of IRAF, and the focal point is the same. The calculation time of single chart (about 300 stars selected) is 0.67 s, about 1 / 20 of the computing time of IRAF, which meets the precision and real-time requirement of GWAC system auto-focusing. The results are applied in GWAC system. It can provide reference for other automatic telescope observation systems.
【作者單位】： 中國科學院國家天文臺空間天文與技術重點實驗室;中國科學院大學;
【基金】：國家自然科學基金資助項目(No.U1331202,No.U1531134) 國家973重點基礎研究發(fā)展計劃資助項目(No.2014CB845800)
【分類號】：TH751;TP391.41

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本文編號：1629540