FITS,BMP和SCR图像格式及相互转换

本文介绍了图象的ＦＩＴＳ格式、ＢＭＰ格式和ＳＣＲ格式。ＦＩＴＳ格式已经是天文界的通用格式，几乎所有的天文软件包都支持这一格式，而ＢＭＰ格式在ＰＣ计算机上有广泛的运用，有大量的ＰＣ软件支持ＢＭＰ图象的显示，处理和打印。     

CCD光谱的IRAF和FITS格式转换

美国国立光学天文台的ＩＲＡＦ软件系统，已成为国内光谱处理的主要计算机软件之一。由射电天文需要发展起来的ＦＩＴＳ格式，已作为国际上交换磁带数据资料的通用格式。本文简单地介绍了ＦＩＴＳ格式，讨论了如何将厚片ＣＣＤ光谱观测资料转换为ＩＲＡＦ图像，继而转换为标准ＦＩＴＳ格式，这对于使用ＩＲＡＦ系统进行光谱处理，以及国内国际间的资料交换是有用的。     

1m望远镜计算机网络及软件系统

１ｍ望远镜安装ＰＩＴＥＫ１０２４ＣＣＤ后，前台计算机采用了ＰＣ计算机，后台使用ＳＵＮ工作站，本文介绍了微机和工作站之间的网络连接方式及在网络上使用的软件系统，通过这一网络系统可以使观测数据按ＦＩＴＳ格式方便的转移到ＳＵＮ工作站上，并转储到１５０Ｍ数据流磁带机上。     

1m望远镜计算机网络及软件系统

１ｍ望远镜安装ＰＩＴＥＫ１０２４ＣＣＤ后，前台计算机采用ＰＣ计算机，后台使用ＳＵＮ工作站。本文介绍了微机和工作站之间的网络连接方式及在网络上使用的软件系统。通过这一网络系统可以使观测数据按ＦＩＴＳ格式方便的转移到ＳＵＮ工作站上，并转储到１５０Ｍ数据流磁带机上     

兴隆60 cm望远镜主焦CCD系统测光性能的研究

对兴隆６０ｃｍ望远镜主焦ＣＣＤ系统的测光性能进行了测试和研究．测定了ＣＣＤ快门时间函数,讨论了快门延迟效应对短时间曝光观测的可能影响．通过观测大批Ｌａｎｄｏｌｔ标准星,较准确地定出了ＢＶＲＩ宽带测光的星等系统转换关系,结果表明本系统与标准ＢＶＲＩ系统很接近．对ＣＣＤ系统的天文测光精度作了仔细的检验和分析,并对ＰＳＦ拟合测光和孔径测光两种方法进行了比较     

兴隆60cm望远镜主焦CCD系统测光性能的研究

对兴隆６０ｃｍ望远镜主焦ＣＣＤ系统的测光性能进行了测试和研究,测定了ＣＣＤ快门时间函数,讨论了快门延迟效应对短时间曝光观测的可能影响,通过观测大批Ｌａｎｄｏｌｔ标准星,较准确地定出了ＢＶＲＩ宽带测光的星等系统转换关系,结果表明本系统与标准ＢＶＲＩ系统很接近,对ＣＣＤ系统的天文测光精度作了仔细的检验和分析,工对ＰＳＦ拟合测光和孔径测光两种方法进行了比较。     

具有泊松噪声分布的图象复原方法

本文以ＣＣＤ图象为技术背景，指出ＣＣＤ图象噪声主要将以与信号有关的泊松噪声形式存在。根据图象形成的模型及图象统计特性，提出了最大似然（ＭＩ）法，最大后验概率（ＭＡＰ）法及最大熵（ＭＥ）复原方法。针对ＭＡＰ法提出了具体算法和参数估计方法。并提出应用图象分割法来提高计算机复原速度，节省存储空间。     

未来10年天体测量的发展

首先回顾了依巴谷卫星的观测结果在天文学上的意义,同时指出其不足之处,极限星等仅为 １２ｍａｇ,自行精度不够高等,介绍了正在进行的各种地面上的暗星扩充计划,如ＴＡＣ、ＳＤＳＳ、ＵＣＡＣ－Ｓ,ＰＯＳＳ等,并对它们的预期计划和目前进展情况作了详细描述。叙述了未来１０年可能实施的几个空间天体测量计划,如欧洲空间的ＧＡＩＡ,美国喷气推进实室的ＳＩＭ,德国的ＤＩＶＡ,美国海军天文台的ＦＡＭＥ和俄罗普尔科沃天文     

具有泊松噪声分布的图象复原方法

本文以ＣＣＤ图象为技术背景，指出ＣＣＤ图象噪声主要将以与信号有关的泊松噪声形式存在。根据图象形成的模型及图象统计特性，提出了最大似然法，最大后验概率法及最大复原方法，针对ＭＡＰ法提出了具体算法和参数估计方法，并提出应用图象分割法来提高计算机复原速度，节省存储空间。     

分光仪PSP0的光学设计

本文介绍棱镜分光光度仪ＰＳＰ０的光学设计结果。ＰＳＰ０以ＴＨ７８３２双线ＣＣＤ作为系统探测器，可同时观测０．３６５－１．０微米波长范围内的天体及周转背景的低色散光谱。仪器的入射焦比为Ｆ／１８，平均光谱分辨率约为１０ｎｍ。本文简单介绍了ＰＳＰ０的光学调整，并给出了波长校正实验和配备名古屋大学５０公分望远镜进行试观测的结果。设计和实验结果表明，光学设计很好地满足了天文课题对仪器的设计要求，ＰＳＰ０已可     

A new segmentation algorithm for lunar surface terrain based on CCD images

Terrain classification is one of the critical steps used in lunar geomorphologic analysis and landing site selection. Most of the published works have focused on a Digital Elevation Model(DEM) to distinguish different regions of lunar terrain.This paper presents an algorithm that can be applied to lunar CCD images by blocking and clustering according to image features, which can accurately distinguish between lunar highland and lunar mare. The new algorithm, compared with the traditional algorithm, can improve classification accuracy. The new algorithm incorporates two new features and one Tamura texture feature. The new features are generating an enhanced image histogram and modeling the properties of light reflection, which can represent the geological characteristics based on CCD gray level images. These features are applied to identify texture in order to perform image clustering and segmentation by a weighted Euclidean distance to distinguish between lunar mare and lunar highlands.The new algorithm has been tested on Chang'e-1 CCD data and the testing result has been compared with geological data published by the U.S. Geological Survey. The result has shown that the algorithm can effectively distinguish the lunar mare from highlands in CCD images. The overall accuracy of the proposed algorithm is satisfactory, and the Kappa coefficient is 0.802, which is higher than the result of combining the DEM with CCD images.     

Long Term Variations in Chromospheric Features from Ca-K Images at Kodaikanal

There is a collection of about 100 years of Ca-K line spectroheliograms at the Kodaikanal Observatory (KKL) obtained on daily basis with a single instrument that can be used to study long term variations of various chromospheric features. All the Ca-K images have been digitized using specially developed digitizers with uniform and highly stable light source, high quality lens and 4k×4k format CCD camera. The digitization has been carried out in a room with controlled temperature and humidity. The digitized data are in 16-bit format with pixel resolution of 0.86 arcsec. The digitized images have been calibrated by a process that includes flat-fielding, density to intensity conversion, centering the image, and rotation of the image to make the solar north pole in the fixed direction. Then we applied correction for the limb darkening effect and also made the background in the image uniform. The image background was normalized to unity that enabled us to use the intensity contrast to identify different features, such as plages, enhanced (EN), active (AN), and quite network on images and classified them by using different image contrast and area threshold values. After several experiments with different threshold values for different features and careful analysis of a large number of images, we could fix the threshold values of intensity contrast larger than 1.35 and area larger than 1 arcmin² for plages, larger than 1.35 but area less than 1 arcmin² for EN, and between 1.25?–?1.35 for AN. We compared the quarterly averaged and half yearly averaged plage areas obtained from KKL with the Mount Wilson (MWO) data and sunspot number. We find that the plage area extracted from the KKL is highly correlated with the MWO plage area, though there is a slight difference between the two data set in cycle 19. The plage area of KKL is also highly correlated with the sunspot number. The areas of EN and AN are also found to have smaller quasi-periodic variations apart from the solar cycle variations.     

Example-based super-resolution for single-image analysis from the Chang'e-1 Mission

Due to the low spatial resolution of images taken from the Chang'e-1(CE-1) orbiter, the details of the lunar surface are blurred and lost. Considering the limited spatial resolution of image data obtained by a CCD camera on CE-1, an example-based super-resolution(SR) algorithm is employed to obtain highresolution(HR) images. SR reconstruction is important for the application of image data to increase the resolution of images. In this article, a novel example-based algorithm is proposed to implement SR reconstruction by single-image analysis, and the computational cost is reduced compared to other example-based SR methods. The results show that this method can enhance the resolution of images using SR and recover detailed information about the lunar surface. Thus it can be used for surveying HR terrain and geological features. Moreover, the algorithm is significant for the HR processing of remotely sensed images obtained by other imaging systems.     

同幅双速跟踪成像CCD相机模拟电路系统设计

讨论了同幅双速跟踪成像技术对CCD相机系统的特殊要求,详细地介绍了该相机前端模拟系统的设计思想、系统结构和主要的电路模块。对系统中一些关键电路模块进行了仿真和测试,并对仿真和测试结果进行比较分析,以检验电路系统设计的合理性。     

Precise Determination of the Orientation of the Solar Image

Accurate heliographic coordinates of objects on the Sun have to be known in several fields of solar physics. One of the factors that affect the accuracy of the measurements of the heliographic coordinates is the accuracy of the orientation of a solar image. In this paper the well-known drift method for determining the orientation of the solar image is applied to data taken with a solar telescope equipped with a CCD camera. The factors that influence the accuracy of the method are systematically discussed, and the necessary corrections are determined. These factors are as follows: the trajectory of the center of the solar disk on the CCD with the telescope drive turned off, the astronomical refraction, the change of the declination of the Sun, and the optical distortion of the telescope. The method can be used on any solar telescope that is equipped with a CCD camera and is capable of taking solar full-disk images. As an example to illustrate the method and its application, the orientation of solar images taken with the Gyula heliograph is determined. As a byproduct, a new method to determine the optical distortion of a solar telescope is proposed.     

CCD光谱的IRAF和FITS格式转换

美国国立光学天文台的IRAF软件系统,已成为国内光谱处理的主要计算机软件之一。由射电天文需要发展起来的FITS格式,已作为国际上交换磁带数据资料的通用格式。本文简单地介绍了FITS格式,讨论了如何将厚片CCD光谱观测资料转换为IRAF图像,继而转换为标准FITS格式。这对于使用IRAF系统进行光谱处理,以及国内国际间的资料交换是有用的。     

同幅双速跟踪成像CCD相机数字控制器的设计

在介绍了同幅双速跟踪成像CCD相机的工作原理及其对相机数字控制器的要求之后,阐述了该数字控制器的设计思想,基本结构,并给出了仿真及测试结果。针对仿真及测试过程中出现的问题作了较为详细的分析,并提出了解决的方法。通过软件仿真及硬件测试,表明其设计是基本正确的。     

二维CCD图象数据压缩

本文着重指出了在今后处理大面积CCD图象数据过程中,所将面临的数据存贮困难问题.本文提出了一种有效的不丢失天文信息的压缩CCD图象数据的方法,对银纬b=-60°的一个天区的试验表明,压缩后的图象数据仅为原图象数据的1/30左右,并且可以十分方便地进行图象再现及再处理。在压缩数据过程中,我们在剑桥APM底片扫描机参数化施密特照相底片的基础上,重新安排了CCD图象上天体的对应参数,并视天体的大小及形状,有效地提取保存了天体周围矩阵信息.     

Design and Implementation of CNEOST Image Database Based on NoSQL System

The China Near Earth Object Survey Telescope is the largest Schmidt telescope in China, and it has acquired more than 3 TB astronomical image data since it saw the ?rst light in 2006. After the upgrade of the CCD camera in 2013, over 10 TB data will be obtained every year. The management of the massive images is not only an indispensable part of data processing pipeline but also the basis of data sharing. Based on the analysis of requirement, an image management system is designed and implemented by employing the non-relational database.     

用CCD照相多幅叠加处理检测弱星的试验

本文利用CCD动态范围大且便于数值处理的优点,观测月晕中(强背景上)的弱源。在背景尚未使CCD片子饱和时,即停止露光,存入计算机,多次露光,然后在计算机内多幅叠加,减去背景,显出弱源。通过观测试验和定量估算,结果表明,曝光重叠法,用10幅图叠加时能提高信噪比2.65倍。实测与理想情况符合较好。