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 When an array device such as a CCD, Reticon, etc. is used to observe a star, the gravity center of luminosity of the image of the star can be found as the center of the image by means of the information provided by the luminosity readings of the pixels. The estimation of the accuracy of measuring the position of a stellar image by making 'use of the' gravity center method is expounded in this present article by applying the knowledge of probability and mathematical statistics. And a conclusion is drawn... When an array device such as a CCD, Reticon, etc. is used to observe a star, the gravity center of luminosity of the image of the star can be found as the center of the image by means of the information provided by the luminosity readings of the pixels. The estimation of the accuracy of measuring the position of a stellar image by making 'use of the' gravity center method is expounded in this present article by applying the knowledge of probability and mathematical statistics. And a conclusion is drawn from the exposition that the accuracy of the measurement is inversely proportional to the square root of the overall luminosity readings of the pixels of the stellar image.  当用CCD和Reticon等列阵器件观测恒星时,可利用每个象素的光度读数提供的信息,求出星像的光度重心作为星像的中心。本文应用概率与数理统计知识阐述了重心法测量星像位置时的精度估计,得出测量的精度与星像的象素的总光度读数的平方根成反比的结论。  The effects of the sky background, flat correction and noise on the measurement of the location of a star by means of the gravity center method centering by means of the method of weighten center arc theoretically analysed in this paper. The corresponding error formulas are also presented quantitatively. According to the characteristics of the discreteness of CCD images, the relation between the resolution and the size of a stellar image is derived, thereby proving that the accuracy of the... The effects of the sky background, flat correction and noise on the measurement of the location of a star by means of the gravity center method centering by means of the method of weighten center arc theoretically analysed in this paper. The corresponding error formulas are also presented quantitatively. According to the characteristics of the discreteness of CCD images, the relation between the resolution and the size of a stellar image is derived, thereby proving that the accuracy of the measurement of the stellar image by means of the gravity center method may reach to a few percent of a pixel.The measuring error of the spatial resolution with the No. 1 CCD receiving system of theYunnan Observatory is less than 0.1 arc secnod according to a conversative estimation.  本文从理论上分析了天空背景、平场改正和噪声对重心法测量恒星位置的影响,定量地给出了相应的误差公式。针对CCD图象的离散特点,推出了分辨率和星象大小的关系,从而证明了重心法的测量精度可以达到百分之几象元。对云台一号CCD进行保守估计得到误差小于0.1角秒。  With the developing of the market economy, synthetic evaluation has become an important means for macroscopic management. But there are two difficulties: the first one is that the ordering results calculated by the common method such as the fuzzy distance measure method are in contradiction with the classification results by the fuzzy transformation; the second is how to determine the classification reference marks of evaluation indexes. This paper advanced a mathematics model of synchronizing the classification... With the developing of the market economy, synthetic evaluation has become an important means for macroscopic management. But there are two difficulties: the first one is that the ordering results calculated by the common method such as the fuzzy distance measure method are in contradiction with the classification results by the fuzzy transformation; the second is how to determine the classification reference marks of evaluation indexes. This paper advanced a mathematics model of synchronizing the classification with the ordering to answer the first question. For solving the second problem, “half normal distribution classification method”, “two way normal distribution classification method” and “gravity center method” were proposed. These methods made a foundation of scientific classification.  综合评价是各类宏观管理的重要手段，但是存在两个困难：首先，用通常方法（例如距离测度法）计算的排序结果有时和模糊综合的分级结果相矛盾；其次，如何决定各评价指标的分级参考点。该文提出了一种分级和排序同步的数学模型，用以回答第一个问题。为了解决第二个问题，提出了半正态法，双边正态法和重心法。这些方法构成了科学分级的基础。   << 更多相关文摘 
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