Improving Precision of Autocollimation with Cubic Spline Interpolation Functions
利用三次样条插值提高自准直仪的准确度

Because of the CCD pixel size,the precision of autocollimation is above arcsec level which is far from high level meterage.Cubic Spline Interpolation Functions was used to subdividing CCD pixel,then beeline edge fitting was used to detecting the edge of image to improve the precision of autocollimation.Unaided measurement was used in the experiment,angles from turning autocollimation and calculating was compared,then the precision of arithmetic was analyzed.The precision of autocollimation was obviously improved by using the arithmetic,0.1 arc second precision was achieved in the result.