Shape from Shading source code

包括以下文章中的代码：（Ccode）1、RuoZhang,Ping-SingTsai,JamesCryerandMubarakShah,ShapefromShading:ASurvey'2、JamesCryer,Ping-SingTsaiandMubarakShah.ShapefromShadingandStereo3、Ping-singTsaiandMubarakShah,ShapeFromShadingUsingLinearApproximation