1. An image processing method for feature retention associated with averaging a plurality of image data, said image processing method comprising: scaling and aligning a plurality of image data for acquiring feature information; determining a plurality of two-dimensional feature label points according to said feature information for generating at least one Bezier curve; utilizing said at least one Bezier curve to generate at least one Bezier tube and performing Bezier tube fitting for generating result of Bezier tube fitting; deforming, by a processor, said plurality of image data according to said Bezier tube or said result of Bezier tube fitting for generating a plurality of deformed image data, wherein said deforming process comprises (a). averaging said at least one set Bezier tube control points across said plurality of image data for generating a plurality of averaged Bezier tube control points, (b). determining a transformation of individual Bezier tube control points of said plurality of image data relative to their corresponding averaged Bezier tube control points, for generating a transformation information of each of said plurality of image data, (c). deforming said plurality of image data according to said transformation information for each of said plurality of image data and a correspondence map of each of said plurality of image data, wherein said correspondence map of each of said plurality of image data is generated by disposing said averaged Bezier tube control points on one of said plurality of image data being scaled and aligned; and averaging said plurality of deformed image data for generating feature-retained averaged image data.