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Most of the commenly adotped interpolation algorithems are for the curve machining on CNC machine tools with Cartesian coordinates configuration. For a CNC machine tool with non-Cartesian configuration, new trajectory interpolation algorithem must be developed to machine complex part sueface. Based on the analysis of the geometric characteristics and the CNC grinding principle of indexable inserts, this paper proposes two interpolation algorithems to grind the nose surface of indexable inserts with constant or variable back angle. The algorithm precision analysis is also made in this paper.

Watermarking, as a new technology, has been applied widely in medical images field for its advantages. This paper emphasizes on these works as follows: firstly analyzes the secure requirements of medical images and watermarking functions from the practical applications view, and then reviews some typical algorithms of the existing watermarking and presents a universal evaluating scheme for medical digital images watermarking, finally, some further works are proposed. The purpose for this paper is to study the present watermarking methods and promote the new schemes emergence effectively.

Curve fitting, or interpolation algorithm is core technology for Computer Numerical Control (CNC) systems. A saddle-shaped curve is formed by intersection of two tubes. The trajectory interpolation of saddle-shaped curve is usually carried out through approximating the curve as segments of straight line for automated CNC welding/cutting. This paper proposes a new saddle curve curve fitting algorithm for automated welding/cutting system with non-Cartesian coordinate system. Simulation of the direct curve fitting algorithm has demonstrated that the algorithm has high curve interpolation precision and high feedrate stability.