Fig. 1. Original workpiece

Fig. 2. Point cloud data on the surface of the ear plate

Fig. 3. Processing flow of the enhancement operator

Fig. 4. Specific processing flow of the enhancement operator

Fig. 5. Effect diagram of the enhancement operator. (a) Original image; (b) image obtained after enhancement operator processing

Fig. 6. Experimental results of the algorithm1. (a)‒(d) Sample1‒sample4

Fig. 7. Curvature of different samples. (a)‒(d) Sample1‒sample4

Fig. 8. Experimental results of the algorithm2. (a)‒(d) Sample1‒sample4

Fig. 9. Standard deviation of different samples. (a)‒(d) Sample1‒sample4