Method for determining a contour data set of spectacle frame rim

1. A method for determining a contour data set of a spectacle frame rim comprising the steps of:

a) providing a plurality (N) of three dimensional measured points along a contour of a spectacle frame rim;

b) calculating a plurality of best torus that fits P points chosen among the N measured points and where P is equal or more than 4;

c) selecting the (T) points among the N measured points that deviate from one of the best torus more than a threshold value; and

d) forming the contour data set with (N-T) three dimensional measured points where the T selected points of step c) are excluded from the list of three dimensional measured points of step a).

2. The method for determining a contour data set of claim 1 , wherein the P points of step b) are consecutive points.

3. The method for determining a contour data set according to claim 1 , wherein the best torus to be calculated in step b) are spheres and P=4.

4. The method for determining a contour data set according to claim 1 , wherein the best torus to be calculated in step b) are non spherical torus and P=6.

5. The method for determining a contour data set according to claim 1 , wherein the P points used to calculate a best torus are different from best torus to best torus.

6. The method for determining a contour data set according to claim 1 , wherein before step c), a substep is implemented to calculate the mean and variance of the radii of the best torus calculated in step b) and the threshold value is said variance.

7. The method for determining a contour data set according to claim 1 , wherein the contour is a circumference of a spectacle frame.

8. The method for determining a contour data set according to claim 1 , wherein the contour is an open path of a spectacle frame.

9. The method for determining a contour data set according to claim 1 , wherein the contour is a U-shaped or V-shaped groove of the spectacle frame.

10. The method for determining a contour data set according to claim 1 , wherein the contour is an edge of the spectacle frame.

11. A method for providing contour data of a spectacle frame rim comprising the steps of:

measuring a plurality (N) of three dimensional points along a contour of a spectacle frame rim;

determining the contour data set according to claim 1 ; and

inputting said contour data set in a computer system.

12. The method for providing a contour according to claim 11 , wherein the method also comprises inputting in the computer system a set of data including wearer's prescription data.

13. A method of calculating an optical system (OS) of an ophthalmic lens according to a given spectacle frame comprising the steps of:

providing the contour data set of the spectacle frame according to claim 1 ,

providing wearer's data, and

optimization of the optical system (OS) according to at least the criteria consisting of said contour data set of the spectacle frame, the wearer's data and at least one positioning data, so as to generate at least two optical surfaces (S 1 , S 2 ).

14. A computer program product comprising one or more stored sequence of instruction that is accessible to a processor and which, when executed by the processor, causes the processor to carry out at least one step of claim 1 .

15. A non-transitory computer readable medium carrying one or more sequences of instructions of the computer program product of claim 14 .