OPTICAL MEASUREMENT DEVICE

• US 20090174878A1
• Filed: 04/10/2007
• Published: 07/09/2009
• Est. Priority Date: 04/18/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Wadman, Sipke
• Granted Patent: US 7,872,754 B2
• Time in Patent Office: Days
• US Class Current: 356/39
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/442 Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

An optical measurement device for measuring an optical appearance of a surface of a sample, in particular the surface of a human skin, wherein the optical measurement device comprises: a first illumination device (16) for illuminating the surface (14) with a first illumination beam (22), wherein the first illumination beam (22) is incident at a first angle of incidence (38) onto the surface (14); and a detection device (28) for detecting a response beam (22), wherein the response beam (42) is a response of the sample (12) to the first illumination beam (22), comprising at least one screen (27) for intercepting the response beam (42) and at least an image detection component (29). The optical measurement device (10) comprises a second illumination device (18), wherein the second illumination device (18) is providing a second illumination beam (24) with a second angle of incidence (54) at the surface (14), wherein the first angle of incidence (38) is different from the second angle of incidence (54).

Claims

1. An optical measurement device for measuring an optical appearance of a surface of a sample (12), in particular the surface (14) of a human skin, wherein the optical measurement device comprises:

a first illumination device (16) for illuminating the surface (14) with a first illumination beam (22), wherein the first illumination beam (22) is incident at a first angle of incidence (38) onto the surface (14); and

a detection device (28) for detecting a response beam (42), wherein the response beam (42) is a response of the sample (12) to the first illumination beam (22), comprising at least one screen (27) for intercepting the response beam (42) and at least an image detection component (29), characterized in that the optical measurement device (10) comprises a second illumination device (18), wherein the second illumination device (18) is providing a second illumination beam (24) with a second angle of incidence (54) at the surface (14), wherein the first angle of incidence (38) is different from the second angle of incidence (54).

2. The optical measurement device of claim 1, characterized in that at least the optical measurement device (10) comprises at least a third illumination device (20), providing a third illumination beam (26) with a third angle of incidence (66) at the surface (12), wherein the third angle of incidence (66) is different from the first (38) and/or the second angle of incidence (54).

3. The optical measurement device of claim 1, characterized in that the image detection component (29) is a camera (30), in particular a digital camera.

4. The optical measurement device of claim 1, characterized in that the screen (27) is a full hemispherical screen, intercepting the response beam (42) in about 360°

above the surface of the sample (12).

5. The optical measurement device of claim 1, characterized in that the screen (27) is a substantially flat screen, covering approximately a quarter hemisphere.

6. The optical measurement device of claim 1, characterized in that the optical measurement device (10) comprises a base plate (84), having a measuring port (86) through which the illumination beam (22, 24, 26) is propagating in order to illuminate the surface (14) and the response beam (42) is propagating towards the detection device (28).

7. The optical measurement device of claim 6, characterized in that the measuring port (86) is designed such that a small area of the surface (14) of the sample (12) is covered, in order to achieve a good spatial resolution.

8. The optical measurement device of claim 6, characterized in that the measuring port (86) has the shape of an elongated aperture in order to detect the response beam (42) that is the response of the sample (12) to the illumination beam (22, 24, 26), scattered at a sub-surface area, wherein the response beam (42) is generated in a distance from the location of the illumination beam (22, 24, 26) incident on the surface (12).

9. The optical measurement device of claim 8, characterized in that the illumination beam directly reflected at the surface (14) is cut off by means of a substantially vertical baffle (73) arranged in the elongated aperture.

10. The optical measurement device of claim 8, characterized in that the elongated aperture is designed such that the response beam shows a spatial distribution related to a depth at which the illumination beam (22, 24, 26) was scattered in the sub-surface area (40).

11. The optical measurement device of claim 1, characterized in that the optical measurement device (10) comprises components (32) for shielding the response beam (42) from the illumination beam (22, 24, 26).

12. The optical measurement device of claim 1, characterized in that the optical measurement device (10) comprises at least one mirror (32) for imaging the response beam (42) intercepted by the screen (27) into the image detection component (28).

13. The optical measurement device of claim 2, characterized in that each of the first (16) and/or the second (18) and/or the third illumination device (20) comprises a first and/or a second and/or a third radiation source and/or a first and/or a second and/or a third fiber for directing the first (22) and/or second (24) and/or third illumination beam (26) onto the surface (14) of the sample (12).

14. The optical measurement device of claim 13, characterized in that the optical measurement device (10) comprises one radiation source and a first, a second and a third fiber, wherein the first fiber realizes the first angle of incidence (38), the second fiber realizes the second angle of incidence (54) and the third fiber realizes the third angle of incidence (66) of the respective illumination beam (22, 24, 26).

15. The optical measurement device of claim 13, characterized in that the first fiber and/or the second fiber and/or the third fiber is arrangeable in a close distance to the surface (14) in order to realize a small illumination spot (39) at the surface (14).

16. The optical measurement device of claim 1, characterized in that the detection device (28) comprises at least one color filter.

17. The optical measurement device of claim 1, characterized in that the optical measuring device comprises at least one polarisation filter (34, 36).

18. The optical measurement device of claim 1, characterized in that the optical measurement device (10) comprises a calculation device for determining a correlation factor out of the detected response beam.

21. The method of claims 9, characterized by using a data base in order to perform an assignment of the respective correlation factors to the respective features of the sample (12).

19. A method for inspecting a surface of a sample and measuring an optical appearance of the sample (12), in particular the surface (14) of a human skin, comprising the following steps:

illuminating the surface (14) of the sample (12) with a first illumination beam (22) incident at a first angle of incidence (38) at the surface (14);

intercepting a response beams (42), wherein the response beam (42) is a response of the sample (12) to at least the first illumination beam (22);

characterized by illuminating the surface (14) with a second illumination beam (24) incident at a second angle of incidence (54) at the surface (14); and

estimating a first and/or at least a second correlation factor from the intercepted response beam (42);

assigning the first and/or the at least second correlation factor to a first and/or a second feature of the optical appearance of the sample (12).

20. The method of claim 19, characterized by a second step of illuminating the surface (14) with at least a third illumination beam (26) and estimating at least a third correlation factor in order to obtain at least a third feature of the optical appearance of the sample (12).