Hand-Held Measurement Device for Capturing the Visual Impression of A Measurement Object

• US 20140152990A1
• Filed: 10/30/2013
• Published: 06/05/2014
• Est. Priority Date: 11/06/2012
• Status: Active Grant

• Current Assignee: X-Rite Switzerland GmbH (Danaher Corporation)
• Original Assignee: X-Rite Europe GmbH (Veralto Corp.)
• Inventors: Ehbets, Peter, Frick, Beat, Wegmuller, Mark, Hunkemeier, Jorg, Niederer, Guido
• Granted Patent: US 9,772,230 B2
• Time in Patent Office: Days
• US Class Current: 356/405
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/504 Goniometric colour measurements, for example measurements of metallic or flake based paints
• CPC Class Codes: G01N 2021/4735 Solid samples, e.g. paper, glass
• CPC Class Codes: G01N 2021/4783 Examining under varying incidence; Angularly adjustable head
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/57 Measuring gloss
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held

Abstract

A hand-held measurement device for appearance analyses includes a measurement array which comprises a number of illumination means for applying illumination light to a measurement field in at least three illumination directions and a number of pick-up means for capturing the measurement light in at least one observation direction. The illumination directions and the observation directions lie in a common system plane. At least one pick-up means is embodied to spectrally gauge the measurement light in a locally integral way, and at least one imaging pick-up means is embodied to gauge the measurement light in terms of colour in a locally resolved way. The spectral pick-up means and the locally resolving pick-up means are arranged such that they receive the measurement light reflected by the measurement field under the same observation conditions and in particular from the same observation direction.

Claims

1. A hand-held measurement device for capturing the visual impression of a measurement object, comprising a housing (H), wherein said housing (H) accommodates a measurement array (MA) and an electronic controller (C) and comprises a measurement opening (6) through which a measurement field (MF) on a surface of a measurement object (MO) is illuminated and the measurement light reflected by the measurement field (MF) is picked up, wherein the measurement array (MA) comprises a number of illumination means (21-27) for applying illumination light to the measurement field (MF) in at least three illumination directions in relation to a device normal (DN) and a number of pick-up means (31-33) for capturing the measurement light in at least one observation direction in relation to the device normal (DN), wherein at least one spectral pick-up means (32) is embodied to spectrally gauge the measurement light reflected by the measurement field in a locally integral way, and at least one imaging pick-up means (33) is embodied to gauge the measurement light in a locally resolved way, wherein that the imaging pick-up means (33) is also embodied to gauge the measurement light in terms of colour, and in that the spectral pick-up means (32) and the imaging pick-up means (33) are arranged such that they receive the measurement light reflected by the measurement field (MF) under the same observation conditions and in particular from the same observation direction.

2. The hand-held measurement device according to claim 1, wherein the spectral pick-up means (32) comprises a spectrometer (32a) as a light detector and the imaging pick-up means (33) comprises a digital colour camera (33a) as a light detector, and in that the measurement array (MA) comprises a beam splitter (33c) which divides a pick-up beam path (32s, 33s), which in sections is a common beam path, and directs it onto the spectrometer (32a) on the one hand and onto the colour camera (33a) on the other.

3. The hand-held measurement device according to claim 1, wherein the at least three illumination directions and the at least one observation direction lie in a common system plane (SP) which extends through the device normal (DN).

4. The hand-held measurement device according to claim 2, wherein the beam splitter (33c) is arranged such that it is rotated out of the system plane (SP) by essentially 45°

, such that the measurement light for the colour camera (33a) is guided out of the system plane (SP).

5. The hand-held measurement device according to claim 3, wherein the beam splitter (33c) is arranged such that it is rotated out of the system plane (SP) by essentially 45°

, such that the measurement light for the colour camera (33a) is guided out of the system plane (SP).

6. The hand-held measurement device according to claim 1, wherein the observation direction of the spectral pick-up means (32) and the imaging pick-up means (33) is inclined by 15°

with respect to the device normal (DN).

7. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises another spectral pick-up means (31) which receives the measurement light reflected by the measurement field (MF) from a different observation direction to the observation direction of the imaging pick-up means (33).

8. The hand-held measurement device according to claim 7, wherein the observation direction of said other spectral pick-up means (31) is inclined by 45°

with respect to the device normal (DN).

9. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises illumination means (21-24) exhibiting different illumination directions which are inclined with respect to the device normal (DN) in the opposite direction to the observation directions of the pick-up means (31-33).

10. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises illumination means (26, 27) exhibiting different illumination directions which are inclined with respect to the device normal (DN) in the same direction as the observation directions of the pick-up means (31-33).

11. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises an additional gloss illumination means (29) which illuminates the measurement field (MF) with a divergent bundle of beams at an angle of essentially 20°

.

12. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises an optical element (39), in particular a lens with a negative refraction power, which can be moved into and out of the image field and which produces a virtual convex image field curvature (39a).

13. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises an illumination means (28) which illuminates the measurement field (MF) diffusely.

14. The hand-held measurement device according to claim 1, wherein an illumination means (27) is equipped with an optical element (38) which can be introduced into its illumination beam path (27s) and which causes the region illuminated by the illumination means (29) to be reduced in size.

15. The hand-held measurement device according to claim 14, wherein the illumination means (27) equipped with the optical element (38) lies on the same side as the pick-up means (31-33) with respect to the device normal (DN).

16. The hand-held measurement device according to claim 1, wherein the measurement array (MA) comprises an integrated white reference (35) which can be temporarily introduced into the beam paths of the illumination means (21-27) and the pick-up means (31-33).

17. The hand-held measurement device according to claim 16, wherein the white reference (35) is embodied to deflect light hitting it in peripheral regions (35b, 35c) into a central region (35a) of the white reference (35).

18. The hand-held measurement device according to claim 16, wherein the measurement array (MA) comprises a reference illumination means (30) for illuminating the white reference (35) with light exhibiting narrow-band wavelength ranges.

19. The hand-held measurement device according to claim 17, wherein the measurement array (MA) comprises a reference illumination means (30) for illuminating the white reference (35) with light exhibiting narrow-band wavelength ranges.

20. The hand-held measurement device according to claim 1, wherein reference channels are assigned to at least some illumination means (21-27) and decouple a part of the illumination light from the illumination means (21-27) and feed it to a spectrometer (34a) via light conductors (41-47) and a light mixer (34b).

21. The hand-held measurement device according to claim 1, wherein the control array (C) is embodied to correct the colour image data produced by the imaging pick-up means (33), in terms of colour, by means of the spectral measurement values produced by the spectral pick-up means (32) which exhibits the same observation direction as the imaging pick-up means (33).

22. The hand-held measurement device according to claim 1, wherein the control array (C) is embodied to convert the colour image data (601) produced by the imaging pick-up means (33) into standardised colour image data (611) exhibiting a defined resolution on a scale relative to absolute white and in the CIE XYZ or sRGB colour space.

23. The hand-held measurement device according to claim 1, wherein at least some of the illumination means (21-27) are designed in essentially the same way and each comprise at least one primary light source (21a) and a secondary light source (21d) which is formed by an aperture and/or field diaphragm, wherein the at least one primary light source (21a) illuminates the secondary light source (21d) via a collimator (21b) and a homogeniser (21c).

24. The hand-held measurement device according to claim 1, wherein at least some of the illumination means (21-27) comprise a common central light source (50), the output light of which is distributed via a multiplexer (59) onto the illumination channels of the illumination means (21-27) and onto a reference pick-up means (34).

25. The hand-held measurement device according to claim 23, wherein the illumination means (21-27) or the central light source (50) include non-imaging collimators which allow largely loss-free access to the entire etendue of one or more primary light source(s).

26. The hand-held measurement device according to claim 24, wherein the illumination means (21-27) or the central light source (50) include non-imaging collimators which allow largely loss-free access to the entire etendue of one or more primary light source(s).

27. The hand-held measurement device according to claim 25, wherein one or more additional light sources is/are added in the illumination means (21-27) or the central light source (50) via the part of the etendue of one or more primary light source(s) which is not being used.

28. The hand-held measurement device according to claim 26, wherein one or more additional light sources is/are added in the illumination means (21-27) or the central light source (50) via the part of the etendue of one or more primary light source(s) which is not being used.

29. The hand-held measurement device according to claim 24, wherein reference light is decoupled in the illumination means (21-27) or the central light source (50) from the part of the etendue of the primary light source(s) which is not being used.

30. The hand-held measurement device according to claim 25, wherein reference light is decoupled in the illumination means (21-27) or the central light source (50) from the part of the etendue of the primary light source(s) which is not being used.

31. The hand-held measurement device according to claim 26, wherein reference light is decoupled in the illumination means (21-27) or the central light source (50) from the part of the etendue of the primary light source(s) which is not being used.