Apparatus and method for characterizing a replica tape

• US 9,207,174 B2
• Filed: 02/20/2015
• Issued: 12/08/2015
• Est. Priority Date: 01/09/2013
• Status: Active Grant

• Current Assignee: DeFelsko Corporation
• Original Assignee: DeFelsko Corporation
• Inventors: Vandervalk, Leon, Stachnik, Robert V., Davis, James Edward
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): RAHMAN, MD M
• Application Number:
  US14/627,611
• Publication Number:
  US 20150233826A1
• Time in Patent Office: 291 Days
• Field of Search: 356/72
• US Class Current: 1/1
• CPC Class Codes: G01B 11/06 for measuring thickness ; e.g. of sheet material thickness measurement by thermal means G01B21/085
• CPC Class Codes: G01B 7/10 using magnetic means, e.g. by measuring change of reluctance
• CPC Class Codes: G01B 7/14 for measuring distance or clearance between spaced objects or spaced apertures G01B7/30 takes precedence
• CPC Class Codes: G01N 21/59 Transmissivity G01N21/25 takes precedence
• CPC Class Codes: G01N 2201/062 LED's
• CPC Class Codes: G01N 2201/12 Circuits of general importance; Signal processing

Abstract

An apparatus and method are provided for characterizing a replica tape which has been embossed, compressed or cast on a surface of a material to be measured to replicate that surface. The replica tape is secured between first and second holding components such that a compressible surface of the replica tape is secured against the first holding component. A light source transmits light through the second holding component, the replica tape and the first holding component. An image sensor measures intensity of the light respectively transmitted through at least two measurement points of the compressible surface of the replica tape. A processing unit converts the measured light intensity transmitted through the at least two measurement points into at least two data values each respectively relating to a measurement statistic of the replica tape at a corresponding one of the at least two measurement points, respectively.

Claims

1. An apparatus for characterizing a replica tape which has been embossed, compressed or cast on a surface of a material, the replica tape including a first surface and an opposing second surface replicating the surface of the material on which the replica tape was embossed, compressed or cast, the second surface of the replica tape having a plurality of measurement points extending along a first direction substantially perpendicular to a thickness of the replica tape extending in a second direction between the first and second surfaces of the replica tape, wherein the apparatus comprises:

a mobile processing device including a camera and a processing unit; and

a holding component having opposing first and second surfaces in the second direction, the first surface of the holding component being configured to be arranged proximate to the camera of the mobile processing device, and the second surface of the holding component being configured to secure the first surface of the replica tape to the holding component,

wherein the camera of the mobile processing device is configured to measure an intensity of light transmitted in the second direction through at least two of the plurality of measurement points of the second surface of the replica tape, respectively, and

wherein the processing unit of the mobile processing device is configured to receive the measured intensity of the light transmitted through the at least two of the plurality measurement points and convert the measured light intensity at the at least two measurement points into at least two data values each respectively relating to a measurement statistic of the replica tape at a corresponding one of the at least two measurement points, respectively.

2. The apparatus according to claim 1, wherein the light is transmitted to the second surface of the replica tape from at least one of an ambient light and an external light source.

3. The apparatus according to claim 1, wherein the processing unit is configured to determine a peak to valley thickness of the at least two measurement points based on a measured thickness of the replica tape.

4. The apparatus according to claim 1, wherein the processing unit is configured to record in a memory unit the received measured light intensity at the at least two measurement points, and convert the measured light intensity at the at least two measurement points by substituting the recorded measured light intensity with thickness values recorded in a look-up table in association with corresponding values of the measured light intensity, respectively.

5. The apparatus according to claim 4, comprising:

an input unit configured to receive an operator input to update the thickness values recorded in the look-up table.

6. The apparatus according to claim 4, comprising:

a display unit configured to display at least one of;

(i) a two-dimensional rendering of the thickness values corresponding to the measured light intensity at the at least two measurement points, and (ii) a two-dimensional rendering of a three-dimensional surface of the replica tape based on the thickness values corresponding to the measured light intensity at the at least two measurement points.

7. The apparatus according to claim 6, wherein the processing unit is configured to generate an image in which a portion of the replica tape having the maximum thickness of the replica tape is correlated with a darkest area of the image to correct for variations between samples of the replica tape.

8. The apparatus according to claim 4, wherein the look-up table is based on measured thickness values of the replica tape in association with corresponding measured light intensities that are stored after calibration with measured thickness values of an uncompressed, unembossed or uncast replica tape in association with corresponding measured light intensities of the uncompressed, unembossed or uncast replica tape.

9. The apparatus according to claim 4, wherein the look-up table is based on measured thickness values recorded without being associated with measured light intensities of measurement points of the replica tape to account for at least one of (i) variations in measurements, (ii) changes to mechanical components of the apparatus, and (iii) buildup of debris in the apparatus.

10. The apparatus according to claim 1, wherein the processing unit is configured to record in a memory unit the received measured light intensity at the at least two measurement points, and convert the measured light intensity at the at least two measurement points by applying an algorithm to the recorded measured light intensity to obtain corresponding thickness values for the measured light intensity at the at least two measurement points, respectively.

11. The apparatus according to claim 10, comprising:

an input unit configured to receive an operator input to update the thickness values recorded in the look-up table.

12. The apparatus according to claim 10, comprising:

a display unit configured to display at least one of;

(i) a two-dimensional rendering of the thickness values corresponding to the measured light intensity at the at least two measurement points, and (ii) a two-dimensional rendering of a three-dimensional surface of the replica tape based on the thickness values corresponding to the measured light intensity at the at least two measurement points.

13. The apparatus according to claim 12, wherein the processing unit is configured to generate an image in which a portion of the replica tape having the maximum thickness of the replica tape is correlated with a darkest area of the image to correct for variations between samples of the replica tape.

14. The apparatus according to claim 10, wherein the algorithm is based on measured thickness values of the replica tape in association with corresponding measured light intensities that are recorded after calibration with measured thickness values of an uncompressed, unembossed or uncast replica tape in association with corresponding measured light intensities of the uncompressed, unembossed or uncast replica tape.

15. The apparatus according to claim 10, wherein the algorithm is based on measured thickness values recorded without being associated with measured light intensities of measurement points of the replica tape to account for at least one of (i) variations in measurements, (ii) changes to mechanical components of the apparatus, and (iii) buildup of debris in the apparatus.

16. The apparatus according to claim 1, wherein the processing unit is configured to determine at least one marking in the replica tape to distinguish between different grades of the replica tape, and adjust corresponding thickness values associated with the measured light intensities at the at least two measurement points based on a particular grade of the replica tape.

17. The apparatus according to claim 1, wherein the holding component includes a through-hole arranged between the first and second surfaces of the holding component to permit light transmitted through the replica tape to be received at the camera.

18. The apparatus according to claim 1, wherein the holding component is translucent between the first and second surfaces of the holding component arranged between the camera and the replica tape.

19. The apparatus according to claim 1, wherein the holding component includes a securing mechanism configured to secure the first surface of the replica tape to the second surface of the holding component.

20. A method for characterizing a replica tape, the method comprising:

embossing, compressing or casting the replica tape on a surface of a material to be measured, the embossed, compressed or cast replica tape having a first surface and an opposing second surface which is compressible to replicate the surface of the material, the second surface having a plurality of measurement points;

securing the replica tape to a holding component having a first surface and an opposing second surface such that the first surface of the replica tape is secured to the second surface of the holding component to expose the second surface of the replica tape to light;

arranging the first surface of the holding component proximate to a camera of a mobile processing device;

measuring, in the camera of the mobile processing device, an intensity of light respectively transmitted through at least two of the measurement points of the second surface of the replica tape; and

converting, in a processing unit of the mobile processing device, the measured light intensity transmitted through the at least two measurement points into at least two data values each respectively relating to a measurement statistic of the replica tape at a corresponding one of the at least two measurement points, respectively.

21. The method according to claim 20, wherein the light is transmitted to the second surface of the replica tape from at least one of an ambient light and an external light source.

22. The method according to claim 20, comprising:

measuring a thickness of the replica tape prior to the embossing, compressing or casting of the replica tape on the surface of a material.

23. The method according to claim 22, comprising:

determining, in the processing unit of the mobile processing device, a peak to valley thickness of the at least two measurement points based on the measured thickness of the replica tape.

24. The method according to claim 22, comprising:

generating and displaying a two-dimensional representation of the converted data values,

wherein the generated and displayed two-dimensional representation of the converted data values includes at least one of;

(i) a two-dimensional rendering of thickness values of the replica tape corresponding to the measured light intensity at the at least two measurement points, and (ii) a two-dimensional rendering of a three-dimensional surface of the replica tape based on the thickness values corresponding to the measured light intensity at the at least two measurement points.

25. The method according to claim 24, wherein the generating and displaying of the two-dimensional representation of the converted data values includes generating an image in which a portion of the replica tape having the maximum thickness of the replica tape is correlated with a darkest area of the image to correct for variations between samples of the replica tape.

26. The method according to claim 20, wherein the converting of the measured light intensity comprises:

recording in a memory unit the received measured light intensity at the at least two measurement points; and

converting the measured light intensity at the at least two measurement points by substituting the recorded measured light intensity with thickness values recorded in a look-up table in association with corresponding values of the measured light intensity, respectively.

27. The method according to claim 26, wherein the look-up table is based on measured thickness values of the replica tape in association with corresponding measured light intensities that are stored after calibration with measured thickness values of an uncompressed, unembossed or uncast replica tape in association with corresponding measured light intensities of the uncompressed, unembossed or uncast replica tape.

28. The method according to claim 20, wherein the converting of the measured light intensity comprises:

recording in a memory unit the received measured light intensity at the at least two measurement points; and

converting the measured light intensity at the at least two measurement points by applying an algorithm to the recorded measured light intensity to obtain corresponding thickness values for the measured light intensity at the at least two measurement points, respectively.

29. The method according to claim 28, wherein the algorithm is based on measured thickness values of the replica tape in association with corresponding measured light intensities that are recorded after calibration with measured thickness values of an uncompressed, unembossed or uncast replica tape in association with corresponding measured light intensities of the uncompressed, unembossed or uncast replica tape.