Multi-format,binary code symbol for non-linear strain measurement

• US 20090312961A1
• Filed: 08/17/2007
• Published: 12/17/2009
• Est. Priority Date: 08/17/2006
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: Direct Measurements, Inc.
• Inventors: Ranson, William, Vachon, Reginald, Hovis, Gregory
• Granted Patent: US 8,347,727 B2
• Time in Patent Office: Days
• US Class Current: 702/42
• CPC Class Codes: G01B 11/165 by means of a grating deformed by the object
• CPC Class Codes: G01L 1/24 by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
• CPC Class Codes: G06K 19/06037 multi-dimensional coding

Abstract

A binary code symbol for non-linear strain measurement that can be constructed in any geometric shape having a solid, continuous perimeter containing straight line segments. The symbol includes finder cells to “orient” the symbol in order to associate strain measurements with physical dimensions; and contains encoded data in “data regions” and/or “utility regions.” The data and utility regions can be distinct and separate, combined, exclusive (i.e. data regions and no utility regions, or utility regions and no data regions), or omitted. The data “density” can be varied depending upon the application, by varying the number of distinct data or utility cells present in the data regions or utility regions.

Claims

1. A binary code symbol for perimeter-based, non-linear strain measurement using discrete or analog deformation analysis methods, comprising:

an outer perimeter constructed of line segments,

orienting means for determining the orientation of the binary code symbol, in order to associate strain measurements with physical dimensions, wherein the orienting means is bounded at least in part by the outer perimeter, and

inner and outer quiet regions for distinguishing the orienting means from its background.

2. The binary code symbol of claim 1, wherein the orienting means comprises at least one distinct feature.

3. The binary code symbol of claim 2, wherein the at least one distinct feature is a finder cell.

4. The binary code symbol of claim 1, wherein the orienting means comprises at least two distinct features to provide redundancy and to enable robust algorithms to determine symbol orientation.

5. The binary code symbol of claim 1, further comprising an inner perimeter constructed of line segments.

6. The binary code symbol of claim 5, wherein the inner perimeter is an enlargement of the outer perimeter having a fractional scale factor greater than 0 and less than 1.

7. The binary code symbol of claim 5, wherein the inner and outer perimeters are concentric.

8. The binary code symbol of claim 5, wherein the inner and outer perimeters have different shapes.

9. The binary code symbol of claim 1, wherein the outer perimeter is a polygon.

10. The binary code symbol of claim 1, further comprising at least one data region containing encoded data region data, wherein the at least one data region is bounded at least in part by the outer perimeter, and wherein the inner and outer quiet regions further distinguish the at least one data region from its background.

11. The binary code symbol of claim 10, further comprising an inner perimeter constructed of line segments, wherein the at least one data region is bounded at least in part by the inner perimeter.

12. The binary code symbol of claim 10, wherein the at least one data region comprises a plurality of data cells, and the encoded data region data is encoded in the data cells.

13. The binary code symbol of claim 12, wherein the density of the data region data is determined by one of the number and width of the data cells.

14. The binary code symbol of claim 12, wherein the at least one data region contains multiple rows of data cells.

15. The binary code symbol of claim 10, further comprising at least one utility region containing encoded utility data, wherein the at least one utility region is bounded at least in part by the outer perimeter, and wherein the inner and outer quiet regions further distinguish the at least one utility region from its background.

16. The binary code symbol of claim 15, further comprising an inner perimeter constructed of line segments, wherein the at least one utility region is bounded at least in part by the inner perimeter.

17. The binary code symbol of claim 15, wherein the at least one utility region comprise a plurality of utility cells with alternating appearance, and the utility data is encoded in the utility cells.

18. The binary code symbol of claim 17, wherein the density of the utility data is determined by one of the number and width of utility cells.

19. The binary code symbol of claim 15, wherein the at least one utility region contains multiple rows of utility cells.

20. The binary code symbol of claim 19, wherein the multiple rows of encoded utility data store at least one of auxiliary information and codes.

21. The binary code symbol of claim 15, wherein the at least one data region and the at least one utility region are distinct and separate.

22. The binary code symbol of claim 15, wherein the at least one data region and the at least one utility region are combined.

23. The binary code symbol of claim 22, wherein the combined data and utility regions encode one of all data region data, all utility data, and a combination of data region data and utility data.

24. A non-linear strain gage comprising:

a target associated with an object for which at least one of strain and fatigue damage is to be measured and emitting a detectable physical quantity, the target comprising a binary code symbol in accordance with claim 1,

sensor means for pre-processing the detectable physical quantity emitted by the target and output data representing the physical quantity, the sensor means being compatible with the detectable physical quantity;

means for analyzing the data output by the sensor means to define the binary code symbol; and

means for measuring the strain on the object directly based on the pre-processed and analyzed data.

25. A method of measuring strain on an object directly, comprising the steps of:

associating a binary code symbol in accordance with claim 1 with an object in such a way that deformation of the binary code symbol and deformation under load of the object bear a one-to-one relationship, wherein the binary code symbol emits a detectable physical quantity;

identifying the changes in the binary code symbol as a function of time and change in the load applied to the object; and

translating the changes in the binary code symbol into a direct measurement of strain.