High density, rectangular binary code symbol

1. 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 rectangular binary code symbol including:

a solid, continuous outer perimeter;

first and second data regions along adjacent sides of the perimeter, each data region comprising at least two rows, each row comprising a plurality of data cells, each data cell representing a single bit of binary data;

first and second utility regions along adjacent sides of the perimeter opposite the first and second data regions, each utility region comprising at least two rows, each row comprising a plurality of utility cells of alternating appearance;

first and second finder cells at opposite corners of the rectangle; and

inner and outer quiet regions distinguishing the first and second data regions, the first and second utility regions, and the first and second finder cells from their background;

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.

2. The non-linear strain gage of claim 1 , further comprising means for utilizing the strain measurement to provide information on at least one of fatigue damage and strain hysteresis for materials of known and unknown mechanical properties.

3. The non-linear strain gage of claim 1 , further comprising means for utilizing the strain measurement to assist in component lifecycle management.

4. The non-linear strain gage of claim 1 , further comprising means for utilizing the strain measurement based on collected damage accumulation data.

5. The non-linear strain gage of claim 1 , wherein the binary code symbol is defined a priori by manufacture.

6. The non-linear strain gage of claim 1 , wherein the target is identified in a pre-existing pattern that defines the binary code symbol.

7. A method of measuring strain on an object directly, using a binary code symbol for non-linear strain measurement that includes:

a solid, continuous outer perimeter;

first and second data regions along adjacent sides of the perimeter, each data region comprising at least two rows, each row comprising a plurality of data cells, each data cell representing a single bit of binary data;

first and second utility regions along adjacent sides of the perimeter opposite the first and second data regions, each utility region comprising at least two rows, each row comprising a plurality of utility cells of alternating appearance;

first and second finder cells at opposite corners of the rectangle; and

inner and outer quiet regions distinguishing the first and second data regions, the first and second utility regions, and the first and second finder cells from their background,

the method comprising the steps of:

associating the binary code symbol 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.

8. The method of claim 7 , wherein the binary code symbol is defined a priori by manufacture and the associating step comprises applying the binary code symbol to the object.

9. The method of claim 7 , wherein the associating step comprises identifying the binary code symbol a priori.

10. The method of claim 7 , further comprising the step of utilizing the strain measurement to provide information on at least one of fatigue damage and strain hysteresis for materials of known and unknown mechanical properties.

11. The method of claim 7 , further comprising the step of utilizing the strain measurement to assist in component lifecycle management.

12. The method of claim 7 , further comprising the step of utilizing the strain measurement based on collected damage accumulation data.