Patent ID: 8459567

Claim:
A non-linear strain gage comprising: a target for association with an object for which at least one of strain and fatigue damage is to be measured, the target incorporating a nested binary code symbol for perimeter-based deformation and strain analysis, the target emitting a detectable physical quantity and comprising: (a) a rectangular boundary 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 one row of 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 one row of 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; and (b) a core code symbol that provides encoded data; sensor means for pre-processing the detectable physical quantity emitted by the target and outputting data representing the physical quantity, the sensor means being compatible with the detectable physical quantity; analyzing means for analyzing the data output by the sensor means to define the binary code symbol; and measuring means for measuring the strain on the object directly based on the pre-processed and analyzed data.