Apparatus and method for non-destructive testing using multi-frequency eddy currents

摘要

A method for improving eddy current flaw detection by simultaneously exciting a select plurality of eddy current probe elements with a multiplicity of select frequencies in a simultaneous parallel or serial manner to form a corresponding multiplicity of direct and/or differential images which can be processed together for improved eddy current image resolution. Select eddy current probe elements when driven at select multiple frequencies further provide a capability for simultaneous flaw detection and characterization by dual resolution scanning. Dual flaw resolution is accomplished by first locating a flaw using low resolution frequencies; and thereupon, switching to higher resolution frequencies to characterize the flaw.