Patent ID: 8429974

Claim:
A method for detecting features in a thin-wall structure, the method comprising: generating a plurality of ultrasonic waves within the thin-wall structure; detecting at least one echo from the plurality of ultrasonic waves within the thin-wall structure; and processing the at least one echo to determine a position of at least one feature in the thin-wall structure based on Embedded Ultrasonic Structure Radar (EUSR) beamforming performed in the frequency domain, wherein an A-scan for a particular beamsteering angle associated with the EUSR beamforming is defined as A ⁡ ( φ , t ) = ∑ m = 1 N ⁢ ⁢ ∑ n = 1 N ⁢ ⁢ ifft ⁡ [ X mn ⁡ ( ω ) ⁢ ⅇ - ⅈ ⁢ ⁢ ω ⁡ [ δ m ⁡ ( ω · d ) + δ n ⁡ ( ω · d ) ] ] , where φ is the beamsteering angle, t is time, m is the transmitting sensor, n is the receiving sensor, ω is angular frequency, δ m is the beamforming delay for the transmitting sensor, δn is the beamforming delay for the receiving sensor, and d is a thickness of the thin-wall structure.