Phased Array Ultrasonic Calibration Using Normalization Curves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing phased array ultrasound (PAUT) inspection methods for metal tubes face challenges in achieving reliable calibration for defects at intermediate angles due to non-linearity, requiring numerous calibration notches and being susceptible to amplitude variations from single notches, leading to 'gaps' in calibration reliability.
Innovation Solution
A gapless calibration method using a small number of calibration notches with a one-time acoustic normalization procedure, involving angle response curve measurements and Lorentzian curve fitting to generate a normalization curve for interpolating between notch angles, ensuring consistent echo response amplitudes across a continuous range of angles and positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of calibration notches are used to minimize angular calibration gaps, then calibration reliability is improved, but machining cost and time consumption increase
Solution Approach 1:
The patent performs preliminary acoustic normalization using a small number of calibration notches (e.g., 3 notches at 0°, ±15°) to establish baseline response characteristics. This preliminary calibration data is then used to generate lookup tables and interpolation algorithms that enable gapless calibration for intermediate angles without requiring physical notches at every angle, thus resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent creates virtual calibration data for intermediate angles by interpolating from a small set of actual calibration notches. The system generates lookup tables containing pre-calculated gain compensation values for all intermediate angles based on the limited physical notches, effectively copying and extending the calibration information without requiring corresponding physical notches for every angle
2Device complexity
If a single calibration notch is used for calibration, then the calibration process is simplified, but the method becomes susceptible to amplitude variations from that single notch
Solution Approach 1:
The patent combines data from multiple calibration notches (e.g., 0°, +15°, -15°) to establish a comprehensive acoustic normalization profile. By merging the response characteristics from multiple notches at different angles, the system creates a more robust baseline that averages out anomalies from any single notch, improving reliability while maintaining manageable process complexity
Solution Approach 2:
The patent uses the combined calibration data from multiple notches to generate lookup tables that contain pre-calculated compensation values for all intermediate angles. This copying approach allows the system to leverage information from multiple physical notches to provide reliable calibration across the entire angular range without requiring physical notches at every angle
3Measurement precision
If calibration is performed for each notch angle using perpendicular reception, then accurate calibration is achieved for specific angles, but intermediate angles cannot be reliably calibrated due to system non-linearity
Solution Approach 1:
The patent introduces interpolation algorithms and lookup tables as intermediaries between the discrete calibration notches and the continuous angular range. These intermediaries take the precise calibration data from notches at specific angles and generate compensated gain values for intermediate angles through mathematical interpolation, enabling reliable calibration across the full angular range without requiring physical notches at every angle
Solution Approach 2:
The patent changes the calibration approach from direct perpendicular reception (which only works at specific discrete angles) to a parameter-based compensation method. By measuring the angular response of calibration notches and using this data to calculate gain compensation factors for all intermediate angles, the system transforms the calibration process from angle-specific to continuously adaptable across the full angular range
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides reliable, gapless calibration with minimal notch variations, enabling consistent defect detection across a wide angular range using a reduced number of calibration notches, improving productivity and reducing machining costs.
Implementation Method 1
the echo response amplitude is calibrated for each notch on the calibration tube by receiving the scattered ultrasound energy
Data Source
AI summary
Disclosed is a calibration system and method for a phased array ultrasound pipe inspection system, in which reliable calibration is obtained for notches at all angles using only a small number of notches for the calibration. The method comprises a one-time normalization step and a system calibration step which may be performed at regular intervals. Ultrasound transmission is in a single diverging beam for each aperture, while reception is selective for multiple well-defined reception angles. During the normalization step, plots of maximum response vs reception angle are plotted for each notch, and a normalization curve is constructed by fitting the maxima of these plots. The normalization curve is used to derive calibration targets at specific reception angles for specific calibration notches, which are then used for the system calibrations.