# US 2024/0393296 A1 · Ultrasound method and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0393296 A1 - Document ID: US20240393296A1 - Status: Published application - Kind: A1 - Application number: 18/693,420 - Filed: 2022-09-28 - Published: 2024-11-28 - Earliest claimed: 2021-09-29 - Assignees: Renishaw PLC - Applicants: Renishaw PLC - Inventors: David John WILSON; Rory Neil HAND; Yining DING - Web page: https://patentgrep.com/patent/US20240393296A1 ## CPC - G01B 17/02: for measuring thickness - G01N 29/32: Arrangements for suppressing undesired influences, e.g. temperature or pressure variations {, compensating for signal noise} - G01N 29/07: by measuring propagation velocity or propagation time of acoustic waves - G01N 29/221: {Arrangements for directing or focusing the acoustical waves (electronic orientation or focusing G01N29/262; sound directing or focusing G10K11/26; mechanical steering of sound transducers or their beams G10K11/35)} - G01N 29/225: {Supports, positioning or alignment in moving situation} - G01N 29/30: Arrangements for calibrating or comparing, e.g. with standard objects - G01N 29/343: {pulse waves, e.g. particular sequence of pulses, bursts} - G01N 2291/011: Velocity or travel time - G01N 2291/02854: Length, thickness - G01N 2291/044: Internal reflections (echoes), e.g. on walls or defects - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A method of determining the time delay between echoes of an ultrasound pulse emitted by an ultrasound inspection device into an object, the method including: with the ultrasound probe in engagement with a front-wall feature of the object such that the ultrasound inspection device's ultrasound axis is arranged at an angle relative to the nominal surface normal of the front-wall feature, taking an ultrasound measurement which includes the ultrasound inspection device emitting an ultrasound pulse and recording echoes thereof; and determining the time delay between echoes of the pulse via a time delay determination process which adjusts the time delay calculation based on the angle of the ultrasound inspection device's ultrasound axis with respect to the nominal surface normal of the front-wall feature. ## Claims ### Claim 1 A method of determining the time delay between echoes of an ultrasound pulse emitted by an ultrasound inspection device into an object, the method comprising: i) with the ultrasound probe in engagement with a front-wall feature of the object such that the ultrasound inspection device's ultrasound axis is arranged at an angle relative to the nominal surface normal of the front-wall feature, taking an ultrasound measurement which comprises the ultrasound inspection device emitting an ultrasound pulse and recording echoes thereof; and ii) determining the time delay between echoes of the pulse via a time delay determination process which adjusts the time delay calculation based on the angle of the ultrasound inspection device's ultrasound axis with respect to the nominal surface normal of the front-wall feature. ### Claim 2 (depends on 1) A method as claimed in claim 1, comprising determining the time delay between an echo from the front-wall feature of the object and an interface echo from the internal or back-wall feature of the object. ### Claim 3 (depends on 1) A method as claimed in claim 1, in which the front-wall feature and the internal or back-wall feature are non-parallel. ### Claim 4 (depends on 1) A method as claimed in claim 1, in which the time delay determination process additionally takes as an input, a variable relating to the nominal thickness of the part at the point of measurement between the front-wall feature and the internal or back-wall feature. ### Claim 5 (depends on 1) A method as claimed in claim 1, in which the time delay determination process additionally takes as an input a variable relating to the nominal speed of sound in the part at the point of measurement. ### Claim 6 (depends on 1) A method as claimed in claim 1, in which the time delay determination process additionally takes as an input an unadjusted measure of the time delay between echoes of the pulse. ### Claim 7 (depends on 1) A method as claimed in claim 1, in which the relative angular orientation of the ultrasound axis and said part at the point the ultrasound measurement is taken, is chosen such that the ultrasound axis of the ultrasound pulse as it propagates through the part is substantially parallel to the nominal surface normal of the internal or back-wall feature at the point of measurement. ### Claim 8 (depends on 1) A method as claimed in claim 1, in which the time delay determination process comprises a compensation model for determining the extent of adjustment based on the angle of the ultrasound inspection device's ultrasound axis with respect to the nominal surface normal of the front-wall feature. ### Claim 9 (depends on 8) A method as claimed in claim 8 in which the compensation model comprises at least one matrix, at least one function, and/or at least one look-up table. ### Claim 10 (depends on 1) A method as claimed in claim 1, comprising determining at least one of the thickness of, material structure of, or speed of sound within the object between the front-wall feature and the internal or back-wall feature, at the point of measurement. ### Claim 11 (depends on 1) A method as claimed in claim 1, in which the ultrasound inspection device comprises a deformable coupling element for engaging the surface of an object to be inspected. ### Claim 12 (depends on 1) A method as claimed in claim 1, in which the ultrasound inspection device is mounted on a positioning apparatus, for example a coordinate positioning apparatus. ### Claim 13 (depends on 12) A method as claimed in claim 12, in which the ultrasound inspection device and object are provided on a positioning apparatus having at least one axis about which the relative orientation of the ultrasound inspection device's ultrasound axis and object can be changed. ### Claim 14 (depends on 12) A method as claimed in claim 12, in which the positioning apparatus facilitates translational motion of the ultrasound probe in at least two linear degrees of freedom, and facilitates rotational motion of the ultrasound probe about at least one axis of rotation. ### Claim 15 (depends on 1) A method as claimed in claim 1, in which the angle of the ultrasound inspection device's ultrasound axis with respect to the nominal surface normal of the front-wall feature is determined from one or more sources independent of the ultrasound signal sensed by the ultrasound inspection device. ### Claim 16 An apparatus comprising a positioning apparatus and an ultrasound inspection device for mounting thereon, configured such that the relative translational position, and the relative angular orientation about at least one axis, of the ultrasound probe and an object to be inspected can be manipulated, and a processing device configured to determine a time delay between echoes of an ultrasound pulse emitted by an ultrasound inspection device into the object, wherein the processing device is configured determine the time delay between echoes of the pulse via a time delay determination process which adjusts the time delay calculation based on the angle of the ultrasound inspection device's ultrasound axis with respect to the nominal surface normal of the front-wall feature.