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Record W1607008155

CODED EXCITATION METHODS FOR ULTRASOUND HARMONIC IMAGING

2007· article· en· W1607008155 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
venuePublished in a venue whose home country is Canada.

Bibliographic record

VenueCanadian acoustics · 2007
Typearticle
Languageen
FieldEngineering
TopicUltrasound and Hyperthermia Applications
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsChirpBandwidth (computing)AcousticsHarmonicWaveformSecond-harmonic imaging microscopyTransducerFrequency domainNonlinear systemHarmonic analysisFourier transformOpticsComputer scienceElectronic engineeringPhysicsRadarEngineeringTelecommunicationsSecond-harmonic generationComputer vision
DOInot available

Abstract

fetched live from OpenAlex

Coded excitation methods offer the potential for improving the SNR without increasing the peak transmitted power and without sacrificing resolution.Our study examines the potential application o f coded waveforms, specifically FM chirps, in harmonic imaging.Such a system, in which nonlinear echoes from tissue are used to form the image, requires the extraction and compression o f the second harmonic portion of the echo signal.Our objective is to obtain the second harmonic using just one transmission, thereby avoiding problems of frame rate reduction and movement artifacts associated with multiple transmission schemes.With the help o f an efficient method for predicting the transient nonlinear field from a focused transducer, design issues such as waveform and bandwidth selection, as well as filters for second harmonic extraction and compression are examined.Simulations reveal the presence of axial sidelobes in the compressed echo waveform as the bandwidth of the transmitted chirp is increased.These sidelobes, resulting from the overlap o f the fundamental and third harmonic bands with the second harmonic, cannot be removed using conventional Fourier filtering.Alternative filtering techniques which utilize the separation o f the harmonic bands o f a backscattered chirp in the joint time-frequency domain are suggested. s o m m a i r eLes mthodes d'excitation code ont le potentiel d 'amliorer le ratio signal-bruit sans augmenter la puissance maximale transmise et sans sacrifier la rsolution.Notre tude examine l'application potentielle de formes d'onde codes, plus spcifiquement de compression d 'impulsions FM pour imagerie harmonique.Dans un tel systme, les chos non-linaires provenant du tissu sont utiliss afin de former l'image, ce qui requiert l 'extraction et la compression de la deuxime portion harmonique du signal d'cho.Notre objectif est d 'obtenir le deuxime harmonique en utilisant seulement une transmission, vitant ainsi des problmes de rduction du temps d 'image et d 'artefacts de mouvement associs avec de multiples schmas de transmission.En utilisant une mthode efficace de prdiction du champs nonlinaire transitoire provenant d'un transducteur focalis, des problmes de conception tels que la slection de forme d 'onde et de la largeur de bande, ainsi que de filtres pour l'extraction et la compression du deuxime harmonique sont examins.Les simulations rvlent la prsence de lobes latraux axiaux dans la forme d'onde compresse au fur et a mesure que la largeur de bande de la compression d 'impulsion transmise est augmente.Ces lobes latraux, dus au chevauchement de la bande harmonique fondamentale et de la troisime bande avec la deuxime bande harmonique ne peuvent pas tre enlevs en utilisant le filtrage conventionnel de Fourier.En tant qu'alternative, des techniques de filtrage utilisant la sparation de bandes harmoniques de compressions d 'impulsions rtrodiffuss dans le domaine commun de temps-frquence sont suggres.

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Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: none
Teacher disagreement score0.897
Threshold uncertainty score0.484

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.014
GPT teacher head0.288
Teacher spread0.274 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it