Frequency selection for compounding synthetic aperture ultrasound images
Bibliographic record
Abstract
In ultrasound imaging range resolution is proportional to the bandwidth of the transmitted pulse; however, noise also increases with frequency and forces a compromise in imaging accuracy. By compounding multiple synthetic aperture ultrasound images from different frequencies, both the resolution and signal-to-noise ratio (SNR) can be improved, unlike when averaging multiple scans at a single frequency, which would only increase SNR. This paper describes a technique for frequency compounding of synthetic aperture ultrasound images and a practical test setup is introduced for frequency selection for imaging systems consisting of a single piezoelectric transducer and a variable-frequency pulser. An example is provided in which point-scatterers in water are scanned along a linear path at frequencies of 16 to 21 MHz. The resulting multi-frequency imaging increases peak SNR by 13% more than single-frequency averaging with the same number of scans and reduces the range-domain support of the point-spread function by 30%.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".