Elevational diffraction effect in estimating the local attenuation-coefficient slope using synthetic-transmit-aperture ultrasound imaging
Bibliographic record
Abstract
Accurate estimation of attenuation coefficient slope (ACS) enhances quantitative ultrasound imaging. We investigate diffraction bias in reference-phantom-free ACS estimation for synthetic transmit aperture (STA) imaging with a one-dimensional linear array. Simulations and experiments show that the elevational focus, rather than the lateral focus, introduces depth-dependent bias: ACS underestimation before focus and overestimation beyond. Applying a Gaussian diffraction correction reduced the ACS error from ±0.28 to ±0.06 dB/cm-MHz in simulations and from ±0.32 to ±0.09 dB/cm-MHz in the experiments. These results indicate that accounting for elevational diffraction reduces bias in reference-phantom-free ACS estimation in STA imaging.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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.
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 teacher head, 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".