An improved spread-spectrum method for high-frame-rate color Doppler ultrasound imaging
Bibliographic record
Abstract
We recently introduced a spread-spectrum color Doppler imaging method that produces high-resolution, highframe-rate images without the use of compounding, thereby eliminating the tradeoffs among beam quality, frame rate, and the maximum unaliased Doppler frequency that exist for standard plane-wave imaging methods. In this manuscript, we extend the spread-spectrum method to significantly reduce tissue and wall clutter compared to our original approach. Our new method partitions the transmit sequence into multiple segments, each composed of a unique random ordering of the same set of plane-wave steering angles, so each angle repeats once per segment. The Doppler ensemble is then re-arranged into a sequence with periodically repeating angles, such that stationary clutter forms a periodic slow-time signal that is removed by applying a multi-tap comb filter. The improved clutter suppression of the new method is demonstrated using Field II simulations of imaging continuous flow through an 8 mm diameter vessel with a 5 MHz linear array.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".