The effect of transmission bandwidth on the quality of ophthalmological still and video images
Bibliographic record
Abstract
We have examined the minimum realtime transmission speed for video-angiography with the Rodenstock scanning laser ophthalmoscope (SLO) with respect to spatial and contrast resolution. An SLO fluorescein video-angiography sequence was recorded using high-quality media and relayed to a remote site at transmission speeds ranging from T3 (4.5 Mbit/s) to 0.125 T (197 kbit/s). Images were compared with each other subjectively by an ophthalmologist and objectively with image processing software. When compared qualitatively there was little difference between the T3 and T1 images. The T1 images scored well on clarity and contrast, while 0.5 T was satisfactory but inferior to T1. Transmission speeds below 0.5 T were inadequate. The digital analysis showed a slight difference between T3 and T1. We calculated that there was up to a 92% loss of resolution at 0.25 T and up to a 98% loss at 0.125 T. Based on our quantitative and qualitative analysis, a T3 line provided the highest bandwidth and best resolution, as expected. However, 0.5 T gave satisfactory results for realtime consultations and appears to be the minimum speed required for ophthalmic purposes, producing few motion artefacts and good resolution.
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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 | 0.004 | 0.025 |
| 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 | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".