Rolling shutter imaging on the electric grid
Bibliographic record
Abstract
Flicker of AC-powered lights is useful for probing the electric grid and unmixing reflected contributions of different sources. Flicker has been sensed in great detail with a specially-designed camera tethered to an AC outlet. We argue that even an untethered smartphone can achieve the same task. We exploit the inter-row exposure delay of the ubiquitous rolling-shutter sensor. When pixel exposure time is kept short, this delay creates a spatiotemporal wave pattern that encodes (1) the precise capture time relative to the AC, (2) the response function of individual bulbs, and (3) the AC phase that powers them. To sense point sources, we induce the spatiotemporal wave pattern by placing a star filter or a paper diffuser in front of the camera's lens. We demonstrate several new capabilities, including: high-rate acquisition of bulb response functions from one smartphone photo; recognition of bulb type and phase from one or two images; and rendering of live flicker video, as if it came from a high speed global-shutter camera.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.002 | 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".