Deictic

Prior work disclosure

Deictic is a pre-existing project developed before EurekaDev 2026. I am entering it as previously built work, not claiming it was created during this event. EurekaDev notes that projects built before its event window receive a substantial score deduction.

What it does

Deictic resolves vague references in STEM lecture captions to the exact visual item on screen. For example, it can turn “Now this becomes negative” into a clickable reference to the −v₀ term in an equation, selected over other plausible items in the lecture frame.

How it works

The seeded demo uses deterministic, inspectable code, not a trained model. It ranks candidate targets using five signals: timing, phrase type, words matched to visible notation, position, and a deliberately weak size prior. The inspector shows the ranked candidates and signal breakdown, and the viewer measures target boxes from the rendered frame so highlights stay aligned.

Validation

On authored, synthetic fixtures, Deictic resolves 10/10 references in a mechanics lecture and 6/6 in an energy-transfer lecture. These are fixture results, not real-world accuracy claims. The repository includes 28 tests, a naive baseline, adversarial replay, and geometry checks.

How it was built

The project uses Next.js, React, and TypeScript. The public seeded judge path runs without a login, API key, or external service. A separate custom-video lab can call a configured server-side vision provider; that optional path is not used for the seeded results.

Challenges and learning

A key challenge was avoiding a trivial 10/10 result from frames with only one possible target. The fixtures now include competing equation terms, notes, and diagram regions, and a simple “largest nearby target” baseline runs alongside the resolver. That baseline gets 7/10 wrong on the mechanics fixture. I learned to make the evidence inspectable: the demo exposes candidate rankings, adversarial re-resolution, and measured box overlap instead of presenting a score without its test setup.

Built With

• next.js
• react
• typescript