New here? Read the 7-step manual first. This is Crossing Watch as a school would use it. Step 1 is the real tool, working here in your browser. Steps 2 and 3 show our real run on our college gate on 2 Nov 2026, as it was logged (long lines shortened). Step 4 opens the results.
Cost: about $12 of SAM per 8.6-minute video at Meta's list prices, plus about $0.02 for the agent. Faces and number plates are blurred.
Step 1 · works here, no key
Mark the road: pixels become metres.
What happensMark the 4 corners of a measured rectangle on the road with anything bright the camera can see clearly: A4 paper, chalk, a bright cloth. Film it, load one frame, click the 4 markers, type the sizes. The tool turns the picture into a road map in metres, so speeds and gaps can be measured.
Faces in the sample frame are blurred. The tool runs in your browser; nothing is uploaded. Best on a laptop.
Step 2 · needs a Meta Model API key
Run it: Meta's models do the seeing.
What happensSAM 3.1 tracks people and vehicles; code measures who reached the same spot how many seconds apart; Muse Spark looks at each person in a near-miss and removes riders and things that are not people. Below are lines from our real run's log, in order (long lines cut where marked ...).
Replay · our run log, 2 Nov 2026
The funnel75 raw near-miss candidates → Muse Spark checks each person (one more ruled out by eye) → 5 kept → 2 serious and 3 close passes. The two highlighted lines are 2 of the ones Muse Spark removed: a person who was riding the bike, and something that was not a person.
About $12 of SAM for an 8.6-minute video at Meta's list prices. Python 3.11+ and ffmpeg; code on GitHub.
Step 3 · the case agent, on Muse Spark
The agent checks itself: it asks for a tape measure.
What happensBefore it trusts a single metre, the agent stops and asks a person to measure a second line with a tape, one the maths never used. If the video and the tape agree, the letter goes ahead; then it waits for the head of the school. This is the real log.
Replay · the agent's log, 2 Nov 2026
Five agent turns, about $0.02 in all. The full log.
Step 4 · results
The evidence, ready to send.
What happensEvery near-miss with its blurred clip, a road map in metres, the fix drawn by Muse Image, and a letter whose every number is checked by code. Our college certified this report genuine on 3 Nov 2026.
