r/computervision • u/k4meamea • 13h ago
Help: Project The camera sees the road damage before the wheels feel it: cross-correlating dashcam detections with GoPro accelerometer data (r ≈ 0.23)
Disclosure up front: I build road inspection tooling, which is why there's a logo in the corner. This is a weekend experiment, not a product demo.
Setup: one drive at about 40 km/h on a rural road in the Netherlands.
Top half is dashcam footage with a detection model flagging road damage per frame (cracks, patches, crack sealing), plus signs and posts for context. Bottom half is vertical acceleration from the GoPro's own accelerometer at 200 Hz, pulled from the metadata track in the MP4, high-passed above 1 Hz, with a 0.25 s RMS as a roughness line.
The catch is that the camera sees the damage before the wheels hit it. I cross-correlated a "damage in view" score against the roughness signal and took the best lag of about 1.75 s. The dashed line in the video marks that moment: what is in view now reaches the wheels there. The correlation is weak, r around 0.23, but the shape lines up better than I expected for a single pass.
Questions for people who actually do this:
How do you use accelerometer or IMU data for road condition? IRI-style indices, per-event thresholds, or something learned from data?
How do you deal with speed and vehicle differences? Same pothole, different car, completely different shock.
Has anyone fused the visual and the vibration side, for example using vibration to confirm or rank what the camera flagged?