# Rolling Shutter Camera Synchronization with Sub-millisecond Accuracy

## TL;DR

This paper presents a straightforward method for synchronizing multiple rolling shutter cameras with sub-millisecond accuracy, even with different frame rates and non-overlapping views, validated on sports footage.

## Contribution

The proposed approach achieves high-precision synchronization using rolling shutter properties, applicable to multiple cameras with varying parameters and lighting conditions.

## Key findings

- Synchronization accuracy with 0.3-0.5 ms error range
- Effective on cameras with different frame rates and resolutions
- Validated on ice hockey footage with fast-moving objects

## Abstract

A simple method for synchronization of video streams with a precision better than one millisecond is proposed. The method is applicable to any number of rolling shutter cameras and when a few photographic flashes or other abrupt lighting changes are present in the video. The approach exploits the rolling shutter sensor property that every sensor row starts its exposure with a small delay after the onset of the previous row. The cameras may have different frame rates and resolutions, and need not have overlapping fields of view. The method was validated on five minutes of four streams from an ice hockey match. The found transformation maps events visible in all cameras to a reference time with a standard deviation of the temporal error in the range of 0.3 to 0.5 milliseconds. The quality of the synchronization is demonstrated on temporally and spatially overlapping images of a fast moving puck observed in two cameras.