New Open-Source Tool Fixes the Hidden Refraction Errors That Warp

A new open-source package, AquaCal, published in SoftwareX, aims to correct a common calibration error in multi-camera systems that image through water or other refractive interfaces. Standard multi-camera calibration assumes light travels in straight lines, an assumption built into the pinhole camera model used by most 3D reconstruction pipelines. But when rays cross an air-water boundary, refraction depends on the incident angle, warping triangulated positions, velocities, and distance estimates. Earlier work showed residual depth errors that can reach several percent of camera-to-point distance and about 20 cm error at 2 m. AquaCal provides a rigorously tested correction for a widely used geometry, improving accuracy without obvious warning signs in usual checks.