Catadioptric Stereo on a Smartphone

TL;DR

This paper introduces a low-cost 3D printed adapter with planar mirrors that enables any smartphone to perform stereo 3D reconstruction, facilitating applications like anthropometric measurements without expensive sensors.

Contribution

The paper presents a novel, practical, and affordable stereo camera adapter for smartphones, along with calibration and experimental validation for 3D reconstruction tasks.

Findings

The adapter successfully enables stereo 3D reconstruction using standard smartphones.

Calibration identifies optimal camera-mirror angles and baseline for accurate measurements.

Demonstrated application in anthropometric measurement of human body segments.

Abstract

We present a 3D printed adapter with planar mirrors for stereo reconstruction using front and back smartphone camera. The adapter presents a practical and low-cost solution for enabling any smartphone to be used as a stereo camera, which is currently only possible using high-end phones with expensive 3D sensors. Using the prototype version of the adapter, we experiment with parameters like the angles between cameras and mirrors and the distance to each camera (the stereo baseline). We find the most convenient configuration and calibrate the stereo pair. Based on the presented preliminary analysis, we identify possible improvements in the current design. To demonstrate the working prototype, we reconstruct a 3D human pose using 2D keypoint detections from the stereo pair and evaluate extracted body lengths. The result shows that the adapter can be used for anthropometric measurement of several body segments.