Sensorless 3-D Ultrasound Reconstruction via Embedded Patterns: A Low-Cost Framework

Hand-held 3-D ultrasound (US) imaging offers critical advantages over conventional 2-D systems by providing richer spatial context and more reliable volumetric measurements for diagnosis and interventions. However, existing 3-D US solutions either rely on costly external tracking systems or suffer from cumulative drift errors in purely image-based methods. To address these limitations, we propose a novel, low-cost sensorless 3-D US framework that integrates a custom coupling device with a coarse-to-fine optimization algorithm for robust pose refinement. The coupling device embeds geometrically structured patterns into the US images, enabling accurate probe pose estimation directly from image content and supporting reliable volumetric reconstruction. Validation using simulations, phantoms, and in vivo carotid artery studies confirms the method’s accuracy: 2.4% average drift rate (ADR) in simulations, 2.4% volumetric error, and linear measurement error of 0.07, 0.11, and 0.22 mm for lateral, axial, and elevational directions in phantoms, and anatomical fidelity comparable to commercial 3-D probes in vivo. By removing the need for expensive external tracking or specialized US probes and enhancing robustness over existing image-based methods, our approach improves the accessibility of 3-D US imaging, particularly in resource-constrained clinical settings.