Takahashi Y, Higashiguchi T, Wakayama T. Calibration for endoscopic 3D shape measurement with cone beam projection.
APPLIED OPTICS 2024;
63:3058-3068. [PMID:
38856449 DOI:
10.1364/ao.516747]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 03/17/2024] [Indexed: 06/11/2024]
Abstract
We demonstrate a calibration method for endoscopic three-dimensional shape measurement with cone beam projection. In this method, changes in the shape of the optical sectioning profiles are quantified and fitted while scanning a calibration board in the depth direction, using a cubic function. In accuracy tests using a flat plate and a ring reference gauge, the proposed method obtains an accuracy of 0.02 mm in the depth dimension and 0.09 mm in the radial dimension. These results represent 88% and 55% improvements compared to previous analysis. For medical applications, an ear examination simulator was employed, and our measurement results were compared to ground truth data obtained by microfocus X-ray computed tomography. The surface deviation of our method relative to the ground truth data was ±0.36m m during manual operation. A comparison of the measurement results before and after calibration revealed an improvement in the peak agreement with the ground truth data, with the deviation shifting from 0.2 mm to -0.05m m. Our strategy achieves a digital transformation of 3D endoscopy, which would benefit a number of medical fields.
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