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This paper presents a novel technique to achieve autofocusing for a three-dimensional (3D) profilometry system with dual projectors. The proposed system uses a camera that is attached with an electronically focus-tunable lens (ETL) that allows dynamic change of camera’s focal plane such that the camera can focus on the object; the camera captures fringe patterns projected by each projector to establish corresponding points between two projectors, and two pre-calibrated projectors form triangulation for 3D reconstruction. We pre-calibrate the relationship between the depth and the current being used for each focal plane, perform a 3D shape measurement with an unknown focus level, and calculate the desired current value based on the initial 3D result. We developed a prototype system that can automatically focus on an object positioned between 450 mm to 850 mm.
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Autofocusing method for high-resolution three-dimensional profilometry
State-of-the-art high-accuracy three-dimensional (3D) profilometry systems typically use a lens with a fixed focal length, making it difficult for them to measure scenes with large depth variations, especially dynamically changing ones. To address this need, this Letter proposes a novel, to the best of our knowledge, autofocusing method for high-resolution 3D profilometry with a digital fringe projection technique by (1) developing a novel continuous geometric parameter model for systems using electrically tunable lenses and (2) employing a focal plane detection algorithm. The validity of the proposed method is confirmed by experiments.
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- Award ID(s):
- 1637961
- PAR ID:
- 10130162
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Letters
- Volume:
- 45
- Issue:
- 2
- ISSN:
- 0146-9592; OPLEDP
- Format(s):
- Medium: X Size: Article No. 375
- Size(s):
- Article No. 375
- Sponsoring Org:
- National Science Foundation
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