A method using a phase mask to extend the depth of field for an incoherent lens system is presented. This phase mask is designed to generate a point spread function in which the intensity distribution is invariant to misfocus. Thus, image could be retrieved by de-convoluting the misfocused one.
Its application to 3D profile sensing using point white light illumination is presented as well. A fringe pattern is projected onto the inspected surface using the point white light source. Fringe distribution is then observed by a CCD camera through the presented phase mask at a different viewpoint. Phase can be extracted by the Fourier transform method or the phase-shifting technique. With triangulation methods or proper calibration approaches, depth information can be identified from the phase of the fringes. The phase mask enlarges the depth of field of the image acquisition system, while the point white light illumination increases the depth of focus of the fringe projection system. Thus, a highly accurate, non-scanning projected fringe profilometer with large depth measuring range can be realized.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0708109-162758 |
| Date | 08 July 2009 |
| Creators | Hsu, Chun-hsiang |
| Contributors | Wei-Chia Su, Wei-Hung Su, Jung-Ping Liu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0708109-162758 |
| Rights | not_available, Copyright information available at source archive |
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