Computer vision for focus calibration of photo-polymerization systems

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsResearchpeer-review

Abstract

Photopolymerization by mask projection allow for rapid construction of extremely detailed and intricate objects, such as hearing aids. The Technical University of Denmark has long had an interest in applying computervision systems to additive manufacturing systems to increase quality. To obtain the optimal quality for photopolymerization systems, it is paramount that the focal plane is exactly at the build plane. Manually finding the position with optimal focus is an arduous and time-consuming task. Previous attempts at implementing an automatic procedure for finding the optimum focus has failed [1].
In this paper we present an autofocusing solution formask projection based photopolymerisation systems(MPPSs), with ease-of-use equivalent to the autofocus known from an ordinary DSLR-camera. The autofocusing solution has been implemented and tested on the experimental MPPS (Figure 1) at Technical University of Denmark, Department of Mechanical Engineering using a PointGrey Blackfly S BFS-U3-51S5M-C industrial CCD-camera, no lens and pixel size of 3:45μm.The MPPS is built using a Visitech Luxbeam RapidSystem projector of LRS-WQ-HY, with a micromirror size of 7:5μm and depth-of-focus range of ±50μm for the 1:0 magnification filter and ±200μm for the 2:0 magnification filter [2], [3]. The lateral movement of the projector is designed with a motorized projector mount to have a minimum step size of 1:56μm. By projecting an image from the projector up onto the glass plate where the camera is mounted and moving the projector laterally, we are able to implement autofocus. Our autofocus solution allows researchers faster and easier access to building on the MPPS, requiring no training in using calibration software or printer operating procedure outside the standard.
Original languageEnglish
Title of host publicationProceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing
PublisherAmerican Society for Precision Engineering
Publication date2018
Pages89-91
ISBN (Electronic)978-188770676-6
Publication statusPublished - 2018
Event2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing - Lawrence Berkeley National Laboratory, Berkeley, United States
Duration: 22 Jul 201825 Jul 2018

Conference

Conference2018 ASPE and euspen Summer Topical Meeting
LocationLawrence Berkeley National Laboratory
CountryUnited States
CityBerkeley
Period22/07/201825/07/2018
OtherJoint Special Interest Group meeting: Additive Manufacturing

Cite this

Ingwersen, C. K., Mortensen, H. L., Ribo, M. M., Danielak, A. H., Eiríksson, E. R., Nielsen, A. A., & Pedersen, D. B. (2018). Computer vision for focus calibration of photo-polymerization systems. In Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing (pp. 89-91). American Society for Precision Engineering.
Ingwersen, Christian K. ; Mortensen, Harald L. ; Ribo, Macarena M. ; Danielak, Anna H. ; Eiríksson, Eyþór R. ; Nielsen, Allan A. ; Pedersen, David B. / Computer vision for focus calibration of photo-polymerization systems. Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing. American Society for Precision Engineering, 2018. pp. 89-91
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abstract = "Photopolymerization by mask projection allow for rapid construction of extremely detailed and intricate objects, such as hearing aids. The Technical University of Denmark has long had an interest in applying computervision systems to additive manufacturing systems to increase quality. To obtain the optimal quality for photopolymerization systems, it is paramount that the focal plane is exactly at the build plane. Manually finding the position with optimal focus is an arduous and time-consuming task. Previous attempts at implementing an automatic procedure for finding the optimum focus has failed [1]. In this paper we present an autofocusing solution formask projection based photopolymerisation systems(MPPSs), with ease-of-use equivalent to the autofocus known from an ordinary DSLR-camera. The autofocusing solution has been implemented and tested on the experimental MPPS (Figure 1) at Technical University of Denmark, Department of Mechanical Engineering using a PointGrey Blackfly S BFS-U3-51S5M-C industrial CCD-camera, no lens and pixel size of 3:45μm.The MPPS is built using a Visitech Luxbeam RapidSystem projector of LRS-WQ-HY, with a micromirror size of 7:5μm and depth-of-focus range of ±50μm for the 1:0 magnification filter and ±200μm for the 2:0 magnification filter [2], [3]. The lateral movement of the projector is designed with a motorized projector mount to have a minimum step size of 1:56μm. By projecting an image from the projector up onto the glass plate where the camera is mounted and moving the projector laterally, we are able to implement autofocus. Our autofocus solution allows researchers faster and easier access to building on the MPPS, requiring no training in using calibration software or printer operating procedure outside the standard.",
author = "Ingwersen, {Christian K.} and Mortensen, {Harald L.} and Ribo, {Macarena M.} and Danielak, {Anna H.} and Eir{\'i}ksson, {Ey{\th}{\'o}r R.} and Nielsen, {Allan A.} and Pedersen, {David B.}",
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booktitle = "Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing",
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Ingwersen, CK, Mortensen, HL, Ribo, MM, Danielak, AH, Eiríksson, ER, Nielsen, AA & Pedersen, DB 2018, Computer vision for focus calibration of photo-polymerization systems. in Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing. American Society for Precision Engineering, pp. 89-91, 2018 ASPE and euspen Summer Topical Meeting, Berkeley, United States, 22/07/2018.

Computer vision for focus calibration of photo-polymerization systems. / Ingwersen, Christian K. ; Mortensen, Harald L. ; Ribo, Macarena M.; Danielak, Anna H.; Eiríksson, Eyþór R.; Nielsen, Allan A.; Pedersen, David B.

Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing. American Society for Precision Engineering, 2018. p. 89-91.

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsResearchpeer-review

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T1 - Computer vision for focus calibration of photo-polymerization systems

AU - Ingwersen, Christian K.

AU - Mortensen, Harald L.

AU - Ribo, Macarena M.

AU - Danielak, Anna H.

AU - Eiríksson, Eyþór R.

AU - Nielsen, Allan A.

AU - Pedersen, David B.

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N2 - Photopolymerization by mask projection allow for rapid construction of extremely detailed and intricate objects, such as hearing aids. The Technical University of Denmark has long had an interest in applying computervision systems to additive manufacturing systems to increase quality. To obtain the optimal quality for photopolymerization systems, it is paramount that the focal plane is exactly at the build plane. Manually finding the position with optimal focus is an arduous and time-consuming task. Previous attempts at implementing an automatic procedure for finding the optimum focus has failed [1]. In this paper we present an autofocusing solution formask projection based photopolymerisation systems(MPPSs), with ease-of-use equivalent to the autofocus known from an ordinary DSLR-camera. The autofocusing solution has been implemented and tested on the experimental MPPS (Figure 1) at Technical University of Denmark, Department of Mechanical Engineering using a PointGrey Blackfly S BFS-U3-51S5M-C industrial CCD-camera, no lens and pixel size of 3:45μm.The MPPS is built using a Visitech Luxbeam RapidSystem projector of LRS-WQ-HY, with a micromirror size of 7:5μm and depth-of-focus range of ±50μm for the 1:0 magnification filter and ±200μm for the 2:0 magnification filter [2], [3]. The lateral movement of the projector is designed with a motorized projector mount to have a minimum step size of 1:56μm. By projecting an image from the projector up onto the glass plate where the camera is mounted and moving the projector laterally, we are able to implement autofocus. Our autofocus solution allows researchers faster and easier access to building on the MPPS, requiring no training in using calibration software or printer operating procedure outside the standard.

AB - Photopolymerization by mask projection allow for rapid construction of extremely detailed and intricate objects, such as hearing aids. The Technical University of Denmark has long had an interest in applying computervision systems to additive manufacturing systems to increase quality. To obtain the optimal quality for photopolymerization systems, it is paramount that the focal plane is exactly at the build plane. Manually finding the position with optimal focus is an arduous and time-consuming task. Previous attempts at implementing an automatic procedure for finding the optimum focus has failed [1]. In this paper we present an autofocusing solution formask projection based photopolymerisation systems(MPPSs), with ease-of-use equivalent to the autofocus known from an ordinary DSLR-camera. The autofocusing solution has been implemented and tested on the experimental MPPS (Figure 1) at Technical University of Denmark, Department of Mechanical Engineering using a PointGrey Blackfly S BFS-U3-51S5M-C industrial CCD-camera, no lens and pixel size of 3:45μm.The MPPS is built using a Visitech Luxbeam RapidSystem projector of LRS-WQ-HY, with a micromirror size of 7:5μm and depth-of-focus range of ±50μm for the 1:0 magnification filter and ±200μm for the 2:0 magnification filter [2], [3]. The lateral movement of the projector is designed with a motorized projector mount to have a minimum step size of 1:56μm. By projecting an image from the projector up onto the glass plate where the camera is mounted and moving the projector laterally, we are able to implement autofocus. Our autofocus solution allows researchers faster and easier access to building on the MPPS, requiring no training in using calibration software or printer operating procedure outside the standard.

M3 - Conference abstract in proceedings

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EP - 91

BT - Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing

PB - American Society for Precision Engineering

ER -

Ingwersen CK, Mortensen HL, Ribo MM, Danielak AH, Eiríksson ER, Nielsen AA et al. Computer vision for focus calibration of photo-polymerization systems. In Proceedings - 2018 ASPE and euspen Summer Topical Meeting: Advancing Precision in Additive Manufacturing. American Society for Precision Engineering. 2018. p. 89-91