A compact LED-based phase measuring deflectometry setup

Petri Lehtonen, Yuankun Liu

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

2 Citations (Scopus)


A compact LED illumination based shape measurement system of glossy surfaces is presented. The system is based on Phase Measuring Deflectometry (PMD). In this system the sinusoidal fringe pattern is formed using photographic 35 mm film frame which is illuminated from behind using LED and diffuser. A beam splitter is used to combine x- and y-direction fringe patterns, which are needed by PMD. Phase shifting is generated manually using translational stages and micrometer actuators. Compared to digital fringes displayed on the screen, our LED based setup can provide higher power, completely diffuse light and produce smoother sinusoidal fringes with continuous intensity distribution. LED usage enables also pulsed illumination to freeze sample movement. The resolution of the method is submicron level. Due to the compact size this setup is promising in the small scale measurement field.
Original languageEnglish
Title of host publicationInterferometry XV: Techniques and Analysis
EditorsCatherine E. Towers, Joanna Schmit, Katherine Creath
Place of PublicationBellingham, USA
PublisherInternational Society for Optics and Photonics SPIE
Number of pages7
ISBN (Print)9780819482860
Publication statusPublished - 2010
MoE publication typeA4 Article in a conference publication
EventInterferometry XV: Techniques and Analysis - San Diego, United States
Duration: 2 Aug 20104 Aug 2010

Publication series

SeriesProceedings of SPIE


ConferenceInterferometry XV: Techniques and Analysis
Country/TerritoryUnited States
CitySan Diego


  • Phase Measuring Deflectometry
  • PMD
  • LED
  • surface shape measurement
  • glossy surface
  • free-form mirror
  • sinusoidal fringe
  • film frame


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