Conoscopic holography based profilometers for defect inspection: improviements in speed, resolution, and noise reduction

Ignacio Álvarez; José M. Enguita; César Fraga; Jorge Marina; Yolanda Fernández

doi:10.1117/12.661455

22 April 2006 Conoscopic holography based profilometers for defect inspection: improvements in speed, resolution, and noise reduction

Ignacio Álvarez, José M. Enguita, César Fraga, Jorge Marina, Yolanda Fernández

Author Affiliations +

Proceedings Volume 6189, Optical Sensing II; 61890H (2006) https://doi.org/10.1117/12.661455
Event: SPIE Photonics Europe, 2006, Strasbourg, France

Abstract

One of the more challenging applications of optical metrology is real-time dimensional control and surface inspection in industrial applications, where strong requirements of cost, speed of operation, ease of setup and applicability in adverse environments, greatly limit the number of applicable technologies. An optic profilometer, based on Conoscopic holography, has been designed specifically for this purpose and used in several on-line inspection systems. This device is able to obtain a distance profile of a target in a single shot; works at long distance standoff (700-1200mm) and still keeps good resolution (under 0.2mm) with a very easy and reliable setup. However, there are still some drawbacks that should be addressed. The first one is the signal processing, which is a relatively expensive process and limits the acquisition rate at no more than 70 profiles per second. The second one is speckle noise, which is an inherent problem in systems that use coherent-light illumination and triangulation, and therefor could be extrapolated to many other optical inspection systems. This paper shows the current lines of research to solve both problems and presents some initial, yet very interesting, results. These improvements can be applicable to other ranges of devices using this technology in adverse environments, for roughness and vibration measurement or surface defects detection.

Citation Download Citation

Ignacio Álvarez, José M. Enguita, César Fraga, Jorge Marina, and Yolanda Fernández "Conoscopic holography based profilometers for defect inspection: improvements in speed, resolution, and noise reduction", Proc. SPIE 6189, Optical Sensing II, 61890H (22 April 2006); https://doi.org/10.1117/12.661455

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available