KEYWORDS: Structured light, Clouds, Calibration, Receivers, Sensors, 3D metrology, Optical testing, Laser systems engineering, 3D image processing, Imaging systems
In large-scale three-dimensional (3D) coordinates measurement, to solve the problem of structured light sensor’s measurement data from different measurement stations unifying to the global coordinate system, a method based on workshop Measuring Position System (wMPS) global controlling is researched to concentrate the structured light sensor’s measurement data to the global coordinate system automatically. According to the measurement principle, two calibration methods are proposed to calibrate the structural parameters based on a standard ball, one is transferring stations based on common points and the other is fitting ball equation. Finally, a platform for experiment is built to verify the two calibration methods. Experimental results show that the average measurement error on 10 points is 0.127 mm according to the laser tracker of the first method and the other average error is 0.101 mm, both the two calibration methods have a high precision to meet the demands of large-scale 3D coordinates measurement.
Digital projector is frequently applied to generate fringe pattern in phase calculation-based three dimensional (3D) imaging systems. Digital projector often works with camera in this kind of systems so the intensity response of a projector should be linear in order to ensure the measurement precision especially in Phase-Measuring Profilometry (PMP). Some correction methods are often applied to cope with the non-linear intensity response of the digital projector. These methods usually rely on camera and gamma function is often applied to compensate the non-linear response so the correction performance is restricted by the dynamic range of camera. In addition, the gamma function is not suitable to compensate the nonmonotonicity intensity response. This paper propose a gamma correction method by the precisely detecting the optical energy instead of using a plate and camera. A photodiode with high dynamic range and linear response is used to directly capture the light optical from the digital projector. After obtaining the real gamma curve precisely by photodiode, a gray level look-up table (LUT) is generated to correct the image to be projected. Finally, this proposed method is verified experimentally.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
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.