Abstract

The surfaces of large (approximately 1-m) diffusely reflecting objects can be mapped by automatic following of the holographic real image of the object. Large aperture, low f number holograms give the shallow depth of focus required for this method. The ability to apply the technique to situations requiring a pulsed laser is demonstrated. Unity magnification real images from holograms made with a Q-switched ruby laser have a measured metric fidelity of at least one part in 10⁴ over an object field of 60 deg. A sinusoidal optical interference pattern projected onto the object when the hologram is taken provides the type of contrast pattern necessary for unambiguous determination of the location of the focused image surface and facilitates automatic focus detection. The image is scanned by an image dissector that is moved about the image by a 3-axis slide system. A computer analyzes the video signals, directs the machine motions to follow the image, and provides an output of surface dimensions in digital form. A prototype machine using cw helium–neon lasers for object illumination and image reconstruction is described and performance data presented.

© 1973 Optical Society of America

Automatic Data Reduction of Certain Holographic Interferograms

M. J. Landry and C. M. Wise
Appl. Opt. 12(10) 2320-2327 (1973)

Optical Contour Mapping of Surfaces

W. Jaerisch and G. Makosch
Appl. Opt. 12(7) 1552-1557 (1973)

Heterodyne Readout for Read-Write Holographic Memories

R. S. Mezrich and W. C. Stewart
Appl. Opt. 12(11) 2677-2682 (1973)

Real-Time Holographic Motion Picture Camera Capable of Recording Front Surface Detail from a Random Velocity Vector

Robert L. Kurtz and Lawrence M. Perry
Appl. Opt. 12(12) 2815-2821 (1973)

Design Relationships for Holographic Memories

A. Vander Lugt
Appl. Opt. 12(7) 1675-1685 (1973)