Abstract

A real-time joint Fourier transform image correlator that uses partially coherent readout illumination to perform signal detection in complex amplitude is described. The interference between the Fourier transforms of input images is obtained by coherent light. However, the correlation signal is produced by partially coherent illumination, which is used to read out the Fourier transforms interference intensity from the output of the spatial light modulator (liquid crystal image transducer). The advantage of this technique is the reduction in the spatial phase variations in the output wavefront of the image transducer. Such nonuniformities may arise from nonflatness and mismatch of various output layers in some devices that can degrade the performance of the correlator. We present experimental results to show that the phase distortion effects present in the output surface of the device can be reduced by using partially coherent readout illumination. It is also shown that the correlation bandwidth obtained by the proposed system is smaller compared to VanderLugt filtering under quasi-monochromatic illumination. As a result, a brighter correlation peak intensity is produced, and a better correlation SNR is obtained. Pattern recognition experiments using naturally illuminated real objects are presented, and the effects of relaxed coherence on the real-time joint transform correlator is determined.

© 1987 Optical Society of America

Full Article  |  PDF Article

Corrections

B. Javidi, "Real-time joint transform correlation by partially coherent readout illumination: erratum," Appl. Opt. 28, 1054-1054 (1989)
http://proxy.osapublishing.org/ao/abstract.cfm?uri=ao-28-6-1054

OSA Recommended Articles
Real-time image recognition by partially coherent light

Bahram Javidi and Francis T. S. Yu
Appl. Opt. 25(14) 2365-2371 (1986)

Real-time joint transform correlation with photoanisotropic dye–polymer films

Tizhi Huang and Kelvin H. Wagner
Appl. Opt. 33(32) 7634-7645 (1994)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (16)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (16)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription