Iterative technique for the synthesis of optical-correlation filters

The fringe-adjusted joint transform correlation (FJTC) technique has been widely used for real-time optical pattern recognition applications. However, the classical FJTC technique suffers from target distortions due to noise, scale, rotation and illumination variations of the targets in input scenes. Several improvements of the FJTC have been proposed in the literature to accommodate these problems. Some popular techniques such as synthetic discriminant function (SDF) based FJTC was designed to alleviate the problems of scale and rotation variations of the target, whereas wavelet based FJTC has been found to yield better performance for noisy targets in the input scenes. While these techniques integrated with specific features to improve performance of the FJTC, a unified and synergistic approach to equip the FJTC with robust features is yet to be done. Thus, in this paper, a robust FJTC technique based on sequential filtering approach is proposed. The proposed method is developed in such a way that it is insensitive to rotation, scale, noise and illumination variations of the targets. Specifically, local phase (LP) features from monogenic signal is utilized to reduce the effect of background illumination thereby achieving illumination invariance. The SDF is implemented to achieve rotation and scale invariance, whereas the logarithmic fringe-adjusted filter (LFAF) is employed to reduce the noise effect. The proposed technique can be used as a real-time region-of-interest detector in wide-area surveillance for automatic object detection. The feasibility of the proposed technique has been tested on aerial imagery and has observed promising performance in detection accuracy.

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“…( , ), = 1, 2, … , , an iterative procedure [12] based on the Newton-Raphson algorithm is used. Then the synthesis coefficients ( = 1, 2, . .…”

Section: Sdf-based Lpfjtcmentioning

confidence: 99%

A robust fringe-adjusted joint transform correlator for efficient object detection

2015

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“…Many other correlation filtering schemes have been proposed that are well suited for certain target recognition problems but do not meet these criteria. Some noteworthy examples include lock-and-tumbler filters, proposed by Schils and Sweeney, 22,23 which look for points of constancy among multiple outputs rather than maximum height, and linear phase coefficient composite filters ͑LPCCFs͒, proposed by Hassebrook et al, 24 which select only those training images that yield a near-Toeplitz inner-product matrix in order to achieve rotation invariance. We realize that our survey may exclude some filter designs in the literature that meet the preceding criteria; however, we believe that we have included those filters that have received significant attention from the ATR community in recent years.…”

Section: Summary Of Included Designsmentioning

confidence: 99%

Selecting a composite correlation filter design: a survey and comparative study

Kerekes

Kumar

2008

Opt. Eng

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Many composite correlation filter designs have been proposed for solving a wide variety of target detection and pattern recognition problems. Due to the large number of available designs, however, it is often unclear how to select the best design for a particular application. We present a theoretical survey and an empirical comparison of several popular composite correlation filter designs. Using a database of rotational target imagery, we show that some such filter designs appear to be better choices than others under computational and performance constraints. We compare filter performance in terms of noise tolerance, computational load, generalization ability, and distortion in order to provide a multifaceted examination of the characteristics of various filter designs.

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“…The combination of multiple angular harmonics is usually realized by applying iterative methods on the designs of diffractive optical elements (DOEs). 18,19 Recently, we developed an iterative error-reduction algorithm operating on the power spectrum over OAM-states. 2,13 A phase mask optimized by the algorithm is able to convert an incoming TEM 00 laser mode into a collinear superposition of multiple OAM-states.…”

Section: Error-reduction Algorithmmentioning

confidence: 99%

Orbital angular momentum (OAM) multiplexing in free-space optical data transfer

2006

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In the optical wireless communication systems proposed by Gibson, et al 1 , the information is encoded as states of orbital angular momentum (OAM) of light and the transmitter unit can produce laser beam with single OAM-state in a timeslot. Recently we have proved that it is possible to generate multiple OAM-states simultaneously by single spatial light modulator 2 . This method is adopted in our free-space optical wireless communication system and these OAM-states can be detected in the receiving unit by a computer-generated hologram. Hence, the transmission capacity is enhanced significantly without increasing the complexity of system.

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Iterative technique for the synthesis of optical-correlation filters

Cited by 47 publications

References 17 publications

A robust fringe-adjusted joint transform correlator for efficient object detection

A robust fringe-adjusted joint transform correlator for efficient object detection

Selecting a composite correlation filter design: a survey and comparative study

Orbital angular momentum (OAM) multiplexing in free-space optical data transfer

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