Papers by William T. Rhodes
With augmenting security concerns and decreasing costs of surveillance and computing equipment, r... more With augmenting security concerns and decreasing costs of surveillance and computing equipment, research on automated systems for object detection has been increasing, but the majority of the studies focus their attention on sequences where high-resolution objects are of interest. The main objective of the work reported here is the detection and extraction of information of low-resolution objects (e.g., objects that are so small or so far away from the camera that they occupy only tens of pixels) in order to provide a base for higher level information operations such as classification and behavioral analysis. The system proposed is composed of four stages (preprocessing, background modeling, information extraction, and post processing) and uses context-based region-of-importance selection, histogram equalization, background subtraction, biological motion analysis, and morphological filtering techniques. The result is a system capable of detecting and tracking low -resolution objects...
Real-Time Signal Processing for Industrial Applications
Journal of Photonics for Energy
ICASSP '76. IEEE International Conference on Acoustics, Speech, and Signal Processing
... Figure 3 illustrates in block diagram form one kind of operation that can be performed by suc... more ... Figure 3 illustrates in block diagram form one kind of operation that can be performed by such a signal processing system. In this figure, fj and rout SPECTRAL RESOLUTION MASK c; aaaaa aa a a a a 0 0 a aI a . T11T_ !1T1 ., () vvvv\ (à y LOG—MAPPING SLIT Th91— / ( ...
Materials, Devices, and Systems for Optoelectronic Processing
ABSTRACT
Effective Utilization of Optics in Radar Systems
ABSTRACT
1999 Euro-American Workshop Optoelectronic Information Processing: A Critical Review
The spatio-temporal coherence function (STCF) associated with the wavefield from a scene conveys ... more The spatio-temporal coherence function (STCF) associated with the wavefield from a scene conveys all information required to produce an image of that scene. Through the use of dynamic coding /decoding masks a STCF can be converted in form so as to allow the image-forming information to be conveyed via a single optical fiber to a remote viewing site. A general theory relating to STCF transfer is presented, and a Young's fringe-based discussion of why the scheme is plausible is presented.
Advances in Optical Information Processing I
ABSTRACT
Optical Information Processing Systems and Architectures
For the quarter of a century I have been involved in optical computing we have put forward a rath... more For the quarter of a century I have been involved in optical computing we have put forward a rather consistent set of arguments and beliefs which have led to a great increase in our numbers, knowledge, funding, and capabilities. I believe we must now challenge these basic tenants of our faith in the name of honesty and in the hope of a brighter future.
Travel: Foreign travel must have prior approval-Contact OCA in each case. Domestic travel require... more Travel: Foreign travel must have prior approval-Contact OCA in each case. Domestic travel requires sponsor approval where total will exceed greater of S500 or 125% of approved proposal budget category.
Optical and Hybrid Computing
ABSTRACT
Conference Proceedings of the Society for Experimental Mechanics Series, 2016
ABSTRACT Imaging through long-path (e.g., several km) turbulence presents difficulties that have ... more ABSTRACT Imaging through long-path (e.g., several km) turbulence presents difficulties that have until now been largely insurmountable. In this paper we describe a new active-illumination method that we think has good potential for allowing diffraction-limited imaging with large isoplanatic patch size.
Optical Engineering, 2003
Applied Optics, 1995
The rotating-kernel min-max transformation is a nonlinear image-processing operation that can be ... more The rotating-kernel min-max transformation is a nonlinear image-processing operation that can be applied to the enhancement of directional features in noisy images. Associated with a particular transformation are (a) a convolution kernel and (b) a function that maps to a final output value the maximum and minimum values measured at point (x, y) in the convolution output as the kernel rotates through 360°. Frequently used kernels are narrow in one direction and broad in the other, typically with rectangular, triangular, or Gaussian profiles in the long direction. Simple but effective functional mappings include I(out)(x, y) = [Max(x, y) - Min(x, y)] and I(out)(x, y) = {1 -[Min(x, y)/Max(x, y)](m)}. Improved results are often obtained if successive rotating-kernel min-max transformation operations are performed in cascaded systems. Two binarization procedures based on the rotating-kernel min-max transformation can be used to extract straight-line features from noisy gray-scale images. The effects on the processed image of kernel type and size, mapping function, and binarization scheme are discussed.
ABSTRACT Various schemes have been investigated that facilitate the imaging of objects viewed thr... more ABSTRACT Various schemes have been investigated that facilitate the imaging of objects viewed through time-varying scattering elements such as the atmosphere. Analyses we have performed in connection with enhanced-backscatter imaging and a particular class of superresolving imaging systems have led to a general principle that describes the transfer of the coherence properties of a wavefield that passes twice (double-passage) through a dynamic scatterer. Restoration of the coherence properties of the wave allow the formation of images with light that has been doubly scattered. Analyses are presented for the enhanced-backscatter, superresolution, and general case, and brief remarks presented regarding the possible application of the principle to remote image formation through the turbulent atmospheric.
Proceedings of Leos 94, 1994
Georgia Institute of Technology Final Report, Nov 1, 1981
Applied Optics, May 1, 1988
Optical hardware for symbolic substitution is under serious consideration for parallel optical co... more Optical hardware for symbolic substitution is under serious consideration for parallel optical computing applications. Symbolic substitution replaces chosen patterns of ones and zeros in a binary array with other chosen patterns of ones and zeros. Implemented with specialized substitution rules, symbolic substitution can be applied to the processing of imges that are represented in binary form. Important operations investigated in this paper are (1) nonlinear filtering operations applied to shapes (morphological transformations, including erosion, dilation, opening, closing) and (2) linear filtering operations applied to binary digital representations of continuous-tone images. Examples presented include a nonlinear noise-removal operation, thresholding, a gradient operator, and convolution. The results of an engineering study of system complexity for linear filtering operations are also presented. patterns of ones and zeros in an array into other 2-D patterns of ones and zeros. Symbolic substitution can be used to perform all the basic Boolean logic operations; hence SS-based computers are capable of performing all operations performed by contemporary general-purpose computers. Moreover, because of its characteristic parallelism and spatial-pattern orientation, SS appears particularly attractive for implementing image processing algorithms. It is the purpose of this paper to report on initial investigations into such processing. We consider two classes of image processing operations. In the first, SS is applied to two-toned imagesshapes-to perform structure modifications (often described as mathematical morphology 6) such as erosion, dilation, opening, and closing. Then SS is applied to the numerical processing of sampled and digitized continuous-tone images. Specialized SS rules and algorithms are developed for specific image processing tasks, including thresholding, small kernel operations, and convolution.
Appl Opt, 1993
A partially coherent system is introduced for defect inspection of periodic objects such as integ... more A partially coherent system is introduced for defect inspection of periodic objects such as integrated circuit photomasks. An experimental investigation demonstrates that the new system is more robust in the presence of optical setup noise than the corresponding coherent spatial filtering system. The system illumination is provided by an array of mutually incoherent point sources that image onto a grid of opaque spots at the pupil plane. Nonperiodic defects are displayed at the image plane as bright structures against a dark background.
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Papers by William T. Rhodes