Abdul Ahad S. Awwal

Improved correlation discrimination using an amplitude-modulated phase-only filter

A novel amplitude-modulated phase-only filter (AMPOF) is proposed for achieving improved correlation discrimination. The proposed AMPOF has an amplitude spectrum which is the inverse of a biased amplitude spectrum of the object function and a phase spectrum which is a complex conjugate of the phase spectrum of the object function. When compared with the phase-only filters, the AMPOF is found to have significantly superior correlation discrimination capability.

Polarization-encoded optical shadow-casting logic units: design

A general design algorithm is presented for the multioutput polarization-encoded optical shadow-casting scheme. A set of POSC equations is obtained from the truth table of the desired logic unit and is solved in terms of four possible pixel characteristics (transparent, opaque, vertically polarized, and horizontally polarized) and four possible source characteristics (off, unpolarized, vertically polarized, and horizontally polarized). To demonstrate its feasibility, the algorithm is used to determine the input pixel characteristics of a full adder and a full subtracter.

Polarization-encoded optical shadow-casting scheme: design of multioutput trinary combinational logic units.

The input encoding algorithm of the polarization-encoded optical shadow-casting (POSC) scheme is modified to include the design of trinary combinational logic units. For illustration, the modified algorithm is deterministically employed in the design of trinary adders. Two design approaches are examined for identifying the constraints and flexibilities that are encountered depending on whether the zero-output conditions are considered. The more complicated POSC overlap equations are handled by incorporating LED source encoding to the input encoding process.

Polarization-encoded optical shadow-casting: direct implementation of a carry-free adder

Carry-free addition based on the redundant binary number system is adopted for the lensless polarization-encoded optical shadow-casting (POSC) system. A carry-free POSC adder is designed by determining the codings of (1) the redundant input bits for generating the intermediate sum and intermediate carry and (2) the intermediate sum and intermediate carry for generating the carry-free sum.

Polarization-encoded optical shadow-casting programmable logic array: simultaneous generation of multiple outputs

A scheme for designing a content-addressable memory (CAM) using polarization-encoded optical shadow-casting (POSC) is proposed. Such a programmable logic array requires comparatively less memory storage because of the built-in reduction in the truth table entries. The scheme is implemented by copying the truth table entries directly into the corresponding input pixel subcells. The proposed POSC CAM generates all its outputs simultaneously, thus eliminating the design requirement of switching either LED sources or decoding masks. For illustration, a 4-input 4-output 2x2 binary multiplication unit is designed using this scheme.

Polarization-encoded optical shadow casting: design of a J-K flip-flop

The device architecture and the corresponding codings of the inputs of a polarization-encoded optical shadow-casting J-K flip-flop are presented. Three different flip-flop designs are considered and compared.

Associative polarization-encoded optical shadow casting: gray-level image encoding for serial and parallel operations

An efficient algorithm for designing a serial and parallel multioutput logic unit using an associative polarization-encoded optical shadow-casting technique is presented. Devices designed as such have a unique contentaddressable associative memory where each of the memory locations has dual addresses. For illustration, the proposed algorithm has been used to design a serial-output and a parallel-output 2-bit gray adder.

Machine Parts Recognition Using A Trinary Associative Memory

The convergence mechanism of vectors in Hopfields neural network in relation to recognition of partially known patterns is studied in terms of both inner products and Hamming distance. It has been shown that Hamming distance should not always be used in determining the convergence of vectors. Instead, inner product weighting coefficients play a more dominant role in certain data representations for determining the convergence mechanism. A trinary neuron representation for associative memory is found to be more effective for associative recall. Applications of the trinary associative memory to reconstruct machine part images that are partially missing are demonstrated by means of computer simulation as examples of the usefulness of this approach.

Median filtering using polarization-encoded optical shadow casting

A very powerful space-variant image processing technique such as median filtering is performed using the polarization-encoded optical shadow casting (POSC) system. The POSC system is used to process two different noisy images. Two different POSC architectures and input encodings are identified and compared.

Dynamic modulation transfer function of a display system.

A theoretical model for characterizing the dynamic response of a nonscanning electrooptic display system is developed. The model interrelates the spatial frequency degradations of an image display with both phosphor characteristics and relative velocity of the displayed object. Thereafter, the analysis is extended to compare the performances of types P-20, P-42, and P-1052 phosphor based displays.