Richard E. Twogood

Design of stable 2-D half-plane recursive filters using spectral factorization

In this paper a new design algorithm for two-dimensional (2-D) recursive digital filters is presented, with emphasis on the general class of half-plane filters. A recently developed 2-D spectral factorization procedure and a nonlinear optimization algorithm are incorporated to iteratively converge to a stable, (locally) optimum filter. Details of the computations required in the implementation of the design procedure are presented, in addition to an example of its application.

Best Linear Decoding of Random Mask Images

In 1968 Dicke proposed coded imaging of x and ¿ rays via random pinholes. Since then, many authors have agreed with him that this technique can offer significant image improvement. We present a best linear decoding of the coded image and show its superiority over the conventional matched filter decoding. Experimental results in the visible light region are presented.

Why filter recursively in two dimensions

The relative advantages of 2-D recursive digital filters over their nonrecursive counterparts are discussed. A design example illustrates the ability of 2-D recursive filters to yield excellent responses with far fewer coefficients than nonrecursive filters require. This difficulty is seen to be partially overcome by using nonrecursive filters with very efficient implementations.

2-D Digital signal processing with an array processor

The applicability of array processor (AP) technology to 2-D digital signal processing is investigated in this paper. The AP-based image processing facility at LLL is described, with emphasis on our applications software Package which utilizes the array processor. Implementations of several key image processing algorithms are discussed and compared with other conventional processors, indicating that array processors are extremely cost-effective for image processing applications.