Browsing by Author "Khoo, I-Hung"

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2-D Digital Filter Architectures without Global Broadcast and Some Symmetry Applications
(2009)
Khoo, I-Hung
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Reddy, Hari C.
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Van, Lan-Da
;
Lin, Chin-Teng
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資訊工程學系
Four new 2-D filter VLSI architectures without global broadcast are presented. The first is a transposed systolic structure which requires fewer delay elements compared to the original systolic structure in [1]. By combining the sub-blocks of the original with the new transposed structure, two additional systolic structures are obtained to realize transfer functions with separable denominators, which require fewer multipliers. These separable denominator structures have important symmetry applications. A structure which possesses diagonal symmetry is then shown which requires even fewer multipliers.
Area-Efficient 2-D Digital Filter Architectures Possessing Diagonal and Four-Fold Rotational Symmetries
(2013-01-01)
Chen, Pei-Yu
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Van, Lan-Da
;
Reddy, Hari C.
;
Khoo, I-Hung
;
交大名義發表
In this paper, two area-efficient two-dimensional (2-D) IIR filter architectures for 2-D transfer function with diagonal and four-fold rotational symmetries are proposed for image processing. For this purpose, two different intermediate transfer functions are applied and the corresponding two new filter architectures are obtained. Under satisfactory average error performance, we determine that the new filter structure requires less multiplier wordlength than the previously published Type-1 filter structure. With the features of less numerator multiplier wordlength and shorter critical path, the proposed diagonal and four-fold rotational symmetry filter architectures can result in 10.17% and 3.35% area reduction with respect to the published Type-1 IIR filter structures with diagonal and four-fold rotational symmetries in terms of synthesis results.
Delta discrete-time operator based realization procedure for low sensitivity sampled-data and digital ladder filters
(2008)
Khoo, I-Hung
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Reddy, Hari C.
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Moschytz, George S.
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資訊工程學系
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Department of Computer Science
A delta operator based ladder synthesis procedure is presented for the realization of three different types of transfer functions. The procedure overcomes the numerical problem of the conventional z-domain LDI approach when the filter poles are clustered near z=1 and does not require any s-domain polynomial transformation to achieve spectral factorization [4]. Also, the entire operation involves only rational polynomials.
Design of 2-D Digital Filters with Almost Quadrantal Symmetric Magnitude Response without 1-D Separable Denominator Factor Constraint
(2013)
Khoo, I-Hung
;
Reddy, Hari C.
;
Van, Lan-Da
;
Lin, Chin-Teng
;
資訊工程學系
A design approach is presented for 2-D digital filters possessing approximate quadrantal magnitude symmetry without the constraint of the denominator having only 1-D separable factors. To ensure the BIBO stability of the filter, the planar least square inverse stabilization approach is employed. It is illustrated through design examples that the proposed approach results in filters with sharper transition band and lower error relative to the given filter specifications. Also, for certain cases, it is shown that a lower order non-separable denominator design can achieve the same result as a higher order separable denominator design, thus providing savings in the number of multipliers. Finally, 2-D VLSI realizations without global broadcast are presented for the optimized transfer function with non-separable denominator factors and approximate quadrantal symmetry.
Efficient design of delta operator based 2-D IIR filters using symmetrical decomposition
(2008)
Khoo, I-Hung
;
Reddy, Hari C.
;
Rajan, P. K.
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資訊工程學系
;
Department of Computer Science
A method based on symmetrical decomposition is presented for the design of 2-D IIR filters through optimization. This technique allows a filter with non-symmetric magnitude specification to benefit from the savings in parameters provided by symmetry. The procedure is developed for the delta operator based design to take advantage of its better coefficient sensitivity compared to the z-domain design when the filter is narrowband.
Generalized Formulation of 2-D Filter Structures without Global Broadcast for VLSI Implementation
(2010)
Khoo, I-Hung
;
Reddy, Hari C.
;
Van, Lan-Da
;
Lin, Chin-Teng
;
資訊工程學系
A generalized formulation is developed that allows the derivation of various new 2-D VLSI filter structures, without global broadcast, using different filter sub-blocks and their interconnections (frameworks). With this formulation, lattice-type and direct-form structures realizing general 2-D IIR and FIR transfer functions, IIR transfer functions with separable denominators, and transfer functions with quadrantal magnitude symmetry are easily obtained. The separable denominator and quadrantal symmetry structures have the advantage of reduced number of multipliers.
Power-Efficient and Cost-Effective 2-D Symmetry Filter Architectures
(2011-01-01)
Chen, Pei-Yu
;
Van, Lan-Da
;
Khoo, I-Hung
;
Reddy, Hari C.
;
Lin, Chin-Teng
This paper presents two-dimensional (2-D) VLSI digital filter structures possessing various symmetries in the filter magnitude response. For this purpose, four Type-1 and four Type-2 power-efficient and cost-effective 2-D magnitude symmetry filter architectures possessing diagonal, fourfold rotational, quadrantal, and octagonal symmetries with reduced number of multipliers and one power-efficient and cost-effective multimode 2-D symmetry filter are given. By combining the identities of the four Type-1 symmetry filter structures, the proposed multimode 2-D symmetry filter is capable of providing four different operation modes: diagonal symmetry mode (DSM), fourfold rotational symmetry mode (FRSM), quadrantal symmetry mode (QSM), and octagonal symmetry mode (OSM). The proposed diagonal, fourfold rotational, quadrantal, and octagonal symmetry filter structures can attain power savings of 16.77%, 36.30%, 22.90%, and 37.73% with respect to that of the conventional 2-D filter design without symmetry. On the other hand, the proposed DSM, FRSM, QSM, and OSM modes can reduce power consumption by 11.01%, 31.42%, 17.53%, and 35.26% compared with that of the conventional 2-D filter design. The proposed multimode filter can result in a 63.25% area reduction compared with the sum of the areas of the four individual Type-1 symmetry filter structures.
Symmetry Incorporated Cost-Effective Architectures for Two-Dimensional Digital Filters
(2019-01-01)
Van, Lan-Da
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Khoo, I-Hung
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Chen, Pei-Yu
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Reddy, Haranatha (Hari) C.
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交大名義發表
Professor Fettweis as far back as 1977 published a paper generalizing McClellan transformation to obtain circular symmetry in 2-D and spherical, hyper-spherical symmetries in multidimensional digital filters [1]. This survey paper presents state-of-the-art two-dimensional (2-D) VLSI digital filter architectures possessing various symmetries in the filter magnitude response. Preceding the symmetry structures, a generalized formulation is given that allows the derivation of various new 2-D VLSI filter structures of any order without global broadcast. Following this, two types (namely, Type 1 [20] and Type 3 [21], [25], [26]) of cost-effective 2-D magnitude symmetry filter architectures possessing diagonal, four-fold rotational, quadrantal, and octagonal symmetries with reduced number of multipliers are given. By combining the identities of the Types-1 and 3 symmetry filter structures, multimode 2-D symmetry filters which enable the above four symmetry modes are discussed. The Type-1 and Type-3 multimode filters can result in a 65.3% cost reduction in terms of number of multipliers compared with the sum of the multipliers of the four individual Type-1 symmetry filter structures studied in this paper. Furthermore, Type-3 has shorter critical path than Type-1 multimode filter. The paper is concluded with the presentation of a 2-D filter design example and a corresponding structure.