디지털 영상 처리를 위한 Quincunx 표본화가 사용된 이중 트리 이산 웨이브렛 변환 = Dual-tree Wavelet Discrete Transformation Using Quincunx Sampling For Image Processing

다국어 초록 (Multilingual Abstract)

In this paper, we explore the application of 2-D dual-tree discrete wavelet transform (DDWT), which is a directional and redundant transform, for image coding. DDWT main property is a more computationally efficient approach to shift invariance. Also, the DDWT gives much better directional selectivity when filtering multidimensional signals. The dual-tree DWT of a signal is implemented using two critically-sampled DWTs in parallel on the same data. The transform is 2-times expansive because for an N-point signal it gives 2N DWT coefficients. If the filters are designed is a specific way, then the sub-band signals of the upper DWT can be interpreted as the real part of a complex wavelet transform, and sub-band signals of the lower DWT can be interpreted as the imaginary part. The quincunx lattice is a sampling method in image processing. It treats the different directions more homogeneously than the separable two dimensional schemes. Quincunx lattice yields a non separable 2D-wavelet transform, which is also symmetric in both horizontal and vertical direction. And non-separable wavelet transformation can generate sub-images of multiple degrees rotated versions. Therefore, non-separable image processing using DDWT services good performance.

참고문헌 (Reference)

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5 Joonghee Lim, "Non-separable Image Processing Using Dual-Tree Complex Wavelet Transformation"

6 Jingyu Yang, "Image Coding Using Dual-Tree Discrete Wavelet Transform" 17 (17): 1555-1569, 2008

7 N. G. Kingsbury, "Complex wavelets for shift invariant analysis and filtering of signals" 10 (10): 234-253, 2001