Papers by Ricardo Queiroz
H.264/AVC is the newest, state-of-the-art, video compression standard. Recently adopted, it leads... more H.264/AVC is the newest, state-of-the-art, video compression standard. Recently adopted, it leads to substantial performance improvement compared to other existing standards. In this paper we want to explore less known features of the H.264/AVC that were not the main intent of the standard. We begin by showing a few comparisons as examples of how the H.264/AVC outperforms other coders. Nevertheless, along with better video compression, the H.264/AVC brought us a few unexpected bonuses. H.264/AVC's intra-frame coder is so efficient that we can make it operate as a still image coder that outperforms the existing state-of-the-art still image compression standard (JPEG-2000). For that to work, one has to operate the H.264/AVC in intra frame and compress a single frame. Many results are shown comparing it with JPEG-2000 for still image compression. In effect, the intra-frame prediction mode is so efficient that interframe prediction can be simplified if necessary. We will show that one can turn off motion estimation and yet H.264/AVC can outperform MPEG-2. For that, we simply set all motion vectors to be zero. The interframe prediction is made to "compete" with the intraframe predictions. Results are presented to demonstrate the superiority of H.264/AVC with no motion estimation against MPEG-2 for sequences with moderate motion.
Journal of Visual Communication and Image Representation, 1995
IEEE Transactions on Signal Processing, 2000
A lattice structure for an -channel linear-phase perfect reconstruction filter bank (LPPRFB) base... more A lattice structure for an -channel linear-phase perfect reconstruction filter bank (LPPRFB) based on the singular value decomposition (SVD) is introduced. The lattice can be proven to use a minimal number of delay elements and to completely span a large class of LPPRFB's: All analysis and synthesis filters have the same FIR length, sharing the same center of symmetry. The lattice also structurally enforces both linear-phase and perfect reconstruction properties, is capable of providing fast and efficient implementation, and avoids the costly matrix inversion problem in the optimization process. From a block transform perspective, the new lattice can be viewed as representing a family of generalized lapped biorthogonal transform (GLBT) with an arbitrary number of channels and arbitrarily large overlap. The relaxation of the orthogonal constraint allows the GLBT to have significantly different analysis and synthesis basis functions, which can then be tailored appropriately to fit a particular application. Several design examples are presented along with a high-performance GLBT-based progressive image coder to demonstrate the potential of the new transforms.
IEEE Transactions on Image Processing, 2000
Compound document images contain graphic or textual content along with pictures. They are a very ... more Compound document images contain graphic or textual content along with pictures. They are a very common form of documents, found in magazines, brochures, Web sites, etc. We focus our attention on the mixed raster content (MRC) multilayer approach for compound image compression. We study block thresholding as a means to segment an image for MRC. An attempt is made to optimize the block threshold in a rate-distortion sense. Also, a fast algorithm is presented to approximate the optimized method. Extensive results are presented including rate-distortion curves, segmentation masks and reconstructed images, showing the performance of the proposed algorithm
IEEE Transactions on Signal Processing, 1996
The general factorization of a linear-phase paraunitary filter bank (LPPUFB) is revisited. From t... more The general factorization of a linear-phase paraunitary filter bank (LPPUFB) is revisited. From this new perspective, a class of lapped orthogonal transforms with extended overlap (generalized linear-phase lapped orthogonal transforms (GenLOT's)) is developed as a subclass of the general class of LPPUFB. In this formulation, the discrete cosine transform (DCT) is the order-1 GenLOT, the lapped orthogonal transform is the order-2 GenLOT, and so on, for any filter length that is an integer multiple of the block size. The GenLOT's are based on the DCT and have fast implementation algorithms. The implementation of GenLOT's is explained, including the method to process finite-length signals. The degrees of freedom in the design of GenLOT's are described, and design examples are presented along with image compression tests.
... Trac D. nun' Ricardo L. de Queiro2 Truong Q. Nguyen3 &#x... more ... Trac D. nun' Ricardo L. de Queiro2 Truong Q. Nguyen3 'University of Wisconsin, ECE Department, Madison, WI, 53706 2Xerox Corporation ... The relaxation of the orthogonal constraint allows the VLGLBT to have significantly different analysis and synthesis banks which can be ...
Page 1. 277 Generalized Linear-Phase Lapped Orthogonal Transforms R. L. de Queiroz&am... more Page 1. 277 Generalized Linear-Phase Lapped Orthogonal Transforms R. L. de Queiroz': T. Q. Nguyen2 and KR Rao3 electrical Engineering Department University of Texas at Arlington Box 19016, Arlington, TX, 76019 lqueiroz ...
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Papers by Ricardo Queiroz