Abstract. Image compression methods such as JPEG use quantisation of discrete cosine transform (DCT) coefficients of image blocks to produce lossy compression. During decoding, an inverse DCT of the quantised values is used to obtain the lossy image. These methods suffer from blocky effects from the region boundaries, and can produce poor representations of regions containing sharp edges. Such ...

In this paper, a novel contrast enhancement technique for contrast enhancement of a low-contrast satellite image has been proposed based on the singular value decomposition (SVD) and discrete cosine transform (DCT). The singular value matrix represents the intensity information of the given image and any change on the singular values change the intensity of the input image. The proposed techniq...

A new class of matrices based on a parametrization of the Feig-Winograd factorization of 8-point DCT is proposed. Such parametrization induces a matrix subspace, which unifies a number of existing methods for DCT approximation. By solving a comprehensive multicriteria optimization problem, we identified several new DCT approximations. Obtained solutions were sought to possess the following prop...

What is believed to be a new analysis algorithm to carry out profile measurement with low computational complexity and less noise sensitivity is presented. First, a discrete cosine transform (DCT)-based representation method is introduced to express the height distribution of a 3D surface. Then a novel shift estimation algorithm, called the DCT-based shift estimation (DCT-SE), is presented to r...

In this paper we propose using the correlated cosine structure (CCS) for the computation of the discrete cosine transform (DCT). This structure has circulant property and is most suitable for the hardware realization. We will show that there exists a close relationship between the CCS and the DCT. In such a case, a 2"' length DCT can be decomposed recursively into shorter length CCS and DCT. Th...

In this paper, we present a discuccion on DCT a l g o r i h based on convolutions. It is shown that these approaches can provide effective solutionr to realize DCTS Besides, thqt provide a theoretical lower bound on the number of multiplications required for the realization of DCTs Some fa* shon length DCT alprithms have ah0 been dm'ved f i m thcw approaches.

We propose a new method of “space coding” to transmit the 3-D space as it is. A multi-dimensional DCT is applied to the 4-D data space in which the ray data is filled densely. Experimental results show the relation between the resolution of 4-D data space and the coding performance. 1 はじめに 最近、3次元画像通信や VRに関する研究が注目され つつある。筆者らは、様々な 3次元画像入出力方式を統 一的に取り扱うために、3次元統合画像通信の構想を提 案し [1]、3次元空間の記述方式として、空間を伝搬す...

Currently existing subpixel motion estimation algorithms require interpolation of inter-pixel values. However, it is shown in this paper that, by introducing the concept of pseudo phase shifts in DCT coeecients of a moving object's intensity, subpixel displacements can be estimated on two consecutive frames in DCT domain without interpolating inter-pixel values. Speciically, under a certain con...

A three-dimensional DCT (3D-DCT) block-based video compression (3D-DCT VC) could be a promising solution for limited memory, processing power and energy consumption computation platforms. Providing reduced computation complexity and being free from error-drift problem, it, however, suffers from a “blockiness” of decoded video due to the coarse quantization of transform coefficients, in the same...

I n this paper, we propose efficient techniques and architectures for realizing spatial-downscaling transcoders in the DCT domain. We also present methods for re-sampling motion vectors and determining coding modes. We propose a novel drift-free architecture which simplifies the cascaded DCT-domain downscaling transcoder (CDDT) by integrating the downscaling process into the DCT-domain motion c...