This work presents an image denoising algorithm, arguably the simplest among all the counterparts, but surprisingly effective. The algorithm exploits the image pixel correlation in the spacial dimension as well as in the color dimension. The color channels of an image are first decorrelated with a 3point orthogonal transform. Each decorrelated channel is then denoised separately via local DCT (...

Discrete cosine transform (DCT) plays an important role in video coding. Integer DCTs which approximate the standard DCT– II have been developed for various sizes i.e., N = 4, 8, 16, etc. In this paper, a review of various integer DCTs used in H.264, AVSchina and VC-1 is provided. For a first order Markov process, with high adjacent correlation coefficient, ρ = 0.95 and N=8 properties like tran...

This paper proposes an energy-efficient hardware acceleration architecture for the variable N-point 1D Discrete Cosine Transform (DCT) that can be leveraged if implementing MPEG-4’s Shape Adaptive DCT (SA-DCT) tool. The SA-DCT algorithm was originally formulated in response to the MPEG-4 requirement for object based texture coding, and is one of the most computationally demanding blocks in an M...

The 4×4 approximate discrete cosine transform (DCT) of H.264/AVC [1] makes it difficult to transcode the pre-coded video contents with the previous video coding standards to H.264/AVC in DCT domain. This is due to the difference between 8×8 DCT used previous standards and 4×4 DCT in H.264/AVC. In this paper, we propose an efficient algorithm that converts the quantized 8×8 DCT block of MPEG-2 i...

In this paper, contrast enhancement of dark image using Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) coefficients is proposed. Then the contrast enhancement is obtained by applying Dynamic Stochastic Resonance (DSR).The goal of dark image enhancement is to clearly visualize the features of the image. Two different coefficients DCTand DWT are used for implementing contras...

The contrast enhancement technique used manipulates the DCT coefficients of a JPEG image to improve its quality. It is carried out in the decompression stage so that the compressibility of the image is not affected. Since DCT and its inverse transform IDCT are performed on 8 x 8 blocks of pixels, any image processing algorithm implemented in the transform domain produces flaws known as blocking...

Image retrieval is an important problem for accessing large image databases. In this paper, a content-based image retrieval method based on block DCT is proposed. Due to the energy compacting property and the ability of extracting the texture information, discrete cosine transform (DCT) is applied to extract low-level features from the images. Based on the observation that block DCT can reduce ...

Although most of the proposals for implementing motion-compensated temporal filtering (MCTF) schemes are based on the wavelet transform, in this paper, we propose an MCTF framework based on the discrete cosine transform (DCT). Using DCT decimation and interpolation, several temporal decomposition structures named motion-compensated DCT temporal filters (MCDCT-TF) are introduced. These structure...

In this paper a reversible discrete cosine transform (RDCT) is presented. N-point reversible transform is firstly presented, then 8-point RDCT is obtained by substituting the 2 and 4point reversible transforms for 2 and 4-point transforms which compose 8-point discrete cosine transform (DCT), respectively. Integer input signal can be losslessly recovered, although the transform coefficients are...

In most low-power VLSI designs, the supply voltage is usually reduced to lower the total power consumption. However, the device speed will be degraded as the supply voltage goes down. In this paper, we propose new algorithmic-level techniques to compensate the increased delays based on the multirate approach. We apply the technique of polyphase decomposition to design low-power transform coding...