Papers by Keyword: DCT

Abstract: As an improvement of Cheng etal.’s print-and-scan (PS) digital watermarking scheme, the proposed method solves the data extraction failure problem caused by pixel displacement. We propose to embed the watermark into the middle band of DCT coefficients based on the fact that the mean of DCT coefficients (MDC) is zero before and after PS. Besides, a mapping method is designed which can distribute the change of average to the original image pixels according to the local complexity. Meanwhile, we use the JND model mentioned in Cheng et al.’s scheme to guarantee the visual quality. Extensive experiments show that the proposed scheme is effective to resist PS, and the performance of the proposed scheme is better than that of Cheng et al.’s scheme.

Abstract: In this paper, the advantage of hybrid electric vehicle (HEV) equipped with dual clutch transmission (DCT) was presented. Five HEV simulation models equipped with DCT were built on the basis of AVL CRUISE software. According to different power-train configurations, different control strategies were built by MATLAB/SIMULINK. The advantage and disadvantage of each power-train configurations was analyzed through simulation. The results supplied the foundation for the next step vehicle development.

Abstract: The long term evolution (LTE) system is a high data rate transmission system. And the channel estimation is critical to it. In this paper, a novel channel estimator on the basis of Discrete Cosine Transform (DCT) method is presented for LTE. It can mitigate the aliasing error caused by spectral leakage well and is applicable for non-integer sampled channel because DCT can reduce the high frequency component. Its performance is much better than LS method and close to LMMSE method, and the complexity is much simpler than LMMSE. The simulation results show that the DCT-based method is superior to the traditional channel estimation algorithm in the multi-path Rayleigh fading channel which is a available and effective channel estimation method.

Abstract: Traditional fast algorithms for DCT are aimed at sequences with 2^N length and it is math-intensive for sequences which contain odd numbers of elements. This paper analyzes the redundant calculation of cosine transform of non-2^N-point sequences and put forward a fast algorithm for one-dimensional DCT with odd length. Also, according to the separability of two-dimensional DCT, we can generalize the fast algorithm for one-dimensional DCT to two-dimensional DCT to implement and complete the fast algorithm. The simulation suggests that this algorithm improves the speed of calculation.

Abstract: Discrete Cosine Transform (DCT) is commonly used in image compression. In the history of DCT, a milestone was the Distributed Arithmetic (DA) technique. Due to the technology dependency a multiplier-less computation was built with DA based technique. It occupied less area but the throughput is less. Later, due to the technology scaling, multiplier based architectures can be easily adapted for low-power and high-performance architecture. Fixed width multipliers [1]-[7] reduces hardware and time complexity. In this work, Radix 4 fixed width multiplier is adapted with DCT architecture due to low power consumption and saves 30% power. In order to reduce truncation errors caused during fixed width multiplication, an estimation circuit is designed based on conditional probability theory.

Abstract: Medical imaging is important in trendy medical aid that gives diagnostic info for clinical management of patients and designing of treatment. Every year, terabytes of medical image data’s square measure used through advanced imaging modalities like Positron Emission Tomography (PET) Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and lots of additional new methodology of medical imaging. Advances in technology have created the chance for radiology systems to use complicated compression algorithms to scale back the file size of every image in an attempt to partly offset the rise in knowledge volume created by new or additional complicated modalities whereas protective the numerous diagnostic info. This paper outlines the various compression strategies like Discrete Cosine Transform (DCT), Fractal Compression and Set Partitioning In hierarchical Trees (SPIHT) applied to numerous medical pictures. Experimental results show that the projected SPIHT approach achieves the next Compression Ratio (CR), Bits Per Pixel (BPP) and Peak Signal to Noise Ratio (PSNR) with less Mean square Error (MSE) in comparison with DCT methodology.

Abstract: This paper proposes a unified architecture for computation of discrete cosine transform (DCT) and its inverse transform (IDCT). The matrix decomposition algorithm is used to deduce the proposed algorithm. Based on this algorithm, a unified DCT/IDCT architecture is developed. Then, this architecture is modeled in HDL, verified and implemented with FPGA. Experiment results show that the unified DCT/IDCT architecture has low hardware complexity and high calculation accuracy.

Abstract: In this paper, A new algorithm for compressed image retrieval is proposed based on Gaussian Density Feature Vector(GDFV). This algorithm directly extract gaussian density of 8 direction from compressed image data to construct a 2-dimention array (8*4) as an indexing key to retrieve images based on their content features. To test and evaluate the proposed algorithms, we carried out experiments with a database of 1000 images. In comparison with existing representative techniques, the experimental results show the superiority of the proposed method in terms of retrieval precision and processing speed.

Abstract: Image watermarking is a carrier image watermarking technology. This paper studies the research direction of the digital watermarking image of the DCT-based image robust watermarking algorithm design. We studies robust algorithm of watermarking image on specific design and implementation process based on DCT domain, the process including image watermarking embedding and watermarking extraction and watermarking detection. Experimental results achieved watermarking embedding evaluation requirements: effectiveness, transparency and robustness.

Abstract: A progressive transmission and decoding nearly lossless compression algorithm is proposed. The image data are grouped according to different frequencies based on DCT transform, then it uses the JPEG-LS core algorithmtexture prediction and Golomb coding on each group of data, in order to achieve progressive image transmission and decoding. Experimentation on the standard test images with this algorithm and comparing with JPEG-LS shows that the compression ratio of this algorithm is very similar to the compression ratio of JPEG-LS, and this algorithm loses a little image information but it has the ability of the progressive transmission and decoding.