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Color features are important to pictures and they are easy to calculate. Therefore, the features are widely used in content-based image retrieval (CBIR). A color histogram describes the frequency of colors in images. It won't change with the variations of pictures' geometry, so it is a widely used feature for image indexing although it has some shortcomings. In this paper, we propose a new color space...
Block-based DCT compression methods usually result in discontinuities called blocking artifacts at the boundaries of blocks due to the coarse quantization of the coefficients. In order to save more computations, an algorithm directly based on DCT-domain is proposed. It reduces the blocking artifacts as much as possible and preserve edge adequately as well. The algorithm presents a specific and convenient...
This paper presents an image content authentication algorithm resilient to geometric and some general operations. The original image is normalized into a standard prototype form according to the blind normalization arithmetic, and then the smooth-component and the edge-character are drawn from the prototype image with the dyadic wavelet transform multi-scale edge detection. After coded with 64 bits,...
An image scrambling algorithm based chaos and wavelet transform is proposed in this paper. Scrambling is performed in wavelet domain in order to resist statistical analysis attack. Due to the advantages of the confusion and diffusion characteristics of the two-dimensional chaotic sequences, the algorithm obtains good scrambling effect and security. Experiments show that the algorithm can endure commonly...
Character extraction is a very important task in document image process and recognition. It's also a main step in our image compression scheme for flight coupon images storage. In this paper we improve a segmentation method based on hierarchical layout analysis to extract variable printed characters. Experimental results show the performance of the proposed algorithm
When a high compression ratio is required, the block discrete cosine transform (BDCT) decoded image suffers from the blocking effect: boundaries between adjacent image blocks visible for low bit rates. A blocking effect reduction algorithm based on DCT transform and Markov random field (MRF) is proposed to reduce blocking artifacts as many as possible, while preserving edge information. In this paper,...
A controllable decoding or progressive decoding is an elegant feature for some multimedia applications. In this paper, we present a new fractal image decoding method for fractal image compression based on an extended fixed-point iteration theorem. The experimental results show that controlling the fractal decoding process with different non-decreasing sequences is more effective and flexible than...
This paper presents a chaos-based watermarking algorithm in the wavelet transform domain for color images. In contrast to conventional approaches, in which the wavelet transform coefficient is used for watermarking and the whole image is transformed into frequency coefficient, the wavelet transform is applied only to local subblock. DWT is used to transform the subimage, which is extracted from the...
The region of interest (ROI) coding is an important application of region-based still image coding and can encode these significant regions with higher quality than others (background). In this paper, we present a new region-based image coding method called partial subbands maximum bitplanes shift (PSMBShift). The new method applies different scaling strategies for the different frequency subbands...
This paper presented a high speed multiple word parallel architecture (MWPA) with sequential coding for fractional bit plane coding used in JPEG 2000, where all bit planes are coded in parallel, and all bit samples in the same bit plane are coded in sequential. The proposed MWPA adopts a technique of performing the coding pass prediction and context formation in parallel and pipelined fashion, thus...
This paper purposes a novel matching algorithm for image encoding using adaptive classification scheme (ACS) in fractal image compression. It processes based on standard deviation (STD) between range blocks and domain blocks. In this paper, there are two main works, i) the threshold is set to be the ratio of the STD difference and made adaptive ii) we enhance Tong's STD search algorithm by introducing...
A palmprint image contains abundant features, such as the ridges, lines and textures, etc. Different features reflect the different characteristic of the palmprint. Fusion of multiple palmprint features may enhance the performance of a palmprint authentication system. In this paper, we investigate the fusion of two novel palmprint representations: orientationCode and diffCode. OrientationCode are...
In this paper, the method of 2DPCA is analyzed and its nature is revealed, i.e., 2DPCA is equivalent to view rows of face images as training samples that constitute row training sets and then use PCA for feature extraction. We also have proved that principal component vectors extracted by 2DPCA contain redundancy in theory. Based on this result, this paper presents a new image feature extraction method...
An image encryption scheme based on chaotic systems is proposed in this paper. By combining the spatial-domain encryption of digital images and the traditional stream ciphers technology, the security of the encryption scheme is enhanced effectively. Instead of encrypting an image in a chaotic signal directly, the proposed scheme uses two chaotic systems based on the thought of higher secrecy of multi-system...
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