Three novel image compression schemes are proposed here for multimedia applications. The schemes are designed to combine the advantages of vector quantization and block truncation coding based on quadtree segmentation...
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Three novel image compression schemes are proposed here for multimedia applications. The schemes are designed to combine the advantages of vector quantization and block truncation coding based on quadtree segmentation. A new Vector quantization scheme, calf ed subsampling VQ (SVQ), is proposed and used in the new schemes. The spatial correlation between neighboring image blocks and uniformity in variable-sized image blocks is exploited in these schemes. Simulation results show that the new schemes have succeeded in achieving better coding performance with subjective image quality at low bit rates. (C) 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)021 02-4].
An image watermarking model based on visual secret sharing (VSS) is proposed for protection of ownership. In the embedding phase, the watermark is first divided by VSS into two parts: a hiding watermark and a secret w...
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An image watermarking model based on visual secret sharing (VSS) is proposed for protection of ownership. In the embedding phase, the watermark is first divided by VSS into two parts: a hiding watermark and a secret watermark. Then only the hiding watermark is embedded into the original image and the secret watermark is reserved for watermark extracting by the owner. In the extracting phase, the hiding watermark is extracted from the watermarked image first and then directly superimposed on the secret watermark to recover the watermark information.
block truncation coding (BTC) is a successful image compression technique due to its simple and fast computational burden. The bit rate is fixed to 2.0 bits/pixel, whose performance is moderate in terms of compression...
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block truncation coding (BTC) is a successful image compression technique due to its simple and fast computational burden. The bit rate is fixed to 2.0 bits/pixel, whose performance is moderate in terms of compression ratio compared to other compression schemes such as discrete cosine transform (DCT), vector quantization (VQ), wavelet transform coding (WTC), etc. Two kinds of overheads are required for BTC coding: bit plane and quantization values, respectively. A new technique is presented to reduce the bit plane overhead. Conventional bit plane overhead is 1.0 bits/pixel;we decrease it to 0.734 bits/pixel while maintaining the same decoded quality as absolute moment BTC (AMBTC) does for the "Lena" image. Compared to other published bit plane coding strategies, the proposed method outperforms all of the existing methods. (C) 2002 Society of Photo-Optical Instrumentation Engineers.
block truncation coding is one of the oldest known forms of image compression algorithms, its main attraction being its simple underlying concepts and ease of implementation. In this paper we present a new Predictive ...
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ISBN:
(纸本)0819437034
block truncation coding is one of the oldest known forms of image compression algorithms, its main attraction being its simple underlying concepts and ease of implementation. In this paper we present a new Predictive Absolute Moment block truncation coding scheme which improves the performance of the existing block truncation coding schemes. The proposed scheme is based on selectively predicting the reconstruct-ion values of a block based on the corresponding values in the neighbouring blocks, as well as predicting the bitplane from the bitplanes of the corresponding blocks in other colour components.
Vector quantization (VQ) and block truncation coding (BTC) are two popular schemes for image compression. VQ has been widely used for its simplicity and low bit rate;on the other hand, BTC has the advantages of requir...
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Vector quantization (VQ) and block truncation coding (BTC) are two popular schemes for image compression. VQ has been widely used for its simplicity and low bit rate;on the other hand, BTC has the advantages of requiring little computational cost and providing high image quality. To put together the advantages of VQ and ETC, three hybrid methods based on VQ and ETC are proposed in this paper. According to our experimental results, it is shown that the first two methods of ours produce good image quality while keeping low bit rate. Meanwhile, the third method produces higher image quality while keeping acceptable bit rate. Also, these methods require little computational cost. In other words, our methods can be applied to diverse occasions according to their specific requirements. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)00204-4].
In this paper, a new scheme for designing multilevel ETC coding is proposed. Optimal quantization can be obtained by selecting the quantization threshold with an exhaustive search. However, this requires an enormous a...
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In this paper, a new scheme for designing multilevel ETC coding is proposed. Optimal quantization can be obtained by selecting the quantization threshold with an exhaustive search. However, this requires an enormous amount of computation and is, thus impractical when we consider an exhaustive search for the multilevel ETC. In order to find a better threshold so that the average mean square error between the original and reconstructed images is a minimum, the genetic algorithm is applied. Comparison of the results of the proposed method with the exhaustive search reveal that the former method can almost achieve optimal quantization with much less computation than that required in the latter case.
block truncation coding uses a two-level moment preserving quantizer that adapts to local properties of the images. It has the features of low computation load and low memory requirement while its bit rate is only 2.0...
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block truncation coding uses a two-level moment preserving quantizer that adapts to local properties of the images. It has the features of low computation load and low memory requirement while its bit rate is only 2.0 bits per pixel. A more efficient algorithm, the absolute moment ETC (AMBTC) has been extensively used in the field of signal compression because of its simple;computation and better MSE performance. We propose postprocessing methods to further reduce the entropy of two output data of AMBTC, including the bit map and two quantization data (a, b). A block of a 2x4 bit map is packaged into a byte-oriented symbol. The entropy can be reduced from 0.965 bpp to 0.917 bpp on average for our test images. The two subimages of quantization data (a, b) are postprocessed by the Peano Scan. This postprocess can further reduce differential entropy about 0.4 bit for a 4x4 block. By applying arithmetic coding, the total bit reduction is about 0.3 similar to 0.4 bpp. The bit rate can reach 1.6 similar to 1.7 bpp with the same quality as traditional AMBTC.
This paper presents a modified block truncation coding (ETC) algorithm for image compression. Similar blocks in an image are merged into a cluster and represented with the cluster center. Each cluster center is then e...
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This paper presents a modified block truncation coding (ETC) algorithm for image compression. Similar blocks in an image are merged into a cluster and represented with the cluster center. Each cluster center is then encoded with a vision block truncation coding (VBTC) algorithm which uses a small set of predefined binary edge patterns to approximate the bit plane of the cluster center. Experimental results show that the computation efficiency of the proposed algorithm is significantly improved when compared to the original BTC. (C) 1998 Elsevier Science B.V. All rights reserved.
The paper proposes a pipelined architecture of visual block pattern truncationcoding algorithm to minimize mean square error. Using this chip, the VBPTC based system can be applied to real-time encoding for the movin...
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The paper proposes a pipelined architecture of visual block pattern truncationcoding algorithm to minimize mean square error. Using this chip, the VBPTC based system can be applied to real-time encoding for the moving pictures.
block truncation coding (BTC) is an efficient blockcoding technique suitable for real-time image compression, and it has high channel error resisting capability and good reconstructed image quality. Absolute moment E...
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block truncation coding (BTC) is an efficient blockcoding technique suitable for real-time image compression, and it has high channel error resisting capability and good reconstructed image quality. Absolute moment ETC (AMBTC) is a simple and fast variant of ETC, The main shortcoming of the original AMBTC algorithm is the high bit rate (normally 2bits/pixel). In order to reduce the bit rate of AMBTC, an efficient ETC image compression algorithm with vector quantization (VQ) is presented in this paper. The main idea of the proposed algorithm is to reduce the number of bits required to code the higher mean, the lower mean and the bit plane, which are created by AMBTC for each image block. On the one hand, a simple look-up-table method is presented for coding the higher mean and the lower mean of a block. On the other hand, vector quantization technique is introduced to reduce the number of bits used to code the bit plane. Test results prove the effectiveness of the proposed algorithm.
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