Digital watermarking has been presented as a new method for copyright protection. This technique embeds a secret signal in a digital image or video sequence that allows one to establish ownership or identify a buyer. ...
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Digital watermarking has been presented as a new method for copyright protection. This technique embeds a secret signal in a digital image or video sequence that allows one to establish ownership or identify a buyer. The common digital image watermarking techniques are spatial or transform-based, which are based on spread-spectrum communications. Most of transform-domain watermarking methods are based on discrete cosine transforms (DCT) and robust to JPEG lossy compression. Recently, digital image watermarking based on another important lossy compression technique, vector quantization (VQ), has been presented, which carries watermark information by codeword indices. It is secret and efficient, and is robust to VQ compression with the same codebook. block truncation coding (BTC) is a fast lossy image coding technique suitable for real-time image transmission. Both VQ and BTC have some shortcomings that affect their applications to image compression. To reduce edge degradation produced by VQ and BTC, VQ-BTC has been presented as an efficient technique for low-bit-rate image encoding. This paper presents a more efficient image watermarking method based on VQ-BTC. Experimental results show that the proposed technique is efficient and secret.
A considerable amount of calligraphy has been accumulated from past Chinese dynasties. With the arrival of the digital era, this calligraphy is being digitalized. However, when digital representations of the calligrap...
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A considerable amount of calligraphy has been accumulated from past Chinese dynasties. With the arrival of the digital era, this calligraphy is being digitalized. However, when digital representations of the calligraphy are transmitted over a noisy channel, transmission errors usually occur. In this paper, we propose a new error prevention and concealment method for Chinese calligraphy. The basic idea of the method is to extract the image feature from a Chinese calligraphy and use it as the auxiliary information. Next, the auxiliary information is embedded into the BTC-compressed codes of the original image. Therefore, the auxiliary information can be extracted to help with the reconstruction of the errant blocks during the error concealment phase. From our experimental results, the proposed scheme can effectively conceal the errant blocks. Moreover, when comparing our method with related research, the image quality of our proposed method is superior to those of PIR and GSBEC. The superiority is more outstanding when the errant blocks are larger. Therefore, our proposed method is a highly effective error concealment technique for Chinese calligraphy.
Ordered dither block truncation coding (ODBTC) employs the ordered dither technique to produce the bitmap required in traditional block truncation coding (BTC). It can reduce the complexity of computations in the codi...
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Ordered dither block truncation coding (ODBTC) employs the ordered dither technique to produce the bitmap required in traditional block truncation coding (BTC). It can reduce the complexity of computations in the coding phrase. However, the blocking artifacts and undesired noises are still in the decoded images by ODBTC. In this paper, the properties of thresholds stored in the dither matrices are considered to estimate the decoded pixel intensities. That is, the dither matrices are used in both coding and decoding. Experimental results tell that the proposed schema can not only reduce quantization error but also improve the visual quality for the reconstructed images by ODBTC.
A novel progressive image transmission scheme that is capable of achieving good reconstructed image quality at a low computational cost is proposed. The quadtree segmentation technique is employed to exploit the spati...
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A novel progressive image transmission scheme that is capable of achieving good reconstructed image quality at a low computational cost is proposed. The quadtree segmentation technique is employed to exploit the spatial similarity among neighbouring pixels. Besides, the mean values and the absolute moment block truncation coding with bit plane omission are used to encode smooth blocks and complex blocks respectively. By choosing suitable controlling thresholds in the quadtree segmentation technique, multiple stages of reconstructed images can be obtained at low bit rates.
block truncation coding (BTC) technique is a simple and fast image compression algorithm since complicated transforms are not used. The principle used in BTC algorithm is to use two‐level quantiser that adapts to loc...
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block truncation coding (BTC) technique is a simple and fast image compression algorithm since complicated transforms are not used. The principle used in BTC algorithm is to use two‐level quantiser that adapts to local properties of the image while preserving the first‐ or first‐ and second‐order statistical moments. The parameters transmitter or stored in the BTC algorithm are statistical moments and bitplane yielding good quality images at a bitrate of 2 bits per pixel (bpp). In this paper, two algorithms for modified BTC (MBTC) are proposed for reducing the bitrate below 2 bpp. The principal used in the proposed algorithms is to use the ratio of moments which is a smaller value when compared to absolute moments. The ratio values are then entropy coded. The bitplane is also coded to remove the correlation among the bits. The proposed algorithms are compared with MBTC and the algorithms obtained by combining JPEG standard with MBTC in terms of bitrate, peak signal‐to‐noise ratio (PSNR) and subjective quality. It is found that the reconstructed images obtained using the proposed algorithms yield better results.
In this letter. a new scheme of designing multilevel BTC coding is proposed. The optimal quantization can obtain by selecting the quantization threshold with an exhaustive search. However, it requires an enormous amou...
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In this letter. a new scheme of designing multilevel BTC coding is proposed. The optimal quantization can obtain by selecting the quantization threshold with an exhaustive search. However, it requires an enormous amount of computation and is thus impractical while we take an exhaustive search for the multilevel BTC. A two-steps searching method is applied to reduce the computational complexity. Comparisons of results with various methods have verified that the proposed method approach to the optimal quantization with little computation complexity.
In this paper, we propose a hybrid feature which merges block truncation coding (BTC) and Tree-Structured Vector Quantization (TSVQ) with classification of edge orientation bit-planes. BTC is known for its high qualit...
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In this paper, we propose a hybrid feature which merges block truncation coding (BTC) and Tree-Structured Vector Quantization (TSVQ) with classification of edge orientation bit-planes. BTC is known for its high quality of reconstructed images, much lower computational complexity and low compression ratios. Vector Quantization (VQ), on the other hand, results in very high compression ratios but with high complexity. To solve these problems, we propose an improved approach for feature extraction based on bit-plane classification according to the Edge Orientation of the Bit-Plane (EOBP) templates and combine it with TSVQ. As different areas of the image have different activities and contrasts, we encode the active blocks containing edges with BTC and EOBP templates, and encode the inactive blocks having low intensity variations between its pixels with the VQ. Different from the original BTC and VQ based feature extraction, we extract the edge orientation information by applying the EOBP classification on the bit-plane image blocks, as a result that we classify image blocks into 28 kinds with different edges. Simulation results show that our proposed method performs better in image compression and image retrieval.
Image watermarking is one of the most accepted solutions protecting image authenticity. The method presented in this paper not only provides the desired outcome also efficient in terms of memory requirements and prese...
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Image watermarking is one of the most accepted solutions protecting image authenticity. The method presented in this paper not only provides the desired outcome also efficient in terms of memory requirements and preserving image characteristics. This scheme effectively utilizes the concepts of block truncation coding (BTC) and lifting wavelet transform (LWT). The BTC method is applied to observe the binary watermark image corresponding to its gray-scale image. Whereas, the LWT is incorporated to transform the cover image from spatial coordinates to corresponding transform coordinates. In this, a quantization-based approach for watermark bit embedding is applied. And, the extraction of binary watermark data from the attacked watermarked image is based on adaptive thresholding. To show the effectiveness of the proposed scheme, the experiment over different benchmark images is performed. The experimental results and the comparison with state-of-the-art schemes depict not only the good imperceptibility but also high robustness against various attacks.
In this paper,a hybrid block truncation coding (HBTC) is presented for color image *** the HBTC algorithm to improve the compression ratio of the basic BTC,only luminance bit-map is employed to represent the edge info...
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In this paper,a hybrid block truncation coding (HBTC) is presented for color image *** the HBTC algorithm to improve the compression ratio of the basic BTC,only luminance bit-map is employed to represent the edge information of the coding ***,an efficient previous proposed algorithm,adaptive quantization coding (AQC),is used to compress the two representative levels *** results show that the proposed HBTC performs as well as the BTC in terms of subject visual quality,and significantly improves the compression ratio of BTC from 2.88:1 to 6.00:1 with the limited performance losing about 0.66dB in PSNR.
In this paper, we have CBIR, which is known as Content based Image Retrieval is the application of computer vision technique to the image retrieval problem from the large databases. In this paper de-duplication of ele...
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ISBN:
(纸本)9781479984343
In this paper, we have CBIR, which is known as Content based Image Retrieval is the application of computer vision technique to the image retrieval problem from the large databases. In this paper de-duplication of electricity bills is done through CBIR. The technique for comparing the images is block truncation coding;it is a lossy compression technique for grayscale image. So Photograph of electricity was divided into different block size using a compression technique known as block truncation coding. On the basis of block size, we will put images of the same block size in the same cluster. As there will be large block, so they will be divided into chunks of data. Through this experiment we will try to remove duplicates in the same cluster. In this paper the block of data is also divided into different chunks, so that image of single instance can be stored in these chunks. So duplication will be improved with the help of compression techniques discussed in detail.
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