Set Partitioning In Hierarchical Trees Encoder Research Articles

Blind Dual Watermarking Scheme Using Stucki Kernel and SPIHT for Image Self-Recovery

In this paper we propose a blind dual watermarking scheme using Set Partitioning in Hierarchical Trees (SPIHT) and Stucki Kernel halftone technique for the tamper detection and image self-recovery. The watermark consists of authentication bits for tampering area location and recovery bits for image restoration. We generate two recovery bits to ensure the high-quality recovery of the tampered image. The primary recovery bit is generated by the SPIHT encoding, and the secondary recovery bit is generated by the Stucki Kernel halftone technique. Then the authentication bit is generated based on the recovery bits. Before embedding the watermark, we shuffle the watermark bits through Arnold cat mapping and diagonal mapping to improve the security and quality of the restored image. LSB-based watermarking technique is used to embed the watermark into the original image to ensure the invisibility of the watermarked image. Experiments have been conducted on two datasets, BOW2 and USC-SIPI, and results show that the proposed scheme can achieve high restoration quality. Comparison with the existing works demonstrate the good performance and superiority of the proposed scheme.

Medical Video Coding Based on 2nd-Generation Wavelets: Performance Evaluation

The operations of digitization, transmission and storage of medical data, particularly images, require increasingly effective encoding methods not only in terms of compression ratio and flow of information but also in terms of visual quality. At first, there was DCT (discrete cosine transform) then DWT (discrete wavelet transform) and their associated standards in terms of coding and image compression. The 2nd-generation wavelets seeks to be positioned and confronted by the image and video coding methods currently used. It is in this context that we suggest a method combining bandelets and the SPIHT (set partitioning in hierarchical trees) algorithm. There are two main reasons for our approach: the first lies in the nature of the bandelet transform to take advantage of capturing the geometrical complexity of the image structure. The second reason is the suitability of encoding the bandelet coefficients by the SPIHT encoder. Quality measurements indicate that in some cases (for low bit rates) the performance of the proposed coding competes with the well-established ones (H.264 or MPEG4 AVC and H.265 or MPEG4 HEVC) and opens up new application prospects in the field of medical imaging.

Medical Image Compression in WBCT Domain Using Fast FIC and SPIHT Coding

Fractal image coding encodes the input image with low bit rate and decodes the same with the reasonable quality of reconstruction. But, FIC has the demerit of longer time taken for encoding. In this paper, a fractal and SPIHT encoding of WBCT coefficients is proposed. Fast fractal encoding using particle swarm optimization (PSO) is applied to the low pass sub band of wavelet based contourlet transformed image and a modified set partitioning in hierarchical trees (SPIHT) coding is applied on the remaining coefficients. PSO technique and reduced domain pool size will speed up the fractal encoder, whereas the WBCT coefficients preserve the image quality in case of smooth contoured images. Furthermore, image details and wavelet progressive transmission characteristics are maintained. Experimental results prove that the proposed algorithm provides better quality of reconstruction with reduced bit rate.

Improved Techniques for Mammographie Image Compression using Balanced Multiwavelet Block Tree Coding

The recent innovation in digital medical imaging techniques requires the development of high-performance storage and image transmission systems. The biggest problem in digital technology is voluminous amount of data generated. For example, a digital mammographic image of size 1024 × 1024 pixels with 8 bits per pixel requires 8.3 Mb for storing it in original form. Researchers in several studies have demonstrated the need for high rate compression algorithms for medical imaging applications. But the recently reported image compression results indicate that Peak Signal-to-Noise Ratio (PSNR) is outperformed by scalar wavelets. However, it often fails to capture high-frequency information accurately. Interestingly, multiwavelet preserves high-frequency information in mammographic image and provides good energy compaction. The challenge still remains as to how one can better represent the signal for achieving the best compression. This paper proposes a solution to the above open problems using balanced multiwavelet-based image compression. The proposed scheme presents combination of two novel ideas: A coefficient reorganization suitable to balanced multiwavelet decomposition is used to regain the parent-child relationship. A block tree coding is used for compression and reconstruction of multiwavelet transformed image and thus the proposed scheme is called as Multiwavelet Block Tree Coding (MBTC). This approach yields the advantages of high energy compaction, PSNR, and a less number of bits for encoding. Balanced multiwavelet-based compression, with MBTC applied to a set of four mammographic images, achieves an average PSNR of 43.245 dB against the existing Set Partitioning In Hierarchical Trees (SPIHT) algorithm which on an average achieves only 34.181 dB for 0.5 bpp bit rate and MBTC requires encoding bits of 45.565% less than SPIHT encoding.

Delta-MFCC Features and Information Theoretic Expectation Maximization based Text-independent Speaker Verification System

The recent innovation in digital medical imaging techniques requires the development of high-performance storage and image transmission systems. The biggest problem in digital technology is voluminous amount of data generated. For example, a digital mammographic image of size 1024 × 1024 pixels with 8 bits per pixel requires 8.3 Mb for storing it in original form. Researchers in several studies have demonstrated the need for high rate compression algorithms for medical imaging applications. But the recently reported image compression results indicate that Peak Signal-to-Noise Ratio (PSNR) is outperformed by scalar wavelets. However, it often fails to capture high-frequency information accurately. Interestingly, multiwavelet preserves high-frequency information in mammographic image and provides good energy compaction. The challenge still remains as to how one can better represent the signal for achieving the best compression. This paper proposes a solution to the above open problems using balanced multiwavelet-based image compression. The proposed scheme presents combination of two novel ideas: A coefficient reorganization suitable to balanced multiwavelet decomposition is used to regain the parent-child relationship. A block tree coding is used for compression and reconstruction of multiwavelet transformed image and thus the proposed scheme is called as Multiwavelet Block Tree Coding (MBTC). This approach yields the advantages of high energy compaction, PSNR, and a less number of bits for encoding. Balanced multiwavelet-based compression, with MBTC applied to a set of four mammographic images, achieves an average PSNR of 43.245 dB against the existing Set Partitioning In Hierarchical Trees (SPIHT) algorithm which on an average achieves only 34.181 dB for 0.5 bpp bit rate and MBTC requires encoding bits of 45.565% less than SPIHT encoding.

Performance improvement of the SPIHT coder

The set partitioning in hierarchical trees (SPIHT) coder is one of the state-of-the-art coders among the wavelet-based image compression coders. For improving the performance of the SPIHT coder, in this paper, we propose a pre-processing method that applies the discrete sine transform or the discrete cosine transform to the wavelet coefficients in the highest frequency subbands and in the next highest frequency subbands before the SPIHT encoding. Experimental results show that the proposed method increases the peak signal to noise ratio by up to 0.4 (dB) in textured images over the original SPIHT coder.

Significance map pruning and other enhancements to SPIHT image coding algorithm

This paper proposes several enhancements to the Set Partitioning in Hierarchical Trees (SPIHT) image coding algorithm without changing the original algorithm's general skeleton. First and foremost, a method for significance map pruning based on a rate-distortion criterion is introduced. Specifically, the (Type A) sets of wavelet coefficients with small ratios of estimated distortion reduction to estimated rate contribution are deemed insignificant and effectively pruned. Even though determining such sets requires the computational complexity of the encoder to increase considerably with respect to the original SPIHT encoder, the original SPIHT decoder may still be used to decode the generated bitstream with a low computational complexity. The paper also proposes three low complexity enhancements by more sophisticated use of the adaptive arithmetic coder. Simulation results demonstrate that all these enhancements yield modest compression gains at moderate to high rates.

Reduced bit rate uniform quantisation for SPIHT encoding

Set partitioning in hierarchical trees (SPIHT) is a scalar quantiser for images that have undergone subband decomposition by wavelet transform. Reduced bit rates have been achieved by merging the first and second passes of the already efficient SPIHT algorithm. The modification requires neither entropy encoding nor significant increase to the algorithmic complexity.