Wavelet Based Image Coding Schemes : A Recent Survey

A variety of new and powerful algorithms have been developed for image compression over the years. Among them the wavelet-based image compression schemes have gained much popularity due to their overlapping nature which reduces the blocking artifacts that are common phenomena in JPEG compression and multiresolution character which leads to superior energy compaction with high quality reconstructed images. This paper provides a detailed survey on some of the popular wavelet coding techniques such as the Embedded Zerotree Wavelet (EZW) coding, Set Partitioning in Hierarchical Tree (SPIHT) coding, the Set Partitioned Embedded Block (SPECK) Coder, and the Embedded Block Coding with Optimized Truncation (EBCOT) algorithm. Other wavelet-based coding techniques like the Wavelet Difference Reduction (WDR) and the Adaptive Scanned Wavelet Difference Reduction (ASWDR) algorithms, the Space Frequency Quantization (SFQ) algorithm, the Embedded Predictive Wavelet Image Coder (EPWIC), Compression with Reversible Embedded Wavelet (CREW), the Stack-Run (SR) coding and the recent Geometric Wavelet (GW) coding are also discussed. Based on the review, recommendations and discussions are presented for algorithm development and implementation.Comment: 18 pages, 7 figures, journa

A NOVEL ALGORITHM FOR COLOR VISUAL CRYPTOGRAPHIC IMAGES USING ERROR FILTERING SCHEMES IJCET © I A E M E

ABSTRACT This paper proposes an efficient color image visual cryptic filtering scheme to improve the image quality on restored original image from visual cryptic shares. The color visual cryptography methods are free from the limitations of randomness on color images. The error diffusion and pixel synchronization are the two basic ideas, used for error filtering of the color images and to produce meaningful color shares. Error diffusion is a simple method, in which the quantization error at each pixel level is filtered and fed as input to the next pixel level. In this way, the low frequency that is obtained between the input and output image is minimized which in turn gives quality images and degradation of colors is avoided with the help of pixel synchronization. The color image visual cryptic filtering scheme presents a deblurring effect on the non-uniform distribution of visual cryptic share pixels. After eliminating blurring effects on the pixels, Fourier transformation is applied to normalize the unevenly transformed share pixels on the original restored image. This in turn improves the quality of restored visual cryptographic image to its optimality. The overlapping portions of the two or multiple visual cryptic shares are filtered out with homogeneity of pixel texture property on the restored original image. Experimentation are conducted with standard synthetic and real data set images, which shows better performance of proposed visual cryptic filtering scheme of the color image. This proposed scheme is measured in terms of PSNR value (improved to 3 times) and the pixel error rate (reduced to nearly 11%) with existing gray visual cryptic filters. The proposed method completely removes the noise effect of blurring when the original image is restored. INTERNATIONAL JOURNAL OF COMPUTER ENGINEERING & TECHNOLOGY (IJCET) ISS

Differential scanning calorimetry study of diffusional and martensitic phase transformations in some 9 wt-%Cr low carbon ferritic steels

The results of a comprehensive characterisation study of different phase transformations that take place upon heating and cooling in some low carbon, 9?wt?%Cr steels with varying concentrations of microalloying additions are presented in this paper. The steels investigated include: standard 9Cr?1Mo grade, V and Nb added modified 9Cr variety, controlled silicon added versions of plain 9Cr variety, (Ni+Mn) content controlled modified 9Cr welding consumables and one composition of W, Ta added reduced activation steel. The various on?heating diffusional phase changes up to the melting range and subsequent rapid cooling induced martensitic transformations are investigated in a controlled manner using differential scanning calorimetry under different heating and cooling rates, in the range 1?100?K?min?1. In addition to the accurate determination of Ac1, Ac3, M23C6, MX carbide dissolution and ??ferrite formation temperatures upon heating, the melting range and the associated fusion enthalpy have also been established for these steels. The effect of prolonged thermal aging at temperatures of 823?873?K on austenite formation characteristics has also been investigated for standard and modified 9Cr?1Mo steels. The critical cooling rate for the formation of martensite on cooling from single phase austenite region is estimated to be about 4?5?K?min?1 for all 9Cr steels investigated in this study. The effect of holding at 1273?K in the austenite region on martensite start temperature Ms, has also been evaluated as a part of this study. The experimental results are discussed in the light of the prevailing understanding of the physical metallurgy of high chromium low carbon steels

Measurement of transformation temperatures and specific heat capacity of tungsten added reduced activation ferritic-martensitic steel

The on-heating phase transformation temperatures up to the melting regime and the specific heat capacity of a reduced activation ferritic-martensitic steel (RAFM) with a nominal composition (wt%): 9Cr-0.09C-0.56Mn-0.23V-1W-0.063Ta-0.02N, have been measured using high temperature differential scanning calorimetry. The α-ferrite + carbides → γ-austenite transformation start and finish temperatures, namely Ac<SUB>1</SUB>, and Ac<SUB>3</SUB>, are found to be 1104 and 1144 K, respectively for a typical normalized and tempered microstructure. It is also observed that the martensite start (M<SUB>S</SUB>) and finish (M<SUB>f</SUB>) temperatures are sensitive to the austenitising conditions. Typical M<SUB>S</SUB> and M<SUB>f</SUB> values for the 1273 K normalized and 1033 K tempered samples are of the order 714 and 614 K, respectively. The heat capacity C<SUB>P</SUB> of the RAFM steel has been measured in the temperature range 473-1273 K, for different normalized and tempered samples. In essence, it is found that the C<SUB>P</SUB> of the fully martensitic microstructure is found to be lower than that of its tempered counterpart, and this difference begins to increase in an appreciable manner from about 800 K. The heat capacity of the normalized microstructure is found to vary from 480 to 500 J kg<SUP>−1</SUP> K<SUP>−1</SUP> at 500 K, where as that of the tempered steel is found to be higher by about, 150 J kg<SUP>−1</SUP> K<SUP>−1</SUP>

Cyfip1 Haploinsufficiency Increases Compulsive-Like Behavior and Modulates Palatable Food Intake in Mice: Dependence on Cyfip2 Genetic Background, Parent-of Origin, and Sex.

Binge eating (BE) is a heritable trait associated with eating disorders and involves episodes of rapid, large amounts of food consumption. We previously identified cytoplasmic FMR1-interacting protein 2 (Cyfip2) as a genetic factor underlying compulsive-like BE in mice. CYFIP2 is a homolog of CYFIP1 which is one of four paternally-deleted genes in patients with Type I Prader-Willi Syndrome (PWS), a neurodevelopmental disorder whereby 70% of cases involve paternal 15q11-q13 deletion. PWS symptoms include hyperphagia, obesity (if untreated), cognitive deficits, and obsessive-compulsive behaviors. We tested whether Cyfip1 haploinsufficiency (+/-) would enhance compulsive-like behavior and palatable food (PF) intake in a parental origin- and sex-dependent manner on two Cyfip2 genetic backgrounds, including the BE-prone C57BL/6N (Cyfip2 N/N) background and the BE-resistant C57BL/6J (Cyfip2 J/J) background. Cyfip1 +/- mice showed increased compulsive-like behavior on both backgrounds and increased PF intake on the Cyfip2 N/N background. In contrast, maternal Cyfip1 haploinsufficiency on the BE-resistant Cyfip2 J/J background induced a robust escalation in PF intake in wild-type Cyfip1 J/J males while having no effect in Cyfip1 J/- males. Notably, induction of behavioral phenotypes in wild-type males following maternal Fmr1 +/- has previously been reported. In the hypothalamus, there was a paternally-enhanced reduction in CYFIP1 protein whereas in the nucleus accumbens, there was a maternally-enhanced reduction in CYFIP1 protein. Nochange in FMR1 protein (FMRP) was observed in Cyfip1 +/- mice, regardless of parental origin. To summarize, Cyfip1 haploinsufficiency increased compulsive-like behavior and induced genetic background-dependent, sex-dependent, and parent-of-origin-dependent effects on PF consumption and CYFIP1 expression that could have relevance for neurodevelopmental and neuropsychiatric disorders