scholarly journals Lossy codecs for digital image signatures

2021 ◽  
Vol 3 (2) ◽  
pp. 92-101
Author(s):  
Benjamin Kommey ◽  
Seth Kotey ◽  
Gideon Adom-Bamfi ◽  
Eric Tutu Tchao
Keyword(s):  
Digital Image ◽  
Image Coding ◽  
Digital Signature ◽  
The Other ◽  
Transform Coding ◽  
Ongoing Research ◽  
Storage Devices ◽  
Human Eye ◽  
Finite Resource

Most applications in recent times make use of images one way or the other. As physical devices for capturing images improve, the quality and sizes of images also increase. This causes a significant footprint of images on storage devices. There is ongoing research to reduce the footprint of images on storage. Since storage is a finite resource, the goal is to reduce the sizes of images while maintaining enough quality pleasant to the human eye. In this paper, the design of two lossy codecs for compressing grayscale digital signature images has been presented. The algorithms used either simple thresholding or transform coding to introduce controlled losses into the image coding chain. This was to reduce, to a great extent, the average number of bits per pixel required to represent the images. The codecs were implemented in MATLAB and experiments were conducted with test images to study the performances of the algorithms.

PERBANDINGAN METODE MD4 DAN SHA 384 UNTUK MENDETEKSI ORISINALITAS CITRA DIGITAL

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Lemcia Hutajulu ◽  
Hery Sunandar ◽  
Imam Saputra
Keyword(s):  
Digital Image ◽  
Detrimental Effect ◽  
Digital Images ◽  
Computer Crime ◽  
The Other ◽  
Image Manipulation ◽  
The Internet ◽  
Secret Key

Cryptography is used to protect the contents of information from anyone except those who have the authority or secret key to open information that has been encoded. Along with the development of technology and computers, the increase in computer crime has also increased, especially in image manipulation. There are many ways that people use to manipulate images that have a detrimental effect on others. The originality of a digital image is the authenticity of the image in terms of colors, shapes, objects and information without the slightest change from the other party. Nowadays many digital images circulating on the internet have been manipulated and even images have been used for material fraud in the competition, so we need a method that can detect the image is genuine or fake. In this study, the authors used the MD4 and SHA-384 methods to detect the originality of digital images, by using this method an image of doubtful authenticity can be found out that the image is authentic or fake.Keywords: Originality, Image, MD4 and SHA-384

On cataract operation according to the data of the Ophthalmological Clinic of Kazan University for 20 years (from 1899 to 1919)

1923 ◽  
Vol 19 (3) ◽  
pp. 50-59
Author(s):  
V. P. Roshchin
Keyword(s):  
Cataract Extraction ◽  
The Other ◽  
Cataract Operation ◽  
Lens Extraction ◽  
Human Eye ◽  
Surgical Method

The question of cataract extraction - mainly senile - or, more precisely, of the advantages of one or the other surgical method, despite its antiquity and considerable literature, has not lost interest in the eyes of oculists to this day. The fact is that the operation of lens extraction is one of the most important and most demanding on the human eye. Meanwhile, there is no flawless, perfect method of this operation, and every one of them - and there are many - has flaws of one kind or another. Naturally, therefore, ophthalmologists have widely differing opinions on the suitability of one method or another.

scholarly journals Comparison of Multicast Algorithm Evaluation Results in Low and High Multicast Saturation Environments

2019 ◽  
Vol 3 ◽  
pp. 3-7
Author(s):  
Krzysztof Stachowiak ◽  
Piotr Zwierzykowski
Keyword(s):  
Quality Of Service ◽  
Computational Complexity ◽  
Optimization Methods ◽  
The Other ◽  
Ongoing Research ◽  
Mathematical Problems ◽  
Point To Point ◽  
Difficult Challenge ◽  
Entire Network

The multicast quality of service-enabled routing is a computationally challenging task. Despite ongoing research efforts, the associated mathematical problems are still considered to be NP-hard. In certain applications, computational complexity of finding the optimal connection between a set of network devices may be a particularly difficult challenge. For example, connecting a small group of participants of a teleconference is not much more complex than setting up a set of mutual point-to-point connections. On the other hand, satisfying the demand for such services as IPTV, with their receivers constituting the majority of the network, requires applying appropriate optimization methods in order to ensure real system execution. In this paper, algorithms solving this class of problems are considered. The notion of multicast saturation is introduced to measure the amount of multicast participants relative to the entire network, and the efficiency of the analyzed algorithms is evaluated for different saturation degrees.

Modified No Search Scheme based Domain Blocks Sorting Strategies for Fractal Image Coding

2014 ◽  
Vol 69 (10-11) ◽  
pp. 511-520
Author(s):  
Xing-Yuan Wang ◽  
Dou-Dou Zhang ◽  
Na Wei
Keyword(s):  
Mean Square Error ◽  
Image Coding ◽  
The Other ◽  
Mean Square ◽  
Minimum Value ◽  
Fractal Image ◽  
Fractal Image Coding ◽  
Domain Block ◽  
Partition Method

AbstractA novel fractal image coding algorithm based on domain blocks sorting strategies and modified no search scheme is proposed in this paper. On one hand, in order to improve the encoding time, a modified no search (MNS) scheme is adopted. Firstly, the image is divided into blocks of different size utilizing an adaptive quadtree partition method. Secondly, one finds the location of the best matching domain block using the MNS scheme for the range blocks, whose sizes are larger than the preset minimum value. Thirdly, the types of the range block and domain block are computed employing the proposed approach, and then the corresponding computation of mean square error (MSE) is determined. The computation of the MSE is reduced and the encoding phase speeds up. On the other hand, the range blocks with the minimal sizes are encoded applying the proposed domain blocks sorting (DBS) method. Contrast experiment results show that the proposed algorithm can obtain good quality of the reconstructed images and shorten the encoding time significantly.

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