Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : DCT


Secured Medical Image Hashing Based on Frequency Domain with Chaotic Map

Amira K. Jabbar; Ashwaq T. Hashim; Qusay F. Al-Doori

Engineering and Technology Journal, 2021, Volume 39, Issue 5A, Pages 711-722
DOI: 10.30684/etj.v39i5A.1786

Recently, online-medicine got increased global interest, particularly during COVID19 pandemic. Data protection is important in the medical field since when promoting telemedicine applications, it is necessary to protect the patient data and personal information. A secured process is needed to transmit medical images over the Internet. In this paper hash algorithm is employed to protect the data by using powerful features from the coupled frequency domains of the Slantlet Transformation (SLT) and the Discrete Cosine Transform (DCT). The Region of Interest (ROI) is localized from an MRI image then extraction of a feature set is performed for calculating the hash code. Then, hash code is enciphered to maintain security by employing a secure Chaotic Shift Keying (CSK). The suggested method of security is ensured by the strength of the CSK and the encryption key secrecy.  A detailed analysis was conducted using 1000 uncompressed images that were chosen randomly from a publicly available AANLIB database. The proposed methodology can be useful for JPEG compression. Also, this method could resist many attacks of image processing likes filtering, noise addition, and some geometric transforms.

Encrypted Image Watermark in Audio Files Using Homogenous Deffie-Hellman with Chebyshev Polynomial

Hala B. Abdul Wahab; Abdul-Mohssen J. Abdul-Hossen; Sana Ahmed Kadhom

Engineering and Technology Journal, 2016, Volume 34, Issue 6, Pages 894-900

Due to the expanding utilization of advanced media, the assurance of protected innovation rights issue has turned into an essential issue. Digital watermarking is currently drawing consideration as another technique for shielding media content from unapproved duplicating. In this paper, watermarking image (logo) will be encrypted using a key constructed by a proposed homogenous method of Diffie-Hellman and chebyshev polynomial. The encrypted watermark will be embedded in different samples from the transformed file (DCT) of audio. The embedding process will depend on binary similarity between the audio and watermark bits which reduces the effect of embedded data. The proposed method for the key generation is more secure and complicated since it combines the strength factors of both Diffie-Hellman and Chebyshev polynomial. The effect of the embedding is nonperceptibile and nondetectable.

Color Image Compression Using DPCM with DCT, DWT and Quadtree Coding Scheme

Ashwaq T. Hashim; Suhad A. Ali

Engineering and Technology Journal, 2016, Volume 34, Issue 4, Pages 585-597

This paper is concerned with the design and implementation of a compression method for color image. This method based on Differential Pulse Code Modulation (DPCM), Discrete Cosine Transform (DCT) , Discrete Wavelet Transform (DWT) and Quadtree Coding Scheme. As a first step the DPCM technique is used to isolate blocks of an image into correlated and uncorrelated blocks. The isolated correlated blocks have been compressed using DCT based compression method then each block has been embedded with zeros on the original image. Each uncorrelated block has been compressed using DWT based method and put the compressed block in its location on the original image. Then, the result (i.e., the zeros blocks and compressed blocks with DWT) coded using Quadtree spatial coding. The output from DWT based and DCT based passed through shift coding stage to gain a possible further compression. The performance results of proposed hybrid algorithms produces better quality of image in terms of Peak-Signal-to-Noise Ratio (PSNR) with a higher Compression Ratio (CR) compared to standalone DCT or DWT. The PSNR values of the reconstructed images after applying proposed system are ranged from 30.62 to 40.95dB and CR on average, have been reduced to be around 1:19.6 of the size of the original image.

Comparison of FFT-Based and DCT-Based Channel Estimation and ECC for OFDM System

Awatif Ali Jafaar

Engineering and Technology Journal, 2015, Volume 33, Issue 3, Pages 682-693

Orthogonal Frequency Division Multiplexing (OFDM) has become a popular modulation method for high data rate wireless communications. In this paper, two schemes are proposed. In the first scheme the Bit Error Rate (BER) and the Packet Error Rate(PER) performancesof Fast Fourier Transform-FFT based OFDM are compared with Discrete Cosine Transform DCT -based OFDM using (QPSK) and (16 QAM)as modulation techniques over Additive White Gaussian Noise environment (AWGN) and Multipath Rayleigh Fading environment.
To improve the performance of the uncoded OFDM schemes,the second coded scheme is investigated .Convolution coding is used to enhance the BER for the previous systems. The proposed systems have been tested and evaluated using MATLAB 7 package.

Hybrid Techniques for Proposed Intelligent Digital Image Watermarking

Bashar S Mahdi; Alia K. Abdul Hassan

Engineering and Technology Journal, 2015, Volume 33, Issue 4, Pages 702-713

Digital watermarking provides a solution of the recent problems such as a copyright protection and digital content authentication, as well as the balancing between the copyright protection and authentication requirements are the challenge of the many watermarking methods. In this paper, which is proposed a new intelligent watermarking methodto solve that problem by usingproposed hybrid techniques.
The proposed method can be describe by three phases, first one is employ the hybrid approach of visual cryptography and one way hash function which providing the security and authenticity to the watermarking system. Second one is concerned with intelligent embedding of watermark data in the cover image data by using three basics techniques which are the genetic algorithm, artificial neural networks and the human visual system model which obtains the effective balancing between the robustness and imperceptibility of the digital imageusing the middle frequency coefficients. Finally phase is depending on the extracting of the encrypted watermark by using the same operations of embedding stage and by using the overlapping approach in the visual cryptography. Experimental results demonstrates that the proposed methodprovidesa secure adaptive intelligent system which can apply in the different filed of application that need the reliable copyright protection with highly security and authenticity. Moreover, Obtaininga highly balancing among imperceptibility, robustness and security, that are showed by surviving the extracted watermark fromdifferent types of malicious and adaptive attacks.

Image Watermarking Using DWT_DCT

Bassim Abdulbaki Jumaa; Arwa Aladdin

Engineering and Technology Journal, 2010, Volume 28, Issue 23, Pages 6662-6675

Digital watermarking has been developed to protect digital images from
illegal manipulation. Discrete wavelet Transform (DWT) and Discrete Cosine Transform (DCT) are techniques used for digital watermarking. A combination of DWT and DCT techniques are used in this paper to meet imperceptibility, robustness and security requirements. Peak Signal to Noise Ratio (PSNR) and Bit Correct Ratio (BCR) measurements are used to study the effect of parameters: gain factor, threshold value, sub band, and image size on the watermark image. Many images are used to
embed the watermark image and the effects of parameters on the extracted
watermark image are studied. Then the optimal parameter values has been
specified.