Embedded color error diffusion

Color halftoning is a method for representing continuous tone color images with limited colors. To implement halftone, error diffusion is one of the most popular algorithms due to its highperformance results. In the conventional error diffusion, the fixed thresholds and filter weights are used. In the process, many artifacts are introduced in the halftone images as side effects. With the color aspect, each of the three color planes is independently calculated during the process of traditional error diffusion. However, the pattern of dots formed independently by combining the dots of each of color planes is often not visually pleasing because no effort is made to insure that the dots of each of the different color planes are ideally distributed relative to the dots of the other color planes. In this paper, we present an integrated error diffusion algorithm in which variable filter weights, threshold matrix, serpentine scan path and multi-color halftoning are used to reduce the noises generated during the halftone process. Our experimental results showed that worm-like artifacts, structural artifacts and start-up artifacts are successfully decreased and the color halftoned images are more comfortable to the human visual system.

Steganography is the process of embedding data into a media form such as image, voice, and video. The major methods used for data hiding are the frequency domain and the spatial domain. In the frequency domain, the secret data bits are inserted into the coefficients of the image pixel's frequency representation such as Discrete Cosine Transform (DCT) , Discrete Fourier Transform (DFT) and Discrete Wavelet Transform (DWT) . On the other hand, in the spatial domain method, the secret data bits are inserted directly into the images' pixels value decomposition. The Lest Significant Bit (LSB) is consider as the most widely spatial domain method used for data hiding. LSB embeds the secret message's bits into the least significant bit plane( Binary decomposition) of the image in a sequentially manner . The LSB is simple, but it poses some critical issues. The secret message is easily detected and attacked duo to the sequential embedding process. Moreover, embedding using a higher bit plane would degrade the image quality. In this paper, we are proposing a novel data hiding method based on Lucas number system. We use Lucas number system to decompose the images' pixels values to allow using higher bit plane for embedding without degrading the image's quality. The experimental results show that the proposed method achieves better Peak Signal to Noise Ratio ( PSNR) than the LSB method for both gray scale and color images. Moreover, the security of the hidden data is enhanced by using Pseudo Random Number Generators(PRNG) for selecting the secret data bits to be embedded and the image's pixels used for embedding.

We have previously developed a two-dimensional monochromatic halftoning with error diffusion neural networks (EDNs). We showed that EDNs find local minima of frequency-weighted error between a binary halftone output and corresponding smoothly varying input, an ideal framework for solving halftone problems. The advantage of the neural algorithm is that all pixel quantization decisions are computed in parallel and therefore the error diffusion process becomes un-directional and symmetric. Thus eliminates the artifacts caused by the traditional error diffusion method. This paper casts color halftoning as four related sub-problems: the first three are to compute good binary halftones for each primary color and the fourth is to simultaneously minimize frequency-weighted error in the luminosity of the composite result. We show that an EDN with a three-dimensional interconnect scheme can solve all four problems in parallel with user-adjustable emphasis on the relative importance of weighted error in luminosity. Our results show that the three-dimensional EDN matrix not only shapes the error to frequencies that human visual system (HVS) is least sensitive but also shapes the error in colors to which the HVS is least sensitive - namely it satisfies the minimum brightness variation criterion.

An improved method is presented for coding the atoms found by the matching pursuits algorithm used in compressing displaced frame difference (DFD) images in motion compensated video coding. A list of atoms is collected, which are then communicated in the order of their most significant bit plane, rather than being communicated as they are found. The atom positions are run length coded, with the sign, extra bits of magnitude and code-book entry sent as side information. The magnitudes are represented by the most significant bit plus a specified number of additional bits. The distortion is never worse than the standard coding method, and can be up to 1dB better. The magnitude precision for best PSNR is found to be 2 at low bit rates and 1 at high bit rates in the examples considered.

A sweeping computational ghost imaging (SCGI)-based encryption system is intended for increased data security and speedier data transport. SCGI is combined with steganography and cryptography processes in this system. SCGI requires fewer shots, resulting in faster image capture, transmission, encryption, and decryption. This strategy also results in smaller, more compact data packages and higher bitrates. Least significant bit (LSB) uses steganography to conceal the hidden picture. In the case of Rivest–Shamir–Adleman (RSA) encryption, public and private keys are generated via a one-way function based on bucket values. Encryption is performed on two levels, with an asymmetric approach divided into three sub-items that significantly increase encryption. Surprisingly, the method uses fewer pictures for image reconstruction, resulting in faster image reconstruction. SCGI promises applications in an extensive number of data encryption sectors since this technology leads to smaller data packages and higher bitrates. The presented approach is examined using the number of pixel change rate (NPCR), normalized root mean square (NRMS), peak signal-to-noise ratio (PSNR), and correlation coefficient (CC), which indicates constant encryption improvement. We experimentally and situationally demonstrate our findings under eavesdropping, which prove the resistance and robustness of our methods. In optimal settings, this innovation enhances encryption by up to 90% when compared to traditional encryption methods.

The process of conversion of continuous tone image to discrete dots is called halftoning. The existing halftoning techniques are not suitable for all types of images. Hence, in this paper, the contrast of color halftone image is enhanced using the proposed error diffusion with varying threshold (EDVT) halftoning. This algorithm is the combination of point processing and neighborhood processing halftoning techniques. EDVT color halftoning varies the threshold for each block of pixels, and also it diffuses the quantization error to the neighboring pixels. The simulation results have been carried out for color halftone images using EDVT halftoning algorithm, and it is analyzed with the quality parameters which reveals that it has improved quality than the existing halftoning techniques.

The paper proposes a novel chaos based audio steganography and cryptography method. It is a higher Least Significant Bit (LSB) layers algorithm in which the secret message is encrypted first by one-time pad algorithm. Two chaotic sequences of Piecewise Linear Chaotic Map (PWLCM) were used. In the encryption process, the key for one-time pad is generated by PWLCM chaotic map. In the steganography process, the second sequence of PWLCM is used to generate a random sequence. Then, indices of the ordered generated sequence were used to embed the encrypted message in randomly selected audio samples. The encrypted data were embedded on the higher layers other than the LSB using efficient bits adjustment algorithm, in order to increase the robustness against noise addition or MPEG compression. An analysis is discussed for the proposed scheme. For the steganography algorithm, the proposed scheme overcomes the main two problems for LSB coding, which are the low robustness of secret message extraction and destruction. For the former, the proposed method encrypts the secret message by perfect efficient algorithm which is the one-time pad. Regard of the second one, the secret message is hidden in higher layers which improve the robustness against signal processing manipulation. The main three steganography characteristics were tested and evaluated which are high capacity, perceptual transparency and robustness. Furthermore, the drawbacks of key generation and key distribution for one-time pad is sloved by using the chaotic maps. For the experimental results, waveform analysis and signal-to-noise Ratio are made, which show the high quality of the stego audio, and hence demonstrate the efficiency of the proposed scheme.

Audio steganography using bit modification of time domain audio samples is a simple technique for multimedia data embedding with potential for large payload. Depending on the index of the bit used to modify the samples in accordance with the data to be hidden, the resulting stego audio signal may become perceptible and/or susceptible to incorrect retrieval of the hidden data. This paper presents some results of the tradeoff between the conflicting requirements of data robustness, payload and imperceptibility. Experimental results on both clean and noisy host audio signals indicate that while the payload can be as high as over 3000 bits/s - much higher rate than common audio data embedding techniques - noticeability of embedding is decreased and noise tolerance increased by using higher bit indices than the traditional least significant bit. Bit error rates of below one percent were observed for data retrieved from noise-added stego audio signals with 39 dB of SNR for an embedded payload of over 10 Kbits in a 3.3 s host audio.

To enhance the payload of secret data a scheme on the basis of least significant bit (LSB) substitution cascaded with pixel value differencing (PVD) has been proposed in this paper. Firstly secret bits are embedded using PVD method where smooth areas obtain small number of bits and higher bits in the edged area. Then bits are also embedded in the same pixel block by applying LSB replacement method as a cascading manner. The technique ensures more hiding capacity along with security as two methods are applied as cascaded manner on the same pixel block. Experimental result shows that proposed method can hide nearly double amount of secret data, compared to PVD method with good visual quality of stego-images.

In this paper, we propose a viewing direction weighted bit plane least significant bit (LSB) data hiding method for 360° videos. Normalized Gaussian mixture models (GMMs) of the distributions of the relative viewing direction frequency for latitude, longitude, and both latitude and longitude are used to describe the human viewing behavior of 360° videos on head-mounted displays (HMDs). Apart from formulating data hiding weight functions to control the amount of secret data to be hidden at given latitudes and longitudes, the GMMs are used in this work also to define viewing direction weighted bit plane functions. These viewing direction weighted bit plane functions specify the number of bit planes to be used for data hiding depending on the latitude and longitude. As humans pay more attention to the central front view of 360° videos when watched on HMDs, the number of engaged bit planes is decreased accordingly from the poles to the equator, and from the west and the east to the front view. A performance assessment of the proposed viewing direction weighted bit plane LSB data hiding method is conducted, showing the trade-offs between capacity and objective perceptual video quality. The results indicate that it is preferable to first utilize a given bit plane for data hiding in an entire 360° video frame before engaging the next higher bit plane subject to the viewing direction weighted bit plane functions.

A hardware implementation of a high-speed device for reducing numbers modulo is considered. We used a modified division algorithm with a shift of the dividend, where at each step n + 3 most significant bits of the dividend, and then the resulting remainders, participate. The shift of the reduced number at each step by three bits to the left towards the higher bits shifted and it makes it possible to speed up the process of reduction in modulus by reducing the number of modular reduction steps. The main unit of the device is a block of partial remainder formers (PRFs), which use subtraction of the P modulus and multiples of the P modulus.

In this paper a human visual system (HVS) model guided least significant bit (LSB) watermarking approach for copyright protection is proposed. The projected algorithm can embed more information into less featured surrounded areas within the host image determined by phase congruency. Phase congruency offers a dimensionless quantity which is an excellent measure feature points with high information and low in redundancy within an image. The region with fewer features indicates the most trivial visible aspects of an image, so alteration within these areas will be less noticeable to any viewer. Furthermore the algorithm will be tested by means of imperceptibility and robustness. Thus a new spatial domain image watermarking scheme will be projected with higher bit capacity.KeywordsHVSLSBCopyright protectionPhase congruencyimage watermarking

This paper proposes a steganography technique to hide secret messages in the least significant bits of the pixels of the cover image which are most different from their neighbourhood pixels. Since such pixels are the areas in an image which correspond to great changes in the visual property, they make a better option to hold secret data than smoother regions of the image, where a small distortion is much more noticeable. This paper uses LSB Matching algorithm for data embedding and the embedding method is adaptive to the amount of data in the message. Smaller is the amount of data, higher the value of threshold is chosen. The proposed technique is tested on BOWS2 Database consisting 10000 images and is compared with current steganography techniques for their robustness against various steganalysis methods. The proposed technique has given overall better results as compared to other techniques.

The efficiency of a Steganographic technique depends on its visual imperceptibility as well as resistance to various attacks. The paper aims to evaluate quantitatively various methods of implementing Image Steganography in spatial domain. Least Significant Bit (LSB) technique implemented here is one of the most common methods followed, owing to its simplicity. Bit plane slicing technique provides for better bandwidth efficiency, while XOR embedding and encryption algorithm like SVD enhance the level of security to the process. Evaluation of various techniques is made with Non-linear regression of Mean Squared Error (MSE) and Peak Signal-to-Noise-Ratio.

This paper proposes a high-speed MSB first multiplier which works efficiently when successive inputs show gradual change which is usually the case for analog signals sampled at a high rate. When the speed of execution of various processes in digital signal processing units is considered, the easiest way to improve it is to use efficient and fast multiplier units. The proposed multiplier computes only one or two partial products when the successive inputs are similar as compared to eleven partial products in the conventional multiplier. The output truncation length can be controlled depending upon the application. The no. of clock cycles needed for multiplication in a conventional MSB first multiplier and the proposed highspeed multiplier are compared through FPGA Implementation. An average decrease of 14.7% in no. of clock cycles is observed when simulations are done for 1400 ECG ambulatory recordings from MIT BIH Arhythmia Database.