An enhanced method based on intermediate significant bit technique for watermark images

Intermediate Significant Bit digital watermarking technique (ISB) is a new approved technique of embedding a watermark by replacing the original image pixels with new pixels. This is done by ensuring a close connection between the new pixels and the original, and at the same time, the watermark data can be protected against possible damage. One of the most popular methods used in watermarking is the Least Significant Bit (LSB). It uses a spatial domain that includes the insertion of the watermark in the LSB of the image. The problem with this method is it is not resilient to common damage, and there is the possibility of image distortion after embedding a watermark. LSB may be used through replacing one bit, two bits, or three bits; this is done by changing the specific bits without any change in the other bits in the pixel. The objective of this thesis is to formulate new algorithms for digital image watermarking with enhanced image quality and robustness by embedding two bits of watermark data into each pixel of the original image based on ISB technique. However, to understand the opposite relationship between the image quality and robustness, a tradeoff between them has been done to create a balance and to acquire the best position for the two embedding bits. Dual Intermediate Significant Bits (DISB) technique has been proposed to solve the existing LSB problem. Trial results obtained from this technique are better compared with the LSB based on the Peak Signal to Noise Ratio (PSNR) and Normalized Cross Correlation (NCC). The work in this study also contributes new mathematical equations that can study the change on the other six bits in the pixel after embedding two bits

Watermarking technique based on ISB (Intermediate Significant Bit)

Digital watermarking is a special case of the general information hiding problem. It inserts a perceptually transparent pattern called watermark in an image called host or cover using an embedding algorithm. The purpose of the watermark is to supply the ownership of the image or copyright protection information. The energy of the embedded data should be low enough when projected onto the human perception domain but it should be strong enough for robust machine detection. Least Significant Bit (LSB) technique is the earliest developed technique in watermarking and it is also the most simple, direct and common technique. It essentially involves embedding the watermark by replacing the least significant bit of the image data with a bit of the watermark data. The disadvantage of LSB is that it is not robust against attacks. The aim of this study is to develop a robust watermarking model using spatial domain technique and at the same time maintaining important watermarking requirements of picture quality. The new model has been developed based on intermediate significant bit (ISB) aim to replace the watermarked image pixels by new pixels that can protect the watermark data against attacks and at the same time keeping the new pixels very close to the original pixels in order to protect the quality of watermarked image. The technique is based on testing the value of the watermark pixel according to the range of each bit-plane. The main contribution of this research is replacing the classic least significant bits (LSB) technique by a new technique called intermediate significant bits ISB, which improves the robustness and maintains the quality of watermarked images

On the application of two dimensional chirplets for resilient digital image watermarking

Chirplets (swept-frequency harmonic signals) find applications in several areas, including real and synthetic aperture radar, (Fresnel) optics and image processing. The robustness of chirplets to extreme (additive) noise make them an ideal choice in the role of embedding patterns for resilient digital signal and image watermarking. In this paper we present a new watermarking technique which is based on embedding twodimensional chirplet coded binary sequences in digital images. This approach provides a pattern embedded recovery algorithm which is robust to a variety of distortions. However, chirplets have certain parameters that need to be specified, and, given a set of target characteristics, some particular chirplet parameters can be considered optimal. This paper reports on the optimisation of both the chirplet sets and their associated parameters focusing on a classification of their resilience to image distortion

A New Digital Watermarking Algorithm Using Combination of Least Significant Bit (LSB) and Inverse Bit

In this paper, we introduce a new digital watermarking algorithm using least significant bit (LSB). LSB is used because of its little effect on the image. This new algorithm is using LSB by inversing the binary values of the watermark text and shifting the watermark according to the odd or even number of pixel coordinates of image before embedding the watermark. The proposed algorithm is flexible depending on the length of the watermark text. If the length of the watermark text is more than ((MxN)/8)-2 the proposed algorithm will also embed the extra of the watermark text in the second LSB. We compare our proposed algorithm with the 1-LSB algorithm and Lee's algorithm using Peak signal-to-noise ratio (PSNR). This new algorithm improved its quality of the watermarked image. We also attack the watermarked image by using cropping and adding noise and we got good results as well.Comment: 8 pages, 6 figures and 4 tables; Journal of Computing, Volume 3, Issue 4, April 2011, ISSN 2151-961