A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> This paper presents a semi-fragile watermarking technique capable of verifying the authenticity and recovery of the image. The proposed approach has the capability to accurately detect and differentiate modifications applied on the watermarked image. Alteration sensitivity has been improved compared to previous approaches and it can concisely determine the region of the watermarked image where the integrity verification fails. Semi-fragility makes the proposed method tolerant against JPEG lossy compression and other acceptable modifications but sensitive to malicious attacks such as cutting and pasting. The exact low pass version of the image is recovered by using the lossless compression (Huffman coding). Simulation results demonstrate that the alteration sensitivity of the proposed authentication scheme is much better compared to the previous approaches. <s> BIB001 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> This paper proposes two novel self-embedding watermarking schemes based upon a reference sharing mechanism, in which the watermark to be embedded is a reference derived from the original principal content in different regions and shared by these regions for content restoration. After identifying tampered blocks, both the reference data and the original content in the reserved area are used to recover the principal content in the tampered area. By using the first scheme, the original data in five most significant bit layers of a cover image can be recovered and the original watermarked image can also be retrieved when the content replacement is not too extensive. In the second scheme, the host content is decomposed into three levels, and the reference sharing methods with different restoration capabilities are employed to protect the data at different levels. Therefore, the lower the tampering rate, the more levels of content data are recovered, and the better the quality of restored results. <s> BIB002 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> Digital Watermarking is a technique to embed additional data in digital images, without affecting the original image quality. It has become a useful tool for copyright protection, content authentication and steganography. Least Significant Bit is a commonly used technique in digital image watermarking. It is straight forward to understand and implement, and is widely used in many watermarking algorithms. A common problem of spatial LSB implementation is that a usual image compression can render watermark useless. In this paper we propose an alternative watermarking technique based on spatial LSB modification. It is robust against moderate JPEG compression, while keeping all the features of LSB. <s> BIB003 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> Abstract To take invisibility and restoration quality into account, this paper proposes an alterable-capacity watermarking scheme. For each block of size 8 × 8 pixels, the alterable-length code is generated based on the roughness of it. The alterable-length watermark generated by the alterable-length code is divided into three parts and embedded in other three blocks based on the secret key. The authenticity of each block is determined by comparing the watermark reconstructed by the block content and the corresponding extracted watermark. To improve the quality of recovered images, two copies of the significant-code of each block are embedded in different blocks and the image inpainting method is adopted to recover the tampered blocks whose significant-code embedded in other blocks is destroyed. The alterable-payload watermark preserves adequate information of image blocks especially for texture images with as few bits as possible and takes into account invisibility, security and restoration quality. Experimental results demonstrate that the proposed scheme improves the quality of watermarked and reconstructed images and is resilient to the known forgery attacks. <s> BIB004 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> This paper proposes a fragile image watermarking scheme with recover ability based on local binary pattern (LBP). The local binary pattern operator is mostly used to extract localized spatial features for texture analysis, image classification, and pattern recognition. According to spatial relations of a natural image, a local binary pattern can be utilized to represent the localized relations of a pixel with its neighborhood. Each pixel measured by the LBP operator can be obtained its own local binary pattern as representation of local spatial relations. The proposed scheme utilizes the LBP operator to generate authentication data which are embedded into each image block with 3 × 3 pixels size for tamper detection and recovery. The recovery information is obtained by calculating the mean value of each image block, and then the mean value is converted into a binary string which is embedded into eight neighboring pixels' LSBs of each image block for image recovering. From the experimental results, the proposed scheme has efficient tamper detection, better image quality and recovering ability than Zhang and Shih's LBP based watermarking scheme. <s> BIB005 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> This paper describes an image tamper detection and recovery method based on self-embedding dual watermarking. The watermark in the proposed method is a down-sampled version of an original image (cover image). Two identical watermarks are then decomposed into bit planes and embedded into the least-significant bit (LSB) plane of the cover image. This dual watermarking strategy ensures a robust performance in image tamper detection and recovery. Moreover, since the bit planes of the two identical watermarks are arranged in center-point-symmetric manner, image information is spread uniformly. This makes it possible to recover large area of tampering, such as, left, right, upper, or lower half of the cover image. Experimental results show that the proposed method is remarkably effective for detecting and recovering local image tampering, such as, image collage. <s> BIB006 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Review <s> DCT based effective self-recoverable fragile watermarking scheme is presented.This scheme has extreme localization and restoration capability.The blocking artifacts negligible because of using the small blocks of size 2×2.Two levels hierarchical tampered detection mechanisms are used for tampered block detection. This paper presents a Discrete Cosine Transformation (DCT) based effective self-recoverable fragile watermarking scheme. For each 2 × 2 non-overlapping block, two authentication bits, and ten recovery bits are generated from the five most significant bits (MSBs) of pixels. Authentication bits are embedded in the three least significant bits (LSBs) of the block itself while recovery bits are embedded in the three LSBs of the corresponding mapped block. The proposed watermarking scheme is also effective because the authentication of each block is based on two levels hierarchical tampered detection mechanisms. So the detection of tampered block can be ensured with high probability. The experimental results demonstrate that the proposed scheme not only outperforms high-quality restoration effectively, but also removes the blocking artifacts and improves the accuracy of tamper localization due to the use of very small size blocks, smoothing function and two levels tampering detection mechanisms. <s> BIB007
2.1 Basic principles of self-embedding fragile watermarking scheme In recent years, more research in the field of fragile watermarking is aimed at the process of damaged image authentication and recovery. This method can be derived under distinct purposes. According to the mechanism of image capture feature, it can be divided into block-wise and pixel-wise mechanisms as shown in Fig. 1 from Cheng et al.  ; the block-wise algorithm BIB007  BIB005 BIB001 BIB006 BIB002 divides the original image into small blocks to embed a watermark, which may be a hash of the main content taken from each block. The block-wise algorithm can locate the damaged block, but the blocks may contain some original pixels, so that the accuracy of the localisation placement is decreasing. This is the weakness of the block-wise algorithm. The pixel-based algorithm   BIB003 generates data from the original pixel grey value and embeds the mark into the pixel. By calculating the consistency of the extracted watermark and its derivative signal, we can detect the damaged pixels. However, due to the limited precision of biplanes, it is possible that the data derived from the damaged pixels equal the watermark even though it has been modified. Therefore, modifications to these pixels are not directly detected. There are two stages of the watermarking algorithm for image tamper detection and recovery; the embedding watermark phase and authentication phase which are then followed by tamper detection and recovery image BIB003 , as shown in the Figs. 2 and 3. Based on some characteristics, there are several categories used to estimate the effectiveness of a self-recovery fragile watermarking technique  BIB003 BIB004 : Perceptibility: the embedded watermark must be invisible. It will be hard to identify it with human vision; only authorised user will be able to recover it. The original cover image and the watermarked image are indistinguishable, and the recovered images should be of a high quality. Tamper detection: a self-recovery fragile watermarking technique must be able to detect with or without an original image or some information to derive it for the detection process. Tamper recovery: the scheme should be able to detect unauthorised modification on images and recover them from the tampered ones. Resistant to known attacks: the scheme should be as robust as it could to the well-known attacks, such as the general attack, the collage attack and the disturbing attack. In addition, some parameters used to measure the performance of watermarking algorithms are peak signal-to-noise ratio (PSNR) and bit-per-pixel (bpp). The value of PNSR can measure the perceptual comparison of the watermarked image to the original image BIB004  . Meanwhile, bpp is used to calculate the amount of watermark data inserted in the original image. The idle bpp value is 1, but there is a certain watermarking algorithm using more than 1 bpp.