A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> This paper proposes a novel fragile watermarking scheme capable of perfectly recovering the original image from its tampered version. In the scheme, a tailor-made watermark consisting of reference-bits and check-bits is embedded into the host image using a lossless data hiding method. On the receiver side, by comparing the extracted and calculated check-bits, one can identify the tampered image-blocks. Then, the reliable reference-bits extracted from other blocks are used to exactly reconstruct the original image. Although content replacement may destroy a portion of the embedded watermark data, as long as the tampered area is not too extensive, the original image information can be restored without any error. <s> BIB001 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> In this paper, we propose a novel self-recovery watermarking scheme based on dual-redundant-ring structure (DRRS). All blocks of target image form a ring in a manner that the watermark of an image block is hidden in 1-LSB (least significant bit) of its next block N"1, and the copy of this watermark is embedded into 2-LSB of another block whose position is determined by the position of N"1. The validity of test image block is determined by comparing the number of inconsistent blocks in the block-neighborhood with that of its mapping block. Other detection result is generated in the same way comparing test block with copy block of its next block. The fusion of two detection marks improves tamper detection accuracy, while two copies of watermark provide a second chance for tamper recovery. Experimental results demonstrate that the proposed algorithm is superior to the state of the art of tamper detection and tamper recovery and could keep high security strength. <s> BIB002 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> In this paper, we present a new fragile watermarking method aimed at providing improved tampering localisation and self-recovery capabilities. First, a secure block-wise mechanism, resilient to cropping, is used to localise distorted blocks of pixels. Subsequently, the tampering localisation accuracy is refined by means of an iterative pixel-wise mechanism, which estimates the original watermarked pixels in altered regions. Extensive tests, using a large data-set, are presented to show to what extent the size of the tampered area influences the performance of our method. Moreover, results show that the proposed scheme compares favourably with a method presented in recent literature, in terms of tampering localisation and self-recovery performance. In fact, we show that our method is capable of partially reconstructing a cover image when 5% of its total number of pixels has been cropped. <s> BIB003 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> In this paper, we present the performance analysis of a self-recovery fragile watermarking scheme using block-neighbor- hood tamper characterization. This method uses a pseudorandom sequence to generate the nonlinear block-mapping and employs an optimized neighborhood characterization method to detect the tampering. Performance of the proposed method and its resistance to malicious attacks are analyzed. We also investigate three optimization strategies that will further improve the quality of tamper localization and recovery. Simulation results demonstrate that the proposed method allows image recovery with an acceptable visual quality (peak signal-to-noise ratio (PSNR) as 25 dB) up to 60% tampering. <s> BIB004 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <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> BIB005 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> Utilize relationships of singular values to extract content-dependent watermark.Merge relationships of singular values to choose adaptive quantizer for each block.Apply adaptive quantization to embed secure watermark in the wavelet domain.Define a 3-level authentication process to detect authenticity and prove tampering.Use five measures to compensate misclassification and capture distortions. This paper presents a singular-value-based semi-fragile watermarking scheme for image content authentication. The proposed scheme generates secure watermark by performing a logical operation on content-dependent watermark generated by a singular-value-based sequence and content-independent watermark generated by a private-key-based sequence. It next employs the adaptive quantization method to embed secure watermark in approximation subband of each 4i?4 block to generate the watermarked image. The watermark extraction process then extracts watermark using the parity of quantization results from the probe image. The authentication process starts with regenerating secure watermark following the same process. It then constructs error maps to compute five authentication measures and performs a three-level process to authenticate image content and localize tampered areas. Extensive experimental results show that the proposed scheme outperforms five peer schemes and its two variant systems and is capable of identifying intentional tampering, incidental modification, and localizing tampered regions under mild to severe content-preserving modifications. <s> BIB006 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> Abstract To address issues of image authenticity verification and integrity protection, a fragile watermarking method for stereo image authentication is proposed with stereo matching technique. According to stereo matching of left and right images, non-overlapping blocks of left image are classified into non-matchable and matchable ones. Right image blocks and non-matchable blocks of left image are categorized into smooth, texture and complex blocks considering their roughness. Then, the corresponding alterable-length watermark is computed based on the results of block classification, and the destroyed blocks are recovered by using the corresponding alterable-length watermark. Besides, matchable tampered blocks of left image are recovered with the matched contents in right image. A detection technique with the part of alterable-length watermark is used to increase accuracy of tamper localization at the receiver. The disparity can be used to recover the tampered matchable block. Therefore, the quality of watermarked images is improved because of low embedding capacity. Additionally, the alterable-capacity watermark provides suitable information for smoother images with fewer bits and we obtain high quality restoration. Experimental results show that the proposed method can not only localize the tampered regions precisely but also recover the tampered regions with higher quality compared with the state-of-the-art methods. <s> BIB007 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> Digital image authentication has become a hot topic in the last few years. In this paper, a pixel-based fragile watermarking method is presented for image tamper identification and localization. By analyzing the left and right singular matrices of SVD, it is found that the matrix product between the first column of the left singular matrix and the transposition of the first column in the right singular matrix is closely related to the image texture features. Based on this characteristic, a binary watermark consisting of image texture information is generated and inserted into the least significant bit (LSB) of the original host image. To improve the security of the presented algorithm, the Arnold transform is applied twice in the watermark embedding process. Experimental results indicate that the proposed watermarking algorithm has high security and perceptual invisibility. Moreover, it can detect and locate the tampered region effectively for various malicious attacks. <s> BIB008 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Block mapping sequence <s> The rapid growth in Internet and communication technology has facilitated an escalation in the exchange of digital multimedia content. This has resulted in an increase in copyright infringement, which has led to a greater demand for more robust copyright protection mechanisms. Digital watermarking is a means of detecting ownership and illegal use of digital products. This paper presents an approach to watermarking images by embedding QR code information in a digital image. The notion of the proposed scheme is to capitalize on the error correction mechanism that is inherent in the QR code structure, in order to increase the robustness of the watermark. By employing the QR code’s error correction mechanism, watermark information contained within a watermarked image can potentially be decoded even if the image has been altered or distorted by an adversary. This paper studies the characteristics of the proposed scheme and presents experiment results examining the robustness and security of the QR code watermarking approach. <s> BIB009
In the self-embedding watermark scheme, block mapping is done before the watermark insertion process. In this case, a certain block feature will be inserted as a watermark payload for another block. In BIB004 , it is mentioned that block mapping procedures are available but are generally grouped into linear transformations: 2-D transformations BIB001 BIB002 as shown in Eq. (1), and 1-D linear transformations BIB008 BIB003  as shown in Eq.  . Where a point (x i + 1 , y i + 1 ) can be transformed from another point (x i , y i ) and ( , N is the total number of blocks in the image. For 1-D transformation, a one-to-one mapping sequence was obtained as shown in Eq. 2 Where X, X ′ ∈ [0, N − 1], k is a secret key and N is the total number of blocks in the image. However, due to the limited number of degrees of freedom, linear transformations can be easily reconstructed by only experimenting with some sample images, and other weaknesses are low security  BIB006 . To solve this problem, He et al. BIB005 have proposed a nonlinear block mapping construction using a pseudorandom sequence. A block mapping sequence B is computed from a key based pseudorandom permutation The differences between pseudorandom and 1-D transformation can be seen in Fig. 5 . Where for an even number key, on 1-D transformation there is a repetition, so it does not produce one-to-one mapping. Another method for pixel scrambling has been adopted in Chow et al.'s Scheme BIB009 , which is the Arnold transform. By using the Arnold transformation shown in Eq. 3, high pixel correlation can be dissociated. Where (x, y) is the initial pixel positions, (x ′ , y ′ ) is the positions after transformation and p and q are positive integers, which are used to determine the period of a given matrix. Det (A) = 1, N is the total number of blocks in the image. Correlations between adjacent pixels can be solved by applying multiple iterations. Shruthy et al.  and Yu et al.'s BIB007 methods use pseudorandom sequences to generate nonlinear block mapping and use an optimal environmental characterisation method to detect the disturbance. Method  also investigates three optimisation strategies which will further improve the quality of localisation and tamper recovery. They take all the blocks of adjacent test blocks and their mapping blocks and then take advantage of statistical rules to determine the validity of the image blocks. Based on the false acceptance analysis and the probability of a false rejection, post-processing operations are presented to improve the further performance of the proposed human resources. This includes three steps: (1) marking the dubious block, (2) distinguishing blocks that are damaged from dubious blocks with adjacent blocks and (3) improving detection performance by post-detection processing BIB007 . 