A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> In this paper, we propose a scheme can be divided into two parts: one is about robust embedding of dual visual watermarks using DWT and Singular Value Decomposition (SVD), the other part is about tamper detection and self-recovery algorithm of color image. We stress on the latter part. Dual visual watermarks are original image watermark which is color scale image the same as original image and ownership watermark which is gray scale image, respectively. Both of them are embedded into original image using DWT-SVD to prove robustness. For recovery signal embedding, luminance signal and chrominance signal of original image were embedded into surplus chrominance space of original image using matrix transpose replacement embedding method. For watermark extraction scheme: firstly, threshold value would be set to find tampered region. Then we extract the recovery signals to construct recovery information. Lastly we replace tampered regions with recovery information based on threshold value. We can extract the original image watermark and ownership watermark from recovery image. Experiment demonstrates that the proposed scheme is robust to a wide range of attacks and is good at tampered detection as well as self- recovery of tampered images. <s> BIB001 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> Due to the wide variety of attacks and the difficulties of developing an accurate statistical model of host features, the structure of the watermark detector is derived by considering a simplified channel model. In this paper, we present a fragile watermarking based on block-mapping mechanism which can perfectly recover the host image from its tampered version by generating a reference data. By investigating characteristics of watermark detector, we make an effective analysis such as fragility against robustness measure and distinguish its property. In particular, we derive a watermark detector structure with simplified channel model which focuses on the error probability versus watermark-to-noise-ratio curve and describes a design by calculating the performance of technique, where attacks are either absent or as noise addition. <s> BIB002 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <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> BIB003 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> In recent decades, many watermarking schemes for tamper detection and tampered image recovery have been proposed. However, most of these schemes suffered from several kinds of attacks due to the lack of considering security issues. In this paper, an improved and elaborately designed scheme is proposed after the drawbacks of these schemes are analysed and discussed. The proposed scheme outperforms the other schemes in terms of the sensitivity to the alteration in the protected image as well as the resistibility to the well-known attacks, such as the counterfeit attack, the disturbing attack and the leakage of the secret key. In addition, the watermarked images and the recovered images generated by the proposed scheme demonstrate competent qualities. <s> BIB004 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <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> Watermark generation <s> Digital image processing technology presents new challenges for the security of the image information, which makes image authentication as a problem to be addressed. Digital watermarking plays an important role in multimedia information security. This paper proposed a dual watermarking method to do tamper location and self-recovery, which utilizes self-embedding technology to hide eigenface into the low frequence sub band LL to restore the tamper region. Experimental results show the availability of the proposed algorithm. <s> BIB006 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> A fragile self-recovery watermarking scheme with simple and effective tamper detection capability is proposed in this paper. In conventional fragile watermark for tamper detection and recovery, the parity section of the watermark is used for tamper detection and the restoration section of the watermark is used for image recovery, separately. In addition, to provide second chance for block recovery in case one copy is destroyed, Lee and Lin proposed dual watermarking scheme in which two copies of restoration watermark are embedded. In the proposed new scheme, fragile watermark with one parity section and two restoration sections are embedded, too. In addition to the second chance for image restoration, the two restoration sections as well as the parity section are all used for tamper detection. Experimental results show that the tamper detection capability is superior to other techniques. <s> BIB007 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> This paper proposes a semi-fragile digital watermarking scheme for image tamper localization and self-recovery. Firstly, the authentication watermark is generated for tampered area localization. After that, for content recovery, the recovery watermark is calculated from high frequency band with redundancy free. Then, for the two type of watermarks, the DWT-based watermark embedding method makes our proposed scheme tolerable against friendly manipulations. Even some parts of the watermarked image are tampered and the corresponding embedded information are missing, we can still recover the image from the untouched area based on the localization results and compressive sensing. Moreover, the encryption algorithm based on chaotic function guarantees the safety of our two type of watermarks. Extensive experiments demonstrate the effectiveness of the proposed scheme, which is sensitive against malicious tamper and robust to some incidental manipulations (e.g. JPEG compression, slight noise addition, brightness/contract adjustment and format conversion). <s> BIB008 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <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> BIB009 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> Fragile watermarking is discovered for authentication and content integrity verification. This paper introduces a modified fragile watermarking technique for image recovery. Here we can detect as well as recovered the tampered image with its tampered region. This modified approach helps us to produce resistance on various attacks like birthday attack, college attack and quantization attacks. Using a non-sequential block chaining and randomized block chaining, which is created on the basis of secrete key this modified technique produces great amount of recovery from tampered regions. In this modified technique we put a watermark information and information of recovery of image block into the image block. These blocks are linked with next randomly generated block of image. In this modified process of block chaining to obtained first watermark image, modified technique uses original image and watermarked image. While to obtained self-embedded image we merge shuffled original image on original image so that we get final shuffled image. At last we merge first watermark image with shuffled image to produce final watermarked image. During recovery we follow reverse process of above to obtained original image from tampered image. By comparing block by block mean values of tampered blocks recovery of tampered blocks can be done. This modified technique can be used for color as well as gray scale images. The implementation shows that, the proposed modified technique can be used with promising result as an alternative approach to image recovery from tampered area effectively. <s> BIB010 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <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> BIB011 </s> A recent survey of self-embedding fragile watermarking scheme for image authentication with recovery capability <s> Watermark generation <s> With the popularity of network and the continuous development of multimedia technology, saving of network bandwidth and copyright protection of multimedia content have gradually attracted people’s attention. The fragile watermark for integrity authentication of image data and protection of copyright has become a hotspot. In the storage and transmission process, image data must be compressed to save network bandwidth. As a result, semi-fragile watermarking techniques, which can be used to distinguish common image processing operations from malicious tampering, are emerging. In this paper, semi-fragile watermarking algorithms for image authentication are surveyed. The basic principles and characteristics about semi-fragile watermarking algorithms are introduced, and several kinds of attack behaviors are also included. Aiming at several typical image-authentication algorithms, advantages and disadvantages are analyzed, and evaluation indexes of various algorithms are compared. Finally, we analyze the key points and difficulties in the study on semi-fragile watermarking algorithms, and the direction about future development is prospected. <s> BIB012
The watermark embedding phase occurs at the sender side. As mentioned earlier, the first step is the original image divided into non-overlapping blocks of size n × n. Then a block mapping method is used to generate a chaotic map. Next step is generating authentication data and the feature information as recovery data, both of them form watermark component. Singh BIB011 generated two authentication bits, which the first authentication bit algorithm is shown in Fig. 6 and the second algorithm is shown in Fig. 7 . Generation of the first authentication bit (A b1 ) was using most significant bit (MSB) value; in this method, it was using 5 bit MSB of 8 binary bits, while 3 bit LSB values for the insertion process was used. For the second authentication bit generation (A b2 ), this method used check bit as a part of bit authentication; it implemented a longitudinal redundancy check (LRC) and pixel mean values for each block. Figures 6 and 7 represent the block diagram of the A b1 and the A b2 generation process in a spatial domain, where block pixel nth, P n (i, j), n indicates the position of the pixel block, where Meanwhile, row and column values of P n (i, j) are symbolised by P r n ði; jÞ and P c n ði; jÞ respectively. Other authentication bit generation schemes are given by Chang BIB005 where authentication bit information is generated through the local binary pattern (LBP) operator of each block as shown in Fig. 8 . Where P c is the centre pixel value, P x is each neighbouring pixel value and S x is the sign of each neighbouring pixel. In addition, a hash function used by Kunhu [40] is considered as a content authentication bit information. In this scheme, they divide an image into B blocks non-overlapping. Therefore, 64 hexadecimal unique hash keys for each block by using SHA-256 were acquired and converted each hexadecimal digit into 4-bit binaries and converted them into (1 × 256) up to the information limit. Finally, all the shared blocks will generate B * 256-bit hash key information. The embedded watermark data for image recovery are calculated from the original DCT of the host image and contain no additional redundancy BIB001 BIB009 BIB008 BIB012 . If the part of the watermarked image is damaged, the watermark data in the area can still be retrieved. If the amount of extracted data is greater, it will be able to reconstruct the original coefficient in the tampered area according to the given constraint. Otherwise, they may use press-sensing techniques to extract coefficients by utilising smoothness in the DCT domain. In this way, all extracted watermark data contribute to content recovery BIB006 . The smaller the damaged area, the available watermark data will result in better quality recovered content. It also shows that in general, the proposed scheme is superior to the previous technique. In Wu's scheme BIB007 , the watermark component consists of watermark parity and two copies of the restoration watermark section. All watermarks are used for tamper detection. Therefore, with the same watermark load size, the tamper detection performance of the proposed scheme is better. The PSNR of the watermarked image is about 44 dB since only two LSB of each pixel are used for watermark insertion. Under general disruption, content disruption only and attack averages are constant, the probability of false acceptance (PFA), the probability of false rejection (PFR) and the probability of false detection (PFD) are close to zero for different tamper ratios from 0 to 80%. For collage attacks, the proposed new scheme is superior to Lee's scheme and He's method  . To improve the detection process of damaged image areas, Dhole BIB010 uses DCT transfers to obtain the information data used for the recovery process. Then, the watermark is inserted into the original image to get the first watermark image. In the next step, the original image blocks are scrambled and combined in reversed order from the previous block to the original image to get the watermarked image. Then, they perform an Ex-OR operation to get a watermarked image. If the image starts to be damaged, modifications to the watermarked image can also be identified in the self-embedded image. They can find a modified image by doing inverse DCT. It is concluded from the survey that the existing methods for tamper detection and recovery require a lot of authentication and recovery data to be embedded. Generally, in self-embedding fragile watermarking, payload watermarks range from 1 to 3 bpp. With an increase in watermark payload, the PSNR value of the watermarked image will rise gradually  as described in Eq. (6) and (7) and Table 1 . This significantly reduces the quality of watermarked image perceptions. Furthermore, localisation in tamper detection and recovery is not handled efficiently in existing works. The existing method also does not validate detection and tamper recovery against some insertion, deletion and attack updates. In the study BIB002 , a fragile watermarking scheme is proposed to efficiently detect tamper information and restore damaged information. The scheme in BIB002 focuses on achieving higher quality regional recovery. In addition, improved authentication processes with higher accuracy on tamper detection are also focused on this method. For the evaluation of self-embedding watermarking techniques, performance metrics such as imperceptibility (PSNR) and embedding capacity (bpp) are used. To investigate the performance of tamper detection algorithms, as mentioned in Section 5, we use PFR, PFA and PFD as the quantitative performance measures BIB003 . In terms of PSNR BIB004 , this measures the quality of the watermarked images and the recovered images. PSNR is computed as Eq.  . Where Here, X and Y represent the watermarked image and recovered image respectively and Max I is the maximum possible pixel value of the image. Generally, in the self-embedding fragile watermarking, the watermark payload ranges from 1 to 3 bpp. The quality of the watermarked image is indicated by the increase of the PSNR value, to reduce distortion caused by watermark insertion can be done by replacing the LSB value and keeping the remaining MSB value. In BIB003 , supposed the original data in the LSB field is a uniform distribution, the average energy distortion emitted by the embedding watermark bit, α, is Eq. (6)  Then, the approximate PSNR value of the watermarked image with respect to the original one is Eq. (7) PSNR ≈ 10 log 10 255 In terms of PFA, PFR and PFD defined, respectively, as Eq. (8), (9) and (10) Where N is the blocks number, N t is the number of actual blocks, N td is the number of tampered blocks which are correctly detected and N ab is the number of authentic blocks which are falsely detected.