A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Summary form only given, as follows. The author introduces data hiding in digital imagery as a new and powerful technology with applications including robust digital watermarking of images for copyright protection, image fingerprinting and authentication, tamper detection in digital imagery, covert (invisible) communication using images, access control, copy control in DVDs, embedding subtitles and audio tracks in video signals, etc. Data hiding is a highly multidisciplinary field that combines image and signal processing with cryptography, communication theory, coding theory, signal compression, and the theory of visual perception. <s> BIB001 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Because of the importance of the security issues in the management of medical information, we suggest the use of watermarking techniques to complete the existing measures for protecting medical images. We discuss the necessary requirements for such a system to be accepted by medical staff and its complementary role with respect with existing security systems. We present different scenarios, one devoted to the authentication and tracing of the images, the second to the integrity control of the patient's record. <s> BIB002 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> A data-hiding technique called the "bipolar multiple-number base" was developed to provide capabilities of authentication, integration, and confidentiality for an electronic patient record (EPR) transmitted among hospitals through the Internet. The proposed technique is capable of hiding those EPR related data such as diagnostic reports, electrocardiogram, and digital signatures from doctors or a hospital into a mark image. The mark image could be the mark of a hospital used to identify the origin of an EPR. Those digital signatures from doctors and a hospital could be applied for the EPR authentication. Thus, different types of medical data can be integrated into the same mark image. The confidentiality is ultimately achieved by decrypting the EPR related data and digital signatures with an exact copy of the original mark image. The experimental results validate the integrity and the invisibility of the hidden EPR related data. This newly developed technique allows all of the hidden data to be separated and restored perfectly by authorized users. <s> BIB003 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> This paper presents a mechanism and algorithm for creating undeniable watermarks. It assumes a system where a content owner or provider uses outside agents to distribute its content. Content watermarked by distribution agents using this system will be undeniably recognizable by the content provider as originating with that distribution agent. That is to say that given N distribution agents, the content provider will be able to tell which distribution agent watermarked the content. The system does not allow any distribution agent to watermark content that would appear to have been watermarked by another agent and it does also not allow the content provider to watermark content that would appear to have been watermarked by a particular distribution agent. This allows the content provider to place a high degree of trust in the identification of the distribution agent and trace "leak" locations of pirated copies of videos. <s> BIB004 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Abstract Medical images are currently created digitally and stored in the radiology department’s picture archiving and communication system. Reports are usually stored in the electronic patient record of other information systems, such as the radiology information system (RIS) and the hospital information system (HIS). But high-quality services can only be provided if electronic patient record data is integrated with digital images in picture archiving and communication systems. Clinicians should be able to access both systems’ data in an integrated and consistent way as part of their regular working environment, whether HIS or RIS. Also, this system should allow for teleconferencing with other users, eg, for consultation with a specialist in the radiology department. This article describes a web-based solution that integrates the digital images of picture archiving and communication systems with electronic patient record/HIS/RIS data and has built-in teleconferencing functionality. This integration has been successfully tested using three different commercial RIS and HIS products. <s> BIB005 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> We developed a Web-based system to interactively display image-based electronic patient records (EPR) for secured intranet and Internet collaborative medical applications. The system consists of four major components: EPR DICOM gateway (EPR-GW), image-based EPR repository server (EPR-Server), Web server and EPR DICOM viewer (EPR-Viewer). In the EPR-GW and EPR-Viewer, the security modules of digital signature and authentication are integrated to perform the security processing on the EPR data with integrity and authenticity. The privacy of EPR in data communication and exchanging is provided by SSL/TLS-based secure communication. This presentation gave a new approach to create and manage image-based EPR from actual patient records, and also presented a way to use Web technology and DICOM standard to build an open architecture for collaborative medical applications <s> BIB006 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Watermarking in medical images is a new area of research and some works in this area have been reported world wide recently. Most of the works are on the tamper detection of the images and embedding of the Electronics Patient Record (EPR) data in the medical images. Watermarked medical images can be used for transmission, storage or telediagnosis. Tamper detection watermarks are useful to locate the regions in the image where some manipulations have been made. EPR data hiding in images improves the confidentiality of the patient data, saves memory storage space and reduce the bandwidth requirement for transmission of images. This paper discusses various aspects of medical image watermarking and makes a review of various watermarking algorithms originally proposed for medical images. <s> BIB007 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Digital medical images are very easy to be modified for illegal purposes. For example, microcalcification in mammography is an important diagnostic clue, and it can be wiped off intentionally for insurance purposes or added intentionally into a normal mammography. In this paper, we proposed two methods to tamper detection and recovery for a medical image. A 1024 × 1024 x-ray mammogram was chosen to test the ability of tamper detection and recovery. At first, a medical image is divided into several blocks. For each block, an adaptive robust digital watermarking method combined with the modulo operation is used to hide both the authentication message and the recovery information. In the first method, each block is embedded with the authentication message and the recovery information of other blocks. Because the recovered block is too small and excessively compressed, the concept of region of interest (ROI) is introduced into the second method. If there are no tampered blocks, the original image can be obtained with only the stego image. When the ROI, such as microcalcification in mammography, is tampered with, an approximate image will be obtained from other blocks. From the experimental results, the proposed near-lossless method is proven to effectively detect a tampered medical image and recover the original ROI image. In this study, an adaptive robust digital watermarking method combined with the operation of modulo 256 was chosen to achieve information hiding and image authentication. With the proposal method, any random changes on the stego image will be detected in high probability. <s> BIB008 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Digital watermarking is a promising technology to embed information as unperceivable signals in digital contents. Various watermarking techniques have been proposed to protect copyrights of multimedia digital contents over Internet trading so that ownership of the contents can be determined in subsequent copyrights disputes. However, their applications in preventing unauthorized distribution of intelligence document have not been studied. In this paper, we propose a watermark-based document distribution protocol, which complements conventional cryptography-based access control schemes, to address the problem of tracing unauthorized distribution of sensitive intelligence documents. The reinforcement of document distribution policies requires a concrete support of non-repudiation in the distribution process. The distribution protocol is adapted from our previous work on the watermarking infrastructure for enterprise document management. It makes use of intelligence user certificates to embed the identity of the users into the intelligence documents to whom are distributed. In particular, keeping the identity secrecy between document providers and users (but yet traceable upon disputes) is a key contribution of this protocol in order to support for intelligence applications. We also outline an implementation of the distribution protocol and watermarking scheme employed. <s> BIB009 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> In this paper we introduce a highly efficient reversible data hiding technique. It is based on dividing the image into tiles and shifting the histograms of each image tile between its minimum and maximum frequency. Data are then inserted at the pixel level with the largest frequency to maximize data hiding capacity. It exploits the special properties of medical images, where the histogram of their non-overlapping image tiles mostly peak around some gray values and the rest of the spectrum is mainly empty. The zeros (or minima) and peaks (maxima) of the histograms of the image tiles are then relocated to embed the data. The grey values of some pixels are therefore modified. High capacity, high fidelity, reversibility and multiple data insertions are the key requirements of data hiding in medical images. We show how histograms of image tiles of medical images can be exploited to achieve these requirements. Compared with data hiding method in the whole image, our scheme can result in 30%–200% capacity improvement with still better image quality, depending on the medical image content. <s> BIB010 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Medical image is usually comprised of region of interest (ROI) and region of non interest (RONI). ROI is the region that contains the important information from diagnosis point of view so it must be stored without any distortion. We have proposed a digital watermarking technique which avoids the distortion of image in ROI by embedding the watermark information in RONI. The watermark is comprised of patient information, hospital logo and message authentication code, computed using hash function. Earlier BCH encryption of watermark is performed to ensure inaccessibility of embedded data to the adversaries. <s> BIB011 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> In this article, a new fragile, blind, high payload capacity, ROI (Region of Interest) preserving Medical image watermarking (MIW) technique in the spatial domain for gray scale medical images is proposed. We present a watermarking scheme that combines lossless data compression and encryption technique in application to medical images. The effectiveness of the proposed scheme, proven through experiments on various medical images through various image quality measure matrices such as PSNR, MSE and MSSIM enables us to argue that, the method will help to maintain Electronic Patient Report(EPR)/DICOM data privacy and medical image integrity. <s> BIB012 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Medical applications such as telediagnosis require information exchange over insecure networks. Therefore, protection of the integrity and confidentiality of the medical images is an important issue. Another issue is to store electronic patient record (EPR) in the medical image by steganographic or watermarking techniques. Studies reported in the literature deal with some of these issues but not all of them are satisfied in a single method. A medical image is distributed among a number of clinicians in telediagnosis and each one of them has all the information about the patient's medical condition. However, disclosing all the information about an important patient's medical condition to each of the clinicians is a security issue. This paper proposes a (k, n) secret sharing scheme which shares medical images among a health team of n clinicians such that at least k of them must gather to reveal the medical image to diagnose. Shamir's secret sharing scheme is used to address all of these security issues in one method. The proposed method can store longer EPR strings along with better authenticity and confidentiality properties while satisfying all the requirements as shown in the results. <s> BIB013 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> This paper proposes a reversible data hiding scheme for gray level images. It exploits the high correlation among image block pixels to produce a difference histogram. Secret data is embedded based on a multi-level histogram shifting mechanism with reference to the integer median of each block. The image blocks are divided into four categories due to four corresponding embedding strategies, aiming at preserving the medians during data embedding. In decoder, the median pixels are retrieved first followed by the hidden data extraction, and the host image can be accurately recovered via an inverse histogram shifting mechanism after removing the secret data from the marked image. Experimental results validate the effectiveness of our scheme and demonstrate that it outperforms several previous methods in terms of capacity and marked image's quality. <s> BIB014 </s> A Review of Medical Image Watermarking Requirements for Teleradiology <s> Advantages of Digital Watermarking <s> Medical Data Management (MDM) domain consists of various issues of medical information like authentication, security, privacy, retrieval and storage etc. Medical Image Watermarking (MIW) techniques have recently emerged as a leading technology to solve the problems associated with MDM. This paper proposes a blind, Contourlet Transform (CNT) based MIW scheme, robust to high JPEG and JPEG2000 compression and simultaneously capable of addressing a range of MDM issues like medical information security, content authentication, safe archiving and controlled access retrieval etc. It also provides a way for effective data communication along with automated medical personnel teaching. The original medical image is first decomposed by CNT. The Low pass subband is used to embed the watermark in such a way that enables the proposed method to extract the embedded watermark in a blind manner. Inverse CNT is then applied to get the watermarked image. Extensive experiments were carried out and the performance of the proposed scheme is evaluated through both subjective and quantitative measures. The experimental results and comparisons, confirm the effectiveness and efficiency of the proposed technique in the MDM paradigm. <s> BIB015
Watermarking has received much attention recently for medical image applications because of its various attractive attributes BIB002 BIB015 BIB007 , which are listed below: Security and Privacy The fundamental and most attractive property of watermarking is data-hiding capability BIB003 BIB010 . The utmost confidentiality can be maintained by hiding the private data into the images. Keeping necessary medical information (e.g., EPR including demographic data, diagnostic results, treatment procedures, etc.) hidden in medical images may provide a better security against malicious tampering, assuming medical images would not be of people's interest without the patient information BIB012 BIB013 . Even that which is tampered intentionally or in an unintended manner can be detected and possibly recovered by using an appropriate watermarking scheme BIB014 BIB008 . Hence, Coatrieux et al. BIB002 outlined three main objectives of watermarking in the medical image applications: data hiding, integrity control, and authenticity, which can provide the required security of medical images. For example, data-hiding objective of watermarking allows inserting meta-data and other information so that the image is more useful or easier to use. Integrity control objective of watermarking ascertains that the image has not been modified in an unauthorized manner. Digital watermarking allows permanent association of image content with proofs of its reliability by modifying [some] image pixel values, independently of the image file format BIB011 . It can also operate in a standalone environment and has a versatile message set. In addition, authenticity traces the origin of an image. Avoiding Detachment The data-hiding property of watermarking mentioned above further facilitates annotation of necessary information to avoid detachment. Millions of medical images are being produced in radiology departments around the world, which have immense value to practicing medical professionals, medical researchers, and students BIB015 . Researches in this field are being accomplished to embed patient data to medical images BIB003 BIB006 BIB005 . If the EPR and the images are separate, the chance of detachment of patient data from the image becomes higher. Misplacing a data will be very crucial in the case of medical image. In order to avoid this misplacing or detachment, watermarking offers necessary data embedding within the image itself. Indexing Another benefit stems from data-hiding capability of watermarking is indexing, where relevant keywords or indices can be embedded into the images and used for effective archiving and retrieval of the images from databases BIB015 . Nonrepudiation In teleradiology, distribution of the watermarked images between HISs may cause nonrepudiation problem, where both the involved parties (e.g., hospital personnel and clinician) may repudiate that they did not send the data. Along with other advantages, watermarking is also promising to support nonrepudiation in various multimedia applications BIB009 BIB004 . Hence, use of a key-based watermarking system may facilitate nonrepudiation in teleradiology such that both parties could be in safer side where the key used by the hospital could be their logos or digital signatures. Controlling Access Provision for using keys in watermarking schemes further provides an alternative to access control mechanism, where confidential meta-data can be accessed with the proper authoritative rights given in terms of keys BIB015 BIB001 . Memory and Bandwidth Saving Storage space and bandwidth requirements are important decisive factor for small hospitals' financial economy. The memory for storage can be saved to a certain extent in HIS by embedding the EPR in the image BIB005  . On the other hand, a huge amount of bandwidth is required for the transmission of the image data in teleradiology. The additional requirement of bandwidth for the transmission of the metadata can be avoided if the data is hidden in the image itself. Since the EPR and the image can be integrated into one, bandwidth for the transmission can be reduced in telemedicine applications BIB015 .