Tamper Detection and Restoring System for Medical Images Using Wavelet-based Reversible Data Embedding

Abstract

Over the past few years, the billows of the digital trends and the exploding growth of electronic networks, such as worldwide web, global mobility networks, etc., have drastically changed our daily lifestyle. In view of the widespread applications of digital images, medical images, which are produced by a wide variety of medical appliances, are stored in digital form gradually. These digital images are very easy to be modified imperceptively by malicious intruders for illegal purposes. The well-known adage that "seeing is believing" seems not always a changeless truth. Therefore, protecting images from being altered becomes an important issue. Based on the lossless data-embedding techniques, two detection and restoration systems are proposed to cope with forgery of medical images in this paper. One of them has the ability to recover the whole blocks of the image and the other enables to recover only a particular region where a physician will be interested in, with a better visual quality. Without the need of comparing with the original image, these systems have a great advantage of detecting and locating forged parts of the image with high possibility. And then it can also restore the counterfeited parts. Furthermore, once an image is announced authentic, the original image can be derived from the stego-image losslessly. The experimental results show that the restored version of a tampered image in the first method is extremely close to the original one. As to the second method, the region of interest selected by a physician can be recovered without any loss, when it is tampered.

Tamper Localization and Lossless Recovery Watermarking Scheme with ROI Segmentation and Multilevel Authentication

“…Chiang et al proposed a reversible tamper localization scheme with tampered region recovery capability [10]. Their scheme, based on a difference expansion scheme proposed by Tian, was modified to allow the watermark to be embedded into the transform domain by using the integer Haar wavelet transform [11].…”

“…Tampered blocks are recovered using the lossy compressed ROI. However, this scheme and others [9,10,13,14] have a common disadvantage since the tampered area can only be approximately recovered, for example in the form of average intensity or lossy compression. The recovered image is only approximately identical to the original image and due to its poor quality; it may not be used for diagnosis purposes.…”

An Improved Tamper Detection and Localization Scheme for Volumetric DICOM Images

“…The advantages of using watermarking include enabling authentication information such as the metadata to be embedded into the medical images as visually unperceivable watermark payload and providing continuous authenticity and integrity protection of the images beyond the point of internal network. A number of digital watermarking techniques for medical images have been reported [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. These watermarking techniques can be broadly categorized into non-reversible [3,4] and reversible watermarking [2,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] in the literature where reversible watermarking has been more widely implemented.…”

“…To achieve tamper detection, Chang et al calculated the average pixel value of each non-overlapping block and encoded the value by using a symmetric key cryptosystem. This information was then decrypted at the recipient end to check for tampering [15]. In addition to detecting tampered regions, Wu et al incorporated image information in their tamper detection method to enable tampered regions to be partially recovered [8].…”

Authentication and Data Hiding Using a Hybrid ROI-Based Watermarking Scheme for DICOM Images

“…Once the embedded content is read, the watermark can be removed from the image allowing retrieval of the original image. [14][15][16][17] The third class includes algorithms based on using classical watermarking methods while minimizing the distortion. In that category, the watermark replaces some image details such as the least significant bit (LSB) of the image or details lost after lossy image compression.…”