An improved tamper detection and localization scheme for volumetric DICOM images

Abstract

The development of teleradiology brings the convenience of global medical record access along with the concerns over the security of medical images transmitted over the open network. With the prevailing adoption of three-dimensional (3-D) imaging modalities, it is vital to develop a security mechanism to provide large volumes of medical images with privacy and reliability. This paper presents the development of a new and improved method of implementing tamper detection and localization based on a fully reversible digital watermarking scheme for the protection of volumetric DICOM images. This tamper detection and localization method utilizes the 3-D property of volumetric data to achieve much faster processing time at both sender and receiver sides without compromising tamper localization accuracy. The performance of the proposed scheme was evaluated by using sample volumetric DICOM images. Results show that the scheme achieved on average about 65 % and 72 % reduction in watermarking and dewatermarking processing time, respectively. For cases where the images had been tampered, it is possible to detect and localize the tampered areas with improved localization resolution in the images using the scheme.

Fig. 1

The watermarking flowchart

Fig. 2

The dewatermarking flowchart

Fig. 3

The integrity embedding structure

Fig. 4

Screenshots of example results of a successful watermarking using MRI heart dataset and b successful dewatermarking using the same dataset. The right image of (a) and the left image of (b) are the same

Fig. 5

Screenshot of sample result of successful tamper detection and localization with the tampered slices 1, 2, 5, and 8 enlarged. Tampered regions are highlighted with the red boxes

Fig. 6

Sample systematic testing results. Slices 1, 2, 5, and 8 of the MRI heart image set with tamper being localized using the new method. The red box in the image indicates where tamper has occurred

Fig. 7

a Slice 1 of the MRI heart image set with tamper being localized using the 2-D method; each red box has the size of 18 by 18 pixels. b Slice 1 of the MRI heart image set with tamper being localized using the new method; each red box has the size of 9 by 9 pixels

Fig. 8

Real case tamper localization results. a Watermarked slices 13 and 14 of the knee MR image set; b watermarked slices 13 and 14 of the same set with tamper present; c slices 13 and 14 with tamper being localized using the new method

Fig. 9

a Slice 14 of the knee MR image set with tamper being localized using the 2-D method; each red box has the size of 18 by 18 pixels; b slice 14 of the knee MR image set with tamper being localized using the new method; each red box has the size of 9 by 9 pixels