Damage-free digital watermarking based image tampering detection and positioning method

Abstract

The invention discloses a detection and location method for image tampering based on no damage to digital watermarks in the image integrity authentication technical field. At first, an authentication area is selected from an image and is made a multi-layer division, then an authentication code of image data in each layer of subarea is calculated, the description information of the authentication area and the authentication information of each subarea are added into a watermark load to be embedded into the image by adopting a method which has area selectivity and has no damage to digital watermarks; when the tampering is detected and located, the description information of the authentication area is read form the watermark load, an authentication area is reconstructed on the restored image and is made a multi-layer division, an authentication code of the image data in each layer of subarea is calculated, the authentication code is compared with the authentication code of the corresponding subarea extracted from the watermark load to determine the tampered area. Any tampering in a non-embedding area in the invention has no effluence on the correct extraction of the watermark information.

Description

technical field [0001] The invention relates to a method in the technical field of image processing, in particular to an image tampering detection and location method based on a lossless digital watermark. Background technique [0002] Digital image data can be easily tampered with existing technical means, but it is difficult to judge whether an image has been tampered with simply relying on human eyes. Image integrity authentication and tamper detection are becoming more and more important. The traditional integrity authentication based on cryptography is carried out by calculating the authentication code of the data. The authentication code can be a hash function controlled by a key, that is, a message authentication code, or it can be a digital signature calculated by using an asymmetric encryption system for the hash function. Among them, the hash function is a function that maps an arbitrary long digital string into a shorter fixed-length output digital string. Util...

AI Technical Summary

Problems solved by technology

Its disadvantages are: since the distortion caused by embedding watermark comes from the two watermarking systems, the magnitude of watermark distortion is often relatively high, and the distortion caused by embedding watermark is difficult to limit outside the area of ​​interest

If this framework is applied to medical images and other fields, in order to ensure that the image data in the region of interest does not affect the accuracy of medical diagnosis due to the distortion caused by the embedded watermark, the extraction of watermark information and the restoration of the original image have to be carried out every time. , which brings great inconvenience to the practical application

Images