Qifei Zhou

To extend the scale limits within which a template watermark remains detectable, this paper proposes a template watermarking algorithm for remote sensing images based on a radial spectral barcode (RSB). The RSB is a new geometry of template watermark whose inner and outer boundaries are separated along the radial direction of the discrete Fourier transform magnitude spectrum. In the embedding stage, the spectrum is divided into angular slots, a synchronization sequence generated from the secret key and the watermark are assigned to alternate slots, and the magnitude within the radial interval of each slot is modulated according to its sign. In the detection stage, the angular profile of the received spectrum is computed under a set of geometric hypotheses, the synchronization sequence is located by circular correlation, and the watermark is read from the synchronized profile without correcting the image. The experimental results demonstrate that the proposed method extends the detectable scale interval well beyond that of the ring-template methods while retaining robustness against rotation, translation, cropping, affine transformation, map reprojection, and signal-processing attacks. It outperforms the comparative algorithms in robustness at an equal or higher PSNR, with a low false detection rate.

This study presents a ring template watermarking method utilizing semantic segmentation and elliptical fitting to address the inadequate resilience of digital watermarking techniques for remote sensing images against geometric attacks and affine transformations. The approach employs a convolutional neural network to determine the coverage position of the annular template watermark automatically. Subsequently, it applies the least squares approach to align with the relevant elliptic curve of the annular watermark, facilitating the restoration of the watermark template post-deformation due to an attack. Ultimately, it acquires the watermark information by analyzing the binarized image according to the coordinates. The experimental results indicate that, despite various geometric and affine modification attacks, the NC mean value of watermark extraction exceeds 0.83, and the PSNR value surpasses 35, thereby ensuring substantial invisibility and enhanced robustness. In addition, the methods presented in this paper provide useful references for imaging data in other fields.

To address the variability and complexity of attack types, this paper proposes a multi-instance zero-watermarking algorithm that goes beyond the conventional one-to-one watermarking approach. Inspired by the class-instance paradigm in object-oriented programming, this algorithm constructs multiple zero watermarks from a single vector geographic dataset to enhance resilience against diverse attacks. Normalization is applied to eliminate dimensional and deformation inconsistencies, ensuring robustness against non-uniform scaling attacks. Feature triangle construction and angle selection are further utilized to provide resistance to interpolation and compression attacks. Moreover, angular features confer robustness against translation, uniform scaling, and rotation attacks. Experimental results demonstrate the superior robustness of the proposed algorithm, with normalized correlation values consistently maintaining 1.00 across various attack scenarios. Compared with existing methods, the algorithm exhibits superior comprehensive robustness, effectively safeguarding the copyright of vector geographic data.

Symmetry-breaking in security mechanisms can create vulnerabilities which attackers may exploit to gain unauthorized access or cause data leakage, ultimately compromising the integrity and security of vector geographic data. How to achieve tamper localization remains a challenging task in the field of data authentication research. We propose a precise authentication watermarking algorithm for vector geographic data based on multiple sorting mechanisms. During the watermark embedding process, a sequence of points is initially extracted from the original data, followed by embedding watermarks into each coordinate point. The embedded watermark information consists of the self-identification and ordering information of each coordinate point. Ordering information is crucial for establishing relationships among points and enhancing tamper localization. During the authentication phase, the extracted watermark information is compared with the newly generated watermark information. Self-identification information is used to authenticate addition attacks, while ordering information is used to authenticate deletion attacks. Experimental results demonstrate that the proposed algorithm achieves high precision in detecting and localizing both addition and deletion attacks, significantly outperforming the comparison method.

Identifying template watermarks under severe geometric distortions is a significant scientific problem in the current watermarking research for remote sensing images. We propose a novel watermarking algorithm that integrates the ring-shaped template watermark with the multiscale local contrast measure (LCM) method. In the embedding stage, the ring-shaped template watermark is embedded into the discrete Fourier transform (DFT) magnitude coefficients, converting the watermark into small targets in the DFT domain. During the detection stage, the multiscale LCM, a classic infrared small target detection method, enhances these small targets and generates a contrast map. Peak detection is then performed on the contrast map to determine the radius of the template watermark. Finally, circular edge local binarization is applied to extract the watermark information. The proposed method enables synchronization recovery of watermarks under blind conditions. The experimental results demonstrate that the method possesses strong robustness against various geometric attacks such as rotation, scaling, translation, and cropping. It outperforms comparative algorithms in terms of robustness and also exhibits good imperceptibility.