Image watermarking based on the space/spatial-frequency analysis and Hermite functions expansion

International audienceAn image watermarking scheme that combines Hermite functions expansion and space/spatial-frequency analysis is proposed. In the first step, the Hermite functions expansion is employed to select busy regions for watermark embedding. In the second step, the space/spatial-frequency representation and Hermite functions expansion are combined to design the imperceptible watermark, using the host local frequency content. The Hermite expansion has been done by using the fast Hermite projection method. Recursive realization of Hermite functions significantly speeds up the algorithms for regions selection and watermark design. The watermark detection is performed within the space/spatial-frequency domain. The detection performance is increased due to the high information redundancy in that domain in comparison with the space or frequency domains, respectively. The performance of the proposed procedure has been tested experimentally for different watermark strengths, i.e., for different values of the peak signal-to-noise ratio (PSNR). The proposed approach provides high detection performance even for high PSNR values. It offers a good compromise between detection performance (including the robustness to a wide variety of common attacks) and imperceptibility

A PARAMETRIC MULTICLASS BAYES ERROR ESTIMATOR FOR THE MULTISPECTRAL SCANNER SPATIAL MODEL PERFORMANCE EVALUATION.

Abstract not availabl

Watermarking of compressed multimedia using error-resilient VLCs

Abstract-Error-resilient variable length codes (VLCs) have been proposed to counter bit errors over error-prone channels. In this work we establish a linkage between channel coding and watermarking by observing that watermark bits are, in effect, intentional bit errors. Using a recently introduced resynchronizing VLC, we have developed a compressed-domain watermarking algorithm where the inherent errorresilient property of the code is exploited to implement lossless, oblivious watermarking. The algorithm is implemented on MPEG-2 video Keywords—watermarking, MPEG-2, error-resilient coding I

A Parametric Model for Multispectral Scanners

Efficient acquisition and utilization of remotely sensed data requires an extensive a priori evaluation of the performance of the basic data collection unit, the multispectral scanner. The objective is the development of a fully parametric technique to theoretically evaluate the systems response in any desired operational environment and provide the necessary information in selecting a set of optimum parameters. In this paper the multispectral scanner spatial characteristics are represented by a linear shift-invariant multiple-port system where the N spectral bands comprise the input processes. The scanner characteristic function, the relationship governing the transformation of the input spatial and hence spectral correlation matrices through the systems, is developed. Specific cases for Gaussian point spread functions are examined. The integration of the scanner spatial model and a parameter classification error estimator provides the necessary technique to evaluate the performance of a multispectral scanner. A set of test statistics are specified and the corresponding output quantities computed by the characteristic function. Two sets of classification accuracies, one at the input and one at the output are estimated. The scanner\u27s instantaneous field of view is changed and the variation of the output classification performance monitored