Transparent information hiding with automatic embedding range selection for ownership verification

This paper presents a transparent robust information hiding technique with automatic selection of embedding range. The discrete cosine transform (DCT) coefficients of grayscale watermark adaptively replace the DCT coefficient of original image within the selected embedding range. The embedding range is selected by investigating the perceptual quality of the watermarked image and the robustness of the embedded watermark. The proposed scheme successfully compromises the trade-off between the imperceptibility and robustness. Comparing to Tsai´s random replacement embedding scheme, our method can achieve higher robustness against attacks, while retaining better perceptual quality of the marked image. Moreover, the use of an image-dependent dual-key containing embedding locations and scaling factors, can enhance the security level of this scheme in ownership verification.