Issues in Information Hiding Transform Techniques
Abstract
This paper gives a review of prevailing transform embedding techniques for information hiding, and discusses the robustness and detectability of two specific methods. Spatial embedding inserts messages into image pixels. Transform embedding embeds a message by modifying selected frequency coefficients of the cover image. Ideally, the message embedded with transform techniques is more robust to different image processing attacks and more transparent to human visual systems than that of spatial domain techniques. Transform embedding techniques that we are particularly interested in are the Discrete Fourier Transform (DFT), the Discrete Cosine Transform (DCT), and the Discrete Wavelet Transform (DWT). Detection of the hidden message and robust embedding are two of the principal objectives of our information hiding research. We show that a watermarked image that is perceptually invisible in the spatial domain may fail our detectability test. Our approach to detectability is based on DFT domain analysis Embedding a message under the least significant bits (LSB) of pixels (LSB embedding) is commonly used. We investigate ways to improve the robustness of LSB embedding and propose a method for protecting embedded data against two specific forms of filtering.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 20, 2002
- Accession Number
- ADA401948
Entities
People
- Liwu Chang
Organizations
- United States Naval Research Laboratory