A Self-Recovery Fragile Image Watermarking with Variable Watermark Capacity

Abstract

Currently, the watermark capacity of most self-recovery fragile image watermarking schemes is fixed. That means for smooth regions and texture regions, the length of watermark information is always the same. However, it is impractical since more recovery information is needed for the recovery of texture regions. In this paper, a self-recovery fragile image watermarking with variable watermark capacity is proposed. Based on the characteristic of singular value decomposition (SVD), a new block classification method is introduced. The image blocks are classified into smooth blocks and texture blocks. For smooth blocks, the average pixel values are adopted as the recovery information to recover the tampered blocks, while for texture blocks, the quantized and coded DCT coefficients are adopted as the recovery information. After encrypted by binary pseudo-random sequence, the recovery watermark of each block is embedded into its mapping block. In the detection side, the three-level detection mechanism is applied to detect and locate the tampered regions. The experimental results prove that the proposed method achieves good tamper detection results, and the recovered image has better image quality than other self-recovery fragile watermarking methods.

A Novel Image Tamper Detection and Self-Recovery Algorithm Based on Watermarking and Chaotic System

“…The types of attacks include collage attacks and large general tampering. We also compared the performance with the existing block-based approach [1,2,5,9]. All simulation environments were MATLAB R2018b.…”

“…Thus, for the mapping sequence, the most significant thing is to ensure the existence of the recovery information under the condition of a large tampering ratio. In [1,9,12], the 1-D transform algorithm was used to build the blocks relationship mapping function. Although the sequence is random, the remainder of the elements in the same column are equal, and the performance in the face of column tampering is poor.…”

“…According to Section 3.2, R e and R e will satisfy Equations (8) and (9). Thus, if R e = R /8 × 8 and R e = R /8 × 8, set the block to be a valid block, otherwise set it as an invalid block.…”

“…The algorithms in the transform domain first map the image into the other domain, such as discrete wavelet transform(DWT) [5,7,8], discrete cosine transform(DCT) [9][10][11], and lifting wavelet transform(LWT) [6]. Due to characteristics of the transform domain, the authentication and recovery information are generated by coefficients of the transform domain.…”

Digital Image Watermarking Techniques: A Review

“…The scheme is not dependent on using external metadata. In [26], binary pseudo-random sequences were used to encrypt the watermark before embedding, enhancing the security of the watermarking algorithm. The security requirement can be applied in telemedicine, digital imaging, telecommunications, multimedia data, etc.…”