Minimization of image watermarking side effects through subjective optimization

TL;DR

This paper presents a semi-overlapped block optimization method for image watermarking that balances image quality and computational complexity by maximizing SSIM on DCT coefficients.

Contribution

It introduces a semi-overlapped block optimization approach that reduces computational complexity while maintaining high image quality in SSIM-based watermarking.

Findings

Semi-overlapped optimization reduces complexity to less than 8 times non-overlapped methods.

Maximizing SSIM improves image quality in watermarking.

Overlapped block optimization achieves higher quality at increased computational cost.

Abstract

This paper investigates the use of Structural Similaritys (SSIM) index on the minimized side effect to image watermarking. For fast implementation and more compatibility with the standard DCT based codecs, watermark insertion is carried out on the DCT coefficients and hence a SSIM model for DCT based watermarking is developed. For faster implementation, the SSIM index is maximized over independent 4x4 non-overlapped blocks but the disparity between the adjacent blocks reduces the overall image quality. This problem is resolved through optimization of overlapped blocks, but, the higher image quality is achieved at a cost of high computational complexity. To reduce the computational complexity while preserving the good quality, optimization of semi-overlapped blocks is introduced. We show that while SSIM-based optimization over overlapped blocks has as high as 64 times the complexity of the 4x4 non-overlapped method, with semi-overlapped optimization the high quality of overlapped method is preserved only at a cost of less than 8 times the non-overlapped method.