Blind assessment of image quality employing fragile watermarking

The provision of blind quality assessment is an important requirement for modern multimedia and communication systems. Fragile watermarking techniques have been proposed earlier for this purpose. This paper proposes a novel approach which makes use of both fragile and robust watermarking techniques. The embedded fragile watermark is used to assess the degradation undergone by the transmitted images. Robust image features, on the other hand, are used to construct the reference watermark from the received image, for assessing the amount of degradation of the fragile watermark. Construction of the watermark from the image itself, dispenses with the need for embedding an extraneous watermark which must be made known to the user separately, a significant contribution of the present work in image quality assessment. Another contribution is the use of Singular Value Decomposition (SVD) for the extraction of the fragile watermark. The validity of the proposed approach is verified through extensive simulations using different kinds of gray-scale and color images.