Combined Hashing/Watermarking Method for Image Authentication
In this paper we present a combined
hashing/watermarking method for image authentication. A robust
image hash, invariant to legitimate modifications, but fragile to
illegitimate modifications is generated from the local image
characteristics. To increase security of the system the watermark is
generated using the image hash as a key. Quantized Index
Modulation of DCT coefficients is used for watermark embedding.
Watermark detection is performed without use of the original image.
Experimental results demonstrate the effectiveness of the presented
method in terms of robustness and fragility.
authentication, blind watermarking, image hash,
Blind Low Frequency Watermarking Method
We present a low frequency watermarking method
adaptive to image content. The image content is analyzed and
properties of HVS are exploited to generate a visual mask of the
same size as the approximation image. Using this mask we embed the
watermark in the approximation image without degrading the image
quality. Watermark detection is performed without using the original
image. Experimental results show that the proposed watermarking
method is robust against most common image processing operations,
which can be easily implemented and usually do not degrade the
Blind, digital watermarking, low frequency, visualmask.