A Color Image Authentication Scheme With Grayscale Invariance

Color image authentication is a method that allows the detection of tampered regions on images. Existing related works evaluated their performance based visual quality and capability marked image, but issue grayscale invariance was ignored. However, many applications in processing required color to first convert into before any further post-processing such as edge detection, masking Photoshop, display e-ink. If resulting original are different value, they might produce outcomes after post-processing. Therefore, how maintain unchanged value has become an important issue. This paper presents grayscale-invariance technique. We proposed embed code two three primary channels adjust remaining one remedy distortion value. The experimental results showed that, when embedding each four-bit channels, images achieved average 33.26 dB peak signal-to-noise ratio (PSNR) while providing satisfactory detectability.