Reversible Watermarking dengan Metode Modifikasi Histogram pada Difference Image
Abstract: Reversible
watermarking schemes are widely used to maintain the authenticity of the
digital image. This research will discuss a method on histogram modification of
difference image in which the difference image is created from the difference
value of adjacent pixels of the image grayscale.
Embedding process begins by dividing the host image and watermark into b
blocks, followed by making a difference image of the host image block. From the
difference image histogram, determine the peak value, and modify the histogram
based on the peak value. Then, insert each block of the watermark to the
difference image that has been modified and transform back into the grayscale
image.
Extraction and recovery process is the inverted version of the embedding
stage. This process begins by dividing the watermarked image into b blocks,
followed by making a difference image of each block. Then, extract the data and
shift difference image histogram using a peak value. That difference image is
transformed back into a grayscale image.
Experimental results demonstrate that the average insertion capacity is
14% greater than Xue's with PSNR value over 48 dB for 4 x 4 pixels and 23 %
greater with PSNR over 46 dB for 8 x 8 pixels. From the comparison of
robustness to line and salt n’ pepper on the density of 0.05 noises is obtained
that the watermark with ECC is more robust than a watermark without ECC. JPEG
compression in lossless mode may be applied to the watermarked image. Multiple
insertion of watermark can be done with the consequence that the more
insertions will result in lower PSNR values.
Penulis: Yustina Retno, Agus
Harjoko
Kode Jurnal: jptinformatikadd110163
