Embed Watermark By Adding Message Pattern in C

Posted: April 1st, 2008 | Author: | Filed under: My Self | Tags: , , | 5 Comments »

Post ini adalah respon kepada post si Izel yang bertajuk “Embed Watermark By Adding Message Pattern in C

Assume that Blind Embedding Algorithm works only in grayscale images. Here we encode only one bit of information, thus m is either 1 or 0. This system employs a single reference pattern, wr, which is an array of pixel intensities with the same size as the cover image. This pattern might be predefined or it might be generated randomly based on a watermark key. The message pattern, wm (which encodes one-bit message, m), is equal to either wr or –wr, depending on whether m = 1 or m = 0 respectively. In the embedder, the message pattern, wm, is scaled by an input parameter,a, to yield the added pattern. The value a controls the trade-off between visibility and robustness of the watermark. Thus the blind embedding algorithm computes the following:

Wm = { wr if m = 1;

{ -wr if m = 0;

wa = α wm;

cw = co + wa

[Source: Izel]

Adeh… kesian aku tengok bebudak nie… code separuh separuh.. Meh aku bocorkan rahsia penuh code tersebut. Lepas nie setiap kali tutorial… aku nak korang ucap thanks kat aku tau sebab kita dah tak yah buat tutorial utk module-module yang lepas2 nie… Sila lah download source code nye