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Definitions: Telecommunications techniques in which a signal is transmitted in a bandwidth considerably greater than the frequency content of the original information. Frequency hopping, direct sequence spreading, time scrambling, and combinations of these techniques are forms of spread spectrum.

Understandably, artists have resorted to “watermarking” their images online to prevent others from stealing their work. While watermarking can be a great deterrent, it's not the same thing as a copyright, nor is it a substitute for officially obtaining copyright protection from the US Copyright Office.

Firstly, decide whether you'd like to use text or make a logo. You could simply use your name - some artists scan their own signature and use that as their watermark. You take time and care over your photos, so the ideal watermark should be minimal so as not to take any quality or focus away from the image.

Both steganography and digital watermarking employ steganographic techniques to embed data covertly in noisy signals. While steganography aims for imperceptibility to human senses, digital watermarking tries to control the robustness as top priority.

A watermark could be a logo, an image, or text, and it can be as subtle or prominent on a document or photo as you'd like. You may want your watermark to feature copyright information, an identifier like your name or logo, or status information, like “Draft," or “For Review."

One of the most secure techniques of audio watermarking is spread spectrum audio watermarking (SSW). In SSW, a narrow-band signal is transmitted over a much larger bandwidth such that the signal energy presented in any signal frequency is undetectable.

This method uses the frequency hopping spread spectrum in order to determine positions for watermark embedding in an original image, while the direct spread spectrum technique is used to provide robustness to the watermark signal. To embed the watermark signal, the selected bits are used to carry the watermark signal.

In watermarking techniques, a symbol of owner authenticity (watermark) is embedded into the host signal and, later, this watermark data can be extracted. The watermark data, which may be visible or invisible, can contain a single bit, a set of binary data, or a number of samples in the host signal [5].