watermark PicMarkr Pro

PicMarkr Pro Demo

Watermark images, protect your pictures copyright,
import and backup Flickr images to your computer
with PicMarkr Pro

Over 250,000 Flickr users have been using PicMarkr since 01/01/2008
Try PicMarkr Pro for MS Windows ®

Free Download PicMarkr Pro Order PicMarkr Pro

What is Digital watermarking?

Digital watermarking is the process of embedding information into a digital signal in a way that is difficult to remove. The signal may be audio, pictures or video, for example. If the signal is copied, then the information is also carried in the copy. A signal may carry several different watermarks at the same time.

In visible watermarking, the information is visible in the picture or video. Typically, the information is text or a logo which identifies the owner of the media. The image on the right has a visible watermark. When a television broadcaster adds its logo to the corner of transmitted video, this is also a visible watermark.

In invisible watermarking, information is added as digital data to audio, picture or video, but it cannot be perceived as such (although it may be possible to detect that some amount of information is hidden). The watermark may be intended for widespread use and is thus made easy to retrieve or it may be a form of Steganography, where a party communicates a secret message embedded in the digital signal. In either case, as in visible watermarking, the objective is to attach ownership or other descriptive information to the signal in a way that is difficult to remove. It is also possible to use hidden embedded information as a means of covert communication between individuals.

One application of watermarking is in copyright protection systems, which are intended to prevent or deter unauthorized copying of digital media. In this use a copy device retrieves the watermark from the signal before making a copy; the device makes a decision to copy or not depending on the contents of the watermark. Another application is in source tracing. A watermark is embedded into a digital signal at each point of distribution. If a copy of the work is found later, then the watermark can be retrieved from the copy and the source of the distribution is known. This technique has been reportedly used to detect the source of illegally copied movies.

Annotation of digital photographs with descriptive information is another application of invisible watermarking.

While some file formats for digital media can contain additional information called metadata, digital watermarking is distinct in that the data is carried in the signal itself.

The use of the word of watermarking is derived from the much older notion of placing a visible watermark on paper.

Digital Watermarking can be used for a wide range of applications such as:

Classification of Digital Watermarking

A digital watermark is called robust with respect to transformations if the embedded information can reliably be detected from the marked signal even if degraded by any number of transformations. Typical image degradations are JPEG compression, rotation, cropping, additive noise and quantization. For video content temporal modifications and MPEG compression are often added to this list. A watermark is called imperceptible if the cover signal and marked signal are indistinguishable with respect to an appropriate perceptual metric[clarification needed]. In general it is easy to create robust watermarks or imperceptible watermarks, but the creation of robust and imperceptible watermarks has proven to be quite challenging. Robust imperceptible watermarks have been proposed as tool for the protection of digital content, for example as an embedded 'no-copy-allowed' flag in professional video content.

Digital watermarking techniques can be classified in several ways.


Robustness

A watermark is called fragile if it fails to be detected after the slightest modification. Fragile watermarks are commonly used for tamper detection (integrity proof). Modifications to an original work that are clearly noticeable are commonly not referred to as watermarks, but as generalized barcodes.

A watermark is called semi-fragile if it resists benign transformations but fails detection after malignant transformations. Semi-fragile watermarks are commonly used to detect malignant transformations.

A watermark is called robust if it resists a designated class of transformations. Robust watermarks may be used in copy protection applications to carry copy and access control information.


Perceptibility

A watermark is called imperceptible if the original cover signal and the marked signal are (close to) perceptually indistinguishable.

A watermark is called perceptible if its presence in the marked signal is noticeable, but non-intrusive.

Capacity

The length of the embedded message determines two different main classes of watermarking schemes:

* The message is conceptually zero-bit long and the system is designed in order to detect the presence or the absence of the watermark in the marked object. This kind of watermarking schemes is usually referred to as Italic zero-bit or Italic presence watermarking schemes. Sometimes, this type of watermarking scheme is called 1-bit watermark, because a 1 denotes the presence (and a 0 the absence) of a watermark.
* The message is a n-bit-long stream (m=m_1\ldots m_n,\; n\in\N, with n = | m | ) or M = {0,1}n and is modulated in the watermark. This kinds of schemes are usually referred to as multiple bit watermarking or non zero-bit watermarking schemes.

Embedding method

A watermarking method is referred to as spread-spectrum if the marked signal is obtained by an additive modification. Spread-spectrum watermarks are known to be modestly robust, but also to have a low information capacity due to host interference.

A watermarking method is said to be of quantization type if the marked signal is obtained by quantization. Quantization watermarks suffer from low robustness, but have a high information capacity due to rejection of host interference.

A watermarking method is referred to as amplitude modulation if the marked signal is embedded by additive modification which is similar to spread spectrum method but is particularly embedded in the spatial domain.


Evaluation/benchmarking

The evaluation of digital watermarking schemes can provide detailed information for a watermark designer or for end users. Therefore, different evaluation strategies exist. Often used by a watermark designer is the evaluation of single properties to show, for example, an improvement. End users are mostly not interested in detailed information. They want to know if a given digital watermarking algorithm can be used for their application scenario, and if so, which parameter sets seems to be the best.
Secure digital camera

A secure digital camera (SDC) is proposed by Mohanty, et al. in 2003 which got published in January 2004 Blythe and Fridrich have also worked on SDC in 2004 for a digital camera that would use lossless watermarking to embed a biometric identifier together with a cryptographic hash.


Precursor cameras

Epson and Kodak have produced cameras with security features such as the Epson PhotoPC 3000Z and the Kodak DC-290. Both cameras added irremovable features to the pictures which distorted the original image, making them unacceptable for some applications such as forensic evidence in court. According to Blythe and Fridrich, "[n]either camera can provide an undisputable proof of the image origin or its author".
Reversible data hiding

Reversible data hiding is a technique which enables images to be authenticated and then restored to their original form by removing the watermark and replacing the image data which had been overwritten. This would make the images acceptable for legal purposes. The US army is also interested in this technique for authentication of reconnaissance images.

Order now or download PicMarkr Pro free trial

Samples & Screenshots

Take a product tour, view its key features
and check out the examples of product usage.
Learn how to watermark your photos easily!

Update: Video-tour added

Order Now

Just $39.99 USD for personal license
and free upgrades to all 1.xx versions.

Free Download Watermark Software

Download PicMarkr Pro and try all features for free! Explore the world of digital image watermarking without paying any cost.

Testimonials

"I bought it as soon as it was released. I've been a big fan of PicMarkr and now with the uploader it saves me a step from uploading to Flickr and then back down to PicMarkr and then back up to Flickr. I love it!"
by captjoe06 on Flickr

Mac user?

Subscribe to our Newsletter to get notified about PicMarkr Pro for Mac!
Thank you!
©copyright watermark software PicMarkr Pro, 2008.
Terms of Service | Privacy Policy | End User License Agreement