A agenda watermark is alleged able-bodied with account to transformations if the anchored advice may be detected anxiously from the apparent signal, alike if base by any cardinal of transformations. Typical angel degradations are JPEG compression, rotation, cropping, accretion noise, and quantization. For video content, banausic modifications and MPEG compression generally are added to this list. A agenda watermark is alleged ephemeral if the watermarked agreeable is perceptually agnate to the original, unwatermarked content.[1] In general, it is accessible to actualize able-bodied watermarks—or—imperceptible watermarks, but the conception of robust—and—imperceptible watermarks has accurate to be absolutely challenging.[2] Able-bodied ephemeral watermarks accept been proposed as apparatus for the aegis of agenda content, for archetype as an anchored no-copy-allowed banderole in able video content.[3]
Digital watermarking techniques may be classified in several ways.
Robustness
A agenda watermark is alleged brittle if it fails to be apparent afterwards the aboriginal modification. Brittle watermarks are frequently acclimated for alter apprehension (integrity proof). Modifications to an aboriginal assignment that acutely are noticeable, frequently are not referred to as watermarks, but as ambiguous barcodes.
A agenda watermark is alleged semi-fragile if it resists amiable transformations, but fails apprehension afterwards cancerous transformations. Semi-fragile watermarks frequently are acclimated to ascertain cancerous transformations.
A agenda watermark is alleged able-bodied if it resists a appointed chic of transformations. Able-bodied watermarks may be acclimated in archetype aegis applications to backpack archetype and no admission ascendancy information.
Perceptibility
A agenda watermark is alleged ephemeral if the aboriginal awning arresting and the apparent arresting are (close to) perceptually indistinguishable.
A agenda watermark is alleged apparent if its attendance in the apparent arresting is noticeable, but non-intrusive.
Capacity
The breadth of the anchored bulletin determines two altered capital classes of agenda watermarking schemes:
The bulletin is conceptually zero-bit continued and the arrangement is advised in adjustment to ascertain the attendance or the absence of the watermark in the apparent object. This affectionate of watermarking arrangement is usually referred to as zero-bit or attendance watermarking schemes. Sometimes, this blazon of watermarking arrangement is alleged 1-bit watermark, because a 1 denotes the attendance (and a 0 the absence) of a watermark.
The bulletin is a n-bit-long beck (m=m_1\ldots m_n,\; n\in\N, with n = | m | ) or M = {0,1}n and is articulate in the watermark. These kinds of schemes usually are referred to as multiple-bit watermarking or non-zero-bit watermarking schemes.
Embedding method
A agenda watermarking adjustment is referred to as spread-spectrum if the apparent arresting is acquired by an accretion modification. Spread-spectrum watermarks are accepted to be abundantly robust, but additionally to accept a low advice accommodation due to host interference.
A agenda watermarking adjustment is said to be of quantization blazon if the apparent arresting is acquired by quantization. Quantization watermarks ache from low robustness, but accept a aerial advice accommodation due to bounce of host interference.
A agenda watermarking adjustment is referred to as amplitude accentuation if the apparent arresting is anchored by accretion modification which is agnate to advance spectrum method, but is decidedly anchored in the spatial domain.
Digital watermarking techniques may be classified in several ways.
Robustness
A agenda watermark is alleged brittle if it fails to be apparent afterwards the aboriginal modification. Brittle watermarks are frequently acclimated for alter apprehension (integrity proof). Modifications to an aboriginal assignment that acutely are noticeable, frequently are not referred to as watermarks, but as ambiguous barcodes.
A agenda watermark is alleged semi-fragile if it resists amiable transformations, but fails apprehension afterwards cancerous transformations. Semi-fragile watermarks frequently are acclimated to ascertain cancerous transformations.
A agenda watermark is alleged able-bodied if it resists a appointed chic of transformations. Able-bodied watermarks may be acclimated in archetype aegis applications to backpack archetype and no admission ascendancy information.
Perceptibility
A agenda watermark is alleged ephemeral if the aboriginal awning arresting and the apparent arresting are (close to) perceptually indistinguishable.
A agenda watermark is alleged apparent if its attendance in the apparent arresting is noticeable, but non-intrusive.
Capacity
The breadth of the anchored bulletin determines two altered capital classes of agenda watermarking schemes:
The bulletin is conceptually zero-bit continued and the arrangement is advised in adjustment to ascertain the attendance or the absence of the watermark in the apparent object. This affectionate of watermarking arrangement is usually referred to as zero-bit or attendance watermarking schemes. Sometimes, this blazon of watermarking arrangement is alleged 1-bit watermark, because a 1 denotes the attendance (and a 0 the absence) of a watermark.
The bulletin is a n-bit-long beck (m=m_1\ldots m_n,\; n\in\N, with n = | m | ) or M = {0,1}n and is articulate in the watermark. These kinds of schemes usually are referred to as multiple-bit watermarking or non-zero-bit watermarking schemes.
Embedding method
A agenda watermarking adjustment is referred to as spread-spectrum if the apparent arresting is acquired by an accretion modification. Spread-spectrum watermarks are accepted to be abundantly robust, but additionally to accept a low advice accommodation due to host interference.
A agenda watermarking adjustment is said to be of quantization blazon if the apparent arresting is acquired by quantization. Quantization watermarks ache from low robustness, but accept a aerial advice accommodation due to bounce of host interference.
A agenda watermarking adjustment is referred to as amplitude accentuation if the apparent arresting is anchored by accretion modification which is agnate to advance spectrum method, but is decidedly anchored in the spatial domain.
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