EP0921675A2
Expired / Lapsed
EP
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Method of processing image information and method of preventing forgery of certificates or the like
Assignee: Toshiba Corp
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Filing: 1998-11-18
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Granted: —
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Expires: 2018-11-18
Abstract
Abstract Additional information, composed of characters, images, voice, etc., is converted into two-dimensional codes (step S104) and then converted into a visible additional image to be embedded (step S105). The additional image is embedded in a full-color main image in a state of invisibility to produce a composite image (step S106). The composite image is recorded on a non-electronic medium such as paper or on an electronic medium, such as a memory on a personal computer, over the Internet (step S108). The embedded additional image is extracted from the composite image recorded on the recording medium and the additional information is reproduced (steps S109, S113).
Inventors
- 👤 Takashi Toshiba Kabushiki Kaisha Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:18
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/0028; H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32203; H04N1/32208; H04N1/32251; H04N1/32288; H04N1/32304; H04N1/32309; G06T2201/00; G06T2201/005; G06T2201/0051; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3261; H04N2201/3269; H04N2201/327; H04N2201/3271; H04N2201/3274; H04N2201/3278
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
80 words
An image processing method characterized by
comprising the steps of: converting predetermined additional information
into a visible additional image to be embedded in
a main image (step S106); creating a composite image by embedding the
additional image in the main image in a state of
invisibility (steps S106); recording the composite image on a recording
medium (steps S108, S111); and extracting the embedded additional image from the
composite image recorded on the recording medium to
recover the predetermined information (S110).
Claim 2
Dependent Claim
27 words
The method according to claim 1, characterized
in that the conversion step includes a substep of
converting the additional information into visible
two-valued two-dimensional codes (step S104).
Claim 3
Dependent Claim
65 words
The method according to claim 1, characterized
in that the conversion step includes a substep of
converting the additional information into visible two-valued
two-dimensional codes (step S103) and a substep
of modulating the two-dimensional codes using predetermined
mask pattern information (step S302), and the
reproduction step includes a substep of extracting the
additional image from the composite image using the
mask pattern information (step S113).
Claim 4
Dependent Claim
49 words
The method according to claim 1, characterized
in that the conversion step includes a substep of
converting the additional information into visible
two-valued two-dimensional codes (step S104), a substep
of smoothing the two-dimensional codes (FIG. 9), and
a substep of modulating the two-dimensional codes with
predetermined mask pattern information.
Claim 5
Dependent Claim
84 words
The method according to claim 1, characterized
in that the conversion step includes a substep of
converting the additional information into visible
two-valued two-dimensional codes (step S104), a
substep of modulating the two-dimensional codes using
predetermined mask pattern information, a substep of
converting the value of each pixel of the modulated
additional information into a positive or negative
color difference amount for each of R, G, and B
components to form three color difference modulated
images for R, G, and B components (FIG. 11).
Claim 6
Dependent Claim
42 words
The method according to claim 5, characterized
in that the color difference amount for the R component
is opposite in sign to those for the G and B components
in the same pixel position on the color difference
modulated images (FIG. 11).
Claim 7
Dependent Claim
36 words
The method according to claim 6, characterized
in that the creation step creates the composite image
by superimposing the three color difference modulated
images for the R, G, and B components on a full-color
main image.
Claim 8
Dependent Claim
63 words
The method according to claim 1, characterized
by further comprising a step of converting a full-color
main image into an achromatic image composed of R, G,
and B components, and wherein the creation step creates
the composite image in such a way that it looks black
and white to the human visual system and its respective
pixels is composed of multiple color components.
Claim 9
Dependent Claim
47 words
The method according to claim 7, characterized
in that, for pixels in a region where the additional
image exhibits a maximum or minimum level of brightness,
their color difference amounts are set smaller than
those of other pixels, thereby preventing overflow or
underflow of the composite image.
Claim 10
Dependent Claim
85 words
An image processing method characterized by
comprising the steps of: converting predetermined additional information
into a visible additional image to be embedded in
a main image; creating a composite image by embedding the
additional image in the main image in a state of
invisibility, the composite image is produced in such a
way that it looks a black and white image to the human
visual system and its respective pixel is composed of
multiple color components; and recording the composite image on a recording
medium.
References Cited (Backward Citations)
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