EP0323265A2
Expired / Lapsed
EP
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Method of processing color image and apparatus therefor
Assignee: Canon Inc
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Filing: 1988-12-29
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Granted: —
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Expires: 2008-12-29
Abstract
Abstract According to a method and apparatus for processing a color image, three primary color signals are input, and the input three primary color signals are processed to obtain three color reproduction signals and a black reproduction signal. In order to obtain the black reproduction signal, a value corresponding to a minimum value of the three primary color signals is obtained, and the value is transformed by a continuous function having a minimum peak, thereby defining a transformed value as the black reproduction signal.
Inventors
- 👤 Akio Suzuki
- 👤 Yoshihiro Takada
- 👤 Masami Izumizaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 01:19
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6016; H04N1/6022
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
80 words
A method of processing a color image, comprising: inputting three primary color signals; and processing said input three primary color signals to obtain three color reproduction signals and a black reproduction signal, wherein the step of obtaining said black reproduction signal includes the steps of: obtaining a value corresponding a minimum value of said three primary color signals; and transforming the value by a continuous function having a minimum peak, thereby defining a transformed value as said black reproduction signal.
Claim 2
Independent Claim
80 words
A method of processing a color image, comprising: inputting three primary color signals; and processing said input three primary color signals to obtain three color reproduction signals and a black reproduction signal, wherein the step of obtaining said black reproduction signal includes the steps of: obtaining a value corresponding a minimum value of said three primary color signals; and transforming the value by a continuous function having a minimum peak, thereby defining a transformed value as said black reproduction signal.
Claim 3
Dependent Claim
14 words
A method according to claim 1, wherein said continuous function is a quadratic function.
Claim 4
Dependent Claim
14 words
A method according to claim 1, wherein said continuous function is a cubic function.
Claim 5
Dependent Claim
35 words
A method according to claim 1, further comprising the step of multiplying the value corresponding to the minimum value with a predetermined coefficient during transformation by said continuous function, thereby obtaining said black reproduction signal.
Claim 6
Dependent Claim
17 words
A method according to claim 1, wherein said three primary signals are R, G, and B signals.
Claim 7
Dependent Claim
16 words
A method according to claim 1, wherein said continuous function is a function passing an origin.
Claim 8
Dependent Claim
17 words
A method according to claim 1, wherein said reproduction signals are those in an ink-jet recording system.
Claim 9
Dependent Claim
24 words
A method according to claim 1, wherein said reproduction signals are those in recording on a back-print film by using an ink-jet recording system.
Claim 10
Independent Claim
106 words
A method of processing a color image, comprising the steps of: obtaining a minimum value K₀ of input three color signals; obtaining function values f₁(K₀) and f₂(K₀) corresponding to said minimum value K₀; and subtracting the function value f₁(K₀) from said three color signals to obtain values as three color reproduction signals and defining the value f₂(K₀) as a black reproduction signal, wherein differential values df₁(K₀)/dK₀ and df₂(K₀)/dK₀ of said function values f₁(K₀) and f₂(K₀) linearly increase within ranges of 0 < f₁ ≦ G₁ and 0 < f₂ ≦ G₂ (0 < G₁ ≦ f 1MAX , and 0 < G₂ ≦ F 2MAX ).
Claim 11
Independent Claim
106 words
A method of processing a color image, comprising the steps of: obtaining a minimum value K₀ of input three color signals; obtaining function values f₁(K₀) and f₂(K₀) corresponding to said minimum value K₀; and subtracting the function value f₁(K₀) from said three color signals to obtain values as three color reproduction signals and defining the value f₂(K₀) as a black reproduction signal, wherein differential values df₁(K₀)/dK₀ and df₂(K₀)/dK₀ of said function values f₁(K₀) and f₂(K₀) linearly increase within ranges of 0 < f₁ ≦ G₁ and 0 < f₂ ≦ G₂ (0 < G₁ ≦ f 1MAX , and 0 < G₂ ≦ F 2MAX ).
Claim 12
Dependent Claim
19 words
A method according to claim 9, wherein said function values f₁(K₀) and f₂(K₀) are represented by quadratic functions, respectively.
Claim 13
Dependent Claim
19 words
A method according to claim 9, wherein said function values f₁(K₀) and f₂(K₀) are represented by cubic functions, respectively.
Claim 14
Dependent Claim
17 words
A method according to claim 9, wherein said three color signals are Y, M and C signals.
Claim 15
Dependent Claim
17 words
A method according to claim 9, wherein said reproduction signals are those in an ink-jet recording system.
Claim 16
Dependent Claim
24 words
A method according to claim 9, wherein said reproduction signals are those in recording on a back-print film by using an ink-jet recording system.
Claim 17
Independent Claim
62 words
An apparatus for processing a color image, comprising: a) means for generating three primary color signals; b) means for obtaining a minimum value of said three primary color signals; c) means for transforming said minimum value by a continuous function having a minimum peak; and d) means for defining a value transformed by said transforming means to be a black reproduction signal.
Claim 18
Independent Claim
62 words
An apparatus for processing a color image, comprising: a) means for generating three primary color signals; b) means for obtaining a minimum value of said three primary color signals; c) means for transforming said minimum value by a continuous function having a minimum peak; and d) means for defining a value transformed by said transforming means to be a black reproduction signal.
Claim 19
Dependent Claim
14 words
An apparatus according to claim 15, wherein said continuous function is a quadratic function.
Claim 20
Dependent Claim
14 words
An apparatus according to claim 15, wherein said continuous function is a cubic function.
Claim 21
Dependent Claim
21 words
An apparatus according to claim 15, further comprising: e) means for subtracting said transformed value from said three primary color signals.
Claim 22
Dependent Claim
16 words
An apparatus according to claim 15, wherein said apparatus reproduces the color image by ink-jet recording.
Claim 23
Dependent Claim
18 words
An apparatus according to claim 15, wherein said apparatus reproduces the color image by a serial scan system.
Claim 24
Dependent Claim
20 words
An apparatus according to claim 19, wherein said apparatus reproduces the color image on a back-print film by ink-jet recording.
Claim 25
Independent Claim
43 words
A method of processing a color image comprising processing a plurality of primary color signals to obtain a black reproduction signal by obtaining a value corresponding to a minimum value of said primary color signals and performing a transformation on said obtained value.
Claim 26
Independent Claim
43 words
A method of processing a color image comprising processing a plurality of primary color signals to obtain a black reproduction signal by obtaining a value corresponding to a minimum value of said primary color signals and performing a transformation on said obtained value.
Claim 27
Dependent Claim
14 words
A method according to claim 22, wherein said transformation is by a continuous function.
Claim 28
Dependent Claim
17 words
A method according to claim 22, wherein said transformation is by a function having a minimum peak.
Claim 29
Dependent Claim
50 words
Color image processing apparatus which comprises processing means for processing a plurality of primary color signals, said processing means being operable for producing a black signal by obtaining a value corresponding to a predetermined value of said primary color signals and transforming said obtained value to derive said black signal.
Claim 30
Dependent Claim
50 words
Color image processing apparatus which comprises processing means for processing a plurality of primary color signals, said processing means being operable for producing a black signal by obtaining a value corresponding to a predetermined value of said primary color signals and transforming said obtained value to derive said black signal.
References Cited (Backward Citations)
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