US5530561A
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Method of and apparatus for binarizing image signal
Assignee: Fujifilm Holdings Corp
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Filing: 1995-03-24
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Granted: 1996-06-25
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Expires: 2015-03-24
Abstract
Abstract To obtain a binary gradation image from a continuous gradation image, a multi-valued image signal I(x,y) is compared with a threshold signal TH by a comparator to produce a binary image signal P(x,y), an error signal E(x,y) is determined from the binary image signal P(x,y) and the multi-valued image signal I(x,y), and the error signal E(x,y) is multiplied by an error diffusion coefficient W(k,l) to produce a diffusion error signals ΔE(x,y). A random number R(x,y) generated by a random number generator and a weighting coefficient f(I(x,y)) generated as a function of an image signal by a weighting coefficient generator are multiplied, and the product is added to the diffusion error signals ΔE(x,y). The sum is added to the multi-valued image signal I(x,y) thereby to produce a corrected multi-valued image signal I(x,y), which is then compared with the threshold signal TH by the comparator thereby generating a binary image signal P(x,y).
Inventors
- 👤 Osamu Shimazaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:28
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4051; H04N1/4052; G; G06; G06V; G06V10/00; G06V10/20; G06V10/28; H04N1/4053
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
174 words
An apparatus for producing a binary gradation image signal from a continuous gradation image signal, comprising: a comparing means for comparing a multi-value image signal corresponding to a target pixel with a threshold signal to produce a binary image signal; an error calculating means for determining an error signal based on a difference between said multi-valued image signal and said binary image signal; an error diffusion means for determining a set of error diffusion signals based on said error signal and a set of error diffusion coefficients, and applying said error diffusion signals to pixels proximate to said target pixel; a random number generating means for generating a random number; a weighting coefficient generating means for generating a weighting coefficient whose value varies depending on a density value of an input multi-valued image signal; and a weighting means for multiplying said random number by said weighting coefficient; wherein the random number weighted by said weighting coefficient is applied to at least one of: said error signal, said error diffusion signals, and said threshold signal.
Claim 2
Independent Claim
174 words
An apparatus for producing a binary gradation image signal from a continuous gradation image signal, comprising: a comparing means for comparing a multi-value image signal corresponding to a target pixel with a threshold signal to produce a binary image signal; an error calculating means for determining an error signal based on a difference between said multi-valued image signal and said binary image signal; an error diffusion means for determining a set of error diffusion signals based on said error signal and a set of error diffusion coefficients, and applying said error diffusion signals to pixels proximate to said target pixel; a random number generating means for generating a random number; a weighting coefficient generating means for generating a weighting coefficient whose value varies depending on a density value of an input multi-valued image signal; and a weighting means for multiplying said random number by said weighting coefficient; wherein the random number weighted by said weighting coefficient is applied to at least one of: said error signal, said error diffusion signals, and said threshold signal.
Claim 3
Dependent Claim
21 words
An apparatus according to claim 1, further comprising: an adding means for adding the weighted random number to said error signal.
Claim 4
Dependent Claim
28 words
An apparatus according to claim 1, further comprising: a product summing means for producing the sum of products, between the error diffusion coefficients and the weighted random number.
Claim 5
Dependent Claim
25 words
An apparatus according to claim 1, further comprising: an adding means for adding the weighted random number to the result of said error diffusion process.
Claim 6
Dependent Claim
21 words
An apparatus according to claim 1, further comprising: an adding means for adding the weighted random number to said threshold signal.
Claim 7
Independent Claim
151 words
A method of producing a binary gradation image signal from a continuous gradation image signal, comprising the steps of: comparing a multi-valued image signal corresponding to a target pixel with a threshold signal to produce a binary image signal; determining an error signal based on a difference between said multi-valued image signal and said binary image signal; determining a set of error diffusion signals based on said error signal and a set of error diffusion coefficients; applying said error diffusion signals to pixels proximate said target pixel thereby to carry out an error diffusion process; generating a random number; generating a weighting coefficient whose value varies depending on a density value of an input multi-valued image signal; weighting said random number with said weighting coefficient; and applying the random number weighted by said weighting coefficient to at least one of said error signal, said error diffusion signals, and said threshold signal.
Claim 8
Independent Claim
151 words
A method of producing a binary gradation image signal from a continuous gradation image signal, comprising the steps of: comparing a multi-valued image signal corresponding to a target pixel with a threshold signal to produce a binary image signal; determining an error signal based on a difference between said multi-valued image signal and said binary image signal; determining a set of error diffusion signals based on said error signal and a set of error diffusion coefficients; applying said error diffusion signals to pixels proximate said target pixel thereby to carry out an error diffusion process; generating a random number; generating a weighting coefficient whose value varies depending on a density value of an input multi-valued image signal; weighting said random number with said weighting coefficient; and applying the random number weighted by said weighting coefficient to at least one of said error signal, said error diffusion signals, and said threshold signal.
Claim 9
Dependent Claim
20 words
A method according to claim 6, further comprising the step of adding the weighted random number to said error signal.
Claim 10
Dependent Claim
26 words
A method according to claim 6, further comprising the step of producing the sum of products between the error diffusion coefficients and the weighted random number.
Claim 11
Dependent Claim
24 words
A method according to claim 6, further comprising the step of adding the weighted random number to the result of said error diffusion process.
Claim 12
Dependent Claim
20 words
A method according to claim 6, further comprising the step of adding the weighted random number to said threshold signal.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1999-06-25 | 1999-12-25 | 2000-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-25 | 2003-12-25 | 2004-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-25 | 2007-12-25 | 2008-06-25 | $7700.00 | Window Closed / Lapsed |