US5050223A
Expired / Lapsed
US
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Method of and apparatus for processing image signal
Assignee: Fujifilm Holdings Corp
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Filing: 1989-10-18
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Granted: 1991-09-17
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Expires: 2009-10-18
Abstract
Abstract A new image (S'ij) is generated from an image signal (Sij) by determining whether the configuration of the distribution of the image signal (Sij) at a point of interest (i, j) is upwardly convex, or a downwardly convex, or otherwise, employing, as the new image signal (S'ij), the original image signal (Sij) at the point of interest (i, j) if the configuration is upwardly convex or downwardly convex, and employing, as the new image signal (S'ij), an unsharp signal (Uij) if the configuration is otherwise. A differential signal (Sij-Uij), or an absolute signal |Sij Uij|, or a square signal ((Sij-Uij) 2 ), or a Laplacian signal (∇ 2 Sij) is compared with a threshold signal (T) to determine whether the configuration of the distribution of the image signal (Sij) at a point of interest (i, j) is upwardly convex, or a downwardly convex, or otherwise. The unsharp signal (Uij) comprises an average signal (Uaveij) or a median signal (Umedij) in a region including the point of interest (i, j). A sharpness emphasizing signal (S*ij) is calculated from the new image signal (S'ij) and the unsharp signal (Uij) according to the equation: S*ij=S'ij+K(S'ij-Uij) where K is a coefficient signal.
Inventors
- 👤 Katsuto Sumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:57
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4092
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
139 words
A method of processing an image signal in an image scanning apparatus by generating a new image signal (S' ij ) from an image signal (S ij ), comprising the steps of: generating an unsharp signal (U ij ) based on the image signal (Sij), determining whether the configuration of the distributrrion of the image signal (S ij ) at a point of interest (i,j) is upwardly convex, or downwardly convex, or otherwise based on the image signal (S ij ) and the unsharp signal (U ij ); employing, as the new image (S' ij ), the original image signal (S ij ) at the point of interest (i,j) if the configuration is upwardly convex or downwardly convex; and employing, as the new image signal (S' ij ), the unsharp signal (U ij ) if the configuration is otherwise.
Claim 2
Independent Claim
139 words
A method of processing an image signal in an image scanning apparatus by generating a new image signal (S' ij ) from an image signal (S ij ), comprising the steps of: generating an unsharp signal (U ij ) based on the image signal (Sij), determining whether the configuration of the distributrrion of the image signal (S ij ) at a point of interest (i,j) is upwardly convex, or downwardly convex, or otherwise based on the image signal (S ij ) and the unsharp signal (U ij ); employing, as the new image (S' ij ), the original image signal (S ij ) at the point of interest (i,j) if the configuration is upwardly convex or downwardly convex; and employing, as the new image signal (S' ij ), the unsharp signal (U ij ) if the configuration is otherwise.
Claim 3
Dependent Claim
62 words
A method according to claim 1, furether comprising the step of comparing a differential signal (Sij-Uij) produced by subtracting the unsharp signal (Uij) from the image signal (Sij) with a threshold signal (T) to determine whether the configuration of the distribution of the image signal (Sij) at a point of interest (i, j) is upwardly convex, or a downwardly convex, or otherwise.
Claim 4
Dependent Claim
67 words
A method according to claim 1, further comprising the step of comparing the absolute value |Sij-Uij| of a differential signal (Sij-Uij) produced by subtracting the unsharp signal (Uij) from the image signal (Sij) with a threshold signal (T) to determine whether the configuration of the distribution of the image signal (Sij) at a point of interest (i, j) is upwardly convex, or a downwardly convex, or otherwise.
Claim 5
Dependent Claim
31 words
A method according to claim 1, wherein said unsharp signal (Uij) comprises an average signal (Uaveij) or a median signal (Umedij) in a region including the point of interest (i, j).
Claim 6
Dependent Claim
31 words
A method according to claim 2, wherein said unsharp signal (Uij) comprises an average signal (Uaveij) or a median signal (Umedij) in a region including the point of interest (i, j).
Claim 7
Dependent Claim
31 words
A method according to claim 3, wherein said unsharp signal (Uij) comprises an average signal (Uaveij) or a median signal (Umedij) in a region including the point of interest (i, j).
Claim 8
Independent Claim
44 words
A method according to any one of claims 1 through 6, further comprising the step of calculating a sharpness emphasizing signal (S*ij) from the new image signal (S'ij) and the unsharp signal (Uij) according to the equation: S*ij=S'ij+K(S'ij-Uij) where K is a coefficient signal.
Claim 9
Independent Claim
89 words
An apparatus for processing an image signal, comprising: unsharp signal generating means for generating an unsharp signal (Uij) from an image signal (Sij); subtracting means for generating a differential signal (Sij-Uij) by subtracting said unsharp signal (Uij) from said image signal (Sij); comparing means for comparing said differential signal (Sij-Uij) with a predetermined constant (T); and new image signal selecting means for selecting either said image signal (Sij) or said unsharp signal (Uij) as a new image signal (S'ij) depending on the result of comparison by said comparing means.
Claim 10
Independent Claim
89 words
An apparatus for processing an image signal, comprising: unsharp signal generating means for generating an unsharp signal (Uij) from an image signal (Sij); subtracting means for generating a differential signal (Sij-Uij) by subtracting said unsharp signal (Uij) from said image signal (Sij); comparing means for comparing said differential signal (Sij-Uij) with a predetermined constant (T); and new image signal selecting means for selecting either said image signal (Sij) or said unsharp signal (Uij) as a new image signal (S'ij) depending on the result of comparison by said comparing means.
Claim 11
Independent Claim
108 words
An apparatus for processing an image signal, comprising: unsharp signal generating means for generating an unsharp signal (Uij) from an image signal (Sij); subtracting means for generating a differential signal (Sij-Uij) by subtracting said unsharp signal (Uij) from said image signal (Sij); absolute signal generating means for generating an absolute signal |Sij-Uij| indicating the absolute value of said differential signal (Sij-Uij); comparing means for comparing said absolute signal |Sij-Uij| with a predetermined constant (T); and new image signal selecting means for selecting either said image signal (Sij) or said unsharp signal (Uij) as a new image signal (S'ij) depending on the result of comparison by said comparing means.
Claim 12
Independent Claim
108 words
An apparatus for processing an image signal, comprising: unsharp signal generating means for generating an unsharp signal (Uij) from an image signal (Sij); subtracting means for generating a differential signal (Sij-Uij) by subtracting said unsharp signal (Uij) from said image signal (Sij); absolute signal generating means for generating an absolute signal |Sij-Uij| indicating the absolute value of said differential signal (Sij-Uij); comparing means for comparing said absolute signal |Sij-Uij| with a predetermined constant (T); and new image signal selecting means for selecting either said image signal (Sij) or said unsharp signal (Uij) as a new image signal (S'ij) depending on the result of comparison by said comparing means.
Claim 13
Dependent Claim
31 words
An apparatus according to claim 8, wherein said unsharp signal (Uij) comprises an average signal (Uaveij) or a median signal (Umedij) in a region including the point of interest (i, j).
Claim 14
Dependent Claim
31 words
An apparatus according to claim 9, wherein said unsharp signal (Uij) comprises an average signal (Uaveij) or a median signal (Umedij) in a region including the point of interest (i, j).
Claim 15
Independent Claim
50 words
An apparatus according to any one of claims 8 through 11, further comprising subtracting means, multiplying means, and adding means for jointly calculating a sharpness emphasizing signal (S*ij) from the new image signal (S'ij) and the unsharp signal (Uij) according to the equation: S*ij=S'ij+K(S'ij-Uij) where K is a coefficient signal.
References Cited (Backward Citations)
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