Patent EP0337325A2 successfully refreshed from Google Patents.
EP0337325A2
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Image processing method
Assignee: Yozan Inc
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Filing: 1989-04-07
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Granted: —
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Expires: 2009-04-07
Abstract
Abstract An image processing system for finding a local minimum in a histogram of an image in order to define a threshold comprising steps of; Generating a table of density according to the order of number of pixels; Assuming that the density of maximal number of pixels of the table is one local maximum of higher or lower density; Searching another local maximum and the local minimum based on the assumption; Assuming that the density of maximal number of pixels of the table is another local maximum of lower or higher density; Searching another local maximum and the local minimum based on the second assumption; and Determining true local maximums and the local minimum reviewing the first and second searching.
Inventors
- 👤 Ryohei C/O Ezel Inc. Kumagai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:37
CPC Classifications
G; G06; G06T; G06T7/00; G06T7/10; G06T7/11; G06T7/136; G06V; G06V10/00; G06V10/20; G06V10/28
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
119 words
An image processing system for finding a local minimum in a histogram of an image in order to define a threshold comprising steps of; Generating a table of density according to the order of number of pixels; Assuming that the density of maximal number of pixels of said table is one local maximum of higher or lower density; Searching another local maximum and said local minimum based on said assumption; Assuming that the density of maximal number of pixels of said table is another local maximum of lower or higher density; Searching another local maximum and said local minimum based on the second assumption; and Determining true local maximums and said local minimum reviewing said first and second searching.
Claim 2
Dependent Claim
119 words
An image processing system for finding a local minimum in a histogram of an image in order to define a threshold comprising steps of; Generating a table of density according to the order of number of pixels; Assuming that the density of maximal number of pixels of said table is one local maximum of higher or lower density; Searching another local maximum and said local minimum based on said assumption; Assuming that the density of maximal number of pixels of said table is another local maximum of lower or higher density; Searching another local maximum and said local minimum based on the second assumption; and Determining true local maximums and said local minimum reviewing said first and second searching.
Claim 3
Dependent Claim
74 words
An image processing method according to Claim 1, wherein, on searching said another local maximum and said local minimum, a number of pixels Nk in said table is successively assumed to be said number of pixels of said local minimum, and for each of said assumption of Nk a number of pixels Nl in said table is successively assumed to be said number of pixels of said local maximum under the condition that Nk<Nl.
Claim 4
Dependent Claim
69 words
An image processing method according to Claim 1, wherein, on searching said another local maximum and said local minimum, a number of pixels Nl in said table is successively assumed to be the number of pixels of said local maximum, and for each of said assumption of Nl, a number of pixels Nk in said table is successively assumed to be said number of pixels of said local minimum.
Claim 5
Dependent Claim
26 words
An image processing method according to Claim 2, wherein Nk is searched in predetermined direction from lower to higher density or from higher to lower density.
Claim 6
Dependent Claim
25 words
An image processing method according to Claim 3, wherein Nl is searched in predetermined direction from lower to higher or from higher to lower density.
Claim 7
Dependent Claim
70 words
An image processing method according to Claim 1, wherein said first and second searching are executed by evaluating the following calculation result. (N0-Nk)x(Nl-Nk) N0: Number of pixels of said density assumed to be one of local maximum first; Nl: Number of pixels of said density assumed to be another local maximum during said searching; Nk: Number of pixels of said density assumed to be said local minimum during said searching.
Claim 8
Dependent Claim
84 words
An image processing method according to Claim 6, wherein, for each Nk assumed, Nl is changed successively to the next Nl (Nl′ hereinafter) under the condition that; Dk>Dl′ and Nk<Nl′, as well as Dl>Dl′ and Nl<Nl′ Dl : Density having the number of pixels of Nl; Dl′: Density having the number of pixels of Nl′; Dk : Density having the number of pixels of Nk; Until the following condition occurs; (N0-Nk)x(Nl-Nk)<(N0-Nk)x(Nl′-Nk) , when N0 is assumed to be said local maximum of higher density.
Claim 9
Dependent Claim
58 words
An image processing method according to Claim 7, wherein Nk is changed successively to the next Nk (Nk′ hereinafter) under the condition that; Dk>Dk′ and Nk>Nk′ Dk : Density having the number of pixels of Nk; Dk′: Density having the number of pixels of Nk′. , when N0 is assumed to be said local maximum of higher density.
Claim 10
Dependent Claim
83 words
An image processing method according to Claim 6, wherein, for each assumed Nk, Nl is changed successively to the next Nl (Nl′ hereinafter) under the condition that; Dk>Dl and Nk<Nl′, as well as Dk<Dl′ and Nk<Nl′ Dl : Density having the number of pixels of Nl; Dl′: Density having the number of pixels of Nl′; Dk : Density having the number of pixels of Nk; Until the following condition occurs; (N0-Nk)x(Nl-Nk)<(N0-Nk)x(Nl′-Nk) ,when N0 is assumed to be said local maximum of higher density.
Claim 11
Dependent Claim
58 words
An image processing method according to Claim 7, wherein Nk is changed successively to the next Nk (Nk′ hereinafter) under the condition that; Dk<Dk′ and Nk>Nk′ Dk : Density having the number of pixels of Nk; Dk′: Density having the number of pixels of Nk′. , when N0 is assumed to be said local maximum of higher density.
Claim 12
Dependent Claim
66 words
An image processing method according to Claim 6, wherein, for each Nl assumed, Nk is changed successively to the next Nk (Nk′ hereinafter) under the condition that; Dk<Dl′ and Nk′>Nl, as well as Dk′<Dk and Nk′<Nk Dk: Density having the number of pixels of pixels of Nk; Dk′: Density having the number of pixels of Nk′; Dl : Density having the number of pixels of Nl.
Claim 13
Dependent Claim
11 words
An image method according to Claim 1, wherein histogram is flattened.
References Cited (Backward Citations)
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