EP0332706A1
Expired / Lapsed
EP
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High speed image fault detecting method and apparatus
Assignee: NTT Inc
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Filing: 1988-08-09
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Granted: —
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Expires: 2008-08-09
Abstract
Abstract In inspecting the appearance of a printed picture, picture data corrected or free of defects is selected as a reference picture, for each picture element of which a table is formed of the same number of flags as the number of levels of a picture, and an index space is formed of the flags for all the picture elements. The reference pattern is produced by turning on the flags in the index space, and inspection and determination are effected by making reference to the flags in the index space one time per each picture element depending upon the attribute value of the picture that is inspected. The allowable range of inspection is set prior to the flag propagation processing that turns on the flag in the allowable range in the index space. Further, not being limited to two values of on and off, the flag may assume many values. It is further possible to reduce the X- and Y-sizes of index space or to reduce the level axis by compressing the index space relying upon the hierarchical expression of the flag utilizing the characteristics of picture data or by avoiding the one-to-one correspondence between the standard picture and the index space.
Inventors
- 👤 Katsuyuki Tanimizu
- 👤 Shinichi Meguro
- 👤 Akira Ishii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:12
CPC Classifications
G; G06; G06T; G06T7/00; G06T7/0002; G06T7/0004; G06T7/001; G06V; G06V10/00; G06V10/70; G06V10/74; G06V10/75; G06V10/751; G06T2207/00; G06T2207/30; G06T2207/30108; G06T2207/30144
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
115 words
A high-speed fault detecting method comprising the steps of: (a) preparing, for each pixel of a reference image, a table including flags in a number corresponding to the number of levels of the pixel; (b) turning on a flag corresponding to an actual level of the pixel and turning off other flags in each table; and (c) comparing a level value of each pixel of an image to be inspected with a table of a corresponding pixel prepared for the reference image, and if a flag corresponding to the level value of the pixel of the image to be inspected is turned on, determining that no fault is present in the image to be inspected.
Claim 2
Dependent Claim
115 words
A high-speed fault detecting method comprising the steps of: (a) preparing, for each pixel of a reference image, a table including flags in a number corresponding to the number of levels of the pixel; (b) turning on a flag corresponding to an actual level of the pixel and turning off other flags in each table; and (c) comparing a level value of each pixel of an image to be inspected with a table of a corresponding pixel prepared for the reference image, and if a flag corresponding to the level value of the pixel of the image to be inspected is turned on, determining that no fault is present in the image to be inspected.
Claim 3
Dependent Claim
153 words
A high-speed fault detecting method comprising the steps of: (a) preparing, for each pixel of a reference image, a table including flags in a number corresponding to the number of levels of the pixel; (b) turning on a flag corresponding to a level value of the pixel and flags corresponding to levels falling within an allowable range of a reference level of the pixel and turning off other flags in each table; (c) turning on flags corresponding to levels at adjacent coordinate points within a range corresponding to an allowable positional difference amount; and (d) comparing a level value of each pixel of an image to be inspected with a table of a corresponding pixel provided for the reference image, and if a flag corresponding to the level value of the pixel of the image to be inspected is turned on, determining that no fault is present in the image to be inspected.
Claim 4
Dependent Claim
153 words
A high-speed fault detecting method comprising the steps of: (a) preparing, for each pixel of a reference image, a table including flags in a number corresponding to the number of levels of the pixel; (b) turning on a flag corresponding to a level value of the pixel and flags corresponding to levels falling within an allowable range of a reference level of the pixel and turning off other flags in each table; (c) turning on flags corresponding to levels at adjacent coordinate points within a range corresponding to an allowable positional difference amount; and (d) comparing a level value of each pixel of an image to be inspected with a table of a corresponding pixel provided for the reference image, and if a flag corresponding to the level value of the pixel of the image to be inspected is turned on, determining that no fault is present in the image to be inspected.
Claim 5
Dependent Claim
44 words
A method according to claim 1 or 2, wherein if the reference image is a color image, a table for each color signal component is prepared for each pixel, said table for each color signal component being compared with the image to be inspected.
Claim 6
Dependent Claim
46 words
A method according to claim 1 or 2, wherein if the reference image is a color image, a multidimensional table including axes corresponding to the number of color signal components is prepared for each pixel, said multidimensional table being compared with the image to be inspected.
Claim 7
Dependent Claim
85 words
A method according to claim 1, 2, 3 or 4, wherein an N-dimensional table including N axes is divided by M n with respect to the nth dimensional axis to form M₁ x M₂ x ... x M n small multidimensional tables, if an ON flag is included in any of said small multidimensional tables, this small multidimensional table is further divided into smaller multidimensional tables, and if no ON flag is included in any of said small multidimensional tables, division is not performed thereafter.
Claim 8
Dependent Claim
19 words
A method according to claim 1, 2, 3, or 4, wherein a value of each flag is a numeral.
Claim 9
Dependent Claim
84 words
A method according to claim 6, wherein an N-dimensional table including N axes is divided by M n with respect to the nth dimensional axis to form M₁ x M₂ x ... x M n small multidimensional tables, if a flag having a value other than "0" is included in any of said small multidimensional tables, this small multidimensional table is further divided into smaller multidimensional tables, and if all of said small multidimensional tables have flags of "0", division is not performed thereafter.
Claim 10
Dependent Claim
44 words
A method according to claim 5 or 7, wherein comparison between a pixel level value of each pixel of the image to be inspected and each multidimensional table prepared for the reference image is sequentially performed from upper multidimensional tables to lower multidimensional tables.
Claim 11
Dependent Claim
26 words
A method according to claim 1, 2, 3, 4 or 6, wherein a single table is prepared for a plurality of pixels of the reference image.
Claim 12
Dependent Claim
30 words
A method according to claim 1, 2, 3, 4 or 6, wherein a flag is prepared for each of a plurality of levels of each pixel of the reference image.
Claim 13
Dependent Claim
134 words
A high-speed fault detecting apparatus comprising: (a) reading means for reading a reference image and an image to be inspected; (b) image memory units for storing the reference image and the image to be inspected, respectively; (c) an index table for storing index flags, and an allowable conditions memory unit for storing a variation allowable range of an image; (d) an index flag setting unit for forming a pattern as an ON flag equivalent to the reference image in said index table, and propagating said ON flag in said index table in accordance with the variation allowable amount; (e) referring means for comparing an image signal of the reference image with said index table; and (f) a fault determining unit for determining the presence/absence of a fault on the basis of a reference result.
Claim 14
Dependent Claim
134 words
A high-speed fault detecting apparatus comprising: (a) reading means for reading a reference image and an image to be inspected; (b) image memory units for storing the reference image and the image to be inspected, respectively; (c) an index table for storing index flags, and an allowable conditions memory unit for storing a variation allowable range of an image; (d) an index flag setting unit for forming a pattern as an ON flag equivalent to the reference image in said index table, and propagating said ON flag in said index table in accordance with the variation allowable amount; (e) referring means for comparing an image signal of the reference image with said index table; and (f) a fault determining unit for determining the presence/absence of a fault on the basis of a reference result.
Claim 15
Dependent Claim
29 words
An apparatus according to claim 11, further comprising: means for dividing said table; and flag inspecting means for checking whether a significant flag is present in divided small tables.
References Cited (Backward Citations)
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