Patent US5815291A successfully refreshed from Google Patents.
US5815291A
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Image reading apparatus
Assignee: Canon Inc
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Filing: 1995-11-13
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Granted: 1998-09-29
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Expires: 2015-11-13
Abstract
Abstract An image reading apparatus measures, color by color, an average transmission-density signal based upon image information obtained from a color original through which light is transmitted, converts the measured average transmission-density signal of every color into a subject-lightness signal of every color, and effects a conversion into a reference color stimulus signal, which is indicated by the apex of a triangle substantially circumscribed by a spectrum locus of a predetermined chromaticity diagram, based upon the converted subject-lightness signal of every color.
Inventors
- 👤 Seita Shono
- 👤 Akihiro Usami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:35
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/603
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
91 words
An image reading apparatus comprising: reading means for generating image information representing a transparent original by illuminating the transparent original with light; and converting means for converting the image information to color signal data, wherein the color signal data is repressed by a combination of three stimulus data corresponding to vertices of a triangle which substantially contacts a spectrum locus of an xy chromaticity diagram at wavelengths of about 505 nm and 525 nm, and substantially overlaps the locus of a purple boundary formed by connecting 380 nm and 780 nm.
Claim 2
Dependent Claim
91 words
An image reading apparatus comprising: reading means for generating image information representing a transparent original by illuminating the transparent original with light; and converting means for converting the image information to color signal data, wherein the color signal data is repressed by a combination of three stimulus data corresponding to vertices of a triangle which substantially contacts a spectrum locus of an xy chromaticity diagram at wavelengths of about 505 nm and 525 nm, and substantially overlaps the locus of a purple boundary formed by connecting 380 nm and 780 nm.
Claim 3
Dependent Claim
18 words
The apparatus according to claim 1, wherein said converting means converts the image information using a look-up table.
Claim 4
Dependent Claim
16 words
The apparatus according to claim 1, wherein the original is an image formed on a film.
Claim 5
Dependent Claim
27 words
The apparatus according to claim 1, wherein said three stimulus positions on the xy coordinates are as follows: R: (0.734, 0.265) G: (-0.086, 1.086) B: (0.095, -0.031).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-09-28 | 2002-03-30 | 2002-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-28 | 2006-03-30 | 2006-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-28 | 2010-03-30 | 2010-09-29 | $7700.00 | Window Closed / Lapsed |