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US 2003/0193700 A1Published application
Image reading apparatus and light source stability determination method
AssigneeNEC Corporation
InventorShinya Kubo
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AssigneeNEC Corporation
InventorShinya Kubo
Estimating the term…
A scanner has an imaging device which is constituted by a cold-cathode tube, includes a light source for irradiating light to a reflection surface of a reference white plate and a plurality of pixels arranged in one line, and detects light reflected on the reflection surface by the respective pixels, and has a light source stability determination unit which determines whether or not light amounts obtained by the one line of pixels from the light source are approximately uniform. Only in a case where the light source stability determination unit determines that the light amounts obtained by the one line of pixels from the light source are approximately uniform, the scanner reads the reference white plate to calculate correction values for the respective pixels and reads a manuscript.
A light source stability determination method applied to an image reading apparatus in which an imaging device formed by pixels arranged in one line detects light reflected on a white reflection surface having a uniform reflection ratio by the respective pixels, white correction values are calculated for the respective pixels based on amounts of the detected light, said imaging device detects light reflected on a manuscript by the respective pixels and generates first electric signals having signal levels corresponding to amounts of the detected light, and the signal levels of the first electric signals generated from the respective pixels are corrected by the correction values, said method comprising:
An image reading apparatus in which an imaging device formed by pixels arranged in one line detects light reflected on A white reflection surface having a uniform reflection ratio by the respective pixels, white correction values are calculated for the respective pixels based on amounts of the detected light, said imaging device detects light reflected on a manuscript by the respective pixels and generates first electric signals having signal levels corresponding to amounts of the detected light, and the signal levels of the first electric signals generated from the respective pixels are corrected by the correction values, said apparatus comprising:
Dependencies are inferred from the claim text.
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1. Field of the Invention
The present invention relates to an image reading apparatus and a light source stability determination method.
2. Description of the Related Art
These objects and other objects and advantages of the present invention will become more apparent upon reading of the following detailed description and the accompanying drawings in which:
FIG. 1 is a block diagram showing a structure of an image reading apparatus according to a first embodiment of the present invention;
FIG. 2 is a block diagram showing structures of a reading module and a scanner controller shown in FIG. 1;
An image reading apparatus and a light source stability determination method according to the embodiments of the present invention will now be explained with reference to the drawings, by employing a flat head type scanner which corrects the shading of a read image as an example.
(First Embodiment)
As shown in FIG. 1, a scanner 1 according to the first embodiment comprises a reading glass 2, a reference white plate 3, a reading module 4, a scanner controller 5, and a program memory 7.