Facsimile and static presentation processing – Natural color facsimile – Scanning
Reexamination Certificate
1997-05-28
2001-03-06
Lee, Cheukfan (Department: 2722)
Facsimile and static presentation processing
Natural color facsimile
Scanning
C358S512000, C358S509000
Reexamination Certificate
active
06198551
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading apparatus used for a facsimile apparatus, a scanner, or the like.
2. Related Background Art
As an image reading apparatus for reading an original image, there is an apparatus having three photoelectronic conversion device arrays formed on a sensor substrate, and color filters arranged above the photoelectric conversion device arrays to split light into three color components, i.e., red (R), green (G), and blue (B) light components. In such an image reading apparatus, three light components, i.e., R, G, and B light components of light reflected by an original are simultaneously received through a lens to accumulate charges on the sensors, and R, G, and B image signals are output.
However, since the photosensitivity of a sensor with a filter becomes lower as the wavelength is shorter, the output level of the B photoelectric conversion device array is much lower than that of the R or G photoelectric conversion device array, resulting in a degradation in S/N ratio. For this reason, a blue image cannot be properly read. For example, when a solid blue original is to be read and output from an output device such as a color BJ printer, the color balance of the image undesirably becomes nonuniform.
SUMMARY OF THE INVENTION
It is an object of the present invention to suppress variations in output levels of sensors and read a high-quality image. It is another object of the present invention to suppress variations in output levels depending on the sensitivities of sensors. It is still another object of the present invention to suppress variations in output levels depending on the reception wavelengths of sensors.
In order to achieve the above objects, according to an aspect of the present invention, there is provided an image reading apparatus comprising an image sensor in which a plurality of line sensors having different sensitivities are arrayed, and a lens array for forming an image of a target object on the image sensor, wherein a light amount in the lens array changes depending on an image formation position, and a line sensor having the lowest sensitivity among the plurality of line sensors is arranged at an image formation position where the light amount is maximum.
With this arrangement, variations in output levels depending on the sensitivities of sensors can be suppressed, and a high-quality image can be read.
According to another aspect of the present invention, there is provided an image reading apparatus comprising an image sensor in which a plurality of line sensors having different reception wavelengths are arrayed, and a lens array for forming an image of a target object on the image sensor, wherein a light amount in the lens array changes depending on an image formation position, and a line sensor having the shortest reception wavelength among the plurality of line sensors is arranged at an image formation position where the light amount is maximum.
With this arrangement, variations in output levels depending on the reception wavelengths of sensors can be suppressed, and a high-quality image can be read.
Other objects and features of the present invention will be apparent from the following specification and accompanying drawings.
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patent: 4972255 (1990-11-01), Suzuki et al.
patent: 4985760 (1991-01-01), Maeshima et al.
patent: 5055921 (1991-10-01), Usui
patent: 5153750 (1992-10-01), Hiroi
patent: 5173599 (1992-12-01), Setani
patent: 5489995 (1996-02-01), Iso et al.
patent: 5517329 (1996-05-01), Ishizuka
patent: 5555107 (1996-09-01), Funada
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Lee Cheukfan
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