Facsimile and static presentation processing – Natural color facsimile – Scanning
Reexamination Certificate
1998-12-04
2001-10-09
Lee, Cheukfan (Department: 2722)
Facsimile and static presentation processing
Natural color facsimile
Scanning
C358S510000
Reexamination Certificate
active
06301024
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading device by which an image signal, recorded in a recording medium, is sensed using a line sensor, for example.
2. Description of the Related Art
Conventionally, in an image reading device that senses the image by using an imaging device such as a line sensor, there are several ways to detect a focal position at which an image to be read is focused. For example, an image signal is read by the line sensor, and is subjected to a filtering process using a low pass filter, which passes signals derived when a focusing lens is not in an in-focus condition, so that a filtered image signal is obtained. The filtered image signal is subtracted from the original image signal, and the resultant image signal obtained by the subtraction is integrated, so that the contrast of the image is obtained. The focal position is detected in accordance with the contrast.
Thus, a complicated calculation is needed in the filtering process to detect the focal position. Further, when an image signal is processed, it should be taken into consideration that frequency characteristics of the image signal differ depending upon an object to be read. Furthermore, if the image signal contains noise, since the noise is integrated together with the image signal or a phase of light is inverted due to the limit of performance of the lens, the peak value of the contrast may not be calculated with a high accuracy.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an image reading device in which a complicated filtering process and an auto focusing control are not required, and which has a simple and miniaturized construction.
According to the present invention, there is provided an image reading device comprising a light source, an optical system, a line sensor, an out-of-register sensing processor and an out-of-register adjusting processor.
The light source radiates a plurality of light beams of differing color components. The optical system changes the plurality of light beams to a plurality of parallel beams, and leads the plurality of parallel beams to a recording medium. One of the plurality of parallel beams is parallel to an optical axis of the optical system. The remaining beam of the plurality of parallel beams is inclined to the optical axis. The line sensor senses the plurality of parallel beams passing through the recording medium, to generate at least first and second line image signals corresponding to an image recorded on the recording medium. The one of the plurality of parallel beams, which passes through a predetermined point on the recording medium, enters a first portion of a light receiving surface of the line sensor. The remaining beam of the plurality of parallel beams, which passes through the predetermined point, enters a second portion of the light receiving surface. The out-of-register sensing processor senses an amount of out-of-register, being a distance between the first and second portions. The out-of-register adjusting processor adjusts at least one of the first and second line image signals in such a manner that an effect of the amount of out-of-register on a color image reproduced from the first and second line image signals is reduced.
REFERENCES:
patent: 4812912 (1989-03-01), Iida et al.
patent: 5485209 (1996-01-01), Muramoto et al.
An English Language abstract of JP-8-167972.
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Lee Cheukfan
LandOfFree
Image reading device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image reading device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image reading device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617191