Facsimile and static presentation processing – Natural color facsimile – Scanning
Reexamination Certificate
1996-11-07
2001-03-06
Lee, Cheukfan (Department: 2722)
Facsimile and static presentation processing
Natural color facsimile
Scanning
C358S506000, C358S518000
Reexamination Certificate
active
06198550
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scanner system and, more particularly, to a scanner system having a function of, using a computer, correcting any color misregistration generated in reading a color image by a scanner.
2. Description of the Related Art
Generally, a linear sensor is used as the image sensing device of a scanner for reading a color image.
In this case, two systems are available to convert the read image into a color image, e.g., to separate the image into three primary colors (R, G, and B), i.e., red, green, and blue components: a system which separates the light source into three primary colors and scans the image three times (“three-pass system”) and a system which scans the original only once using a color CCD linear sensor which has a plurality of arrays of charge-coupled devices (CCDs) with three primary color filters formed thereon (“one-pass system”).
In the RGB system, as the linear sensor used for the latter one-pass system, a “two-line linear sensor” having a total of two arrays of CCDs, i.e., an array of green CCDs and an array of red/blue CCDs, or a “three-line linear sensor” having three arrays of CCDs for red, green, and blue can be used.
FIGS. 14A
to
14
C are schematic views showing conventional linear sensors.
FIGS. 14A and 14B
respectively show a two-line linear sensor and a three-line linear sensor.
R, G, and B in these drawings represent pixels of red, green, and blue CCDs, respectively, which are aligned in the main scanning direction (longitudinal direction) of the sensor.
The three-line linear sensor shown in
FIG. 14B
prepares data of one pixel of an image on the basis of outputs from the G, B, and R pixels aligned in the horizontal direction.
The two-line linear sensor shown in
FIG. 14A
prepares data of one pixel of an image on the basis of outputs from the G, B, and R pixels adjacent to each other. However, since the number of B or R pixels is ½ that of G pixels, B and R data are used twice to prepare image data.
When an original is sensed by a so-called “one-pass system” using a sensor having a plurality of lines in the main scanning direction, a color misregistration inevitably occurs because of its principle.
This is because the R, G, and B values constituting one pixel of the sensed image are obtained by sensing the original at positions slightly shifted from each other.
To cope with this problem, the conventional scanner temporarily stores a sensed image signal and reads the signal from a buffer incorporated in the scanner main body at a timing at which such color misregistration may not occur.
In some cases, the buffer is incorporated not in the scanner main body but in the linear sensor, and such a buffer incorporated type linear sensor as shown in
FIG. 14C
is used. With this arrangement, the entire scanner apparatus can be easily controlled.
As described above, the conventional scanner uses a buffer incorporated type linear sensor as shown in
FIG. 14C
to temporarily store a sensed image signal in the buffer and reads out the signal from the buffer at a predetermined timing, thereby preventing a color misregistration.
Such a buffer is sometimes separately arranged in the scanner main body, instead of in the linear sensor.
However, when the buffer is arranged in the scanner main body, the scanner becomes bulky, and the apparatus becomes expensive accordingly.
In case of the buffer incorporated type linear sensor as well, a sub-scanning direction in which color misregistration correction can be performed is limited to only one direction. When a sub-scanning operation is performed in the opposite direction, the color misregistration undesirably increases. Therefore, a bidirectional sub-scanning operation cannot be performed though it is convenient in practice.
When an original is to be read with various resolutions, the degree of color misregistration changes depending on the read resolution. When a buffer is used to shift the timing of outputting the image signal, the color misregistration undesirably increases.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above disadvantages, and has as its object to provide a scanner system capable of performing color misregistration correction processing regardless of the sub-scanning direction or read resolution.
According to an aspect of the present invention, there is provided a scanner system comprising a scanner for sensing a color original image by a linear sensor constituted by a plurality of solid state image sensing device arrays, and an information processing unit for processing an image signal output from the scanner, wherein the information processing unit has correction means for correcting a color misregistration between image signals output from the plurality of solid state image sensing device arrays.
According to another aspect of the present invention, there is provided a scanner system for reading a color original image, comprising a scanner having a linear sensor constituted by a plurality of solid state image sensing device arrays to sense the color original image and output an image signal, and control means for outputting a control signal for defining a predetermined condition of a sensing operation by the linear sensor, and an information processing unit having color misregistration correction means for correcting, on the basis of the control signal output from the control means, a color misregistration between image signals sensed by the plurality of solid state image sensing device arrays.
The scanner has resolution selection means for selectively switching a read resolution, and the control signal output from the control means comprises at least one of a signal containing information of a sub-scanning direction of the linear sensor and a signal representing a resolution set by the resolution selection means.
More specifically, in the above-described scanner system, the plurality of solid state image sensing device arrays constituting the linear sensor of the scanner transfer read image information including a color misregistration generated because of their structures to the information processing unit connected for color misregistration correction of the image information.
This information processing unit performs predetermined correction processing for the color misregistration between the image signals output from the plurality of solid state image sensing device arrays constituting the linear sensor under the control of the color misregistration correction means of the control means in consideration of the predetermined sensing condition of the linear sensor (e.g., the resolution selected by the resolution selection means or the size of image sensing device arrays).
With this processing, the color misregistration amount contained in the read image information converges to zero to be removed or is reduced to a minimum.
According to still another aspect of the present invention, there is provided a method of correcting a color misregistration in an image signal in a computer system which executes processing of the image signal from a scanner including a linear sensor for reading an original in accordance with a predetermined sub-scanning parameter, comprising the steps of:
receiving the image signal from the scanner and the predetermined sub-scanning parameter and storing the image signal and the sub-scanning parameter in a memory;
determining a displacement amount for correcting the color misregistration in the image signal in accordance with the predetermined sub-scanning parameter read out from the memory; and
performing predetermined image arithmetic processing for the image signal read out from the memory in accordance with the determined displacement amount, thereby correcting the color misregistration.
According to still another aspect of the present invention, there is provided an article of manufacture comprising:
a computer readable memory medium having computer readable program coding means recorded to execute processing of an image signal from a
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Lee Cheukfan
Olympus Optical Co,. Ltd.
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