Television – Camera – system and detail – With single image scanning device supplying plural color...
Reexamination Certificate
1998-03-27
2002-07-30
Christensen, Andrew B. (Department: 2612)
Television
Camera, system and detail
With single image scanning device supplying plural color...
C348S373000, C348S219100
Reexamination Certificate
active
06426773
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an image pickup device and more particularly, to an image pickup device for inputting high-quality color image information for an object to be picked up by using image pickup elements.
BACKGROUND OF THE INVENTION
In order to obtain color image information, image pickup elements each having sensitivity for a different wavelength such as R, G, and B (Elementary colors) or Y, M, C, and G (Complementary colors) are generally required. For this reason, there have been three types of image pickup systems based on the conventional technology.
Namely, a first image pickup system is based on a technique for obtaining color image information for each color of R, G, and B by incorporating color filters in an optical system for picking up and sequentially switching the color filters.
FIG. 35
is a view schematically showing an image pickup device employing the first image pickup system. In the first image pickup system, as shown in
FIG. 35
, a R (Red) filter
402
, a G (Green) filter
403
, and a B (Blue) filter
404
are provided as color filters in a section between an optical system for picking-up
401
and an image pickup element
405
.
The color filters are sequentially switched to each other by moving the R (Red) filter
402
, G (Green) filter
403
, and B (Blue) filter
404
in a direction indicated by the arrow S (in the vertical direction in the figure) In the first image pickup system, it takes a long time to obtain color image information due to effects by this switching operation.
A second image pickup system is based on a technique for separating an image of a picked-up object into three colors with a dichroic prism or the like and obtaining color image information for each color from images of the picked-up object each obtained by having been subjected to color separation into R, G, and B respectively with three sheets of image pickup elements, and this technique is generally referred to as a 3CCD system.
FIG. 36
is a view schematically showing an image pickup device employing the second image pickup system. In the second image pickup system, as shown in
FIG. 36
, a dichroic prism
505
is provided in a section surrounded by an optical system for picking-up
501
and a R-image pickup element
502
, a G-image pickup element
503
, and a B-image pickup element
504
.
Although there is a merit of enabling concurrent acquisition of color image information for colors (R, G, and B) in the second image pickup system as compared to that in the first image pickup system, a complicated prism has to be used or three sheets of R, G and B image pickup elements
502
,
503
and
504
are required, which causes a price of the device to be extremely high.
A third image pickup system is based on a technique for obtaining color information with sensitivity for a different wavelength for each pixel received by a solid-state image pickup element system.
FIG. 37
is a view schematically showing an image pickup device employing the third image pickup system,
FIG. 38
is a view showing a color array on a light-sensing element,
FIG. 39
is a view showing an example of a picked-up object having light and dark, and
FIG. 40
is a view showing a density level corresponding to each color. In the third system, a solid-state color image pickup element
602
has color filters provided on light-sensing elements two-dimensionally arrayed as shown in
FIG. 38
, and the light-sensing elements are arrayed so that each of the elements has sensitivity for a different wavelength for each pixel.
In this third image pickup system, as shown in
FIG. 37
, color information can be obtained with sensitivity for a different wavelength for each pixel received by the solid-state color image pickup element
602
through an optical system for picking-up
601
. Although there is a merit of enabling acquisition of color image information with a single plate in the third image pickup system, it is not possible to obtain color information for the same section of the same object to be picked up because the light-sensing elements each having sensitivity for a different wavelength are arrayed on one plane.
For this reason, as shown in
FIG. 39
, when color image information for a certain image of picked-up object having light and dark sections in each pixel is obtained by a solid-state color image pickup element with the color array as shown in
FIG. 38
, signals corresponding to the colors R, G and B are generated as shown in FIG.
40
. The phenomenon described above is generally referred to as a pseudo color. To prevent this type of phenomenon, it is necessary not to receive an image having light and dark sections shown in
FIG. 39
, namely a high frequency image. Namely, in general, the image is shaded off by providing an optical low-pass filter in the picking-up optical system
601
, so that generation of the pseudo color can be prevented by making use of the shading-off.
When the image has been shaded off by the optical low-pass filter, however, a high-resolution image can not be obtained. There has been proposed, as a method of solving this problem, for example, “Image pickup device for high-quality images” disclosed in Japanese Patent Laid-Open Publication No. HEI 7-322121.
Disclosed in this Publication is a technology in which a position of an image of a picked-up object is displaced to image pickup elements by using a VA (Variable Angle) prism as an optical axis changing device so that a high-quality image is obtained through this displacement. With this technology, assuming a total number of pixels of the image pickup elements is m-pixels obtained by fetching the same image a plurality of times, if images of n-types of different picked-up objects are fetched, images equivalent to n×m-pixels are obtained.
The technology according to this Publication is a combined system obtained by combining the second image pickup system with the third image pickup system. FIG.
41
and
FIG. 42
are views each for explaining this combined system with a color array. In this combined system, color information of C, Y, M and G each for the same section of an object to be picked up is obtained by displacing an image pickup element having the color array (Refer to
FIG. 41
) of filters for complementary colors of C (Cyan), Y (Yellow), M (Magenta), and G (Green) by one pixel pitch in four directions horizontally and vertically to obtain four sheets of color image information as shown in FIG.
42
.
In the image pickup device for high-quality images based on the conventional technology like that disclosed in the Publication, the second image pickup system is performed in time sequence by displacing an image of an object to be picked up, so that four-color image information is sequentially obtained because changing is executed like in the first image pickup system although a pseudo color like in the third image pickup system does not occur. For this reason, although the occurrence of a pseudo color is prevented by the second system, there occur such problems as that an unnecessarily long time is spent for image pickup, that hands are unintentionally moved in taking a picture, or that a two axial displacing device (horizontal direction and vertical direction) is required for displacing an image pickup element in the hour directions horizontally and vertically.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image pickup device in which occurrence of a pseudo color and unintentional movement of hands in taking a picture can be prevented with a simple configuration.
An image pickup device according to the present invention comprises, an optical input unit for optically inputting an image of an object to be picked up; an image pickup unit, in which light-sensing elements each having sensitivity for a different wavelength are two-dimensionally arrayed, for obtaining color image information from the image of the picked-up object inputted from the optical input unit; a relative position displacing unit connected to the image pickup unit for relatively
Christensen Andrew B.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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