JPH09224180A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously realize high resolution and miniaturization by dividedly picking up the image of an object while combining plural image pickup systems. SOLUTION: The image of a subject is respectively formed on CCD 3a-3d by image pickup lenses 2a-2d, photoelectric transduced and signal-processed as video signals in preprocessing circuits 4a-4d. The outputs from the preprocessing circuits 4a-4d are respectively inputted to distortion correction circuits 5a-5d, and the geometric distortion such as magnification color aberration or distortion aberration caused by the image pickup lenses 2a-2d is corrected through memories 6a-6d. The corrected signals are synthesized as an image by a synthesizer circuit 7. In this case, the image pickup lenses 2a-2d respectively pick up images in the different image pickup areas of the object, and part of the image is mutually overlapped at the surrounding section of each image pickup area. Besides, in order to pick up the images in different areas like this, the image pickup lenses 2a-2d are parallelly provided so that their optical axes can mutually have a fixed angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device applied to a video camera or the like, and more particularly, by combining an image pickup system using an image pickup device having a low number of pixels, which is low in cost, small size, low cost and high cost. The present invention relates to an image pickup device capable of achieving high image quality or high functionality.

[0002]

2. Description of the Related Art In recent years, in the field of consumer video cameras and electronic still cameras, the size and weight of cameras have been reduced and the cost has been reduced, and sufficient image quality has been obtained as long as they comply with the NTSC standard. Further, as the image pickup device which is a key device, a CCD having about 250,000 to 400,000 pixels is very inexpensive. On the other hand, the spread of personal computers has made it possible to handle images on a display having a higher resolution than the conventional NTSC standard. In addition, the chances of handling video on a computer have increased, and when using functions such as zooming and shifting, it has become necessary to provide images with higher definition than the resolution of the display. Further, a general image includes a large amount of character information, and in the sense of capturing an image so that the character can be read, a higher definition of the input system is desired.

Currently, as a high-definition camera, a TV camera for HDTV is typical, and a CCD having 2 million pixels is also used as an image pickup element. However, 2 million pixel CCD
Is very expensive and difficult to use as an input device for a personal computer. In addition, 2 million pixels is not enough when dealing with text information and using it assuming hard copy.

As a method for solving the above-mentioned problems, various methods have been proposed for obtaining high definition by combining elements having a small number of pixels. For example, as represented by the technique disclosed in Japanese Patent Laid-Open No. 7-12315, an optical means is provided behind an imaging lens to divide a subject image into a plurality of images, and the images are combined to obtain a high resolution image. There is a way to get. See also
The so-called pixel shift method proposed in Japanese Patent No. 52, for example, divides the optical path by arranging a prism on the image plane side of the imaging lens and forms the same subject image on different image planes. On the other hand, it is an imaging method that obtains a high resolution by imaging with CCDs spatially displaced from each other by half a pixel.

[0005]

However, in the above-mentioned conventional technique, the method of obtaining a high resolution by dividing the subject image into a plurality of images and capturing the subject image requires an optical system for once focusing the subject. Since there is only one optical system for the subject, and its size depends on the size of the image of the subject, miniaturization is extremely difficult. Similarly, in the pixel shift method, one imaging lens is required for a subject, size reduction is difficult, and since the same image is captured by a plurality of elements, it is difficult to obtain high resolution as much as the number of pixels.

Therefore, an object of the present invention is to provide an image pickup apparatus capable of simultaneously realizing high resolution and downsizing by combining a plurality of image pickup systems and taking an image by dividing a subject. .

[0007]

In order to achieve the above object, an image pickup apparatus of the present invention comprises a plurality of image pickup lenses for photographing an object and a plurality of image pickup lenses for photoelectrically converting the images formed by these image pickup lenses. The image pickup device includes an image pickup device and a video signal generation unit that generates one video signal by processing and combining electric signals from the respective image pickup devices. The image pickup lens is arranged so that a part of the images overlap each other, and by adopting this configuration, an image pickup system using an image pickup device having a low number of pixels, which is low in cost, is combined to reduce the size,
It is possible to obtain an image pickup device that is inexpensive, has high image quality, and is highly functional.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention includes two or more image pickup lenses for photographing an object, and two or more image pickup for photoelectrically converting an image formed by each of the image pickup lenses. A device and a video signal generation unit that generates one video signal by processing and synthesizing the electric signals from the two or more imaging devices, each output from the two or more imaging devices. The image pickup lens is arranged such that part of the images of the subject overlap with each other, and this configuration enables combination of an image pickup system using an image pickup element with a low pixel count, which is low in cost. Moreover, high-quality or high-performance imaging is performed.

According to a second aspect of the present invention, a four-sided mirror that divides light information from the subject into four directions, and a divided subject that is arranged close to each surface of the four-sided mirror. Four image pickup systems each including an image pickup lens that captures a space and an image pickup device that photoelectrically converts an image of the image pickup lens, and an electric signal from the four image pickup systems is processed and combined to generate one video signal. And a video signal generation unit that operates the four image mirrors, and the four image mirrors are arranged such that the respective subject images output from the four image pickup systems partially overlap each other.
It is possible to combine an image pickup system using an image pickup element having a low pixel count, which is low in cost, and further, image pickup with high image quality or high function is performed.

According to a third aspect of the present invention, the area where the images of the respective subject images overlap each other is 0.5 ×, where S is the area of each of the subject images and D is the area of a part of the overlapping images. The image pickup lens is arranged so as to satisfy the relational expression S> D, and by setting the image pickup lens within the above range, it is possible to make the images overlap properly for signal processing.

According to a fourth aspect of the present invention, the video signal generating section includes a distortion correcting section that electrically corrects the distortion of an image generated by the imaging lens, and a combining section that combines the corrected images. However, a good image signal is generated.

According to a fifth aspect of the present invention, the distortion correction section simultaneously corrects the chromatic aberration of magnification and the distortion aberration caused by the imaging lens, so that a good image signal is generated.

According to a sixth aspect of the present invention, the distortion correction section divides the subject image formed on each of the image pickup devices into a plurality of areas, and performs linear address conversion calculation for each of the areas. Is performed to correct geometrical distortion, and a good image signal is generated.

According to a seventh aspect of the present invention, the optical axis of each of the image pickup lenses and the center of each of the image pickup devices are displaced from each other, and it is possible to prevent occurrence of image distortion during short-distance shooting. it can.

A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration for explaining a first embodiment of the present invention. Reference numeral 1 denotes an image pickup system, which has four fixed focus lenses 2a to 2d having no focus adjustment function. And four CCDs 3a to 3d as image pickup elements having a diagonal length of 1/4 inch and corresponding to 300 to 400,000 pixels, and preprocessing circuits 4a to 4d. The subject images are formed on the CCDs 3a to 3d by the image pickup lenses 2a to 2d, photoelectrically converted, and subjected to signal processing as video signals in the preprocessing circuits 4a to 4d. Outputs from the preprocessing circuits 4a to 4d are input to distortion correction circuits 5a to 5d, respectively, and geometric distortions such as chromatic aberration of magnification and distortion caused by the imaging lenses 2a to 2d are corrected via the memories 6a to 6d. .

Each of the memories 6a to 6d stores R, G, B data of 8 bits per pixel as two-dimensional image information.
640 pixels horizontally and 480 vertically for each color of
Stored as pixel information, distortion correction circuits 5a-5d
Then, first, a new address value (horizontal direction x, vertical direction y) is corrected so that the address (horizontal direction h, vertical direction v), which is the position of the pixel, is corrected based on the following formula (Equation 1). ). However, in the same equation, Ax, B
x, Cx, Ay, By, Cy, Aw, Bw, and Cw are conversion coefficients according to the amount of geometric distortion.

[0018]

[Equation 1]

The corrected image processed by the above equations is a modified image of the uncorrected image, and data may not exist on the 640 × 480 set as the image format. It is necessary to calculate the signal amount S (h ', v') of the pixel in the image format (however,
h ', v'are address values after distortion correction corresponding to the image format). The S (h ′, v ′) is the image position (h ′,
In the vicinity of v ′), the position (xn,
yn). As a specific method for obtaining this, the average of signal amounts of neighboring m pixels, that is, the following equation (2) is used.

[0020]

[Equation 2]

Further, the S (h ', v') is the neighborhood of (x
each point (n, yn) (if four points, n = 1 to 4) and the point (h ',
It can be obtained by interpolation from the distance v ').

The geometrically corrected signals are combined as an image by the combining circuit 7. Here, the imaging lens of the imaging system 1
As shown in FIG. 2, 2a to 2d respectively capture imaged regions 8a to 8d of different subjects, and their images partially overlap each other around the respective imaged regions. The overlapping regions must overlap each imaging region in the horizontal and vertical directions by at least about 1% in length. This is to prevent image loss in the imaging regions 8a to 8d due to the deformation of the image due to the correction of the geometrical distortion. Further, the maximum of the overlapping regions is preferably 0.5 × S> D, where S is the area of each subject image and D is the area of a part of the overlapping images. The imaging lenses 2a to 2d are arranged so as to be in the overlapping state.

Combining four images as shown in FIG.
In the synthesizing circuit 7, the synthesizing may be performed based on the position stored in the memory set in advance at the time of setting, or the synthesizing may be performed by searching for the position having the highest correlation in the overlapping portion.

Further, in order to image different areas as described above, in the first embodiment, the image pickup lenses 2a to 2d have the same optical axes L of the four image pickup lenses 2a to 2d as shown in FIG. They are juxtaposed so as to have an angle u. Further, when the image pickup lenses 2a to 2d have a zoom function or a focus function, it is necessary to change the angle u, so that a special mechanism is required.

The image finally obtained in the synthesizing circuit 7 having the above-mentioned configuration is a high-definition image equivalent to the image obtained by the image pickup device having 1.5 million pixels.

FIG. 4 is a perspective view for explaining the structure of the main part of the image pickup system according to the second embodiment of the present invention, and the image pickup system 9 of FIG. 4 is configured to make the thickness of the system as thin as possible. . The four-sided pyramidal four-sided mirror 10 splits light from a subject, and the area shown in FIG. 2 is imaged by the imaging lenses 11a to 11d installed so as to face each surface 10a to 10d of the four-sided mirror 10. The angles of the surfaces 10a to 10d of the four-sided mirror 10 are adjusted so as to be possible. The operation after the imaging lenses 11a to 11d is the same as the operation in the first embodiment described with reference to FIG. 1, and a combined high-definition image can be obtained.

FIG. 5 is a front view for explaining the constitution of the main part of the image pickup system in the third embodiment of the present invention. In the constitution of the image pickup lenses 2a to 2d shown in FIG. 3, the image pickup lens 2a is shown.
Since the optical axes of ~ 2d have an angle with each other, when photographing a short distance, for example, as shown in FIG. 6, a rectangular object to be photographed indicated by a broken line is a figure indicated by a solid line. The phenomenon of distortion occurs. In order to solve this problem, as shown in FIG. 5, the optical axes L of the imaging lenses 12a to 12d are displaced from the optical axes L of the imaging lenses 12a to 12d and the centers O of the imaging devices (CCD) 13a to 13d. It is possible to make them parallel, and it is possible to adopt a configuration in which image distortion does not occur.

As the image pickup system, in addition to the above-mentioned ones, for example, as shown in a perspective view for explaining the configuration of the main part of the image pickup system of the fourth embodiment shown in FIG. m,
By using a combination of the imaging lenses 14 of which n is a positive number, it is possible to obtain a high-definition image that cannot be realized by the conventional imaging device.

[0029]

As described above, according to the present invention,
With regard to an image pickup apparatus such as a video camera, a small-sized, inexpensive, high-quality image pickup apparatus can be provided by combining an image pickup system using an image pickup element having a low number of pixels, which is particularly low cost.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an image dividing method according to the first embodiment.

FIG. 3 is a perspective view of a main part of the image pickup system in the first embodiment.

FIG. 4 is a perspective view of a main part of an image pickup system according to a second embodiment of the present invention.

FIG. 5 is a front view of a main part of an imaging system according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram of an image distortion phenomenon in the first embodiment.

FIG. 7 is a perspective view of a main part of an image pickup system according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 ... Imaging system, 2a-2d, 11a-11d, 12a-12d, 14 ... Imaging lens, 3a-3d, 13a-13d ... CCD, 4a-4d ... Preprocessing circuit, 5a-5d ... Distortion correction circuit, 6a ... 6d ... memory,
7 ... Compositing circuit, 8a-8d ... Imaging area, 10 ... Mirror.

Claims (7)

[Claims] 1. A plurality of imaging lenses for photographing a subject, two or more imaging devices for photoelectrically converting an image formed by each of the imaging lenses, and an electric signal from the two or more imaging devices. And a video signal generation unit for generating one video signal by synthesizing the video signals and synthesizing the video signals so that each of the subject images output from the two or more imaging devices partially overlaps with each other. An imaging device in which the imaging lens is arranged. 2. A four-sided mirror that divides light information from a subject into four directions, an imaging lens that is arranged close to each surface of the four-sided mirror, and that captures the divided subject space, A four image pickup system including an image pickup device that photoelectrically converts the image of the image pickup lens, and a video signal generation unit that generates one video signal by processing and combining electric signals from the four image pickup systems. An image pickup apparatus comprising the four-sided mirrors arranged so that respective subject images output from the four image pickup systems overlap each other. 3. A relational expression of 0.5 × S> D, where S is an area of each of the subject images and D is an area of a part of the overlapped images, in a portion where the images of the subject images overlap each other. The image pickup apparatus according to claim 1, wherein the image pickup lens is arranged so as to satisfy the condition. 4. The image signal generation unit is configured by a distortion correction unit that electrically corrects the distortion of the image generated by the imaging lens, and a combining unit that combines the corrected images. Item 1. The imaging device according to Item 1 or 2. 5. The image pickup apparatus according to claim 4, wherein the distortion correction section simultaneously corrects lateral chromatic aberration and distortion that are caused by the image pickup lens. 6. The distortion correction unit divides a subject image formed on each of the image pickup devices into a plurality of regions, and performs a linear address conversion operation on each of the regions to perform geometrical operation. The image pickup apparatus according to claim 4, wherein various distortions are corrected. 7. The image pickup apparatus according to claim 1, wherein the optical axes of the respective image pickup lenses and the centers of the respective image pickup devices are displaced from each other.