JP3397397B2 - Imaging device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to a high resolution image information easily obtained by using a plurality of image pickup elements having a limited number of pixels without increasing the number of pixels of the image pickup element. The present invention relates to an image pickup apparatus suitable for, for example, a small video camera or a still video camera.

[0002]

2. Description of the Related Art In recent years, solid-state area sensors (image sensors in which pixels are two-dimensionally arrayed) used as image pickup devices in image pickup devices have become capable of increasing the number of pixels, lowering their prices, and further reducing their size. Therefore, it has been widely applied to home-use compact video cameras, still video cameras, and the like, and sufficient image quality has been obtained in televisions of current standards such as NTSC.

FIG. 10 is a schematic view of a main part in the vicinity of an image pickup element of a conventional single plate type image pickup apparatus.

In the figure, 101 is a taking lens and 102
Is an optical filter, and is composed of, for example, a low-pass filter or a near-infrared light cut filter. Reference numeral 103 denotes a solid-state image sensor, which is composed of, for example, an area sensor, and a color filter having a filter array as shown in FIGS. 11 and 12 is provided on the surface of the image sensor 103. In the figure, an output signal (image information) obtained by the image sensor 103 is processed by a signal processing circuit (not shown), and thereby a colorized video signal is obtained and color reproduction is performed.

In order to obtain an output signal (image information) having a higher resolution than that of a single-plate type image pickup device, a two-plate type or three-plate type image pickup device as shown in FIGS. 13 and 14 is required. .

In FIGS. 13 and 14, 101 is a taking lens, and 102 is an optical filter, which is composed of, for example, a low-pass filter or a near infrared light cut filter. Reference numeral 104 denotes a dichroic prism (or a half mirror) as a color separation means, which separates the incident light into two color lights in FIG. 13 and the incident light into three color lights in FIG. There is. 103A, 10
Reference numerals 3B and 103C are solid-state image pickup devices, each of which is composed of, for example, an area sensor and is provided on the exit surface of each prism.

In these image pickup devices, an output signal (image information) obtained from each solid-state image pickup element 103A, 103B, 103C is processed by a signal processing circuit (not shown) to obtain a colorized video signal. Color reproduction is performed.

[0008]

However, although the number of pixels of the image pickup device has been increasing in recent years in the conventional single-plate type image pickup device, its resolution is limited by the number of pixels of the solid-state image pickup device. It is difficult to reduce the cost because it is not possible to obtain an image with a resolution of 2) and the image pickup device with a high number of pixels is very expensive.

On the other hand, in a two-plate type or three-plate type image pickup device, since an optical member such as a dichroic prism or a half mirror is used as a color separation means, the back focus of the photographing lens becomes extremely long and the entire device is miniaturized. There was a problem that could not be achieved. Further, these optical members are expensive, and thus it is difficult to reduce the cost.

According to the present invention, a plurality of image pickup devices having a limited number of pixels are used to appropriately set the arrangement of the image pickup devices and the respective optical elements constituting the image pickup system when a subject image is formed on each image pickup device. In addition, by providing a filter with different spectral transmittance on each image pickup element surface, it is possible to provide a multi-plate and color display and to provide an image pickup device that easily obtains high-definition image information (color image). With the goal.

[0011]

According to a first aspect of the present invention, there is provided an image pickup apparatus, wherein a first optical system forms a subject image on a predetermined image formation plane, and the image is formed on the optical axis of the first optical system. A second optical system having a second optical system arranged near the planned image plane and a plurality of lens systems having an optical axis outside the optical axis of the first optical system and arranged behind the second optical system. All of the subject images formed on the planned image forming surface by the optical system of 3 are re-imaged on the plurality of image pickup devices of the image pickup means having a plurality of image pickup devices corresponding to the plurality of lens systems, respectively. An image pickup apparatus for obtaining high-definition image information by using image information obtained by the image pickup element of 1., wherein filters having different spectral transmittances are provided on the plurality of image pickup element surfaces. It has a feature.

According to a second aspect of the present invention, an image pickup apparatus forms an image of a subject on a planned image forming plane by the first optical system, and has the same optical axis as the first optical system arranged near the planned image forming plane. Second
And an optical axis different from the optical axes of the first optical system,
All of the subject images formed on the planned image forming surface by the third optical system having a plurality of lens systems arranged behind the second optical system correspond to the plurality of lens systems of the third optical system. An image pickup apparatus which forms an image on each of a plurality of image pickup device surfaces of an image pickup device having a plurality of image pickup devices, and synthesizes image information from the plurality of image pickup devices to obtain image information about an entire subject image. Then, filters having different spectral transmittances are provided on the surfaces of the plurality of image pickup devices.

[0013]

FIG. 1 is a sectional view of the essential parts of an optical system according to the first embodiment of the present invention, and FIG. 2 is a perspective view of the essential parts of the first embodiment of the present invention.

In the figure, reference numeral 1 denotes a first optical system, which forms a subject image on a primary image forming surface (planned image forming surface) 21.

Reference numeral 2 is a second optical system, and the first optical system 1
Of the subject image formed on the primary image forming surface 21 and is guided to the subsequent lens system. .

The third optical system 3 has two lens systems, a 31st lens system 3A and a 32nd lens system 3B.

The two lens systems 3A and 3B have an optical axis outside the optical axis of the first optical system 1, and the optical axis of the second optical system 2 is sandwiched behind the second optical system 2. Are arranged in each.

Reference numeral 31 denotes an image pickup means, which has, for example, two image pickup elements 31A and 31B formed of a solid area sensor,
The two lens systems 3A and 3B are arranged on the image planes.

In this embodiment, FIG.
A green (G) color filter is provided as shown in (A), and a red (R) color filter and a blue (B) color filter are provided on the surface of the image pickup device 31B as shown in FIG. 3B. In the main scanning direction (horizontal direction on the drawing) and sub-scanning direction (vertical direction on the drawing)
The color filters are arranged alternately.

Two lens systems (3A, 3A) of the third optical system
B) shows image pickup devices 31A and 31B respectively corresponding to all the subject images on the primary image formation surface 21 formed by the first optical system 1.
It is re-imaged on the surface.

In this embodiment, the second optical system 2 has the pupils 3A1 and 3B1 of the plurality of lens systems 3A and 3B that form the third optical system 3 as shown by the solid optical path 32 in the figure.
An image is formed in the vicinity of the pupil region of the optical system 1.

In this embodiment, as shown in FIG.
The subject image is formed on the primary image forming surface 21 by the optical system 1 and the subject image is formed by the two lens systems 3A and 3B of the third optical system 3 through the second optical system 2. All the subject images formed on the surface 21 are formed on the surfaces of the image pickup devices 31A and 31B, respectively.

Then, the output signals (image information) from the two image pickup devices 31A and 31B are processed by a signal processing system (not shown) which will be described later to obtain colorized video signals and reproduce colors. .

Next, the image processing method of this embodiment will be described with reference to FIG. This figure is a block diagram of the essential parts of the video signal processing unit (signal processing system) of the image pickup apparatus of this embodiment.

In the figure, 31A and 31B are image pickup devices, and the color filters shown in FIG. 3 are provided on the surfaces of these image pickup devices 31A and 31B, respectively.

In the present embodiment, the entire subject image formed on the image pickup device 31A is converted into an electric signal (G signal) from the image pickup device 31A.
As a sample hold circuit (S / H circuit) 5
The sample is held by 1A, the analog signal is converted into the digital signal by the analog-digital conversion circuit (A / D conversion circuit) 52A, and the converted signal is stored in the memory (storage circuit) 53A.

Further, the entire subject image formed on the image pickup device 31B is output as an electric signal (R signal and B signal are alternately output) from the image pickup device 31B, and each sample hold circuit (S / H circuit). ) 51B and 51C sample and hold at the timings of the R signal and the B signal, respectively, to separate them into the R signal and the B signal. Then, each signal is converted from an analog signal to a digital signal by each analog-digital conversion circuit (A / D conversion circuit) 52B, 52C and stored in each memory (storage circuit) 53B, 53C.

The G signal stored in the memory 53A is input to the luminance signal processing circuit 54 and the color signal processing circuit 55. The brightness signal processing circuit 54 performs necessary signal processing on the G signal as a brightness signal, such as automatic gain control (AGC) and gamma correction, and outputs the brightness signal as a brightness signal.

The R and B signals stored in the memories 53B and 53C are read out from the memories 53B and 53C, and are input to the color signal processing circuit 55.

The color signal processing circuit 55 performs processing such as AGC, gamma correction, and white balance adjustment on the input R, G, and B signals, and performs matrix processing to output color difference signals. . Then, a colorized video signal is obtained using these signals to perform color reproduction.

In this embodiment, each image pickup device 31A,
The arrangement of the filters provided on the surface 31B is not limited to the arrangement shown in FIG. 3, and any filter arrangement may be used as long as a color image signal can be obtained as shown in FIGS. The invention can be applied in the same manner as the above-described first embodiment.

That is, in FIG. 5, a G (green) color filter is provided on the surface of the image sensor 31A, and red (R) and blue (B) filters are alternately arranged on the surface of the image sensor 31B in the main scanning direction. The color filters are arranged in the. In FIG. 6, a white (W) color filter is provided on the surface of the image sensor 31A, and red (R), green (G), and blue (B) filters are provided on the surface of the image sensor 31B. The color filters are arranged alternately.

In particular, with the filter arrangement as shown in FIG. 6, for example, when a high resolution image is not required, it is possible to use only the image pickup device 31B to pick up an image.

In this embodiment, as described above, the output signals (image information) from the two image pickup devices 31A and 31B arranged on the image forming planes of the two lens systems 3A and 3B of the third optical system 3 are described above. By obtaining a color video signal by using it, it is possible to perform multi-plate and colorization without using an optical member such as a dichroic prism or a half mirror as a color separation means unlike a conventional image pickup device, and thereby, a photographing lens. No longer limits the back focus of.

FIG. 7 is a perspective view of the essential portions of Embodiment 2 of the present invention. In the figure, the same elements as those shown in FIG. 1 are designated by the same reference numerals.

This embodiment is different from the first embodiment described above in that the third optical system 3 is replaced by three lens systems 3A, 3B and 3C.
Image pickup elements 31A, 31B, 31C are arranged on the image forming planes of the three lens systems 3A, 3B, 3C, and color filters having different spectral transmittances on the image pickup elements 31A, 31B, 31C, respectively. Is provided. Other configurations and optical functions are substantially the same as those in the first embodiment.

That is, as shown in FIG. 8, a red (R) color filter is provided on the surface of the image sensor 31A, a green (G) color filter is provided on the surface of the image sensor 31B, and a blue filter is provided on the surface of the image sensor 31C. (B) Each color filter is provided, and all the object images formed on the primary image formation surface 21 by the first optical system 1 are imaged by the third optical system 3 through the second optical system 2. Images are formed on the surfaces of the elements 31A, 31B, and 31C, respectively, and processed by a signal processing system (not shown) using output signals (image information) from the imaging elements 31A, 31B, and 31C to obtain a color video signal, and color is obtained. It is reproduced.

In this embodiment, each image pickup device 31A,
The array of color filters provided on the surfaces 31B and 31C is not limited to the filter array shown in FIG. 8, but any filter array may be used as long as a color image signal is obtained as shown in FIG. The invention can be applied in the same manner as the above-mentioned second embodiment.

That is, in FIG. 9, a yellow (Ye) color filter is provided on the surface of the image sensor 31A, a magenta (Mg) color filter is provided on the surface of the image sensor 31B, and a cyan (Cy) is provided on the surface of the image sensor 31C. ) By providing a color filter, it is possible to obtain the same effect as in the second embodiment.

[0040]

According to the present invention, as described above, each element of the image pickup device is appropriately configured, and different spectral components are formed on the respective image pickup element surfaces arranged on the image forming planes of the plurality of lens systems of the third optical system. By providing a transmittance filter, multiple plates and colors can be obtained without using an optical member such as a dichroic prism or a half mirror as a color separation unit, which limits the back focus of the photographic optical system. It is possible to achieve an image pickup apparatus that can easily obtain a high-resolution image (color image) by using an image pickup element having a limited number of pixels.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of an optical system according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an arrangement of color filters provided on each image pickup device surface according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a main part of a signal processing unit according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an arrangement of color filters provided on each image sensor surface according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the arrangement of color filters provided on the surface of each image sensor according to the first embodiment of the present invention.

FIG. 7 is a perspective view of essential parts of Embodiment 2 of the present invention.

FIG. 8 is an explanatory diagram showing an arrangement of color filters provided on each image pickup element surface according to the second embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an arrangement of color filters provided on each image pickup element surface according to the second embodiment of the present invention.

FIG. 10 is a schematic view of a main part of a conventional imaging device.

FIG. 11 is an explanatory diagram showing an array of color filters provided on the surface of an image sensor of a conventional image sensor.

FIG. 12 is an explanatory diagram showing an array of color filters provided on the surface of an image sensor of a conventional image sensor.

FIG. 13 is a schematic view of a main part of a conventional two-plate type imaging device.

FIG. 14 is a schematic view of a main part of a conventional three-plate type imaging device.

[Explanation of symbols]

1 1st optical system 2 2nd optical system 3 3rd optical system 21 1st imaging plane 31 Image pick-up means 3A, 3B, 3C Lens system 31A, 31B, 31C Image pick-up element 51A, 51B, 51C Sample hold circuit 52A , 52B, 52C A / D conversion circuits 53A, 53B, 53C Memory 54 Luminance signal processing circuit 58 Color signal processing circuit

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Makoto Sekida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Eio Ogura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Nobuhiro Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masashi Hori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Toshikazu Yanai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshihiro Honma 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masato Kosugi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-58-76807 (JP, A) (58) Fields investigated (Int.Cl. ⁷⁾ , DB name) H04N 9/04-9/11 H04N 5/222-5/257 H04N 5/335

Claims (2)

(57) [Claims] 1. A second optical system which forms a subject image on a planned image forming plane by the first optical system, and is arranged on the optical axis of the first optical system and near the planned image forming plane. , A third optical system having an optical axis outside the optical axis of the first optical system and having a plurality of lens systems arranged behind the second optical system, is formed on the planned image forming surface. respectively re formed on the imaging device of said plurality of image pickup means having a plurality of image pickup elements corresponding to all of the subject image to the plurality of lens systems, by utilizing the image information obtained by the image pickup device of the plurality of high-resolution An image pickup apparatus for obtaining various image information, characterized in that filters having different spectral transmittances are provided on the surfaces of the plurality of image pickup elements. 2. An object image is formed on a planned image forming surface by a first optical system, and a second optical system having the same optical axis as that of the first optical system arranged near the planned image forming surface. have a light axis different from the optical axis of the first optical system, arranged behind the second optical system
Of the image pickup means having a plurality of image pickup elements corresponding to the plurality of lens systems of the third optical system for all the subject images formed on the planned image forming surface by the third optical system having a plurality of lens systems. An image pickup apparatus for forming an image on each of the plurality of image pickup device surfaces, and combining image information from the plurality of image pickup device to obtain image information about an entire subject image. An image pickup apparatus comprising: a filter having different spectral transmittances.