JPH05316406A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain a picture with high picture quality. CONSTITUTION:Since a ratio of a focal distance f1 of a parabolic mirror M1 to a focal distance f2 of a parabolic mirror M2 is 4:3, an object image 21 whose aspect ratio is 4:3 in which a scale in the longitudinal direction (vertical direction in the Figure) is magnified by a multiple of 3/4 is an object image 23. The aspect ratio of the object image is 16:9 (=4:3X3/4), then the object image 23 whose aspect ratio is 16:9 is projected onto the entire image pickup face of a CCD 3, e.g. for use with so-called High Vision application whose aspect ratio is 16:9 as the object image 21 whose aspect ratio is 4:3 without waste of valid picture elements of the CCD3.

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 suitable for use in, for example, a digital electronic still camera for taking high quality still images.

[0002]

2. Description of the Related Art In a conventional digital electronic still camera, an aspect ratio of 4: 3 is obtained so that a reproduced still image having an aspect ratio of 4: 3 can be obtained in accordance with the size of, for example, a gravure photograph of a magazine or a news photograph. Charge-coupled device (CCD) having an image pickup surface part for forming the image signal of 3
(Hereinafter, it is described as a CCD having an aspect ratio of 4: 3).

[0003]

By the way, since the number of pixels of the CCD having the aspect ratio of 4: 3 currently manufactured is about 400,000, the reproduced still image obtained by the conventional apparatus is When printed as a photograph on printed matter, there was a problem that the image (photograph) had a very poor image quality.

Therefore, there is a method of using a so-called high-definition CCD having, for example, 2 million pixels, and the aspect ratio of this CCD is 16: 9. Therefore, the aspect ratio of a reproduced still image is 16 as well. : 9, so in order to use this still image for gravure photographs and news photographs of magazines, it is necessary to cut it in the horizontal direction and shorten it, and eventually the number of pixels used is about half of the original. However, there is still a problem that the image quality deteriorates.

The present invention has been made in view of such a situation, and makes it possible to obtain a high quality image.

[0006]

An image pickup apparatus of the present invention comprises a lens portion 1 as a lens means for forming an image of light, and a focus for reflecting the light imaged by the lens portion 1 on a two-dimensional parabolic surface. And the parabolic cylindrical mirrors M ₁ and M ₂ or the parabolic cylindrical mirrors M ₁₁ and M ₁₂ and the parabolic cylindrical mirrors as the first and second reflecting means having different focal lengths. It is characterized by including a CCD 3 as an image pickup means for photoelectrically converting the light reflected by M ₁ and M ₂ or the parabolic cylindrical mirrors M ₁₁ and M ₁₂ and outputting an image signal.

[0007]

In the image pickup apparatus having the above-mentioned structure, the lens unit 1 is provided by the parabolic cylindrical mirrors M ₁ and M ₂ or the parabolic cylindrical mirrors M ₁₁ and M ₁₂ which are arranged so that their focal points coincide with each other and have different focal lengths. The light imaged at is reflected by its two-dimensional parabolic surface and C
Photoelectric conversion is applied to the entire image pickup surface portion of the CD 3. Therefore,
By adjusting the focal lengths of the parabolic cylindrical mirrors M ₁ and M ₂ or the parabolic cylindrical mirrors M ₁₁ and M ₁₂ , for example, the effective pixel number of the high-definition CCD 3 having an aspect ratio of 16: 9 is not impaired. For example, a high quality image having an aspect ratio of 4: 3 can be obtained.

[0008]

1 is a block diagram showing the configuration of an embodiment of a digital electronic still camera to which an image pickup apparatus of the present invention is applied. The lens unit 1 forms an image of light and projects a subject image on the imaging surface of the CCD 3 via the aspect ratio conversion unit 2. The CCD 3 has, for example, 2 million effective pixels,
16: 9 aspect ratio C for so-called high-definition
The CD is controlled by the CCD driver 12 and photoelectrically converts the light (subject image) projected from the lens unit 1 through the aspect ratio conversion unit 2 into an image signal as an electric signal to be an A / D converter. Output to 4.

In the aspect ratio converter 2, for example, as shown in FIG. 2, the concave side of the two-dimensional parabolic surface is a reflective surface.
And its focal length parabolic cylinder plane mirror M ₁ is f _1, likewise two-dimensional paraboloid concave is in the reflective surface, composed of parabolic cylinder surfaces mirror M ₂ its focal length is f ₂ And parabolic mirror M ₁
And the parabolic mirror M ₂ are arranged so that their respective focal points coincide with each other.

Here, the two-dimensional paraboloid means, for example, FIG.
And has no curvature in the depth direction (direction perpendicular to the paper surface),
The vertical and horizontal curvatures of the drawing are constant regardless of the depth, and therefore the focal point forms a straight line in the depth direction.

The parabolic cylindrical mirror M ₁ reflects the object image 21 from the lens section 1 on the concave side of the two-dimensional parabolic surface and reflects the reflected light 22.
The focal point F (as described above, the parabolic cylindrical mirror M ₁ and the parabolic cylindrical mirror M ₂ are arranged so that their respective focal points coincide with each other, so the focal point F is a parabolic cylindrical surface. with the focus of the mirror M _1, it is also the focal point of the parabolic cylinder plane mirror M ₂₎ for emitting a parabolic cylindrical surface mirror M ₂ through. The parabolic cylindrical mirror M ₂ has its focal point F (as described above, since the parabolic cylindrical mirror M ₁ and the parabolic cylindrical mirror M ₂ are arranged so that their focal points coincide with each other, The focal point F is the focal point of the parabolic cylindrical mirror M ₂ and is also the focal point of the parabolic cylindrical mirror M ₁ ), and the reflected light 21 emitted from the parabolic cylindrical mirror M ₁ is two-dimensionally emitted. The object image 23 is reflected by the concave side of the object surface and projected onto the image pickup surface portion of the CCD 3.

Here, for example, when a reproduced image having an aspect ratio of 4: 3 is to be obtained, a subject image 2 from the lens unit 1 is obtained.
The aspect ratio of 1 is virtually 4: 3 (= 16: 12)
Therefore, the aspect ratio of 4: 3 (= 16: 12) is applied to the entire imaging surface of the CCD 3 having the aspect ratio of 16: 9.
To project the subject image 21 of, the vertical scale (aspect ratio 16:12 (= 4: 3) 1
2) is the vertical scale of the CCD 3 (aspect ratio 1
It is necessary to match 9) of 6: 9.

Therefore, in FIG. 2, a parabolic cylindrical mirror M ₁
The ratio of the focal length f ₁ of the object parabolic mirror M _{2 to} the focal length f ₂ of the parabolic mirror M ₂ is 4: 3 (= 12: 9). ) Is 3/4 times the scale of the subject image 21 from the lens unit 1 in the vertical direction (vertical direction in the drawing). That is, the scale of the subject image 21 having an aspect ratio of 4: 3 (= 12: 9) in the vertical direction (vertical direction in the drawing) is 3/4 times as large as the subject image 23. Therefore, the aspect ratio of the subject image 23 is 4: 3 × 3/4 = 16: 12 × 3/4 = 16: 9, and the aspect ratio of 16: 9 is applied to the entire imaging surface of the CCD 3 having the aspect ratio of 16: 9. Subject image 23 (FIG. 3)
(B)) is projected as a subject image 21 (FIG. 3A) having an aspect ratio of 4: 3 (= 16: 12).

That is, the aspect ratio converter 2 converts the subject image 21 (FIG. 3A) from the lens unit 1 into a subject image 23 (FIG. 3B) whose vertical scale is expanded or contracted. (The aspect ratio of the subject image 21 is 4: 3 (= 16: 1)
2) is converted to 16: 9) and is projected onto the entire image pickup surface of the CCD 3 having an aspect ratio of 16: 9.

The A / D converter 4 A / D converts the image signal output from the CCD 3 at the timing of the clock signal supplied from the signal generator (SG) 11,
Output to the γ correction circuit 5 and the electronic viewfinder 10. The electronic viewfinder 10 displays an image corresponding to the image signal (digital signal) output from the A / D converter 4 on its screen.

The γ correction circuit 5 performs γ correction on the image signal output from the A / D converter 4, and supplies the image signal to the frame memory 6. The frame memory 6 temporarily stores the image signal (digital signal) output from the γ correction circuit 5 according to the clock signal supplied from the SG 11. The matrix circuit 7 reads out the image signal stored in the frame memory 6 and performs coordinate conversion of its color (chroma) component.
The memory controller 8 writes the image signal output from the matrix circuit 7 in the memory card 9. The memory card 9 is controlled by the memory controller 8 and stores the image signal output from the matrix circuit 7.

The SG 11 generates a clock signal having a predetermined cycle and supplies it to the A / D converter 4, the frame memory 6 and the CCD driver 12. CCD driver 1
2 drives the CCD 3.

Next, the operation will be described. The incident external light is imaged in the lens unit 1 and emitted to the aspect ratio conversion unit 2 (parabolic cylindrical mirror M ₁ ). In the parabolic cylindrical mirror M ₁ (FIG. 2) of the aspect ratio conversion unit 2, the object image 21 from the lens unit 1 having an aspect ratio (virtual aspect ratio) of 4: 3 is a two-dimensional parabolic surface. The reflected light 22 reflected on the concave side passes through the focal point F of the parabolic mirror M.
Emitted to ₂ . In the parabolic cylindrical mirror M ₂ , the reflected light 21 emitted from the parabolic cylindrical mirror M ₁ through its focal point F is 2
The subject image 23 having an aspect ratio of 16: 9 is reflected on the concave side of the three-dimensional paraboloid, and is projected onto the entire imaging surface of the CCD 3 having an aspect ratio of 16: 9.

In the CCD 3, the subject image 23 projected on the entire image pickup surface is photoelectrically converted, converted into an image signal as an electric signal, and output to the A / D converter 4.
In the A / D converter 4, the image signal output from the CCD 3 is A / D converted and output to the γ correction circuit 5 and the electronic viewfinder 10. In the electronic viewfinder 10, an image corresponding to the image signal (digital signal) output from the A / D converter 4 is displayed on the screen.

In the γ correction circuit 5, the image signal output from the A / D converter 4 is subjected to γ correction and supplied to the frame memory 6. The image signal (digital signal) output from the γ correction circuit 5 is temporarily stored in the frame memory 6, and the image signal stored in the frame memory 7 is read out in the matrix circuit 7 to obtain its color (chroma) component. Coordinate conversion is performed. In the memory controller 8, the image signal in which the coordinate conversion of the color components is performed by the matrix circuit 7 is written in the memory card 9.

As described above, the virtual aspect ratio 4:
The subject image 21 of 3 is the CCD 3 with the aspect ratio of 16: 9.
Since photoelectric conversion can be performed by using all the effective pixels of, high-definition images can be stored in the memory card 9.

Further, since the lens unit 1, the aspect ratio conversion unit 2 and the CCD 3 can be arranged as shown in FIG. 4, the lens unit 1 and the CCD 3 are arranged on the same straight line (the CCD 3 is the lens unit). The device can be made more compact than the conventional device (which must be located directly behind the device 1).

In the present embodiment, the parabolic cylindrical mirror M ₁ and the parabolic cylindrical mirror M ₂ of the aspect ratio conversion unit 2 are arranged on the concave side of the two-dimensional parabolic surface of the lens unit 1. Although it is configured (arranged) so as to reflect the emitted light from, the aspect ratio conversion unit 2 can be configured as shown in FIG. 5 in addition to this.

In FIG. 5, the aspect ratio conversion unit 2
Is a parabolic cylindrical mirror M ₁₁ having a convex surface of the two-dimensional parabolic surface as a reflecting surface and a focal length of f ₁₁ and a concave surface of the two-dimensional parabolic surface as a reflecting surface. It is composed of a parabolic cylindrical mirror M ₁₂ having a focal length of f ₁₂ , and the parabolic cylindrical mirror M ₁₁ and the parabolic cylindrical mirror M ₁₂ are arranged so that their respective focal points coincide with each other.

Further, in FIG. 5, a parabolic cylindrical mirror M ₁₁
The ratio of the focal length f ₁₁ of the parabolic mirror M _{12 to} the focal length f ₁₂ of the parabolic mirror M ₁₂ is 3: 4 (= 12: 16). ) Is 4/3 times the scale of the subject image 31 from the lens unit 1 in the vertical direction (vertical direction in the drawing).

Here, the CCD 3 in FIG. 5 is arranged by being rotated by 90 degrees as compared with the arrangement angle in the case of FIG. That is, the CCD 3 is vertically and horizontally reversed as compared with the arrangement in the case of FIG. 1, and the aspect ratio is, so to speak, 9:16.

Therefore, if the vertical and horizontal directions of the subject images 31 and 32 are considered in the opposite manner, the aspect ratio is 3: 4.
The object image 32 is obtained by scaling the vertical direction (vertical direction in the drawing) of the object image 31 of (= 9: 12) by 4/3. Therefore, the aspect ratio of the subject image 32 is 3: 4 × 4/3 = 9: 12 × 4/3 = 9: 16, and the aspect ratio of 9:16 is applied to the entire imaging surface of the CCD 3 having the aspect ratio of 9:16. The subject image 32 is projected as the subject image 31 with an aspect ratio of 3: 4 (= 12: 16).

[0028]

As described above, according to the image pickup apparatus of the present invention, the first focal point-aligned first focal points having different focal lengths are arranged.
Further, the light reflected by the lens means is reflected by the two-dimensional parabolic surface by the second reflecting means and is applied to the image pickup surface portion of the image pickup means for photoelectric conversion. Therefore, by changing the focal length ratios of the first and second reflecting means, the light imaged by the lens means can be projected onto the entire image pickup surface portion of the image pickup means having an arbitrary aspect ratio, which results in high image quality. The image of can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a digital electronic still camera to which an image pickup apparatus of the present invention is applied.

FIG. 2 is a diagram showing a more detailed configuration of an aspect ratio conversion unit 2 of the embodiment shown in FIG.

FIG. 3 is a subject image 2 incident on an aspect ratio converter 2.
2 is a plan view showing 1 and a subject image 23 emitted from the image.

FIG. 4 is a diagram showing an arrangement example of a lens unit 1, an aspect ratio conversion unit 2, and a CCD 3 of FIG.

FIG. 5 is a diagram showing another configuration example of the aspect ratio conversion unit 2.

[Explanation of symbols]

 1 Lens Part 2 Aspect Ratio Converter 3 CCD 4 A / D Converter 5 γ Correction Circuit 6 Frame Memory 7 Matrix Circuit 8 Memory Controller 9 Memory Card 10 Electronic Viewfinder 11 SG (Signal Generator) 12 CCD Driver 21 Subject Image 22 Reflection Light 23, 31, 32 Subject image

Claims (1)

[Claims] 1. Lens means for focusing light, and first and second focal points which are arranged so that their focal points match and which reflect the light focused by the lens means on a two-dimensional parabolic surface. And an image pickup unit that photoelectrically converts the light reflected by the first and second reflection units and outputs an image signal.