JP2000019576A - Still image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To pick up an image having higher quality than heretofore in a still image pickup device. SOLUTION: After image pickup instruction (S5) is inputted, and when the optical axis directions of optical systems 2 and 3 are aligned with an object direction, an object image transmitted through the optical system is picked up by image pickup means 4 and 5. Thus, chromatic aberration and the deterioration of contrast reproducibility caused when the optical axis of the optical system is bent can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a still image pickup apparatus, and is preferably applied to, for example, a digital camera.

[0002]

2. Description of the Related Art Conventionally, a digital camera supplies light incident from a subject to an image pickup device through an optical system, converts the light into an electric signal, and records the electric signal on a predetermined recording medium. ing.

[0003] By the way, such a digital camera is
At the time of shooting, it is often held by the user's hand. In this case, the digital camera vibrates according to the camera shake of the user, and its operation becomes unstable. Such a camera shake caused by the user at the time of photographing causes deterioration of the quality of an image to be captured. Therefore, a digital camera is provided with a means for optically correcting the camera shake.

Specifically, in a digital camera,
An optical axis variable prism capable of changing the angle of the optical axis is provided at the front stage of the optical system, and a detecting means for detecting the amount of camera shake of the user is provided at a predetermined position, and the amount of camera shake detected by this detecting means is The camera shake is corrected by changing the optical axis of the variable optical axis prism accordingly.

[0005]

In a digital camera having such a configuration, camera shake often occurs at the time of image capturing. Therefore, when a user presses a shutter button, the optical axis accidentally moves from the subject. Except in the same direction as the light, i.e. the optical axis is in the center,
Usually, there is a high possibility that a still image captured in a state where the optical axis is bent is recorded. Light incident from a subject has chromatic aberration indicating the shift of the focal position due to the wavelength and the reproducibility of the lens contrast when the optical axis of the variable optical axis prism is bent, compared to when the optical axis is at the center. Degree of modulation in the signal amplitude direction (MTF: Modulation Transfer Function)
Is deteriorated, so that it is difficult to capture a high-quality still image.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a still image pickup apparatus capable of picking up a still image of higher image quality as compared with the related art.

[0007]

According to the present invention, there is provided a still image pickup apparatus for picking up an object image incident through an optical system by an image pickup means.
Optical axis variable means for changing the optical axis direction of the optical system, camera shake amount detecting means for detecting the camera shake amount of the still image pickup device, and light of the optical system by the optical axis variable means based on the detection result of the camera shake amount detecting means. A camera shake correction unit that constantly captures an object image incident via the optical system by changing the axis, and an optical system when the optical axis direction of the optical system matches the object direction after an imaging command is input. And imaging control means for imaging the subject image transmitted through the imaging means by the imaging means.

When the optical axis direction of the optical system is coincident with the object direction after the imaging command is input, the image of the subject transmitted through the optical system is taken by the image pickup means so that the optical axis of the optical system is bent. Chromatic aberration and MTF deterioration that occur in the image can be avoided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a digital camera as a whole, which captures and records a still image. First, an incident light L1 incident from a subject is passed through an optical axis variable prism 2 which is a predetermined optical component to an optical system 3.
Is incident on. The optical axis variable prism 2 changes the angle of the optical axis according to the amount of camera shake of the digital camera 1 main body, and optically corrects camera shake by the user.

The optical system 3 condenses the incident light L1 to form a subject image on a solid-state image pickup device (CCD: Charge Coupler).
ed Device) 4. The CCD 4 generates an image signal S1 by receiving the incident light L1, and outputs the image signal S1 to the camera signal processing unit 5. Camera signal processing unit 5
Converts the image signal S1 into a predetermined data format and outputs it to the recording unit 6 as an image signal S2. The recording unit 6 records the image signal S2 on a predetermined recording medium containing the image signal S2.

On the other hand, the camera shake amount detection unit 7 comprises an acceleration sensor, detects the movement of the user's hand during imaging, that is, the camera shake amount S3 of the main body of the digital camera 1, and outputs this to a CPU (Central Processing Unit) 8. I do. C
The PU 8 controls the entire digital camera 1 by multitask processing, and calculates the angle of the optical axis of the optical axis variable prism 2 based on the detected camera shake amount S3 while controlling the above-described imaging operation. This is output to the prism drive unit 9 as optical axis angle information S4.

The prism driving section 9 receives the optical axis angle information S
By operating the optical axis variable prism 2 based on the optical axis 4, the angle of the optical axis is changed based on the optical axis angle information S4, and the camera shake by the user is optically corrected.

As shown in FIG. 2, the angle of the optical axis represented by the optical axis angle information S4 changes every moment as the camera shake amount S3 changes over time. In this state, when the shutter button 10 is pressed by the user, the shutter button 10 generates a trigger signal S5 indicating an imaging command, and outputs this to the CPU 8. When detecting that the trigger signal S5 has been supplied, the CPU 8 determines that the optical axis direction coincides with the subject direction, that is, the angle of the optical axis is “0”.
The timing (for example, times t1 and t4) at which the optical axis angle information S4 and the control signals S6A and S6B are generated based on this timing.

By the way, the prism driving section 9 stores in advance a reference value for positioning the angle of the optical axis of the optical axis variable prism 2 at "0" degrees. Accordingly, the CPU 8 supplies the optical axis angle information S4 having an angle of “0” degree to the prism driving unit 9 to drive the prism driving unit 9,
The angle of the optical axis of the optical axis variable prism 2 is controlled to “0” degrees. At the same time, the CPU 8 supplies the control signal S6A to the camera signal processing unit 5 and the control signal S6B to the recording unit 6, thereby converting the image signal S1 captured when the angle of the optical axis is “0” degree. The data is transferred from the camera signal processing unit 5 to the recording unit 6 and recorded on a recording medium.

Here, the still image capturing procedure by the CPU 8 will be described with reference to the flowchart shown in FIG. First, in step SP2 entered from step SP1, C
When the shutter button 10 is pressed by the user, the PU 8 is supplied with the trigger signal S5 from the shutter button 10 and detects this. In step SP3,
The CPU 8 acquires the camera shake amount S3 detected by the camera shake amount detection unit 7.

In step SP4, the CPU 8 calculates the angle of the optical axis of the optical axis variable prism 2 based on the camera shake amount S3. In step SP5, the CPU 8 determines whether the calculated angle of the optical axis is “0” degree, and as a result,
When it is determined that the angle of the optical axis is “0” degrees, the process proceeds to step SP6, and when it is determined that the angle is not “0” degrees, the process proceeds to step SP3 to repeat the operation.

Then, in step SP6, the CPU 8
Controls the camera signal processing unit 5 and the recording unit 6 to transfer the image signal S1 captured when the angle of the optical axis is “0” degrees from the camera signal processing unit 5 to the recording unit 6. Record. Next, the process moves to step SP7 and ends.

In the above configuration, the CPU 8 controls the camera shake amount S3 detected by the camera shake amount detection unit 7 during imaging.
The angle of the optical axis of the variable optical axis prism 2 is calculated based on the above formula, and the calculated angle is applied to the prism driving unit 9 to operate the variable optical axis prism 2, thereby changing the angle of the optical axis and optically reducing camera shake. Has been corrected.

In this state, when the user presses the shutter button 10, the CPU 8 detects a timing at which the calculated angle of the optical axis becomes “0”, and the angle of this optical axis becomes “0”. The image signal S1 picked up at the timing is recorded.

By the way, in the digital camera 1,
If the user shoots while avoiding camera shake, there is always a timing at which there is no camera shake, that is, the angle of the optical axis becomes “0”. Therefore, after the shutter button 10 is pressed, the digital camera 1 waits until the angle of the optical axis becomes “0”, and records a still image captured when the angle of the optical axis becomes “0”. By doing so, when the optical axis of the variable optical axis prism 2 is bent, it is possible to prevent the chromatic aberration and MTF from being degraded by the variable optical axis prism 2,
Thus, a high-quality still image can be captured.

As described above, the digital camera 1 constantly monitors the angle of the optical axis and records a still image taken when the angle of the optical axis is "0". At time t1 or t1 shown in FIG.
There is no recording of the still image taken at the timing 3, that is, when the optical axis is bent, so that the chromatic aberration and MTF are not degraded by the optical axis variable prism 2.

According to the above configuration, the shutter button 1
After 0 is pressed, the apparatus waits until the angle of the optical axis of the optical axis variable prism 2 becomes “0”, and records a still image captured when the angle of the optical axis becomes “0”. Accordingly, it is possible to avoid chromatic aberration and MTF deterioration that occur when the optical axis of the optical axis variable prism 2 is bent, and thus it is possible to capture a high-quality still image.

In the above-described embodiment, after the shutter button 10 is pressed, the apparatus waits until the angle of the optical axis of the optical axis variable prism 2 becomes "0", and the angle of the optical axis becomes "0". However, the present invention is not limited to this, and when the shutter button 10 is pressed, the angle of the optical axis is forcibly set to “0”. Even if a still image captured at this time is recorded, the same effect as in the above case can be obtained.

Such a still image capturing procedure will be described with reference to a flowchart shown in FIG. First, step SP10
In step SP11, when the shutter button 10 is pressed by the user, the CPU 8 supplies a trigger signal S5 from the shutter button 10 and detects this. In step SP12, CP
U8 forcibly sets the angle of the optical axis of the optical axis variable prism 2 to “0” degrees.

In step SP13, the CPU 8
By controlling the camera signal processing unit 5 and the recording unit 6, the image signal S1 captured when the angle of the optical axis is “0” degrees is transferred from the camera signal processing unit 5 to the recording unit 6 and recorded. . In step SP14, the CPU 8 calculates the angle of the optical axis based on the camera shake amount S3 detected by the camera shake amount detection unit 7, gives this to the prism drive unit 9, and operates the optical axis variable prism 2 to The camera shake is corrected optically by changing the angle of the optical axis. Next, the process moves to step SP15 and ends.

Also, in the above-described embodiment, the case where the present invention is applied to the digital camera 1 has been described. However, the present invention is not limited to this. The present invention can be widely applied to various other still image capturing apparatuses having a function of correcting.

[0028]

As described above, according to the present invention, when an optical axis direction of an optical system coincides with an object direction after an imaging command is input, an object image transmitted through the optical system is imaged by the imaging means. Accordingly, it is possible to avoid chromatic aberration and deterioration in contrast reproducibility that occur when the optical axis of the optical system is bent, and thus it is possible to capture a much higher quality image than in the related art.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a digital camera according to the present invention.

FIG. 2 is a schematic diagram illustrating an angle change of an optical axis.

FIG. 3 is a flowchart illustrating a still image capturing procedure.

FIG. 4 is a flowchart showing a still image capturing procedure according to another embodiment.

[Explanation of symbols]

1 ... digital camera, 2 ... variable optical axis prism, 3
…… optical system, 4 …… CCD, 5 …… camera signal processing unit,
6 recording unit 7 camera shake amount detection unit 8 CPU
9 ... Prism drive unit, 10 ... Shutter button.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeki Ishizuka 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term (reference) 2H054 AA01 5C022 AA13 AB55 AB62 AB63 AB64 AC00 AC32 AC51 AC52

Claims (4)

[Claims] 1. A still image pickup apparatus for picking up an object image incident through an optical system by an image pickup means, wherein: an optical axis variable means for changing an optical axis direction of the optical system; A camera shake amount detecting means for detecting the object image incident through the optical system by changing the optical axis of the optical system by the optical axis variable means based on the detection result of the camera shake amount detecting means. A camera shake correction means which is always taken into the image pickup means, and an image pickup means for picking up an object image transmitted through the optical system by the image pickup means when an optical axis direction of the optical system coincides with the object direction after an image pickup command is input. A still image pickup device comprising a control unit. 2. The image pickup control means waits until the optical axis direction of the optical system coincides with the object direction after the image pickup command is input, and sets the optical axis direction of the optical system in the object direction. 2. The still image pickup apparatus according to claim 1, wherein when detecting that the image coincides with the image, an object image transmitted through the optical system is picked up at this timing. 3. The still image according to claim 1, wherein the camera shake compensator forcibly causes the optical axis direction of the optical system to coincide with the subject direction after the imaging command is input. Imaging device. 4. An image pickup device, comprising: an image pickup device for picking up the subject image formed by the optical system; and a signal processing unit for converting an image signal picked up by the image pickup device into a predetermined data format. The still image capturing apparatus according to claim 1, 2 or 3, further comprising: