JP3592007B2 - Imaging device and lens unit - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an imaging device and a lens unit, and more particularly, to an imaging device and a lens unit having a function of correcting shake such as camera shake or vibration.
[0002]
[Prior art]
In a small video camera or the like, the subject image is often blurred due to camera shake, vibration, or the like, resulting in an unsightly image. In particular, since a high-magnification lens has been adopted recently, there has been a problem that blurring is noticeable on the telephoto side.
[0003]
In view of the above, a large number of shake correction devices for correcting the shake such as the hand shake have been proposed and commercialized. As a shake correction method using an optical system, there is a conventional example in which an angular velocity sensor is used as shake detection means, and a variable angle prism (VAP) is used as image correction means. Hereinafter, this will be described.
[0004]
First, VAP will be described. As shown in FIG. 2, two glass plates 21 and 22 facing each other, bellows 23 and 24 connecting the two glass plates, and a high refractive liquid filling a space sealed by the two glass plates and the bellows. 25. The glass plates 21 and 22 are provided with rotating shafts 26 and 27, respectively.
[0005]
In FIG. 2, the incident light beam 28 when one glass plate 21 is rotated by σ about the rotation axis 26 is deflected by φ according to the same principle as the wedge prism. Similarly, the other glass plate 22 is configured to rotate about a rotation axis 27 and deflect an incident light beam 28.
[0006]
The variable apex prism configured as described above removes the blur of the subject image by controlling the two glass plates 21 and 22 simultaneously. In this example, when filtering the signal of the angular velocity sensor, first, a DC component is cut off by a DC cutoff filter, a predetermined amount is amplified for camera shake correction, and then the predetermined angle is filtered to perform the variable apex angle. This is the target value of the prism apex angle. The camera shake correction is performed by varying the apex angle of the VAP described above according to the target value.
[0007]
[Problems to be solved by the invention]
However, the sensitivity of the signal of the angular velocity sensor becomes lower as the frequency becomes lower, and the phase of the low frequency band is not ideal due to the signal processing. There was a problem.
[0008]
Therefore, it is conceivable to detect the movement of the image between the fields from the photographed image and improve the low-frequency performance by using the movement information of the image together. However, in this case, since the sampling period of the image motion detection is slow, if the target value is updated in that period, the image will have a reduced resolution.
[0009]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to prevent a decrease in resolution when correcting an image using motion information of the image.
[0010]
[Means for Solving the Problems]
An image pickup apparatus according to the present invention includes a shake detection unit that detects a shake of a device, a movement detection unit that detects a movement of an image from an image signal, an output signal of the shake detection unit and an output signal of the movement detection unit, A signal for calculating a correction target value of the shake correcting means from a motion vector signal detected by the shake detecting means for optically correcting the shake of the image in accordance with one of the output signals; Processing means, and a sampling cycle variable means for making a sampling cycle of a correction target value calculated by the signal processing means faster than a sampling cycle of the motion vector signal, wherein a lens unit including the shake correcting means is detached from a camera body. It is freely configured and replaceable, and the sampling cycle variable means is provided in the lens unit. It is characterized in Rukoto.
[0011]
According to another feature of the imaging apparatus of the present invention, the shake detecting unit includes an angular velocity detecting unit and a second signal processing unit that converts an angular velocity signal into an angular displacement signal. I have.
[0012]
Another feature of the image pickup apparatus of the present invention is that the shake correcting means is a shake correcting means for optically correcting a shake, and is a variable apex angle prism.
[0013]
Another feature of the image pickup apparatus of the present invention is that the shake detecting means detects the shake of the device by using two orthogonal components.
[0014]
The lens unit of the present invention is a lens unit that can be attached to and detached from an imaging device, and includes a shake detection unit that detects a shake of the imaging device, and a motion vector component in an image signal detected on the imaging device side. A shake correction means for optically correcting the shake of an image based on one or both of the output signals of the shake detection means, and a correction target value of the shake correction means calculated and supplied based on the motion vector. And a sampling cycle varying means for making the sampling cycle faster than the sampling cycle of the motion vector and providing the same to the shake correcting means.
[0015]
Another feature of the lens unit of the present invention is that the shake detecting means is constituted by an angular velocity sensor, and the shake correcting means is constituted by a shake correcting means for optically correcting the movement of an image. It is characterized by.
[0024]
[Action]
The present invention comprises the above technical means, and provides a sampling cycle variable means in the lens unit for making the sampling cycle of the correction target value faster than the sampling cycle of the image motion vector signal. When used together to improve low-frequency performance, it is possible to prevent the disadvantage that the resolution is reduced due to the slow sampling cycle of the correction target value given to the shake correction means, and to sample the image motion vector signal. The period can be optimally converted according to the magnification of the lens unit.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an imaging device and a lens unit of the present invention will be described with reference to the drawings.
(1st Embodiment)
FIG. 1 shows the configuration of the first embodiment.
In FIG. 1, an output of an angular velocity sensor 101 for detecting a shake is supplied to a DC cut filter 102 to cut a DC component, and is amplified to a predetermined level by an amplifier 103.
[0027]
The amplified signal is supplied to a signal processing circuit 105 to perform signal processing necessary for calculating a first target value of the VAP apex angle.
On the other hand, the VAP unit 108 is provided with an apex angle sensor 110 for detecting the apex angle, and the output of the apex angle sensor 110 is amplified by a predetermined amount by the amplifier 109.
[0028]
Next, the difference between the first target value, which is the output of the signal processing circuit 105, and the output of the amplifier 109 is taken as a control amount, and is input to the drive circuit 106. Then, the drive circuit 106 drives the actuator 107 in the VAP unit 108 that changes the apex angle of VAP. With this series of operations, shake such as hand touch is optically corrected.
[0029]
However, in the operation described above, the sensitivity of the output signal of the angular velocity sensor 101 becomes lower as the frequency becomes lower, and the phase of the low frequency band is not ideal due to the signal processing. There is a problem that the shake correction ability gives an impression that the effect is poor. In the present embodiment, the correction capability is improved as follows.
[0030]
That is, the solid-state imaging device 111 converts an image via the optical system into an electric signal (hereinafter, referred to as an image signal) while being controlled by the solid-state imaging device drive control circuit 115. This video signal is subjected to predetermined signal processing by an analog signal processing circuit 112, and is further converted to a digital signal by an analog / digital conversion circuit (A / D conversion circuit) 113. Then, the video signal converted into the digital signal is supplied to a recording system and a finder system, and is also sent to an image motion detection circuit 114, which is used to detect an image motion vector indicating the amount of image motion between fields. I have.
[0031]
A second target value of the VAP apex angle is calculated from the image motion vector detected by the image motion detection circuit 114 via the integrator 119, the HPF 118, the second integrator 117, and the DA converter 116. Note that the DA converter 116 has a function of holding an output value until data is updated.
[0032]
Since the image motion vector has a higher low-band detection capability than the angular velocity sensor, the second target value calculated as described above is added to the first target value to improve the low-band detection capability. I try to make it.
[0033]
At this time, since the sampling cycle of the image motion detection is slow, updating the second target value in that cycle results in an image having a reduced resolution. Thus, in the present embodiment, for example, in the case of the NTSC system, the second target value is added to the above-described first target value at a cycle of 120 Hz. The value to be interpolated is calculated by the interpolation circuit 120.
[0034]
Next, the operation of the interpolation circuit 120 will be described with reference to the flowchart of FIG. Here, the case of the NTSC system will be described.
Since the image motion vector detects motion between fields, the second integrator 117 operates 60 times per second. The process 301 is started with the end of the calculation as a trigger.
[0035]
Next, in a process 302, a difference between the previous integral value held in the memory Z is obtained from the integral value, and a half thereof is added to the integral value and stored in the memory H. Here, the integral value is an output value of the second integrator 117.
[0036]
Next, the integral value is stored in the memory Z by the process 303. Here, the value stored in the memory Z is used next time.
Next, in step 304, it is determined whether 1/120 second has elapsed from step 301, and if it has elapsed, the process proceeds to step 305. The interpolation circuit 120 has a counter function, and counts 1/120 seconds using the counter function. Next, the value of the memory H is output to the DA converter 116 by the process 305.
[0037]
The difference in the manner of changing the target value actually output from the DA converter 116 by the above-described interpolation circuit 120 will be described with reference to FIG.
FIG. 4A is an example of the timing at which the target value changes when there is no interpolation circuit 120, and one division on the time axis is 1/60 second.
This is as shown in FIG. 4B by the operation of the interpolation circuit 120. One division on the time axis is 1/120 second.
[0038]
Accordingly, in the optical camera shake correction function, when the signal from the motion detection means is used in combination to improve the performance in the low frequency range, the sampling cycle of the correction target value given to the VAP unit as the vibration correction means is slow. Can solve the problems that occur. Although the correction function is described as one system here, there are actually two systems in the vertical and horizontal directions.
[0039]
(Second embodiment)
FIG. 5 shows the configuration of a second embodiment of the imaging apparatus according to the present invention.
As shown in FIG. 5, the imaging apparatus according to the present embodiment includes a lens unit 218 and a camera body 228.
[0040]
In the lens unit 218 shown in FIG. 5, the output of the angular velocity sensor 201 for detecting the shake is cut off the DC component by the DC cut filter 202 and is amplified by the angular velocity signal amplifier 203 by a predetermined amount.
[0041]
Then, the amplified signal is supplied to the angular velocity signal processing circuit 204 to perform signal processing necessary for calculating the first target value of the VAP apex angle.
On the other hand, the VAP unit 207 has a vertex angle sensor 214 for detecting a vertex angle, and the output is amplified by a vertex angle signal amplifier 213 by a predetermined amount.
[0042]
Next, the difference between the first target value output from the angular velocity signal processing circuit 204 and the output from the apex angle signal amplifier 213 is taken as a control amount, and input to the drive circuit 205. The drive circuit 205 drives an actuator 206 that changes the apex angle of VAP according to the input control amount. With this series of operations, the shake is optically corrected.
[0043]
However, the signal of the angular velocity sensor 201 has lower sensitivity as the frequency becomes lower, and the phase of the low frequency band is not ideal due to the signal processing. Makes an impression.
[0044]
The solid-state imaging device 220 is controlled by the solid-state imaging device drive control circuit 223, and converts an image input via the optical systems 208 to 212 into an electric signal (hereinafter, referred to as an image signal). This video signal is subjected to signal processing by an imaging signal processing circuit 221 and further converted to a digital signal by an analog-to-digital conversion circuit (A / D conversion circuit) 222.
[0045]
The video signal converted into the digital signal is supplied to a recording system and a finder system, and is also sent to an image motion detection circuit 224, and detects an image motion vector indicating a motion amount of an image between fields.
[0046]
The image motion vector detected by the image motion detection circuit 224 is supplied to the lens microcomputer 215 in the lens unit 218 via the integrator 227, the HPF 226, and the second integrator 225, and the D / A conversion provided there is provided. Via the circuit 216, the second target value of the VAP vertex angle is set. Note that the D / A conversion circuit 216 has a function of holding an output value until data is updated.
[0047]
Since the image motion vector has a higher detection capability in the low frequency range than the angular velocity sensor, the sampling period of the image motion detection is slow when adding the second target value to the first target value. When the second target value is updated, an image having a reduced resolution is obtained. Therefore, for example, in the case of the ENTSC system, the second target value is added to the above-described first target value at a cycle of 120 Hz. The value to be interpolated is calculated by the interpolator 217.
[0048]
The difference between the operation of the interpolator 217 and the manner of changing the target value output from the D / A conversion circuit 216 is as described with reference to FIG. 4 in the first embodiment. Detailed description is omitted in the embodiment.
[0049]
Note that the present invention may be applied to a system including a plurality of devices or to an apparatus including a single device. Needless to say, the present invention is also applicable to a case where the present invention is implemented by supplying a program to a system or an apparatus.
[0050]
In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to a system or an apparatus, the system or the apparatus operates in a predetermined method.
[0051]
【The invention's effect】
According to the present invention, the sampling period varying means for making the sampling period of the correction target value faster than the sampling period of the image motion vector signal is provided in the lens unit. In the case of using the signals from both, the problem that occurs due to the slow sampling cycle of the correction target value given to the shake correction means can be solved, the shake correction without lowering the resolution can be performed, and even if the lens unit is replaced It is easy to optimally convert the sampling period of the image motion vector signal according to the lens unit.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a first embodiment of an imaging device according to the present invention.
FIG. 2 is a diagram illustrating the configuration and operation of a variable apex angle prism.
FIG. 3 is a flowchart illustrating an operation of an interpolation circuit in the first embodiment.
FIG. 4 is a characteristic diagram for explaining an operation of an interpolation circuit in the first embodiment.
FIG. 5 is a block diagram illustrating a configuration of a second embodiment of the imaging apparatus according to the present invention.
[Explanation of symbols]
101 angular velocity sensor 102 DC cut filter 103 amplifier 105 signal processing circuit 106 drive circuit 107 actuator 108 VAP unit 109 amplifier 110 apex angle sensor 111 solid-state imaging device 112 analog signal processing circuit 113 analog-to-digital conversion circuit 114 image motion detection circuit 115 solid-state imaging device Drive control circuit 116 DA converter 117 Second integrator 118 HPF
119 integrator 120 interpolation circuit

Claims (6)

A shake detecting means for detecting a shake of the device,
Motion detection means for detecting the motion of the image from the image signal;
An output signal of the shake detection unit and an output signal of the motion detection unit, or a shake correction unit that optically corrects a shake of an image, according to one of the output signals,
Signal processing means for calculating a correction target value of the shake correction means from a motion vector signal detected by the motion detection means;
Sampling cycle variable means for making the sampling cycle of the correction target value calculated by the signal processing means faster than the sampling cycle of the motion vector signal,
An imaging apparatus, wherein a lens unit including the shake correction unit is configured to be detachable from a camera body and is replaceable, and the sampling cycle variable unit is provided in the lens unit. The imaging device according to claim 1,
The image pickup apparatus according to claim 1, wherein said shake detecting means includes an angular velocity detecting means and a second signal processing means for converting the angular velocity signal into an angular displacement signal. The imaging device according to claim 1,
The image pickup apparatus, wherein the shake correcting means is a shake correcting means for optically correcting a shake, and is a variable apex angle prism. The imaging device according to claim 1,
The image pickup apparatus according to claim 1, wherein the shake detecting means detects a shake of the device using components in two orthogonal directions. A lens unit detachable from the imaging device,
Shake detection means for detecting shake of the imaging device;
A motion vector component in an image signal detected on the imaging device side, and a shake correction unit for optically correcting image shake based on one or both output signals of the shake detection unit,
And a sampling cycle varying unit that calculates a correction target value of the shake correction unit that is calculated based on the motion vector and that is supplied to the shake correction unit by making the sampling period faster than the sampling period of the motion vector. Characteristic lens unit. The lens unit according to claim 5,
A lens unit, wherein the shake detecting means is constituted by an angular velocity sensor, and the shake correcting means is constituted by shake correcting means for optically correcting the movement of an image.

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