JPH09181958A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image with less color slurring and without a shape at a still image photographing mode by restricting correction quantity when a photographing mode is switched to the still image mode. SOLUTION: The displacement 71 of an image pickup device shows a state where the image pickup device is moved in one direction at the same angular velocity for prescribed time. When optical axis correction quantity exceeds the threshold 74 of angular displacement at the time of taking a dynamic image, panning/tilting control is executed and a characteristics shown as optical axis correction quantity 72 at the time of taking the dynamic image is obtained. If optical axis correction quantity exceeds the threshold 75 of angular displacement at the time of taking the still image when the mode is switched from dynamic image photographing to still image photographing, panning/tilting control is executed and the characteristics shown as optical axis correction quantity 73 at the time of photographing the still image is given. Thus, optical axis correction quantity 73 at the time of taking the still image is smaller than optical axis correction quantity 72 at the time of taking the dynamic image even if the image pickup device is similarly moved. Namely, the level of color slip can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device,
In particular, it relates to the correction of blurring (sometimes referred to as blurring).

[0002]

2. Description of the Related Art Conventionally, video cameras have been automated and multifunctional in all respects such as AE (auto exposure) and AF (auto focus), so that good photographing can be easily performed.

Further, in recent years, with the downsizing of video cameras and the increase in magnification of optical systems, attention has been paid to the fact that camera shake is a major cause of deterioration in the quality of captured images, and this camera shake is corrected. Various imaging devices with a blur correction function have been proposed.

FIG. 4 shows an example of the main configuration of a conventional image pickup apparatus with a blur correction function. In the figure, 1 is an angular velocity detector including an angular velocity sensor such as a vibration gyro,
It is attached to an image pickup device with a shake correction function such as a camera. Reference numeral 2 is a DC cut filter that blocks the DC component of the angular velocity signal output from the angular velocity detector 1 and passes only the AC component, that is, the vibration component. As the DC cut filter, a high pass filter (hereinafter referred to as HPF) that cuts off a signal in a predetermined band may be used.

Reference numeral 3 is an amplifier for amplifying the angular velocity signal output from the DC cut filter 2 to an appropriate level (a level at which a required detection sensitivity is obtained).

Reference numeral 4 is an A / D converter that converts the angular velocity signal output from the amplifier 3 into a digital signal, and 5 is a high-pass filter (HPF) that blocks low-frequency components of the output of the A / D converter 4. It has the function of changing the characteristics in any band. Reference numeral 6 denotes an integrator that integrates the output (angular velocity signal) of the HPF 5 and outputs an angular displacement signal, and has a function of changing the characteristics in an arbitrary band. Reference numeral 7 denotes a pan / tilt determination circuit that determines panning / tilting from an integrated signal of the angular velocity signal and the angular velocity signal output from the integrator circuit 6, that is, the angular displacement signal, which will be described later according to the levels of the angular velocity signal and the angular displacement signal. Performs panning and tilting control. Reference numeral 8 denotes a D / A converter that converts the output of the angular displacement signal into an analog signal and outputs it. A / D converter 4, HPF 5, integrator 6, pan / tilt determination circuit 7, D
The / A converter 8 is composed of, for example, a microcomputer (hereinafter referred to as a microcomputer) COM. Reference numeral 9 is a drive circuit for driving the image correcting means in the subsequent stage so as to suppress blurring based on the angular displacement signal output from the microcomputer.
Is an image correction means, and an optical correction means that optically shifts the optical axis to cancel the blur is used.

Here, the operation of the pan / tilt determination circuit 7 will be described in detail. The angular velocity signal output from the A / D converter 4 and the angular displacement signal output from the integrating circuit 6 are input, and even if the angular velocity is equal to or higher than a predetermined threshold value or the angular velocity is within a predetermined threshold value, When the angular displacement signal obtained by integrating the angular velocity signal is equal to or higher than a predetermined threshold value, it is determined that the panning or tilting is performed. In such a case, the low frequency cutoff frequency of the HPF 5 is shifted to the high frequency side, In order to center the correction position of the image correction means gradually to the center of the moving range when the characteristics are changed so that the shake correction system does not respond to the low frequency and panning and tilting are detected. In addition, the time constant of the integration characteristic of the integrator 6 is shifted to a shorter direction, and the value accumulated in the integrator is set to a reference value (a value that can be taken in a state where no shake is detected) (panning Performs tilting control).

During this period, the angular velocity signal and the angular displacement signal are detected, and when the panning and tilting are completed, the low-frequency cutoff frequency is lowered again to extend the blur correction range. Then, the panning and tilting control is exited.

This operation will be described with reference to the flowchart of FIG. 5. # 01 This is the start of this flow and is repeatedly started at a predetermined timing.

# 02 The amplified angular velocity signal is converted from an analog amount into a digital value that can be handled by the microcomputer.

# 03 The HPF is calculated using the value of the cutoff frequency (fc) prepared last time.

# 04 Integral calculation is performed using the value of the time constant prepared last time.

# 05 The integration result, that is, the angular displacement signal is converted into an analog quantity and output.

# 06 It is determined whether the angular velocity signal is equal to or higher than a predetermined threshold value.

# 07 It is judged whether the integrated value is equal to or more than a predetermined threshold value.

Here, if the angular velocity signal is equal to or higher than a predetermined threshold value, or if the integrated value is equal to or higher than the predetermined threshold value even if the angular velocity signal is lower than the predetermined threshold value, it is determined that the panning or tilting state is established. 08, when both the angular velocity signal and the integrated value are less than the predetermined threshold value, the normal control state,
Alternatively, it is determined that the panning and tilting are finished, and the process proceeds to step # 10.

The value of the cutoff frequency used for the # 08 HPF calculation is made higher than the current value by a predetermined value, and the attenuation rate of the low frequency signal is made higher than the current value.

# 09 The value of the time constant used for the integral calculation is made shorter than the current value by a predetermined value so that the angular displacement output approaches the reference value.

The value of the cutoff frequency used for the # 10 HPF calculation is made lower than the current value by a predetermined value, and the attenuation rate of the low frequency signal is made smaller than the current value.

# 11 The value of the time constant used for the integration calculation is made longer than the current value by a predetermined value to enhance the integration effect.

# 12 End of processing.

Next, the image correction means 1 in this conventional example.
An example of 0 is shown in FIG.

In the figure, in particular, a variable apex prism 100 is used, and a voice coil type driving device 11 is used as a driving system.
0 is used, the angular displacement is detected by the encoder 120 and is fed back to the drive system to control the drive amount, thereby forming a closed loop control system.

The variable apex angle prism 100 will be described in detail. Reference numerals 101 and 101 'shown in the figure are flat glasses which are arranged to face each other, and 102 is a transparent inert liquid having a high refractive index (refractive index n). (Or an elastic body), 103 is a sealing material that elastically seals the high-refraction liquid 102 from the outer periphery with a resin film or the like, and 104 is incident on the flat glass 101 at a right angle, and the high-refraction liquid 102 and the flat glass 101 ′ are included. It shows the optical path of light transmitted through.

FIG. 1A shows flat glass 101 and 10
1 ′ is held in parallel, the optical path 104 is incident on the flat glass 101 at a right angle, and the high refractive index liquid 102
And is emitted at a right angle from the flat glass 101 '.

FIG. 1B shows a voice coil type driving device 1
10, the flat glass 101 'is tilted,
It corresponds to a state where the optical optical axis is changed.

In this state, the flat glass 101, 101 '
And the high-refractive-index liquid 102 form an optical prism, so that the light incident on the flat glass 101 at a right angle can change the optical path 104 as shown in the figure when it is emitted from the flat glass 101 '.

In FIG. 1B, the variable apex angle prism 1
00 one of the plane glass 101 'is rotated by an angle σ with respect to the plane glass 101, the passing state of the incident light beam 104' will be further explained. As shown in FIG. The luminous flux 104 ′ thus emitted is deflected by an angle φ = (n−1) σ and emitted according to the same principle as that of the wedge prism. That is, the optical axis 104 'is decentered (deflected) by the angle. Note that σ corresponds to the apex angle of the prism as is clear from the figure. n is a refractive index, which is close to that of glass.

A blur correction operation using the variable apex angle prism 100 will be described with reference to FIG. In the figure, 101'-A and 101'-B are the flat glass described above, 104 and 104 'are optical paths, 150 is an imaging optical system,
Reference numeral 161 is an image pickup device that photoelectrically converts the formed light and outputs it as an electric signal. 162 is a signal processing circuit that converts the electric signal of the image pickup device 161 into a video signal such as NTSC.
A recording device 3 records a video signal.

When the flat glass 101'-A is in parallel as shown in the same figure, the optical path is linearly connected to the image plane as shown by 104, but with an inclination as shown by 101'-B. When it occurs, the optical path changes as shown by 104 ', and it becomes possible to optically correct the movement of the subject, that is, the image blur due to the shake of the image pickup apparatus.

Next, returning to FIG. 6, the drive device, that is, the drive actuator 110 will be described. 111 is a yoke, 112 is a magnet, 113 is a coil, 114 is an arm for transmitting drive torque, and a current is passed through the coil 113. Thus, a voice coil type actuator that can change the apex angle of the variable apex angle prism 100 is configured.

Further, an angular displacement encoder 120 is provided to detect the tilt of the variable vertical angle prism, and 121 is a slit for detecting the angular displacement of the variable vertical angle prism 100, which is a flat glass 101 of the variable vertical angle prism 100. ′ And the arm 114 to rotate through the arm 114 to displace the position. 122 is a light emitting diode for detecting the position of the slit 121, and 123 is a PSD (Position Sensing Det).
ector: an incident light spot position detection sensor utilizing the surface resistance of the photodiode), and the PSD 123 detects the displacement of the slit 121 together with the light emitting diode 122 to detect the angular displacement of the apex angle of the variable apex angle prism 100. Configure the encoder to

The light flux whose optical path is changed by the variable apex angle prism 100 is imaged on the image pickup surface of the image pickup device 161 through the image pickup optical system 150 shown in FIG.

Although not shown in FIG. 6 for convenience of explanation, there is a drive actuator, an encoder and a control device having the same function at right angles to the drive direction of the variable apex angle prism 100, and the light of the image pickup optical system. It is possible to correct blurring vertically and horizontally with respect to the axis.

Next, the basic structure and operation of the control circuit for driving and controlling the variable apex angle prism 100 will be described with reference to the block diagram of FIG. In the figure, 100 is a variable vertical angle prism, 131 is an amplifier, 132 is a driver for driving an actuator, 110 is a voice coil type actuator for driving the above-described variable vertical angle prism, 120
Is an encoder that detects the vertical angle displacement of the variable vertical angle prism,
An adder 134 adds the control signal 133 for blur correction output from the microcomputer CMO and the output signal of the angular displacement encoder 120 with opposite polarities. With this configuration, the control system operates so that the blur correction control signal 133 output from the microcomputer COM and the output signal of the angular displacement encoder 120 become equal.
As a result, the variable apex angle prism 100 is driven so that the output of the encoder 120 matches the control signal 133, so that the variable apex angle prism 100 is controlled at the position (apex angle) indicated by the microcomputer COM.

[0036]

However, when the optical correction means shown in the above-mentioned conventional example is used, optical spectroscopy (dispersion of spectrum) occurs to some extent when performing optical correction. As a result of the correction amount of the correction optical system, color noise (color misregistration) occurs in the contour portion of the captured image.

In particular, in the variable apex angle prism in which the flat glass and the high refractive index liquid described in the above-mentioned conventional example are combined, the spectrum appears remarkably when the optical axis is changed.

In a conventional moving image of a video camera or the like, since the movement of the correction optical system performs the correction operation substantially symmetrically with respect to the correction center (optical axis), the color is affected by the integration effect by the human eye. The gap was reduced and it was not a big problem.

However, in recent years, with the digitization of the image pickup device and the recording device, a device for recording and reproducing a moving image and a still image in the same system has been proposed.

Of course, even in such a system, a blurring correction device is about to be used for the purpose of preventing or reducing the blurring of an image. However, in the case of the conventional optical correction system, color is not recorded in still image recording. The deviation is recorded as it is, which causes a problem that the quality of the captured image is deteriorated.

The present invention has been made under such circumstances, and it is an object of the present invention to provide an image pickup apparatus capable of obtaining an image with little color shift and no blur in the still image shooting mode. is there.

[0042]

In order to achieve the above-mentioned object, in the present invention, an image pickup device is constructed as in the following (1) and (2).

(1) A vibration detecting means for detecting the vibration of the image pickup apparatus, an image correcting means for optically correcting a shake of an image in the image pickup optical system based on the output of the vibration detecting means, and the image correcting means. Image pickup means for picking up the corrected image, shooting mode switching means for switching the shooting mode by the image pickup means between a moving image mode and a still image mode, and the image when the shooting mode is switched to the still image mode by the shooting mode switching means. An image pickup apparatus comprising: a control unit that limits a correction amount of the correction unit.

(2) The image pickup device according to (1), wherein the image correction means comprises a variable apex angle prism.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is in the form of a recording device-integrated image pickup device in which a video camera and a recording device are integrally formed,
Further, the video camera and the recording device may be separately provided, and the video camera and the recording device may be connected to each other in a wired or wireless manner. Furthermore, the monitor on the imaging device itself,
It is also possible to use a display device or a recording device of a device such as a personal computer which inputs a line from the image pickup device without providing the recording device.

Hereinafter, the present invention will be described in detail in the form of an image pickup device integrated with a recording device and using an embodiment in which a variable apex angle prism is used as an image correction means. The image correcting means is not limited to the variable apex angle prism, but may be implemented by using an appropriate optical correcting means such as a lens tilt / shift type.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of the main part of an "imaging device" which is an embodiment.

In the figure, the same components as those of the above-mentioned conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

In the figure, a DC cut filter (or HPF) for cutting off a DC component of a speed signal output from an angular velocity detecting means 1 and an angular velocity detecting means 1 which are angular velocity sensors such as a vibration gyro attached to an image pickup device.
2. With regard to the amplifier 3 for amplifying the angular velocity signal to a predetermined level, the drive circuit 9, and the image correction means 10, those having the same configuration as the above-mentioned conventional example can be used.

Further, reference numeral 13 denotes a recording device not shown in FIG. 4 showing a conventional example, which can record a still image in addition to the conventional recording of a moving image. Reference numeral 11 denotes a recording control switch, which is a switch (shooting mode switching means) for the photographer to switch the shooting state to a moving image or a still image according to his or her intention. Reference numeral 12 is a threshold value changing circuit for changing the threshold values of the angular velocity and the integrated value of the pan / tilt determination circuit 7 to predetermined values according to the state of the recording control switcher 11.

In this embodiment, the recording control switching device 11
Is set on the moving image recording side, the blur correction operation is controlled without any change from the above-mentioned conventional example.

When the recording control switch 11 is switched from moving image recording to still image recording, the recording device 13 switches the recording state from moving image to still image, and at the same time, the image pickup device (not shown) also changes the image pickup state to a state corresponding to the still image. Switch.

At the same time, the information whose recording state has been switched is input to COM and transmitted to the threshold value changing circuit 12. The threshold value changing circuit 12 is a pan / tilt determination circuit 7.
The threshold value of the angular velocity and the threshold value of the integral value are set to predetermined values that are smaller than those at the time of shooting a moving image to facilitate the control of panning or tilting.

This operation will be described with reference to the flowchart of FIG.

# 21 This is the start of this flow and is repeatedly started at a predetermined timing. # 22 It is determined whether the recording control switch 11 is in the moving image recording mode or the still image recording mode.

# 23 In the moving image recording mode, the angular velocity of the pan / tilt determination circuit and the threshold value of the integrated value are the same as those in the conventional example.

Therefore, the correction operation is no different from that of the conventional example.

# 24 In the still image recording mode, the angular velocity of the pan / tilt determination circuit and the threshold value of the integrated value are set to predetermined values smaller than those in the conventional example, and the transition to the panning / tilting control is performed at an early stage. By doing so, the variable apex angle prism 100 is controlled so that the apex angle of the variable apex angle prism 100 does not become small, in other words, the spectrum is not generated much.

# 25 End of processing.

FIG. 3 shows the angular displacement of the optical axis during panning or tilting during moving image recording and still image recording.

The figure shows a graph of the angular displacement of each part when the image pickup apparatus of the embodiment is shaken in a single direction. Further, in this description, the pan / tilt determination circuit makes a determination by increasing the angular displacement (= integrated value). State when performing (Yes in # 07 of FIG. 5)
(When the judgment is made)).

In FIG. 3, reference numeral 71 is an angular displacement (swing) of the image pickup device, and 72 is a moving image shooting (moving image recording mode) at that time.
The angular displacement of the optical axis correction amount at time 73 indicates the angular displacement of the optical axis correction at the time of still image shooting (still image recording mode).

Reference numeral 74 indicates a threshold value of the angular displacement (threshold value of the integral value) at the time of shooting a moving image. When the threshold value is exceeded, the pan / tilt determination circuit 7 determines the panning or the tilting, and the HPF5. The low-frequency cutoff frequency is changed to the high-frequency side, the characteristics are changed so that the shake correction system does not respond to the low-frequency, and the image correction means 1
In order to gradually center the correction position of 0 to the center of the moving range, the time constant of the integration characteristic of the integrator 6 is changed to be shorter, and the value accumulated in the integrator is controlled to be the reference value. .

Reference numeral 75 denotes a threshold value of angular displacement at the time of still image shooting, which is the same panning / tilting threshold value as the threshold value 74 of angular displacement at the time of moving image shooting.

More specifically, the displacement 71 of the image pickup device shows a state in which the image pickup device is shaken in one direction at the same angular velocity for a predetermined time, and the blur correction control at this time is performed by the recording control switcher 11. Is switched to movie shooting,
The threshold value changing circuit 12 takes the threshold value 74 of the angular displacement at the time of shooting a moving image which is a conventional threshold value, and when the optical axis correction amount exceeds the threshold value 74 of the angular displacement at the time of shooting a moving image, panning /
Entering tilting control, the amount of optical axis correction when shooting a movie is 7
The characteristics shown in 2 are obtained.

When the recording control switch 11 is switched from moving image shooting to still image shooting, the threshold value changing circuit 1
2 is a new threshold value of the angular displacement threshold value 75 at the time of still image shooting, and when the optical axis correction amount exceeds the angular displacement threshold value 75 at the time of still image shooting as in the case of moving image shooting. , The panning / tilting control is entered, and the optical axis correction amount at the time of shooting a still image has the characteristic indicated by 73.

Therefore, the graph 7 of the optical axis correction amount in FIG.
As can be seen from Nos. 2,73, the optical axis correction amount during still image shooting is smaller than the optical axis correction amount during moving image shooting even when the imaging device is similarly shaken, in other words, the level of color misregistration can be reduced. I can say.

Further, in this embodiment, the panning and tilting control are changed by changing the threshold value of the integrated value (= angular displacement), but similarly, the threshold value of the angular velocity is also changed so that the large angular velocity is fluctuated. On the other hand, it is also possible to limit the correction amount of the variable apex angle prism.

As described above, according to the present embodiment,
When switching to the still image recording mode, there is little color shift,
A good image without blurring can be recorded.

[0070]

As described above, according to the present invention,
In the still image recording mode, it is possible to obtain a good image with little color shift and no blur.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a main part of an embodiment.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 is a diagram showing changes in the optical axis correction amount during panning and tilting in the example.

FIG. 4 is a diagram showing a configuration of a main part of a conventional example.

FIG. 5: Flow chart for panning and tilting determination

FIG. 6 is a diagram showing the configuration and operation of a variable apex angle prism.

FIG. 7 is a diagram showing a blur correction operation by a variable apex angle prism.

FIG. 8 is a block diagram showing a configuration for controlling a variable apex angle prism.

[Explanation of symbols]

 1 Gyro 7 Pan / Tilt Judgment Circuit 10 Image Corrector 11 Recording Control Switch 12 Threshold Change Circuit

Claims (2)

[Claims] 1. A vibration detecting means for detecting a vibration of an image pickup apparatus, an image correcting means for optically correcting a blur of an image of an image pickup optical system based on an output of the vibration detecting means, and a correction by the image correcting means. Image pickup means for picking up the captured image, shooting mode switching means for switching the shooting mode of the image pickup means between the moving image mode and the still image mode, and the image correction when the shooting mode is switched to the still image mode by the shooting mode switching means An image pickup apparatus comprising: a control unit that limits a correction amount of the unit. 2. The image pickup apparatus according to claim 1, wherein the image correction means includes a variable apex angle prism.