JPH11331681A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image pickup device that corrects properly a photographed image with respect to vibration in the case of using the image pickup device as an on-vehicle camera. SOLUTION: The image pickup device 1 is provided with image pickup means 2, 3 that photograph an object, a vibration detection means 7 that detect vertical vibration of a vehicle, a distance calculation means 2a that calculates a distance up to the object, and video output correction means 10, 11, 5 that apply correction processing to an output video image based on the detection result of the vibration detection means 7 and the calculation result of the distance calculation means 2a as to the video signal generated by the image pickup means 2, 3.

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 for a vehicle-mounted camera which is mounted in a vehicle and picks up an object outside the vehicle.

[0002]

2. Description of the Related Art In recent years, imaging devices such as video cameras have become widespread and widely used, and their uses and methods of use have been diversified. In recent years, imaging devices have been installed in vehicles such as automobiles, for example, as in-vehicle cameras, so that powerful images can be taken of external subjects that relatively move while the vehicle is running, or police have arrested criminal offenders. It is used for purposes such as shooting evidence videos for

[0003]

By the way, when an imaging device such as a video camera is used as a vehicle-mounted camera,
There has been a problem that an image at the time of shooting is shaken by vertical vibration generated when a vehicle or the like travels. For vehicles such as automobiles, their suspensions are becoming more sophisticated year by year,
Many of them have excellent characteristics in absorbing vibration, but cannot completely absorb vibration. For this reason,
When photographing an external subject with a vehicle-mounted camera while the vehicle is traveling, vibrations mainly in the vertical direction are generated when the vehicle travels on a road with a lot of unevenness, and the photographed image is shaken.

[0004] Recently, an image pickup apparatus having a camera shake correction function has been widely used. This camera shake correction function is to detect the amount of shaking in a certain direction by an angular velocity sensor, for example, at an angular velocity, and to perform optical or electrical correction on an image to be shot in accordance with the detection result.

[0005] However, since the camera shake correction function is based on the premise that the imaging device is used by hand, good results cannot be obtained when the imaging device is used as a vehicle-mounted camera. There was a problem that would shake. Specifically, the camera shake correction function of the imaging apparatus calculates a shake amount from the angular velocity in two axial directions with the wrist as a fulcrum when the camera body is gripped by hand, and performs imaging based on the calculation result. The correction was performed on the image. Therefore, even if the image pickup apparatus has a camera shake correction function, if the image pickup apparatus is used as an in-vehicle camera, it is necessary to correctly calculate a shake amount with respect to a vertical vibration mainly generated when an automobile or the like travels. As a result, there has been a problem that the correction of the photographed image cannot be appropriately performed.

The present invention has been proposed in view of such circumstances, and when used as an on-vehicle camera,
It is an object of the present invention to provide an imaging device capable of performing appropriate correction for vibration of a vehicle.

[0007]

According to the present invention, there is provided an image pickup apparatus mounted in a vehicle for picking up an image of an object outside the vehicle. A vibration detecting means for detecting a vertical vibration of the vehicle, a distance calculating means for calculating a distance to a subject, and a video signal generated by the imaging means, based on a detection result of the vibration detecting means and a calculation result of the distance calculating means. hand,
Video output correction means for performing a correction process on the video to be output.

[0008] In the image pickup apparatus, the image output correction means, based on the detection result of the vibration detection means and the calculation result of the distance calculation means, for the image signal generated by the image pickup means.
A correction process is performed on the output video.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an imaging apparatus to which the present invention is applied will be described in detail with reference to the drawings. As shown in FIG. 1, an imaging device 1 includes an optical system 2 for inputting imaging light of a subject, a CCD imager 3 for converting the imaging light from the optical system 2 into an electric signal, and an imaging light from the CCD imager 3. A camera signal processing circuit 4 for performing a predetermined process on the electric signal, a video correction circuit 5 for performing a correction process on the processed signal from the camera signal processing circuit 4, and a predetermined process for performing a predetermined process on the signal from the video correction circuit 5. An encoder circuit 6 that outputs an analog video signal is provided. The imaging device 1 includes an acceleration sensor 7 that detects vibration in a certain direction, an integration circuit 8 that integrates a detection signal from the acceleration sensor 7 twice, an acceleration sensor 7 and an integration circuit 8.
An offset canceling circuit 9 for removing the offset caused by the above, a correction angle conversion circuit 10, and a correction amount conversion circuit 11 are provided.

The optical system 2 includes a plurality of optical lenses (not shown), a focus mechanism 2a for driving each optical lens, a zoom mechanism 2b, and the like. In the optical system 2, the imaging light of the subject is transmitted to the CCD imager 3 through each optical lens.
The focus mechanism 2a supplies the information of the focal length to the subject to the correction angle conversion circuit 10, and the zoom mechanism 2b supplies the information of the zoom magnification to the correction amount conversion circuit 11.
To each supply.

The CCD imager 3 includes a CCD (Charge Coupled Device) as an image pickup device,
It comprises a CCD driving circuit for driving this CCD. This C
The CD imager 3 converts the imaging light from the optical system 2 into the CC
The light is received by the light receiving surface 3a where D is arranged, and the received imaging light is converted into an electric signal by a CCD drive circuit and output to the camera signal processing circuit 4.

The camera signal processing circuit 4 receives the input CCD.
Sampling and holding to the electric signal from the imager 3, A /
A digital imaging signal is generated by performing processing such as D conversion, and the digital imaging signal (hereinafter, referred to as uncorrected video data) is supplied to the video correction circuit 5.

The acceleration sensor 7 detects acceleration in a certain direction as acceleration information. In the imaging device 1, the acceleration sensor 7 is attached to, for example, a housing or a chassis (not shown) to detect vertical acceleration applied to the entire imaging device 1 as acceleration information.

The integration circuit 8 integrates the acceleration information detected by the acceleration sensor 7 twice to generate motion amount information, and outputs the motion amount information to the offset cancel circuit 9.

The offset canceling circuit 9 removes components such as a steady error and a temperature drift generated by the acceleration sensor 7 and the integrating circuit 8 from the input motion amount information, and generates displacement amount information on the vertical displacement amount. I do.

The correction angle conversion circuit 10 converts the vertical displacement amount information from the offset cancel circuit 9 into angle information based on the focal length information to the subject supplied from the focus mechanism 2a of the optical system 2. The converted information is supplied to the correction amount conversion circuit 11 as correction angle information.

The correction amount conversion circuit 11 is based on the zoom magnification information supplied from the zoom mechanism 2 b of the optical system 2 and the correction angle information supplied from the correction angle conversion circuit 10, and outputs a signal from the camera signal processing circuit 4. The correction amount for the video data before correction is calculated and the calculation result is output to the video correction circuit 5 as correction amount information.

More specifically, the correction amount conversion circuit 11 calculates a deviation of the angle of view (image frame) due to vibration and shaking from the correction angle information, and corrects the calculation result based on the information of the zoom magnification. Thus, information about the position of the image cut out by the memory controller 13 of the video correction circuit 5 described later is generated, and the generated information is output to the video correction circuit 5 as correction amount information.

The image correction circuit 5 includes a camera signal processing circuit 4
Is subjected to a correction process based on the correction amount information from the correction amount conversion circuit 11, and the processed signal (hereinafter, referred to as corrected video data).
Is supplied to the encoder circuit 6.

The encoder circuit 6 performs processing such as D / A conversion and addition of a synchronization signal on the input corrected video data to generate an analog video video signal. Output to an external block such as a recording system.

Next, the correction processing performed by the video correction circuit 5 will be described with reference to FIGS. As shown in FIG. 2, for example, the image correction circuit 5 includes a memory 12 having a capacity capable of storing at least one frame of uncorrected image data, a camera signal processing circuit 4, an encoder circuit 6, a correction amount conversion circuit 11, and A memory controller 13 for controlling the memory 12;

The memory controller 13 of the video correction circuit 5
Temporarily writes the uncorrected video data from the camera signal processing circuit 4 into the memory 12 as video data of one frame. Then, the memory controller 13 converts the one frame of video data written in the memory 12 into
An image is cut out based on the correction amount information from the correction amount conversion circuit 11.

The state of this processing is schematically shown in FIGS. The memory controller 13 cuts out the video data 20 of one frame shown in FIG. 3A written in the memory 12 based on the correction amount information from the correction amount conversion circuit 11 as shown in FIG. The clipping position of the target clipped image 21 is specified.

FIG. 4 shows the relationship between the correction angle and the zoom magnification. FIG. 4A shows a case where the correction angle is zero, and FIGS. Each shows a case where the zoom magnification is different. That is, the memory controller 13 of the video correction circuit 5, when the correction angle of the video data 20 of one frame written in the memory 12 is zero, as shown in FIG. An image in a predetermined range is cut out as a cut-out image 21. Also, as shown in FIGS. 4B and 4C, when the correction angles of the video data 20 of one frame written in the memory 12 are equal, the memory controller 13 corrects the correction amount according to the zoom magnification. Cuts out an image in a predetermined range of the video data 20 as a cut-out image 21. Specifically, FIG. 4C shows a case where the cutout image 21 shown in FIG. 4C has a higher zoom magnification than the cutout image 21 shown in FIG. 4B. For example, if the zoom magnification is doubled, The correction amount is also doubled at the same ratio.

Further, the memory controller 13 is configured as shown in FIG.
As shown in (C), the cut-out image 21 is stored in the memory 1
2, and outputs the cut-out image 21 to the encoder circuit 6 as corrected video data.

By repeatedly performing such processing, the imaging apparatus 1 is mounted on a vehicle such as an automobile or a train as a vehicle-mounted camera. Thus, it is possible to output a shake-free image from the encoder circuit 6 and display it on a monitor or the like. Here, a case where the imaging device 1 is used as a vehicle-mounted camera of an automobile will be described with reference to FIG.

As shown in FIG. 5A, for example, an automobile 3
In the case where the imaging device 1 is mounted in the vehicle 0 and another imaging vehicle 31 running ahead is photographed by the imaging device 1 at a predetermined zoom magnification, the vehicle body of the automobile 30 is subject to irregularities on the road surface or acceleration or deceleration. Is vibrated up and down, the acceleration sensor 7 incorporated in the imaging device 1 detects this vibration as acceleration information. At this time, in the imaging device 1, the acceleration information from the acceleration sensor 7 is converted into displacement amount information via the integration circuit 8 and the offset cancellation circuit 9, so that the amount of vibration and shaking of the body of the automobile 30 can be reduced. , Displacement amount X.

When the vehicle 31 running ahead is the subject, the inter-vehicle distance between the vehicle 30 and the vehicle 31 is substantially equal to the focal length L, so that the correction is made as is clear from FIG. The angle θ ₁ can be represented by a calculation formula of θ ₁ = tan ⁻¹ (X / L). Therefore, in the imaging device 1, the correction angle conversion circuit 10 uses the information on the focal length L to the subject supplied from the focus mechanism 2a of the optical system 2 to calculate the vertical displacement X from the offset cancellation circuit 9. Is converted into information on the correction angle θ ₁ , and the converted information is supplied as correction angle information to the correction amount conversion circuit 11. Further, based on the correction amount information from the correction amount conversion circuit 11, By correcting the angle of view so that the image angle shift is canceled by the image correction circuit 5, the captured image is free from shaking and vibration.

Actually, in many cases, the vibration and shaking of the vehicle body of the automobile 30 are different between the front wheel side and the rear wheel side. In order to cope with such a case, two acceleration sensors 7 are connected to the integrating circuit 8, and these acceleration sensors 7 are connected to the front wheel side and the rear wheel side of the automobile 30 as shown in FIG. One may be attached to both sides.

Then, the displacement amount on the front wheel side is X₁And the rear wheel
X_TwoThe imaging device (in this case, acceleration
Since the sensor 7 is separated, the imaging device 1A is used. ) Before
It should be installed in the center between the wheels of the wheel and the rear wheel. this
In this case, as is clear from FIG.
L, distance l between wheels, correction angle θ_ThreeFor θ_Three= Θ₁+ Θ_Two  = Tan^-1((X₁+ X_Two) / L) + tan^-1((X₁−
X_Two) / L). Therefore, the imaging device 1A
In this case, the correction angle conversion circuit 10
Focal length L to the subject supplied from focus mechanism 2a
From the offset cancel circuit 9 based on the information
Vertical displacement X on both wheel sides₁, X_TwoInformation
Positive angle θ_ThreeAnd convert the converted information to the correction angle.
The correction amount is supplied to the correction amount conversion circuit 11 as information, and is further corrected.
Vibration / sway based on the correction amount information from the conversion circuit 11
The image correction circuit 5 cancels the angle of view deviation due to
By correcting the angle of view to
The accuracy of the angle correction has been improved,
There is no vibration.

As described above, according to the imaging devices 1 and 1A,
When mounted on a vehicle as an in-vehicle camera,
It is possible to photograph stably without being affected by vibration or shaking during traveling caused by acceleration or deceleration.

Further, according to the imaging devices 1 and 1A, the detection accuracy in the image processing system can be improved by correcting the image vibration and shaking in the image processing system that performs image processing such as tracking. Becomes possible.

In the above-described embodiment, the case where the image pickup apparatus is used as an on-vehicle camera of an automobile has been described. However, the present invention is not limited to this, and it is not limited to this. Of course, it can be used as an in-vehicle camera of any vehicle.

[0034]

As described above in detail, according to the imaging apparatus of the present invention, the video output correcting means detects the vertical vibration of the vehicle with respect to the video signal generated by the imaging means. Based on the detection result and the calculation result of the distance calculation means, the correction processing for the output video is performed, so that when used as an in-vehicle camera, it is possible to appropriately correct the vibration of the vehicle.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an imaging device to which the present invention has been applied.

FIG. 2 is a block diagram illustrating a configuration example of a video correction circuit of the imaging device.

3A and 3B are diagrams illustrating a process of clipping an image. FIG. 3A illustrates a state in which a center position of a clipped image to be clipped is specified for one frame of video data written in a memory. The state where the range of the cut-out image is calculated is shown in (C) of the cut-out image.

4A and 4B are diagrams for explaining a relationship between a correction angle and a zoom magnification, wherein FIG. 4A shows a cut-out image when the correction angle is zero, and FIGS. Each of the cut-out images when the magnification is different is shown.

5A and 5B are diagrams illustrating a case where the imaging apparatus is mounted in an automobile and used as an in-vehicle camera. FIG. 5A illustrates a case where another automobile is photographed, and FIG. 5B illustrates a correction angle θ.
_The principle of calculating ₁ will be described below.

6A and 6B are diagrams illustrating a case where an imaging apparatus according to another embodiment of the present invention is mounted in an automobile and used as an on-vehicle camera. FIG. 6A illustrates acceleration sensors on a front wheel side and a rear wheel side, respectively. for the case where the attached, respectively the principle of calculating the correction angle theta ₃ is (B).

[Explanation of symbols]

1, 1A imaging device, 2 optical system, 3 CCD imager, 4 camera signal processing circuit, 5 video correction circuit, 7
Acceleration sensor, 8 integration circuit, 10 correction angle conversion circuit, 11 correction amount conversion circuit, 12 memory, 13 memory controller, 21 cutout image, 30 automobile

Claims (6)

[Claims] 1. An image pickup apparatus mounted in a vehicle for picking up an image of an object outside the vehicle, comprising: an image pickup means for picking up an image of the object to generate an image pickup signal; and a vibration detection means for detecting a vertical vibration of the vehicle. A distance calculating means for calculating a distance to a subject; and a correction process for a video to be output based on the detection result of the vibration detecting means and the calculation result of the distance calculating means, for the video signal generated by the imaging means. An image pickup apparatus comprising: 2. The vehicle according to claim 1, wherein said vibration detecting means includes an acceleration sensor for detecting a vertical vibration of said vehicle by acceleration, and a displacement calculating means for calculating a vertical displacement of said vehicle from the acceleration detected by said acceleration sensor. The imaging device according to claim 1, comprising: 3. The image output correction unit temporarily stores the image signal generated by the imaging unit, and outputs an image of an image to be output based on a detection result of the vibration detection unit and a calculation result of the distance calculation unit. 3. The imaging device according to claim 2, wherein a correction process for the corner is performed. 4. The video output correction means calculates a vertical displacement of the vehicle detected by the vibration detection means in the vertical direction of the vehicle with respect to the angle of view of the video to be output, and the distance calculation means calculates the displacement. 4. The image pickup apparatus according to claim 3, wherein the distance to the subject is L, and the angle of view of the output video is corrected at a correction angle of θ = tan ^-1 (X / L). 5. The vibration detecting means is provided on a front wheel side of the vehicle, and detects first vertical vibration on a front wheel side of the vehicle, and is provided on a rear wheel side of the vehicle. A second vibration detecting means for detecting a vertical vibration on the rear wheel side of the vehicle, wherein the video output correcting means determines a detection result of each vibration detecting means for the video signal generated by the imaging means, and 2. The imaging apparatus according to claim 1, wherein a correction process is performed on a video to be output based on a calculation result of the distance calculation unit. 6. The image pickup apparatus according to claim 5, wherein the image pickup means is disposed at a substantially intermediate position between a front wheel side and a rear wheel side of the vehicle.