JP2010252027A - Video camera with turntable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video camera with a turntable for suppressing the occurrence of video distortion during imaging. <P>SOLUTION: A control part 21 receives a shutter time 202 of a CMOS image sensor 23, calculates the maximum rotation speed that does not cause video distortion on the basis of the received shutter time 202, and controls the rotation speed of a turntable 30 within the maximum rotation speed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a video camera with a turntable that outputs a video signal without distortion by controlling, for example, a video camera using a complementary metal oxide semiconductor (CMOS) image sensor as an image sensor and a turntable for rotating the video camera. It is.

  In general, a video camera using a CMOS image sensor reduces brightness by reducing the amount of light received by increasing the shutter speed for a bright subject with high illuminance, and lowering the shutter speed for a subject with low illuminance. By increasing the amount of received light, the brightness is increased, and the operation is always performed to output a video with high visibility.

  However, the amount of distortion of the moving imaging object changes depending on the shutter speed of the CMOS image sensor. Since a CMOS image sensor generally employs line exposure (rolling shutter), the lower the shutter speed, the greater the shift in the time axis direction and the greater the distortion of the output image.

  In Patent Document 1, in a video camera using a CMOS image sensor as an image pickup device, when shooting is performed by moving the image pickup direction up and down, left and right, such as pan and tilt, the magnification in the moving direction of the image (for example, moving in the horizontal direction). For a subject, a technique for correcting image distortion by changing the magnification of the image in the horizontal direction of the image sensor is disclosed.

Japanese Patent Laying-Open No. 2007-20045 (page 1-9, FIG. 1)

  However, since the conventional techniques including Patent Document 1 correct the video by changing the image cut-out magnification with respect to the horizontal video distortion that has occurred at the time of imaging, There has been a problem that an image distortion amount and an afterimage increase in proportion to the moving speed and the exposure time. For example, when the subject moves in the horizontal direction, the subject is distorted obliquely, and a phenomenon in which an afterimage proportional to the exposure time increases behind the moving direction has occurred.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a video camera with a turntable that suppresses the occurrence of image distortion and afterimages.

  The video camera with a turntable according to the present invention is a video camera with a turntable provided with a turntable for rotatably supporting the video camera. The video camera has a shutter time at the time of capturing an image according to the illuminance of the image target. An image pickup unit that controls brightness by changing and outputs a shutter time at the time of video capture, and inputs a rotation direction and a rotation speed from the outside to instruct the turntable, and according to the shutter time acquired from the image pickup unit And a control unit for controlling the rotation speed of the turntable.

  According to the video camera with a turntable according to the present invention, the control unit acquires the shutter time of the imaging unit, and controls the rotation speed of the turntable based on the correlation between the acquired shutter time and the rotation speed of the turntable. With this configuration, the turntable can be rotated at a rotation speed that does not cause image distortion or afterimage. As a result, an image with high visibility can be output.

It is a block diagram which shows the structure of the video camera with a turntable which concerns on Embodiment 1 of this invention. 3 is a flowchart illustrating control of the video camera with a turntable according to the first embodiment. It is a block diagram which shows the structure of the video camera with a turntable which concerns on Embodiment 2 of this invention. 10 is a flowchart illustrating control of the video camera with a turntable according to the second embodiment. It is a block diagram which shows the structure of the video camera with a turntable which concerns on Embodiment 3 of this invention. 10 is a flowchart illustrating control of the video camera with a turntable according to the third embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating a functional configuration of a video camera with a turntable according to the first embodiment.
As shown in FIG. 1, the video camera with a turntable includes a video camera 20 and a turntable 30, and the video camera 20 is rotatably supported by the turntable 30. The video camera 20 includes a control unit 21, a CMOS image sensor (imaging unit) 23, a signal processing unit 25, a lens (not shown), and the like.

  The control unit 21 is, for example, a CPU, and based on an instruction signal 200 including an imaging start instruction input from an operator via an operation unit (not shown), a rotation direction and a rotation speed of the turntable 30, and the CMOS image sensor 23 The turntable 30 is controlled. For example, the control unit 21 outputs the imaging instruction signal 200a to the CMOS image sensor 23 to cause the CMOS image sensor 23 to start imaging, outputs the rotation instruction signal 200b to the turntable 30, and instructs the rotation direction and the rotation speed. Yes. Further, the control unit 21 acquires a shutter time (shutter speed) 202 from the CMOS image sensor 23, and outputs a rotation speed control signal 203 to the turntable 30 according to the acquired shutter time 202 to rotate the turntable 30. The speed is controlled.

The CMOS image sensor 23 is an image sensor, accumulates light from a lens (not shown) for a predetermined time based on an image capturing instruction signal 200 a from the control unit 21, converts the light into an electric signal, and outputs it as an image signal 101. In addition, the CMOS image sensor 23 controls the luminance by changing the gain of the internal video amplifier and the shutter time (shutter speed) at the time of capturing the video in accordance with the illuminance of the imaging target. The image pickup signal 101 is configured to be output, and the shutter time 202 at the time of capturing an image is output to the control unit 21.
Note that the brightness control may be performed by the video camera 20 configured to be realized by an external circuit of the CMOS image sensor 23.

  The signal processing unit 25 performs arithmetic processing on the imaging signal 101 received from the CMOS image sensor 23 and outputs a video signal 102 in a video output format.

  The turntable 30 is rotatably supported, for example, by placing the video camera 20 thereon, and includes a motor that rotates to change the shooting direction of the video camera 20.

Next, the correlation between the shutter time of the CMOS image sensor 23 and the rotation speed of the turntable 30 will be described.
In general, the longer the shutter time, the brighter the image that can be taken, and the low-illuminance subject is configured to ensure a highly visible image by reducing the shutter time. However, there is a problem that the longer the shutter time (the lower the shutter speed), the larger the image distortion and afterimage when a moving subject is imaged.

Therefore, when the rotation speed of the turntable 30 is controlled by the control unit 21, information on the shutter time acquired from the CMOS image sensor 23 is used. Specifically, if the shutter time of the CMOS image sensor 23 is short (when the shutter speed is high), an image with less image distortion and afterimage can be secured even if the rotation speed of the turntable 30 is increased. For example, the shutter time of the CMOS image sensor 23 is indicated as Ts, the maximum rotation speed of the turntable 30 is indicated as Vr_max, and the correlation as in the following equation is defined.

Vr_max = (K / Ts) (1)
K is a constant.

  As shown in the equation (1), when the maximum rotation speed Vr_max is inversely proportional to the shutter time Ts of the CMOS image sensor 23, the rotation speed of the turntable 30 is long when the shutter time Ts is long (the shutter speed Vs is low). By suppressing Vr, the distortion amount and afterimage of the video signal 102 can be reduced.

The control operation of the video camera with a turntable according to the first embodiment will be described below.
FIG. 2 is a flowchart for explaining control of the video camera with a turntable according to the first embodiment.

  As described above, the control unit 21 transmits the imaging instruction signal 200a to the CMOS image sensor 23 according to the instruction signal 200 from the operation unit, and transmits the rotation instruction signal 200b that instructs the rotation direction and the rotation speed to the turntable 30. (Step ST11).

  When the imaging starts in accordance with the imaging instruction signal 200a, the CMOS image sensor 23 transmits the imaging signal 101 to the signal processing unit 25 and transmits the shutter time 202 controlled according to the illuminance of the imaging target to the control unit 21. The control unit 21 receives the shutter time 202 from the CMOS image sensor 23 (step ST12).

  When the control unit 21 calculates the maximum rotation speed Vr_max based on the received shutter time 202 and the previously stored formula (1) (step ST13), the rotation limiting the rotation speed to be equal to or less than the maximum rotation speed Vr_max. The speed control signal 203 is transmitted to the turntable 30 (step ST14). The turntable 30 rotates with the rotation speed set to the maximum rotation speed Vr_max or less based on the rotation speed control signal 203.

  That is, even if the instruction from the operator is equal to or higher than the maximum rotation speed Vr_max, the rotation speed Vr is suppressed to Vr_max or less. When the illuminance of the imaging target changes and the maximum rotation speed Vr_max changes, if the turntable 30 rotates at a new maximum rotation speed Vr_max or higher, the rotation speed control signal 203 sets the rotation speed to the new maximum speed. The rotation speed is suppressed to Vr_max or less.

  When receiving a stop instruction from an operation unit (not shown), the control unit 21 stops the operation of the COMS image sensor 23 and the turntable 30 (step ST15).

  As described above, according to the first embodiment, the control unit 21 acquires the shutter time 202 from the CMOS image sensor 23 and outputs the rotation speed control signal 203 to the turntable 30 according to the acquired shutter time 202. Thus, by controlling the rotation speed of the turntable 30, it is possible to suppress the occurrence of image distortion and afterimage.

Embodiment 2. FIG.
In the first embodiment, the configuration in which the operator instructs the rotation direction and the rotation speed of the turntable 30 via the operation unit has been described. However, the second embodiment is a video camera with a turntable that is automatically operated. A form is demonstrated.

  FIG. 3 is a block diagram showing a functional configuration of the video camera with a turntable according to the second embodiment. 3 is provided with a recording device 28 for storing the video output from the video camera with a turntable in FIG. 1. The same components as those in FIG. 1 are denoted by the same reference numerals, and the same description is omitted. .

  When the video camera with a turntable of the present invention is operated as a surveillance camera for the purpose of crime prevention, for example, a control program for reciprocating between two predetermined points is stored in advance and is operated automatically. There are many cases. This is generally called an auto pan or auto tilt function.

  When using the auto pan or auto tilt function, the video signal captured by the CMOS image sensor 23 and processed by the signal processing unit 25 is stored in a recording device 28 as shown in FIG. However, since there is no operator in the automatic operation, it is impossible to check the state of image blurring due to image distortion or afterimage during operation.

  Therefore, by adopting the same configuration as in the first embodiment, the video signal 102 without video distortion and afterimage is transmitted to the recording device 28.

  The video camera with a turntable includes a video camera 20 and a turntable 30 as in the first embodiment, and the turntable 30 supports the video camera 20 so as to be rotatable. The video camera 20 includes a CMOS image sensor 23, a signal processing unit 25, a control unit 27, a recording device 28, a lens (not shown), and the like. The CMOS image sensor 23 and the signal processing unit 25 are the same as those in the first embodiment. It is the composition.

  The control unit 27 preliminarily receives an instruction signal 201 including an automatic photographing start instruction, an automatic rotation direction and automatic rotation speed of the turntable 30, and a recording start instruction of the recording device 28, which are input from the operator via an operation unit (not shown). Based on the stored program or the like, the CMOS image sensor 23, the turntable 30, and the recording device 28 are controlled to operate automatically.

  For example, when the control unit 27 receives the instruction signal 201 from the operation unit, the control unit 27 outputs an automatic imaging instruction signal 201a to the CMOS image sensor 23 to cause the CMOS image sensor 23 to start imaging, and sends an automatic rotation instruction signal 201b to the turntable 30. Is output, and the rotation direction and rotation speed that change repeatedly at predetermined intervals are indicated. The control unit 27 acquires the shutter time 202 from the CMOS image sensor 23 and outputs a rotation speed control signal 203 to the turntable 30 according to the acquired shutter time 202 to control the rotation speed of the turntable 30. . Further, the control unit 27 outputs a recording instruction signal 204 to the recording device 28 to cause the recording device 28 to start recording.

  When receiving the recording instruction signal 204 from the control unit 27, the recording device 28 stores the video signal 102 imaged by the CMOS image sensor 23 and processed by the signal processing unit 25.

The operation will be described.
FIG. 4 is a flowchart for explaining operation control of the video camera with a turntable according to the second embodiment.
The control unit 27 transmits an automatic imaging instruction signal 201a to the CMOS image sensor 23 in accordance with the instruction signal 201 from the operation unit, and transmits an automatic rotation instruction signal 201b for instructing the rotation direction and the rotation speed to the turntable 30 for recording. The recording instruction signal 204 is transmitted to the device 28 (step ST21).

  When imaging starts in accordance with the automatic imaging instruction signal 201a, the CMOS image sensor 23 transmits the imaging signal 101 to the signal processing unit 25 and transmits the shutter time 202 controlled according to the illuminance of the imaging target to the control unit 27. . The control unit 27 receives the shutter time 202 from the CMOS image sensor 23 (step ST12).

  As in the first embodiment, the control unit 27 calculates the maximum rotation speed Vr_max based on the received shutter time 202 and the previously stored formula (1) (step ST13), and the rotation speed becomes the maximum rotation speed Vr_max. A rotation speed control signal 203 that is limited to the following is transmitted to the turntable 30 (step ST14). The turntable 30 rotates with the rotation speed set to the maximum rotation speed Vr_max or less based on the rotation speed control signal 203.

  That is, when the illuminance of the imaging target changes due to automatic imaging and automatic rotation and the maximum rotation speed Vr_max changes, the rotation speed control signal 203 is determined when the turntable 30 rotates at a new maximum rotation speed Vr_max or more. Thus, the rotation speed is suppressed to a new maximum rotation speed Vr_max or less.

The signal processing unit 25 receives the imaging signal 101 output from the CMOS image sensor 23, performs arithmetic processing on the imaging signal 101, and outputs it as a video signal 102.
The recording device 28 starts recording according to the recording instruction signal 204 from the control unit 27 and receives and stores the video signal 102 from the signal processing unit 25.

When there is a stop instruction from the operation unit (step ST25 “YES”), the control unit 29 stops the imaging operation of the CMOS image sensor 23 and stops the rotation operation of the turntable 30. Further, the recording of the recording device 28 is also stopped (step ST26).
When there is no imaging stop instruction from the operation unit ("NO" in step ST25), the operations from step ST12 to step ST14 are repeated.

  As described above, according to the second embodiment, the control unit 27 acquires the shutter time 202 from the CMOS image sensor 23 and outputs the rotation speed control signal 203 to the turntable 30 according to the acquired shutter time 202. Thus, by controlling the rotation speed of the turntable 30, it is possible to suppress the occurrence of image distortion and afterimage. As a result, the recording device 28 can store the video signal 102 in which no video distortion or afterimage occurs.

Embodiment 3 FIG.
In the first embodiment, the configuration in which the rotation speed of the turntable 30 is controlled according to the shutter time of the CMOS image sensor 23 has been described. However, in the third embodiment, the rotation speed of the turntable 30 is preferentially secured. A configuration for suppressing image distortion and afterimage will be described.

  FIG. 5 is a block diagram showing a functional configuration of a video camera with a turntable according to the third embodiment. FIG. 5 is a diagram in which communication between the CMOS image sensor 23 and the control unit 29 is performed bidirectionally. The same components as those in the video camera with a turntable in FIG. Will not be described.

  Similarly to the first embodiment, when receiving an instruction signal 200 from an operation unit (not shown), the control unit 29 outputs an imaging instruction signal 200a to the CMOS image sensor 23, and includes a rotation direction and a rotation speed to the turntable 30. A rotation instruction signal 200b is output. The control unit 29 acquires a shutter time (shutter speed) 202 from the CMOS image sensor 23, and outputs a rotation speed control signal 203 to the turntable 30 in accordance with the acquired shutter time 202, thereby setting the rotation speed of the turntable 30. I have control.

In addition, when the priority instruction signal 205 that receives priority by fixing the rotation speed of the turntable 30 from an operation unit (not shown) is received, the rotation speed of the turntable 30 is fixed and the longest shutter time is determined. For example, the rotation speed of the turntable 30 instructed by the priority instruction signal 205 is represented by Vr ′, the longest shutter time is represented by Ts_max, and is calculated by the following equation (2).

Ts_max = (K / Vr ′) (2)
K is a constant.

Based on the calculated longest shutter time Ts_max, the control unit 29 transmits a shutter time limit signal 206 so as to limit the shutter time of the CMOS image sensor 23 within the longest shutter time Ts_max.

Next, the operation will be described.
FIG. 6 is a flowchart for explaining the operation of the video camera with a turntable according to the third embodiment. In FIG. 6, steps ST11 to ST14 are the same as those in FIG.

  In step ST14, the control unit 29 controls the rotation speed of the turntable 30 to be equal to or less than the maximum rotation speed Vr_max. Next, step ST12 to step ST14 are repeated until the priority instruction signal 205 is received from the operation unit (step ST31 “NO”), and when the priority instruction signal 205 giving priority at the rotation speed Vr ′ is received (step ST31 “YES”), The rotational speed is fixed at Vr ′, the longest shutter time Ts_max corresponding to the rotational speed Vr ′ is calculated by the above equation (2) (step ST32), and the CMOS image sensor 23 is within the calculated longest shutter time Ts_max. A shutter time limit signal 206 for controlling the shutter time is transmitted (step ST33). When receiving the shutter time limit signal 206, the CMOS image sensor 23 takes an image with a shutter time within a time Ts_max.

  For example, when the rotation speed of the turntable 30 is high, the image is obtained by limiting the shutter time of the CMOS image sensor 23 within a certain short time (that is, limiting the shutter speed to a certain high speed or more). Shake can be minimized. On the contrary, when the rotation speed is slow, the shutter time of the CMOS image sensor 23 is allowed up to a long time (that is, the shutter speed is allowed to a certain low speed), thereby allowing image distortion and afterimages to be allowed. The brightness of the image can be secured above.

  As described above, according to the third embodiment, the control unit 29 outputs the shutter time limit signal 206 corresponding to the fixed rotation speed to the CMOS image sensor 23 to control the shutter speed of the CMOS image sensor 23. Thus, priority can be given to the rotation speed of the turntable 30, and the occurrence of image distortion and afterimage can be suppressed.

  In the present invention, the control unit 21 is configured to receive the shutter time 202 from the CMOS image sensor 23 and rotate the turntable 30 at a rotation speed corresponding to the shutter time 202, for example, when the shutter time is long. Since distortion of the output image becomes large, the rotation speed of the turntable 30 is slowed (below a certain level) to provide an image with high visibility. In addition, since the distortion is reduced when the shutter time is short, the operation comfort can be ensured by giving priority to the rotation speed of the turntable 30. As a result, it is possible to improve the visibility regardless of the illuminance by adopting the surveillance camera system particularly for the purpose of crime prevention, and the crime prevention purpose can be made more effective.

  20 video camera, 21, 27, 29 control unit, 23 CMOS image sensor (imaging unit), 25 signal processing unit, 28 recording device, 30 turntable, 101 imaging signal, 102 video signal, 200, 201 instruction signal, 200a imaging Instruction signal, 200b Rotation instruction signal, 201a Automatic imaging instruction signal, 201b Automatic rotation instruction signal, 202 Shutter time, 203 Rotational speed control signal, 204 Recording instruction signal, 205 Priority instruction signal, 206 Shutter time limit signal

Claims (3)

In a video camera with a turntable having a turntable that rotatably supports the video camera,
The above video camera
An imaging unit that controls the brightness by changing the shutter time at the time of video capture according to the illuminance of the video target, and outputs the shutter time at the time of video capture;
And a control unit that inputs the rotation direction and the rotation speed from outside and instructs the rotation table, and controls the rotation speed of the rotation table in accordance with the shutter time acquired from the imaging unit. A video camera with a turntable.   2. The video camera with a turntable according to claim 1, wherein the control unit inputs from the outside a rotation direction that repeatedly changes at a predetermined interval and instructs the turntable.   2. The video camera with a turntable according to claim 1, wherein the control unit controls a shutter time of the imaging unit in accordance with a rotational speed input from the outside.

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