JPH08294056A - Video camera and drive method for solid-state image pickup element used for it - Google Patents

Abstract

PURPOSE: To realize remarkable cost reduction and low power consumption and to provide the video camera contributing to a miniaturized set by allowing hand-shake to be corrected with simple configuration of timing control only. CONSTITUTION: A CCD image sensor 11 having a light receiving area larger than that of an image pickup area providing an output of a video signal is used and a longitudinal motion sensor 19 and a lateral motion sensor 20 sense a motion in vertical and horizontal directions of the CCD image sensor 11 with respect to an object. Then, a CCD drive control circuit 13 controls a position of an image pickup area in the light receiving face of the CCD image sensor 11 in the vertical and horizontal directions on the basis of the sensing output and drives a vertical transfer section at a constant speed for a vertical valid period and drives it at a high speed for a vertical blanking period, and a horizontal transfer section at a constant speed for a horizontal valid period and drives it at a high speed for a horizontal blanking period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera,
In particular, the present invention relates to a video camera having a camera shake correction function and a method for driving a solid-state image sensor used in the video camera.

[0002]

2. Description of the Related Art A conventional example of this type of video camera is shown in FIG. In FIG. 9, the CCD image sensor 91 has a light receiving surface having a larger area than the image pickup area for outputting a video signal, and light from a subject enters the light receiving surface through the lens 92. A vertical transfer unit (not shown) of the CCD image sensor 91 is driven by a CCD drive control circuit 93 via a V (vertical) driver 94, and a horizontal transfer unit (not shown) is built in the CCD drive control circuit 93. It is driven by an H (horizontal) driver 93a. The CCD output of the CCD image sensor 91 is a sample hold (S /
H) After being sample-held by the circuit 95, Y (luminance)
Signal processing circuit 96 and C (chroma) signal processing circuit 97
Is signal-processed and is derived as a Y signal and a C signal.

The Y signal and the C signal are temporarily stored in the field memory 98 and then output as a Y / C composite video signal via the encoder 99. On the other hand, in the vicinity of the lens 92, a vertical movement detection sensor 100 that detects a vertical (vertical) component of vibration (hereinafter, referred to as hand shake) caused by a hand holding the camera body, and a horizontal (horizontal) direction.
A lateral movement detection sensor 101 for detecting the component of is attached. The respective detection outputs of the vertical movement detection sensor 100 and the horizontal movement detection sensor 101 are supplied to the movement amount calculation circuit 102, and the movement amount (camera shake amount) in each direction is calculated. This motion amount information is given to the memory control circuit 103 which controls the field memory 98.

[0004]

In the prior art having the above-mentioned structure, the CCD pixel information is temporarily stored in the field memory 98, and the vertical and horizontal directions corresponding to the respective detection outputs of the vertical motion detection sensor 100 and the lateral motion detection sensor 101 are stored. The shake correction is performed by controlling the vertical and horizontal read positions from the field memory 98 based on each shake amount in each direction. However, in order to perform camera shake correction, the field memory 98
In addition to the above, the memory control circuit 103 for controlling it is required, which results in high cost and large power consumption, and downsizing of the video camera.
It was an obstacle to weight reduction and price reduction.

Further, as another conventional example, as shown in FIG. 10, as a memory for temporarily storing CCD pixel information,
Line memory 104 capable of storing pixel information for one line
The pixel information read control from the line memory 104 is performed according to the amount of camera shake in the horizontal direction.
A charge sweep-out drain (not shown) is provided beside the horizontal transfer section of the D image sensor 91, and after transferring the charges of pixels outside the image pickup area determined based on the shake amount information in the vertical direction to the horizontal transfer section. It is also known that the CCD drive control circuit 93 performs the control for sweeping to the charge sweeping drain to perform the camera shake correction.

In this conventional example, since the CCD pixel information is temporarily stored in the memory only for the horizontal motion correction, the line memory 104 for one line is sufficient as the memory, which is costly. Although it is more advantageous in terms of power consumption than the case of the conventional example, CCD
Since it is necessary to provide a drain for discharging charges on the side of the horizontal transfer portion of the image sensor 91, it is not possible to use an existing product as the CCD image sensor 91 as it is.
Moreover, there is a problem that it hinders the miniaturization of the CCD image sensor itself.

The present invention has been made in view of the above problems, and an object of the present invention is to enable camera shake correction with a simple configuration of only timing control.
An object of the present invention is to provide a video camera that can significantly reduce the cost and reduce the power consumption and contribute to the downsizing of the set.

[0008]

A video camera according to the present invention includes a solid-state image sensor having a light-receiving surface having a larger area than an image-capturing area for outputting a video signal, and vertical and horizontal movements of the solid-state image sensor with respect to a subject. And a position control means for controlling the vertical and horizontal positions of the imaging area in the light-receiving surface of the solid-state image sensor based on the detection output of the motion detection means, and the vertical transfer of the solid-state image sensor. Drive unit that drives the unit at a constant speed during the vertical effective period and at a high speed during the vertical blanking period, and the horizontal transfer unit of the solid-state image sensor is driven at a constant speed during the horizontal effective period and at a high speed during the horizontal blanking period. And a horizontal drive control means.

[0009]

In the video camera having the above structure, the motion detecting means detects the vertical and horizontal movements of the solid-state image pickup device with respect to the object, and supplies the detection output (motion information) to the position control means. The position control means determines the vertical and horizontal positions of the image pickup area in the light receiving surface of the solid-state image pickup element, that is, the read-out position of the pixel information output as a video signal, based on this motion information. Then, in the vertical transfer of the read pixel information, the vertical drive control unit drives the vertical transfer unit of the solid-state image sensor at a constant speed during the vertical effective period and at a high speed during the vertical blanking period. In the horizontal transfer, the horizontal drive control unit drives the horizontal transfer unit of the solid-state image sensor at a constant speed during the horizontal effective period and at a high speed during the horizontal blanking period.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention. In FIG. 1, a CCD image sensor 1
Light from the subject enters the light-receiving surface 1 through the lens 12. As shown in FIG. 2, the CCD image sensor 11 includes a large number of photosensors (pixels) 1 which are two-dimensionally arranged in a horizontal direction (horizontal direction in the figure) and a vertical direction (vertical direction in the figure).
11 and a plurality of vertical registers (vertical transfer units) 112 arranged in each vertical column of the photosensors 111 and vertically transferring the signal charges read from the photosensors 111.
And an image pickup section 113 having a horizontal register (horizontal transfer section) 114 for horizontally transferring the signal charge sent from the vertical register 112, and the signal charge is detected in the subsequent stage of the horizontal register 114 and converted into a signal voltage. And a charge-voltage converter 115 that operates.

In this CCD image sensor 11,
The imaging unit 113 is an imaging area 1 that actually outputs a video signal.
It has a light receiving surface having an area larger than 16, that is, a light receiving surface having a larger number of pixels than the number of pixels displayed on the monitor. The vertical register 112 is basically driven in four phases by the vertical transfer clocks φV1 to φV4. Further, the horizontal register 115 has horizontal transfer clocks φH1 and φH2.
Is driven by two phases. This vertical transfer clock φV1
.About..phi.V4 is given from the V driver 14, and the horizontal transfer clocks .phi.H1 and .phi.H2 are given from the H driver 24 incorporated in the CCD drive control circuit 13. The V driver 14 and the H driver 24 are controlled in timing by the CCD drive control circuit 13.

The CCD output of the CCD image sensor 11 is sampled and held by the S / H circuit 15, and then subjected to signal processing by the Y signal processing circuit 16 and the C signal processing circuit 17 to be derived as a Y signal and a C signal. The Y signal and the C signal are sent to the NTSC / P in the encoder 18.
Formatted for the AL broadcasting standard and output as a Y / C composite video signal. On the other hand, in the vicinity of the lens 12, a vertical motion detection sensor 19 and a lateral motion detection sensor 20
Is attached. The vertical motion detection sensor 19 and the lateral motion detection sensor 20 separate the camera shake motion into “vertical shake” and “horizontal shake” depending on the mounting angles thereof, and the vertical (vertical) and horizontal (horizontal) directions of camera shake are detected. Detect each component.

The respective detection outputs of the vertical movement detection sensor 19 and the horizontal movement detection sensor 20 are supplied to a movement amount calculation circuit 21 constituted by a microcomputer, and the movement amount (camera shake amount) in each direction is calculated. This motion amount information is
It is given to the CCD drive control circuit 13. The CCD drive control circuit 13 performs a vertical camera shake correction drive circuit 22 for correcting a camera shake in the vertical direction based on the motion amount information in the vertical direction, and a camera shake correction in the horizontal direction based on the motion amount information in the horizontal direction. And a horizontal camera shake correction drive circuit 23 for

The concept of camera shake correction will now be described with reference to FIG.
It will be described based on. When the video camera moves due to the vibration of a human hand even though the subject is still, the image projected on the CCD image sensor 11 has a dotted line state as shown in FIG. Moves to the state of the solid line. This is a camera shake. Therefore, the CCD image sensor 11 having a light receiving surface having a larger area than the image pickup area for outputting a video signal is used, and when a hand shake occurs, the motion amount calculation circuit 21 causes the vertical motion detection sensor 19 and the lateral motion detection sensor 20. The amount of movement (camera shake amount) is converted into the number of pixels by calculating the detection information from. Then, it is given to the CCD drive control circuit 13 as formatted image stabilization data.

The CCD drive control circuit 13 controls the vertical and horizontal positions of the image displayed on the monitor based on the camera shake correction data supplied from the motion amount calculation circuit 21, and the V driver 14 drives the CCD. As a result, the image displayed on the monitor becomes a still image despite the shaking motion. That is, in FIG. 3, (B) shows a state without camera shake, (C) shows a state after camera shake correction, and a scattered area P indicates an image area displayed on the monitor. In the lower left corner of the figure
With reference to, the image projected on the monitor has the same horizontal distance H and vertical distance Y from the origin O to a certain point Q in any of the states (B) and (C). Become.

Next, a specific operation of correcting the shake in the vertical direction will be described. First, the CCD image sensor 11
Of the vertical pixels, the number of vertical actually used pixels actually used as an image, that is, the number of horizontal scanning lines (H) is determined by the broadcasting standard, and is 48 in the case of the NTSC system.
5H, 575H in the case of the PAL system. To obtain an image in the NTSC broadcasting standard, a CCD image sensor whose vertical direction is 485H or more is used. As an example, PA
If an L type CCD image sensor is used, the number of vertically usable pixels is 625H, as shown in FIG.
From 625-485 = 140, 140H is the allowable range for camera shake correction in the vertical direction.

In this CCD image sensor 11,
The pixel information of the image pickup area (actual use area) 116 in the vertical direction is read at a constant speed during the vertical effective period, and the pixel information of the correction areas 117 and 118 above and below the image pickup area 116 is vertical blanking. It is read by high-speed reading during the period. Here, of the correction regions 117 and 118 above and below the imaging region 116, the horizontal register 114
The correction area 117 on the side is a frame shift area, and the correction area 118 on the opposite side is a high-speed sweep area. And
When a camera shake motion occurs, the vertical position of the imaging region 116 is controlled according to the amount of vertical motion (camera shake amount).

That is, in FIG. 2, the number of steps of the frame shift area 117 is changed according to the amount of camera shake. As a result, the vertical position of the image pickup area 116 in the light receiving surface of the image pickup section 113 is determined, and by reading the pixel information of the image pickup area 116 as video information, an image in which camera shake correction has been applied with respect to vertical camera shake can be obtained. . Since the total number of steps in the frame shift area 117 and the high-speed reading area 118 is constant, when the number of steps in the frame shift area 117 increases / decreases in accordance with the amount of camera shake, high-speed reading is performed by the increased / decreased number of steps. The number of steps in the area 118 will decrease / increase.

FIG. 4 shows a timing chart of the vertical transfer drive system. In the normal case without the image stabilization operation,
Vertical transfer clock (φV1 to φV) in the imaging region 116
4) The V-Clock frequency is the line shift frequency, which is the same as the horizontal sync frequency, so it is 15.7 in the NTSC standard.
It becomes 34 kHz. On the other hand, the frame shift area 1
The vertical transfer clock V-Clock at 17 is about 300 kHz.
It will be about the frequency. In general, in order to increase the amount of camera shake correction, the frequency of the vertical transfer clock V-Clock in the frame shift area 117 and the high speed sweep area 118 may be increased.

However, the vertical transfer clock V-Clock
If the frequency is increased, the signal charges cannot be transferred completely in the vertical register 112, and transfer residue occurs. In particular,
Since the vertical transfer clock V-Clock that operates at high speed in the frame shift area 117 is common in the vertical register 112, the signal charge in the image pickup area 116 that is actually used as an image is also transferred by transferring the charge in the frame shift area 117 at high speed. Similarly, it will be transferred at high speed. If the vertical transfer deterioration occurs in the image pickup area 116 actually displayed on the monitor, the image quality deteriorates. Therefore, the frequency of the vertical transfer clock V-Clock in the frame shift area 117 is set up to the frequency at which vertical transfer deterioration does not occur.

On the other hand, in the high-speed sweep-out area 118, since the signal charge in the image pickup area 116 is transferred after the transfer is completed, it is not necessary to reliably transfer the signal charge.
Further, since there is a constraint that the high-speed transfer operation in the frame shift area 117 and the high-speed sweep operation in the high-speed sweep area 118 of the previous field are completed within the vertical blanking period, the time required for the high-speed sweep operation is as short as possible. Is preferred. From this, in the present embodiment, the imaging region 116 and the frame shift region 117
In contrast to the vertical transfer in the four-phase drive, the vertical transfer in the high-speed sweep-out region 118 is performed in the two-phase drive.

By the way, as the vertical transfer clock V-Clock, four vertical transfer clocks φV1 to φV4 are used. In case of 4-phase drive, vertical transfer clock φV
The phase relationship of 1 to φV4 has a phase difference of 90 °, as shown in FIG. 5 (A). On the other hand, in the case of two-phase driving, the phase relationship between the vertical transfer clocks φV1 to φV4 has a phase difference of 90 ° between φV1 and φV2, as shown in FIG. 5B, with respect to φV1 and φV2. As a result, φV3 and φV4 are in opposite phases. Switching between 4-phase driving and 2-phase driving is performed by the V driver 1
4, the vertical camera shake correction drive circuit 22 performs timing control.

In the case of four-phase driving, since the amount of charges handled is large, the signal charges can be completely transferred. Therefore, the frequency of the vertical transfer clock V-Clock in the frame shift area 117 is set under the above-mentioned conditions. As a result, the signal charges can be reliably transferred without causing vertical transfer deterioration. On the other hand, in the case of two-phase driving, the time required for one transfer is short and half that in the case of four-phase driving is required, so the time required for the high-speed sweeping operation can be set short. As described above, by adopting the two-phase driving method for the vertical transfer in the high-speed sweep area 117, the time required for the transfer operation can be shortened, so that the high-speed transfer operation must be completed within the vertical blanking period. You can have a time margin with.

By the way, at the time of high-speed transfer in the frame shift area 117, the signal charges transferred at high speed are accumulated in the horizontal register 114, and this can be swept out of the horizontal register 114 immediately by the transfer of the normal horizontal register 114. If the signal charges remain in the register, the remaining signal charges are mixed with the signal charges transferred from the vertical register 112 to the horizontal register 114 at the stage of line shift. As a result, as shown in FIG. 6, an overflow signal is output to the CCD output even if the vertical effective period starts. Moreover, in view of the above-described principle, when the number of stages (the number of lines) of the frame shift region 117 is small, the overflow signal is small, and the overflow signal is less likely to appear on the screen. Easy to appear on the screen.

In view of this, in this embodiment, the horizontal transfer clocks (φH1, φH) for driving the horizontal register 114 are used.
2) When the H-Clock frequency is, for example, a CCD image sensor with 250,000 pixels, as shown in FIG. 7, the speed is tripled (8/3 fsc; fsc is a subcarrier frequency) during normal driving ( By increasing the transfer speed up to 8 fsc) driving, the signal charges accumulated in the horizontal register 114 at high speed transfer in the frame shift region 117 are swept out at high speed.

In the high-speed transfer of the horizontal register 114 performed within the vertical blanking period, an unused signal (area 117) that enters the horizontal register 114 accompanying the high-speed operation of the vertical transfer clocks φV1 to φV4 for frame shift / high-speed sweeping is performed. , 118 signals), so that horizontal transfer deterioration may occur. This is because the operation is within the vertical blanking period during which no image is displayed. Further, in general, this horizontal transfer clock (φH
1, φH2) H-Clock sweep drive is more effective when the speed is higher. Here, the triple speed is the horizontal transfer clock H-Cloc in the CCD image sensor of 250,000 pixels.
This is because the frequency of k is 8/3 fsc, so that it can be set only up to 3 times (the source oscillation frequency is 8 fsc).

By doing so, at the time of high-speed transfer in the frame shift area 117, the signal charges transferred at high speed from the vertical register 112 to the horizontal register 114 can be immediately swept out from the horizontal register 114, and the sweep out can be performed vertically. Since it can be completed within the blanking period, the overflow signal is not output after entering the vertical valid period. Therefore, the image quality does not deteriorate due to the overflow signal.

The timing at which the driving frequency of the horizontal register 114 is raised is set to the vertical register 11 by the horizontal register 114.
When the signal charges are sequentially transferred from 2, that is, the high-speed transfer period in the frame shift region 117 and the high-speed sweep period in the high-speed sweep region 118. During these periods, since the vertical transfer rate rapidly increases, the transfer of the horizontal register 114 cannot catch up with the normal transfer rate of the horizontal register 114. Particularly, in the frame shift area 117, the number of frame shift steps changes according to the amount of camera shake correction, so the triple speed driving period of the horizontal register 114 is set to the same period as the maximum driving step number period of the frame shift area 117.

Next, a specific operation of the horizontal shake correction will be described. This horizontal camera shake correction drive control is realized by setting the horizontal transfer clock (φH1, φH2) H-Clock given to the horizontal register 114 to a high frequency within the horizontal blanking period and operating the horizontal register 114 at high speed. . However, since the high-speed driving of the horizontal register 114 is used as a countermeasure for suppressing the overflow signal described above, the high-speed driving for camera shake correction here is limited to the horizontal blanking period within the vertical effective period. Regarding the horizontal operating frequency, the position of the horizontal image output during the triple speed period shown in the timing of FIG. 8 is controlled during the control of the horizontal camera shake correction. That is, by changing the number of times the horizontal transfer clock H-Clock is driven in this portion in accordance with the amount of horizontal camera shake, a camera shake-corrected image in the horizontal direction is displayed on the monitor.

As described above, camera shake correction in both the vertical and horizontal directions can be realized. It should be noted that vertical motion correction is performed in field units at a minimum, and horizontal motion correction is performed in 1H units at a minimum.

As described above, when the CCD image sensor 11 having the light receiving surface having a larger area than the image pickup area 116 for outputting the video signal is driven, the vertical motion detecting sensor 19 is used.
The position of the imaging region 116 in the vertical / horizontal direction is controlled based on the detection outputs of the horizontal movement detection sensor 20, and the vertical drive is performed at a constant speed during the vertical effective period and at a high speed during the vertical blanking period. With respect to driving, by performing constant speed driving in the horizontal effective period and high speed driving in the horizontal blanking period, camera shake correction can be performed only by controlling the driving timing.

Therefore, it is not necessary to use a dedicated memory or to form a charge sweep-out drain in the CCD image sensor itself in order to perform camera shake correction. Since the existing PAL CCD image sensor can be used as it is, image stabilization can be realized at low cost and low power consumption. As a result, it is possible to contribute to the miniaturization of the set, and it is possible to promote the realization of the image stabilization function in the low-priced model.

[0033]

As described above, according to the present invention,
In image stabilization, the vertical / horizontal transfer unit is operated at high speed during the vertical / horizontal blanking period to control the vertical / horizontal position in the light-receiving surface of the image pickup area for outputting a video signal. Since the camera shake correction can be realized only by controlling the drive timing, it is possible to significantly reduce the cost and reduce the power consumption and contribute to the downsizing of the set.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a CCD image sensor.

FIG. 3 is a conceptual diagram of camera shake correction.

FIG. 4 is a timing chart for explaining the operation of the vertical transfer drive system.

FIG. 5 is a timing chart of a vertical transfer clock.

FIG. 6 is a timing chart for explaining an operation when an overflow signal is output.

FIG. 7 is a timing chart for explaining an operation when an overflow signal is suppressed.

FIG. 8 is a timing chart for explaining the operation of the horizontal transfer drive system.

FIG. 9 is a configuration diagram showing a conventional example.

FIG. 10 is a configuration diagram showing another conventional example.

[Explanation of symbols]

 11 CCD image sensor 13 CCD drive control circuit 15 Sample hold circuit 19 Vertical motion detection sensor 20 Horizontal motion detection sensor 21 Motion amount calculation circuit 22 Vertical camera shake correction drive circuit 23 Horizontal camera shake correction drive circuit 111 Photo sensor (pixel) 112 Vertical register 113 Imaging unit 114 Horizontal register 116 Imaging area 117 Frame shift area 118 High-speed sweeping area

Claims (4)

[Claims] 1. A solid-state imaging device having a light-receiving surface having an area larger than an imaging region for outputting a video signal, motion detecting means for detecting vertical and horizontal movements of the solid-state imaging device with respect to a subject, and the motion. Position control means for controlling the vertical and horizontal positions of the imaging area in the light receiving surface of the solid-state image sensor based on the detection output of the detection means; A vertical drive control unit that drives and drives at a high speed during a vertical blanking period, and a horizontal drive control unit that drives the horizontal transfer unit of the solid-state image sensor at a constant speed during a horizontal effective period and at a high speed during a horizontal blanking period. A video camera characterized by: 2. The vertical drive control means carries out vertical transfer in an area on the horizontal transfer section side in the vertical direction outside the imaging area on the light receiving surface of the solid-state imaging device by four-phase driving, 2. The video camera according to claim 1, wherein vertical transfer in a region on the opposite side is performed by two-phase driving. 3. The video camera according to claim 1, wherein the horizontal drive control means drives the horizontal transfer unit at a high speed during a horizontal blanking period within a vertical effective period. 4. A method of driving a solid-state image sensor having a light-receiving surface having an area larger than that of an image-capturing area for outputting a video signal, wherein vertical and horizontal movements of the solid-state image sensor with respect to a subject are detected. The vertical and horizontal positions of the imaging area in the light receiving surface of the solid-state image sensor are controlled based on the detected amount of movement, and during vertical transfer, the vertical transfer section of the solid-state image sensor is fixed during the vertical effective period. It is characterized in that it is driven at a high speed and is driven at a high speed in the vertical blanking period, and at the time of horizontal transfer, the horizontal transfer unit of the solid-state image pickup device is driven at a constant speed in the horizontal effective period and at a high speed in the horizontal blanking period. Driving method of solid-state imaging device.