JPH0316470A - Hand blur correction device - Google Patents

Abstract

PURPOSE:To decrease a change in the level of a picture at changeover of the correction state and normal state by selecting the reduction rate N to be the unity when the amplitude of a moving vector detected by a moving vector detection circuit is threshold level or below for a prescribed time and selecting the reduction rate N to be a prescribed reduction rate N0 when the level exceeds the threshold level. CONSTITUTION:When a moving vector signal is discriminated by a vector quantity detection circuit 10 and the vector quantity reaches a prescribed level or below, an arithmetic circuit 11 controls a memory readout control circuit 4 so that all signals in the memory (N=1) are outputted as they are. When it is recognized by the vector quantity detection circuit 10 that a moving vector of a prescribed amplitude exists for a prescribed time and the value N of the memory readout control circuit 4 is changed immediately from the memory 6 up to the set reduction rate N0 from the state of N=1 and hand blur is corrected and the pattern is magnified by a multiple of N and the output is given to an interpolation magnification circuit 6 to change over switches 12, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image stabilization device for an imaging device.

BACKGROUND OF THE INVENTION Conventional image stabilization devices are described in, for example, the Televisión Society Report, vol. 11 NO. 3. About the screen shake correction device.

FIG. 5 is an overall block diagram of this conventional image stabilization device, and 1 is an A/D converter for input NTSC video signals.
/D converter. 2 is a YC separation circuit that extracts only the Y signal of the A/D converted signal. 3 is 1 from Y signal
This is a motion vector detection circuit that detects how much vector movement has occurred compared to the previous frame. 4 is a memory read control circuit which obtains information on the amount of vector movement from the vector detection circuit and determines which position in the memory to output a picture, and 5 is a memory in which the delayed A/D conversion output of the NTSC signal is written. , 6 is an interpolation/enlargement circuit that interpolates and enlarges an image obtained by taking a part of the screen from the memory.When passing through this circuit 6, a video signal enlarged to a predetermined screen size is output. 7 is the output digital signal.
This is a D/A converter that converts into an SC signal.

In the conventional image stabilization device configured as described above, an NTSC video signal with screen shake is A/D converted by the A/D converter 1 and distributed to two systems. One of them is sent to the YC separation circuit 2, where only the Y signal is taken out and input to the motion vector detection circuit 4. The motion vector detection circuit 3 detects a motion vector using a representative point matching method that compares data at a representative point of a signal of the previous field with data of a representative point of a signal of the current field. The memory read control circuit 4 uses the motion vector detected by this circuit.
However, by changing the readout address of the video signal once written in the memory 5, the position of the image is moved.

In other words, as shown in FIG. 6, a certain frame Fl of the input image,
F2. ..., but the frame to be extracted is translated in parallel within the entire screen based on the motion vector A to remove screen shaking, and the position of this frame to be extracted is changed by changing the read address. operate by

The output image here is corrected for camera shake by extracting a fixed frame of the normal screen size, so the size of the image output from the memory is interpolated to the normal size, and the enlargement and interpolation operation is performed using the enlargement circuit 6. The signal is then output as an NTSC signal by performing D/A conversion using a 7-mod D/A conversion circuit.

Problems to be Solved by the Invention However, with the above configuration, even when no camera shake occurs, the resolution of the output screen is limited because it goes through a circuit that takes a certain frame of the photographed screen and interpolates and enlarges that screen. However, there are problems in that the noise is degraded and the noise is amplified.

Furthermore, since the image is enlarged in the image stabilization state, there is a drawback that when switching between the image stabilization state and the normal state, the size of the reproduced image changes, making it momentarily unsightly.

In view of this, the present invention improves image quality by performing camera shake correction when camera shake is occurring, and disables camera shake correction when there is no camera shake, and also when switching between the correction state and the normal state. Providing an image stabilization device with little change in image size The invention of claim 1 of the present application is an image stabilization device that corrects image shaking caused by camera shake, and includes a motion vector detection method that detects a motion vector of an image signal. a circuit, an image memory that holds the image signal for at least one field, and a readout address of the image memory that changes a read address of the image memory based on a motion vector of the motion vector detection circuit to 1/N of the entire screen (N is a reduction rate). a memory readout control circuit that extracts the signal of the motion vector, an interpolation and enlargement circuit that multiplies the 1/N portion of the image signal read from the image memory by N and converts it into a full-screen signal, and a motion vector detected by the motion vector detection circuit. The memory read control circuit and the interpolation enlargement circuit are configured such that the reduction rate N becomes 1 when the magnitude of the motion vector is below a predetermined threshold level for a predetermined time, and the reduction ratio N becomes a predetermined reduction ratio NQ when the magnitude exceeds the threshold level. The present invention is characterized in that it includes a control arithmetic circuit.

Further, the invention according to claim 2 of the present application is an image stabilization device for correcting image shake caused by camera shake, which comprises a zoom control means for changing an input image range of the camera, and an image obtained by the zoom control means. an image signal input means for converting into an image signal; a motion vector detection circuit for detecting a motion vector of the image signal; an image memory for retaining at least one field of the image signal; and a motion vector detection circuit based on the motion vector of the motion vector detection circuit. a memory readout control circuit that changes the readout address of the image memory to take out a signal of 1/N (N is a reduction ratio) of the entire screen; The reduction rate N becomes 1 when the magnitude of the motion vector detected by the interpolation enlargement circuit that converts it into a full-screen signal and the motion vector detection circuit is below a predetermined threshold level for a predetermined time, and when it exceeds the threshold level, the reduction ratio N becomes 1. N is the predetermined reduction rate N
8, and an arithmetic circuit that controls the memory readout control circuit and the interpolation enlargement circuit so that the size of the screen becomes 8, and controls the zoom ratio so that the size of the screen is not changed by the zoom control means when the screen is enlarged or reduced. It is characterized by this.

Furthermore, the invention according to claim 3 of the present application is characterized in that it further includes a switch means for switching between the presence and absence of camera shake correction.

According to the invention of claim 1 of the present application having such features, the motion vector of the image signal is detected by a motion vector detection circuit, and the read address of the memory holding the image signal is changed based on the motion vector. The 1/H signal of the entire screen is read out and expanded by interpolation to prevent camera shake.

In addition, in the invention of claim 2 of the present application, in addition to this, the input image range of the camera is changed by the zoom control means, and the zoom ratio is controlled so that the size of the screen does not change when the screen is enlarged or reduced. There is. Furthermore, in the invention of claim 3, the presence or absence of camera shake correction is switched by a switch.

Embodiment FIG. 1 shows a block diagram of an image stabilization device according to a first embodiment of the present invention. In FIG. 1, 1 to 7 are the same as those of the conventional camera shake correction device shown in FIG. 5, and have the same function, so a description thereof will be omitted. 1
0 is a vector quantity checking circuit that detects whether the motion vector is below a certain level or above a certain level, and the arithmetic circuit 11 receives information from the vector quantity checking circuit 10 and operates the memory read control circuit 4 and a switch. Circuit 12.
13. The switch circuits 12 and 13 are switches for switching whether or not to pass the signal read from the memory 5 through the interpolation/enlargement circuit 6.

The operation of the image stabilization device of this embodiment configured as described above will be described below. The Y signal separated by the YC separation circuit 2 enters a motion vector detection circuit 3 and a motion vector is detected. This motion vector signal is discriminated by the vector quantity verification circuit 10, and when the vector quantity becomes below a predetermined level, the arithmetic circuit 11 detects a screen area of 17N (
N is the reduction ratio), and the memory readout control circuit 4, which performs camera shake correction, is controlled so that N=1, that is, all the signals in the memory are output as they are. Further, the switch circuits 12 and 13 are controlled so as not to allow the interpolation and expansion circuit 6 to pass through. Next, in the case of image stabilization recovery, if the vector amount verification circuit 10 recognizes that the vector was O for a predetermined period and then a motion vector of a predetermined magnitude was present for a predetermined time, the value of N in the memory read control circuit 4 is determined. N=1
The state is immediately changed to the set reduction ratio N9 value, 1/N of the screen is read out from the memory 5, camera shake is corrected, and the output from the memory 5 is passed through the interpolation enlargement circuit 6 in order to multiply the screen by N. The switches 12 and 13 are controlled to switch.

As described above, according to this embodiment, if a motion vector is detected and there is no camera shake, the captured video is output as is, and if camera shake occurs, it is checked and camera shake correction is performed. can be improved. This embodiment can also be performed by microcomputer control.

FIG. 2 shows a block diagram of an image stabilization device according to a second embodiment of the present invention. In FIG. 2, 1 to 7 are the same as those of the conventional example and have the same function, so their explanation will be omitted. The vector quantity checking circuit 120 is used to check whether the motion vector is below a certain level or above a certain level, and the arithmetic circuit 21 is used to control the memory read control circuit 4 and the interpolation enlargement control circuit 6. .

The operation of the image stabilization device of the second embodiment configured as described above will be described below. As in the first embodiment, the Y signal separated by YC from the YC separation circuit 2 shown in FIG. 2 enters the motion vector detection circuit 3, where a motion vector is detected. In this case, when the vector amount checking circuit 20 detects that the motion vector is below a predetermined level, the memory readout control circuit 4, which performs camera shake correction by extracting 1/N of the screen area, and the memory The arithmetic circuit 21 calculates and controls the memory read control circuit 4 and the interpolation enlargement circuit 6 so that the two N values of the interpolation enlargement memory 6, which multiplies the output from the memory readout control circuit 4 by N, gradually approach 1. do. Next, in the case of restoring image stabilization, if the vector checking circuit 20 recognizes that the motion vector was 0 for a predetermined period of time and then a motion vector of a predetermined size was present for a predetermined period of time, a memorandum indicating that N=1 is detected. The value of N of the IJ readout control plane 4 and the interpolation enlargement circuit 6 is controlled so as to gradually become a value of a predetermined reduction ratio N9 when performing camera shake correction.

As described above, according to this embodiment, if the motion vector 2 is detected and there is no camera shake, the captured video is output as is, and if the camera shake is reduced, the camera shake correction state is restored, thereby increasing the resolution of the output image. can be improved. This embodiment can also be performed by microcomputer control.

FIG. 3 shows a block diagram of an image stabilization device according to a third embodiment of the present invention. In FIG. 3, 1 to 7 are the same as those of the conventional example and have the same function, so their explanation will be omitted. 30 is a zoom optical system whose zoom varies depending on the subject; 31 is a COD that converts an image into an electrical signal; and 32 is a camera signal processing circuit that converts the output from the COD into an NTSC signal. 33 is a zoom optical system control circuit that controls the zoom optical system to change the zoom ratio, and a vector quantity verification circuit 34 detects that a motion vector has become less than or equal to a predetermined value and performs calculations. The circuit 35 is controlled.

The arithmetic circuit 35 calculates the zoom ratio controlled by the zoom optical system 30;
It calculates the interpolation enlargement rate of the interpolation enlargement circuit 6 and controls the memory read control circuit 4.

The operation of the image stabilization device of the third embodiment configured as described above will be described below. The YC separated signal enters a motion vector detection circuit 3 and a motion vector is detected. In this case, when the motion vector falls below a predetermined level and the vector amount verification circuit 34 detects it, the arithmetic circuit 35 outputs 1/N of the screen area to perform image stabilization. The zoom ratio of the zoom optical system 30 is controlled to be increased while gradually bringing the reduction ratio N enlarged by the enlargement interpolation circuit 6 closer to 1, so that the output image does not become smaller. The same applies when restoring camera shake correction, and the resolution of the output image can be improved. Next, in the case of returning to image stabilization, the vector amount verification circuit 3 detects that the motion vector was O for a predetermined period and then a motion vector of a predetermined magnitude remained for a predetermined time.
4 is detected, the arithmetic circuit 35 gradually changes the value of N of the memory read control circuit 4 and the interpolation enlargement circuit 6, where N=1, to a predetermined value N, for performing camera shake correction. Accordingly, the zoom ratio is set to 1/N9 and control is performed so that the size of the output screen does not change.

As described above, according to this embodiment, if a motion vector is detected and there is no camera shake, the captured video can be output as is without any change. This embodiment can also be performed by microcomputer control.

FIG. 4 shows a block diagram of an image stabilization device according to a fourth embodiment of the present invention. In FIG. 4, the parts up to the stone 7 are the same as those of the conventional example and have the same function, so their explanation will be omitted. 40 is a zoom optical system whose zoom changes depending on the subject, 41 is a CCD that converts the video signal into an electrical signal, and 42 is an NTSC converter for the output from the COD.
This is a camera signal processing circuit that converts signals into signals. 43 is a zoom optical system control circuit that controls the zoom optical system to change the zoom ratio; an arithmetic circuit 44 is a memory read control circuit that calculates the zoom ratio controlled by the zoom optical system 40, the interpolation magnification rate of the interpolation magnification circuit 6; 4 control is performed. The switch 45 is used to select whether or not to perform image stabilization.

The operation of the image stabilization device of the fourth embodiment configured as described above will be described below. Image stabilization is performed when the switch 45 attached to the exterior is on]
The value of N in the memory readout control circuit 4 that takes out a part of the field image (17N of the entire screen) and the interpolation enlargement circuit 6 that multiplies the screen by N is set to 1, and when the switch 45 is off, the value of N is The arithmetic circuit 44 controls so that it becomes a predetermined value. Also, when the switch 45 attached to the exterior changes from on to off, the arithmetic circuit 44 changes to 1/1/2 of the screen.
The value of N in the memory readout control circuit 4 which reads out N field or frame L7 and the interpolation magnification circuit 6 which multiplies its output by N is gradually set to 1, and conversely, the zoom ratio of the lens is increased. The arithmetic circuit 44 controls so that the output screen is gradually multiplied by N so that there is no change. Further, when the switch 45 is turned on from off, the arithmetic circuit 44 gradually changes the value of N of the memory read control circuit 4 and the interpolation enlargement circuit 6 to 1 so that there is no change in the output screen. As described above, according to this embodiment, camera shake correction is performed when the switch is on, and is not performed when the switch is off, so that the output screen does not change even when the switch state changes.

Effects of the Invention As explained above, when image stabilization is performed when there is camera shake, the resolution of the image deteriorates because one field or part of one frame is taken out and expanded by interpolation. It becomes easier to visually see the object, and as a result, the best output screen can be extracted.

In addition, in the present invention, a circuit is provided to determine whether or not camera shake is occurring, and if camera shake occurs, camera shake correction is performed as before, and if camera shake is not occurring, this is determined based on the vector quantity, and the memory Since the screen is output as it is and the image is output without any interpolation/enlargement operation, the best image can be obtained without any deterioration in image quality due to camera shake correction. The same is true when using a switch to perform or not perform image stabilization; when the switch is on, image stabilization is performed as before, and when the switch is off, the input image becomes the output image as described above, and image deterioration occurs. It won't happen. In these cases, by switching between the image stabilization state and the normal state using the method described above, the zoom ratio of the optical system lens is changed so that the size of the output image is kept constant so that the size of the reproduced image does not change.

The present invention can output the best image quality regardless of the presence of camera shake, and its practical effects are significant.

[Brief explanation of the drawing]

1 is a block diagram of an image stabilization device according to a first embodiment of the present invention, FIG. 2 is a block diagram of an image stabilization device according to a second embodiment of the invention, and FIG. 3 is a block diagram of an image stabilization device according to a second embodiment of the invention. A block diagram of an image stabilization device according to an embodiment, FIG. 4 is a block diagram of an image stabilization device according to a fourth embodiment of the present invention,
FIG. 5 is a block diagram of a conventional image stabilization device, and FIG. 6 is a diagram showing the operation of the image stabilization device. 1... A/D converter, 2... YC separation circuit, 3
...Motion vector detection circuit, 4.Memory readout control circuit, 5.Memory, 6.Interpolation enlargement circuit, 7.D/A converter, 10,2
0. 3 4... Vector quantity checking circuit, 11,2
1.35.44... Arithmetic circuit, 12... Switch circuit, 30.40... Zoom optical system, 3 1. 4
1... COD, 32.42... Camera signal processing circuit, 33.43... Zoom optical system control circuit, 45... Switch.

Claims (3)

[Claims] (1) An image stabilization device that corrects image shaking due to camera shake, comprising: a motion vector detection circuit that detects a motion vector of an image signal; and an image memory that holds at least one field of the image signal; The read address of the image memory is changed based on the motion vector of the motion vector detection circuit,
/N (N is a reduction ratio); a memory readout control circuit that extracts a signal of 1/N portion read from the image memory; and an interpolation enlargement circuit that multiplies the image signal of the 1/N portion read from the image memory and converts it into a full-screen signal; The memory is arranged such that the reduction rate N becomes 1 when the magnitude of the motion vector detected by the motion vector detection circuit is below a predetermined threshold level for a predetermined period of time, and the reduction ratio N becomes the predetermined reduction rate Na when the magnitude exceeds the threshold level. An image stabilization device comprising: a readout control circuit; and an arithmetic circuit that controls an interpolation enlargement circuit. (2) An image stabilization device that corrects image shake caused by camera shake, comprising: a zoom control unit that changes the input image range of the camera; and an image signal that converts the image obtained by the zoom control unit into an image signal. an input means; a motion vector detection circuit that detects a motion vector of an image signal; an image memory that holds at least one field of the image signal; and a read address of the image memory based on the motion vector of the motion vector detection circuit. Change the full screen 1
/N (N is a reduction ratio); a memory readout control circuit that extracts a signal of 1/N portion read from the image memory; and an interpolation enlargement circuit that multiplies the image signal of the 1/N portion read from the image memory and converts it into a full-screen signal; The memory is arranged such that the reduction rate N becomes 1 when the magnitude of the motion vector detected by the motion vector detection circuit is below a predetermined threshold level for a predetermined period of time, and the reduction ratio N becomes the predetermined reduction rate Na when the magnitude exceeds the threshold level. An image stabilization device characterized by comprising an arithmetic circuit that controls a readout control circuit and an interpolation enlargement circuit, and also controls a zoom ratio so that the size of the screen does not change by the zoom control means when enlarging or reducing the screen. Device. (3) Claim 2, wherein the image stabilization device further includes a switch means for switching between the presence and absence of image stabilization.
Image stabilization device described.