JPH04165775A - Blur correction circuit for image pickup device - Google Patents

Abstract

PURPOSE:To output a video signal where the movement of a picture is natural even at the time of pan tilt by restricting a blur detection means output to the correction range preliminarily determined corresponding to the range of the blur of the picture due to camera-shake to give a blur correction means the output of the blur detection means. CONSTITUTION:A correction range control means 12 restricts the output of a blur detection means 24 within the blur correction range to be preliminarily determined based on the output of a focus distance detection means 11 to output it to a blur correction means 23. In short, the output of the blur detection circuit 24 is inputted to the blur correction means 23 while limited to the maximum value of the amount of movement on a screen, the blur correction range is restricted within the range just correcting the amount of the camera-shake. Thus, the blur correction range is restricted and the blur correction range is optimized so as to correct the amount of the camera-shake at all times, the video where the movement of picture is natural can be photographed even when the photographing is performed while utilizing a pan tilt method.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a blur correction circuit in an imaging device, and particularly to a blur correction circuit that can capture a natural image even when capturing an image using a pan/tilt technique. The present invention relates to a blur correction circuit in an imaging device.

[Prior Art] In recent years, a compact VTR-integrated camera that is convenient to carry has been developed, and it has become possible to easily hold it in your hand and take pictures. However, when taking pictures while holding the camera in hand, camera shake inevitably occurs, making the captured screen extremely difficult to see. For this reason, cameras having a blur correction function have been developed.

An example of a conventional blur correction function is shown in FIG. In FIG. 4, the output of the image sensor 21 passes through the blur correction circuit 22,
It is output as a blur-corrected video signal output. The blur correction circuit 22 includes a blur correction means 23 and a blur detection means 2.
4. The blur detection means 24 is for detecting the amount of blur, and the blur correction means 23 is for correcting image blur based on the amount of blur.

The cause of the camera shake is that the camera rotates due to minute vibrations that occur when the camera is held in the hand. This will be explained with reference to FIGS. 7 and 8.

In FIG. 7, light from a subject is imaged onto the image sensor 21 via a lens 51. In FIG. Assume that there is an object being imaged at point A on the optical axis at a certain moment. When the camera has a rotational motion, the next moment the camera rotates by an angle of A
An image is taken at point B, which is h away from the point. When the focal length of the lens is f, the following equation holds true.

h-f, tanb (1) Normally, b times 1, which can be approximated as tanb#b, and h-f-b (2). This h is recognized as image blur on the screen. That is, the image moves by h in FIG.

Therefore, as a blur correction means, it is sufficient to have a function of displaying the above-mentioned images in a smooth manner, thereby eliminating movement on the screen. Note that the blur h can be divided into components hx and hy in both the horizontal and vertical directions, and in reality, image blur is recognized and processed for each of the components thus divided.

An example of the blur detection means 24 is shown in FIG. In FIG. 5, the amount of rotational movement of the camera is detected by an angular velocity sensor 31. In FIG. As examples of angular velocity sensors, a mechanical gyro, a fiber-optic gyro, a tuning fork type angular velocity sensor using a piezoelectric element, etc. are known. A detailed explanation thereof will be omitted. Since the angle signal can be obtained by integrating the angular velocity, the integration circuit 3
The above-mentioned blur angle can be obtained from the output of step 2. By multiplying the angle of blur by the focal length f of the lens 34 in the multiplication circuit 33, h in equation (2) is obtained. lens 3
4, since a zoom lens is usually used, a focal length detection means 35 is provided in connection with the lens 34 to detect the focal length f of the lens 34, and this output is sent to the multiplication circuit 33.
Enter. The output of the multiplication circuit 33 is sent to the gain adjustment circuit 36.
The gain is adjusted by , and sent to the blur correction means 23 as blur data.

An example of the blur correction means 23 is shown in FIG. This is a circuit that shifts and displays images according to the blur data output from the blur detection means. A video signal from the image sensor is converted into a digital signal by an A/D converter 42. The output of A/D converter 42 is stored in field memory 43.

At this time, as shown in FIG. 8, a screen 62 that is slightly smaller than the entire screen 61 that is the imaging range of the image sensor 21 is cut out and stored.

The blur data from the blur detection means 24 described above is converted into digital data by an A/D converter 47 and provided to a memory control circuit 46. The position of the small screen 62 is controlled by the memory control circuit 46 so that it is shifted by the amount of blur h based on this blur correction data, and becomes, for example, a small screen 63. Therefore, from the output of the field memory 43, a small screen with blur correction and no movement due to blur can be obtained. The reason for cutting out the small screen in this way is that the whole screen 61
This is because even if the image is shifted to the area 64 shown by the broken line in FIG. 8, the image will disappear in the area shown by the diagonal line, which is inconvenient. The screen enlargement circuit 44 enlarges the small screen cut out by the field memory 43 to its original size. Screen enlargement circuit 44
The output is converted into an analog signal by the D/A converter 45 and output as a blur-corrected video signal.

[Problems to be Solved by the Invention] As described above, if a camera equipped with a shake correction function is used, the camera shake is corrected even when shooting hand-held, and it is possible to easily shoot still images.

However, when shooting with a TV camera or video camera, you are not only shooting a static screen;
Panning or tilting the camera often occurs.

Here, panning refers to a technique of shooting while rotating the camera left and right without changing the camera position, and tilting refers to a technique of shooting while moving the camera up and down. In such cases, with conventional cameras equipped with image stabilization function,
Since the rotational movement of the camera due to panning and tilting is also corrected, there is a problem in that the screen appears to have very unnatural movements. In other words, for example, when you start turning the camera left or right, the image stabilization function is activated and the screen is still, and if the limit of the correction range of the image stabilization function is exceeded,
This results in unnatural movements such as the image suddenly starting to rotate.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a blur correction circuit for an imaging device that outputs a video signal with natural image movement even when panning and tilting is performed.

[Means for Solving the Problems] The present invention includes a blur detection means for detecting the magnitude of blur of an imaging device, an imaging means for imaging a subject,
A blur correction circuit in an imaging device includes a blur correction means for correcting the position of an image captured by the imaging means based on the output of the blur detection means, and the blur correction circuit corrects the position of the image captured by the imaging means based on the output of the blur detection means. A correction range control means for controlling the blur correction means to limit the correction range to a predetermined correction range corresponding to the range of blur can be seen.

[Effects] In this invention, the image stabilization range is limited and optimized so that only the amount of camera shake is always corrected, so the movement of the image is natural even when panning and tilting. It is possible to output video signals such as:

[Embodiment of the Invention] FIG. 1 is a schematic block diagram showing the configuration of a blur correction circuit according to an embodiment of the invention. In FIG. 1, components similar to those of the conventional example shown in FIG. 4 are given the same reference numerals, and their explanations will be omitted.

The blur correction circuit 10 shown in FIG.
1 and a correction range control means 12.

The focus detection means 11 is for detecting the focal length of the lens. The correction range control means 12 limits the output of the blur detection means 24 to a predetermined blur correction range based on the output of the focal length detection means 11.
This is what is output to.

Next, the blur correction range will be explained. The amount of camera shake when taking a picture while holding a TV camera in your hand varies depending on the size and weight of the camera, and the individual differences of the photographer, but the inventor's experimental results show that the maximum rotation angle that the camera undergoes due to camera shake is The value ±biA8 was approximately ±0.3 degrees. Therefore, it is sufficient to correct camera shake within an angle of approximately ±0.degree. to 4 degrees. The amount of movement on the screen at this time is ±h1. l
Assuming AX, from equation (2), ±hhAx−fX(±br+Ax) (3
).

In the conventional example, since there is no shake correction range control means, the correction is performed up to the upper limit determined by the detection ability of the shake detection means or the correction ability of the shake correction means. The movement of the image was unnatural, but the output of the shake detection means 24 was calculated using the above formula (
3)±h.

If the image is limited to AX and inputted to the blur correction means 23, the blur correction range is limited to just the range that corrects the amount of camera shake, and the movement of the image becomes natural when panning and tilting is performed.

An example of the blur correction control means is shown in FIG. In FIG. 2, blur data from the blur detection means 24 is outputted through a + side limiting circuit 72 and a one side limiting circuit 73. The multiplier circuit 75 multiplies the focal length data f by the positive maximum value of the blur angle + bl - 1A, provides the output +h AX to the + side limiting circuit 72, and sets the maximum value of the blur data to +hT'l A
Limit it to X. The multiplication circuit 76 inputs focal length data f
is multiplied by the negative maximum value of the shake angle - k) M A x,
The output -hMAX is given to the one-side limiting circuit 73 to limit the negative maximum value of the blur data to -hhAX. As a result, the blur data input/output characteristics of the correction range control means 12 are as shown in FIG. In other words, the deflection data input is 0.
From ±hrI A h,,lA X.

As described above, the blur correction range is limited to just the amount of camera shake corrected.

The blur correction circuit 10 shown in FIG. 1 is provided with a focal length detection means 11, but in this embodiment, a focal length detection means 35 is provided in the blur detection means 24, and this focal length detection means 35 is provided in the blur detection means 24. Detection means 35 and focal length detection means 1
1 can be shared. Note that the blur correction means and blur detection means used in the embodiments of the present invention are merely examples, and it goes without saying that the present invention can be applied to other blur correction means and blur detection means.

[Effects of the Invention] As described above, according to the present invention, the image stabilization range is limited and optimized so that only the amount of camera shake is always corrected. Even when shooting, images with natural movement can be captured.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a schematic block diagram showing the configuration of the correction range control means shown in FIG. 1. FIG. 3 is a graph showing the human output characteristics of the correction range control means shown in FIG. FIG. 4 is a schematic block diagram showing the configuration of a conventional blur correction circuit. FIG. 5 is a schematic block diagram showing the configuration of the blur correction means shown in FIG. 4. FIG. 6 is a schematic block diagram showing the configuration of the blur detection means shown in FIG. 4. FIGS. 7 and 8 are diagrams for explaining the causes of blurring. In the figure, 10 is a blur correction circuit, 11 is a focal length detection means, 12 is a correction range control means, 21 is an image sensor, and 23
24 shows a blurring correction means, and 24 shows a blurring detection means.

Claims (1)

[Scope of Claims] A blur detection means for detecting the magnitude of blur of an imaging device; an imaging means for imaging a subject; and a position of an image captured by the imaging means as an output of the blur detection means. A blur correction circuit in an imaging device, comprising a blur correction means for correcting based on camera shake, wherein the output of the blur detection means is limited to a predetermined correction range corresponding to a range of image blur that may occur due to camera shake. A blur correction circuit in an imaging apparatus, comprising a correction range control means for controlling the blur correction means so as to apply the correction range to the blur correction means.