JP2804644B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus using a solid-state image pickup device, and more particularly to an image pickup device capable of correcting a camera shake by moving a scanning region of the solid-state image pickup device.

[0002]

2. Description of the Related Art In recent years, with the spread of video-integrated cameras, the functions required by users have become diversified. In particular, a camera shake correction function for correcting image shaking due to camera shake has attracted attention. As a method of realizing the camera shake correction function, a method of using a solid-state imaging device having a larger number of pixels than necessary for generating a standard video signal (for example, JP-A-2-231873), , A method using electronic zoom (Morimura et al., "Pure electronic image shaking correction system" Technical Report of the Institute of Television Engineers of Japan, Vol. 1)
5, No. 7pp. 43-48) and the like have been proposed.

The point of the prior art is that an area having a smaller number of pixels than an effective pixel area composed of effective pixels arranged in a matrix on a light receiving surface of a solid-state image sensor is a scanning area. When the image is shaken so as to extract a signal, the scanning area is moved so as to cancel the image shake. That is, the number of effective pixel regions is N _V in the vertical direction and N _{H in} the horizontal direction.
If the scanning region is composed of n _V (vertical) × n _H (horizontal) pixels, that is, N _V × N _H pixels, and ± _V in the vertical direction in pixel units with respect to this scanning region.
(N _V −n _V ) / 2, ± (N _H −n _H ) / 2 movement range (that is, correction range) in the horizontal direction can be secured, and the scanning area is within the movement range by the same amount as the image shake. By moving the image, it is possible to remove the fluctuation of the image. Here, in the former conventional example, the number of pixels of a general image sensor corresponds to n _V × n _H, and in the latter conventional example, the number of pixels of a general image sensor corresponds to N _V × N _H. .

[0004]

By the way, in order to secure the above-mentioned correction range as much as possible, it is desirable that the center of the scanning area be automatically made coincident with the center of the effective pixel area when the image is not shaken. However, for example, when the fluctuation of the image is strong in one direction such as panning, the scanning area gradually moves from the end of the effective pixel area toward the center when the fluctuation stops. For this reason, on the playback screen, the image does not change with panning, but changes so as to follow the panning with a delay, giving a very unnatural feeling.

An object of the present invention is to provide an image pickup apparatus which can solve such a problem and can prevent an unnatural image display on a reproduction screen even if there is a large image fluctuation in one direction. .

[0006]

In order to achieve the above object, the present invention specifies a moving amount of a scanning region of an image pickup device and sets a movable region of the scanning region within an effective pixel region of the image pickup device. A scanning area designating circuit for limiting, when the fluctuation of the subject image on the light receiving surface of the image sensor is large, the scan area designating circuit increases the movable area of the scanning area or detects a detected optical zoom. Focal length of lens (F value)
, The movable range of the scanning area is changed.

[0007]

The movable range of the scanning area is set to be narrow in advance. In this case, when the fluctuation of the image is settled, the center of the scanning area reaches the center of the effective pixel area by slightly moving. When the fluctuation of the image is large, the movable range of the scanning area is widened, and as the fluctuation of the image is reduced, the movable range of the scanning area is narrowed, and the fluctuation of the image on the reproduction screen is suppressed.

Further, as the F value becomes smaller, that is, when the movable range of the scanning area is narrowed as the zoom approaches the wide end, if the magnitude of the image fluctuation is fixed, the F value becomes smaller. As the swing width of the image becomes smaller, the shake of the image is suppressed even if the movable range of the scanning area is narrowed, and the movable range of the scanning area is near the wide end where there are many opportunities for performing the panning operation. Is reduced, the center of the scanning area moves to the center of the effective pixel area only by slightly moving when the shaking of the image stops. Therefore, an unnatural image motion that follows the panning with a delay is reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an imaging apparatus according to the present invention, wherein 1 is a zoom lens, 2 is an F value detection circuit, 3 is an image sensor, 3a is an effective pixel area, 3b is a scanning area, Is a time axis conversion circuit, 4a is a line memory, 4b is a memory control circuit, 5 is a signal processing circuit, 6 is a scanning pulse generation circuit, 7 is an output terminal, 8 is a scanning area designation circuit, 8a is a movable range limiting circuit, 8b Is a scanning area calculation circuit, and 9 is a motion detection circuit.

In FIG. 1, light from a subject is irradiated on an image sensor through a zoom lens 1.
A subject image is formed on an effective pixel area 3a in which pixels are arranged in a trix shape. In the image sensor 3, the effective pixel area 3a is generated by the scan pulse A from the scan pulse generation circuit 6.
The scanning area 3b having a predetermined size is scanned and an electric signal is read. The output signal of the image sensor 3 is processed by the time axis conversion circuit 4 and the signal processing circuit 5 and output from the output terminal 7 as a video signal.

[0011] motion detecting circuit 9 detects a vertical motion amount M _V and horizontal motion amount M _H of the imaging apparatus due to camera shake. The scanning area designating circuit 8 comprises a movable range limiting circuit 8a and a scanning area calculating circuit 8b.
These motion amount M _V, vertical movement amount m _V scanning area 3b in the effective pixel region 3a from M _H, horizontal motion amount m _H
Is calculated, and the movable range limiting circuit 8a calculates the motion amount m _V ,
m _H and F of the zoom lens 1 detected by the F value detection circuit 2
Forming the values (focal length) vertical scanning region specifying signal determines the actual moving amount of the scanning area 3b from the m _'V and the horizontal scanning area designation signal m' _H.

[0012] scan pulse generating circuit 6 'supplies the scan pulse A corresponding to _V on the image pickup device 3, the vertical scanning area designation signal m the scanning area 3b in the imaging element 3' the vertical scanning area designation signal m _V Move to the position specified by. The output signal of the image sensor 3 is supplied to the time axis conversion circuit 4. The time axis conversion circuit 4 includes a line memory 4a and a memory control circuit 4b, and the output signal of the image sensor 3 is written to and read from the line memory 4a by the memory control circuit 4b. further, reading is performed from the line memory 4a at a timing corresponding to the horizontal scanning area designation signal m _'H from the movable range limiting circuit 8a.
The operation of the time base converting circuit 4, the scanning region 3b in the imaging element 3 will move to the horizontal position specified by the horizontal scanning area designation signal m _'H.

The movement of the scanning area 3b in the vertical and horizontal directions is the same distance and in the opposite direction as the movement of the image pickup device 3 due to camera shake, thereby eliminating image shaking due to camera shake.

When the motion amounts M _V and M _H are zero (there is no image fluctuation), the scanning area designating circuit 8 determines that the center of the scanning area 3b is perpendicular to the direction coincident with the center of the effective pixel area 3a. The horizontal movement amounts m _V and m _H are gradually changed. Also, depending on whether the center of the scanning area 3b moves upward or downward with respect to the center of the effective pixel area 3a, or moves to the left or right, the vertical movement amount m _V ,
The sign of the horizontal movement amount m _H is different in sign.

Next, the operation of the movable range limiting circuit 8a in FIG. 1 will be described with reference to FIG. For the sake of simplicity, the vertical and horizontal movement amounts m _V and m _H and the maximum movement amounts m _Vmax and m _Hmax are all positive.

First, the F value of the zoom lens 1 detected by the F value detection circuit 2 is fetched (step 200).
From the values, the maximum values m _Vmax and m _Hmax of the scanning area 3b that can be moved in the vertical and horizontal directions are obtained (step 201). Thereafter, the vertical and horizontal movement amounts m _V and m _H are fetched from the scanning area calculation circuit 8b (step 202), and the vertical movement amount m _V and the maximum value m _Vmax are _converted into the horizontal movement amount m _{H. Is} compared with the maximum value m _Hmax (step 203). Then, the image shake due to camera shake is small, and m _V <m _Vmax
If m _H <m _Hmax , the scanning pulse generation circuit 6 sets the vertical motion amount m _V as the vertical scanning area designation signal m ′ _V.
And the horizontal movement amount m _H as a horizontal scanning area designation signal m ′ _H , the memory control circuit 4b of the time axis conversion circuit 4
(Steps 204 and 205). This allows
The scanning area 3b moves following the image sway, and the sway on the reproduction screen disappears.

On the other hand, there is a large image fluctuation in the vertical direction due to panning or the like, and m _H <m _Hmax .
When m _V ≧ m _Vmax , the horizontal movement amount m _H is supplied to the memory control circuit 4b of the time axis conversion circuit 4 as the horizontal scanning region designation signal m ′ _H , but the vertical scanning region designation signal m ′ _{V Is} supplied to the scanning pulse generation circuit 6 as the maximum value m _Vmax of the vertical movement amount. Thereby, the scanning area 3
The amount of vertical movement of b is limited. Conversely, there is a large horizontal image fluctuation due to panning, etc.
If m _V <m _Vmax but m _H ≧ m _Hmax , the vertical motion amount m _V is supplied to the scanning pulse generation circuit 6 as the vertical scanning area designating signal m ′ _V , and the horizontal scanning area designating signal m ′
The maximum value m _Hmax of the horizontal movement amount is supplied to the memory control circuit 4 b of the time axis conversion circuit 4 as _H. This is
The horizontal movement amount of the scanning area 3b is limited. Of course m
_{When V} ≧ m _Vmax and m _H ≧ m _Hmax , the vertical scanning region designation signal m ′ _V is the maximum value m of the vertical movement amount.
A scanning pulse generating circuit 6 to _Vmax, the horizontal scanning area designation signal m 'supplied respectively to the horizontal direction of the memory control circuit 4b of the motion amount of the maximum value m _Hmax time axis converting circuit 4 as _H (or, step 203, 206 , 205).

As described above, when the fluctuation of the image is large, the amount of movement of the scanning area 3b is limited. When the fluctuation disappears, the center of the scanning area 3b immediately returns to the center of the effective pixel area 3a. That is, at the time of panning, the image changes following this panning, and an image change due to natural panning is obtained.

Also, the maximum value m of these vertical movement amounts
_Vmax, the horizontal movement of m _Hmax Gaz - zoom lens 1 of F
As shown in FIG. 3, the maximum value m _VW and m _HW at the wide end and the maximum value m at the tele end are set as shown in FIG.
_If the relationship between _VT and m _HT is m _VW <m _VT , m _HW <m _HT , the movable range of the scanning area 3b can be narrowed as approaching the wide end. Since the panning operation is often performed near the wide end, in this embodiment, the delay in image change on the playback screen due to panning is reduced.

FIG. 4 shows a movable range limiting circuit 8a in FIG.
7 is an example of a flowchart showing another example of operation. This operation is different from the operation shown in FIG.
08 is added, and when the vertical and horizontal movement amounts m _V and m _H are larger than the maximum values m _Vmax and m _Hmax , respectively, that is, when a large fluctuation of the image occurs, the preset value m _VP
The movable range of the scanning region 3b is gradually _{increased by LUS} and _mHPLUS to enhance the image shake correction effect. When the image swing is reduced, the movable range of the scanning region 3b is narrowed.

Step 401 expands the movable range, and step 402 determines whether or not the enlarged movable range is out of the range shown in FIG. If not, when the motion amounts m _V and m _H are within the enlarged movement range (step 405), the processing of step 204 is performed. When the enlarged movable range is out of the range of FIG. 3, the movable range is set to the range of FIG. 3 (step 403). Step 407 is the motion amount m _V , m _H
Is larger than the enlarged movement range, the same processing as in step 206 of FIG. 2 is performed.

The movable range limiting circuit 8a or the scanning area designating circuit 8 for performing the operations shown in FIGS. 2 and 4 can be constituted by hardware such as an adder, a multiplier and a comparator. The above operation can also be realized by software.

FIG. 5 is a block diagram showing another embodiment of the image pickup apparatus according to the present invention.
Reference numeral a 'denotes a movable range limiting circuit, and portions corresponding to those in FIG.

In FIG. 1, the macro detection circuit 10 is
It is detected whether or not the zoom lens 1 has entered the macro area. If the zoom lens 1 is in the macro area, the detection signal M
_{The acro} is supplied to the movable range limiting circuit 8a 'of the scanning area designating circuit 8 to stop the image shaking correction operation. When the zoom lens 1 is not in the macro area, an image shake correction operation similar to that in the embodiment shown in FIG. 1 is performed. In the macro area, in general, shooting is performed in close proximity to the subject.
Rather, it is better to stop the image shake correction operation. This is the same for the first and second embodiments.

FIG. 6 is a block diagram showing still another embodiment of the image pickup apparatus according to the present invention. In FIG. 6, reference numeral 8a "denotes a movable range limiting circuit, and portions corresponding to those in FIG.

This embodiment is characterized in that the maximum values m _Vmax and m _Hmax of the vertical and horizontal movement amounts of the scanning area are set independently of the F-number of the zoom lens as shown in FIG. This is different from the embodiment. Even in this case, even if the image shakes greatly due to panning or the like, the movable range of the scanning region 3b is limited, so that the delay of the image change is reduced. FIG. 8 is a flowchart showing the operation of the movable range limiting circuit 8a "in FIG.
Vertical scanning region 3b instead of 00,201, steps 700 to initialize are provided maximum value m _Vmax horizontal motion amount, the m _Hmax. Also in this embodiment, FIG.
An operation flow for gradually expanding the movable range of the scanning area 3b in the above may be added. In this embodiment, since an F value detection circuit or the like is not required, the system can be downsized.

[0027]

As described above, according to the present invention,
Because the movable range of the scanning area can be narrowed while maintaining the image distortion correction effect, even if a large movable range is set for large image distortion such as panning, the image distortion can be settled and movable Since the range is narrowed, the center of the scanning area also quickly coincides with the center of the effective pixel area, and unnatural movements such as an image on the reproduction screen following with a delay are greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an imaging device according to the present invention.

FIG. 2 is a flowchart showing an example of the operation of the movable range limiting circuit in FIG.

FIG. 3 is a diagram showing an example of calculating maximum values m _Vmax and m _Hmax of the amount of movement of a scanning area in the operation shown in FIG. 2;

FIG. 4 is a flowchart showing another example of the operation of the movable range limiting circuit in FIG. 1;

FIG. 5 is a block diagram showing another embodiment of the imaging apparatus according to the present invention.

FIG. 6 is a block diagram showing still another embodiment of the imaging apparatus according to the present invention.

FIG. 7 is a diagram showing an example of calculating the maximum values m _Vmax and m _Hmax of the motion amount of the scanning area in the embodiment shown in FIG. 6;

8 is a flowchart showing an example of the operation of the movable range limiting circuit in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Zoom lens 2 F value detection circuit 3 Image sensor 3a Effective pixel area 3b Scanning area 4 Time axis conversion circuit 4a Line memory 4b Memory control circuit 5 Signal processing circuit 6 Scan pulse generation circuit 8 Scanning area designation circuit 8a, 8a ', 8a ″ movable range limiting circuit 8b scanning area calculating circuit 9 motion detecting circuit 10 macro detecting circuit

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Michio Masuda 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. Hitachi, Ltd. Visual Media Research Laboratory (58) Field surveyed (Int. Cl. ⁶ , DB name) H04N 5 / 30-5/335

Claims (4)

(57) [Claims] 1. An image pickup apparatus wherein an operation area set in an effective pixel area on a light receiving surface of an image sensor is moved in accordance with a shake of an image to correct the shake of the image. An imaging apparatus characterized in that a first means for setting a movable range of the operation area is provided within the apparatus, and the movement of the operation area can be restricted within the movable range. 2. The apparatus according to claim 1, further comprising a second unit for detecting a focal length of the zoom lens, wherein the first unit comprises:
An imaging apparatus, wherein the size of the movable range is determined according to the detected focal length. 3. The imaging apparatus according to claim 1, wherein the movable range increases when the image sway is large, and the movable range decreases when the image sway is small. 4. The zoom lens according to claim 1, wherein the zoom lens is capable of macro photography, and a macro detection circuit is provided for detecting whether the zoom lens is in a macro photography state. An imaging apparatus, wherein the movement of the scanning area is stopped at a certain time.