JPH0391728A - Camera blurring detector - Google Patents

Abstract

PURPOSE:To detect the presence or absence of camera blurring in an extremely short time by constituting a detector so as to detect the camera blurring by using a part of a photoelectric convertion element string for autofocusing (AF). CONSTITUTION:Charge accumulating time t2 is decided based on a detecting signal from the partly detecting means 20B of a brightness monitor 20. When t2<t1, information M1 concerning photodiodes Ri - Rk corresponding to the focus detecting region detected by brightness by the partly detecting means 20B of the brightness monitor 20 among whole transfer signals transferred to a controller 19 in sequence through a voltage amplifier 17 is stored in the storage region M of a memory part 19B. After the lapse of the fixed time, information corresponding to photodiodes R1 - Rn, L1 - Ln is integrated again at accumulating electrode groups 13 and 14 and is stored in the storing region M2 of the memory part 19B. Then, the two pieces of information stored in the storage regions M1 and M2 are compared by the comparing part 19C of a controller 19, and when the difference is the prescribed quantity of above, the condition is judged as the camera blurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Scope of Industrial Application] The present invention relates to a camera shake detection device for a camera, and particularly to a camera shake detection device for a camera having an autofocus device using a charge-coupled device.

[Conventional technology]

When taking pictures while holding the camera in your hand, if the shooting speed is slow, you will often get blurred pictures due to camera shake. In order to prevent such camera limitations, conventional aperture-priority automatic exposure control cameras
2. Description of the Related Art Cameras are known that are equipped with a camera shake limit warning device that issues a warning by blinking a light emitting element or making a buzzer sound when the shutter speed determined from the subject brightness measured by photometry becomes slower than a predetermined value. Furthermore, since this camera shake limit also changes depending on the focal length of the photographic lens, there is also a known camera with a camera shake limit warning device that is configured to change the camera shake limit of the shutter speed at which a warning is issued depending on the focal length of the photographic lens. be. However, since the limit of the shutter speed that causes camera shake varies depending on the user's skill level and how the camera is held, the camera shake limit warning device described above does not allow camera shake to occur even when issuing a warning. However, the reliability of this method was poor, as it sometimes resulted in blurred photographs, and conversely, camera shake could occur even when no warning was issued.

In order to solve the drawbacks of this conventional device, we developed a camera autofocus system (hereinafter abbreviated as AFJ) to reduce the camera shake phenomenon.
A camera shake detection device that uses a charge-coupled device (hereinafter referred to as RCCD) is disclosed, for example, in
It is disclosed in Japanese Patent No. 2732, etc., and is already publicly known.

The camera shake detection device disclosed in this publication is for AP C
Focus detection is performed once using the output signal of the CD, the signal at that time is memorized, and then a second focus detection is performed automatically after a predetermined period of time has elapsed, and the presence or absence of camera shake is detected from the difference between the two output signals. Configured to detect.

[Problem to be solved by the invention]

In general, in camera shake detection devices using AF devices, A
In F mode, it is advantageous to use more output signals to improve detection accuracy, but when detecting camera shake, it is only necessary to determine whether there is camera shake, and based on that determination, it goes without saying that a camera shake warning can be issued, for example, with a shirt button. The following actions are often required, such as canceling the release, increasing the shutter speed, switching to flash photography, etc., and it is desirable to process information in a shorter time. However, the camera shake detection device disclosed in the above publication uses an output signal with the same quality and quantity for focus detection and camera shake detection, and the time required for camera shake detection is relatively long, resulting in high-speed detection. The problem was that it was difficult.

Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional camera shake detection device using COD for AP, and to achieve a detection accuracy that is significantly improved over the conventional camera shake detection device using an AF CCD in an extremely short time. The object of the present invention is to provide an image stabilization detection device.

[Means to solve the problem]

In order to achieve the above object, a camera shake detection device according to the present invention is provided in a camera equipped with an automatic focusing device equipped with a charge-coupled device having a photoelectric conversion element array that photoelectrically converts light from a subject. an amplifier that voltage-amplifies the transfer signal sequentially transferred from the element; an overall detection means that detects the subject brightness of the entire focus detection area when detecting the subject distance; and a part of the subject brightness within the focus detection area when detecting camera shake. A brightness monitor having a partial detection means, a transfer signal from the charge-coupled device which is sequentially transferred via an amplifier, and detection No. 13 from the brightness monitor are inputted to determine the charge accumulation time of the charge-coupled device and the output of the amplifier. A control means for controlling the amplification degree and a charge accumulation time for detecting a subject distance determined based on a detection signal from a brightness monitor and a charge accumulation time for detecting camera shake, whichever is shorter. Of the total transfer signals transferred via the amplifier, a portion of the transfer signals corresponding to the luminance detection area of the partial detection means, and after a predetermined delay time {all transfer signals transferred via the amplifier again. The means for solving the problem includes a comparison means for determining the presence or absence of camera shake by comparing the signal with a time-delayed transfer signal corresponding to the luminance detection area of the partial detection means.

In the above amplifier, the amount of gain is controlled via the gain controller so as to make full use of the dynamic range by comparing the level range of the signal to be transferred to the control means and the dynamic range of the processing of the control means. It is good to take precautions like this.

The control means may include the comparison means, memory means for storing at least each of the transfer signals, and a timer for controlling the charge accumulation time of the charge-coupled device based on the detection signal from the brightness monitor. It is desirable that the

Furthermore, when the charge accumulation time during subject distance detection in which the timer controls the charge-coupled device is smaller than the charge accumulation time during camera shake detection, the above comparison means compares the partial transfer signal and the predetermined delay time during subject distance detection when the timer controls the charge-coupled device. It is effective to compare the above-mentioned time-delayed transfer signal to determine the presence or absence of camera shake.

[For production]

In the camera shake detection device configured as described above,
In the case of automatic focusing, first, the charge accumulation time t when detecting the object distance is determined based on the detection signal from the overall detection means of the brightness monitor, and then charge coupling is performed at this charge accumulation time t. Charge is accumulated by the element, and the accumulated charge is sequentially transferred to a control device via a voltage amplifier, and a focusing operation is performed in accordance with all the transferred signals.

In the case of camera shake detection, a charge accumulation time t, is determined based on a detection signal from a part of the detection means of the brightness monitor, and 1
．． <1. When , the charge is accumulated during this charge accumulation time t2,
Among all the transfer signals sequentially transferred to the control device via the voltage amplifier, a portion of the transfer signal m from a portion of the photodiode corresponding to a portion of the focus detection area whose brightness is detected by a portion of the detection means of the brightness monitor is m. , and, after a predetermined delay time, the charge accumulation time t, is accumulated again, and among the total transfer signals that are sequentially transferred to the control device via the voltage amplifier, a part of the detection means of the brightness monitor detects the brightness of the focus detection area. The comparison means compares the partial transfer signal m, from the corresponding part of the photodiode with the partial transfer signal m, from a part of the photodiode corresponding to the part, and when the difference between m and m is larger than a predetermined value, it is determined that there is a camera shake.

On the other hand, when jz>j+, the photo signal corresponding to the luminance detection area of the above-mentioned partial detection means is accumulated during the charge accumulation time during object distance detection and transferred via the amplifier. Partial transfer signal m from part of diode
0 and the above mt using a comparison means, m. When the difference between and m2 is larger than a predetermined value, it is determined that there is a hand strain.

〔Example〕

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a schematic structure of an embodiment of the present invention, and FIG. 2 is a correlation method (positioning) showing an example of an imaging optical system when the present invention is applied to a single-lens reflex camera. FIG. 2 is an optical system layout diagram of an AF device using a phase difference detection method.

In FIG. 2, a movable mirror 2 is obliquely installed on the optical path between the photographic lens I and the focal plane to reflect the light beam from the subject that has passed through the photographic lens I and guide it to a finder optical system (not shown). A part of the luminous flux from the subject that has passed through the movable mirror 2 is first focused on the focal plane, passes through the condenser lens 3, and is further focused on the light receiving section of the CCD 10 by a pair of imaging lenses 4.5. 2m long photoelectric conversion element array 1
The same subject image is formed on 1 and 12, respectively.

As shown in Fig. 1, the CCU to has two photoelectric conversion elements array 1 that receive light from an object and generate a light flow.
1. 12, 2 (storage electrode group 13, 14 of II, and a shift gate opened at a predetermined timing) 15, which integrates the respective photocurrents corresponding to these two photoelectric conversion element arrays 11 and 12, and an analog shift register. 16, and the charges integrated by the storage electrode groups 13 and 14 are horizontally transferred so as to be transferred in parallel to the analog shift register l6 via the shift gate l5.

One photoelectric conversion element row l1 has n photodiodes R.
,, R, ~Rn, and the other photoelectric conversion element array l2
There are also n photodiodes t, I. It is composed of t, t~Ln.

Each charge is sequentially transferred from the analog shift register 16, converted into a voltage by a converter l7, further amplified by a buffer amplifier l8, and input to the processing/control unit i[19. This processing/control device W119 includes storage electrode group 13.
14, a memory section 19B for storing transferred signals, and a comparison section 19C for determining camera shake. In addition, storage electrode group 13. A brightness monitor 20 that monitors the brightness of the subject in order to determine the accumulation time of 14 and the amplification degree of the buffer amplifier 18 is connected to the overall detection unit 2OA that detects the brightness of the entire focus detection area on the subject side necessary for focus detection, and the overall detection unit 2OA that detects camera shake. It has a partial detection gE20B that detects part of the subject brightness corresponding to the photodiodes Ri-Rk necessary for detection, and each detects the brightness and processes and controls the i! 19. The gain controller 2l is configured to control the amplification degree of the buffer amplifier l8 based on the signal from the processing and control device 19, and furthermore,
The focus adjustment device 22 is also configured to be controlled by a signal from the processing and control device 19.

The processing/control device 19 includes a focus lock switch Sw that stops automatic focusing when turned on manually, and a focus lock switch that turns on and starts power supply to each part of the camera when the release button 6 is pressed halfway. The release switch Sw+ is turned on when the push switch Sw+ and the release button 6 are fully pressed. is provided.

Next, an overview of a series of photographing operations including detection of hand strain in a single-lens reflex camera will be explained using the flowchart of FIG.

3rd rI! In J, when the release button 6 is pressed halfway and the halfway press switch Sw+ is turned on, the automatic focusing operation shown in FIG. 4, which will be described later, is performed (step 3401), and it is determined whether or not the focusing operation is completed. (Step 3402)
If the focusing operation has not been completed, it is determined whether the release button 6 continues to be pressed halfway (step 3403).

In this step S403, if the half-press state continues, the process returns to step S401, and if the half-press operation is canceled, the operation ends.

When it is determined in step 3402 that the focusing operation is completed, it is then determined whether the release button 6 is fully pressed and the fully pressed switch Sw is turned on (step 3404), and it is determined whether the fully pressed switch Sw is turned on or not. If not, it is determined again whether or not the half-pressed state continues m times (step 3405). In this step S405, when the half-press operation is released, the operation is ended, and when the half-press state continues for m, a focus lock operation is applied and the focus lock switch Sw. It is determined whether or not is on (step 540θ). This step 54
In 0B, if the focus lock switch Swe is on, the process returns to step 3404 and step 34
01 focusing operation is prohibited, and when it is off, the first step 3
Returning to step S401, the focusing operation in step S401 is permitted.

On the other hand, if it is determined in step S404 that the release button 6 is fully pressed, camera shake detection as shown in FIG. ), when it is determined that no camera shake has occurred, the movable mirror 2 is raised (step S409), the shutter is subsequently opened and closed to perform exposure (step 3410), and when the exposure is completed, the operation ends.

If it is determined in step 8408 that camera shake has occurred, a camera shake warning is issued by flashing a light emitting element or by a buzzer (step S411), and the shutter speed is further shifted to a high enough speed to prevent blurring of the photograph. At the same time, the aperture value is shifted to the larger aperture side by an amount commensurate with this (step S412). Next step S4
13, whether proper exposure can be obtained even if the shutter speed is increased in step S412 (because the brightness of the subject is low, even if the aperture is fully opened, the shutter speed calculated in step S412 will result in underexposure. (step S413) is determined (step S413).
If proper exposure is obtained, proceed to step S409,
If it is obtained, the operation ends.

FIG. 4 is a flowchart showing the automatic focusing operation. The automatic fishing operation in the embodiment of the present invention shown in FIG. 1 will be described below based on FIG. 4.

The overall detection unit 2OA of the brightness monitor 20 is obtained by averaging the brightness of the subject imaged within the focus detection area that is received by one photoelectric conversion element array 1l via one imaging lens 4. Output a signal. Processing/control unit ii119
The brightness monitor 20 is set so that the charge signals sequentially transferred from the Anaguchi Gunft register 16 are at appropriate levels.
A charge accumulation time t for focus detection is determined based on information from the overall detection unit 2OA (step SLOL).

At this time, the appropriate level of the charge signal is determined as an amount large enough to ignore circuit noise when converted to voltage in conversion 517.

When the accumulation time t for focus detection is determined in step stot, the photocurrent generated in the charge conversion element arrays 1l and 12 is transferred to the corresponding storage electrode group 13. 14 and accumulated for time t1 (step S1
02). Each of the accumulated charges is transferred in parallel to the analog shift register 16 via a shift gate l5 that is opened at a predetermined timing, and then sequentially transferred from the analog shift register l6 to the conversion 517 (step S
103). The charges sequentially transferred from the analog shift register l6 are converted into voltage at the conversion word 17, then amplified by the buffer amplifier 18 (step 3104), and input to the processing/control unit ii1.9.

The total signals input to the processing and control unit M19 corresponding to each charge flow generated in the charge conversion element rows 1 and 12 are as follows:
The data is read and stored in the memory part 19B (step S105). Further, a known focusing operation is performed based on this signal (step 5106), and the series of automatic focusing routines is completed.

FIG. 5 is a flowchart showing the camera shake detection operation.

Hereinafter, based on FIG. 5, the camera shake detection operation in the embodiment of the present invention shown in FIG. 1 will be explained.

First, in the automatic focusing operation shown in FIG. 4, the photodiodes R1 to R[I and L. - From the information corresponding to Ln, only the information corresponding to the photodiodes Rt-Rk located approximately in the center in one photoelectric conversion element array ll (collectively referred to as m.) is read out, and a portion of the memory is read out. Store in the storage area of 19B (step 3201)
.

Subsequently, the signal level range of the information m0 corresponding to the photodiodes Ri-Rk stored in step S201 is compared with the extent to which the processing dynamic range of the processing/control unit R19 is applied, and this dynamic range is fully used. The gain amount (the degree of amplification of the voltage amplifier 17 controlled via the gain controller 21) and the accumulation time t for camera shake detection are determined as follows (step S20).
2). Furthermore, part of the detection section 20 of the brightness monitor 20
B outputs the subject brightness information corresponding only to the photodiodes Ri-Rk. When the subject brightness information from the partial detection unit 20B indicates higher brightness than the previous full detection unit 20A, charge accumulation becomes faster by that amount, so it takes an accumulation time to accumulate a predetermined amount of charge. tx can be short. Therefore, the gain amount is determined in consideration of the fact that the voltage to be amplified changes due to the shortening of the accumulation time.

When the accumulation time t2 is determined in step S202, it is compared with the accumulation time t determined in step SIOI during the focusing operation (step 3203). When t,<t, the gain amount is large, which means that small differences in photodiode levels can be more magnified for comparison, and highly accurate detection is possible. T! <1, one photodiode R. -Rn and the other photodiodes L, ~'Ln are stored in the storage electrode group 13. 14 and accumulated for time t, respectively (step S204).

Each of the accumulated charges is transferred to an analog shift register 16 via a shift gate l5 that is opened at a predetermined timing.
is transferred in parallel to the analog shift register l6.
are sequentially transferred to the converter 17 (snap 3205)
. The charges sequentially transferred from the analog shift register l6 are converted into voltage by the converter l7, then amplified by the buffer amplifier l8 (step S206), input to the processing/control unit 1119, and transferred to the photodiode Ri=Rk. Only the corresponding information (collectively referred to as nl.) is read and processed, and a part of the memory 19B is
(Step S207).

In step S207, the photodiodes Ri to R
The information ml corresponding to k is stored in the storage area M of the memory part 19B.
．． After being memorized, wait for a certain amount of time to pass (Step!
i208). Note that in step 8208, the waiting time may be changed depending on the shutter speed, instead of a fixed time, such as waiting for a short time if the separately determined shutter speed is high, or waiting for a long time if the shutter speed is low. Again, information corresponding to the photodiodes R1 to Rn, l, +-Ln is stored in the storage electrode group 13. 14 and accumulated for time t2 (step 3209). Each of the accumulated charges is transferred in parallel to the analog shift register 16 via a shift gate l5 that is opened at a predetermined timing, and then sequentially transferred from the analog shift register l6 to the converter 17 (step S210).

The charges sequentially transferred from the analog shift register 16 are converted into voltage by the converter l7, and then transferred to the buffer 7 and the amplifier 1.
8 (step S211), and the processing/control device i
Only the information corresponding to the photodiodes Ri-Rk (collectively referred to as m2) inputted to tl9 is read and processed again, and stored in the storage area M of the memory part 19[l (step 52+2). ). However, in this case, the same gain and accumulation time as used when determining m are used.

In step S212, photodiodes Ri to R
Information m corresponding to k is stored in the storage area M of the memory part 19B.
2, the comparison unit 19C of the processing/control device 19 compares the two pieces of information stored in the storage areas M and M (step S213), and if the difference is greater than or equal to a predetermined amount. If there is, it is determined as camera shake (step 32).
14).

On the other hand, in step S203 1. >1. When ,
Since the gain cannot be changed, data beyond the initial focusing operation cannot be obtained. Therefore, we decided to use data during focusing to determine camera shake. However, in order to not use this data when the focus lock switch Swo is on, step S21
In step 5, it is determined whether the focus lock switch Swo is on. The focus lock switch Swo is turned on when an attempt is made to take a picture with a composition in which the subject to be focused is placed outside the focus detection area. To explain its usage in detail, first, focus lock switch Sw. When the camera is off, the subject to be focused is captured within the focus detection area, and the subject is brought into focus by the focusing operation shown in FIG. In this state, the focus candle switch Swo is turned on to prohibit driving of the photographic lens, thereby maintaining the focused state of the subject, and changing the composition while maintaining the focused state. In this case, the focus lock switch SW. Since the object captured within the focus detection area is different before and after the focus lock switch Swo is turned on, the photodiode Ri~
Naturally, the information obtained from Rk and the information obtained after turning on will change. Therefore, since changes in this information are unrelated to camera shake, when the focus lock switch Swa is turned on, information from the automatic focusing operation is not used to determine camera shake.

If the focus lock switch Swo is off, the data from the first focusing operation is also used for camera shake detection, and steps 8203 to S207 are omitted and the process moves to step S208. When the focus lock switch Swo is on, it is considered that the composition has changed as described above, so the previous data cannot be used.

Therefore, the process moves to step S204 for re-detection. In step S215, focus lock switch SW. is on, in step S213 m,
and mt'k are compared, and when the focus lock switch Swa is off, m0 is compared in step 3213.
and m, are compared, and based on the difference, step S21
In step 4, camera shake is determined, and the series of camera shake detection routines is completed.

In the embodiment shown in Fig. 1 above, a signal based on the light flux from the center of the screen is generally used for camera shake detection as shown in Fig. 2, but rotational motion around the optical axis is also used to detect camera shake. Therefore, the configuration may be such that a signal corresponding to the periphery of the screen is used instead of the center of the screen. Further, the sensor is arranged so as to extend from the center of the screen toward the periphery at an angle to the edge of the screen frame, and a part of the photoelectric conversion element array near the periphery is used to detect camera shake. Good too.

Furthermore, the photoelectric conversion element rows may be composed of two sets of four orthogonal to each other, and if camera shake detection is performed using a portion of each of these four photoelectric conversion element rows, it is possible to detect the camera shake in any direction. It is also possible to detect camera shake phenomena. Furthermore,
The number of photoelectric conversion element arrays used may be configured to be changed depending on the subject brightness, subject distance, focal length of the photographic lens, and the like.

〔effect〕

As described above, according to the present invention, since a part of the photoelectric conversion element array for AP is used to detect camera shake,
The presence or absence of hand shake can be detected in a very short time, and the amplification degree of the amplifier can be increased compared to the AP detection, so the accuracy of hand shake detection can be improved. Therefore, there is an advantage that the response after camera shake detection can be carried out more quickly and reliably than in the conventional camera shake detection.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, and FIG. 2 is an optical system showing a schematic configuration of a detection optical system incorporated in a single-lens reflex camera to which the embodiment device of the present invention is applied. 3 is a flowchart of a series of photographing operations including camera shake detection in the embodiment of FIG. 1, FIG. 4 is a flowchart of automatic focusing operation in the embodiment of FIG. 2 is a flowchart of camera shake detection operation in the embodiment. [Explanation of symbols of main parts] l - - Photographing lenses 4, 5 - - Imaging lens 6 - - Release button Sw. ...One and a half press switch...One...
Buffer amplification!・・・・・Processing/control device・・・Brightness monitor・・・・・Gain controller

Claims (4)

[Claims] (1) In a camera with an automatic focusing device equipped with a charge-coupled device having a photoelectric conversion element array that photoelectrically converts light from a subject, an amplifier that voltage-amplifies transfer signals sequentially transferred from the charge-coupled device; and a subject. a brightness monitor having an overall detection means for detecting object brightness in the entire focus detection area during distance detection and a partial detection means for detecting part of the object brightness within the focus detection area during camera shake detection; a control means that inputs a transfer signal from the charge-coupled device and a detection signal from the brightness monitor, which are sequentially transferred, to control a charge accumulation time of the charge-coupled device and an amplification degree of the amplifier; and the brightness monitor. All transfer signals accumulated during the shorter of the charge accumulation time during subject distance detection and the charge accumulation time during camera shake detection determined based on the detection signal from the amplifier and transferred via the amplifier. A partial transfer signal corresponding to the luminance detection area of the partial detection means among them, and a brightness detection area of the partial detection means among all the transfer signals that are transferred again via the amplifier after a predetermined delay time. 1. A camera shake detection device comprising: comparison means for comparing the time-delayed transfer signal corresponding to the camera shake to determine the presence or absence of camera shake. (2) The amplifier compares the level range of the signal to be transferred to the control means with the dynamic range of the processing of the control means, and adjusts the gain amount via the gain controller so as to fully use the dynamic range. The camera shake detection device according to claim 1, wherein the camera shake detection device is configured to be controlled by. (3) The control means includes the comparison means, memory means for storing each of the transfer signals, and a timer for controlling the charge accumulation time of the charge-coupled device based on the detection signal from the brightness monitor. A camera shake detection device according to claim 1, characterized in that: (4) When the timer controls the charge-coupled device and the charge accumulation time during subject distance detection is smaller than the charge accumulation time during camera shake detection, the comparing means compares the partial transfer signal with the subject distance detection when the timer controls the charge-coupled device. 4. The camera shake detection device according to claim 3, wherein the camera shake detection device is configured to compare the time-delayed transfer signal after a predetermined delay time to determine the presence or absence of camera shake.