JPS60166911A - Shake detector of camera - Google Patents

Abstract

PURPOSE:To perform shake detection which uses an optical system and a processing system for a focus detector by carrying out focus detection and shake detection alternately after judging that an image formed through a photographic lens is in focus. CONSTITUTION:A processing sequence starts at the sensor image storage of a processor 11 and is carried out up to automatic focusing processing. An A-image signal A' which is one sequence before is stored in another memory area temporarily as a signal C. The signal C is regarded as a B-image signal at a stage of shake processing to calculate the phase difference (d) between two images A and B, and thus the difference between phases of the same image which are obtained at an interval of time is detected. Therefore, when the phase difference (d) is smaller than a specific permissible value, it is decided that there is no camera shake.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera shake detection device that detects shake using an optical system and a processing system for a focus detection device.

Traditionally, when detecting the focus of a camera's photographic lens,
A method for detecting the blur state of a subject image at a position conjugate to the film plane, and a method for detecting the blurred state of a subject image at a position conjugate to the film plane, and
Many methods are known, including methods for detecting phase differences in images.

Figures 1 to 3 show the principle of the conventional focus detection method using phase difference. Figure 1 shows the in-focus state, Figure 2 shows the front focus state, and Figure 3 shows the rear focus state. represents. As shown in FIGS. 1 to 3 (a), the photographing lens 1
An optical image formed by a light flux that has passed through two different regions is detected by two sensor arrays 3a and 3b via secondary imaging lenses 2a and 2b, and an output signal Sa is obtained, for example, as shown in (b). , obtain Sb. In the case of focusing shown in FIG. 1, two images are formed at substantially the same positions on the sensor arrays 3a and 3b, and the phase difference d between the two output signals Sa and Sb is approximately the same. However, when the front focus is in FIG. 2 and the rear focus is in FIG. The phase difference d is cl, c2
becomes. Therefore, the two obtained output signals Sa, Sb
By detecting the phase difference d, it is possible to detect the focal state of the photographic lens 1.

For example, the following algorithm is available for determining the phase difference d. That is, the two photoelectric conversion outputs Sa and Sb are respectively A images (a(1), a(2), ·φ·, a(n)) t
' B image (b(1), b(2), ..., b(n)) 0
Assuming 8 image signals, the correlation amount Pk of A image and B4'& is (
However, n=N-1k l, -N/2≦≦N/2)
It is defined as

According to formulas (1) and (1)', the correlation amount Pk is A image,
It calculates the consistency of the B image while changing the phase.
The k that minimizes the correlation amount Pk corresponds to the above-mentioned phase difference d. Therefore, if the phase difference d is calculated by calculating the equations (1) and (1)', the focal state of the photographic lens 1 can be determined.

Fig. 4 shows the signals of the A image and B image and the correlation amount Pk at that time. Fig. 4(c) is the image signal at the time of focusing, and the correlation amount Pk is α in Fig. 4(a). is shown. Similarly, in Figure 4 (
The correlation amount Pk corresponding to out-of-focus in b) is β in (a), the fourth
The correlation amount Pk corresponding to the out-of-focus state in FIG. 3(d) is indicated by γ in FIG. 3(a). The focus detection method using phase difference detection detects the phase difference between two images resulting from the light beams from two different areas of the photographing lens l.

Figure 5 shows images A (A, A') spaced apart in time. If there is no camera shake, the output signal will be almost the same as shown in Figure 5(a), but if camera shake occurs, the subject pattern imaged on the sensor will change due to the camera shake, so the output signal will be the same as shown in Figure 5(b). ), the waveforms differ considerably as shown in (c).

The purpose of the present invention is to utilize the phenomenon caused by two series of camera shakes,
The object of the present invention is to provide a camera shake detection device that detects camera shake using the optical system and processing system of the focus detection device and issues a warning.

The gist of the present invention to achieve this object is to provide an optical system that guides a part of the luminous flux of a photographic lens to a plurality of photoelectric conversion element groups;
a focus detection device that detects the focusing state of the photographic lens based on the output signals of the plurality of optical conversion element groups; and a blur detection device that detects a blur state using separate output signals, and the blur detection device is configured to operate when the focus detection device detects a focus state. This is a camera shake detection device.

The present invention will be explained in detail based on the embodiment shown in FIG. 6 and below.

In FIG. 6, reference numeral 11 denotes an image signal processing device comprising, for example, a one-chip microprocessor having a CPU (central processing unit), a memory circuit, input/output ports, and the like. A signal from a sensor device 12 consisting of sensor arrays 12a and 12b and a CCD (charge-coupled device) is input to this processing device 11 via an A/D converter 13.In addition, the control output of the processing device 11 , an electric motor 14 is operated.The sensor device 12 is operated by a CCD drive device 15, and a clock pulse signal is sent from a clock generator 16 to the CCD drive device 15 and the processing device 11. There is.

Here, two images are formed on the sensor arrays 12a and 12b by the light beams that have passed through different areas of the photographic lens, respectively.
Control signal φc from CCD drive equipment 1S, 5H1I
CG accumulates and transfers optical images. That is, when the start signal ST is applied to either the processing device 11 or the drive device 15, the drive device 15 sends out the accumulation start signal ICG to the sensor device 12 together with the clock φC generated by the 4g CI and K of the clock generator 16. The sensor device 12 starts accumulating two images from this point, and sends an accumulation completion signal EOI to the drive device 15 when a predetermined accumulation level is reached. Drive device 1
5 is the photoelectric conversion output transfer signal S! ( is sent to the sensor device 12 to transfer the charges accumulated in the sensor device 12 from the sensor section to the CCD section, and at the same time sends an end signal END to the processing device 11. Then, the clock φ from the drive device 15
In synchronization with A, the sensor device 12 time-sequentially outputs two images of analog photoelectric conversion signals O5 to the A/D converter 13.
/D converter 13 receives conversion command signal AD from drive device 15.
C and performs 8-bit A/D conversion, processing device 1
1, the digital time series signals DO to D7 are sent out. The processing device 11 inputs two image signals A (a(1), a(2)
), fist..., a(n)), B(b(1), b(2), -
--, b(1)) is temporarily stored in memory, and the phase difference d between the two images A and B is determined by the following procedure in order to perform automatic focusing processing.
Detect.

(I) C(i)・A(i) A(i)・a(1) B(i)・b(i) However, i=1.2. ..., N (■) Pk=b11 ” (' ” l kl )
−A (+) l (k < 0) = multi I B (
i)-A(i+k) I (k ≧ 0) + = square, n=N-1k l , -N/2≦≦N/2
(III) d=k l m1n(Pk) (-N/
(2≦≦N/2) Note that (III) means that d is the value of k that minimizes rPk. Then, by comparing the phase difference d and a predetermined autofocus tolerance value el (positive value),
If Idl≦e1, it is determined that the camera is in focus, and a high voltage level (hereinafter referred to as H) is applied to the display terminal JF, and the display terminal NF,
A low voltage level (hereinafter referred to as below) is output to the FF, and the LED 17 connected to the terminal JF is turned on. Also, d
<-el, it is determined that the front is in focus and outputs H only to the terminal IF, and if it is duel, it is determined that the rear pin is in focus, and the terminal FF is determined to be in focus.
Outputs H only to

In addition, when performing blur detection processing, use C (I) in operation (I).
By setting i) = A(i), in a series of processing sequences starting from sensor image accumulation, the A image signal A° before the l sequence is temporarily stored in a separate memory area as signal C, and the blur processing is performed. Then, use this as the B image signal,
If we calculate the phase difference d between the two images A and H, we will detect the phase difference between the same images separated in time, and if camera shake occurs, even though they are originally the same image. phase difference d
has a value that approximately corresponds to the amount of camera shake.

Therefore, the phase difference d at this time is the predetermined allowable value e for the amount of camera shake.
2 (net price), if Idl≦82, it is determined that no camera shake has occurred. This procedure is written as: (I') B(i) = C(i) (i=1.2. e ・@N) However, C(i) is transferred to another memory by the focusing process operation (I). This is the A image signal stored in the area one sequence before. (I), (n), and (III) are the same as in the focusing process, and (■°) can be added next to (I). Ru.

The terminals RN and FM of the processing device 11 are output terminals for driving the electric motor 14 connected to the photographic lens, and when both the terminals RN and FM are at H, the gates 18a and 18 are output.
Transistors 19a and 19c are off through b, 19b
, 19d are turned on, and electrical braking is applied to the motor 14 by transistors 19b, 19d and diodes 20a, 20b. When the terminal RM is H1 and the terminal M is L, the transistors 19a and 19d are off, and the transistors 19b and 1
9c is turned on, and the electric motor 14 is energized from right to left in the drawing. Further, when terminal PM is high and terminal FM is high, transistors 19b and 19c are turned off and transistors 19a and 19d are turned on, and the motor 14 is energized from left to right.
4, the terminal RM is driven in the opposite direction to that when the H1 terminal M is at the L level. When terminals RM and FM are both at L, transistors 19a to 19d are all turned off, and motor 14 is electrically released.

The terminal ERR of the processing device 11 becomes H when a camera shake is detected, and the camera shake warning light 21 is turned on.

The operation of the present invention with the above configuration will be explained with reference to the flowchart shown in FIG. The image signal processing device 11 includes a seventh
An algorithm based on the flowchart in the figure is preprogrammed. Note that [] represents a step number.

[The N-image signal processing device 11 issues a start signal ST, and the CC
The D drive device 15 sends a signal ICG to the sensor device 12 to start accumulating the optical image.

[21 After reaching a predetermined accumulation level, the sensor device 591
The drive device 15 receives the accumulation completion signal EOI from 2.
operates the A/D converter 13 to output the sensors 12a and 12.
The optical image conversion signal O8 of the optical image formed on image b is A/D converted, and the processing device 11 outputs two images A and B (7) digital signal a (
i), b(i) (+-1+2+...φN) and sequentially store them in the memory.

[3] To perform automatic focusing processing, according to the operation (■), calculate image signals ^(i), B(i) (i-1, 2, . . .
N) is generated. Here, the signal A(i) of one sequence before is stored as C(i) in another memory area for blur detection processing performed in the case of focusing.

[4] Calculate the phase difference d according to operations (II) and (III).

[5] Compare the phase difference d and the focusing tolerance e1.

[6] If 1dl≦81, it is determined that the focus is in focus, and the terminal JF is set to H.
Then, only the LED 17 connected to the terminal JF is turned on, and at the same time, the terminals RM and FM are set to H to apply braking to the electric motor 14.

[71] In the case of continued focusing, the A image signal C(i) of one sequence before stored in [3] is generated as B(i) according to the operation for detecting blur (■°).

[8] Similar to [4], calculate the phase difference d according to operations (■) and (IIl,).

[9] Compare the phase difference d and the focus signal value e2.

[10] If 1dl≦82, it is determined that there is no camera shake, L is output to the terminal ERR, and the LED 17 is turned off.

[11] If 1 d l > e2, it is determined that camera shake has occurred, outputs H to terminal ERR, and turns on warning light 2.
A warning is given to the user by lighting 1.

[12] In [5], if d<-el, front focus is determined, only terminal NF is set to H, and terminal RM is set to H1 end terminal M
The electric motor 14 is driven by setting the value L to L.

[13] If it is duel, it is determined that the focus is after, and only the terminal FF is set to H, then the terminal RM is set, and the terminal FM is set to H.
[Drive the electric fi 14 in the opposite direction to the case of 121.

In this way, in the embodiment, blur detection processing is performed when a focusing operation is determined, and after performing a series of operations, [1
], and the focus detection and blur detection are performed alternately.

Figures 8 and 9 show an example of a configuration in which the automatic exposure system program diagram is shifted to a high-speed shutter to prevent camera shake when the amount of camera shake from the camera shake detection signal is larger than a predetermined amount. There is. That is, FIG. 8 is, for example, JP-A-54-1.
This is an exposure control circuit having a known program function according to Japanese Patent No. 51445. Here, 30 is a circuit that outputs a so-called negative value of EV determined by subject brightness and film sensitivity as a voltage, and is comprised of a photometric circuit, a film sensitivity setting section, etc. (not shown). 31 is a circuit for providing the open aperture value AVo of the photographic lens, and 32 and 33 are known devices that control the aperture value and shutter speed based on the calculated AV value and TV value, respectively.

In the above-mentioned shake detection operation, program calculations when no camera shake is detected will first be explained. At this time, since the output of the output terminal a of the terminal ERR of the processing device 11 is L, the transistor 35 is turned off via the resistor 34. On the other hand, the transistor 36 is turned on by the resistor 37 and the inverter 38. Therefore, the resistance 39.40.4
1. By appropriately setting the operational amplifier 42, the constant voltages KVc, Vc, and the resistor 43 connected to the collector of the conducting transistor 36, the output of the operational amplifier 42 has AV' = (1/2). The calculated value of EV-1 is output. This output is analog switch 44
The open aperture value ^Vo from the circuit 31 is input to the terminal of an analog switch 45 paired with this switch 44.

The output A of the operational amplifier 42 is used for the comparator 46.
V' is connected to AVo of circuit 31, and AV'':
2 AVo (1) ,! :Kinari, AV'<A
Vo no! : Outputs H at times. The output of the comparator 46 is connected to the control terminals of the analog switch pair 44 and 45. When the output of the comparator 46 is L, the switch 44 is conductive and 45 is non-conductive. When the output is H, the switch 44 is non-conductive and the switch 45 is non-conductive. It becomes conductive. The output terminals of the switches 44 and 45 are connected to the output terminals, and the larger value between AV' and AVa is outputted as AV to the output terminals. That is, when the calculated AV' value is smaller than AVo, AV=AVo is set. Based on this AV value, the aperture value control device 32 appropriately controls the aperture.

The AV value is connected to the negative input of the operational amplifier 48 via the resistor 47, and the operational amplifier 48 and the resistor 47.49.50
, signal -EV, and constant voltage Vc, the operational amplifier 48 outputs TV=EV-AV. This TV causes the shutter speed control device 33 to control the movement of the rear curtain of the shutter.1. You will be in control.

Incidentally, the above-described series of operations represents the calculation of the program diagram of P shown by the solid line in FIG.

Next, when a camera shake is detected, the terminal a connected to the terminal ERR of the image signal processing device 11 becomes H by the aforementioned camera shake detection means, and unlike the case where there is no camera shake, the transistor 35 is turned on and the transistor 36 is turned off. , the resistor 51 connected to the collector of the transistor 35 becomes conductive. Then, depending on the resistance value of this resistor 51, AV"= (1/2)EV
A calculated value of -3 is output, and the following operations are the same as in the case without camera shake. In this case, the computation of the Q program diagram indicated by the broken line in FIG. 9 will be performed.

When camera shake is detected in this way, the program diagram shifts from P to Q in Figure 9, and a higher speed is selected with the same EV value, thereby reducing the effects of camera shake. becomes possible.

As explained above, the camera shake detection device according to the present invention is not only capable of detecting camera shake using the automatic focusing optical system and processing system, but also capable of detecting shake after focusing and focusing. By performing detection in chronological order, it is possible to detect the in-focus state, that is, the blur state immediately before shooting, and by virtually thinning out the focus detection after focusing, it is possible to prevent lens flickering in the in-focus state. can also be reduced.

[Brief explanation of drawings]

Figures 1 to 3 are principle diagrams of automatic focus detection, Figures 4 and 5
6 is a block circuit diagram of the processing system of the camera shake detection device according to the present invention, FIG. 7 is a flowchart thereof, and FIG. 8 is a block circuit diagram of the exposure control system. , FIG. 9 is a program diagram of the exposure control system. Reference numeral 1 is a photographing lens, 2a and 2b are secondary imaging lenses, and 3
a, 3b are sensor arrays, 11 is an image signal processing device, 12
1 is a sensor device, 13 is an A/D converter, 14 is an electric motor, 1
5 is a COD drive device, 32 is an aperture value control device, and 33 is a shutter speed control device. Patent applicant: Canon Co., Ltd. Figure 2 (G) (b) Figure 3 Figure 40 (O) (d) Figure 5 ((1) (b) (c) -

Claims (1)

[Claims] ・1. an optical system that guides a part of the luminous flux of the photographic lens to a plurality of photoelectric conversion element groups; a focus detection device that detects a focused state of the photographic lens based on output signals of the plurality of optical conversion element groups; a blur detection device that detects a blur state using temporally separated output signals of one or more of the optical conversion element groups, and the focus detection device detects a focus state. A camera shake detection device, characterized in that the camera shake detection device is configured to operate when a shake is detected. 2. Camera shake detection according to claim 1, wherein after the imaging state of the photographic lens is determined to be in focus by a focus detection device, focus detection and shake detection are performed alternately. Device. 3. A determination device that determines the magnitude of the amount of blur detected by the detection device relative to a predetermined level;
The camera shake detection device according to claim 1, wherein a warning is displayed when the amount of shake is larger than a predetermined level. 4. When controlling exposure using a predetermined shutter speed and aperture value according to a brightness level, a discrimination device is provided for determining the magnitude of the amount of blur detected by the blur detection device relative to a predetermined level. 2. The camera shake detection device according to claim 1, wherein the camera shake detection device has a camera shake detecting device and changes the predetermined shutter speed and aperture value when the amount of shake is larger than a predetermined level.