JPS60166910A - Shake detector of camera - Google Patents

Abstract

PURPOSE:To perform shake detection which utilizes an automatic focusing optical system and a processing system by detecting a shake state by using signals generated at intervals of time through a photoelectric converting element which photodetects part of luminous flux from a photographic lens. CONSTITUTION:Two images A and B are formed on sensor arrays 12a and 12b with pieces of luminous flux passed through different areas of the photographic lens, and the light images are stored and transferred with the control signal from a CCD driving device 15. The phase difference (d) between the two images A and B is detected and compared with an automatic focusing permissible value for automatic focusing processing, and it is decided that the images are in focus when the phase difference is smaller. When shake detection processing is performed, an A-image signal A' which is one sequence before is regarded as a B- image signal and the phase difference (d) between the two image storage. Thus, the difference between phases of the same image which are obtained at an interval of time is detected to decide that there is no camera shake when the phase difference (d) is smaller than a specific permissible value.

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 blurring of a subject image at a position conjugate to the film surface, and a method for detecting blurring of a subject image at a position conjugate to the film surface,
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 as shown in FIG. 1, two images are formed at approximately 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 zero. However, when the front focus is in FIG. 2 and the rear focus is in FIG. The phase difference d is d=cl, c
It becomes 2. Therefore, the obtained two output signals Sa, Sb
The focal state of the photographic lens 1 is detected by detecting the phase difference d. 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
・Fist, a(n)), B image (b(1), b(2), ・
..., b(n))08 image signals, and the correlation amount Pk of image A and image B is Pk=,;, 1b(i+l k 1)-a
(iN (k<O) (1) ' = (where n=N
−l k l , −N/2≦ and ≦N/2).

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 images A and B 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 lens 1 photographed in this manner.

FIG. 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).

An object of the present invention is to detect camera shake using the optical system Φ processing system of a focus detection device by utilizing the above-mentioned phenomenon caused by camera shake,
An object of the present invention is to provide a camera shake detection device that gives a warning.

The gist of the present invention for achieving this object is characterized in that it is configured to detect a blur state using temporally separated output signals of a photoelectric conversion element that receives a part of the light flux of a photographic lens. 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 consisting of, for example, an 1-chip microprocessor having a CPU (central processing unit), a memory circuit, input/output ports, and the like. This processing device 11 receives signals from a sensor device 12 consisting of sensor arrays 12a and 12b and a CCD (charge coupled device).
It is input via a converter 13. Further, the electric motor 14 is operated by the control output of the processing device 11. The sensor device 12 is operated by a CCD drive device 15, and a clock pulse signal is sent to the CCD drive device 15 and the processing device 11 from a clock generator 16.

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 signals φc, SH, I from the CCD drive device 15
CG accumulates and transfers optical images. That is, when the processing device 11 gives the start signal ST to the drive device 15, the drive device 15 sends the P7 product start signal 11J to the sensor device 12 together with the clock φC generated by the signal CLK 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 15
sends the photoelectric conversion output transfer signal SH to the sensor device 12, and transfers the charge accumulated in the sensor device 12 from the sensor section to C.
Transfer to the CD section, and at the same time send an end signal EN to the processing device 11.
Send D. Subsequently, in synchronization with the clock φC of the drive device 15, the sensor device 12 outputs two images of analog photoelectric conversion signals O8 in time series to the A/D converter 13, and the A/D
The converter 13 performs 8-bit A/D conversion in synchronization with the conversion command signal ADC from the drive unit @15, and sends the digital time series signal DO-07 to the processing device 11. The processing device ll receives input two-image signals A (a(1), a(2),
..., a(n)), B (b(1), b(2)
, ..., b(n)) are temporarily stored in the memory, and the phase difference d between the two images A and B is detected by the following procedure in order to perform automatic focusing processing.

(I) A(i)=a(i) B(i)=b(i) (isl, 2. ..., N) (■) P k = btl B (+ ” l k I
) −A (s) l (k < O)=Σl B
(i)-A(i+k) l (k≧O)n However, n=N-l k 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. And the phase difference d
By comparing the predetermined autofocus tolerance value el (positive value),
If l≦el, it is determined that the focus is on, and a high voltage level (hereinafter referred to as H) is applied to the display terminal JF, and the display terminals NF and FF are
outputs a low voltage level (hereinafter referred to as below) to terminal JF.
Turn on the LED l 7 connected to. Also, d<
If -el, it is determined that the front is in focus and outputs H only to the terminal NF; if d>el, it is determined that the rear is in focus and H is output only to the terminal FF.

Further, when performing blur detection processing, in a series of processing sequences starting from sensor image accumulation, the A image signal A' of one sequence before is used as the B image signal.

By calculating the phase difference d between the two images A and H, it is possible to detect the phase difference between the same images that are separated in time. Phase difference d
has a value that roughly corresponds to the camera shake.

Therefore, the phase difference d at this time is the predetermined allowable value e for the amount of camera shake.
2 (positive value), if Idl≦82, it is determined that no camera shake has occurred. This procedure is written as: (I') A(i) = a(i) B(i) = A' (i) (i=1.2..., N) However, A' (i) is A stored one sequence ago
It is an image signal, and (11) and (lit) are the same as in the focusing process.

The terminals RN and FM of the processing device 11 are output terminals for driving the electric motor 14 connected to the photographing lens, and when both the terminals RN and F'M 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 the terminal PM is high and the terminal FM is high, the transistors 19b and 19c are turned off, and the transistor 19a is turned off.

19d is turned on, the electric motor 14 is energized from left to right, and the electric motor 14 is driven in the opposite direction to when the terminal RM is at the H1 terminal and the terminal M is at the L level. And terminals RM, F
When both M are L, transistors 19a-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. Further, the switch 22 is an AF lock switch, and if the camera user turns it on when he or she wants to stop the automatic focusing function, the processing device 11 accepts this and connects the terminal RM to the AF lock switch.
The FM is set to H and the electric R14 is stopped.

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 ff1l includes
An algorithm based on the flowchart of FIG. 7 is preprogrammed. Note that [ ko represents the step number.

[1] Emit a start signal ST from the image signal processing device 11, and
The CD drive device 15 sends a signal ICG to the sensor device 12 to start accumulating optical images.

[21 After reaching a predetermined accumulation level, the sensor device 12
The drive device 15, which has received the accumulation completion signal EOI from
The optical image conversion signal O5 of the optical image formed above is A/D converted, and the processing device 11 receives two images A, B (7) digital signal a(i
), b(i) (i=1.2.=,N) and sequentially store them in memory.

[3] The processing device 11 checks the AF lock switch 22 here.

[4] If the AF lock switch 22 is off, image signals A(i), B(i) for automatic focusing (i=1.2°・..., N
) is generated.

[5] Calculate the phase difference d according to operations (n) and (1).

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

[7] 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.

[81d<-el, it is determined that the front is in focus, only the terminal NF is set to H, and furthermore, the terminal RM is set to H1 and the terminal M is set to L to drive the motor 14.

[9] If d>el, it is judged as rear focus and only terminal FF is used! (Furthermore, the terminal RM is set to L and the terminal FM is set to H, and the electric motor 14 is driven in the opposite direction to that in case 81.

Ru.

[10] When the AF lock switch 22 is on, terminals JF and NF are all set to L in order to lock the autofocus, the autofocus LED 17 is turned off, and the terminals RM and NF are turned off.
Braking is applied to the electric motor 14 by setting FM to H.

[111 Image signals for blur detection A(i), B(i) (i=1.2..., according to operation (I') for blur detection processing)
N) is generated.

[12] Similar to [5], operation (II), (n[)
The phase difference d is calculated according to 6 (t4J) If Idl≦e2, it is determined that there is no camera shake, L is output to the terminal ERR, and the LED 17 is turned off.

[15] If 1dl>e2, it is determined that camera shake has occurred, and a warning is given to the user by outputting H to the terminal ERR and lighting the warning light 21.

In this example, since it is difficult to perform blur detection during automatic focusing due to the movement of the subject image,
As described above, after automatic focusing, the AF lock switch 22 is turned on to detect blur. Also, after performing the above series of operations, the process returns to the start of sensor accumulation in [1], but at this time the two image signals A(i), B(i) (i=1, 2..
. . , N) are held in the memory up to [4] or [11].

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 described. At this time, since the output terminal a of the terminal ERR of the processing device 11 is being output, 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 and Vc, and the resistor 43 connected to the collector of the conductive transistor 36, the output of the operational amplifier 42 has AV' = (1/2) EV. The calculated value of -1 is output. This output is connected to one terminal of an analog switch 44, and the open aperture value AVo from the circuit 31 is input to the terminal of an analog switch 45 paired with this switch 44.

The output of the operational amplifier 42 is A for the two-man power of the comparator 46.
V' and AVO of circuit 31 are connected.

AV' ≧AVo c7) Tokinari, AV'
<AVO(7),! l: 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 when the output is H, the switch 44 is non-conductive. 45 is conductive. The output terminals of the switches 44 and 45 are connected to each other, and the larger value of AV' and AVo is outputted as AV to the output terminals. That is, the calculated AV' value is AV
If it is smaller than o, 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.

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 above-mentioned 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. Resistor 51 connected to the collector of transistor 35 becomes conductive. Then, depending on the resistance value of this resistor 51, "rAV' = (1/2)
EV-3cy) The calculated value 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 faster shutter speed is selected with the same EV value, making it possible to reduce the effects of camera shake. Become.

As explained above, the camera shake detection device according to the present invention is not only capable of detecting camera shake using the autofocus optical system and processing system, but also capable of automatically focusing after the autofocus lock operation. By using a sequence that performs focus processing, it is possible to detect the blur state immediately before actual photographing, and it is possible to issue a warning or perform a program shift depending on the amount of blur.

[Brief explanation of drawings]

Figures 1 to 3 are principle diagrams of automatic focus detection, Figures 4 and 5
The figure shows the principle of shake detection, Figure 6 is a block circuit configuration diagram of the processing system of the camera shake detection device according to the present invention, Figure 7 is a flowchart thereof, and Figure 8 is the block circuit configuration of the exposure control system. 9 are program diagrams 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, 22 is an AF lock switch, 32
33 is an aperture value control device and a shutter speed control device. Patent applicant Canon Co., Ltd. Drawings Figure 1 (a) (b) Figure 2 ((]) (b) Figure 3 (CI) (b) (d) Figure 5) (b) (c) Part 7 figure

Claims (1)

[Claims] 1. Camera shake detection, characterized in that it is configured to detect a shake state using temporally separated output signals of a photoelectric conversion element that receives a part of the luminous flux of a photographic lens. Device. 2. The camera according to claim 1, wherein the detection of the blur is performed using a focus detection device that detects the in-focus state of the photographic lens based on the output signal of the photoelectric conversion element. Shake detection device. 3. A patent claim, further comprising a blocking switch means for blocking the operation of the lens drive control device that operates according to the focus detection device, and in response to the operation of the blocking switch, the detection device for detecting the blur state is operated. The camera shake detection device according to item 1. 4. A discriminating device for discriminating the dog-likeness of the amount of blur detected by the detecting device based on a predetermined level;
142. The camera shake detection device according to claim 141, wherein a warning is displayed when the amount of shake is larger than a predetermined level. 5,! In the case of controlling fog output using a predetermined shutter speed and aperture value according to the 1I11 degree level,
a determination device that determines the magnitude of the amount of blur detected by the blur detection device relative to a predetermined level;
The camera shake detection device according to claim 1, wherein the predetermined shutter speed and aperture value are changed when the blur is larger than a predetermined level.