JP2003315862A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera whose release time lag is made small and which can accurately decide camera shake in spite of inexpensive and simple constitution. <P>SOLUTION: The camera is equipped with a 1st vibration detecting mode for detecting the vibration state of the camera by a 1st detecting method, and a 2nd vibration detecting mode for detecting the vibration state of the camera by a 2nd detecting method different from the 1st detecting method. Release switches 13a and 13b give a photographing instruction to the camera. A CPU 1 performs warning display by an LED 11 or the like when detecting the vibration of the camera. Then, the CPU 1 selectively switches the 1st vibration detecting mode and the 2nd vibration detecting mode according to whether the switches 13a and 13b are operated. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly, to a camera having a function of detecting camera shake generated during photographing and issuing a warning to a photographer.

[0002]

2. Description of the Related Art In general, when a photographer holds a camera with his / her hand and takes a picture, a camera shakes during exposure, resulting in a failure photograph, that is, a so-called camera shake may occur. In order to prevent this camera shake, various anti-vibration techniques have been studied. This anti-vibration technique is divided into two techniques: detection of vibration and countermeasures against the detected vibration.

Further, the technology for preventing camera shake is classified into a warning technology for making a user recognize a shaking state and a technology for preventing image deterioration due to camera shake by driving and controlling a photographing lens. Among them, as a warning technique, the present applicant has proposed, for example, in Japanese Patent Application No. 11-201845, a camera that suppresses a failure due to camera shake by devising a display means.

In addition, examples in which a distance measuring sensor is applied are also disclosed in Japanese Patent Laid-Open No. 2001-165622 and Japanese Patent Publication No. 62-2768.
No. 6, for example.

Usually, these warnings are made to be recognized by the photographer by lighting or blinking a display portion provided in the camera.

[0006]

However, in the shooting sequence of the camera, although it is an important requirement to shorten the time lag during the release operation, if the time is spent for calculation and detection for camera shake determination. The time lag will increase. If a large amount of data is used during camera shake detection, the detection accuracy will be improved, but in this case, calculation cannot be completed within a predetermined time unless a high-speed processing circuit is used, and such a high-speed circuit is costly. Moreover, it is not suitable for a low-priced camera in terms of power consumption.

On the other hand, in recent years, cameras such as digital cameras capable of erasing images and retaking images have been introduced, and detection after the start of photographing without the need to worry about the release time lag,
A technique has also been proposed that encourages the user to focus on the calculations and retake the picture if camera shake occurs.

The present invention has been made by paying attention to such a problem, and an object thereof is to perform an accurate camera shake determination with a low release time lag while having a low cost and a simple structure. To provide a camera that can.

[0009]

In order to achieve the above object, a camera according to a first aspect of the present invention includes a first vibration detection mode for detecting a vibration state of the camera by a first detection method, and the first vibration detection mode described above. A vibration detecting means having a second vibration detecting mode for detecting a vibration state of the camera by a second detecting method different from the first detecting method; an operation member for giving a photographing instruction to the camera; Warning means for giving a predetermined warning according to the detection result of the vibration detection means, and the first vibration detection mode and the second vibration detection mode are selectively switched depending on whether or not the operation member is operated. And a control means.

According to a second aspect of the invention, in the camera according to the first aspect, the first vibration detection mode uses a detection method that prioritizes the speed of detection, and the second vibration detection mode is A detection method that prioritizes the accuracy of detection is used, and the control means selects the first vibration detection mode before the operation member is operated, and after the operation member is operated, The second vibration detection mode is selected.

According to a third aspect of the present invention, in the camera according to the second aspect, the second vibration detecting means increases the number of detections or sets a predetermined value to be compared with the vibration detection result when issuing a warning. By changing it, the detection with priority given to accuracy is performed.

[0012]

1 is a block circuit diagram of a camera with a camera shake warning function to which the present invention is applied. In this configuration, the CPU 1 controlling the entire camera and the IFIC
2 and memory for storing adjustment data (EEPROM)
4, an autofocus (AF) unit 5a, and a photometry unit 5b
And an AF sensor 5c having a pair of light receiving lenses 5d and a pair of sensor arrays 5e, and a liquid crystal display element (LCD) 6 for displaying information relating to camera settings and shooting.
An in-viewfinder LCD 6a provided in the finder for displaying information related to shooting; a strobe unit 8 including an arc tube for emitting auxiliary light; and a main capacitor 8a for charging electric charges for causing the arc tube to emit light. A taking lens 9 having a zooming function, a warning display 11 including an LED, and a resistor 11 connected in series to the warning display 11.
a, release switches 13a and 13b for starting the shooting sequence of the camera, a mode switch 13c for setting the camera shake detection mode, a flash switch for changing the flashing state of the strobe of the camera, a shooting lens, A motor 18 that drives a drive mechanism such as the shutter 19 and film feeding, a rotary blade 16 that rotates in conjunction with the motor 18, and a hole of the rotary blade 16 that rotates for drive control of the motor 18 are optically formed. It is composed of a photo interrupter 17 for detection.

Here, the motor 18 may switch the driving destination by a switching mechanism when driving each driving mechanism such as the shutter 19 and the zoom lens barrel, or each driving mechanism is provided with a separate motor. Good.

In this structure, the CPU 1 controls the photographing sequence of the camera according to the operating states of the release switches 13a and 13b. That is, according to the output of the AF sensor 5c, in addition to the warning display by the in-view LCD 6a for camera shake warning, the AF unit 5a during photo shooting and the photometric circuit 5b for measuring the brightness of the subject for exposure control are driven to generate a necessary signal. Then, the motor 18 is controlled via the IFIC 2 described above.

At this time, the rotation of the motor 18 is caused by the rotation of the rotary blades 16.
The IFIC 2 waveform-shapes the signal output from the photo interrupter 17 according to the position of the presence or absence of the adjustment hole, and the CPU 1 monitors the rotation state of the motor 18. In addition, the strobe unit 8 emits auxiliary light as needed.

FIG. 2 shows a principle of distance measurement of the distance measuring sensor.
The distance between the principal points of the two light-receiving lenses 5d is called the baseline length B,
If the relative position difference x of the image 102 of the subject 101 formed on the pair of sensor arrays 5e through the two light receiving lenses 5d is obtained and the focal length f of the light receiving lens 5d is used,
The subject distance L is obtained from the relationship of L = B · f / x by the principle of triangulation. Here, the sensor array 5e is composed of a plurality of pixels and outputs an electric signal according to the brightness of the image to form an image signal.

FIG. 3 is a diagram for explaining an example of a warning pattern displayed on the LCD 6a in the finder. The in-finder LCD 6a is used for a screen display in the panorama mode, a blackout display indicating that the shutter is released, and the like.
It is also possible to use a as a display of a warning pattern.

The light-shielding pattern, which is a combination of the screen A and the screen C shown in FIG. 3, is a light-shielding pattern displayed when the panoramic photography is set, and is used. First, as shown in screen A, only the upper area is shielded from light, then, as shown in screen B, only the central area showing the shooting range at the time of panoramic shooting is shielded, and finally, as shown in screen C, the panorama light shield unit This is a pattern in which the light shielding of only the lower region of the above is sequentially and repeatedly performed. By repeating this display mode, the user looking into the viewfinder can recognize that the camera shake has occurred (if the patterns A, B, and C are shielded at the same time, the blackout display can be performed. ).

FIGS. 4 and 5 show the appearance of an example of the configuration of a camera having such a camera shake detection mode. Here, FIG. 4 shows the configuration viewed from the rear side of the camera, and FIG.
Shows the configuration seen from the front oblique direction. The details of the warning when a camera shake occurs will be described below with reference to these drawings.

Here, the aforementioned LCD 6a in the finder is used.
A warning method without using will be described. As shown in FIG. 4, a finder eyepiece portion 61 is provided on the back surface of the camera 10, and a light emitting diode (LED) 11 is provided beside it. When the camera shake occurs, the LED 11 is displayed blinking, and the user can recognize the warning even when the camera is held. When recognizing such a warning, the photographer can prevent camera shake by holding the camera 10 more firmly, for example, by attaching the left hand to the camera 10 held with one hand (right hand). . On the top surface of the camera 10, a mode display LCD 6 and a mode setting switch 1
3c, a release button 51, etc. are provided.

As shown in FIG. 5, a photographing lens 63 is provided on the front surface of the camera 10, a finder objective lens 64 and a light receiving lens of the photometric distance measuring unit 5 are provided above the photographing lens 63, and a strobe light emitting section 62 and LE for self-timer
D65 is arranged. If this LED 65 blinks when camera shake occurs, the user in front of the camera
It is possible to inform the photographer whether or not camera shake has occurred.

As shown in FIG. 5, on the front surface of the camera 10, there is provided a slidable barrier 10a for protecting the taking lens 63, the finder objective lens 64, and the light receiving lens of the photometric distance measuring unit 5 when being carried. Has been. The barrier 10a also serves as a power switch, and when the user opens the barrier 10a, the power of the camera is turned on,
When the retracted photographing lens 63 is extended to a predetermined position to enable photographing and the barrier 10a is to be closed, the photographing lens 63 is retracted into the camera and the power of the camera is turned off. ing.

The LED 11 provided in the vicinity of the viewfinder eyepiece lens 61 arranged on the back side of the above-mentioned camera is an LED for displaying the charging status of the existing strobe and the AF focusing display.
It may be combined with.

After the camera shake detection mode has been set, when the camera is held and the holding method is unstable and the camera shakes, the LCD 6 in the viewfinder as described above.
It is also possible to make a warning by blinking a, or, as shown in FIG. 4, blinking the LED 11 near the camera finder eyepiece 61.

Further, when such a shake occurs, as shown in FIG. 5, by providing a function of blinking the self-timer display LED 65 provided on the front surface of the camera, for example, the user of the camera can , It is possible to recognize the shaking state of the camera of the photographer who has requested for his / her own photographing.

A camera shake determination method based on the image output of the AF sensor 5c will be described with reference to FIGS.

When a camera having a pair of light receiving lenses 5d arranged side by side in the lateral direction of the camera (horizontal direction is the horizontal direction) is laterally shifted as shown in FIG. The monitor range 200 changes to 201, and the image data of the person 101 is in the horizontal direction (sensor arrangement direction) at the timing of t _{1 and} the timing of t ₂ as shown in FIG. 7A.
Shift to.

Further, when the camera is vertically shifted as shown in FIG. 6B, the monitoring range of the AF sensor 5c changes from 200 to 201, so that the part where the eye of the person 101 is being monitored is changed. A big change in the monitor position, that is, an image change, such as monitoring the mouth,
As shown in FIG. 8A, the shape of the image itself changes between the timing of t _{1 and} the timing of t ₂ .

Therefore, as shown in FIGS. 7B and 8B, it is possible to determine whether or not the monitor position has changed by obtaining the absolute value of the difference between the pixels. More specifically, the maximum change value of the absolute value of the difference in each pixel (MAX
By using (value) ΔI _MAX , it is possible to determine the change in the image signal, that is, the magnitude of camera shake.

However, if only this ΔI _MAX is used for the determination, the sensor data output from the same pixel changes greatly even when the camera shake is not so large by the lateral shift as shown in FIG. 7A. I will end up. In other words, even with the same amount of camera shake, in the camera shake determination method using only ΔI _MAX , the horizontal shift is determined to be larger than necessary and the vertical shift is determined to be small. To overcome this drawback, in the present invention, when a lateral shift ΔX exists, [Delta] I _MAX is not to use the determination, the use of [Delta] I _MAX only when the vertical direction of the shift is present, The size of the camera shake can be accurately determined by correctly grasping the magnitude relationship between the change in the image signal and the amount of camera shake.

FIG. 9A shows the relationship between the horizontal shake amount and the horizontal shift ΔX, and FIG. 9B shows the relationship between the vertical shake amount and the maximum change value ΔI _MAX. Shows.
The present embodiment uses such a relationship to perform highly reliable camera shake determination.

FIG. 10 is a flow chart for explaining the procedure of camera shake determination in the first vibration detection mode, which is performed prior to the release sequence. When the camera barrier (10a in FIG. 5) is opened, the switch detects this and branches from step S1 to step S2,
A determination flow for determining whether or not to display a warning is entered.

As described above, the predetermined time Δt ₁ (= t ₂ −t
_{After 1} ) (step S4), image detection is performed in steps S2 and S5. However, here, in order to increase the amount of information and detect camera shake by utilizing the portion of the largest image signal change (large contrast), steps S3 and S are performed.
At 6, the image signals I ₁ and I ₂ of the portion where the output difference between the adjacent sensors (pixels) is the largest are determined, and the lateral shift amount ΔX (see FIG. 7A) is detected at step S7. .

Next, it is judged whether or not ΔX is a predetermined value X ₀ or more (step S8). If YES, it is judged that the lateral shake is large, and step S8 is branched to step S12 to display a warning display. To do. The warning display method at this time is as described in FIG. 3 to FIG.

If the determination in step S8 is NO, that is, if lateral blurring is not detected, step S8 is branched to step S9 to confirm that ΔX is smaller than 1, and then the image signal I _1, detects the MAX value [Delta] I _{MA X} of the absolute value of the output difference of each pixel of I ₂ (step S
10). Next, it is determined whether this is larger than the predetermined value ΔI ₀ (step S11). The judgment here is YE
If S, that is, if the amount of change is large, step S11
To step S12, a warning is given and the process proceeds to step S13. If the determination in step S11 is NO, no warning is given and the process proceeds to step S13.

If the determination in step S9 is NO, the process immediately proceeds to step S13.

In step S13, it is determined whether or not the release switch has been operated. Unless the release switch is pressed, step S13 is branched to step S1 and the determination of the camera shake warning is repeated. If it is determined in step S13 that the release switch has been operated, the release sequence in step S14 is continued.

FIG. 11 is a flow chart for explaining the procedure of camera shake determination in the second vibration detection mode, which is performed after the release sequence. Step S21
Prior to the exposure (imaging for imaging), first, in step S20.
At, the warning flag is reset to 0. In this flag operation, the CPU operates 1 bit of the built-in RAM to store the state.

In step S22, the number of camera shake measurements is shown.
The variable n is initialized to 1. Image in the next step S23
Issue I_nIs detected and the above n (n = 1) and I_n(I_n
= I₁ ) And are recorded (step S24).

Next, it is judged whether or not the exposure is completed (step S25), and if the result is NO, the steps after step S40 are executed until the exposure is completed. First,
It is determined whether the warning flag is 0 (step S4).
0). Since the warning flag is reset to 0 in step S20, the determination here is YES. In the next step S41, the process waits for a predetermined time Δt _{2 and then} proceeds to step S4.
N is incremented by 2 and the detection of the image signal I _n is repeated in step S43.

Next, the image signal I _n detected at this time is compared with the first image signal I ₁ to judge whether the difference between them is large (step S44). If the difference is small, step S44. To NO, and n (n = 1) and the image signal I _n (I _n = I ₁ ) Is recorded (step S47).
At this time, prior to this recording, it is judged whether or not there is a large change from the previous image current (step S46), and when there is not much change from the previous image current, in order to save the memory (RAM) capacity of the CPU, The recording in S47 is not performed.

If it is determined in step S44 that I _n and I ₁ are significantly different, it is determined that the camera shake is too large and the warning flag is set to 1 (step S4).
5).

After steps S47 and S45, steps S25 and S40 (when the determination in S25 is NO) are executed. However, if the warning flag is set, it can be determined that the camera shake has already occurred. The determination in step S40 is NO, and the image determination after step S41 is not performed. This can save the RAM capacity.

In this way, based on the change data (relationship between n and I _n ) of the image signal obtained during image pickup and the warning flag, the warning flag is set to 1 after the exposure is judged to have ended in step S26. It is determined whether or not (step S27), YES
If branches the warning step of step S30, when the flag is not 1, performs shake determination based on the relationship of the resulting n and I _n in step S24, S47 (step S28). Then, it is determined whether or not a warning is necessary (step S29), and when it is determined that the warning is necessary, the step S29 is branched to the step S30 to issue the warning.

FIG. 12 schematically shows the relationship between the number of times of measurement n thus obtained and the image data.
The image data actually consists of a plurality of sensor data, but here, one point is shown. The pitch Δt ₂ of the measurement time here is made finer than the pitch Δt ₁ used in the determination before release in FIG.

Generally, the cycle of camera shake is said to be about 5 to 10 Hz, and Δt ₁ is correspondingly about 100 msec. However, Δt ₂ is for accurately investigating the locus of image change occurring in a short time. The pitch is set to ⅕ of Δt ₁ . With such fine detection, it is possible to reliably detect even a large change in the amplitude of the image signal immediately after the release is pressed (n = 2 to n = 4 in FIG. 12).

On the other hand, in the detection at the interval of Δt ₁ before the release shown in FIG. 10, a simple detection method which does not detect such an amplitude is adopted. This is because the holding state of the camera is checked, and therefore the determination process is simplified in order to detect whether or not the camera is moving.

With such a method, ΔI ₂ cannot be detected, and the difference between the detection results is ΔI ₁ . However, after the release, more accurate check is necessary because the picture is actually blurred. In this case, if you do not retake the picture immediately, you will miss the opportunity. However, the real-time warning as before the release is not necessary, and the determination may be made in consideration of the situation during shooting.

As described above, in this embodiment, before the release, the simplified determination as shown in FIG. 10 is performed to prioritize the speed of detection, but in the determination after the release, the detection as shown in FIG. 13 is performed. The camera shake is determined with priority given to the accuracy of.

That is, first, in step S50, the actual exposure time t _EXP is determined, and in the next step S51, the determination values σ ₀ and ΔI ₀ are calculated in consideration of the exposure time t _EXP and the focal length of the photographing lens. Then, the calculation and determination after step S52 are performed.

That is, in step S52, the average value of the image data when the graph shown in FIG. 14 is obtained is calculated, and this is set as I _AVE . In step S53, the variation of each measurement data is obtained in the form of standard deviation σ.

Next, it is judged whether or not the σ obtained at this time is larger than the above-mentioned σ ₀ (step S54), and if it is larger, it is judged that the variation of the image data is large, and from step S54 to step S61. Branch and give a warning.
If σ is determined to be small in the determination in step S54, the process branches from step S54 to step S55, and the period t during which the image data output a substantially average value is t.
_AVE (see FIG. 14) is calculated, and it is determined whether this is approximately the same as the exposure time t _EXP (step S56). If the determination here is NO, it is assumed that the camera shake is such that the change in the image signal is large during the predetermined exposure time and affects the appearance of the photograph, and the process branches to step S61 to issue a warning. To do.

If the determination in step S56 is YES, MAX / MIN of the image data is calculated in step S57,
58, and the difference ΔI ₂ (see FIG. 12) is calculated in step S59. Then, it is judged whether or not the calculated ΔI ₂ exceeds a predetermined value ΔI ₀ (step S6
0), if YES, this flow ends, but if NO, branch to step S61 to issue a warning.

The ΔI ₀ and σ _{0 which} is the reference for the determination in step S54 can be changed depending on the focal length and the exposure time at the time of photographing.

In this way, in the camera shake determination after the release,
The camera shake is determined by considering parameters that were not taken into consideration before the release, and more accurate not only by considering the difference between two image data detections but also by the results of multiple data acquisitions. Since the camera shake is judged and it is displayed whether or not the actual shooting result is due to the camera shake, you can immediately retake the picture when you unintentionally press the release button and take a failed picture. We can provide a camera.

Further, steps S101 to S101 of FIG.
As in S108, the warning display method may be changed before and after shooting. In other words, before shooting, it is necessary to call attention to the user holding the camera in order to reduce camera shake, and the warning on the LED (11 in Fig. 4) near the viewfinder is effective. Since the user is not holding the camera since the shooting is performed, another display method is preferable in order to reduce the annoyance when the LED blinks.

For example, as shown in FIGS. 15 (b) and 15 (c), the camera shake mark on the LED for displaying the number of frames may be blinked so that only the user concerned can check it. This camera shake mark can be easily realized without adding a large segment on the LCD if it also serves as a display when the camera shake prevention mode is set.

Further, if the data used for the determination is simply increased, a time lag of the processing time will have an influence, but in this way, before and after the release, a high speed but rough detection and a time-consuming but accurate measurement are performed. Since the determination method is switched to highly accurate detection, it is possible to effectively use the processing circuit that keeps the energy consumption as low as possible while maintaining the standard shooting speed as a whole.

Further, even when the image signal changes greatly, if it is limited to a slight period within the exposure time, no warning is given because it does not affect the appearance of the photograph.

Further, in order to make a more accurate judgment, the time interval (pitch) for judging the image change is narrowed, and the problem of lack of memory (RAM) due to handling a large amount of data is We have solved it by not storing the same data as the last time, and by not acquiring more data when camera shake is too large.

[0061]

As described above, according to the present invention,
It is possible to provide a camera that has a low release time lag and that can perform accurate camera shake determination at low cost and low current consumption.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a camera with a camera shake warning function to which the present invention is applied.

FIG. 2 is a diagram showing a principle of distance measurement of a distance measurement sensor.

FIG. 3 is a diagram for explaining an example of a warning pattern displayed on an in-finder LCD 6a.

FIG. 4 is a diagram (No. 1) illustrating an appearance of a configuration example of a camera having a camera shake detection mode.

FIG. 5 is a diagram (No. 2) showing an appearance of a configuration example of a camera having a camera shake detection mode.

FIG. 6A is a diagram showing a state when the camera is horizontally shifted, and FIG. 6B is a diagram showing a state when the camera is vertically shifted.

FIG. 7A shows a state in which the image data shifts when the camera is laterally shifted, and FIG. 7B shows a method for determining whether or not the monitor position has changed. Is.

FIG. 8A shows how the image shape changes when the camera is vertically shifted, and FIG. 8B illustrates a method for determining whether or not the monitor position has changed. It is a figure.

9A is a horizontal blur amount and a horizontal shift Δ. FIG.
FIG. 3B shows the relationship between X and (b), which shows the relationship between the vertical blurring amount and the maximum change value ΔI _MAX .

FIG. 10 is performed prior to a release sequence,
6 is a flowchart for explaining a procedure of camera shake determination in the first vibration detection mode.

FIG. 11 shows a second process performed after the release sequence.
6 is a flowchart for explaining a procedure of camera shake determination in the vibration detection mode of FIG.

FIG. 12 is a diagram schematically showing the relationship between the number of measurements n and image data.

FIG. 13 is a flowchart showing the procedure of camera shake determination processing for calculating the determination values σ ₀ and ΔI ₀ in consideration of the actual exposure time t _EXP and the taking lens focal length.

FIG. 14 is a diagram for explaining the calculation of the image data average value executed in step S52 of FIG.

FIG. 15 is a diagram for explaining a method of changing the warning display method before and after shooting.

[Explanation of symbols] 1 CPU 2 IFIC 4 memory (EEPROM) 5a Autofocus (AF) section 5b Metering unit 5c AF sensor 5d 1 pair of light receiving lens 5e 1 pair of sensor arrays 6 Liquid crystal display (LCD) 6a LCD in viewfinder 8 Strobe circuit 8a Main capacitor 9 Shooting lens 11 Warning display 11a resistance 13a, 13b Release switch 13c Mode selector switch 16 rotating blades 17 Photointerrupter 18 motor 19 shutters

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Suzuki             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F term (reference) 2H102 AB08 BB05

Claims (3)

[Claims] 1. A first vibration detection mode for detecting a vibration state of a camera by a first detection method and a second vibration detection mode for detecting a vibration state of a camera by a second detection method different from the first detection method. A vibration detection mode, an operation member for instructing the camera to take a picture, a warning unit for issuing a predetermined warning according to the detection result of the vibration detection unit, and the operation member being operated. First, depending on whether or not
And a control means for selectively switching between the vibration detection mode of 1. and the second vibration detection mode. 2. The first vibration detection mode uses a detection method that prioritizes detection speed, and the second vibration detection mode uses a detection method that prioritizes detection accuracy. The control means selects the first vibration detection mode before the operation member is operated, and selects the second vibration detection mode after the operation member is operated. The camera according to claim 1. 3. The second vibration detecting means performs detection with priority on accuracy by increasing the number of times of detection or changing a predetermined value to be compared with a vibration detection result when issuing a warning. The camera according to claim 2.