JP2002365521A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera, capable of measuring the speed of a moving subject at a low cost and automatically taking video which is free of blurs, based on the measured information. SOLUTION: This camera is equipped with an ultrasonic wave transmitting means (2) for radiating ultrasonic waves to the subject (5) at specified time intervals several times, a plurality of ultrasonic wave receiving means (3) for receiving the reflected ultrasonic wave from the subject and disposed separately from each other, a distance calculating means for calculating a distance between the respective ultrasonic wave receiving means and the subject from the received ultrasonic wave signal, and a speed calculation means for calculating movement information which includes the moving speed and the moving direction of the subject, from the calculated result on the distance to the subject, before and after the specified time has elapsed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for photographing a moving subject.

[0002]

2. Description of the Related Art A conventional camera has an AF (Auto Focus) function for measuring a distance to a subject and moving a photographing lens to obtain an in-focus image. With this function, if the subject is stationary, it is possible to obtain an in-focus image, but if the subject is moving, measure the distance to the subject and wait until the shutter is released. In this case, the distance to the subject changes, resulting in out-of-focus imaging.

As a technique for obtaining an in-focus image of such a moving subject, the distance to the subject is measured a plurality of times, and the moving speed of the subject is calculated from the distance measurement data. A technique is known in which the photographing lens is moved to a position corresponding to the calculated subject distance to perform photographing (Japanese Patent Laid-Open No. 5-1171). Further, as a technique for measuring the speed of a moving object, a technique using a radar type speed sensor or a microwave is known (Japanese Patent Application Laid-Open Nos. 8-180292 and 10-269492).

[0004]

By the way, the moving speed of the subject measured by the conventional technique is calculated by measuring the distance between the camera and the subject. Therefore, the moving speed of the subject only in the direction toward (or away from) the camera. It represents a speed component, not an absolute speed of a subject.

For this reason, when an image of a subject moving obliquely with respect to the camera is taken, the image may be blurred due to the influence of a speed component parallel to the camera.
In general, when the moving speed and moving direction of the subject are determined, it is possible to determine shooting conditions such as changing the shutter speed in advance so as to prevent such blurring, but the moving speed and moving direction of the subject are When it cannot be predicted and changes every time shooting is performed, it is difficult to perform such correction.

When photographing a moving subject, there is a case where it is necessary to know the moving speed. For example, if the athlete's running speed, vehicle speed, etc. can be grasped at the time of shooting, more accurate imaging will be possible, and if the speed is recorded corresponding to the imaging, the imaging will be impressed more strongly. It is thought that it becomes possible. However, for the above-mentioned reason, it was not possible to obtain the absolute speed of the subject with the conventional technology.

Further, when a radar type speed sensor or a microwave is used as the distance measuring sensor, the cost of the measuring device becomes large and the size of the measuring device becomes large. It is difficult to configure it for use.

The present invention has been made in view of the above circumstances, and can measure the speed of a moving subject at low cost, and can automatically shoot a blur-free image based on the information. The purpose is to provide a camera.

[0009]

In order to solve the above-mentioned problems, the present invention provides an ultrasonic wave transmitting means for irradiating an object with ultrasonic waves a plurality of times at predetermined time intervals, and receiving reflected ultrasonic waves from the object. A plurality of ultrasonic receiving means disposed apart from each other, distance calculating means for calculating the distance between each ultrasonic receiving means and the subject from the received ultrasonic signal,
The camera is provided with speed calculation means for calculating movement information including a moving speed and a moving direction of the subject from a result of calculating a distance to the subject before and after a predetermined time has elapsed.

According to the present invention, there is provided the camera according to the above-described invention, further comprising speed display means for displaying and outputting a measured speed value of the subject, and recording means for recording the measured speed value in correspondence with the photographed image of the subject. Camera.

According to the present invention, there is provided the camera according to the above-mentioned invention, wherein a predicting means for calculating a moving distance, a moving direction, and a separation distance from the subject after a lapse of a predetermined time from the moving distance, and a photographing mode from the prediction result A condition determining means for determining shooting conditions including an aperture and a shutter speed, a condition changing means for automatically changing the shooting conditions of the camera to the determined shooting conditions, and a condition display means for displaying and outputting the shooting conditions. It is a camera equipped with.

The present invention also provides a camera according to the above-mentioned invention, wherein a mode switching means for automatically switching to an auto-focus mode using ultrasonic waves when photographing in a passive auto-focus mode cannot function normally. It is a camera equipped.

Further, the present invention is the camera according to the above-described invention, further comprising irradiation angle changing means for changing the irradiation angle of the ultrasonic wave according to the zoom angle of the lens.

According to the present invention, in the camera according to the above-mentioned invention, the ultrasonic transmitting means is disposed at the center of the camera, and the ultrasonic receiving means is provided on both sides of the ultrasonic transmitting means at a predetermined distance from the ultrasonic transmitting means. It is a camera that is placed only apart.

According to the present invention, there is provided the camera according to the invention described above, wherein one of the plurality of ultrasonic receiving means is disposed near the ultrasonic transmitting means.

[0016]

FIG. 1 is a front view showing the structure of a camera according to the present invention.

In the first embodiment of the present invention shown in FIG. 1A, an ultrasonic transmitter 2 is arranged at the center of a camera 1,
In this configuration, one ultrasonic receiving unit 3 is arranged on each side. Hereinafter, the principle of measuring the speed of a moving object using the camera 1 having this configuration will be described.

FIG. 2 is a diagram for explaining the measurement principle of the present invention.

The ultrasonic waves emitted from the ultrasonic transmitting unit 2
Each ultrasonic receiving unit 3 reflected by the moving subject 5
Received at. Here, the position of the ultrasonic transmission unit 2 is indicated by a point A,
The position of the subject 5 is point B, the position of the ultrasonic receiver 3 is point C,
Let it be point D.

If the time from transmission of the ultrasonic wave to reception at the point C is T seconds, the distance L traveled by the ultrasonic wave during that time is expressed by the following equation (1), where V is the velocity of the ultrasonic wave.
It is represented by

L = V × T (1) This indicates that, at the point B, which is the position of the subject 5, the relation that the sum of the length between AB and BC is L is established. I have. That is, point B indicates that it is located on the locus of the first ellipse drawn with point A and point C as two focal points. This relationship also holds for points A, B, and D, and point B is also located on the locus of the second ellipse drawn with points A and D as two focal points.

The equations of these two ellipses can be expressed by a simple equation if the coordinate system is appropriately selected. Therefore, the position of point B can be analytically obtained by solving the equations as the intersection of the two ellipses. it can. Here, the distance between AC and A
By arranging the distances D so as to be equal, the coordinates of the point B can be obtained with a simpler logic with a reduced calculation error.

Therefore, by performing the same measurement again after a predetermined time, the coordinate position of the subject 5 after the lapse of the predetermined time can be obtained. Therefore, the moving speed and the moving direction of the subject 5 can be obtained using these results. Becomes possible.

In the second embodiment of the present invention shown in FIG. 1 (2), an ultrasonic transmitting unit 2 and an ultrasonic receiving unit 3 are arranged at one end of a camera 1, and an ultrasonic One receiving unit 3 is arranged and configured.

By arranging in this way, when calculating the coordinates of the point B, one of the curves becomes a circle.
The coordinates of point B can be calculated more easily, and A
Since the distance between C and AD can be increased, the coordinate position of point B can be calculated with higher accuracy.

It should be noted that the ultrasonic oscillator 2 and the ultrasonic receiver 3 at one end of the second embodiment can be shared by one ultrasonic sensor. In this configuration, the appearance of the camera can be simplified since only two ultrasonic sensors need to be arranged.

FIG. 3 is a flowchart showing a schematic image pickup operation of a moving subject.

When the photographer points the camera 1 at the subject 5 and presses the shutter (S1), in a half-pressed state, the ultrasonic transmitter 2 emits ultrasonic waves toward the subject 5 a plurality of times at predetermined time intervals. (S2). The ultrasonic receiver 3 measures the time until the irradiated ultrasonic wave is reflected by the subject 5 and received (S3).

FIG. 4 is a time chart showing a method of transmitting and receiving ultrasonic waves.

In (1) of FIG. 4, the ultrasonic transmitting unit 2 transmits ultrasonic waves at predetermined time intervals T, and the ultrasonic receiving unit 3 transmits these reflected ultrasonic waves to TA1 and TA1, respectively.
2, TB1 and TB2. Although the figure shows two transmissions, the present invention is not limited to this, and the transmission is performed a plurality of times and the appropriate data is adopted.

In this method, since the data for which the moving speed can be appropriately calculated is selected from the measured data and the calculation is performed, the measurement according to the speed of the subject 5 is possible, and the time is short. There is an advantage that the speed can be measured.
However, it is necessary that the ultrasonic transmitting unit 2 and the ultrasonic receiving unit 3 are not shared.

In (2) of FIG. 4, the ultrasonic transmitter 2 transmits an ultrasonic wave, and the ultrasonic receiver 3 receives these reflected ultrasonic waves after the passage of TA1 and TB1, respectively. Transmits ultrasonic waves again, and the ultrasonic wave receiving section 3 receives these reflected ultrasonic waves after the passage of TA2 and TB2, respectively.

In this method, the measurement can be performed without being affected by the speed of the subject, and the measurement can be performed after confirming the reception of the reflected ultrasonic wave, so that reliable measurement can be performed. Further, the present method can be applied even when the ultrasonic transmitting unit 2 and the ultrasonic receiving unit 3 are shared.

The transmitted ultrasonic waves do not need to be the same signal. For example, by changing the frequency of the ultrasonic wave transmitted first and the frequency of the ultrasonic wave transmitted subsequently, the transmitted signal is A configuration may be made so as to increase the certainty of the measurement by associating it with the received signal.

Subsequently, the moving speed, moving direction, coordinate position and the like of the subject 5 are calculated and obtained from the measured data in accordance with the procedure described in the measuring principle (S4). Then, a photographing condition of the subject 5 is obtained based on the result (S5).

First, the coordinate position of the subject 5 after a lapse of time from the present time until the shutter is fully pressed is predicted. This prediction can be obtained from the current coordinate position, the moving speed, and the moving direction of the subject 5. Subsequently, focus control of the camera is performed so that the predicted position of the subject 5 is focused. Then, a shutter speed that does not cause blurring is determined from the horizontal speed of the subject 5 and the distance to the subject 5.

Next, an aperture corresponding to the shutter speed is determined according to the brightness of the subject 5. The aperture value may be determined using, for example, a table set for each known photographing mode.

FIG. 5 is a diagram showing the relationship between aperture and shutter speed when shooting in the program mode.

According to this figure, if the shutter speed is determined for a certain Ev value (exposure value), for example, an appropriate aperture value can be obtained.

Subsequently, it is determined whether or not the shutter is fully pressed (S6).

When the shutter is fully pressed, the photographing condition of the camera 1 is changed to the calculated photographing condition, and photographing is performed (S7). Then, the measurement result such as the moving speed and the calculated photographing condition are associated with the photographed image and recorded (S
8). As a recording method, the captured image may be synthesized as character information, or may be recorded as information accompanying an image file according to a camera format called an EIXF format.

If the shutter remains half-pressed and does not change, the measurement result such as the moving speed and the calculated photographing condition are displayed on the display device attached to the camera 1 and presented to the photographer (S9). The photographer can know the speed of the subject from this information, and by presenting the photographing conditions, can be used as reference information when photographing regardless of the automatic photographing mode.

FIG. 6 is a view for explaining the operation of changing the irradiation angle of the ultrasonic wave according to the third embodiment of the present invention.

In FIG. 6A, the solid line indicates the case where the irradiation angle of the ultrasonic wave emitted from the ultrasonic wave transmitting unit 2 of the camera 1 is narrow (angle θ1), and the case where the irradiation angle is wide (angle θ).
2) is indicated by a dotted line.

If the speed of the subject 5 is high when the irradiation angle is small, the subject 5 may move during the measurement and move to the position of the subject 5a, and the speed may not be measured. Therefore, in this case, it is necessary to transmit an ultrasonic wave having a wide irradiation angle.

On the other hand, as shown in (2) of FIG. 6, when the irradiation angle is wide, the measurement becomes unstable due to the influence of other subjects 6, 7 other than the subjects 5, 5a to be photographed. Sometimes. Therefore, in this case, it is necessary to transmit ultrasonic waves having a narrow irradiation angle.

As a method of switching the irradiation angle of the ultrasonic wave, an output window provided with an opening on the front surface of the ultrasonic transmission unit 2 is provided, which is switched by using an array ultrasonic transmission element known in the art. Can be realized by using a technique such as switching back and forth or changing the size of the aperture.

The switching of the irradiation angle may be performed manually by the photographer, or may be performed in conjunction with the zoom angle of the lens. For example, if the lens is te
When the lens is on the le side or when the display of shooting is displaying tele, the irradiation angle is narrowed, and when the lens is on the wide side or when the display of shooting is displaying wide, the irradiation angle is widened. May be configured.

FIG. 7 is a flowchart showing a photographing operation according to the fourth embodiment of the present invention when the contrast of a subject is low.

When the shutter is half-pressed in the AF (auto focus) mode, the operation in the passive mode is started (S10).

First, a picked-up image is taken out from a shooting area, and a luminance signal of the image is extracted (S11).

Subsequently, a high-frequency component is extracted from the luminance signal, only the high-frequency component is integrated, and the value is recorded (S12). Then, the lens is moved by a predetermined amount (S13). The above operation is repeated until the lens moves by a predetermined range, and the movement position of the lens and the integrated amount of the high frequency component at that time are recorded (S14).

Next, the maximum value of the integral amount of the high frequency component is obtained from the recorded data (S16).

A curve is drawn with the lens movement amount on the X axis and the recorded data on the Y axis. If this curve forms a clear peak, it is determined that the necessary contrast has been obtained. The lens is moved to the peak position, that is, the position giving the maximum value (S17).

If the curve does not form a clear peak, it is determined that the necessary contrast has not been obtained, and the mode is switched to the active autofocus mode using ultrasonic waves to continue the focusing control. (S18).

With the above configuration, the moving subject 5 can be photographed by the automatic focus control even when the contrast is low.

[0057]

According to the present invention, the speed of a moving subject can be measured at low cost, and an image without blur can be automatically taken.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a camera according to the present invention.

FIG. 2 is a diagram illustrating a measurement principle of the present invention.

FIG. 3 is a flowchart showing a schematic imaging operation of a moving subject.

FIG. 4 is a time chart showing a method of transmitting and receiving ultrasonic waves.

FIG. 5 is a diagram illustrating a relationship between an aperture and a shutter speed when shooting in a program mode.

FIG. 6 is a diagram illustrating an operation of changing the irradiation angle of ultrasonic waves according to the present invention.

FIG. 7 is a flowchart showing a shooting operation when the contrast of the subject is low according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Camera 2 ... Ultrasonic transmission part 3 ... Ultrasonic reception part 5 ... Subject

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 9/08 G02B 7/11 N 2H102 13/36 D 2H103 17/18 F 17/24 G03B 3/00 A F-term (reference) 2H002 CC33 GA14 2H011 BA31 BA41 BB04 DA01 DA05 2H051 AA01 BA41 BB30 DA02 DA07 DA31 EB00 EB04 EB09 EB13 GA00 GA10 GA12 2H080 CC02 EE00 2H081 DD06 2H102 AA71 2H103 AA31 AA46

Claims (7)

[Claims] 1. A camera for photographing a moving subject, comprising: an ultrasonic transmitting means for irradiating the subject with ultrasonic waves a plurality of times at predetermined time intervals; and a distance receiving means for receiving reflected ultrasonic waves from the subject. A plurality of ultrasonic receiving means provided; distance calculating means for calculating a separation distance between the respective ultrasonic receiving means and the subject from a received ultrasonic signal; and a distance between the subject before and after the predetermined time has elapsed. A camera comprising: speed calculation means for calculating movement information including a movement speed and a movement direction of the subject from a calculation result. 2. The camera according to claim 1, further comprising: speed display means for displaying and outputting the speed measurement value of the subject; and recording means for recording the speed measurement value in correspondence with the photographed image of the subject. A camera characterized in that: 3. The camera according to claim 1, wherein a predicting unit that calculates a separation distance from the subject after a lapse of a predetermined time from a moving speed, a moving direction, and a separation distance of the subject, and from the prediction result. Condition determining means for determining shooting conditions including an aperture and a shutter speed in accordance with a shooting mode; condition changing means for automatically changing shooting conditions of the camera to the determined shooting conditions; and displaying and outputting the shooting conditions And a condition display means for performing the following. 4. The camera according to claim 3, further comprising a mode switching means for automatically switching to an autofocus mode using ultrasonic waves when photographing in a passive autofocus mode cannot function normally. A camera characterized by the following. 5. The camera according to claim 1, further comprising an irradiation angle changing means for changing an irradiation angle of the ultrasonic wave according to a zoom angle of the lens. . 6. The camera according to claim 1, wherein the ultrasonic transmitting means is disposed at a central portion of the camera, and ultrasonic receiving means are provided on both sides of the ultrasonic transmitting means by a predetermined distance from the ultrasonic transmitting means. A camera characterized by being spaced apart. 7. The camera according to claim 1, wherein one of the plurality of ultrasonic receiving units is an ultrasonic receiving unit.
A camera, wherein the camera is arranged near the ultrasonic wave transmitting means.