JP6320094B2 - Imaging apparatus, control method thereof, and program - Google Patents

Description

  The present invention relates to an imaging apparatus having a function of calculating an azimuth, a control method thereof, a program, and a computer-readable storage medium.

In recent years, there has been an increasing need to know the shooting position and shooting direction in digital cameras. An electronic compass using a geomagnetic sensor and an acceleration sensor is incorporated in the digital camera, and the shooting direction is calculated and stored in association with the shot image. The function is put into practical use.
However, since the electronic compass detects the geomagnetism and calculates the azimuth, if there is something that affects the magnetic field inside the digital camera, the calculation accuracy of the azimuth deteriorates in principle.
Conventionally, a method for avoiding this problem has been proposed. For example, in Patent Document 1, an operation period of a magnetic field generating component that affects the geomagnetic sensor is determined, and based on the value of the geomagnetic sensor in a period other than the operation period. A method for calculating an imaging orientation is disclosed. Further, Patent Document 2 discloses a method in which an electric drive unit that affects a geomagnetic sensor is controlled so as to be in a non-driven state after a shutter operation, and a direction is calculated by taking in the output of the geomagnetic sensor during this time. .

JP 2011-139375 A JP 2012-90124 A

However, there are various factors in the digital camera that affect the electronic compass, and these operate in a complicated manner during shooting. When operating in conjunction with an external device such as a lens or a strobe like a digital single-lens reflex camera, it is necessary to consider the influence from the external device.
In the prior art disclosed in the above-mentioned patent documents, the timing for operating the electronic compass is limited, and the shooting direction cannot always be calculated. For this reason, there is a limit to the timing at which a shooting orientation suitable for use can be calculated. As a result, there is a possibility that the shooting direction cannot be used or inappropriate direction information is used.

  The present invention has been made in view of the above points, and an object of the present invention is to be able to accurately calculate the azimuth so that the timing for calculating the azimuth is not limited.

The imaging apparatus according to the present invention includes an imaging unit, a power source, a geomagnetism detection unit, an angular velocity detection unit, and the geomagnetism detection unit under a certain condition in a state where power is supplied from the power source to the imaging unit. A control means for switching between a method for calculating the azimuth using the method and a method for calculating the azimuth using the angular velocity detection means, and a current detection means for detecting a current supplied from the power source to the imaging means, When the current is constant, the control means adopts a method of calculating the azimuth using the geomagnetic detection means, and when the current is not constant, adopts a method of calculating the azimuth using the angular velocity detection means. It controls to do.

  According to the present invention, the azimuth can be calculated with high accuracy so that the timing for calculating the azimuth is not limited.

It is a block diagram which shows the structure of the digital single-lens reflex camera which concerns on embodiment. It is a figure for demonstrating the calculation principle of the imaging | photography direction using a geomagnetic sensor. It is a figure showing on the time-axis the imaging | photography sequence of a digital single-lens reflex camera. It is a figure which shows an example of the external appearance of the digital single-lens reflex camera which concerns on embodiment. It is a figure which shows the switching timing of the geomagnetic sensor and gyro sensor in 1st Embodiment. It is a figure for demonstrating the calculation principle of the imaging | photography azimuth | direction using a gyro sensor. It is a figure showing on the time-axis the imaging | photography sequence of a digital single-lens reflex camera. It is a figure which shows the switching timing of the geomagnetic sensor and gyro sensor in 2nd Embodiment. It is a figure which shows the example of a display which prompts the calibration of a geomagnetic sensor.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a block diagram illustrating a configuration of a digital single-lens reflex camera according to the embodiment.
Reference numeral 100 denotes a lens that can be attached to and detached from the camera body, 101 denotes AF, and 102 denotes an aperture. Reference numeral 103 denotes an image sensor, 104 denotes a mechanical shutter, and 105 denotes a mirror. Reference numeral 106 denotes a switch, 107 a power supply circuit, 108 a battery, 109 a communication interface, 110 a recording device, 111 a display device, and 112 a strobe. Reference numeral 113 denotes a microcomputer. 114 is an acceleration sensor, 115 is a gyro sensor (angular velocity sensor) which is an angular velocity detecting means, and 116 is a geomagnetic sensor which is a geomagnetic detecting means. 117 is a current detection circuit, and 118 is a motion detection circuit. The current detection circuit 117 is used in the first embodiment, and the motion detection circuit 118 is used in the second embodiment, but both blocks are shown here for convenience.

  The shooting operation is started when the user operates the switch 106. In the photographing operation, the microcomputer 113 performs the AF / AE operation and drives the lens 100. When the AF / AE operation is completed, the diaphragm 102 and the mirror 105 are driven according to the photometric value, and then the mechanical shutter 104 starts to travel. The imaging sensor 103 is driven almost simultaneously with the traveling of the mechanical shutter 104 to photograph the subject. In the AE operation, when it is determined that the subject is dark, charging control of the strobe 112 is performed, and light emission control of the strobe 112 is performed at the timing when the image sensor 103 is driven.

  Here, the microcomputer 113 basically calculates the shooting direction using the geomagnetic sensor 116 and the acceleration sensor 114. As will be described in detail below, the microcomputer 113 replaces the geomagnetic sensor 116 under certain conditions. Switching to a method of calculating the shooting direction using the sensor 115.

  The current detection circuit 117 detects an operating current of a predetermined block. The predetermined block is a block that affects the geomagnetic sensor 116, and the current detection circuit 117 may be provided corresponding to a plurality of blocks, not just one block. In the present embodiment, the current detection circuit 117 includes a driving current for the lens 100, a driving current for the diaphragm 102, a driving current for the mechanical shutter 104, a driving current for the mirror 105, a driving current for the image sensor 103, a charging current for the strobe 112, and a strobe. The light emission current 112 and the drive current of the display device 111 are detected.

  The microcomputer 113 monitors the output of the current detection circuit 117 while calculating the shooting direction. When the output of the current detection circuit 117 is less than a predetermined value, the imaging direction is calculated using the geomagnetic sensor 116 on the assumption that the influence on the geomagnetic sensor 116 is small. Further, when the output of the current detection circuit 117 is equal to or greater than a predetermined value, the shooting direction is calculated using the gyro sensor 115 on the assumption that the influence on the geomagnetic sensor 116 is large.

FIG. 2 is a diagram for explaining the calculation principle of the shooting direction using the geomagnetic sensor 116. The microcomputer 113 calculates a geomagnetic vector by subtracting the environmental magnetic field component from the output of the geomagnetic sensor 116 as an offset value. At the same time, the direction of gravitational acceleration is detected from the output of the acceleration sensor 114 and used as camera posture information. As a result, a magnetic north and a shooting azimuth vector are obtained on a plane parallel to the ground surface, and a shooting azimuth angle can be obtained by obtaining an angle formed by the two vectors. When the shooting position is known by GPS or the like, magnetic north and true north may be converted using the shooting position information.
Further, in this embodiment, the shooting direction is obtained, but when the lens optical axis is extremely upward or downward, the direction of the lens optical axis is not obtained, but the direction from the center of the shooting screen to the upper side, etc. The orientation may be obtained with respect to other attention directions.

FIG. 3 is a schematic diagram showing a shooting sequence on the time axis when shooting a single still image. The timing of the series of lens drive, aperture drive, shutter drive, mirror drive, image sensor drive, strobe charge, and strobe light emission described above is shown on the time axis. In FIG. 3, the driving of the display device is omitted.
When blocks such as the lens 100, the aperture 102, the mechanical shutter 104, the mirror 105, the image sensor 103, the strobe 112, and the display device 111 operate, a current flows through each block. That is, the driving current of the lens 100, the driving current of the diaphragm 102, the driving current of the mechanical shutter 104, the driving current of the mirror 105, the driving current of the imaging sensor 103, the charging current of the strobe 112, the emission current of the strobe 112, Drive current.
The magnetic field inside the digital single-lens reflex camera changes as one of the blocks operates. The magnetic field detected by the geomagnetic sensor 116 is a combination of the geomagnetism and the environmental magnetic field, but the environmental magnetic field around the geomagnetic sensor 116 changes as the block of the digital single-lens reflex camera operates. As a result, it becomes difficult to separate the geomagnetism and the environmental magnetic field and accurately calculate only the geomagnetic component.

In FIG. 3, it is assumed that the camera is shooting in one direction. If there is no influence from disturbance, the geomagnetic sensor output should show a constant value. As a result, the geomagnetic sensor output has changed.
In general, factors that adversely affect the geomagnetic sensor include block operating current, motor operating current and motor rotating operation, and movement of parts made of a magnetic material such as iron or nickel. There are many factors that cause these adverse effects inside the digital single-lens reflex camera, and it is not easy to accurately calculate the azimuth using only the geomagnetic sensor 116.

FIG. 4 is an example of the appearance of the digital single-lens reflex camera according to the present embodiment. Since the acceleration sensor 114 and the gyro sensor 115 are not easily affected by changes in the magnetic field, the mounting positions are relatively free. In some cases, the acceleration sensor 114 and the gyro sensor 115 may be mounted on the lens 100, other accessories, or the like, and may not be built in the camera body.
On the other hand, since the geomagnetic sensor 116 is easily affected by changes in the magnetic field, the geomagnetic sensor 116 is located relatively far from noise sources such as the mechanical shutter 104, the mirror 105, and the image sensor 103, such as the left and right ends of the camera body and the vicinity of the pentaprism. It is preferable to mount.

During the series of shooting operations shown in FIG. 3, the microcomputer 113 drives the geomagnetic sensor 116 / acceleration sensor 114 / gyro sensor 115 to calculate the shooting direction.
As described above, the geomagnetic sensor 116 is affected by the operation of a predetermined block during a series of imaging operations. Thus, while the environmental magnetic field is changing, the output of the geomagnetic sensor 116 is not used when calculating the direction, and the output of the gyro sensor 115 is used instead.

FIG. 5 is a diagram showing the switching timing of the geomagnetic sensor 116 and the gyro sensor 115 in the present embodiment.
In FIG. 5, as in FIG. 3, the timing of a series of lens drive, aperture drive, shutter drive, mirror drive, image sensor drive, strobe charge, and strobe light emission when shooting a single still image is on the time axis. Show. As described above, it is assumed that the camera is shooting in one direction. If there is no influence of disturbance, the geomagnetic sensor output shows a constant value.
Therefore, the output of the geomagnetic sensor 116 is used during the period when the geomagnetic sensor output shows a constant value, and the output of the gyro sensor 115 is used during the period when the geomagnetic sensor output has changed.
In the period (a), a current for strobe charging flows. Therefore, the output of the geomagnetic sensor is affected. However, since the current value is almost constant, it can be easily corrected. For this reason, in the period (a), a correct orientation is calculated by correction using a geomagnetic sensor.

FIG. 6 is a diagram for explaining the principle of calculating the shooting direction using the gyro sensor 115.
The gyro sensor 115 can obtain the change in angle by integrating the output, but can obtain only the relative change in angle. Therefore, as the reference absolute azimuth, the azimuth obtained from the output of the geomagnetic sensor 116 before switching to the gyro sensor 115 in FIG. 5 is used.

In the present embodiment, the output of the current detection circuit 117 is used to determine switching between the geomagnetic sensor 116 and the gyro sensor 115.
In a series of imaging sequences, the current detection circuit 117 detects an operating current of a predetermined block.
The microcomputer 113 monitors the output of the current detection circuit 117 while calculating the shooting direction. When the output of the current detection circuit 117 is less than a predetermined value, the imaging direction is calculated using the geomagnetic sensor 116 on the assumption that the influence on the geomagnetic sensor 116 is small. Further, when the output of the current detection circuit 117 is equal to or greater than a predetermined value, that is, when any predetermined block is driven, it is assumed that the influence on the geomagnetic sensor 116 is large, and the shooting direction is calculated using the gyro sensor 115. .

  As shown in FIG. 6, the microcomputer 113 detects the direction of gravitational acceleration from the output of the acceleration sensor 114 and uses it as camera posture information. The timing at which the geomagnetic sensor 116 is switched to the gyro sensor 115 is time T, and the shooting time when shooting is time t. From time T to time t, the output of the gyro sensor 115 is integrated on the ground and a horizontal plane to determine a change in direction. This value is added to the absolute azimuth calculated from the output of the geomagnetic sensor 116 at time T to calculate the shooting azimuth at time t.

  FIG. 7 is a schematic diagram showing a shooting sequence on the time axis when continuous shooting is performed. During continuous shooting, the predetermined block operates more complicatedly, and the period during which the geomagnetic sensor 116 is affected also increases. Even in such a case, by switching between the geomagnetic sensor 116 and the gyro sensor 115, the shooting direction can be calculated without interruption in the shooting sequence, and the highly accurate and accurate shooting direction is always detected. It is possible.

(Second Embodiment)
Next, a second embodiment will be described. In the first embodiment, switching between the geomagnetic sensor 116 and the gyro sensor 115 is performed by detecting the current of a predetermined block by the current detection circuit 117 when calculating the shooting direction. On the other hand, in the second embodiment, switching of the geomagnetic sensor 116 / gyro sensor 115 is performed by detecting the motion of a predetermined member when calculating the shooting direction.
In general, factors that adversely affect the geomagnetic sensor include the block operating current, the motor operating current and the motor rotating operation, and the movement of parts made of magnetic materials such as iron and nickel. Described in the embodiment.

In the present embodiment, an example will be described in which the calculation method of the shooting direction is switched in the case where the geomagnetic sensor 116 is affected by the rotational operation of the motor and the movement of parts made of a magnetic material such as iron or nickel.
In a digital single-lens reflex camera, examples of members that may affect the geomagnetic sensor 116 include a mechanical shutter 104, a mirror 105, a lens AF 101, an aperture 102, and a motor for driving them.

FIG. 8 is a diagram showing the switching timing of the geomagnetic sensor 116 and the gyro sensor 115 in the present embodiment.
In FIG. 8, the timing of a series of lens drive, aperture drive, shutter drive, mirror drive, and image sensor drive when shooting a single still image is shown on the time axis. As described above, it is assumed that the camera is shooting in one direction, and if there is no influence of disturbance, the geomagnetic sensor output should show a constant value.
Therefore, the output of the geomagnetic sensor 116 is used during the period when the geomagnetic sensor output shows a constant value, and the output of the gyro sensor 115 is used during the period when the geomagnetic sensor output has changed.

  The microcomputer 113 constantly monitors the output of the motion detection circuit 118 while calculating the shooting direction. When the output of the motion detection circuit 118 is less than a predetermined value, the imaging direction is calculated using the geomagnetic sensor 116 on the assumption that the influence on the geomagnetic sensor 116 is small. Further, when the output of the motion detection circuit 118 is equal to or greater than a predetermined value, that is, when any predetermined member is moving, the shooting direction is calculated using the output of the gyro sensor 115 on the assumption that the influence on the geomagnetic sensor 116 is large. To do.

  In each of the embodiments described above, when switching from the geomagnetic sensor 116 to the gyro sensor 115, the shooting direction is obtained in consideration of the output of the gyro sensor 115 based on the absolute direction calculated from the value of the geomagnetic sensor 116 at the moment of switching. However, even when switching from the gyro sensor 115 to the geomagnetic sensor 116, it is possible to obtain a shooting direction in consideration of the shooting direction calculated using the output of the gyro sensor 115, so that the user can be made smooth without being aware of the switching of the sensor. Switching can be performed. Specifically, it is desirable to periodically obtain a shooting direction and perform filtering by taking a moving average of them to remove a phenomenon in which the direction changes suddenly.

In addition, there may be a case where the shooting direction calculated using the gyro sensor 115 and the shooting direction calculated using the geomagnetic sensor 116 are different. This is because, when obtaining the geomagnetism from the output of the geomagnetic sensor 116, a process of subtracting the offset of the environmental magnetic field is performed, but this offset may be erroneously estimated.
In such a case, the user is prompted to calibrate the geomagnetic sensor 116. FIG. 9 is a display example that prompts the user to calibrate the geomagnetic sensor 116. By selecting “execute” in this display, the camera enters the calibration mode of the geomagnetic sensor 116. By calibrating the geomagnetic sensor 116 in this way, it is possible to estimate the environmental magnetic field component with high accuracy, and as a result, it is possible to accurately calculate the imaging direction as it was.

As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.
(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

  100: Lens, 101: AF, 102: Aperture, 103: Imaging sensor, 104: Mechanical shutter, 105: Mirror, 106: Switch, 107: Power supply circuit, 108: Battery, 109: Communication interface, 110: Recording device, 111 : Display device, 112: strobe, 113: microcomputer, 114: acceleration sensor, 115: gyro sensor (angular velocity sensor), 116: geomagnetic sensor, 117: current detection circuit, 118: motion detection circuit

Claims (7)

Imaging means;
Power supply,
Geomagnetic detection means;
Angular velocity detection means;
A method of calculating an azimuth using the geomagnetism detection unit and a method of calculating an azimuth using the angular velocity detection unit under certain conditions in a state where power is supplied from the power source to the imaging unit. Control means for switching ;
Current detection means for detecting a current supplied from the power source to the imaging means,
When the current is constant, the control means adopts a method of calculating the azimuth using the geomagnetic detection means, and when the current is not constant, adopts a method of calculating the azimuth using the angular velocity detection means. An imaging device that is controlled to perform. The imaging apparatus according to claim 1 , wherein the control unit calculates the azimuth using the azimuth calculated before switching when the method for calculating the azimuth is switched. The current detection means includes a lens driving current, a diaphragm driving current, a mechanical shutter driving current, a mirror driving current, an imaging sensor driving current, and a strobe charging current as currents supplied from the power source to the imaging means. , the light emission current of the flash, the imaging device according to claim 1 or 2, wherein the detecting at least one of the drive current of the display device. 2. The apparatus according to claim 1, further comprising: a notification that prompts calibration of the geomagnetism detection means when the azimuth calculated using the geomagnetism detection means is different from the azimuth calculated using the angular velocity detection means. The imaging device according to any one of 1 to 3 . A method for controlling an imaging apparatus comprising an imaging means and a power source and having a function of calculating an orientation,
Control for switching between a method for calculating the azimuth using the geomagnetic detection means and a method for calculating the azimuth using the angular velocity detection means under a certain condition in a state where power is supplied from the power source to the imaging means. Steps,
A current detection step of detecting a current supplied from the power source to the imaging means,
In the control step, when the current is constant, a method of calculating an azimuth using the geomagnetic detection means is adopted, and when the current is not constant, a method of calculating an azimuth using the angular velocity detection means is adopted. And a control method for the imaging apparatus. The computer-readable program for functioning a computer as each means of the imaging device of any one of Claims 1 thru | or 4 . A computer-readable storage medium storing the program according to claim 6 .

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