JPH10173970A - Electronic still camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress unnecessary power consumption by automatically powering off the camera when it is decided that the camera is left as it is or being carried continuously for a specific period according to the output of an angular speed sensor mounted on a camera main body. SOLUTION: A microcomputer 10 monitors various signals from an operation part 12 and decides that there is no user operation unless there is signal variation for a specific time to input output digital data of the angular speed sensor 1 for a specific period, thereby evaluating an output waveform. When this output waveform is extremely stable, a 1st state wherein the main body is fixed at an arbitrary position and left as it is is judged. When the amplitude becomes extremely large, a 2nd state wherein the camera main body is being carried without photography is judged. The microcomputer 10 when deciding that the 1st state or 2nd state continues for the specific time controls a power circuit 14 to cut off electric power supply from a battery, thereby placing the camera main body in a power-off state. The sensor waveform is evaluated by comparing the difference between the maximum and minimum values of the output with a reference value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic still camera for capturing a still image.

[0002]

2. Description of the Related Art In an electronic still camera capable of electronically capturing a digital still image by an image pickup device such as a CCD imager, an auto timer is set to automatically turn off a power supply in order to reduce useless battery consumption. Features have been added. This means that the camera is turned on
This function automatically turns off the power of the camera when a certain period of time has elapsed without any operation. In general, the time until the power is turned off is often set to about several minutes, during which time the camera maintains an energized state.

In general, an electronic still camera is used with a battery power supply, and is often used mainly in a portable manner. Therefore, improvement in performance regarding power consumption is an important issue for the camera. In recent years, electronic still cameras equipped with an LCD monitor have appeared on the market.
It is expected that this specification will become mainstream, and the demand for power saving will be more severe than ever.

The conventional method has a drawback that the power is not turned off until a certain time elapses, and power is easily wasted. To save power, simply shortening the set time until the power is turned off results in poor operability, such as immediately switching to the OFF state despite maintaining the power on state. And both power saving effects could not be satisfied.

A system for saving power by incorporating an angular velocity sensor in a camera body in order to discriminate between use and carrying is disclosed in Japanese Patent Laid-Open No. 4-90273 (H04N5 / 2005).
225). In this system, the camera incorporates a contact switch that outputs a contact detection signal by pressing the palm of the hand that supports the grip, and an angular velocity sensor that detects camera vibration. The contact switch and angular velocity sensor detect the state of the camera being carried while being vibrated while holding the grip of the camera body, and when this state is detected, the auto power off function operates. ing.

[0006]

In the prior art, the user cannot shake the grip portion of the camera, for example, when the camera is left on a desk, not only does the auto power off function not work, but also the There is a problem that the auto power-off function does not operate as in the idle state because the grip section is not provided when being carried in a state where it is stored in a storage device.

[0007]

According to the present invention, there is provided a first state in which a main body of a camera is fixed and left at an arbitrary position;
A second state in which the camera is being carried without taking a picture, and a third state in which the user is manually fixing the picture while taking or preparing to take a picture.
State determining means for determining the three states based on the output of the angular velocity sensor attached to the camera; and a first state or a second state
Determining means for determining whether or not one of the states has continued for a predetermined period;
When it is determined that any one of the states has been continued for a predetermined period, the power supply from the battery is cut off to set the power off state, and the state determination unit determines the difference between the maximum value and the minimum value of the sensor output. Is compared with a first reference value and a second reference value larger than the first reference value. If the difference is smaller than the first reference value, it is determined to be in the first state, and if the difference is larger than the second reference value, , The second state. Further, as another means, the sensor output is integrated over a predetermined period, and the integrated value is compared with a third reference value and a fourth reference value larger than the third reference value. If it falls below 1st
The state is determined, and when the integrated value exceeds the fourth reference value, the state is determined to be the second state.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic diagram of a digital still camera (electronic still camera) on which the angular velocity sensor 1 is mounted. In the case of the present embodiment, the angular velocity sensor 1 is built in and fixed to the cabinet bottom 3 below the lens 2 of the camera body. At the time of photographing and at the time of preparation immediately before photographing, the user is in a state (handling state) in which the side surface 5 of the cabinet 4 of the camera is firmly held in order to prevent camera shake. However, in a state where the camera is carried in a bag or the like, there is no need to be aware of camera shake, and it is expected that the camera is completely disorderly. When the camera is left on the desk, it is expected that a state with almost no vibration will be continued.

If the difference between these states is determined by the output of the angular velocity sensor 1, the state where the camera is placed can be detected.

FIG. 3 shows an example of the output waveform of the angular velocity sensor output in each state, with the vertical axis representing the output voltage from the angular velocity sensor 1 and the horizontal axis representing time. FIG. 3A shows an output waveform in the handling state. In this handling state, since the user holds the camera cabinet, a large change in angular velocity does not occur continuously, and an output of an almost stable change in angular velocity occurs. FIG. 3B shows a state where the apparatus is left on a desk, and almost no change in angular velocity occurs because the apparatus is almost stationary. FIG. 3C shows a state in which the camera is being carried. Since a random vibration is continuously applied, a waveform having a large angular velocity change is generated.

As described above, these three types of states can be determined based on the characteristics of the waveform of the output of the angular velocity sensor 1.

Next, a block diagram of the digital still camera will be described with reference to FIG. In the figure, reference numeral 20 denotes an A / D converter for converting the output voltage of the angular velocity sensor 1 into a digital value, 10 denotes a digital sensor output from the A / D converter 20, a power ON / OFF control signal from a power switch 11, and a release. The microcomputer is a microcomputer that receives various control signals from an operation unit 12 including various operation switches such as a button 6, a flash switching button, and a self-timer switch, and controls the power supply circuit 14.

The power supply circuit 14 is turned on by the microcomputer 10
When the command is issued, the camera body is turned on, and the output current from the battery 13 is supplied to a camera unit (not shown) such as a CCD imager or a signal processing unit (not shown) for processing a captured image signal. When a power-off command is issued from the microcomputer 10, the power supply control operation is performed in which the supply of the output current from the battery 13 to the camera unit or the signal processing unit is cut off and the camera body is turned off.

Next, the operation of the block diagram configured as described above will be described with reference to the flowchart of FIG. First, in step 50, the user operates the power switch 11
Is turned on. When it is determined that the power switch 11 is in the ON state by this determination, the microcomputer 10 issues a power ON command to the power supply circuit 14 to turn on the camera body including the angular velocity sensor 1, and accordingly, the angular velocity sensor 1 is activated (step 51).
Further, in step 52, the microcomputer 10 monitors various control signals from the operation unit 12, and determines whether or not the user is operating the operation unit 12. If it is recognized that there is a user operation, that is, if any of the various control signals from the operation unit 12 has changed, it is determined that there is a user operation, and the process does not proceed to the next step. Repeat the operation.

If it is determined that there is no user operation, the microcomputer 10 outputs the digital data of the angular velocity sensor 1 for a predetermined period (for example, about 5 seconds) in step 53.
Then, as shown in step 54, the output waveform of the sensor output is evaluated. In this waveform evaluation, specifically, the maximum value and the minimum value in the digital data of the sensor output taken in are detected, and the difference S between the maximum value and the minimum value is calculated. When it is smaller than the threshold value R1, it is determined that a waveform having a large amplitude is not obtained in the output of the angular velocity sensor 1, and it is determined that the state is the idle state. Also,
When the difference S is equal to or larger than the first threshold value R1 and smaller than the second threshold value R2, it is determined that a waveform having a certain amplitude is obtained in the output of the angular velocity sensor 1, and it is determined that the state is the handling state. Further, when the difference S is equal to or more than the second threshold value R2, it is determined that a waveform having an extremely large amplitude is obtained in the output of the angular velocity sensor 1, and it is determined that the portable device is in the carrying state. The first
The threshold value R1 and the second threshold value R2 are set in advance as optimum values that allow the camera to be experimentally set in three states and distinguish each state.

As described above, three types of state determination are executed based on the output of the angular velocity sensor 1, and in step 55, whether the camera is in the idle state or the portable state, that is, whether the user does not operate the camera or not is determined. If it is determined that the vehicle is not in such a state, that is, if it is determined that the vehicle is in the handling state, the process returns to step 52 and the same operation is repeated. Starts the counting of the built-in timer counter in step 59 and proceeds to step 56.

In step 56, it is determined whether or not the count value of the timer counter has exceeded a count value corresponding to 30 seconds.
And the same operation is repeated.
If there is no operation in step 52, and if it is determined in step 55 that the same state as the previous state has been continued by the evaluation of the output waveform in step 54, the timer is determined in step 59. The process proceeds to step 56 while maintaining the count of the counter as it is. If it is determined that the handling state has been reached, the timer counter is cleared and stopped at step 58, and
Return to 2. In step 59, the microcomputer 10 operates to start the timer counter if it is in the stopped state, and to continue the operation if it is already in the operating state.

In this manner, the operation unit 12 is determined by several determinations.
If no operation is performed, the neglected state or the carrying state is continued, and if it is determined in step 56 that this state has been continued for 30 seconds or more, the process proceeds to step 57 and a power OFF command is issued to the power supply circuit 14. It is emitted and the camera body is de-energized. Thus, a series of processing is completed.

As described above, by judging the state of the camera based on the output of the angular velocity sensor and realizing the auto power off function, it is possible to greatly reduce the power consumption of the battery 13 due to unnecessary energization. Become.

In the above-described embodiment, when evaluating the waveform of the sensor output, the maximum value and the minimum value of the fetched sensor output are detected and the difference between the two values is calculated to determine the maximum amplitude of the sensor output, thereby obtaining the threshold value. However, in this method, even in the handling state, erroneous detection may occur when the camera shake temporarily occurs and the amplitude increases. Therefore, another embodiment shown in FIG. 5 is effective to suppress the influence of the temporary fluctuation.

In another embodiment of FIG. 5, the A / D converter 20
4 in that an absolute value conversion circuit 21 and a digital integrator 22 are inserted between the microcomputer 10 and the microcomputer 10. The flowchart of FIG. The difference is that the integration value is taken in. That is, the sensor output is A / D
After conversion into a digital value by the converter 20, the negative data lower than the zero level is converted into an absolute value by the absolute value converting circuit 21 and changed to positive data. The digital integration is performed over a predetermined period (for example, about 5 seconds) at
0, and this integrated value is used for waveform evaluation instead of the difference S. In other words, the integrated value corresponds to the area of each waveform in FIG. 3, and it is noted that the greater the integrated value, the larger the waveform of the sensor output. This integrated value is referred to as the third threshold R3 and the third threshold. If the integrated value is smaller than the third threshold value and the integrated value is smaller than the third threshold value, it is determined that the vehicle is in the idle state where the amplitude is extremely small. If it is smaller than the value, it is in the handling state, and if it is more than the fourth threshold,
It is determined that the portable terminal is in a carrying state where the amplitude is extremely large.
Note that the third and fourth thresholds are optimal values set in advance by experiments, similarly to the first and second thresholds in the above embodiment.

In any of the above embodiments, if the power is automatically turned off in step 57, the power switch 11 must be operated again to execute the next photographing. Power needs to be cycled.

In both of the above embodiments, the time is set to 30 seconds until the power is turned off after the neglected state or the carrying state is continued. However, if the time is such that the operability of the user is not impaired, it is particularly 30 seconds. However, the present invention is not limited to this. If the microcomputer 10 selects the self-timer mode by the self-timer switch and operates the self-timer, the series of operations from step 51 to step 57 in FIG. 3 is prohibited. It is possible to avoid the risk of power-off due to erroneous detection of an idle state. In FIG. 2, the angular velocity sensor 1 can be built in the cabinet.

Although the angular velocity sensor is used to detect the vibration applied to the digital still camera, other types of sensors having the same effect can be used without any problem.

[0025]

As described above, according to the present invention, when it is determined that the first state in which the camera should be deactivated and the second state in which the camera is carried for a predetermined period of time, Then, the power is automatically turned off, and wasteful power consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a digital still camera according to an embodiment of the present invention.

FIG. 3 is a diagram showing an output waveform of an angular velocity sensor according to one embodiment of the present invention.

FIG. 4 is a flowchart of one embodiment of the present invention.

FIG. 5 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angular velocity sensor 10 Microcomputer 14 Power supply circuit 13 Battery 22 Digital integrator

Claims (3)

[Claims] 1. An electronic still camera having vibration detecting means and being activated by receiving power supply from a battery, wherein a first state in which a main body is fixed and left at an arbitrary position and an image is taken. A second state that is being carried without
3rd that the user holds during shooting or preparation for shooting
State determination means for determining three states of the state based on the output of the vibration detection means, and determination means for determining whether any of the first state or the second state has continued for a predetermined period, An electronic still camera, wherein when the determination means determines that either the first state or the second state has been continued for a predetermined period, the power supply from the battery is cut off and the power is turned off. 2. The apparatus according to claim 1, wherein said vibration detecting means includes an angular velocity sensor, and said state determining means determines a difference between a maximum value and a minimum value of said sensor output as a first reference value and a second reference value larger than said first reference value. The value is determined to be the first state when the difference is smaller than the first reference value, and is determined to be the second state when the difference is greater than the second reference value. Electronic still camera. 3. The vibration detecting means comprises an angular velocity sensor, and the state determining means integrates the sensor output over a predetermined period, and makes the integrated value larger than a third reference value and the third reference value. When the integrated value is lower than the third reference value, the first state is determined, and when the integrated value is higher than the fourth reference value, the second state is determined. The electronic still camera according to claim 1.