JP2010038681A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save electricity of a GPS module-loaded electronic apparatus having a positioning function, such as an electronic camera, a cellular phone, a personal computer, a PDA or the like. <P>SOLUTION: The electronic apparatus 1 includes: a positioning means 20 for acquiring positional information; a memory means 20b for storing new information acquired by the positioning means 20; main circuits 12, 13, 14, 15, 16, 17 and 18; a power switch 21 for directing turn-on/off operations of supplying power from a battery to the main circuits 12, 13, 14, 15, 16, 17 and 18; and a control means 19 which brings the positioning means 20 to repeat its start and its stop following the start for every first prescribed period, in such the state that the turn-off operation of the power switch 21 is carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device.

  A GPS receiver that performs positioning by receiving a signal from a GPS satellite is known (see Patent Document 1). The GPS receiver periodically performs positioning and stores it, and sends the latest stored positioning result in response to a position detection request from the external device to the GPS receiver. If positioning cannot be performed for a certain time, the operation is temporarily stopped.

JP-A-10-20014

  When a conventional GPS receiver is mounted on a battery-driven electronic device, the following problems occur. That is, since the power switch of the electronic device must be turned on in order to operate a control circuit that requires the GPS receiver to detect the position, power consumption increases.

  An electronic apparatus according to the present invention includes a positioning unit that acquires position information, a storage unit that stores new information acquired by the positioning unit, a main circuit unit, and on / off of power supply from a battery to the main circuit unit. And a control means for causing the positioning means to repeatedly start and stop after the startup every first predetermined time when the power switch is turned off. .

  According to the present invention, it is possible to save power in an electronic device having a positioning function.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of an electronic camera 1 according to an embodiment of the present invention. In FIG. 1, an electronic camera 1 includes a photographing optical system 11, an image sensor 12, an AFE (Analog front end) circuit 13, an image processing circuit 14, an LCD monitor 15, a RAM 16, a flash memory 17, and a CPU 18. A sub CPU 19, a GPS module 20, an operation member 21, and a power control circuit 22.

  The CPU 18, RAM 16, flash memory 17, image processing circuit 14, and LCD monitor 15 are each connected via a bus 23.

  The photographing optical system 11 includes a plurality of lens groups including a zoom lens and a focusing lens, and forms a subject image on the light receiving surface of the image sensor 12. In order to simplify FIG. 1, the photographing optical system 11 is shown as a single lens.

  The image sensor 12 is configured by a CCD image sensor, a CMOS image sensor, or the like in which the light receiving elements are two-dimensionally arranged on the light receiving surface. The image sensor 12 photoelectrically converts a subject image by a light beam that has passed through the photographing optical system 11 to generate an analog image signal. The analog image signal is input to the AFE circuit 13.

  The AFE circuit 13 performs analog processing such as correlated double sampling and gain adjustment on the analog image signal, and converts the image signal after the analog processing into digital image data. The digital image data is input to the image processing circuit 14. The image processing circuit 14 performs various types of image processing (color interpolation processing, gradation conversion processing, contour enhancement processing, white balance adjustment processing, image compression processing, image expansion processing, etc.) on the digital image data.

  The LCD monitor 15 is constituted by a liquid crystal panel, and displays an image, an operation menu screen, and the like according to an instruction from the CPU 18. The RAM 16 is used as a work memory for the CPU 18. The RAM 16 temporarily stores digital image data in the pre-process and post-process of image processing by the image processing circuit 14. The flash memory 17 stores a program to be executed by the CPU 18.

  The CPU 18 controls an operation performed by the electronic camera 1 by executing a program stored in the flash memory 17. The CPU 18 also performs AF (autofocus) operation control and automatic exposure (AE) calculation. The AF operation uses, for example, a contrast detection method for obtaining a focus position of a focusing lens (not shown) based on contrast information of a through image. The through image refers to a monitor image that is repeatedly acquired by the image sensor 12 at a predetermined time interval (for example, 30 frames / second) before a shooting instruction.

  The operation member 21 includes a main switch, a release button, a menu switch, and the like. The operation member 21 sends an operation signal corresponding to each operation such as a main switch operation, a release operation, and a menu selection operation to the sub CPU 19. The sub CPU 19 is activated when a battery (not shown) is loaded in the electronic camera 1 and monitors input of an operation signal from the operation member 21, and also instructs the power supply control circuit 22 to start / end power supply. To do.

  When the sub CPU 19 receives an operation signal indicating an operation of turning on the main switch, the sub CPU 19 instructs the power supply control circuit 22 to start power supply. Further, when the sub CPU 19 receives the operation signal indicating the main switch OFF operation, the sub CPU 19 requests the CPU 18 to perform the power OFF process, and instructs the power control circuit 22 to end the power supply after the power OFF process ends.

  The power supply control circuit 22 is configured to be able to control supply / non-supply of power to the GPS module 20 and power to other blocks independently. That is, it is possible to operate only the GPS module 20 with the main switch of the electronic camera 1 turned off, or to deactivate only the GPS module 20 with the main switch of the electronic camera 1 turned on. . The setting to activate / deactivate the GPS module 20 is set in advance by a menu operation, and the setting content is stored in the flash memory 17. In the present embodiment, a case where the setting of “operating the GPS module 20” is performed will be described as an example.

  The GPS module 20 receives radio waves from the GPS satellites 201 and 202 and calculates positioning information (latitude, longitude, altitude) using information carried on the received signal. In FIG. 1, only two GPS satellites are shown. The positioning information calculated by the GPS module 20 is overwritten and stored in a predetermined area of the nonvolatile memory 20b in the GPS module 20.

<Positioning process>
Here, positioning by the GPS module 20 will be described. The GPS module 20 acquires almanac data and ephemeris data from signals transmitted from the GPS satellites 201 and 202, respectively. The almanac data includes information on the orbits of all the GPS satellites (24 aircraft), and the ephemeris data includes position information and time information for each satellite. The GPS module 20 selects four satellites used for positioning based on the almanac data, and calculates its own position based on signals transmitted from the selected four satellites.

  When positioning is repeated, if the satellite position information and orbit information (GPS data) are stored, the stored information can be used at the next positioning. However, the position information of the satellite requires new position information when a predetermined time (for example, 4 hours) elapses, and the orbit information requires new orbit information after a predetermined period (for example, 2 weeks). . Therefore, since the stored information cannot be used when the measurement interval is opened from the previous measurement, it is necessary to newly acquire at least one of the satellite position information and the orbit information.

  In general, it is “Cold” when it is necessary to newly acquire almanac data and ephemeris data at the time of positioning, “Warm” when it is necessary to acquire only ephemeris data at the time of positioning, and almanac data at the time of positioning. And the state that does not require new acquisition of ephemeris data is called “hot”. The GPS module 20 changes the data to be newly acquired depending on which of the three states corresponds. If it is not necessary to acquire new data, the time required to acquire the data can be omitted, so the positioning time is (when starting from “cold”)> (when starting from “warm”)> (“hot” ”At the start from“).

  In the electronic camera 1 of the present embodiment, the GPS module 20 can be started at a predetermined timing even when the main switch of the electronic camera 1 is turned off so that the GPS module 20 can always start from “hot” (so-called hot start). Power is supplied to and the positioning information is calculated. Then, the GPS module 20 stores the calculated positioning information in a predetermined area of the nonvolatile memory 20b. That is, the positioning information in the memory 20b is periodically updated even when the main switch of the electronic camera 1 is turned off. Note that the positioning information to be updated includes GPS data.

  When the setting for storing the positioning information of the shooting point in association with the shot image is performed, the CPU 18 generates an Exif format image file including the data of the shot image and the positioning information, and stores the image file in a memory card (not shown). Record an image file.

  Specifically, when the sub CPU 19 receives an operation signal indicating that the release button is turned on, the sub CPU 19 notifies the CPU 18 that an instruction to start photographing has been issued. The CPU 18 sends an instruction to each block in FIG. 1 to start photographing processing.

  The Exif format image file is obtained by embedding data such as thumbnail images and shooting information in image data in the JPEG image format. This file structure has a tag area for recording image attached information and an image data area for recording captured image data. The CPU 18 reads the positioning information stored in a predetermined area of the memory 20b of the GPS module 20 through the sub CPU 19 at the time of shooting, and generates the image file by including the read positioning information in the tag area.

<Power-off processing>
Since the present embodiment is characterized by the operation of the electronic camera 1 in a state where the main switch is turned off, the processing performed by the sub CPU 19 when the main switch is turned off will be mainly described with reference to the flowchart of FIG. The sub CPU 19 is activated when the battery (not shown) is loaded in the electronic camera 1 and the main switch is turned off from the on state (referred to as power off), and starts the processing shown in FIG.

  In step S1 of FIG. 2, the sub CPU 19 resets the counter and proceeds to step S2. The counter counts the number of times the GPS module 20 is activated in the power off state.

  In step S2, the sub CPU 19 determines whether or not the camera is on. The sub CPU 19 makes an affirmative decision in step S <b> 2 when a signal indicating an on operation of the main switch is input from the operation member 21, and ends the process of FIG. 2. In this case, the process proceeds to power-on processing.

  On the other hand, the sub CPU 19 makes a negative determination in step S2 when the signal indicating the on operation of the main switch is not input from the operation member 21, and proceeds to step S3. In step S3, the sub CPU 19 determines whether or not a predetermined time (restart time) has elapsed since the start of the process of FIG. When a predetermined restart time (for example, 2 hours) has elapsed, the sub CPU 19 makes a positive determination in step S3 and proceeds to step S4. The restart time is set in the sub CPU 19 in advance so as to be shorter than the above four hours so that the hot start can be performed.

  If the restart time has not elapsed, the sub CPU 19 makes a negative determination in step S3 and returns to step S2. In this case, the elapsed time from the time when the processing according to FIG. 2 is started is continued. In step S4, the sub CPU 19 determines whether or not the count value by the counter has reached a specified number. If the count value has reached a predetermined number of times (for example, 5 times), the sub CPU 19 makes an affirmative decision in step S4 and ends the process of FIG. In this case, the number of restarts is limited so that the GPS module 20 is not started more than 5 times in the power-off state.

  On the other hand, if the count value has not reached a predetermined number of times (for example, 5 times), the sub CPU 19 makes a negative determination in step S4 and proceeds to step S5. In step S5, the sub CPU 19 sends an instruction to the power control circuit 22, starts supplying power to the GPS module 20, and proceeds to step S6. As a result, the GPS module 20 restarts and starts the positioning operation. The power supply is performed for the GPS module 20, and power is not supplied to other camera blocks.

  In step S6, the sub CPU 19 increments the counter by 1 and proceeds to step S7. In step S <b> 7, the sub CPU 19 determines whether or not the positioning information has been updated in the GPS module 20. If the positioning information including GPS data has been updated, the sub CPU 19 makes a positive determination in step S7 and proceeds to step S9. If the positioning information has not been updated, the sub CPU 19 makes a negative determination in step S7 and proceeds to step S8. In step S7, when the positioning information is updated, the positioning operation is terminated at that time.

  In step S8, the sub CPU 19 determines whether or not a predetermined time (positioning time) has elapsed since the start of power supply to the GPS module 20. If the positioning time (for example, 3 minutes) has elapsed, the sub CPU 19 makes a positive determination in step S8 and proceeds to step S9. As the positioning time, a time sufficient for normal positioning is set in the sub CPU 19 in advance. If the positioning time (for example, 3 minutes) has not elapsed, the sub CPU 19 makes a negative determination in step S8 and returns to step S7. In step S8, the positioning operation is limited not to continue for more than 3 minutes.

  In step S9, the sub CPU 19 sends an instruction to the power control circuit 22, ends the power supply to the GPS module 20, and returns to step S2. As a result, the GPS module 20 ends the positioning operation.

According to the embodiment described above, the following operational effects can be obtained.
(1) In the electronic camera 1, the main switch 21 for instructing on / off of power supply from the battery to the main circuit portion (other blocks 12, 13, 14, 15, 16, 17, 18) is turned off. In this state, the GPS module 20 is repeatedly activated and stopped after the activation every restart time (for example, 2 hours). Since the information acquired by the GPS module 20 is stored in the nonvolatile memory 20b, the latest positioning information obtained when the main switch is turned off can be held. Furthermore, power consumption can be suppressed compared to the case where the GPS module 20 is always activated.

(2) Since the sub CPU 19 limits the number of times the GPS module 20 is activated after the main switch 21 is turned off from the on state to a predetermined number of times, the power consumption can be suppressed as compared with the case where the operation is performed indefinitely.

(3) The sub CPU 19 stops the GPS module 20 when new information is stored in the non-volatile memory 20b after starting the GPS module 20. Therefore, the sub CPU 19 continues to start the GPS module 20 even after acquiring the information. Power consumption can be reduced compared to.

(4) Since the sub CPU 19 stops the GPS module 20 when the positioning time (for example, 3 minutes) elapses after the GPS module 20 is started, it is consumed as compared with the case where the GPS module 20 is started more than necessary. Power can be reduced.

(5) Since the control is performed by the sub CPU 19 different from the CPU 18, the power consumption can be suppressed as compared with the case where the CPU 18 is operated when the main switch is turned off. In the case of a camera using a battery as a power source, power consumption is particularly useful because battery consumption leads to incapability of photographing.

(6) The restart time is set to a predetermined time so that the GPS module 20 performs positioning (so-called hot start) using information (GPS data) acquired at the time of the previous positioning, so a cold start or a warm start is performed. Since the time required for positioning is shortened compared to the case, power consumption can be suppressed.

(Modification 1)
Although the processing according to FIG. 2 has been described as being performed when the power is turned off, that is, when a battery (not shown) is loaded in the electronic camera 1 and the main switch is turned from on to off, it is also performed during the following power saving operation. You may do it. That is, the sub CPU 19 performs the process shown in FIG. 2 even when the power supply control circuit 22 ends the power supply and switches to the standby state because the predetermined timer-off time has elapsed while the operation member 21 is not operated. Let it begin.

  In the process of step S2 in this case, the sub CPU 19 makes a positive determination in step S2 when a signal indicating that any of the operation members 21 has been operated is input from the operation member 21, and ends the process of FIG. To do. On the other hand, when the non-operation state of the operation member 21 is continued, the sub CPU 19 makes a negative determination in step S2 and proceeds to step S3.

(Modification 2)
The two hours exemplified as the restart time determined in step S3, the five times exemplified as the specified number of times determined in step S4, and the three minutes exemplified as the positioning time determined in step S8 may be appropriately changed. Further, when the electric power from the external power source is supplied to the electronic camera 1, the number of times illustrated in step S4 is increased five times (for example, ten times or unlimited), or the time period illustrated in step S8 is extended for three minutes. (For example, 10 minutes).

(Modification 3)
Although the electronic camera 1 equipped with the GPS module 20 has been described as an example, the present invention may be applied to an electronic device such as a mobile phone, a personal computer, or a PDA equipped with the GPS module 20.

  The above description is merely an example, and is not limited to the configuration of the above embodiment.

1 is a block diagram of an electronic camera according to an embodiment of the present invention. It is a flowchart which illustrates the flow of the process which a sub CPU performs at the time of a main switch OFF.

Explanation of symbols

1 ... Electronic camera 18 ... CPU
19 ... Sub CPU
20 ... GPS module 20b ... Memory 21 ... Operation member 22 ... Power supply control circuit

Claims (6)

Positioning means for acquiring position information;
Storage means for storing new information acquired by the positioning means;
Main circuit part,
A power switch for instructing on / off of power supply from a battery to the main circuit unit;
An electronic apparatus comprising: control means for causing the positioning means to repeatedly start and stop after the start-up every first predetermined time while the power switch is turned off. The electronic device according to claim 1,
The electronic device is characterized in that the control means limits the number of times the positioning means is activated after the power switch is turned off from an on state to a predetermined number. The electronic device according to claim 1,
The electronic device is characterized in that the control means stops the positioning means when new information is stored in the storage means after starting the positioning means. The electronic device according to claim 1,
The electronic device according to claim 1, wherein the control unit stops the positioning unit when a second predetermined time has elapsed after the positioning unit is activated. The electronic device according to claim 1,
The main circuit unit includes an imaging unit,
The electronic device is characterized in that the control means is constituted by a sub CPU different from a main CPU that controls the imaging means. The electronic device according to claim 1,
The electronic apparatus according to claim 1, wherein the first predetermined time is determined so as to perform positioning using information acquired by the positioning means at the previous positioning.

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