JP2021150762A - Image capture device and control method thereof - Google Patents

Abstract

To provide: an image capture device which can predict a video recordable time on the assumption that video recording is started, during video standby before video recording; and a control method thereof.SOLUTION: An image capture device capable of capturing a moving image comprise: recording means to record moving image data; temperature detection means to measure the temperature inside the image capture device; and operable time prediction means to predict an operable time to a stop time point, at which an operation needs to be stopped because a temperature measurement by the temperature detection means is greater than or equal to a prescribed temperature. In a video standby state where the moving image data is not recorded on the recording means, the operable time prediction means predicts the operable time from transition to a video recording state where the moving image data is recorded on the recording means.SELECTED DRAWING: Figure 5

Description

The present invention relates to an image pickup apparatus and a control method thereof, and more particularly to an image pickup apparatus having an electronic device that generates heat with operation.

In recent years, small but highly functional portable electronic devices such as digital cameras and mobile phones have become widespread. For example, even if a digital camera has the same video recording function, it is possible to perform image processing such as more advanced filtering and image correction on image data with higher pixels and record it at a higher frame rate. .. In addition, functions other than shooting are being adopted, such as the ability to wirelessly transfer captured still images and video files.

In order to realize these functions, electronic devices such as an image sensor, a wireless module, and an image processing CPU serve as heat sources, and the temperature inside the digital camera housing rises. Therefore, it is necessary to limit the operation so as not to exceed the operation guarantee upper limit temperature of the electronic device. In addition, an increase in the temperature of the image sensor causes deterioration of the captured image. In addition, since the electronic device is mounted in a small housing, the exterior of the housing also generates heat during operation. Since the exterior of the housing is a part that the user directly touches, it is necessary to control the temperature so that it is below a predetermined temperature.

Patent Document 1 is an imaging device that calculates and displays the time until the temperature inside the housing reaches the moving image recording stop time from the amount of change in the measured value of the thermometer arranged inside the camera housing during movie shooting. It is disclosed. The image pickup apparatus of Patent Document 1 stops moving image recording when a predetermined temperature is reached.

Japanese Unexamined Patent Publication No. 2012-165372

In the prior art disclosed in Patent Document 1 described above, the moving image recording is stopped when the moving image recording needs to be stopped due to the temperature rise of the housing of the digital camera. As a result, the temperature of the housing of the digital camera can be controlled to be equal to or lower than the predetermined temperature. Further, by displaying the time from the start to the stop of the video recording, the user can be notified in advance of the stop of the video recording.

However, in the image pickup apparatus disclosed in Patent Document 1, the time until the housing reaches a predetermined temperature cannot be predicted unless moving image recording is started. Therefore, after the user starts the video recording, the video recording time expected by the user before the start of the recording may not be reached, and the necessary scene may not be recorded.

Therefore, an object of the present invention is to provide a means capable of predicting the operable time when the predetermined function is executed while waiting before executing the predetermined function.

In order to achieve the above object, the present invention executes a temperature sensor that acquires the temperature of a predetermined location of the own device, a control means that limits the function based on the temperature of the predetermined location, and the function. Previously, based on the current temperature acquired by the temperature sensor and the information on the time-dependent temperature change of the predetermined location when the function is executed, the operation is possible until the function is limited by the control means. It is characterized by having a predictive means for calculating time.

According to the present invention, it is possible to predict the operable time when the predetermined function is executed during the standby before executing the predetermined function.

It is an external view of the digital camera 100 which concerns on 1st Embodiment. It is a block diagram which shows the structural example of the digital camera 100 which concerns on 1st Embodiment. It is a figure which shows the arrangement example of the temperature sensor inside the digital camera 100 housing which concerns on 1st Embodiment. It is a figure which shows the time-dependent change of the output value of the temperature sensor inside the digital camera 100 housing which concerns on 1st Embodiment. It is a moving image recordable time prediction control flow of the digital camera 100 which concerns on 1st Embodiment. This is an example of the display screen of the digital camera 100 according to the first embodiment. It is a figure which shows the temperature change every time in the housing of a digital camera during the conventional video recording.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description of the following embodiments, the same components, operations, and processes are designated by the same reference numerals in the drawings. Further, in the present embodiment, as the electronic device according to the present invention, a digital camera which is an imaging device will be described as an example, but the present invention is not limited to this.

First, with reference to FIG. 7, control of operation limitation due to temperature rise of a conventional digital camera will be described. FIG. 7 is a diagram showing an example of the time-dependent temperature change inside the housing of the digital camera during video recording.

Curve 701 shows the time-dependent temperature change inside the housing of the digital camera during video recording. Curve 702 shows the time-dependent temperature change inside the housing of the digital camera during the moving image standby before the moving image recording. During the moving image standby, the moving image coding process by the image processing unit and the moving image data writing process to the recording medium do not occur, so that the temperature rise in the housing becomes slower than during the moving image recording.

For example, if the operating temperature limit and K _L, in some circumstances a temperature K _E, the during movie recording (curve 701), reaching the operating limit temperature from the start of video recording at time t _1. That is, when the moving image recording is started, the time t ₁ is the moving image recording possible time. Meanwhile, during the moving stand (curve 702), it does not reach the operating temperature limit _{K L.}

Next, the curve 703 shows the temperature change for each time inside the housing when the moving image recording is started at _{the time t S during the moving image standby.} At this time, it reaches a moving stop temperature K _L from the start of video recording at time t _2. That is, in this case, the moving image recordable time assumed before the start of recording becomes shorter after the actual start of recording.

Therefore, since the temperature rise rate inside the housing differs between the video standby and the video recording, the method of observing the temperature change amount of the thermometer cannot predict the _{video recordable time t 2 during the video standby.} ..

(First Embodiment)
An imaging device, which is an electronic device to which the present invention can be applied, will be described with reference to FIG. FIG. 1 is an external view showing a digital camera 100 as an example of the image pickup apparatus according to the first embodiment. FIG. 1A is a front perspective view of the digital camera 100, and FIG. 1B is a rear perspective view of the digital camera 100.

The communication terminal 101 is a communication terminal for the digital camera 100 to communicate with the lens unit 200 (detachable) described later.

The terminal cover 102 is a cover for protecting a connector (not shown) for connecting an external device such as a connection cable.

The outside viewfinder display unit 103 is a display unit provided on the upper surface of the camera, and displays set values of the digital camera 100 such as a shutter speed and an aperture.

The mode changeover switch 104 is an operation unit for switching various modes related to shooting and playback.

The shutter button 105 is an operation unit for giving a shooting instruction. For example, a half press (SW1) generates a shooting preparation instruction, and a full press (SW2) executes shooting.

The grip portion 106 is a holding portion having a shape that makes it easy for the user to hold the digital camera 100 with his / her right hand. In the present embodiment, the shutter button 105 and the main electronic dial 171 described later are arranged at positions that can be operated by the index finger of the right hand while holding the digital camera by holding the grip portion 106 with the little finger, ring finger, and middle finger of the right hand. ing. Further, in the same state, a sub electronic dial 173, which will be described later, is arranged at a position where it can be operated with the thumb of the right hand.

The display unit 107 displays an image and various kinds of information. The display unit 107 is provided with a touch panel 170a on its surface, and the touch panel 170a can detect a touch operation on the display surface (operation surface) of the display unit 107.

The eyepiece 108 is an eyepiece of an eyepiece finder (a peep-type finder), and the user visually recognizes an image displayed on the internal EVF213 (Electric Viewfinder) described later via the eyepiece 108. be able to.

The eyepiece detection unit 109 is an eyepiece detection sensor that detects whether or not the user is in contact with the eyepiece unit 108.

The lid 110 is a lid of a slot that stores a recording medium 260, which will be described later.

The main electronic dial 171 is a rotation operation member, and by turning the main electronic dial 171, it is possible to change set values such as a shutter speed and an aperture.

The power switch 172 is an operating member that switches the power of the digital camera 100 on and off.

The sub electronic dial 173 is a rotation operation member, and can move a selection frame, feed an image, and the like.

The cross key 174 is a cross key (four-way key) capable of pushing up, down, left, and right portions, respectively. The operation can be performed according to the pressed portion of the cross key 174.

The SET button 175 is a push button and is mainly used for determining a selection item or the like.

The moving image button 176 is used to instruct the start and stop of moving image shooting (recording).

The exposure state can be fixed by pressing the AE lock button 177 in the shooting standby state.

The enlargement button 178 is an operation button for turning on / off the enlargement mode in the live view display of the shooting mode. By operating the main electronic dial 171 after turning on the enlargement mode, the live view image can be enlarged or reduced. In the playback mode, it functions as an enlargement button for enlarging the reproduced image and increasing the enlargement ratio.

The play button 179 is an operation button for switching between the shooting mode and the play mode. By pressing the playback button 179 during the shooting mode, the playback mode can be entered, and for example, the latest image among the images recorded on the recording medium 260 described later can be displayed on the display unit 107.

When the menu button 180 is pressed, various settable menu screens are displayed on the display unit 107. The user can make various settings by using the menu screen displayed on the display unit 107, the cross key 174, and the SET button 175.

FIG. 2 is a block diagram showing a configuration example of the digital camera 100 according to the present embodiment. In the present embodiment, the digital camera 100 is interchangeably mounted with a lens unit 200 on which a photographing lens is mounted.

The lens unit 200 includes an aperture 201, an aperture drive circuit 202, an AF drive circuit 203, a lens system control circuit 204, a lens 205, and a communication terminal 206. The lens system control circuit 204 controls each block of the lens unit 200 to realize lens control. For example, the aperture 201 is controlled via the aperture drive circuit 202, and the lens 205 is displaced via the AF drive circuit 203 to focus. The lens 205 is usually composed of a plurality of lenses such as a zoom lens and a focus lens, but here, it is simply shown by only one lens. The communication terminal 206 is a communication terminal for the lens unit 200 to communicate with the digital camera 100, and communicates with the system control unit 250 via the communication terminal 101 described above. The lens unit 200 may be tied to the digital camera 100.

The shutter 207 is a focal plane shutter capable of controlling the exposure time of the imaging unit 208 by driving the shutter 207 in response to the control of the system control unit 250 described later.

The image pickup unit 208 is an image pickup device composed of a CCD, CMOS, or the like that converts an optical image of a subject incident through the lens unit 200 into an electric signal.

The A / D converter 209 converts the analog signal output from the imaging unit 208 into a digital signal.

The memory control unit 210 controls data transmission / reception between the A / D converter 209, the image processing unit 211 described later, and the memory 214. The output data from the A / D converter 209 is written directly to the memory 214 via the image processing unit 211 and the memory control unit 210, or directly via the memory control unit 210.

The image processing unit 211 performs resizing processing such as predetermined pixel interpolation or reduction or color conversion on the output data (image data) from the A / D converter 209 or the image data transmitted / received by the memory control unit 210. Perform image processing such as processing. Further, the image processing unit 211 performs a predetermined calculation process using the captured image data output from the image capturing unit 208 via the A / D converter 209. Based on the obtained calculation result, the system control unit 250, which will be described later, controls each block related to imaging such as the lens system control circuit 204, the shutter 207, and the imaging unit 208 to perform exposure control and distance measurement control. As a result, imaging control such as TTL (through-the-lens) AF (autofocus) processing, AE (autoexposure) processing, and EF (flash pre-flash) processing is performed. The image processing unit 211 further performs a predetermined calculation process using the captured image data, and performs image processing such as a TTL method AWB (auto white balance) process based on the obtained calculation result.

The D / A converter 212 converts the digital signal output from the memory control unit 210 into an analog signal for display.

The display unit 107 and the EVF 213 are composed of an LCD, an organic EL, or the like, and display according to the output data output from the memory control unit 210 and converted by the D / A converter 212. The live view display is realized by sequentially transferring the image data acquired via the lens unit 200 and the imaging unit 208 to the display unit 107 or the EVF 213 for display. Hereinafter, the image displayed in the live view will be referred to as a live view image.

The memory 214 stores the image data obtained by the imaging unit 208 and converted into digital data by the A / D converter 209, and the image data to be displayed on the display unit 107 and the EVF 213. The memory 214 has a storage capacity sufficient to store a predetermined number of still images, moving images for a predetermined time, and audio. Further, the memory 214 also serves as a memory (video memory) for displaying an image. The display image data written in the memory 214 is displayed by the display unit 107 and the EVF 213 via the memory control unit 210.

The operation unit 70 is various operation members as an input unit that receives an operation from the user. The operation unit 70 includes operation members related to shooting instructions such as a shutter button 105, a moving image button 176, and an AE lock button 177. Further, operating members for changing settings such as a main electronic dial 171, a sub electronic dial 173, a cross key 174, a SET button 175, and a menu button 180 may be included. In addition, the touch panel 170a, the power switch 172, the enlargement button 178, the play button 179, and the like are also included in the operation unit 70 in the present embodiment.

The touch panel 170a and the display unit 107 can be integrally configured. For example, the touch panel 170a is configured so that the light transmittance does not interfere with the display of the display unit 107, and is attached to the upper layer of the display surface of the display unit 107. Then, the input coordinates on the touch panel 170a are associated with the display coordinates on the display screen of the display unit 107. As a result, it is possible to provide a GUI (graphical user interface) as if the user directly operates the screen displayed on the display unit 107.

In addition to the operation unit 70, the mode changeover switch 104, the first shutter switch 105a, and the second shutter switch 105b are also operation input means capable of inputting various operation instructions to the system control unit 250 described later. The mode changeover switch 104 switches the operation mode of the system control unit 250 to any one of a plurality of modes such as a still image shooting mode and a moving image shooting mode. The modes included in the still image shooting mode include an auto shooting mode, an auto scene discrimination mode, a manual mode, an aperture priority mode (Av mode), a shutter speed priority mode (Tv mode), a program AE mode (P mode), and the like. In addition, there are various scene modes, custom modes, etc. that are shooting settings for each shooting scene. The mode selector switch 104 allows the user to switch directly to any of these modes. Alternatively, after switching to the shooting mode list screen once with the mode changeover switch 104, one of the displayed plurality of modes may be selected and switched using another operating member. Similarly, the moving image shooting mode may include a plurality of modes.

The first shutter switch 105a is a switch that is turned on by a so-called half-press during operation of the shutter button 105 provided on the digital camera 100, and generates a first shutter switch signal SW1 (shooting preparation instruction). The first shutter switch signal SW1 starts shooting preparation operations such as AF (autofocus) processing, AE (autoexposure) processing, AWB (auto white balance) processing, and EF (flash pre-flash) processing.

The second shutter switch 105b is a switch that is turned on when the operation of the shutter button 105 is completed, so-called fully pressed, and generates the second shutter switch signal SW2 (shooting instruction). The system control unit 250 starts a series of shooting processes until the signal is read from the image pickup unit 208 and the captured image is written as an image file on the recording medium 260 in response to the second shutter switch signal SW2.

The power supply unit 215 includes a primary battery such as an alkaline battery and a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, and a lithium ion battery, an AC adapter, and the like.

The power supply control unit 216 is composed of a battery detection circuit, a DC-DC converter, a switch circuit for switching a block to be energized, and the like, and detects whether or not a battery is installed, the type of battery, and the remaining battery level. Based on the detection result and the instruction of the system control unit 250, the power supply control unit 216 controls the DC-DC converter and supplies the required voltage to each unit including the recording medium 260 for a necessary period.

The out-of-viewfinder display unit 103 displays various settings of the camera, such as the shutter speed and the aperture, via the out-of-viewfinder display unit drive circuit 218.

The non-volatile memory 219 is a memory that can be electrically erased and recorded, and for example, a Flash-ROM or the like is used. The non-volatile memory 219 stores constants, programs, and the like for the operation of the system control unit 250. The program referred to here is a program for executing various flowcharts described later in the present embodiment.

The system control unit 250 is a control unit including at least one processor or circuit, and controls the entire digital camera 100. By executing the program recorded in the non-volatile memory 219 described above, each process of the present embodiment described later is realized.

In the present embodiment, a plurality of temperature sensors for acquiring the temperature of a predetermined location are provided. The exterior temperature sensor 220a, the imaging unit temperature sensor 220b, and the system control unit temperature sensor 220c are, for example, digital temperature sensors incorporating an A / D converter (not shown). The temperature measurement value of each temperature sensor is converted into a temperature value in degrees Celsius inside the sensor, and then taken into the system control unit 250 by serial communication at regular intervals.

The arrangement of each temperature sensor according to the present embodiment will be described with reference to FIG. FIG. 3 shows an outline of each arrangement example of the exterior portion temperature sensor 220a, the imaging unit temperature sensor 220b, and the system control unit temperature sensor 220c inside the housing when the digital camera 100 is viewed from the rear side.

The exterior temperature sensor 220a is intended to monitor the housing exterior temperature of the digital camera 100, and is arranged near the exterior inside the housing and away from the imaging unit 208 or the system control unit 250. ..

The image pickup unit temperature sensor 220b is arranged on the same substrate as the peripheral portion in the vicinity of the image pickup unit 208, for example, the image pickup sensor mounting substrate of the image pickup unit 208 for the purpose of temperature monitoring of the image pickup unit 208.

The system control unit temperature sensor 220c is intended for temperature monitoring of the system control unit 250, and is arranged on the same substrate as the peripheral portion near the system control unit 250, for example, the mounting substrate of the system control unit 250.

The eyepiece detection unit 109 is an eyepiece detection sensor that detects the approach (eyepiece) and detachment (eyepiece) of the eye (object) to the eyepiece 108 of the finder (approach detection). The system control unit 250 switches the display (display state) / non-display (non-display state) of the display unit 107 and the EVF 213 according to the state detected by the eyepiece detection unit 109. More specifically, at least in the shooting standby state and when the display destination is automatically switched, the display unit 107 is turned on during non-eye contact to display, and the EVF 213 is hidden. Further, during the eyepiece, EVF213 is turned on for display, and the display unit 107 is hidden.

The eyepiece detection unit 109 uses, for example, an infrared proximity sensor to detect the approach of some object to the eyepiece unit 108 of the finder incorporating the EVF 213. When an object approaches, the infrared rays projected from the light projecting unit (not shown) of the eyepiece detection unit 109 are reflected and received by the light receiving unit (not shown) of the infrared proximity sensor. From the amount of infrared rays received, it is possible to determine how close the object is from the eyepiece portion 108 (eyepiece distance). In this way, the eyepiece detection unit 109 detects the close distance of the object to the eyepiece unit 108.

When an object approaching the eyepiece portion 108 within a predetermined distance is detected from the non-eyepiece state (non-approaching state), it is assumed that the eyepiece is detected. When the object that has detected the approach is separated by a predetermined distance or more from the eyepiece state (approaching state), it is assumed that the eye has been removed. The threshold value for detecting the eyepiece and the threshold value for detecting the eyepiece may be different, for example, by providing hysteresis. In addition, after the eyepiece is detected, the eyepiece is assumed to be in the eyepiece state until the eyepiece is detected. After the eyepiece is detected, it is assumed that the eyepiece is not in the eyepiece state until the eyepiece is detected. The infrared proximity sensor is an example, and the eyepiece detection unit 109 may employ another sensor as long as it can detect the approach of an eye or an object that can be regarded as an eyepiece.

The posture detection unit 221 detects the posture of the digital camera 100 with respect to the direction of gravity. Based on the posture detected by the posture detection unit 221, whether the image taken by the image pickup unit 208 is an image taken by holding the digital camera 100 horizontally or an image taken by holding the digital camera 100 vertically. Can be determined. The system control unit 250 can add orientation information according to the posture detected by the posture detection unit 221 to the image file of the image captured by the image pickup unit 208, or rotate and record the image. be. As the posture detection unit 221, an acceleration sensor, a gyro sensor, or the like can be used. It is also possible to detect the movement (pan, tilt, lift, whether or not it is stationary, etc.) of the digital camera 100 by using the posture detection unit 221 such as an acceleration sensor or a gyro sensor.

The communication unit 222 is connected by a wireless or wired cable to transmit and receive video signals and audio signals. The communication unit 222 can be connected to a wireless LAN (Local Area Network) and the Internet, and can also communicate with an external device using Bluetooth (registered trademark) or Bluetooth Low Energy. The communication unit 222 can transmit an image (including a live view image) captured by the imaging unit 208 and an image recorded on the recording medium 260, and also receives an image and various other information from an external device. Can be done.

The system timer 223 is a time measuring unit that measures the time used for various controls and the time of the built-in clock.

For example, a RAM is used in the system memory 224, and constants and variables for operation of the system control unit 250, a program read from the non-volatile memory 219, and the like are developed.

The recording medium I / F 225 is an interface with a recording medium 260 such as a memory card or a hard disk.

The recording medium 260 is a recording medium such as a memory card for recording a captured image, and is composed of a semiconductor memory, a magnetic disk, or the like. In this embodiment, the recording medium 260 has a configuration that can be attached to and detached from the digital camera 100.

The digital camera 100 of the present embodiment is controlled so as to limit its operation so that the temperature related to the digital camera 100, such as the exterior temperature, the image pickup unit temperature, and the system control unit temperature, becomes a predetermined temperature condition. .. For example, during the operation of the digital camera 100, electronic devices such as the image pickup unit 208, the communication unit 222, the image processing unit 211, and the system control unit 250 serve as heat sources, and the temperature inside the housing rises. For example, an increase in the temperature of the imaging unit 208 causes deterioration of the captured image. Therefore, each electronic device is provided with an upper limit temperature at which operation can be guaranteed, and it is necessary to limit the operation so as not to exceed the upper limit temperature.

In addition, since various electronic devices are mounted in a small housing, the exterior of the housing also generates heat during operation. Since the exterior of the housing is a part that the user directly touches, an allowable temperature is provided so that the user does not touch it because it is too hot, and it is necessary to limit the operation so that the temperature is lower than the allowable temperature.

Here, as an operation limitation, the power of the digital camera 100 is turned off. Even if the power is not turned off, even if it is an operation restriction for stopping or reducing the operation of the part related to the allowable temperature, for example, stopping the recording of the moving image, stopping the imaging or lowering the frame rate, turning off the display, etc. Just do it.

Here, with reference to FIG. 4, the change of the output value of each temperature sensor with time when the digital camera 100 is set to the moving image shooting mode will be described. Hereinafter, in FIG. 4A, the horizontal axis represents time and the vertical axis represents temperature, and in FIGS. 4B to 4D, the horizontal axis represents time and the vertical axis represents temperature.

FIG. 4A shows an example of the output value of the imaging unit temperature sensor 220b and the output value of the exterior unit temperature sensor 220a when the operation of recording the moving image and the recording standby operation is started at the same time and the same temperature. There is. The curve 401 shows the time-dependent change in the output value of the image pickup unit temperature sensor 220b during moving image recording, and the curve 402 shows the hourly change in the output value of the exterior portion temperature sensor 220a during moving image recording. The curve 403 shows the time-dependent change of the output value of the image pickup unit temperature sensor 220b during the moving image standby, and the curve 404 shows the hourly change of the output value of the exterior portion temperature sensor 220a during the moving image standby. Curve 401 to 404, from the output values of each temperature sensor indicates a value obtained by subtracting the ambient temperature K _E, the initial temperature is assumed to be 0 ° C..

The relational expression at this time is shown in Equation 1.

[Number 1]
y = f ₄₀₁ (t): Relational expression showing curve 401 y = f ₄₀₂ (t): Relational expression showing curve 402 y = f ₄₀₃ (t): Relational expression showing curve 403 y = f ₄₀₄ (t): relationship diagram showing a curve 404 4 (b) is in the standby state before movie shooting to time t _S, when starting the video recording from the time t _S, the time variation of each of the output values of each temperature sensor Shown. Output value of the imaging unit temperature sensor 220b until the time t _S along a curve 403 showing the temperature change of the standby state changes, from the time t _S varies along the curve 401 showing the temperature change during moving image recording. Since the temperature changes along the curve 403 in the standby state before recording the moving image, and the temperature changes along the curve 401 from the state where the temperature reaches y _{DC at time t S, FIG. 4 (b) shows FIG.} The curve 401 of a) is shifted to the temperature y _{DC at time t S.} Similarly, the output value of the exterior portion temperature sensor 220a is changed along the time _{t S} to curve 404, from the time _{t S} varies along the curve 402. In FIG. 4 (b), curves 401 and curve 402, the temperature of 0 ℃ at time _{t O.}

Here, assuming that the time _{from time t O} to t _S is time t _C , the relational expression of the curve shown in FIG. 4 (b) is given as shown in Equation 2.

[Number 2]
y _DC = f ₄₀₃ (t _S ) = f ₄₀₁ (t _S −t _O ) = f ₄₀₁ (t _C )
y _OC = f ₄₀₄ (t _S ) = f ₄₀₂ (t _S −t _O ) = f ₄₀₂ (t _C )
Number 2 indicates that the output value y _DC imaging unit temperature sensor 220b at time t _S in the recording standby video matches the output value of the imaging unit temperature sensor 220b after time t _C during video recording ing. Similarly, it is shown that the output value y _OC of the exterior temperature sensor 220a matches the output value of the exterior temperature sensor 220a after a _{time t C} during moving image recording.

Therefore, as shown in Equation 3, the time t _C can be predicted during the video standby from the inverse function of Equation 1 described above.

[Number 3]
t _C = f ₄₀₁ ^-1 (y _DC )
t _C = f ₄₀₂ ^-1 (y _OC )
FIG. 4 (c) shifts the curves 401 and 402 of FIG. 4 (b) in the time axis direction so _{that the origin is at time t O, and time t S} = time t _O + time t _C. .. _{From Equation 4, the time t DL at} which the recording of the moving image is stopped can be predicted based on the temperature of the image pickup unit temperature sensor 220b. At this time, for example, K _DL is the operation guaranteed temperature of the imaging unit 208 for outputting an image without image deterioration (acceptable), and the time not exceeding this operation guaranteed temperature is the moving image recording stop time t _DL . Become.

Similarly, based on the temperature of the exterior portion temperature sensor 220a, it is possible to predict the recording stop time t _OL video. The _KOL is based on, for example, the permissible temperature of the exterior that can be tolerated when the user touches it, and the time that does not exceed this permissible temperature is the moving image recording stop time _tOL . That shows the number 4, K _DL is moving stop temperature based on the temperature of the imaging unit temperature sensor 220b, the K _OL temperatures recorded video based on the temperature of the exterior portion temperature sensor 220a is stopped

[Number 4]
t _DL = f ₄₀₁ ^-1 (K _DL )
t _OL = f ₄₀₂ ^-1 ( _KOL )
_{Using the time t C} calculated by Eq. 3, from Eq. 5, predict _{the moving image recordable time t DR based} on the image pickup unit temperature sensor 220b when it is assumed that the moving image recording is started at _{the time t S} during the moving image standby. be able to. Similarly, the moving image recordable time t _OR of the exterior temperature sensor 220a can be predicted. In Equation 5, t _DR indicates a moving image recordable time based on the temperature of the imaging unit temperature sensor 220b, and t _OR indicates a moving image recording time based on the temperature of the exterior temperature sensor 220a.

[Number 5]
t _DR = t _DL −t _C
t _OR = t _OL −t _C
Here, the number 1 from the output value of the temperature sensor indicates a value a housing surrounding environment temperature K _E by subtracting the digital camera 100, in this embodiment, the number mentioned above 1-5 environmental temperature K _It holds only when E is 0 ° C. However, the actual output values of each temperature sensor is dependent on the environmental temperature K _E, varies according to the value of K _E.

Therefore, the relational expression of equation 6 is defined.

[Number 6]
y = h ₄₀₅ (t) = f ₄₀₁ (t) -f ₄₀₂ (t)
Equation 6 is a function representing the difference between the curve 401 and the curve 402. The curve 405 of FIG. 4C is a curve represented by the relational expression of Equation 6. 6 is different from the number 1, it does not depend on the environmental temperature K _E. The temperature difference ΔK between the curve 401 and the curve 402 after the lapse of time t _{C (time t s) is uniquely determined.} Therefore, if the temperature output difference between the image pickup unit temperature sensor 220b and the exterior portion temperature sensor 220a can be acquired, the time t _C can be obtained using Equation 6.

This will be described with reference to FIG. 4 (d). FIG. 4 (d), the curves 401 and curve 402 of FIG. 4 (c), is obtained by environmental temperature _{K E} shifts in temperature axis. At this time, the relational expression of equation 7 holds.

[Number 7]
t _C = h ₄₀₅ ^-1 (ΔK)
ΔK = K _DC- K _{OC
K DC = y DC + K E} : imaging unit temperature sensor 220b of the output values _{K OC = y OC + K E} : output value of the exterior portion temperature sensor 220a also based on any relationship of 1, for example, the number 8 Accordingly, it is possible to determine the environmental temperature K _E. Equation 8 is an example using a relational expression showing the curve 402 of Equation 1.

[Number 8]
_{K E = K OC -y OC =} K OC -f 402 (t C)
From the above, the number 4 can be rewritten to the number 9.

[Number 9]
^{_{t DL = f 401 -1 (K}} DL -K E)
^{_{t OL = f 402 -1 (K}} OL -K E)
By substituting the equation 9 into the equation 5, the moving image recordable time based on the temperature of each temperature sensor can be predicted.

The image pickup unit temperature sensor 220b and the exterior portion temperature sensor 220a have been described above as examples. By replacing the image pickup unit temperature sensor 220b with the system control unit temperature sensor 220c, it is possible to predict the moving image recordable time until the system control unit 250 reaches the upper limit temperature at which operation can be guaranteed.

In any case, it is preferable to use the output difference value between the temperature sensor installed near the electronic device serving as the heat source and the temperature sensor installed near the exterior of the housing which is not easily affected by the heat generated by the device. By the output difference value between the temperature sensor increases, improved prediction accuracy of the time t _C in Equation 7, as a result, the prediction accuracy of the environmental temperature K _E in Equation 8, and the temperature of each temperature sensor in the number 5 The accuracy of predicting the video recordable time based on is improved.

Hereinafter, with reference to FIG. 5, a method of predicting and displaying the operable time (moving image recordable time) of the digital camera 100 according to the embodiment of the present invention will be described.

FIG. 5 is a flowchart for controlling the prediction processing of the operable time of the digital camera 100 according to the embodiment of the present invention. Each process in the flowchart of FIG. 5 is realized by the system control unit 250 expanding the program stored in the non-volatile memory 219 into the system memory 224, executing the program, and controlling each functional block. The flowchart of FIG. 5 starts from the place where the digital camera 100 is activated and the moving image shooting mode is set to the moving image standby state.

In step S501, at the current time _{t S} in the moving stand, the output value _{K OC} of the output values _{K DC} and exterior temperature sensor 220a of the image pickup unit temperature sensor 220b the system control unit 250 obtains.

In step S502, the difference value ΔK between the _{output value K DC} of the imaging unit temperature sensor 220b _{and the output value K OC} of the exterior unit temperature sensor 220a is calculated.

In step S503, it is determined whether or not _{ΔK is larger than the predetermined threshold value ΔK TH.} If ΔK is _{larger than ΔK TH} , the process proceeds to step S504. If ΔK is ΔK _TH or less, the process returns to step S501. If ΔK, which is the difference between the output values of the image pickup unit temperature sensor 220b and the exterior portion temperature sensor 220a, is too small, the accuracy of estimating the _{time t C} will decrease. Therefore, step S501 until ΔK becomes larger than the _{threshold value ΔK TH.} Repeat 502. The threshold value ΔK _TH is a set value preset so that the accuracy of estimating the _{time t C} is acceptable from, for example, an experimental value. The threshold value ΔK _TH is stored in the non-volatile memory 219 in advance and is read out by the system control unit 250.

_{In step S504, the moving image recording time t C} corresponding to the difference value ΔK calculated in step S503 is calculated. A relational expression (temperature curve information) of the number 7 different for each of a plurality of moving image recording modes is stored in advance in the non-volatile memory 219, and the system control unit 250 has a relational expression of the number 7 corresponding to the moving image recording mode in use. Is read out and t _C is calculated.

In step S505, it calculates the environmental temperature _{K E} from the moving image recording time _{t C} calculated in step S504. Relationship of a plurality of moving image recording mode every different number 8 is stored in the nonvolatile memory 219, the system controller 50 reads the relational expression number 8 corresponding to the moving image recording mode in use K _E Is calculated.

In step S506, _{K E} is equal to or greater than a predetermined threshold _{K TH.} K _E moves to step S507 is larger than _{K TH.} If _KE is K _TH or less, the process proceeds to step S514. The threshold value _KTH is stored in advance in the non-volatile memory 219, and is read out by the system control unit 250. Here, the threshold value _KTH means an ambient temperature at which the temperature inside the housing of the digital camera 100 does not reach the upper limit temperature at which the digital camera 100 can operate under the ambient temperature. By inserting this determination, in a situation that there is no possible environmental temperature K _E reaches the operational upper limit temperature below the threshold value K _TH, it is possible to skip the unnecessary arithmetic processing, is possible to reduce the CPU load can.

In steps S507 and S508, the moving image stop time t _{DL based on the temperature of the imaging unit temperature sensor 220b and the moving image stop time t OL} based on the temperature of the exterior part temperature sensor 220a are calculated based on the relational expression of Equation 4. A relational expression (temperature curve information) of the number 4 different for each of a plurality of moving image recording modes is stored in advance in the non-volatile memory 219, and the system control unit 250 has a relationship of the number 4 corresponding to the moving image recording mode in use. Read the formula.

In steps S509 and S510, the moving image recordable time t _DR based on the imaging unit temperature sensor 220b and the moving image recordable time t _OR of the exterior temperature sensor 220a are calculated based on the relational expression of Equation 5.

In step S511, it is determined whether or not _{t DR} is _{smaller than t OR.} If t _DR is _{smaller than t OR} , the process proceeds to step S512. If t _DR is t _OR or more, the process proceeds to step S513.

In step S512, the system control unit 250, the display unit 107 or EVF213, displaying the _{t DR} as video recordable time.

In step S513, that is, when t _DR is t _{OR or more, the system control unit 250 displays t OR} as the moving image recordable time on the display unit 107 or EVF 213.

In step S514, i.e., when _{K E} is less than _{K TH,} the system control unit 250 causes the display unit 107 or EVF213, does not display the moving image recordable time.

Next, with reference to FIG. 6, a method of displaying the moving image recordable time on the display unit 107 or the EVF 213, which is carried out in steps S512 and S513, will be described. FIG. 6 is an example of the display screen of the digital camera 100 according to the embodiment of the present invention, and shows an example of displaying the moving image recordable time on the display unit 107 or the EVF 213 in the moving image standby state. The image data captured by the imaging unit 208 is sequentially transferred to the display unit 107 or EVF 213 and displayed in a live view. Various shooting parameters are superimposed and displayed on the live view image.

The time 601 indicates a moving image recording possible time until the digital camera 100 reaches the temperature limit when the moving image recording is started at the current time. If the state of waiting for the moving image continues, the temperature inside the housing of the digital camera 100 rises, so that the moving image recordable time displayed as the time 601 gradually decreases. When the video recording possible time is less than the recording time expected by the user, the user can take measures such as stopping the imaging operation of the digital camera 100. By stopping the imaging operation, the heat generation of the imaging unit 208 and the system control unit 250 can be suppressed, so that the moving image recording time can be recovered.

The embodiment according to the present invention has been described above. The system control unit 250 may be controlled by one hardware, or the entire device may be controlled by sharing the processing among a plurality of hardware.

According to the present embodiment, it is possible to predict the video recordable time when it is assumed that the video recording is started during the video standby, and display the video recordable time on the display unit 107 or the EVF 213 of the digital camera 100. can. Before starting the moving image recording, the user can start the moving image recording after confirming whether or not the desired moving image recording possible time is satisfied, so that the convenience is improved.

Further, by using the output difference value ΔK of two different temperature sensors _{of the} output value K _OC of the output values K _DC and the exterior temperature sensor 221a of the image pickup unit temperature sensor 220b, without being affected by variations in environmental temperature K _E In addition, the time t _C can be calculated.

When ΔK calculated in step S502 described above is small, _{it is considered that the prediction accuracy of the time t C} in step S504 is lowered, and as a result, the prediction accuracy of the moving image recordable time is lowered. In the present embodiment, _{by determining whether or not ΔK is larger than the predetermined threshold value ΔK TH} , the moving image recordable time can be displayed only when the prediction accuracy is highly reliable. It is possible to reduce the possibility of providing incorrect information to the user.

In this embodiment, in step S505, according to the structure of this embodiment for calculating the environmental temperature K _E, in an environment where ambient temperature varies, it is possible to improve the prediction accuracy of uptime.

Further, by using the temperature sensor necessary for monitoring the temperature inside the housing of the digital camera 100, it is possible to predict the ambient temperature without additional parts for acquiring the ambient temperature by another means.

(Other embodiments)
In the first embodiment, one but with two different temperature sensors, for example, when used in an environment where ambient temperature K _E is considered to be constant, a temperature sensor located inside the housing of the digital camera 100 May be used to calculate the video recordable time. Since the number of parts can be reduced as compared with the first embodiment, there is a cost merit.

Further, according to the first embodiment, by replacing the imaging unit temperature sensor 220b with the system control unit temperature sensor 220c, it is possible to predict the operable time until the system control unit 250 reaches the upper limit temperature at which the system control unit 250 can operate. can. The type of electronic device that needs to stop moving images differs depending on the type of moving image mode of the digital camera 100. For example, in a high frame rate video mode such as shooting a FullHD video at 240 fps, the power consumption of the imaging unit 208 is higher and more heat is generated as compared with a low frame rate video mode such as shooting a FullHD video at 30 fps. Tend to do. Therefore, it is preferable to use the image pickup unit temperature sensor 220b to predict the moving image recordable time.

On the other hand, in a high-resolution video mode with a low frame rate such as shooting an 8K video at 30 fps, the load of development processing is higher than in a low-resolution video mode such as shooting a FullHD video at 30 fps, and the system The power consumption of the control unit 250 becomes higher. Therefore, it is preferable to use the system control unit temperature sensor 220c to predict the moving image recordable time.

As described above, it is also possible to switch the temperature sensor used for calculating the moving image recordable time according to the type of the moving image mode.

In the first embodiment, the shorter moving image recordable time is displayed among _{the moving image recordable time t DR} based on the temperature of the imaging unit temperature sensor 220b and the moving image recordable time t _{OR of the exterior part temperature sensor 220a.} .. When there are three or more temperature sensors mounted on the digital camera 100, it is possible to compare the lengths of video recordable time based on all temperature sensor standards and display a shorter video recordable time. Is.

In the first embodiment, in step S514, when there is no limit on the video recording time, the video recording time is not displayed. However, for example, an icon indicating that the video recording can be performed indefinitely is displayed. May be good. In addition, shorter video recording is possible by comparing the video recordable time limited by other factors such as card capacity and battery capacity with the video recordable time limited by the temperature rise inside the housing of the digital camera 100. It is also possible to display the time.

In the first embodiment, in FIG. 6, the video recordable time is displayed as the time, but for example, the video recordable time is displayed by a meter display suitable for displaying the time or another icon or the like. May be configured to notify. Any means may be used as long as the display configuration serves the purpose of notifying the video recordable time. In addition, it is also possible to display the moving image recordable time in consideration of the recordable capacity of the recording medium 260 in time 601. When the recordable capacity of the recording medium 260 is smaller than the moving image recordable time based on the temperature limit, the moving image recordable time based on the recordable capacity may be displayed.

Further, as long as the configuration fulfills the purpose of predicting and notifying the operable time for which the operation is restricted due to the temperature condition, the operable time related to another function may be notified regardless of only the moving image recording.

In the first embodiment, the live view display state is set during the moving image standby, but what kind of operating state is used as long as the feature of the present invention that can predict the moving image recording time is not lost before the moving image is recorded. It may be defined as waiting for a video.

The above is a description of a preferred embodiment of the present invention, but the present invention is not limited to the above embodiment within the scope of the technical idea of the present invention, and is appropriately modified and adapted depending on the target circuit form. It should be done. Although the present invention has been described in detail as a preferred embodiment thereof based on a digital camera, the present invention is not limited to these specific embodiments, and various embodiments within the scope of the gist of the present invention are also the present invention. include. Further, the present invention can be applied to any electronic device having a device that generates heat. For example, it can be applied to personal computers, PDAs, mobile phone terminals, wearable devices such as game machines, electronic book readers, and head-mounted displays. In any of the embodiments, according to the present invention, it is possible to predict the moving image recording time limited by the temperature rise inside the housing of the electronic device.

Further, the present invention can be implemented as, for example, a system, a device, a method, a computer program, a recording medium, or the like. Specifically, even if it is realized by one device, it is applied to a system composed of a plurality of devices. You may. Each means constituting the image pickup apparatus and each step of the control method of the image pickup apparatus according to the present embodiment can also be realized by operating a program stored in a memory of a computer or the like. The computer program and a computer-readable recording medium on which the program is recorded are included in the present invention.

The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

100 Digital camera 107 Display unit 213 EVF
250 System control unit 219 Non-volatile memory 220a Exterior temperature sensor 220b Imaging unit temperature sensor 220c System control unit temperature sensor 260 Recording medium

Claims (14)

A temperature sensor that acquires the temperature of a predetermined part of the own device,
A control means that limits the function based on the temperature of the predetermined location, and
Before the function is executed, the function is restricted by the control means based on the current temperature acquired by the temperature sensor and the time-dependent temperature change of the predetermined location when the function is executed. Predictive means to calculate the operable time until it is done,
An imaging device characterized by having. The imaging device according to claim 1, further comprising a display means for displaying the operable time before the function is executed. It has a shooting means for generating and recording a moving image from a subject.
The function is a function of recording the moving image.
The imaging device according to claim 2, wherein the display means displays the operable time as a recordable time of a moving image. The imaging apparatus according to any one of claims 1 to 3, further comprising a storage means that previously stores information regarding a temperature change at a predetermined location when the function is executed. The fourth aspect of claim 4, wherein the information regarding the temperature change at the predetermined location when the function is executed is stored as the temperature curve information regarding the temperature acquired by the temperature sensor at predetermined time intervals. Imaging device. The temperature sensor is a plurality of temperature sensors that acquire temperatures at a plurality of different locations.
Any of claims 1 to 5, wherein the prediction means further calculates the operable time based on a difference value of current temperatures of the plurality of different locations acquired by the plurality of temperature sensors. The image pickup apparatus according to item 1. The imaging device according to claim 6, wherein the temperature curve information includes temperature curve information relating to a temperature difference value at predetermined time intervals by the plurality of temperature sensors. The shooting means has a plurality of moving image modes for shooting the moving image, and has a plurality of moving image modes.
The method according to any one of claims 4 to 7, wherein the information regarding the temperature change at the predetermined location when the function stored in the storage means in advance is executed is different for each of the moving image modes. Imaging device. The imaging device according to any one of claims 1 to 8, wherein the prediction means does not execute the calculation of the operable time when the temperature acquired by the temperature sensor is equal to or lower than a predetermined temperature. .. The imaging device according to any one of claims 6 to 9, wherein the display means displays a shorter time among a plurality of operable times corresponding to the plurality of temperature sensors. An image sensor that acquires the subject and
It has a system control unit that controls its own device,
The temperature sensor is arranged at at least one of a position where the temperature of the exterior temperature of the own device can be acquired, a position where the temperature of the image sensor can be acquired, and a position where the temperature of the system control unit can be acquired. The image pickup apparatus according to any one of claims 1 to 10, wherein the image pickup apparatus is characterized by the above. A temperature sensor that acquires the temperature of a predetermined part of the image pickup device, and
A control method for an image pickup apparatus having a control means for limiting a function based on a temperature at a predetermined location.
Before the function is executed, until the function is restricted by the control means based on the current temperature acquired by the temperature sensor and the information on the temperature change at the predetermined location when the function is executed. Steps to calculate the operable time of
A control method characterized by that. The control method according to claim 12, further comprising a step of displaying the operable time before the function is executed. It has a step of generating and recording a moving image from a subject,
The function is a function of recording the moving image.
The control method according to claim 13, wherein in the display step, the operable time is displayed as a recordable time of a moving image.

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