JP2009177564A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress flickering of a display image caused by light source flicker which are the flickers of illumination light for illuminating an object, when displaying a moving picture, while photographing the object by an imaging device. <P>SOLUTION: A display flicker reduction processing part 108 can perform display flicker reduction processing by a plurality of display flicker reduction processing methods, corresponding to different light source flicker frequencies, in order to reduce display flickers produced in the moving picture displayed on an image display part 116 due to light source flicker. An environmental light detecting part 124 detects the brightness or the color components of light of the object or light surrounding the object. A power supply frequency determining part 122a determines the power supply frequency of a commercial power supply supplied to the environments where the image pickup device is located. Based on the detected result of the brightness or the color components of light of the object or light surrounding the object and the result of the power supply frequency determined by the power supply frequency determining part, a display flicker reduction processing method to be executed by the display flicker reduction processing part 108 by the environmental light detecting part 124 is selected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and can reduce display flicker that occurs when a subject is illuminated with an illumination light source that periodically blinks, such as a fluorescent lamp, and a moving image is displayed on a display device. The present invention relates to an imaging apparatus.

  Monitor displayed during shooting when shooting a subject under illumination with a light source that repeatedly blinks at a frequency twice that of the power supply frequency, such as a non-inverter fluorescent lamp that emits light from commercial AC power It is known that images or playback images appear to flicker. Further, in a digital still camera, a through image (live view) displayed on a display device during shooting may be affected by flickering of illumination light and may flicker. The above-described flickering of the illumination light source and flickering resulting from shooting under the flickering illumination light source are also referred to as flicker. In the present specification, when it is necessary to distinguish between these, the flickering of the illumination light source is referred to as light source flicker, and the flicker that occurs on the display screen of the imaging apparatus is referred to as display flicker.

  In order to effectively reduce display flicker, it is necessary to reliably detect the presence or absence of light source flicker and the frequency of light source flicker, and to perform display flicker reduction processing corresponding to the detected light source flicker frequency.

  Techniques for detecting the presence or absence of light source flicker include those disclosed in Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5.

  Japanese Patent Application Laid-Open No. H10-260260 discloses a technique for storing image data for several frames and detecting a light source flicker from a difference (change) in luminance value of each frame. Japanese Patent Application Laid-Open No. H10-228688 discloses a technique for storing image data for several frames, performing frequency analysis based on the image data, and specifying the frequency of the light source flicker.

  Japanese Patent Application Laid-Open No. H10-228667 discloses a method for estimating the frequency of light source flicker by comparing two types of images obtained by photographing under different shutter conditions. Patent Document 4 discloses a ratio of outputs from a plurality of light receiving elements having different spectral sensitivities as well as detecting the presence or absence of flicker of a light source based on the change in photometric output at a predetermined time. A technique for estimating the type of light source (incandescent lamp, fluorescent lamp) based on the above is disclosed.

Patent Document 5 discloses whether ambient light is fluorescent light, tungsten light, or natural light based on a ratio of output signals from color information detection sensors having spectral sensitivity in the R region, B region, and G region. What makes a determination is disclosed.
JP 2006-319831 A JP 2004-222228 A Japanese Unexamined Patent Publication No. 2000-165752 JP-A-7-230121 Japanese Patent Laid-Open No. 7-114092

  Among the techniques related to the above-described light source flicker detection, those disclosed in Patent Documents 1 to 3 require a frame memory for storing several frames of image data. Further, when the field luminance is low, it may be impossible to accurately determine the presence or absence of light source flicker. Although what is disclosed in Patent Document 4 detects the presence or absence of flicker, there is no disclosure regarding detection of the flicker frequency. In the one disclosed in Patent Document 5, it is necessary to separately provide a color information detection sensor, which may cause an increase in cost.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to realize a technique capable of accurately detecting the presence / absence of flicker and the flicker cycle even in a low luminance situation.

(1) The present invention is applied to an imaging apparatus capable of displaying a moving image on an image display unit based on image signals sequentially read from an imaging element. In order to reduce display flicker caused by light source flicker in the moving image displayed on the image display unit, any one of the light source flicker reduction methods provided among a plurality of display flicker reduction processing methods corresponding to different light source flicker frequencies is provided. A display flicker reduction processing unit configured to be able to perform the display flicker reduction processing using a display flicker reduction processing method corresponding to the above, and ambient light detection for detecting the brightness or color component of the light surrounding the subject A power frequency determining unit that determines a power frequency of a commercial power source that is supplied to an environment in which the imaging apparatus exists, and a detection result of brightness or color components of light surrounding the subject by the environmental light detecting unit, Based on the determination result of the power supply frequency by the power supply frequency determination unit, the display flicker to be executed by the display flicker reduction processing unit. By having a display flicker reduction process method selecting unit for selecting Tsu mosquitoes reduction processing method, to solve the problems described above.

  According to the present invention, in order to reduce display flicker caused by light source flicker in a moving image displayed on the image display unit, among a plurality of display flicker reduction processing methods provided in advance corresponding to different light source flicker frequencies. Display flicker reduction processing to be executed by the display flicker reduction processing unit based on the detection result of the brightness or color component of the light surrounding the subject by the ambient light detection unit and the determination result of the power supply frequency by the power supply frequency determination unit By having a configuration for selecting a method, it is possible to effectively suppress display flicker caused by the light surrounding the subject having flicker regardless of the frequency of the power source that supplies power to the light source. .

  FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention. The imaging apparatus 100 includes a photographing lens 102, an imaging element 104, an image signal processing unit 112, a timing generation unit 114, an image display unit 116, a memory control unit 118, a memory 120, a CPU 122, an interface 126, and the like. A storage medium 128, a system bus 130, and a display flicker reduction processing method setting unit 132. The image signal processing unit 112 includes a synchronization processing unit 106, a display flicker reduction processing unit 108, an image processing unit 110, and an ambient light detection unit 124.

  The taking lens 102 forms a subject image on the image pickup surface of the image pickup element 104 constituted by a CCD or CMOS image sensor. In the present specification, the image sensor 104 is described as a CMOS image sensor having processing blocks such as CDS and A / D conversion therein and capable of outputting digital image signals. As the image sensor 104, an image sensor capable of outputting RGB, YCM, and other primary color image signals, or an image sensor capable of outputting an image signal having a number of primary colors larger than three can be used. In the present embodiment, description will be made assuming that image signals of the RGB three primary colors can be output.

  A digital image signal output from the image sensor 104 is temporarily stored in the memory 120 via the memory control unit 118. Since the memory 120 is also used as a buffer memory when the image signal processing unit 112 performs image processing, it is desirable that the writing / reading speed be fast, and it can be constituted by, for example, a DRAM. The imaging device 104, the image signal processing unit 112, the CPU 122, and the image display unit 116 are configured to be accessible to the memory 120 via the system bus 130. The memory control unit 118 has a function of arbitrating memory access requests from the above-described components.

  The image signal processing unit 112 can be configured by an application specific integrated circuit (ASIC) or the like. This image signal processing unit 112 is synchronized with a digital image signal output from the image sensor 104 and temporarily stored in the memory 120 (demosaic processing), white balance adjustment, gradation / level correction, unsharp mask, In addition to generating digital image data by performing processing such as shading correction, processing including the following three processings can be executed. That is, one is processing (through image display processing) for generating a through image and displaying it on the image display unit 116 at the time of shooting. The other is processing (image recording processing) for generating image data for recording based on the image signal read from the image sensor 104 and recording it. The other is processing (reproduction display processing) of reading the recorded image data and displaying an image based on the image data on the image display unit 116. In the through image display process, a display flicker reduction process, which will be described in detail later, is executed by the display flicker reduction processing unit 108 as necessary. The ambient light detection unit 124, based on the RGB three primary color image signals generated by the synchronization processing unit 106, the subject or light surrounding the subject (hereinafter referred to as “ambient light” in this specification). The brightness or color component can be detected.

  When the image signal processing unit 112 performs image recording processing, the image data generated by the image signal processing unit 112 is JPEG-compressed as necessary and recorded in the storage medium 128 via the interface 126. Various storage media 128 can be used. As an example, the storage medium 128 can be configured by a flash memory, and may be built in the imaging apparatus 100 or detachable from the imaging apparatus 100.

  The image display unit 116 includes a display element 116D configured by a color liquid crystal display (LCD) panel or an organic EL (OEL) display panel, and an image corresponding to the content of the above-described processing of the image signal processing unit 112. And a display control unit 116C that performs a process of displaying on the screen. The display element 116 </ b> D may be an EVF (= Electronic View Finder) that looks at an image displayed on a small display panel through a magnifying optical system, or is provided on the back surface or side surface of the imaging device 100. It may be a monitor display panel. Alternatively, both the EVF and the monitor display panel may be provided so that the photographer can select which one to use.

  The CPU 122 has a function of generally controlling the operation of the imaging apparatus 100 as a whole. For example, a series of operations such as photometry related to automatic exposure, exposure amount calculation, charging of the main capacitor for the flash unit, adjustment of the light emission amount of the flash, zoom driving of the photographing lens 102, focusing, acceptance of the photographing mode setting operation by the photographer Control signals are sent to the image display unit 116, the shutter (not shown) is opened and closed, the aperture (not shown) is controlled. The CPU 122 also has a function for overall control of the operation of the image signal processing unit, and instructs the image processing unit 110 to perform any of the above-described through image display processing, image recording processing, and reproduction display processing. To emit. The display flicker reduction process described later is also executed by the image signal processing unit 112 based on a command from the CPU 122. The CPU 122 further includes a power frequency determination unit 122a and a display flicker reduction processing method selection unit 122b.

  By the way, the display flicker periodically captures images (charge accumulation) by the image sensor 104 and updates the display of the moving image displayed on the display element 116D, and the cycle of the light source flicker generated by a non-inverter type fluorescent lamp or the like. Is a phenomenon in which flickering with a period that is easily felt by human eyes appears in a moving image displayed on the display element 116D. The frequency of the light source flicker appears at twice the frequency of the commercial power supply. Therefore, even if the image capturing apparatus 100 performs storage at a constant period and time and update of the moving image display, the display flicker becomes noticeable depending on the frequency (period) of the light source flicker. There are cases where it is not. In order to effectively reduce display flicker, it is necessary to control the imaging operation of the image sensor 104 at a timing corresponding to the flicker frequency (cycle).

  Therefore, the imaging apparatus 100 according to the present invention detects the brightness or color component of the ambient light, and determines the power frequency of the commercial power supply supplied to the environment where the imaging apparatus 100 exists. A display flicker reduction processing method to be executed by the display flicker reduction processing unit is selected based on the detection result of the brightness or color component of the ambient light and the determination result of the power supply frequency by the power supply frequency determination unit.

  As described above, the ambient light detection unit 124 detects the brightness (luminance level) of ambient light based on the RGB three primary color image data generated by the synchronization processing unit. Alternatively, the ambient light detection unit 124 detects the component ratio (color balance) of the RGB three primary color image data based on the RGB three primary color image data generated by the synchronization processing unit. The ambient light detection unit 124 may also be configured to be able to detect both the brightness and color components of the ambient light.

  The CPU 122 inputs the ambient light detection result from the ambient light detection unit 124 and determines whether or not the ambient light is likely to be a fluorescent lamp. That is, when the brightness level of the ambient light is lower than a predetermined value, it can be estimated that the subject is illuminated with a fluorescent lamp. Alternatively, when the detection result of the color balance has more green components than other color components, it can be estimated that the subject is illuminated with a fluorescent lamp. Furthermore, it is possible to estimate that the subject is illuminated with a fluorescent lamp even when the luminance level of the ambient light is lower than a predetermined value and the green component is larger than other color components. .

  If there is a high possibility that the environmental light includes light from the fluorescent lamp, the power frequency of the commercial power source supplied to the environment where the imaging device 100 exists is determined, and display flicker reduction processing is performed based on the determination result. Whether to execute or not. Further, when it is determined that display flicker reduction processing is to be executed, the CPU 122 selects a display flicker reduction processing method corresponding to the determined power supply frequency. Note that the flicker frequency of a light source such as a fluorescent lamp is twice the frequency of the power source that supplies power to the light source (power frequency). Therefore, when the CPU 122 determines that the power supply frequency is 50 Hz as described above, the display flicker reduction processing method corresponding to the light source flicker of 100 Hz is selected. Further, when the CPU 122 determines that the power supply frequency is 60 Hz, the display flicker reduction processing method that dominates the 120 Hz light source flicker is selected.

  Alternatively, the user can set a desired display flicker reduction processing method by operating the display flicker reduction processing method setting unit 132. The display flicker reduction processing method setting unit 132 detects that the user operates an operation member (not shown) provided in the imaging apparatus 100 while looking at a menu displayed on the display element 116D, and displays flicker desired by the user. It can be implemented as selecting a reduction processing method.

  The display flicker reduction processing method selection process executed by the CPU 122 will be described below with reference to the flowchart of FIG. The processing of the flowchart shown in FIG. 2 is performed by the CPU 122 executing a program stored in the memory 120. The process of FIG. 2 is executed when the imaging apparatus 100 is turned on. Alternatively, it may be automatically executed at regular time intervals, or may be executed in response to the user operating the imaging apparatus 100 so as to perform display flicker reduction processing method selection processing. There may be.

  In S <b> 201, the CPU 122 determines whether or not the field luminance is lower than a predetermined value based on the ambient light detection result in the ambient light detection unit 124. If this determination is affirmative, that is, if it is determined that there is a high possibility that the field brightness is relatively dark and there is a high possibility that the imaging device 100 is in an environment with fluorescent lamp illumination, the process proceeds to S202 and the color balance of the fluorescent lamp is reached. It is determined whether or not. In FIG. 2, both the field luminance level and the color balance are determined, but as described above, the imaging apparatus 100 may be present in an environment with fluorescent lighting based on only one of them. It may be determined whether or not there is sex.

  The environmental light detection result in the environmental light detection unit 124 is also used for the determination in S202. That is, the CPU 122 determines whether or not the color component detection result in the ambient light detection unit 124 has more green components than other color components. If the determination in S202 is affirmative, that is, if it is determined that the green component is larger than the other color components, the CPU 122 proceeds to S203 and performs a power supply frequency determination process. This power supply frequency determination process is a process of determining the power supply frequency of a commercial power supply supplied to the environment where the imaging apparatus 100 exists. A specific example of this process will be described in detail later. On the other hand, if the determinations in S201 and S202 are both negative, that is, if it is determined that there is a low possibility that the ambient light is a fluorescent lamp, the display flicker reduction process is invalidated in S207, and the process returns. To do.

  In S204, the CPU 122 determines whether or not the power supply frequency has been successfully determined in S203. If the determination in S204 is affirmed, the process proceeds to S205, and the CPU 122 stores the determination result of the power supply frequency. On the other hand, if the determination in S204 is negative, that is, if the power supply frequency cannot be determined well, the process branches to S208. In S208, the CPU 122 reads the power frequency determination result stored previously, and proceeds to S206.

  A supplementary explanation will be given of the processing of S204, S205, and S208 described above. When the determination of the power supply frequency is successfully performed in S203, the CPU 122 stores the determination result as the latest power supply frequency determination result. On the other hand, if the determination of the power supply frequency cannot be performed successfully in S203, the previously stored power supply frequency determination result is read. The “previously stored power frequency determination result” means the power frequency determination result stored last. That is, even if the power frequency determination cannot be performed well at the present time, there is a problem if the display flicker reduction processing method is selected using the last stored power frequency determination result. Most likely not.

  In S206, the CPU 122 selects the display flicker reduction processing method corresponding to the power frequency determination result stored in S205 or the power frequency determination result read in S208, completes the processing in FIG. 2, and returns.

  Here, an example of a display flicker reduction processing method corresponding to the determination result of the power supply frequency will be described with reference to FIG. FIG. 3 is a table showing a combination example of the imaging rate (frame rate) set in the imaging apparatus 100 based on the determination result of the power supply frequency and the level of the object scene luminance and the accumulation time of the imaging element 104. (A) shows the case where the power supply frequency is 50 Hz (the flicker frequency is 100 Hz which is twice the frequency of the power supply for supplying power to the light source), and (b) shows the case where the power supply frequency is 60 Hz (flicker frequency). Shows the case of 120 Hz, which is twice the frequency of the power source that supplies power to the light source.

  In the table of FIG. 3A, when the field luminance is relatively high (from the first stage to the third stage in the table), the accumulation time t [seconds] of the image sensor 104 is the frame rate FPS [frames]. / Second = fps] is set to a value approximately equal to the reciprocal of the value. For example, when the frame rate is set to 240 fps, the accumulation time t [seconds] of the image sensor 104 is set to a value close to 1/240 seconds. On the other hand, when the field brightness is relatively low (from the 4th stage to the 6th stage in the table), the storage time t [second] of the image sensor is twice the value of the power supply frequency [Hz] (flicker frequency). ), And a value obtained by multiplying the value by a positive integer I (I = 1, 2,...) (1/100, 1/50,...).

  In the table of FIG. 3B, when the field luminance is relatively high (from the first to the third stage in the table), the imaging is performed in the same manner as described with reference to FIG. The accumulation time t [seconds] of the element 104 is set to a value substantially equal to the reciprocal of the value of the frame rate FPS [frames / second]. On the other hand, when the field brightness is relatively low (from the 4th stage to the 6th stage in the table), the storage time t [second] of the image sensor is twice the value of the power supply frequency [Hz] (flicker frequency). ), And a value obtained by multiplying that value by a positive integer I (I = 1, 2,...) (1/120, 1/60,...).

  By setting the frame rate and the accumulation time of the image sensor 104 in this way, it is possible to obtain a display flicker reduction effect as described below. First, the relationship between the accumulation time of the image sensor 104 and the flicker cycle will be described. By setting the accumulation period to a value obtained by multiplying the flicker cycle by a positive integer, the effect of flicker in an image obtained by imaging (accumulation) for one frame is almost the same between a plurality of temporally adjacent frame images. It becomes uniform. Therefore, display flicker hardly occurs in the moving image displayed on the display element 116D.

  On the other hand, when the storage time of the image sensor 104 is set to a value approximately equal to the reciprocal of the frame rate FPS [frames / second] when the field luminance is relatively high, the time interval between a plurality of temporally adjacent frame images is set. The influence of flicker is different. Therefore, although display flicker occurs, the frame rate is set to be relatively high (for example, approximately the same as or higher than the flicker frequency), so that the user hardly feels the presence of display flicker. This is similar to the fact that the flicker is hardly felt even if the fluorescent lamp being lit is directly viewed. In the present embodiment, the display rate of the moving image displayed on the image display unit 116 is set to be the same as the imaging frame rate.

  Timing at the time of imaging at the accumulation time and imaging rate described with reference to FIG. 3 is controlled based on a signal generated by the timing generation unit 114.

  The display flicker reduction processing method selection processing described with reference to FIG. 2 is performed by the display flicker reduction processing method selection unit 122b. That is, the processing method illustrated in (a) or (b) of FIG. 3 is selected according to the determination result of the power supply frequency in the power supply frequency determination unit 122a. Then, based on the control signal output from the CPU 122 to the image signal processing unit 112, the display flicker reduction processing unit 108 performs display flicker reduction processing by any one of the processing methods shown in FIGS. Hereinafter, various specific examples when the power frequency is determined by the CPU 122 will be described.

− First embodiment −
FIG. 4 is a block diagram showing a schematic configuration of the imaging apparatus 100-1 according to the first embodiment of the present invention. 4, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted. The imaging device 100-1 has a positioning unit (GPS receiver 401) using a satellite positioning system, receives positioning signals from a plurality of positioning satellites GS, and specifies the location of the imaging device 100-1 on the earth. To do.

  The power supply frequency determination unit 122a-1 accesses an internal database prepared for obtaining commercial power supply frequencies in various regions on the earth, and determines the power supply frequency corresponding to the location specified by the GPS receiver 401.

  The display flicker reduction processing method selection unit 122b selects a display flicker reduction processing method corresponding to the power frequency determination result in the power frequency determination unit 122a-1, and performs display flicker reduction processing using the selected display flicker reduction processing method. As described above, a control signal is issued to the image signal processing unit 112.

  Imaging device 100-1 can be implemented as a mobile phone having an imaging unit and a GPS receiver, for example. In that case, the GPS receiver 401 is originally provided for mobile phone applications. Therefore, it is possible to determine the power supply frequency without causing a particular increase in cost. Alternatively, even when the imaging device 100-1 is a device that records image data obtained by imaging together with data for specifying an imaging location acquired by a GPS receiver, without particularly increasing the cost. It is possible to determine the power supply frequency.

  In the first embodiment, an example in which the GPS receiver 401 is used as a positioning unit using a positioning satellite system has been described. However, other positioning satellite systems such as GLONASS (Global Navigation Satellite System) in Russia, Galileo in the European Union, Alternatively, it is possible to use the quasi-zenith satellite system planned by Japan or other positioning satellite systems planned in the near future that are planned in other countries.

  As described above, according to the imaging apparatus 100-1 according to the first embodiment, the user does not need to be aware of the commercial power supply frequency, and can always display a display in which display flicker is suppressed.

− Second Embodiment −
FIG. 5 is a block diagram showing a schematic configuration of an imaging apparatus 100-2 according to the second embodiment of the present invention. 5, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted. The imaging apparatus 100-2 includes a mobile communication function unit 501 and is configured to be able to communicate with the nearest base station BS.

  The mobile communication function unit 501 detects radio waves from one or more nearest base stations BS, and sends the signal strength to the position detection server LS via the base station BS. The position detection server LS identifies the position of the imaging device 100-2 from the position of the base station BS and the signal intensity, and sends the position identification result to the mobile communication function unit 501.

  The imaging device 100-2 can be implemented as, for example, a mobile phone having an imaging unit or a PHS. When the mobile communication function unit 501 uses, for example, a PHS system, it is possible to specify the position in the form shown in FIG. 6 (a) or (b). FIG. 6 is a diagram schematically illustrating the positional relationship between the imaging apparatus 100-2 and the base stations (BS-1, BS-2, BS-3, BS-4). In the PHS where the transmission output of the base station is relatively small, the arrangement density of the base stations is smaller than that of the mobile phone system. Therefore, as shown in FIG. 6A, the imaging device 100-2 may be located within the coverage area of a plurality of base stations. In this case, the mobile communication function unit 501 detects the signal strength of radio waves from each of the base stations BS-1, BS-2, BS-3, and the signal strength detection result is used as the base station BS-1, BS-2. -2, BS-3 is sent to the position detection server LS together with ID information that can be specified. The position detection server LS uses the position of each base station BS-1, BS-2, BS-3 and the signal strength when the mobile communication function unit 501 receives radio waves from each base station. The position is specified, and the position specifying result is sent to the mobile communication function unit 501.

  On the other hand, in the case of a system in which the transmission output of the base station is large, such as a mobile phone, the state as shown in FIG. 6A (the imaging device 100-2 is located within the coverage area of a plurality of base stations). 6), or a state as shown in FIG. 6B (a state in which the imaging device 100-2 is located within the cover area of a single base station). In the case as shown in FIG. 6 (b), it can only be understood that the imaging device 100-2 is located within a range in which a circle with a predetermined radius centered on the base station BS-4 is drawn. Nevertheless, it is sufficiently possible to specify the frequency of the commercial power supply supplied to the place where the imaging device 100-2 is located.

  The power supply frequency determination unit 122a-2 accesses an internal database prepared for obtaining commercial power supply frequencies in various regions where the mobile communication function unit 301 can receive radio waves. Then, the power supply frequency corresponding to the location information specified by the position detection server LS and sent to the mobile communication function unit 501 is determined.

  The display flicker reduction processing method selection unit 122b selects a display flicker reduction processing method corresponding to the power frequency determination result in the power frequency determination unit 122a-2, and performs display flicker reduction processing using the selected display flicker reduction processing method. As described above, a control signal is issued to the image signal processing unit 112.

  As described above, the imaging device 100-2 can be implemented as, for example, a mobile phone having an imaging unit or a PHS. In that case, the mobile communication function unit 501 is originally provided to perform a communication function of a mobile phone (PHS). Therefore, it is possible to determine the power supply frequency without causing a particular increase in cost. Note that in the imaging apparatus according to the second embodiment, communication costs may be incurred when communicating with the position detection server LS, so the display flicker reduction processing method selection shown in FIG. 2 is selected only when the user desires. You may make it perform the process of.

  As described above, also with the imaging apparatus 100-2 according to the second embodiment, the user does not need to be aware of the commercial power supply frequency and can display a display in which display flicker is suppressed.

− Third embodiment −
In 2nd Embodiment, although the imaging device 100-2 demonstrated the example which has the mobile communication function part 301 as FIG. 5 shows, the imaging device 100-3 which concerns on 3rd Embodiment is In addition, a communication function unit capable of communicating with a wireless communication facility having a narrower service area (hereinafter, such a wireless communication facility is referred to as a “small-scale wireless communication facility”). The configuration of the imaging device 100-3 is replaced with a wireless transmission / reception unit capable of communicating with a small-scale wireless communication facility in FIG. 5 showing the configuration of the imaging device 100-2 according to the second embodiment. It corresponds to that.

  Examples of the small-scale wireless communication equipment include a wireless LAN access point using the IEEE 802.11 standard, a wireless network using the Bluetooth (registered trademark) standard, a wireless network using an active wireless tag, and a network using IrDA. Is possible.

  FIG. 7 schematically illustrates a state in which the imaging apparatus 100-3 is located in a network 700 having a small-scale wireless facility. In the example shown in FIG. 7, the network 700 includes a master access point 702 and sensor access points 712, 714, and 716. When receiving the synchronization signal from the master access point 702, the sensor access points 712, 714, and 716 receive the positioning signal output from the imaging device 100-3. At this time, a difference occurs in the arrival time of the positioning signal due to a difference in distance between the imaging device 100-3 and the sensor access points 712, 714, and 716. Based on this difference in signal arrival time, the position detection server 720 can accurately determine the position of the imaging device 100-3. The imaging device 100-3 can receive position information from the position detection server 720, and based on this position information, can determine the power supply frequency of the commercial power source supplied to the location where the imaging device 100-3 is located. .

  The example shown in FIG. 7 is suitable for positioning with a precision of several meters or less in a relatively narrow region. On the other hand, in the imaging apparatus 100-3 according to the present invention, positioning is performed in order to determine the power supply frequency of the commercial power source supplied to the place where the imaging apparatus 100-3 is located, and therefore it is necessary to perform positioning with such accuracy. There is no. However, in the example shown in FIG. 7, it is possible to obtain positioning information even in places where it is difficult to receive radio waves from positioning satellites, such as in a building or underground.

  The imaging device 100-3 can be implemented as a camera that can transfer image data obtained by imaging, for example, to another server connected to a network. In that case, there is no need to add special hardware in order to obtain positioning information as described above, and therefore there is no increase in cost.

  Instead of the system shown in FIG. 7, a wireless access point that can be used by a public wireless access point or a service in which a wireless access point installed in a home or the like is mutually used (shared) between users The imaging device 100-3 according to the third embodiment may be configured to be connected to. In this case, the imaging apparatus 100-3 obtains ID information that can uniquely identify the wireless access point, for example, a MAC address, from the wireless access point that can be connected. Then, the information is transmitted to the positioning server together with information on the intensity of the radio wave emitted from the wireless access point. The positioning server has position information corresponding to the MAC address as a database, identifies the location where the imaging device 100-3 is located based on the information sent from the imaging device 100-3, and sets the location. The related positioning information is returned to the imaging device 100-3. The imaging apparatus 100-3 determines the frequency of the commercial power supply supplied to the place where the imaging apparatus 100-3 exists based on the above positioning information, and the display flicker reduction processing method selected based on the determination result To reduce flicker.

-Fourth embodiment-
In 2nd Embodiment, although the imaging device 100-2 demonstrated the example which has the mobile communication function part 301 as FIG. 5 shows, the imaging device 100-4 which concerns on 4th Embodiment is A television tuner capable of receiving terrestrial digital television broadcasting is provided. The configuration of the imaging device 100-4 corresponds to that obtained by replacing the mobile communication function unit 501 with a television tuner in FIG. 5 showing the configuration of the imaging device 100-2 according to the second embodiment. This TV tuner can be configured so as to be able to receive a broadcast by a one-segment partial reception service called “one-segment broadcasting” for mobile phones and mobile terminals.

  FIG. 8 schematically illustrates how the imaging apparatus 100-4 receives radio waves of terrestrial digital television broadcast transmitted from the transmission station 800. In the example illustrated in FIG. 8, the imaging device 100-4 can identify the current position from a receivable broadcast station. That is, in the digital terrestrial television broadcasting using the UHF band, the coverage area (receivable area) of one broadcasting station is relatively narrow with a diameter of about 20 km to 150 km. In addition, information such as service information (referred to as SI = Service Information) including program information and the like is superimposed on the broadcast radio wave. Accordingly, it is possible to specify the current position of the imaging apparatus 100-4 by receiving radio waves from a broadcasting station and referring to the service information and the like.

  The imaging device 100-4 can be implemented as a mobile phone having a function for receiving the one-segment broadcasting and an imaging function. In this case, it is not necessary to add special hardware for determining the power supply frequency as described above, and the cost is not increased.

-Fifth embodiment-
The fifth embodiment does not use wireless technology when determining the power supply frequency of the commercial power source supplied to the place where the imaging device is located. Then, instead of wireless technology or the like, as will be described in detail later, when charging a rechargeable battery used as a power source of the imaging apparatus, information is input from the charger and the power frequency is determined.

  FIG. 9 is a block diagram showing a schematic configuration of an imaging apparatus 100-5 according to the fifth embodiment of the present invention. In FIG. 9, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. The imaging apparatus 100-5 includes a battery communication function unit 901, and is configured to be able to read information recorded in a memory built in a rechargeable battery attached to the imaging apparatus 100-5.

  FIG. 10 is a block diagram schematically showing the configuration of the rechargeable battery 1020 and the charger 1000 for charging the rechargeable battery 1020. The rechargeable battery 1020 includes a rechargeable battery unit 1024 including a lithium ion battery, a nickel metal hydride battery, a memory 1022, and a connection portion 1026. The memory 1022 can be configured by an EEPROM or the like.

  The charger 1000 includes a transformer 1002, a diode bridge circuit 1004, a current / voltage stabilization unit 1006, an A / D converter 1010, a CPU 1012, a protection diode 1008, and a connection unit 1014. Rechargeable battery 1020 and charger 1000 are electrically connected via connection portions 1014 and 1026.

  The electricity that has been stepped down by the transformer 1002, full-wave rectified by the diode bridge 1004, and converted to direct current through the current / voltage stabilizing unit 1006 is supplied to the battery unit 1024 in the rechargeable battery 1020 through the connection units 1014 and 1026. And charged.

  In the block diagram shown in FIG. 10, an AC waveform stepped down by the transformer 1002 can be observed at point P. At the point Q, a waveform that is full-wave rectified by the diode bridge 1004 can be observed. The A / D converter 1010 receives the full-wave rectified waveform at the point Q, converts it into a digital signal, and outputs it to the CPU 1012. The CPU 1012 analyzes the signal input from the A / D converter 1010 and obtains the power supply frequency. The CPU 1012 writes information related to the power supply frequency in the memory 1022 provided in the rechargeable battery 1020 via the connection units 1014 and 1026.

  The rechargeable battery 1020 that has been charged is loaded into the imaging device 100-5. The battery communication function unit 901 shown in FIG. 9 accesses the memory 1022 in the loaded rechargeable battery 1020 and reads out information related to the power supply frequency described above.

  The power frequency determination unit 122a-5 determines the frequency of the commercial power supplied to the place where the imaging device 100-5 is located based on the information related to the power frequency. The display flicker reduction processing method selection unit 122b selects a display flicker reduction processing method corresponding to the power frequency determination result in the power frequency determination unit 122a-5, and performs display flicker reduction processing using the selected display flicker reduction processing method. As described above, a control signal is issued to the image signal processing unit 112.

  The imaging device 100-5 can be implemented as a mobile phone with an imaging function, a digital still camera, a digital movie camera, or the like. A memory may be built in the rechargeable battery to manage the number of charge / discharge cycles and to estimate the remaining capacity. However, diverting the memory used for such a purpose causes a significant cost increase. Thus, it is possible to determine the power supply frequency without any problem.

  In addition, although the example which connects and charges the rechargeable battery 1020 to the charger 1000 was demonstrated with reference to FIG. 10, the imaging device 100-5 was connected to the charger 1000, and the imaging device 100-5 was included. The loaded rechargeable battery 1020 may be charged. In this case, the charger 1000 can be a so-called cradle. Then, when the imaging device 100-5 is placed on the charger 1000, an electrical connection can be made between the charger 1000 and the imaging device 100-5. During charging, the CPU 1012 in the charger 1000 can write information related to the power supply frequency in the memory 1022 in the rechargeable battery 1020 via a connection unit (not shown) provided in the imaging device 100-5. it can. Instead of this, the CPU 122 in the imaging device 100-5 directly inputs information related to the power supply frequency as a configuration that allows communication between the CPU 1012 in the charger 1000 and the CPU 122 in the imaging device 100-5. It may be stored in the memory 120 or the storage medium 128.

  The present invention can be used for an imaging apparatus such as a digital still camera or a digital video camera, or a mobile phone having these imaging apparatuses.

1 is a block diagram schematically showing an internal configuration of an imaging apparatus to which the present invention is applied. 10 is a schematic flowchart illustrating a display flicker reduction processing method selection process executed in the imaging apparatus. 5 is a table for explaining an example of a display flicker reduction processing method, wherein (a) corresponds to a case where the power source frequency of the light source is 50 Hz, and (b) represents a flicker reduction processing method corresponding to a case where the power source frequency of the light source is 60 Hz. Show. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to a first embodiment of the present invention. It is a block diagram explaining the schematic structure of the imaging device which concerns on the 2nd Embodiment of this invention. In the 2nd Embodiment of this invention, it is a figure explaining the positional relationship of an imaging device and a mobile communication base station, (a) is an example in which an imaging device is located in the cover area of several base stations. , (B) shows an example in which the imaging device is located within the coverage area of a single base station. In the 3rd Embodiment of this invention, it is the figure which drawn typically a mode that the imaging device was located in the network which has a small-scale radio | wireless installation. It is the figure which drawn typically a mode that the imaging device which concerns on the 4th Embodiment of this invention received the terrestrial digital television broadcast electromagnetic wave sent out from a transmission station. It is a block diagram which shows roughly the internal structure of the imaging device which concerns on the 5th Embodiment of this invention. It is a block diagram which shows roughly the internal structure of the rechargeable battery used in the 5th Embodiment of this invention, and the charger for charging this rechargeable battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100, 100-1, 100-2, 100-3, 100-4, 100-5 Image pick-up device 102 Shooting lens 104 Image pick-up element 106 Synchronization processing part 108 Display flicker reduction processing part 110 Image processing part 112 Image signal processing part 114 Timing generation unit 116 Image display unit 116C Display control unit 116D Display element 118 Memory control unit 120 Memory 122 CPU
122a, 122a-1, 122a-2, 122a-5 Power frequency determination unit 122b Display flicker reduction processing method selection unit 124 Ambient light detection unit 126 Interface 128 Storage medium 130 System bus 132 Display flicker reduction processing method setting unit 401 GPS receiver 501 Mobile communication function unit 901 Battery communication function unit 1000 Charger 1002 Transformer 1004 Bridge diode 1006 Current / voltage stabilization unit 1008 Protection diode 1010 A / D converter 1012 CPU
1014, 1026 Connection unit 1020 Rechargeable battery 1022 Memory 1024 Battery unit

Claims (7)

An imaging apparatus capable of displaying a moving image on an image display unit based on image signals sequentially read from an imaging element,
In order to reduce display flicker caused by light source flicker in the moving image displayed on the image display unit, one of the plurality of display flicker reduction processing methods corresponding to different light source flicker frequencies is supported. A display flicker reduction processing unit configured to be able to perform the display flicker reduction processing using the display flicker reduction processing method to be performed;
An ambient light detector that detects the brightness or color component of the light surrounding the subject;
A power supply frequency determination unit that determines a power supply frequency of a commercial power supply that is supplied to an environment in which the imaging device exists;
Display to be executed by the display flicker reduction processing unit based on the detection result of the brightness or color component of the light surrounding the subject by the ambient light detection unit and the determination result of the power supply frequency by the power supply frequency determination unit An image pickup apparatus comprising: a display flicker reduction processing method selection unit that selects a flicker reduction processing method. The power frequency determination unit includes a location specifying information input unit that inputs location specifying information that is information for specifying a location where the imaging device exists,
The imaging apparatus according to claim 1, wherein a power supply frequency of a commercial power supply supplied to an environment where the imaging apparatus exists is determined based on the location specifying information.   The location specifying information input unit determines a power frequency of a commercial power source supplied to an environment where the imaging device exists based on positioning information acquired from a positioning unit using a satellite positioning system. Item 3. The imaging device according to Item 1 or 2.   The location specifying information input unit determines a power frequency of a commercial power source supplied to an environment where the imaging device exists based on positioning information acquired from a base station of a mobile terminal device including a mobile phone and a PHS. The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized.   The location specifying information input unit is based on location information acquired from a location detection server configured to be able to detect the location of a client connected to a network via a wireless LAN access point. The imaging apparatus according to claim 1, wherein a power supply frequency of a commercial power supply to be supplied is determined.   The location specifying information input unit is configured to capture the image based on location information acquired from a location detection server configured to be able to detect a location of a client connected to a network using a wireless LAN, Bluetooth, or active wireless tag wireless technology. The imaging apparatus according to claim 1, wherein the power supply frequency of a commercial power supply supplied to an environment where the apparatus exists is determined. When a rechargeable battery for supplying power to the imaging device is charged using the commercial power source, a power frequency is detected, and power frequency information, which is information related to the power frequency, is stored in the imaging device or Stored in the information storage unit provided in the rechargeable battery,
The power supply frequency determination unit is configured to determine a power supply frequency of a commercial power supply supplied to an environment in which the imaging device exists based on the power supply frequency information stored in the information storage unit. The imaging apparatus according to 1.

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