JP2020008807A - Imaging apparatus, display control device, and control method and display control method of imaging apparatus - Google Patents

Abstract

To perform live view display that has high quality and is capable of easily performing framing when performing automatic focus control under low illuminance.SOLUTION: An imaging apparatus includes: focus control means for performing automatic focus control; display control means for controlling a display part; and calculation means for calculating the amount of emission of auxiliary light emitted by an emission part when acquiring an image used for automatic focus control by the focus control means. The calculation means calculates the amount of emission of the auxiliary light on the basis of an image obtained by allowing the emission part to emit light. The display control means does not display an image obtained by allowing the emission part used for calculating the amount of emission of the auxiliary light by the calculation means to emit light when performing live view display, and displays an image obtained by allowing the auxiliary light to emit light with the amount of emission calculated by the calculation means on the display part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to image display at the time of emission of auxiliary light for focus control.

  2. Description of the Related Art In recent years, a so-called imaging surface AF technique of performing automatic focus control (Auto Focus: AF) using an image acquired by an imaging sensor for acquiring a recording image has been known. During execution of the imaging plane AF, auxiliary light may be emitted in a dark place or the like. 2. Description of the Related Art In an image pickup apparatus that uses a light emitting unit such as a strobe to brighten an image of an object, a light emitting unit such as a strobe can be used as auxiliary light.

  In the case of a light source such as a strobe that intermittently emits flash light, performing live view display of an image at the time of auxiliary light emission may degrade the quality of live view display. Therefore, in Japanese Patent Application Laid-Open No. H11-163, the light emission for preventing red-eye is performed during the non-exposure period of the imaging surface, so that a change in luminance due to the light emission is not displayed on the live view display.

JP 2004-72237 A

  However, when the auxiliary light is emitted by flash light emission under low illuminance where it is difficult to perform the AF without the auxiliary light, a live view display of the image at the time of the auxiliary light emission is required to facilitate framing for a photographer. desirable.

  Therefore, an object of the present invention is to provide a live view display with high quality and easy framing when performing automatic focus control under low illuminance.

  In order to solve the above problems, an imaging apparatus according to the present invention obtains an image used for automatic focus control by a focus control unit for performing automatic focus control, a display control unit for controlling a display unit, and the focus control unit. Computing means for calculating the amount of auxiliary light emitted by the light-emitting unit when the light-emitting unit emits light, wherein the arithmetic means calculates the amount of auxiliary light emitted based on an image obtained by causing the light-emitting unit to emit light. The display control means calculates, when performing live view display, an image obtained by causing the light emitting section used for calculating the light emission amount of the auxiliary light by the calculating means to emit light is displayed on the display section. An image obtained by emitting the auxiliary light at the light emission amount calculated by the calculation means without displaying the image is displayed on the display unit.

  ADVANTAGE OF THE INVENTION According to this invention, when performing automatic focus control under low illuminance, it is possible to perform live view display with high quality and easy framing.

FIG. 2 is a block diagram of the imaging device according to the first embodiment of the present invention. FIG. 3 is a diagram showing a timing chart including auxiliary light control for automatic focus control according to the first embodiment of the present invention. FIG. 9 is a diagram illustrating a timing chart including auxiliary light control for automatic focus control according to a second embodiment of the present invention.

(1st Embodiment)
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating a basic configuration of an imaging device 100 that is one example of realizing the display control device according to the first embodiment. Note that the technical scope of the present invention is determined by the claims, and is not limited by the following individual embodiments. In addition, all combinations of the features described in the embodiments are not necessarily essential to the present invention.

  The imaging device 100 may be any electronic device having a camera function, such as a camera such as a digital camera and a digital video camera, a mobile phone with a camera function, and a computer with a camera. The optical system 101 includes a lens group including a focus lens, a shutter, and an aperture, and forms light from a subject on the image sensor 102 under the control of the camera control unit 104. An image sensor 102 such as a CCD image sensor or a CMOS image sensor converts light focused through the optical system 101 into an image signal.

  The focus detection circuit 103 is a circuit that generates a signal value for automatic focus control using, for example, an image obtained by the imaging element 102. The camera control unit 104 controls the focus lens included in the optical system 101 using the focus control unit 116 based on the signal value output from the focus detection circuit 103 so that the subject is focused. Note that the signal value for the automatic focus control may be a known signal value in the automatic focus control, such as a contrast value of an image or a defocus amount by detecting a phase difference.

  The camera control unit 104 realizes the function of the imaging device 100 by controlling each unit constituting the imaging device 100 according to an input signal or a program stored in a memory in advance. The primary storage device 105 is a volatile device such as a RAM, for example, and stores temporary data and is used for the operation of the camera control unit 104. The primary storage device 105 is used to hold the light emission amount calculated by the light emission amount calculation unit 110, the light emission upper limit number calculated by the light emission upper limit calculation unit 111, and to hold information to be recorded on the recording medium 107. Is done. The secondary storage device 106 is, for example, a nonvolatile storage device such as an EEPROM, and stores a program (firmware) for controlling the imaging device 100 and various setting information, and is used by the camera control unit 104.

  The recording medium 107 records data of an image obtained by shooting, which is stored in the primary storage device 105. Note that the recording medium 107 is detachable from the imaging device 100 like a semiconductor memory card, for example, and the recorded data can be read out by attaching it to a personal computer or the like. That is, the imaging device 100 has a mechanism for attaching and detaching the recording medium 107 and a read / write function.

  The display unit 108 includes a display panel such as a liquid crystal display or an organic EL display, and performs live view display of an image, playback display of a captured image, and display of a GUI image for interactive operation. The operation unit 109 is an input device group that receives an operation of a user and transmits input information to the camera control unit 104, and may be, for example, an input device using a voice, a line of sight, or the like, such as a button, a lever, or a touch panel.

  The camera control unit 104 sends a control signal to the light emission control unit 114 to control the light emission unit 113 and the external accessory communication unit 112. The light emitting unit 113 is a light emitting unit using a LED or a xenon tube built in the imaging device 100 as a light source, and the external accessory communication unit 112 communicates with an external accessory attached to the imaging device 100, for example, an external strobe. When the external accessory is an external flash, the light emission control unit 114 controls the external flash via the external accessory communication unit 112. The camera control unit 104 and the light emission control unit 114 are connected to a common timer control unit 115, and receive a common timing signal.

  The light emission amount calculation unit 110 calculates the auxiliary light (AF auxiliary light) for automatic focus control and the auxiliary light (AF auxiliary light) from the reflected light when the external strobe or the like controlled by the light emitting unit 113 or the external accessory communication unit 112 is emitted. The amount of light required for the light emission (main light emission) is determined. In addition, the method of obtaining the light emission amount from the reflected light at the time of light emission is a known method, and the detailed description is omitted. The light emission upper limit number calculation unit 111 calculates the charging capacity required for the main light emission based on the light emission amount obtained by the light emission amount calculation unit 110, and calculates the AF auxiliary light emission upper limit number that can keep the charge amount. The obtained upper limit number of light emission is stored in the primary storage device 105, and is used when the camera control unit 104 performs light emission control.

  Next, an image display at the time of emission of the auxiliary light for focus control will be described. FIG. 2 is a diagram showing a timing chart including auxiliary light control for automatic focus control. In FIG. 2, the exposure period of each image is set by a VD signal instructing reading of an image signal from the image sensor 102, and one image corresponds to each exposure period of frames 1 to 10. . Hereinafter, images corresponding to the respective exposure periods of frames 1 to 10 are referred to as frame images 1 to 10, respectively.

  Frames 1 and 2 are frames that do not emit light. The camera control unit 104 provides a live view display to the user by sequentially displaying images based on the image signals obtained from the image sensor 102 on the display unit 108. In the live view display under low illuminance, the readout sensitivity of the image sensor 102 is raised to the maximum usable sensitivity, and when the brightness is insufficient, the imaging frame rate is changed within a certain range to secure the exposure time. We are devising. An image based on the image signal obtained from the image sensor 102 during this period can be displayed on the display unit 108. When the camera control unit 104 receives a shooting preparation instruction or an AF instruction by a user operation on the operation unit 109, the focus control unit 116 starts an AF operation. The focus control unit 116 evaluates the luminance levels of the frame image 1 and the frame image 2, and generates an AF auxiliary light emission request signal if the luminance level is equal to or less than a predetermined value. The camera control unit 104 receives the AF auxiliary light emission request signal from the focus control unit 116 and starts an AF auxiliary light control sequence.

  Frames 3 and 4 are frames in which light control is performed to determine the amount of light emitted from the light emitting unit 113 or the external strobe required for performing AF. The camera control unit 104 controls the light emission control unit 114 to emit the first light emission amount in the frame 3 and emit the second light emission amount larger than the first light emission amount in the frame 4. The first light emission amount is a design value held in the secondary storage device 106. For example, a lens having an open aperture value of F5.6 is attached, and a Gno value at which a subject at a distance of 1m can be AF-lit in the dark by ISO3200 is set by ISO3200. . The second light emission amount is set to a Gno value at which a subject at a distance of 10 m can be AFed in the dark under the same exposure condition. As described above, by performing the light emission twice with the first light emission amount corresponding to the short-distance subject and the second light emission amount corresponding to the long-distance subject, it is possible to obtain the auxiliary light emission amount regardless of the distance to the subject. Dimming control can be accurately performed.

  Also, the exposure value of the image sensor 102 is in accordance with the design value. For example, a lens having an open aperture value of F5.6 is attached, and the exposure value is set to be under in non-light emission under low illuminance such as 1/60 according to ISO3200. , The frame rate of the image sensor 102 is increased.

  The luminance level of the estimated subject area is evaluated from the frame images 3 and 4 obtained in the two light control frames (frame 3 and frame 4). Then, based on the evaluation result, for example, when the ISO value to be used during the auxiliary light AF control is ISO3200, the third light emission amount that is the auxiliary light emission amount suitable for AF is determined in ISO3200. The third method of determining the light emission amount may be a known method as described above, and may use both the frame image 3 and the frame image 4, or any one of which can more accurately evaluate the luminance level of the estimated subject area. May be used alone.

  At this time, if the third light emission amount is larger than the maximum light emission amount of the light emitting unit 113 or the external strobe, the adjustment is performed including the exposure setting of the image sensor 102. Specifically, for example, the ISO value used during the auxiliary light AF control is set to a value higher than the preset ISO 3200 (for example, ISO 6400), and the auxiliary light emission amount to be used is smaller than the third light emission amount. The light emission amount is equal to or less than the light emission amount (for example, half of the third light emission amount).

  Since the frame image 3 and the frame image 4 are images obtained in the dimming control frame, the brightness is different from the frame image 2 and the brightness of each image is also different. Therefore, when the live view display of the frame image 3 and the frame image 4 is performed after the frame image 2, the camera control unit 104 does not display the frame image 3 and the frame image 4 on the display unit 108. Then, the frame image 2 which is an image obtained immediately before the frame 3 is continuously displayed until an image obtained after the frame image 4 can be displayed.

  During the exposure period of frame 5, the camera control unit 104 determines the amount of auxiliary light emission and the exposure value at the time of auxiliary light emission. In the frame 5, the light emission of the light emitting unit 113 and the external strobe is not performed, and the frame image 5 is obtained using the same exposure value as the frames 1 and 2. The acquired frame image 5 is displayed on the display unit 108 following the frame image 2.

  In FIG. 2, AF auxiliary light control is performed in frames 6 to 9. In the frame 6, the camera control unit 104 controls the light emission unit 113 or the external strobe to emit light using the light emission control unit 114. At this time, the values determined in the frame 5 are used as the light emission amount and the exposure value. The camera control unit 104 performs the AF using the focus control unit 116 based on the frame image 6 acquired in the frame 6. Further, the camera control unit 104 causes the display unit 108 to display the frame image 6 following the frame image 5.

  Frames 7 to 9 perform the same control as frame 6. That is, the frames 7 to 9 also emit auxiliary light, and the obtained frame images 7 to 9 are displayed on the display unit 108. Since the frame images 6 to 9 are images obtained by emitting the auxiliary light with the adjusted light emission amount, the brightness of the images is substantially the same, so that flickering can be suppressed even in live view display. Further, since a plurality of images irradiated with the auxiliary light are continuously displayed in live view, framing is easy even under low illuminance.

  Since the frame images 6 to 9 are images obtained by emitting the auxiliary light, the camera control unit 104 performs white balance adjustment based on the color temperature of the auxiliary light.

  Further, during the frames 6 to 9, the camera control unit 104 performs the AF by the focus control unit 116, so that the focus lens included in the optical system 101 moves sequentially. When the focus lens included in the optical system 101 moves, the brightness level of the image may fluctuate even when the exposure value is the same. In addition, the brightness level of an image may fluctuate when the subject to which the strobe light is irradiated comes into focus. Thus, the camera control unit 104 may evaluate the luminance level of the frame image in which the auxiliary light has been emitted, and may change the amount of auxiliary light emission in the frame in which the auxiliary light is emitted after the evaluation.

  As described above, in the present embodiment, the light emission image in which the light emission for determining the light emission amount of the automatic focus control auxiliary light is not displayed in the live view, and the light emission of the automatic focus control auxiliary light is performed. The emission image is displayed in live view. Thus, when performing automatic focus control under low illuminance, live view display with high quality and easy framing can be performed.

(Second embodiment)
Next, a second embodiment will be described with reference to FIG. FIG. 3 is a diagram showing a timing chart including auxiliary light control for automatic focus control according to the second embodiment. In the present embodiment, unlike the first embodiment, a combined image obtained by combining a non-light-emitting image in which no light is emitted and a light-emitting image in which auxiliary light is emitted is displayed in live view. As in the first embodiment, in a configuration in which a light emission image in which the auxiliary light is emitted is displayed in a live view, framing is easy for a subject to which the auxiliary light is applied, but an area where the auxiliary light is not applied is easy. Is dark and difficult to frame. For this reason, in the present embodiment, the area of the non-light-emission image obtained by increasing the exposure (including the ISO sensitivity), which is not irradiated with the auxiliary light, and the subject to which the light emission of the light-emission image is irradiated are synthesized. , A bright image is generated, and the generated composite image is displayed in live view.

  As shown in FIG. 3, since the frame 5 does not emit light, the obtained frame image 5 is a non-emission image. On the other hand, in the frames 6 to 9, the frame images 6 to 9 obtained because the auxiliary light is emitted are light emission images.

  Therefore, an image obtained by synthesizing the frame image 5 and the frame image 6 is displayed in live view following the frame image 5. Thereafter, an image obtained by synthesizing the latest light-emitting image and the frame 5 is displayed in live view.

  As described above, in the present embodiment, the light emission image in which the light emission for determining the light emission amount of the automatic focus control auxiliary light is not displayed in the live view, and the light emission of the automatic focus control auxiliary light is performed. The emission image is displayed in live view. Thus, when performing automatic focus control under low illuminance, live view display with high quality and easy framing can be performed. Furthermore, by synthesizing a non-light-emitting image with a light-emitting image in which the auxiliary light has been emitted and performing live view display, a live view display in which framing is easily performed as a whole can be performed.

  As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

  For example, in the above two embodiments, the light emission is performed twice with the first light emission amount and the second light emission amount in order to determine the light emission amount of the auxiliary light. Is also good.

  Further, in the above two embodiments, the number of times of emission of the auxiliary light is the number of times calculated by the upper limit number of emission times calculation unit 111, but may be predetermined, or whether the camera control unit 104 has focused on the subject. The stop of the emission of the auxiliary light may be determined based on the determination.

  In the above two embodiments, the display control of the display unit 108 included in the imaging device 100 is performed. However, the present invention is also applied to the display control of the display unit of the display device separated from the imaging device 100. it can. In the case of such a configuration, the control unit of the display device may execute a part of the processing that was performed by the camera control unit 104 of the imaging device 100 in the above two embodiments. In such a configuration, the display device functions as a display control device.

Reference Signs List 100 imaging device 101 optical system 102 imaging element 103 focus detection circuit 104 camera control unit 108 display unit 110 light emission amount calculation unit 112 external accessory communication unit 113 light emission unit 114 light emission control unit 116 focus control unit

Claims (11)

Focus control means for performing automatic focus control;
Display control means for controlling the display unit;
Calculating means for calculating the amount of auxiliary light emitted by the light emitting unit when acquiring an image used for automatic focus control by the focus control means,
The calculating means calculates a light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light,
The display control unit does not display an image obtained by causing the light emitting unit used to calculate the light emission amount of the auxiliary light by the calculating unit when performing live view display on the display unit. And an image obtained by emitting the auxiliary light with the light emission amount calculated by the calculation means, and displaying the image on the display unit. Focus control means for performing automatic focus control;
Display control means for controlling the display unit;
Calculating means for calculating the amount of auxiliary light emitted by the light emitting unit when acquiring an image used for automatic focus control by the focus control means,
The calculating means calculates a light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light,
The display control unit does not display an image obtained by causing the light emitting unit used to calculate the light emission amount of the auxiliary light by the calculating unit when performing live view display on the display unit. A combined image obtained by combining an image obtained by emitting the auxiliary light with the light emission amount calculated by the calculating unit and an image obtained without causing the light emitting unit to emit light is displayed on the display unit. Imaging device.   The calculation means is configured to calculate an image obtained by causing the light emitting unit to emit light at a first light emission amount and an image obtained by causing the light emitting unit to emit light at a second light emission amount different from the first light emission amount. The imaging apparatus according to claim 1, wherein a light emission amount of the auxiliary light is calculated.   The display control means, when performing live view display, displays an image obtained after illuminating the light emitting unit used for calculating the light emission amount of the auxiliary light by the calculation means. Until it becomes possible, the image obtained immediately before the image obtained by causing the light emitting unit used for calculating the light emission amount of the auxiliary light by the calculating unit to be continuously displayed on the display unit. The imaging device according to claim 1, wherein:   5. The display control unit according to claim 1, wherein when performing live view display, an image obtained without causing the light emitting unit to emit light is displayed on the display unit. 6. Imaging device. Focus control means for performing automatic focus control; and calculation means for calculating a light emission amount of auxiliary light to be emitted by a light emitting unit when acquiring an image used for automatic focus control by the focus control means, wherein the calculation means A display control device that displays an image obtained by an imaging device that calculates the light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light on a display unit,
When performing live view display, an image obtained by causing the light emitting unit used to calculate the light emission amount of the auxiliary light by the calculating unit to emit light is not displayed on the display unit, but is calculated by the calculating unit. A display control device, comprising: display control means for displaying an image obtained by emitting auxiliary light at the determined light emission amount on the display unit. Focus control means for performing automatic focus control; and calculation means for calculating a light emission amount of auxiliary light to be emitted by a light emitting unit when acquiring an image used for automatic focus control by the focus control means, wherein the calculation means A display control device that displays an image obtained by an imaging device that calculates the light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light on a display unit,
When performing live view display, an image obtained by causing the light emitting unit used to calculate the light emission amount of the auxiliary light by the calculating unit to emit light is not displayed on the display unit, but is calculated by the calculating unit. A combined image obtained by combining the image obtained by emitting the auxiliary light with the light emission amount and the image obtained without causing the light emitting unit to emit light has display control means for displaying the combined image on the display unit. Display control device. A focus control step for performing automatic focus control;
A display control step of controlling the display unit;
A calculating step of calculating a light emission amount of auxiliary light to be emitted by a light emitting unit when acquiring an image used for automatic focus control in the focus control step,
The calculating step calculates a light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light,
The display control step, when performing a live view display, the display step does not display the image obtained by emitting the light emitting unit used to calculate the light emission amount of the auxiliary light in the calculation step And an image obtained by emitting the auxiliary light with the light emission amount calculated in the calculation step, and displaying the image on the display unit. A focus control step for performing automatic focus control;
A display control step of controlling the display unit;
A calculating step of calculating a light emission amount of auxiliary light to be emitted by a light emitting unit when acquiring an image used for automatic focus control in the focus control step,
The calculating step calculates a light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light,
The display control step, when performing a live view display, the display step does not display the image obtained by emitting the light emitting unit used to calculate the light emission amount of the auxiliary light in the calculation step A combined image obtained by combining an image obtained by emitting the auxiliary light with the light emission amount calculated in the calculation step and an image obtained without causing the light emitting unit to emit light is displayed on the display unit. The control method of the imaging device described above. Focus control means for performing automatic focus control; and calculation means for calculating a light emission amount of auxiliary light to be emitted by a light emitting unit when acquiring an image used for automatic focus control by the focus control means, wherein the calculation means Is a display control method of displaying an image obtained by an imaging device that calculates the light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light on a display unit,
When performing live view display, an image obtained by causing the light emitting unit used to calculate the light emission amount of the auxiliary light by the calculating unit to emit light is not displayed on the display unit, but is calculated by the calculating unit. A display control method, characterized in that an image obtained by emitting auxiliary light at the determined light emission amount is displayed on the display unit. Focus control means for performing automatic focus control; and calculation means for calculating a light emission amount of auxiliary light to be emitted by a light emitting unit when acquiring an image used for automatic focus control by the focus control means, wherein the calculation means Is a display control method of displaying an image obtained by an imaging device that calculates the light emission amount of the auxiliary light based on an image obtained by causing the light emitting unit to emit light on a display unit,
When performing live view display, an image obtained by causing the light emitting unit used to calculate the light emission amount of the auxiliary light by the calculating unit to emit light is not displayed on the display unit, but is calculated by the calculating unit. A display control method, wherein a combined image obtained by combining an image obtained by emitting the auxiliary light with the set light emission amount and an image obtained without emitting the light from the light emitting unit is displayed on the display unit.

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