JP6320105B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus and a control method thereof.

  An imaging apparatus such as a digital camera or a digital video camera provided with a filter that removes an infrared light component from a light component incident on an imaging element from an imaging optical system has been proposed. The image pickup device is equipped with this filter because the image sensor has sensitivity to infrared light components, so the color reproducibility of the captured image is reduced due to the mixture of infrared light components, and resolution due to aberrations. It is for preventing that falls.

  On the other hand, in order to enable photographing in a dark place where the amount of visible light is insufficient, an imaging apparatus provided with a filter switching means that puts and removes an infrared light removal filter on the optical path of the imaging optical system has been proposed. Yes. In this imaging apparatus, an infrared light removal filter is placed on the optical path for photographing with normal visible light, and the infrared light removal filter is moved out of the optical path in a dark place where there is little visible light. Thereby, photographing with infrared light is also possible. Hereinafter, a photographing mode for photographing with normal visible light is described as a visible light photographing mode. In addition, a photographing mode for photographing with infrared light is described as an infrared light photographing mode.

  When the infrared light removal filter is put in and out of the optical path when the photographing mode is switched between the visible light photographing mode and the infrared light photographing mode, the focus of the imaging optical system depends on the presence or absence of the infrared light removal filter. The state changes. Therefore, when the focus lens position for adjusting focus is switched to the infrared light shooting mode with the subject focused in the visible light shooting mode, the infrared light removal filter moves out of the optical path. The subject is out of focus.

  In general, an imaging apparatus includes both an autofocus mode in which an automatic focusing operation is performed and a manual focus mode in which a manual focusing operation is performed as means for focusing a subject image. The manual focusing operation is an operation in which the photographer manually drives the focus lens to perform focusing. If the imaging apparatus is in the autofocus mode, control for automatically focusing is performed even if the infrared light removal filter moves out of the optical path. On the other hand, when the imaging apparatus is in the manual focus mode, it is necessary to correct the focus lens position so as to cancel out the focus change due to the presence or absence of the infrared light removal filter in order to maintain the focused state of the subject.

  Here, if the manual focus mode is set while the subject is focused in the visible light shooting mode, the focus lens position cannot be accurately corrected when the mode is switched to the infrared light shooting mode, and the focus is blurred. Therefore, Patent Document 1 discloses an imaging apparatus that switches to manual focus mode after switching to autofocus mode when switching to infrared light shooting mode.

JP 2012-27156 A

  When the imaging device disclosed in Patent Document 1 is switched to the infrared light imaging mode, the in-focus state between the case where the infrared light removal filter is disposed on the optical path and the case where the infrared light removal filter is disposed outside the optical path is provided. The focus lens is moved by the correction amount of the focus lens position for correcting the shift. Thereafter, the imaging apparatus switches to the autofocus mode and detects the focus position. However, since the imaging device disclosed in Patent Document 1 does not disclose the driving start direction and the driving range in the autofocus operation, there are the following problems when this imaging device is applied. When the imaging device starts driving in the opposite direction to the in-focus direction during autofocus operation or detects the focus position without limiting the drive range, the subject is different from the subject that was focused with manual focus. The camera may be in focus or the focus position may not be detected. In this case, the imaging apparatus has to refocus the subject that has been focused in the visible light photographing mode by the manual focus operation.

  The present invention makes it possible to maintain a good in-focus state for a subject that is in focus in the visible light photographing mode even when the infrared light photographing mode is switched in the manual focusing operation state in the visible light photographing mode. An object of the present invention is to provide an imaging apparatus that performs the above-described process.

An imaging apparatus according to an embodiment of the present invention includes a visible light imaging mode in which an infrared light removal filter is positioned on an optical path of an imaging optical system to perform imaging using visible light, and the infrared light removal filter is imaged. An imaging apparatus having an infrared light imaging mode in which imaging using infrared light is performed by retracting from the optical path of the optical system. When the imaging device is switched from the visible light photographing mode to the infrared light photographing mode in a state where the focus lens is driven and focused in the manual focusing operation in the visible light photographing mode, and focus correcting means for correcting the focus change due to retraction of light removal filter, after the focus change is corrected, and control means for controlling driving of the focus lens so as to perform hill-climbing operation for focusing position detection Prepare. The control means is based on a positional relationship between a focus position under a visible light environment and a focus position under an infrared light environment in a state where the infrared light removal filter is retracted from the optical path of the imaging optical system. Dzu rather controls the driving of the focus lens to perform hill-climbing operation direction.

  According to the imaging apparatus of the present invention, even if the manual focusing operation state in the visible light photographing mode is switched to the infrared light photographing mode, the in-focus state is favorably improved for the subject that has been focused in the visible light photographing mode. It becomes possible to keep.

It is a figure which shows the structural example of the imaging device of this embodiment. 6 is a flowchart illustrating focus adjustment control processing according to the first exemplary embodiment. It is a flowchart explaining a one-shot focus process. It is a figure explaining the drive start direction and drive range of a focus lens. It is a figure explaining the drive start direction and drive range of a focus lens. 6 is a flowchart illustrating focus adjustment control processing according to the first exemplary embodiment. It is a figure which shows the relationship between the correction amount of a focus lens position, and zoom.

  FIG. 7 shows the correction amount of the focus lens position and the zoom lens position when the infrared light removal filter is retracted from the optical path to the outside of the optical path in the imaging lens having a zoom lens for changing the magnification of the imaging optical system. It is a figure which shows a relationship.

  A curve L1 in the graph of FIG. 7 indicates the correction amount of the focus lens position in an environment with only visible light. The left end of the graph of FIG. 7 shows the end position on the wide angle side of the zoom lens, and the right end shows the end position on the telephoto side. A curve L2 in the graph of FIG. 7 indicates the correction amount of the focus lens position under an environment of only infrared light, and is greatly different from the curve L1. In an environment in which visible light and infrared light components are mixed, the correction amount of the focus lens position is an intermediate characteristic between L1 and L2. As described above, the correction amount changes depending on the component ratio of the visible light and the infrared light because of the chromatic aberration characteristic of the lens of the imaging optical system. The focus position of the subject that was in focus in the visible light shooting mode after switching to the infrared light shooting mode is the focus position in the visible light environment when the infrared light removal filter is retracted from the optical path. It is between the position and the focus position in the infrared light environment.

  In FIG. 7, the difference in the correction amount of the focus lens position between the visible light environment and the infrared light environment is several times to ten times as large as the shift amount of the focus lens position at which the out-of-focus blur can be seen. It has become. Although it is conceivable to correct the visible light environment or the infrared light environment based on the ratio of the three primary color signals, the error in the correction amount is large and the change in the focus state due to the presence or absence of the infrared light removal filter is sufficiently offset. I can't. Therefore, if the manual focus mode is set while the subject is focused in the visible light shooting mode, the focus lens position cannot be accurately corrected when the mode is switched to the infrared light shooting mode, and the focus is blurred.

  According to the imaging apparatus of the present embodiment described below, even if the manual focusing operation state in the visible light photographing mode is switched to the infrared light photographing mode, the subject that has been focused in the visible light photographing mode is adjusted. It becomes possible to keep the focus state good.

Example 1
FIG. 1 is a diagram illustrating a configuration example of an imaging apparatus according to the present embodiment.
The imaging device illustrated in FIG. 1 is a digital camera or a digital video camera. This imaging apparatus is capable of both capturing a visible light image and capturing an infrared light image. For this purpose, the imaging apparatus has a visible light photographing mode and an infrared light photographing mode. The visible light photographing mode is a photographing mode in which the infrared light removing filter 118 is positioned on the optical path of the imaging optical system and photographing using visible light is performed. The infrared light photographing mode is a photographing mode in which the infrared light removing filter 118 is retracted from the optical path of the imaging optical system and photographing using infrared light is performed.

  The imaging apparatus includes a fixed first group lens 101 to a zoom operation unit 122. The fixed first group lens 101 guides subject light to the imaging optical system. The zoom lens 102 performs a zooming operation. The diaphragm 103 adjusts the amount of subject light guided to the image sensor 106. The subject light passing through the aperture is guided to the focus lens 105 through the fixed second group lens 104. The focus lens 105 has both a function of correcting the movement of the focal plane accompanying zooming and a function of focusing. The first group lens 101 to the focus lens 105 constitute an imaging optical system that forms an image of incident light.

  The infrared light removal filter 118 removes an infrared light component from the subject light guided from the focus lens 105 and guides it to the image sensor 106. The infrared light removal filter 118 can be retracted out of the optical path of the imaging optical system by a driving mechanism (not shown). The image sensor 106 photoelectrically converts subject light and outputs an image signal. The image sensor 106 is a CCD sensor, a CMOS sensor, or the like. The image sensor control circuit 107 controls the operation of the image sensor 106 and samples the output of the image sensor 106.

  The camera signal processing circuit 108 performs various types of image processing on the output signal from the image sensor control circuit 107 to generate a video signal. The monitor device 109 displays the output signal of the camera signal processing circuit 108 on the screen. The monitor device 109 is used by the photographer to monitor the image, and displays the camera status and various warnings to the photographer.

  The recording device 113 records the video signal generated by the camera signal processing circuit 108 on a recording medium such as a magnetic tape, an optical disk, a magnetic disk, or a semiconductor memory. The zoom drive source 110 is a drive source for moving the zoom lens 102. The focusing drive source 111 is a drive source for moving (position adjustment) the focus lens 105. As the zoom drive source 110 and the focusing drive source 111, a stepping motor, a direct acting voice coil motor, or the like is used.

  The aperture drive source 115 is a drive source for changing the aperture diameter of the aperture 103. As the aperture driving source 115, a stepping motor, a so-called galvano actuator, or the like is used. The filter drive source 119 is a drive source for moving the infrared light removal filter 118 in and out of the optical path of the imaging optical system. Each of the above driving sources is controlled by a driving command from the camera microcomputer 114. Note that the positions of the lens, diaphragm, and filter driven by each of the above-described driving sources are detected by position detection means (not shown) and used for various controls in the camera microcomputer 114. A sensor for detecting the position may be provided as the position detecting means. If a stepping motor is used as a drive source, the camera microcomputer 114 may detect the position by counting the number of drive pulses for driving the stepping motor.

  The camera microcomputer 114 is a microcomputer that controls the operation of the entire imaging apparatus, and various controls related to the present embodiment are also executed by the camera microcomputer 114. The focus signal processing circuit 112 extracts a high frequency component from the video signal generated by the camera signal processing circuit 108 and generates a focus signal. This focus signal represents the sharpness (contrast state) of the captured subject image. The sharpness changes depending on the focus state of the subject image, and as a result, the signal represents the focus state of the subject image.

  When the imaging apparatus is controlled in the autofocus state, the camera microcomputer 114 executes a known automatic focus control process using the focus signal. The execution of the automatic focus control process is a process for driving the focus lens 115 and performing focusing by an automatic focusing operation by the camera microcomputer 114. Taking advantage of the fact that the focus signal has the maximum property when the subject image is in focus, the camera microcomputer 114 detects the change of the focus signal by moving the focus lens 105. Then, the camera microcomputer 114 moves the focus lens 105 to a position where the focus signal is maximized. As a result, the subject image can be focused.

  The memory 116 is a storage unit configured by a DRAM, a flash ROM, or the like. The memory 116 stores a program for processing performed by the camera microcomputer 114, data used in the processing, shooting mode information, and the like. The operation mode selector switch 117 is used to switch the operation mode of the imaging apparatus. Specifically, the shooting mode of the imaging apparatus is switched between the visible light shooting mode and the infrared light shooting mode by operating the operation mode switching switch 117. When the infrared light shooting mode is selected, the camera microcomputer 114 controls the filter drive source 119, the infrared light removal filter 118 is moved out of the optical path of the image pickup optical system, and the image pickup apparatus is moved to the infrared light. Shooting conditions suitable for optical shooting are set. On the other hand, when the visible light imaging mode is selected, the infrared light removal filter 118 is moved on the optical path, and the imaging device is set to imaging conditions suitable for visible light imaging.

  The filter moving means for moving the infrared light removal filter 118 and the operation mode switching means for switching between the visible light photographing mode and the infrared light photographing mode may be used as a common member. That is, the imaging apparatus may include a lever that manually moves the infrared light removal filter 118 in and out of the optical path instead of the filter drive source 119. The photographer operates this lever to move the filter out of the optical path. Then, the movement of the filter may be detected by the camera microcomputer 114 by a filter position detection unit (not shown), and the operation mode may be switched to the infrared light imaging mode.

  On the other hand, when the filter is moved on the optical path by the lever operation, the camera microcomputer 114 switches the operation mode to the visible light photographing mode. According to this configuration, it is not necessary to provide a motor as the filter driving means, and the size and cost of the imaging apparatus can be reduced.

  The auto / manual focus switch 120 is used by the photographer to select an auto focus mode or a manual focus mode. When the autofocus mode is selected, the camera microcomputer 114 executes an autofocus control process. On the other hand, when the manual focus mode is selected, the focus lens 105 is driven by the photographer operating a manual focus operation unit 121 described later. The operation of the manual focus operation unit 121 by the photographer to drive the focus lens 105 to perform focus adjustment (focusing) is referred to as manual focusing operation.

  In the manual focus mode, the focus lens is not driven unless the photographer performs a manual focus operation. Therefore, after the subject image is focused in the autofocus mode, when the photographer wants to maintain the state, the autofocus control can be stopped by switching to the manual focus mode.

  The manual focus operation unit 121 is used when the photographer performs manual focus adjustment in a state where the manual focus mode is selected. Using the manual focus operation unit 121, the operator can specify an infinite direction and a close direction as the focus adjustment directions. When the operator designates the focus adjustment direction as an infinite direction by operating the manual focus operation unit 121, the focus lens 105 is moved in a direction to focus on a distant subject. On the other hand, when the operator operates the focus adjustment direction in the closest direction by operating the manual focus operation unit 121, the focus lens 105 is moved in a direction to focus on a nearby subject. The operating means for manual focus adjustment may be a ring or dial that is rotated in addition to the switch. Generally, the ring or dial can perform finer focus adjustment than the switch.

  The zoom operation unit 122 is used by the photographer to change the zoom magnification. The zoom operation unit 122 is, for example, a switch, a volume key, a ring, or the like. When the photographer designates the zoom direction to the wide angle (wide) direction by operating the zoom operation unit 122, the zoom lens 102 is moved to the wide angle side. When the photographer designates the telephoto (tele) direction, the zoom lens 102 is moved to the telephoto side. Moved.

  Outputs from the auto / manual focus switching switch 120 to the zoom operation unit 122 are input to the camera microcomputer 114, and control processing corresponding to each function is executed by the camera microcomputer 114.

FIG. 2 is a flowchart illustrating the focus adjustment control process when the operation mode is switched from the visible light photographing mode to the infrared light photographing mode in the first embodiment.
First, the camera microcomputer 114 executes various camera control processes executed in the visible light photographing mode. A detailed description of the processing here is omitted. Subsequently, the camera microcomputer 114 reads the position of the zoom lens by the position detection means (step S202). Further, the camera microcomputer 114 reads the position of the focus lens by the position detection means (step S203).

  Next, the camera microcomputer 114 determines whether the manual focus mode (MF mode) is selected (step S204). If the manual focus mode is not selected, the process proceeds to step S207. If the manual focus mode is selected, the process proceeds to step S205.

  In step S205, the camera microcomputer 114 backs up and stores the zoom lens position Z1 in the memory 116. The camera microcomputer 114 backs up and stores the focus lens position F1 in the memory 116 (step S206). The backed-up position information of the zoom lens and focus lens is used to determine the movement destination of the focus lens when switching to the visible light shooting mode after switching to the infrared light shooting mode by the photographer's operation. It is done.

  Next, the camera microcomputer 114 determines whether the shooting mode has been switched from the visible light shooting mode to the infrared light shooting mode (step S207). When the photographing mode is not switched from the visible light photographing mode to the infrared light photographing mode, the process returns to step S201, and the camera microcomputer 114 continues the processing in the visible light photographing mode. If the shooting mode is switched from the visible light shooting mode to the infrared light shooting mode, the process proceeds to step S208.

  In step S208, the camera microcomputer 114 backs up the manual focus / autofocus selection state in the visible light photographing mode. Then, the camera microcomputer 114 switches the shooting mode to the infrared light shooting mode (step S209).

  The processes in steps S210 to S214 are processes corresponding to the characteristic part of the present embodiment. First, the camera microcomputer 114 calculates a correction amount (hereinafter referred to as “position correction amount”) of the focus lens position for correcting a focus change due to the infrared light removal filter being retracted out of the optical path.

  As described above with reference to FIG. 7, when the infrared light removal filter is moved out of the optical path in the visible light environment, the position correction amount of the focus lens for canceling the change in the focus state is as shown in FIG. It becomes a curve L1. Therefore, in this embodiment, for each zoom lens position, the curve L1 in FIG. 7, that is, the position correction amount in the environment of only visible light is stored in advance in the first storage means (memory 116). Then, the camera microcomputer 114 calculates a position correction amount corresponding to the zoom lens position read in step S202 based on the position correction amount stored in the memory 116 (step S210).

  Next, the camera microcomputer 114 functions as a focus correction unit, and moves the focus lens by the position correction amount calculated in step S210 from the current focus lens position (step S211). Thereby, the focus change accompanying the retraction of the infrared light removal filter 118 is canceled. Then, the process proceeds to step S212.

  Next, the camera microcomputer 114 determines whether the imaging mode of the imaging apparatus is the visible light imaging mode and the manual focus mode. If the manual focus mode is set in the visible light photographing mode, the process proceeds to step S213, and if not, the process proceeds to step S215.

  Since the correction amount of the focus lens position changes depending on the component ratio of visible light and infrared light, the focused state cannot be maintained only by correcting the position of the focus lens in step S211. Therefore, in this embodiment, in step S213, the one-shot focus process is executed to detect the in-focus position, thereby maintaining the in-focus state. The one-shot focus process is an automatic focus adjustment process after correcting the focus change due to the retracting of the infrared light removal filter.

  Next, the camera microcomputer 114 switches the shooting mode to the manual focus mode (step S214). Then, the camera microcomputer 114 ends the shooting mode switching process (step S215).

FIG. 3 is a flowchart for explaining the one-shot focus processing in step S213 in FIG.
First, the camera microcomputer 114 sets the start position of the one-shot focus operation to the current focus position (step S301). The current focus position is the previous focus lens position (focus correction position) obtained by moving the focus lens position by the position correction amount in step 211 in FIG.

  The start position of the one-shot focus operation is a drive start position of the focus lens in the one-shot focus operation. In step S301, the camera microcomputer 114 further returns the focus lens to the drive start position in step S307 when the focus position cannot be detected by the one-shot focus operation. Therefore, the drive start position is stored in the memory 116. Make a backup.

  Next, the camera microcomputer 114 sets the drive start direction of the focus lens in the one-shot focus operation (step S302). Specifically, the camera microcomputer 114 determines the drive start direction based on the positional relationship between the focus position in the visible light environment and the focus position in the infrared light environment when the infrared light removal filter is retracted. decide. In the present embodiment, the positional relationship information indicating the positional relationship is stored in advance in the second storage unit (for example, the memory 116 or a storage unit (not shown)). Therefore, the camera microcomputer 114 determines the drive start direction of the focus lens based on the positional relationship indicated by the positional relationship information stored in the second storage unit.

  Next, the camera microcomputer 114 sets the focus lens drive range in the one-shot focus operation (step S303). Similarly to the driving start direction, the camera microcomputer 114 drives the driving range based on the positional relationship between the focus position in the visible light environment and the focus position in the infrared light environment when the infrared light removal filter is retracted. To decide.

  4 and 5 are diagrams for explaining the drive start direction and drive range of the focus lens in the one-shot focus operation. 4 and 5 show the focus position in the state in which the infrared light removal filter is inserted, the focus position in the visible light environment in the state in which the infrared light removal filter is retracted, and in the infrared light environment. The positional relationship with the focus position is schematically shown. In the example illustrated in FIG. 4, the focus position in the visible light environment with the infrared light removal filter retracted is the focus correction that has been performed by moving the focus lens by the position correction amount L1 in order to correct the focus change. Position.

  When the focus position is in the positional relationship shown in FIG. 4A, the camera microcomputer 114 sets the focus lens drive start direction to the focus position direction in the environment of only infrared light, that is, the closest direction. In addition, the camera microcomputer 114 sets the drive range between the focus position in the visible light environment and the focus position in the infrared light environment when the infrared light removal filter is retracted.

  FIG. 4B shows the case where the focus position in the visible light environment and the focus position in the infrared light environment are opposite to those in FIG. 4A, that is, the correction amount L1 and the correction amount L2 in FIG. Indicates the positional relationship when L1 <L2. When the focus position is the positional relationship shown in FIG. 4B, the camera microcomputer 114 sets the drive start direction to an infinite direction. In addition, the camera microcomputer 114 sets the drive range between the focus position in the visible light environment and the focus position in the infrared light environment when the infrared light removal filter is retracted.

  The correction amount of the focus lens position, that is, the focus position varies depending on the component ratio of visible light and infrared light. Therefore, the camera microcomputer 114 starts driving toward the focus position direction in the infrared light environment when the position (focus correction position) moved by the correction amount in the visible light environment is set as the start position of the one-shot focus operation. To do. Thereby, the camera microcomputer 114 searches for a focus position between the focus position in the visible light environment and the focus position in the infrared light environment. As a result, the in-focus position can be detected correctly.

  The camera microcomputer 114 may calculate the depth of focus determined by the aperture value of the aperture 103 and the pixel pitch of the image sensor, and set the driving range based on the calculated depth of focus. For example, if the camera microcomputer 114 sets the driving range to about twice the depth of focus, it will be difficult to see the focus fluttering in the one-shot focus operation, and other subjects may be in focus or out of focus. Can be prevented.

  Returning to the description of FIG. In step S304, the camera microcomputer 114 executes a one-shot focus process. Specifically, the camera microcomputer 114 drives the focus lens based on the drive start position, the drive start direction, and the drive range set in steps S301 to S303, and detects the focus lens position where the focus signal reaches a peak. The camera microcomputer 114 detects the in-focus position by performing a so-called mountain climbing operation. Then, the process proceeds to step S305. Detailed description of the mountain climbing operation is omitted.

  Next, the camera microcomputer 114 determines whether or not the subject image has been focused by the one-shot focus process (step S305). If focusing is complete, the process ends. If focusing has not been completed, the process proceeds to step 306.

  In step S306, the camera microcomputer 114 determines whether the number of executions of the one-shot focus operation is a predetermined number or more. If the number of executions of the one-shot focus operation is less than the predetermined number, the process proceeds to step S307. If the number of executions of the one-shot focus operation is equal to or greater than the predetermined number, the process proceeds to step S308. In the present embodiment, the predetermined number of times is set to two based on the operation time and the focusing performance of the one-shot focus operation when the shooting mode is switched. Note that the one-shot focus operation may be stopped once, or may be repeated until in-focus.

  In step S307, the camera microcomputer 114 expands the focus lens drive range by the one-shot focus operation (step S307), and the process proceeds to step S304. The camera microcomputer 114 may expand the driving range stepwise according to the number of repetitions of the one-shot focus operation. The camera microcomputer 114 expands to the operable range of the focus lens at the second time, and expands at the second time and thereafter. This range may be maintained.

  In step S308, the camera microcomputer 114 determines that the in-focus position has not been detected, and moves the focus lens to the start position of the one-shot focus operation. Then, the process ends (step S309).

  In the first embodiment, the position L in FIG. 7, that is, the position correction amount in the environment of only visible light is stored in the memory, and the position correction amount corresponding to the zoom position is calculated based on the position correction amount ( (S210 in FIG. 2). As a modification of the first embodiment, the position L in FIG. 7, that is, the position correction amount under the environment of only infrared light is stored in the memory 116, and the position correction amount corresponding to the zoom position is based on this position correction amount. May be calculated. That is, in the modification of the first embodiment, the camera microcomputer 114 moves the focus lens to the focus position in the infrared light environment with the infrared light removal filter retracted, and this position is used for the one-shot focus operation. The start position.

  In the modification of the first embodiment, since the position of the focus lens that moves in step S211 in FIG. 2 changes, it is necessary to change the driving start direction and the driving range. When the camera microcomputer 114 moves the focus lens by the position correction amount L2 in FIG. 7 in step S211, the camera microcomputer 114 sets the drive start direction and the drive range as shown in FIG. In the example shown in FIG. 5, the focus position in the infrared light environment with the infrared light removal filter retracted is the focus after the focus lens is moved by the position correction amount L2 in order to correct the focus change. This is the correction position.

  When the focus position has the positional relationship shown in FIG. 5A, the position correction amount L1 in the visible light environment and the position correction amount L2 in the infrared light environment have a relationship of L1> L2. In this case, the camera microcomputer 114 sets the driving start direction of the focus lens to a direction toward the focus position in the visible light environment, that is, an infinite direction. In addition, the camera microcomputer 114 sets the drive range of the focus lens between the focus position in the visible light environment and the focus position in the infrared light environment when the infrared light removal filter is retracted.

  When the focus position has the positional relationship shown in FIG. 5B, the position correction amount L1 and the position correction amount L2 have a relationship of L1 <L2. In this case, the camera microcomputer 114 sets the drive start direction of the focus lens to the closest direction. In addition, the camera microcomputer 114 sets the drive range of the focus lens between the focus position in the visible light environment and the focus position in the infrared light environment when the infrared light removal filter is retracted.

  An intermediate position correction amount between L1 and L2 may be stored in the memory, and the camera microcomputer 114 may calculate a position correction amount corresponding to the zoom position based on the position correction amount. When applying an intermediate position correction amount between L1 and L2, the camera microcomputer 114 detects the balance between visible light and infrared light in the shooting environment from the video signal or the like, and is more likely to be in focus. May be the driving start direction of the focus lens.

  Note that the processing of step S210 and step S211 in FIG. 2 may be omitted, and the camera microcomputer 114 may switch to the autofocus mode without correcting the focus lens position. Even in this case, the image can be brought into focus. However, in this case, since the focus adjustment is executed from a state where the image is largely blurred, it takes time to reach the in-focus state.

  According to the first embodiment described above, the focus adjustment by the autofocus operation when the focus is changed in accordance with the switching to the infrared light photographing mode in the selection state of the visible light photographing mode and the manual focus mode is accurate. And it becomes possible to execute quickly. Therefore, the focused state of the image can be kept good.

(Example 2)
The configuration of the imaging apparatus according to the second embodiment is the same as the configuration illustrated in FIG. In the second embodiment, the camera microcomputer 114 weights the position correction amount so that the focus lens position correction amount stored in advance in the memory is overcorrected or not corrected, or position correction is performed. An arithmetic process for adding an offset amount to the amount is performed. Then, the camera microcomputer 114 performs focus position correction using the position correction amount after the calculation process. Thereby, the camera microcomputer 114 shifts the drive start position of the focus lens in the one-shot focus operation.

FIG. 6 is a flowchart for explaining a focus adjustment control process when the operation mode is switched from the visible light photographing mode to the infrared light photographing mode in the second embodiment.
The processing from step S601 to S609 is the same as the processing from step S201 to S209 in FIG. Further, the processing from step S612 to S615 is the same as the processing from step S212 to S215 in FIG.

  In step S610, the camera microcomputer 114 weights the correction amount so that the pre-stored focus lens position correction amount is overcorrected or insufficiently corrected, or sets the offset amount to the correction amount. An addition operation is performed (step S610). Then, the camera microcomputer 114 moves the focus lens by the amount of the position correction after the calculation in step S610 (step S611). Accordingly, the focus lens position to be moved, that is, the drive start position in the one-shot focus operation can be shifted. At this time, the direction in which the drive start position is shifted is determined depending on which of the position correction amount L1 and the position correction amount L2 is to be corrected and where the drive start direction and the drive range are set.

  In the present embodiment, the camera microcomputer 114 sets the drive range to a range that includes the shift of the drive start position. In this way, the camera microcomputer 114 weights the position correction amount or adds an offset amount to thereby shift the drive start position by a predetermined amount in the direction opposite to the drive start direction of the focus lens. As a result, the in-focus position of the subject that is in focus in the visible light photographing mode is always within the determined driving range and on the driving start direction side. Therefore, the focus position of the same subject can be accurately detected even in the infrared light photographing mode. In addition, since the reverse drive operation or the like when the drive start direction is wrong does not occur, the time until the in-focus position is detected can be shortened. According to the second embodiment described above, the focus adjustment by the one-shot focus operation can be executed more accurately and quickly.

  The present invention has been described in detail based on the preferred embodiments thereof, but the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. A part of the above-described embodiments may be appropriately combined.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

114 Camera microcomputer 118 Infrared light removal filter

Claims (10)

A visible light photographing mode in which an infrared light removing filter is positioned on the optical path of the imaging optical system and photographing using visible light is performed, and the infrared light removing filter is retracted from the optical path of the imaging optical system to perform infrared imaging. An imaging apparatus having an infrared light photographing mode for photographing using light,
When the focus lens is driven and focused in the manual focusing operation in the visible light photographing mode, the infrared light removal filter is retracted when the visible light photographing mode is switched to the infrared light photographing mode. A focus correction means for correcting a focus change caused by
Control means for controlling the driving of the focus lens so as to perform a hill-climbing operation for focus position detection after the focus change is corrected ;
With
The control means is based on a positional relationship between a focus position under a visible light environment and a focus position under an infrared light environment in a state where the infrared light removal filter is retracted from the optical path of the imaging optical system. Dzu rather imaging device and controls the driving of the focus lens to perform hill-climbing operation direction. First storage means in which a position correction amount of the focus lens for correcting the focus change is stored in advance;
Position relationship information indicating a positional relationship between a focus position under a visible light environment in a state where the infrared light removal filter is retracted and a focus position under an infrared light environment is stored in advance. Storage means,
The focus correction unit corrects the focus change by moving the focus lens based on a position correction amount stored in the first storage unit,
The imaging apparatus according to claim 1, wherein the control unit determines a driving start direction of the focus lens based on the positional relationship information stored in the second storage unit. The focus correction unit is determined by the control unit with respect to a position where the focus lens is moved by a position correction amount stored in the first storage unit when the focus change is corrected. The imaging apparatus according to claim 2, wherein the focus lens is moved to a position shifted by a predetermined amount in a direction opposite to a driving start direction of the focus lens. The focus correction unit corrects the focus change by moving the focus lens based on a position correction amount of the focus lens under a visible light environment,
The control means includes
The driving start direction of the focus lens is determined in a direction from a focus position in a visible light environment to a focus position in an infrared light environment when the infrared light removal filter is retracted. Item 4. The imaging device according to any one of Items 1 to 3. The focus correction unit corrects the focus change by moving the focus lens based on a position correction amount of the focus lens under an infrared light environment,
The control means determines the driving start direction of the focus lens in a direction from a focus position in an infrared light environment to a focus position in a visible light environment when the infrared light removal filter is retracted. The imaging apparatus according to any one of claims 1 to 3, wherein The control unit further determines a driving range of the focus lens in the hill-climbing operation based on the positional relationship information stored in the second storage unit. The imaging device according to any one of the above. The control means sets a range between a focus position under a visible light environment and a focus position under an infrared light environment when the infrared light removal filter is retracted as a driving range of the focus lens. The imaging device according to claim 6, wherein the imaging device is determined. Calculating means for calculating a depth of focus of the imaging optical system;
The imaging apparatus according to claim 1, wherein the control unit determines a driving range of the focus lens in the hill-climbing operation based on the calculated depth of focus . 9. The control unit according to claim 6, wherein the control unit expands the drive range of the focus lens in the hill-climbing operation when the focus is not achieved within the determined drive range. 10. The imaging device described in 1. A visible light photographing mode in which an infrared light removing filter is positioned on the optical path of the imaging optical system and photographing using visible light is performed, and the infrared light removing filter is retracted from the optical path of the imaging optical system to perform infrared imaging. A method for controlling an imaging apparatus having an infrared imaging mode for performing imaging using light,
When the focus lens is driven and focused in the manual focusing operation in the visible light photographing mode, the infrared light removal filter is retracted when the visible light photographing mode is switched to the infrared light photographing mode. A focus correction process for correcting the focus change caused by
A control step of controlling the drive of the focus lens so as to perform a hill-climbing operation for focus position detection after the focus change is corrected ;
Have
In the control step, based on a relationship between a focus position in a visible light environment and a focus position in an infrared light environment when the infrared light removal filter is retracted from the optical path of the imaging optical system. A control method characterized by controlling the drive of the focus lens so as to perform a hill-climbing motion in a direction .

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