JP5759120B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus such as a digital camera or a digital video camera, and more particularly to an imaging apparatus capable of both capturing a visible light image and capturing an infrared light image.

  In general, a digital camera or a digital video camera includes a filter that removes an infrared light component from a light component incident on an image sensor from an imaging optical system. This is because the image sensor is also sensitive to infrared light components, so that the color reproducibility of the captured image is reduced due to the mixture of infrared light components, and the resolution is prevented from being lowered due to aberrations. Because.

  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. This is because, in normal shooting with visible light (hereinafter referred to as “visible light shooting mode”), an infrared light removal filter is placed on the optical path for shooting, while in a dark place where there is little visible light, the infrared light removal filter is used for the optical path. Moving outside, it is also possible to shoot with infrared light (hereinafter referred to as infrared light shooting mode).

  By the way, when the infrared light removal filter is taken in and out of the optical path in this way, the focus state of the imaging optical system changes depending on the presence or absence of the infrared light removal filter. For this reason, when the focus lens position for adjusting the focus is switched to the infrared light shooting mode while the subject is focused in the visible light shooting mode, the infrared light removal filter moves out of the optical path. As a result, the subject is out of focus.

  In general, an imaging apparatus has both an autofocus mode in which focus control is automatically performed and a manual focus mode in which a photographer manually performs a focus operation as means for focusing a subject image. It is. When the imaging apparatus is in the autofocus mode, as described above, 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 device is in the manual focus mode, it is necessary to correct the focus lens position so as to cancel the change in the focus state due to the presence or absence of the infrared light removal filter in order to maintain the focused state of the subject. .

  FIG. 8 shows the correction amount of the focus lens position and the zoom lens position when the infrared light removal filter is moved from the optical path to the outside of the optical path in the imaging lens having a zoom lens that changes the magnification of the imaging optical system. It is the figure which showed the relationship. The curve indicated by L1 in the figure is the correction amount of the focus lens position in an environment with only visible light, and the left end in the figure indicates the wide-angle end position of the zoom lens, and the right end indicates the telephoto end position. On the other hand, the curve indicated by L2 in the figure is the correction amount of the focus lens position under the environment of only infrared light, and is greatly different from the curve L1. In an environment where the components of visible light and infrared light are mixed, the correction amount has an intermediate characteristic between L1 and L2. The change in the correction amount according to the component ratio of visible light and infrared light in this way is due to the characteristics of chromatic aberration of the lens of the imaging optical system.

  As described above, the correction amount of the focus lens position changes depending on the component ratio of the visible light and the infrared light, and the visible light environment or the infrared light environment is determined from the ratio of the three primary color signals of the photographed image. A method for discriminating and selecting a correction amount has been proposed (for example, Patent Document 1).

Japanese Patent No. 3982052

  2. Description of the Related Art Recent imaging devices such as digital cameras and digital video cameras have become higher in definition of captured images due to the increase in the number of pixels of an image sensor and the widespread use of high-definition video systems. For this reason, even if the focus lens position shifts slightly, the out-of-focus blur is conspicuous.

  The difference between the focus lens position correction amounts in the visible light environment and the infrared light environment in FIG. 8 is several times to a dozen times larger than the focus lens position shift amount in which the focus blur can be seen. For this reason, as in the above-described prior art, the error in the correction amount is large only by determining whether it is the visible light environment or the infrared light environment from the ratio of the three primary color signals, and the focus state due to the presence or absence of the infrared light removal filter is large. Changes cannot be fully offset. As a result, when the manual focus mode is set while the subject is in focus 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. there were.

  The present invention has been made in view of the above-described problems, and its purpose is to change the focus state of an image even when the manual focus mode is selected in the visible light photographing mode and the infrared light photographing mode is switched. It is to keep it good.

An image pickup apparatus according to the present invention includes an image pickup device that picks up a subject image, a focus lens, an image pickup optical system that guides light of the subject image to the image pickup device, and light incident on the image pickup device. A visible light mode for imaging by placing an infrared light removal filter for removing infrared light components on the optical path of the imaging optical system, and retracting the infrared light removal filter from the optical path of the imaging optical system A mode switching unit that switches between infrared light modes for performing imaging, an autofocus unit that performs focus adjustment by moving the focus lens based on an output signal obtained from the imaging element, and a focus operation unit by a photographer. Manual focus means for moving the focus lens based on the operation, auto focus means and manual focus means are switched off. Storing a switching means, in a state where the visible light mode in the manual focusing means is selected, the position of the focus lens in the visible light mode before being switched from the visible light mode to the infrared light mode to obtain When switching from the state in which the manual focus unit is selected in the visible light mode to the infrared light mode, focus adjustment is performed by the autofocus unit, and the infrared light mode is resumed from the infrared light mode. When the mode is switched to the visible light mode , the focus lens is moved to the position of the focus lens in the visible light mode before switching from the visible light mode stored in the storage unit to the infrared light mode. And control means for controlling so as to

  According to the present invention, even when the manual focus mode is selected in the visible light photographing mode and the infrared light photographing mode is switched, the focused state of the image can be kept good.

1 is a block diagram illustrating a configuration of an imaging apparatus according to a first embodiment of the present invention. 5 is a flowchart showing a switching process from a visible light photographing mode to an infrared light photographing mode according to the first embodiment of the present invention. 6 is a flowchart showing a switching process from the infrared light photographing mode to the visible light photographing mode according to the first embodiment of the present invention. The figure which shows the example of the electronic cam locus | trajectory in a rear focus lens system. The figure which shows a focus lens position correction calculation. 6 is a flowchart illustrating processing when power is turned on for the imaging apparatus. The flowchart which shows the switching process from visible light imaging | photography mode in the 2nd Embodiment of this invention to infrared light imaging | photography mode. The figure which shows the example of the correction amount of a focus lens position when moving an infrared light removal filter out of an optical path.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of a video camera (imaging device) according to the first embodiment of the present invention. In FIG. 1, 101 is a fixed first lens group, 102 is a variable power lens for zooming (hereinafter referred to as a zoom lens), 103 is a stop, 104 is a fixed second lens group, and 105 is a focal plane associated with zooming. It is a focus lens (hereinafter referred to as a focus lens) that has both a function of correcting movement and a function of focusing. An imaging optical system that forms an image of incident light is configured by these. Reference numeral 118 denotes an infrared light removal filter that removes infrared light components, and can be retracted out of the optical path of the imaging optical system by a drive mechanism (not shown). Reference numeral 106 denotes an image sensor such as a CCD sensor or a CMOS sensor, and 107 denotes an image sensor control circuit that controls the operation of the image sensor 106 and samples the output of the image sensor 106. A camera signal processing circuit 108 performs various image processing on the output signal from the image sensor control circuit 107 to generate a video signal. Reference numeral 109 denotes a monitor device, which is a display means. The output signal of the camera signal processing circuit 108 is displayed and used by the photographer to monitor the image, and also displays the camera status and various warnings to the photographer. A 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.

  Reference numeral 110 denotes a motor as a drive source for moving the zoom lens 102, and 111 denotes a motor as a drive source for moving (position adjustment) the focus lens 105, such as a stepping motor or a direct-acting voice coil motor. Is used. Reference numeral 115 denotes a drive source for changing the aperture diameter of the diaphragm 103, and a stepping motor, a so-called galvano actuator, or the like is used. Reference numeral 119 denotes a motor which 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 a camera microcomputer 114 described later. 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. As the position detection means, a sensor for detecting the position may be provided. If a stepping motor is used as a drive source, the camera microcomputer 114 counts the number of drive pulses for driving the stepping motor. The position may be detected by.

  The camera microcomputer 114 is a microcomputer that controls the operation of the entire video camera, and various controls related to this embodiment are also executed by this microcomputer.

  A focus signal processing circuit 112 generates a focus signal by extracting a high frequency component from the video signal generated by the camera signal processing circuit 108. This focus signal represents the sharpness (contrast state) of the captured subject image, but 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 video camera is controlled in an autofocus state, a known autofocus control process is executed by the camera microcomputer 114 using this focus signal. In other words, using the fact that the focus signal has the property of being maximized when the subject image is in focus, the focus lens 105 is moved to detect the change of the focus signal, and the focus signal is at the position where the focus signal is maximized. The focus lens 105 is moved. As a result, the subject image can be focused.

  Reference numeral 116 denotes a memory that is a storage unit configured by a DRAM, a flash ROM, or the like, and stores a program for processing performed by the camera microcomputer 114, data used in the processing, shooting mode information, and the like. Reference numeral 117 denotes an operation mode switch, which is operated when the photographer switches between the visible light photographing mode and the infrared light photographing mode. 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. In the above description, the infrared light removal filter 118 is moved by the filter drive source 119 in accordance with the switching of the operation mode changeover switch. However, the filter moving means and the operation mode switching means are defined as a common member as follows. It is good also as composition to do. That is, instead of the filter drive source 119, a lever or the like for manually moving the infrared light removal filter 118 in and out of the optical path is provided, and the photographer operates the lever to move the filter out of the optical path. The movement of the filter is detected by the camera microcomputer 114 by a filter position detection means (not shown), and the operation mode is switched to the infrared light photographing mode. Conversely, when the filter is moved on the optical path by lever operation, the operation mode is switched to the visible light photographing mode. In this way, 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.

  An auto / manual focus switching switch 120 is operated when the photographer selects the auto focus mode or the manual focus mode. When the autofocus mode is selected, the above-described autofocus control process is executed by the camera microcomputer 114. On the other hand, when the manual focus mode is selected, the focus lens 105 is driven by a photographer operating manual focus operation means described later, and manual focus adjustment can be performed. 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.

  A manual focus operation unit 121 is operated when the photographer performs manual focus adjustment in a state where the manual focus mode is selected. As the direction of focus adjustment, an infinite direction and a close direction can be designated. When operated in the infinite direction, the focus lens 105 is moved in a direction to focus on a distant subject. On the other hand, when operated in the close-up direction, the focus lens 105 is moved in the direction of focusing on a near subject. The operating means may be a ring or a dial that is rotated in addition to the switch, and generally the ring or dial can perform finer focus adjustment than the switch.

  Reference numeral 122 denotes a zoom operation unit for the photographer to change the zoom magnification, and switches, volume keys, rings, and the like are used. When the photographer operates in the wide angle (wide) direction, the zoom lens 102 is moved to the wide angle side, and when operated in the telephoto (tele) direction, the zoom lens 102 is moved to the telephoto side. Although details will be described later, the focus lens 105 is also moved so as to follow a predetermined locus in accordance with the movement of the zoom lens 102 in order to correct the movement of the focal plane accompanying the zooming.

  Outputs from the switches 120 to 122 and the operation unit are input to the camera microcomputer 114, and control processing corresponding to each function is executed by the camera microcomputer 114.

  Next, a focus adjustment control process when the operation mode is switched from the visible light photographing mode to the infrared light photographing mode, which is a feature of the present embodiment, will be described with reference to the flowchart of FIG.

  In FIG. 2, in Step 101, various camera control processes executed in the visible light photographing mode of the video camera are performed. A detailed description of the processing here is omitted. Next, in Step 102 and Step 103, the positions of the zoom lens and the focus lens are read from the position detection means, respectively.

  Next, in Step 104, it is determined whether or not the manual focus mode is selected. If it is determined that the manual focus mode is not selected, the process proceeds to Step 107. On the other hand, if it is determined that the manual focus mode is selected, the zoom lens position Z1 and the focus lens position F1 are backed up and stored in the memory 116 in Step 105 and Step 106, respectively, and the process proceeds to Step 107. The position information of the zoom lens and focus lens backed up here is the movement of the focus lens when switched to the infrared light shooting mode after switching to the infrared light shooting mode by the photographer as described later. Used to determine the destination.

  In Step 107, it is determined whether or not the photographer has switched to the infrared light photographing mode. If it is determined that the mode has not been switched, the process returns to Step 101 to continue the processing in the visible light imaging mode. On the other hand, if it is determined that the mode has been switched to the infrared light shooting mode, the process proceeds to Step 108 to back up the manual focus / autofocus selection state in the visible light shooting mode. Then, the process proceeds to Step 109, the video camera is switched to the infrared light photographing mode, and the process proceeds to Step 110.

  Step 110 to Step 112 are the features that characterize this embodiment. First, in Step 110, a correction amount (position correction amount) of the focus lens position when the infrared light removal filter moves out of the optical path is calculated. As described above, when the infrared light removal filter is moved out of the optical path in an environment with only visible light, the correction amount of the focus lens position for canceling the change in the focus state is L1 in FIG. Therefore, the correction amount of the focus lens for each zoom lens position corresponding to L1 in FIG. 8 is stored in advance in a nonvolatile memory, and the correction amount of the focus lens position is set based on the zoom lens position read in Step 102. Calculate with Next, in Step 111, the focus lens is moved from the current focus lens position by the correction amount calculated in Step 110, and the change in the focus state is canceled. However, as described above, 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 the correction here. Therefore, in step 112, the video camera is switched to the autofocus mode. Thereby, the focus adjustment by the autofocus operation is executed, and the image can be brought into a focused state. Thereafter, the process proceeds to Step 113, and the photographing mode switching process is terminated. The video camera is switched to the auto focus mode by the above switching process. However, if the manual focus mode is selected again by the photographer's operation, the manual focus mode can be set even during the infrared light shooting mode. it can.

  In the above description, in order to calculate the correction amount of the focus lens, L1 in FIG. 8, that is, the correction amount in the environment of only visible light is stored, but L2 in FIG. It is also possible to store a correction amount under the above environment or an intermediate correction amount between L1 and L2.

  Even if Step 110 and Step 111 are omitted and the focus lens position is not corrected and the mode is switched to the auto focus mode, the image can be brought into a focused state. 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.

  Next, focus adjustment control processing when the operation mode is switched from the infrared light photographing mode to the visible light photographing mode will be described with reference to the flowchart of FIG.

  In FIG. 3, in Step 201, various camera control processes executed in the infrared light photographing mode of the video camera are performed. A detailed description of the processing here is omitted. Next, in Step 202, it is determined whether or not the photographer has switched to the visible light photographing mode. If it is determined that the switch has not been made, the process returns to Step 201 to continue the processing in the infrared light photographing mode. On the other hand, if it is determined that the mode has been switched to the visible light shooting mode, the process proceeds to Step 203, the video camera is switched to the visible light shooting mode, and the process proceeds to Step 204.

  Step 204 to Step 209 are features of the present embodiment. When the manual focus is selected in the visible light photographing mode and the infrared light photographing mode is switched, the visible light photographing mode is switched again. In addition, the lens is returned to the focus position in the previous visible light photographing mode.

  First, in Step 204, the manual focus / autofocus selection state in the previous visible light photographing mode is read from the backed up data, and it is determined whether or not manual focus has been selected. If it is determined that the autofocus mode is set, the process proceeds to Step 210, and the photographing mode switching process is terminated. On the other hand, when it is determined that the manual focus mode is set, the process proceeds to step 205, and processing for returning the lens to the focus position in the previous visible light photographing mode state is executed as described below.

  In Step 205, the zoom lens position is read from the position detection means. Next, in Step 206, the zoom lens position read in Step 205 and the zoom lens position Z1 backed up in Step 105 of FIG. 2 and stored in the memory 116 are compared to determine whether they are equal. When the photographer does not operate the zoom operation unit in the infrared light shooting mode, the zoom lens positions compared here are equal. In this case, the process proceeds to Step 207, and the focus backed up at Step 106 in FIG. The focus lens is moved to the lens position F1 and stopped. Thereafter, the process proceeds to Step 210, and the photographing mode switching process is terminated. With the above processing, the in-focus state in the visible light photographing mode can be made the same as in the previous visible light photographing mode.

  On the other hand, when the photographer operates the zoom operation unit in the infrared light shooting mode, it is determined that the zoom lens positions compared in Step 206 are different. In that case, the process proceeds to Step 208, and the focus lens position correction calculation with respect to the zoom for correcting the movement of the focal plane accompanying the zooming is executed with respect to the backed up focus lens position. Details of the contents of the calculation here will be described later. In Step 209, the focus lens is moved to the correction position of the focus lens calculated in Step 208 and stopped. Thereafter, the process proceeds to Step 210, and the photographing mode switching process is terminated. In this way, even if the zoom lens position is different from the previous visible light photographing mode, the focus lens is returned to the position where the movement of the focal plane due to zooming is corrected with respect to the backed up focus lens position. Thereby, the in-focus state can be made substantially the same as in the previous visible light photographing mode.

  Next, the focus lens position correction calculation executed in Step 208 will be described with reference to FIGS. 4 and 5.

  A lens system in which a focus lens 105 that performs focus adjustment on the imaging surface side of the diaphragm 103 as shown in FIG. 1 is called a rear focus type. In such a lens system, the focal plane moves with zooming. That is, even if the subject distance is the same, if the focal length, that is, the position of the zoom lens 102 is different, the position of the focus lens 105 for focusing the subject image on the imaging surface of the imaging element 106 is different. When the focal length (position of the zoom lens 102) is changed at each subject distance, the position of the focus lens 105 for focusing the subject image on the imaging surface is continuously plotted as shown in FIG. In an imaging apparatus equipped with a rear focus type lens system, information on the plurality of trajectories (also referred to as electronic cam trajectories) or information corresponding thereto (that is, information indicating the trajectories themselves, using the lens position as a variable) In general, a locus is selected based on the positions of the focus lens and the zoom lens, and zooming is performed while following the selected locus.

  As described above, in the rear focus type lens system, the focal plane moves with zooming, and thus a focus lens position correction calculation is required to correct this. This correction calculation will be described below with reference to FIG.

  FIG. 5 shows only an electronic cam trajectory with a specific subject distance (for example, 5 m) extracted from FIG. Assume that the video camera (imaging device) in this embodiment is in the visible light photographing mode, the zoom lens position is the position of Z1 in FIG. 5, the manual focus state is selected, and the subject distance at that time is 5 m. . At this time, the zoom lens position Z1 is backed up at Step 105 in FIG. 2, and the focus position F1 is backed up at Step 106. Thereafter, the photographer switches to the infrared light photographing mode, and the zoom position is changed to the position Z2 in FIG. 5 by the photographer's zoom operation in the infrared light photographing mode.

  Thereafter, when switching to the visible light photographing mode is performed again, the switching processing to the visible light photographing mode described with reference to FIG. 3 is executed. At this time, in Step 206 of FIG. 3, the backed-up zoom lens position Z1 is compared with the current zoom lens position Z2, and since Z1 ≠ Z2, focus lens position correction calculation is executed in Step 208.

  In this calculation, first, based on the backed-up zoom lens position Z1 and focus lens position F1, the electronic cam locus L passing through the point P1 determined from (Z1, F1) is specified. Then, on the electronic cam locus L, the focus lens position F2 at the point P2 where the zoom lens position is Z2 is calculated. These calculations can be easily performed by applying a known interpolation calculation using the electronic cam trajectory information stored in the imaging device as described above. By this calculation, it is possible to calculate the focus lens correction position F2 for correcting the focal plane change due to the change of the zoom lens position from Z1 to Z2.

  The above is the focus lens position correction calculation executed in Step 208 of FIG. By moving the focus lens to the focus lens correction position F2 calculated here at Step 209, the focus state is changed to the previous visible light photographing even if the zoom lens position is different from the previous visible light photographing mode. It can be almost the same as in the mode.

  Next, processing when the video camera is turned off and when the power is turned on will be described below. When the operation mode switching switch is a slide switch or a lever, the visible light photographing mode and the infrared light photographing mode can be switched even when the video camera is not turned on. Even in such a case, the following processing is performed when the power is turned off and when the power is turned on so that the focus adjustment control processing described above can be performed correctly.

  First, when the power is turned off, the photographing mode at the time of turning off the power (whether visible light photographing mode or infrared light photographing mode), the zoom lens and the focus lens position, and the visible light photographing mode backed up at Step 105, Step 106, and Step 108 in FIG. The process of storing the time state data in a non-volatile memory (such as a battery or a RAM held in power by a lithium button battery) is performed.

  Processing at power-on will be described with reference to the flowchart of FIG. First, in Step 301, a general video camera activation process is executed. A detailed description of the processing here is omitted. Next, in Step 302, based on the data stored in the memory, the zoom lens is returned to the position when the power is shut off, and the process proceeds to Step 303.

  In Step 303, it is determined whether or not the video camera is in a manual focus selection state. If it is determined that the autofocus mode is selected, the process proceeds to step 304, the focus lens is returned to the position at the time of power-off, the process proceeds to step 308, and the activation process is terminated.

  On the other hand, if it is determined in step 303 that the manual focus mode is selected, the process proceeds to step 305. In Step 305, it is determined whether or not the shooting mode at startup is the visible light shooting mode. If it is determined that the mode is the visible light shooting mode, the process proceeds to Step 306, and it is determined based on the data stored in the memory whether the shooting mode at the time of power-off is the visible light shooting mode. If it is determined that the mode is the visible light shooting mode, the shooting mode at the time of power-off is the same as that at the time of power-up, so the process proceeds to Step 304 to return the focus lens to the position at the time of power-off, and then proceeds to Step 308. End the startup process. On the other hand, if it is determined in Step 306 that the shooting mode when the power is shut off is the infrared light shooting mode, the shooting mode is switched from the infrared light shooting mode to the visible light shooting mode during the power shutdown. The process proceeds to Step 307.

  Since the processing from Step 307 to Step 310 is the same as Step 206 to Step 209 in FIG. 3 described above, detailed description thereof will be omitted. Here, based on the data in the state of the previous visible light photographing mode backed up at the time of power-off, the same processing as when switching from the infrared light photographing mode to the visible light photographing mode is performed, and Step 308 is performed. Proceed to finish the startup process.

  If it is determined in Step 305 that the shooting mode at startup is the infrared shooting mode, the process proceeds to Step 311, and the shooting mode at the time of power-off is the infrared shooting mode based on the data stored in the memory. Determine if there was. If it is determined that the mode is the infrared light shooting mode, the shooting mode is the same when the power is turned off and the power is turned on. End the startup process with. On the other hand, if it is determined in Step 311 that the shooting mode at the time of power-off is the visible light shooting mode, the shooting mode is switched from the visible light shooting mode to the infrared light shooting mode during power-off. Proceed to Step 312.

  Since the processing from Step 312 to Step 314 is the same as Step 110 to Step 112 in FIG. 2 described above, detailed description thereof is omitted. Here, the correction of the focus lens position and the switching to the auto focus mode are executed based on the focus lens position at the time of power-off in the same manner as when the visible light photographing mode is switched to the infrared light photographing mode. Then, it progresses to Step308 and complete | finishes a starting process.

  By executing the processing described above when the imaging device is turned off and turned on, even if the video camera is not turned on, the visible light imaging mode and the infrared light photography mode are switched. The focus adjustment control process according to the embodiment can be performed correctly.

  According to the first embodiment of the present invention described above, when the manual focus mode is selected in the visible light photographing mode, the infrared light removing filter is switched to the infrared light photographing mode and the infrared light removal filter is out of the optical path. Even if the focus position of the optical system is changed by moving the focus, the focus state of the image can be kept good by performing the focus adjustment by the autofocus operation.

  In addition, after switching to the infrared light shooting mode, when returning to the visible light shooting mode again, the focus lens is returned to the position in the previous visible light shooting mode, so the focus state in the visible light shooting mode is changed. It can be the same as the previous time. Even if the zoom lens position changes at that time, the focus lens is returned to the position where the focal plane change due to zooming is corrected, so the focus state is almost the same as in the previous visible light shooting mode state. can do.

  In addition, even if the video camera is turned off and the visible light mode and infrared light mode are switched, the switching operation with the power turned on is based on the data backed up when the power is turned off. Can be realized.

(Second Embodiment)
The second embodiment of the present invention will be described below. The configuration of the imaging apparatus is the same as that of the first embodiment shown in FIG. In the second embodiment described below, after switching to the infrared light shooting mode with the manual focus mode selected in the visible light shooting mode, after focusing on the subject by the autofocus operation, Operate to shift to manual focus mode.

  FIG. 7 is a flowchart showing a switching process from the visible light photographing mode to the infrared light photographing mode in the second embodiment. Here, Steps 401 to 412 are the same as Steps 101 to 112 in the flowchart of FIG. 2 in the first embodiment, and a description thereof will be omitted.

  In Step 413, it is determined based on the data backed up in Step 408 whether the manual focus mode has been selected in the visible light photographing mode before switching to the infrared light photographing mode. If it is determined that the mode is the autofocus mode, the process proceeds to Step 416, and the photographing mode switching process is terminated.

  On the other hand, if it is determined that the manual focus mode has been selected, the process proceeds to Step 414. In Step 414, it is determined whether or not focusing of the subject image by autofocus control is completed. If focusing is not complete, the autofocus control process is continued. On the other hand, if it is determined that focusing is complete, the process proceeds to Step 415. In Step 415, the video camera is switched to the manual focus mode, and the process proceeds to Step 416 to end the shooting mode switching process.

  By executing the above processing, even when the manual focus mode is selected in the visible light shooting mode and the infrared light shooting mode is switched, the manual focus mode is shifted to after focusing by the autofocus operation. Can be. Thereby, it is possible to keep the focused state of the image good while maintaining the state where the manual focus mode is selected before and after the switching of the photographing mode.

  Since the switching process from the infrared light photographing mode to the visible light photographing mode and the process at the time of power-off are the same as those in the first embodiment described above, description thereof will be omitted. In addition, regarding the process at power-on, in the flowchart of FIG. 6 described in the first embodiment, the above-described power is turned on by adding the process from Step 413 to Step 415 of FIG. 7 between Step 314 and Step 308. An operation similar to the switching operation in the state can be realized.

  According to the second embodiment of the present invention described above, when the manual focus mode is selected in the state of the visible light photographing mode, the focus by the autofocus operation is switched to the infrared light photographing mode. Later, it shifts to manual focus mode. As a result, the state in which the manual focus mode is selected can be maintained even after the shooting mode is switched.

  Although the present invention has been described in detail based on preferred embodiments thereof, 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.

  The present invention also includes a software program that realizes the functions of the above-described embodiments.

Claims (7)

An image sensor for capturing a subject image;
An imaging optical system that includes a focus lens and guides light of the subject image to the imaging device;
A visible light mode for performing imaging by positioning an infrared light removal filter for removing an infrared light component contained in light incident on the image sensor on an optical path of the imaging optical system; and the infrared light removal filter Mode switching means for switching between an infrared light mode for performing imaging by retracting from the optical path of the imaging optical system;
Auto focus means for adjusting the focus by moving the focus lens based on an output signal obtained from the image sensor;
Manual focus means for moving the focus lens based on the operation of the focus operation unit by the photographer;
Switching means for switching between the autofocus means and the manual focus means;
Storage means for storing the position of the focus lens in the visible light mode before switching from the visible light mode to the infrared light mode in a state where the manual focus means is selected in the visible light mode ;
When the manual focus means is switched to the infrared light mode from the state in which the manual focus means is selected in the visible light mode, focus adjustment is performed by the autofocus means, and the infrared light mode is changed to the visible light mode again. Control is performed to move the focus lens to the position of the focus lens in the visible light mode before switching from the visible light mode stored in the storage unit to the infrared light mode when switched. Control means to
An imaging apparatus comprising: An image sensor for capturing a subject image;
An imaging optical system that includes a zoom lens that changes a magnification ratio and a focus lens, and that guides light of the subject image to the imaging device;
A visible light mode for performing imaging by positioning an infrared light removal filter for removing an infrared light component contained in light incident on the image sensor on an optical path of the imaging optical system; and the infrared light removal filter Mode switching means for switching between an infrared light mode for performing imaging by retracting from the optical path of the imaging optical system;
Auto focus means for adjusting the focus by moving the focus lens based on an output signal obtained from the image sensor;
Manual focus means for moving the focus lens based on the operation of the focus operation unit by the photographer;
Switching means for switching between the autofocus means and the manual focus means;
Storage means for storing the position of the focus lens in the visible light mode before switching from the visible light mode to the infrared light mode in a state where the manual focus means is selected in the visible light mode;
When the manual focus means is switched to the infrared light mode from the state in which the manual focus means is selected in the visible light mode, focus adjustment is performed by the autofocus means, and the infrared light mode is changed to the visible light mode again. When switched, the focus lens is moved based on the position of the focus lens in the visible light mode before switching from the visible light mode stored in the storage unit to the infrared light mode. And control means for controlling ,
The storage means stores a position of the zoom lens in the visible light mode before switching from the visible light mode to the infrared light mode in a state where the manual focus means is selected in the visible light mode. ,
When the control means is switched from the visible light mode to the infrared light mode and then switched to the visible light mode again, the position of the zoom lens when the mode is switched to the visible light mode is When the position of the zoom lens in the visible light mode before switching from the visible light mode stored in the storage means to the infrared light mode is different, the visible light stored in the storage means The position of the zoom lens in the visible light mode before switching from the mode to the infrared light mode, in the visible light mode before switching from the visible light mode stored in the storage means to the infrared light mode Based on the position of the focus lens and the position of the zoom lens when switched to the visible light mode, Get the correct position of the focus lens for correcting the change in the focus position of the subject image due to a change in position of Murenzu, shooting you and moving the focus lens to the correct position of the acquired focusing lens Image device. Electronic cam trajectory storage means for storing electronic cam trajectory information indicating the relationship between the position of the zoom lens with respect to one or more subject distances in the imaging optical system and the position of the focus lens focused on the subject distance;
The control means specifies an electronic cam locus corresponding to the position of the zoom lens stored in the storage means and the position of the focus lens stored in the storage means, and the electronic cam locus on the specified electronic cam locus The imaging apparatus according to claim 2 , wherein the correction position of the focus lens is obtained by acquiring the position of the focus lens corresponding to the position of the zoom lens when switched to the visible light mode. The control means moves the focus lens by the autofocus means when the manual focus means is switched from the state in which the manual focus means is selected in the visible light mode, and then moves the manual focus. the imaging apparatus according to any one of claims 1 to 3, characterized in that shifting to state movement takes place of the focus lens based on the operation of the focus operation unit by the photographer by means. The storage means stores information on a mode when the imaging apparatus is powered off,
The control means turns off the power of the imaging apparatus while the manual focus means is selected in the visible light mode and switches on the imaging apparatus again after switching to the infrared light mode. If it is determined that the mode is switched from the visible light mode to the infrared light mode based on the mode information stored in the storage means when the power is turned off, the focus lens is moved by the autofocus means. the imaging apparatus according to any one of claims 1 to 4, characterized in that to perform. The storage means stores the position of the focus lens when the imaging apparatus is powered off,
The control means is switched to the infrared light mode in a state where the manual focus means is selected in the visible light mode, the power source of the imaging device is shut off, and further switched to the visible light mode. When the power of the image pickup apparatus is turned on after being made, the focus lens is moved based on the mode information at the time of power-off stored in the storage means and the position information of the focus lens. The imaging device according to claim 5 . The storage means stores information for correcting a focus position shift between when the infrared light removal filter is located on the optical path of the imaging optical system and when the infrared light removal filter is retracted from the optical path,
The control means detects the shift of the focus position stored in the storage means when the manual focus means is selected in the visible light mode and is switched to the infrared light mode. after correcting the position of the focus lens based on the information for correcting imaging apparatus according to any one of claims 1 to 6, characterized in that the movement of the focus lens by said automatic focusing means .

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