JP6594053B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus having focus control.

  When monitoring using a conventional surveillance camera that can capture infrared light, the visible light and infrared light have different wavelengths, so a shift occurs between the focal plane of visible light and the focal plane of infrared light, and the focus position May have been different.

  In Patent Document 1, as a technique for imaging a wide wavelength region from visible light to infrared light, by using a diaphragm including a visible light cut filter in addition to a normal diaphragm, by adjusting the visible light component to be transmitted In order to alleviate the focus shift, disclosed is one.

JP2008-268868

  However, in the prior art disclosed in the above-mentioned patent document, only one of visible light and infrared light can be used for imaging. In addition, depending on whether visible light or infrared light is imaged, an aperture including a visible light cut filter needs to be added and controlled, which is cumbersome for the user.

  Therefore, an object of the present invention is to provide an image focused on a target subject in either wavelength region when imaging two wavelength regions of visible light and infrared light with the configuration of a conventional imaging device. That is.

In order to achieve the above object, the present invention is an imaging apparatus having an optical unit for forming a subject image, the focus adjustment means for adjusting the focus position of the optical unit, and the aperture diameter of the optical unit. The aperture adjustment means for adjusting, and the optical section includes a reflection section that reflects either an infrared light component or a visible light component included in the subject image, and controls the focus adjustment means and the aperture adjustment means. and a control unit, and an infrared light imaging means for imaging the pre Kiaka outside light component through the diaphragm of the optical unit, and the visible light imaging means for imaging the pre-listen visible light component through the diaphragm of the optical portion, The infrared light imaging means and the visible light imaging means can capture images in parallel, and the control means can focus on the other focus based on one focus position of the infrared light imaging means and the visible light imaging means. The position is within the depth of field. And controlling said focus adjusting means and throttle adjusting means so.

  According to the present invention, when imaging is performed using two wavelength regions of visible light and infrared light with a configuration of a conventional imaging device, an image focused on a target subject in both wavelength regions is provided. That is.

1 is a block diagram illustrating a configuration of an example of an imaging apparatus according to a first embodiment of the present invention. FIG. 6 is a diagram for explaining focus control in the first embodiment. 6 is a flowchart for explaining an operation when a user requests to change an aperture value according to the first exemplary embodiment. 6 is a flowchart for explaining switching to a common use mode by a schedule function according to the first embodiment. 6 is a flowchart for explaining switching to a preferential use mode by a schedule function according to the first embodiment. 6 is a flowchart for explaining switching to a priority use mode based on a detected luminance value according to the first embodiment. 6 is a flowchart for explaining switching to a common use mode based on a detected luminance value according to the first embodiment. FIG. 6 is a diagram illustrating an example of a setting table for aperture values corresponding to a wavelength region to be imaged in the first embodiment. It is a block diagram which shows the structure about an example of the imaging device in 2nd Example of this invention. FIG. 10 is a diagram for explaining focus control in Embodiment 2. 12 is a flowchart for explaining an operation when a user requests to change an aperture value in the second embodiment. FIG. 10 is a diagram illustrating an example of a setting table for aperture values corresponding to the wavelength characteristics of the image sensor according to the second embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

Example 1
FIG. 1 is a block diagram illustrating an example of a basic configuration of an imaging apparatus according to the first embodiment of the present invention. A subject image (not shown) passes through the infrared filter 101 via the imaging optical system 100 and enters the image sensor 102 such as a CCD or CMOS sensor. In FIG. 1, the imaging optical system 100 is represented by a single lens, but is usually configured to include a plurality of lenses. In addition, the imaging optical system 100 includes a diaphragm mechanism for controlling the amount of incident light. In this embodiment, the imaging optical system 100 and the infrared filter 101 correspond to an optical unit for capturing a subject image.

  The imaging optical system control unit 106 performs mechanical driving related to focus control, zoom control, aperture control, and the like included in the imaging optical system 100.

  The infrared filter 101 is disposed so as to be insertable / removable between the image pickup optical system 100 and the image pickup element 102, and this insertion / extraction control is controlled by the infrared device control unit 107. The infrared filter is a transmission unit that attenuates infrared light and transmits visible light, and is automatically inserted and extracted according to a user instruction or subject brightness. Further, the infrared device control unit 107 may include an infrared illumination (not shown). In the present embodiment, the imaging unit including the imaging element 102 and the infrared filter 101 corresponds to a visible light imaging unit that captures a visible light component included in the subject image. In the present embodiment, the imaging unit with the infrared filter 101 removed corresponds to an infrared light imaging unit that captures an infrared light component included in the subject image.

  The subject image formed on the image sensor 102 is converted into an image signal and input to the image processing unit 103. The image input to the image processing unit 103 is subjected to predetermined image processing such as gamma correction and color balance adjustment, and an image file such as JPEG is generated.

  The output image processed by the image processing unit 103 is displayed on the display unit 104 after predetermined display processing is performed. In addition, the user can operate and request the imaging apparatus by operating a UI displayed on the display unit 104. Note that. In order to operate the UI displayed on the display unit 104, an operation unit (not shown) may be used.

  Each of the above blocks is controlled by the system controller 105.

  The system controller 105 includes a CPU that controls the system. Specifically, the system controller 105 sets control instructions and parameters for each block. Further, the system controller 105 stores the result processed by each block in a memory (not shown), performs an operation, and outputs the result to each block. The memory is used as a storage area for various data such as a program storage area executed by the system controller 105, a work area during program execution, and unnecessary light generation conditions.

  Further, the system controller 105 acquires focus information from the image processing unit 103 in order to perform focus control performed by the imaging optical system control unit 106. Based on the acquired information, the system controller 105 sends a command to the imaging optical system control unit 106 in order to move the imaging optical system 100 to a focused position. In general, the focus information is information obtained by performing focus adjustment by a method such as contrast AF and phase difference AF, which is a function called autofocus (AF) for performing automatic focusing.

  Contrast AF is a method that creates a signal from the contrast of the video and uses the high-frequency component to focus, and phase difference AF divides the image that has entered from the lens into two, and adjusts the focus position from the imaging interval. It is a method.

  A mode in which focus control is performed so as to focus on any of different wavelength regions (hereinafter, sometimes referred to as a common use mode) will be described with reference to FIG. In addition, a mode for controlling the common use mode so that a certain wavelength region is in focus is referred to as a priority use mode below.

  200 indicated by a solid line is the focus position of the imaging apparatus, and 201 indicated by an arrow indicates the depth of field (depth of focus) of the imaging apparatus. 202 is a focus position when imaged in the visible light region, and 203 is a focus position when imaged in the infrared light region. FIG. 2A shows the preferential use mode. That is, the focus position 200 of the imaging apparatus is set to the focus position 202 in the visible light region. For this reason, the visible light region is in focus, but the infrared light region is out of focus because the in-focus position 203 is located outside the depth of field.

  On the other hand, in the common use mode, the imaging optical system 100 is controlled so that the depth of field 201 covers the in-focus position 203 in the infrared light region, and the aperture value is increased, so that FIG. The depth of field is extended to the depth of field 204 indicated by the dotted line in FIG. When changing the aperture value, a setting table as shown in FIG. 8 is prepared for the combination of wavelength regions to be focused in advance, and the system controller 105 can change the aperture value based on the setting table. Good. As a result, it is possible to acquire an image without out-of-focus even in the infrared light region.

  Here, the operation of focusing on both the focus position 202 and the focus position 203 by controlling the aperture is shown. However, not only the aperture but also the focus position may be controlled to focus on both.

  Specifically, in the common use mode, the system controller 105 estimates the in-focus position 203 in the infrared light region from information such as the distance to the subject, the zoom magnification, and the wavelength of the target infrared light region. Next, the focus position 200 of the imaging apparatus is set to the focus position 205 which is estimated to be intermediate between the focus position 202 in the visible light region and the focus position 203 in the infrared light region shown in FIG. The imaging optical system 100 is controlled. In this way, by adjusting the focus position in consideration of the in-focus position 203 in the infrared light region and the in-focus position 202 in the visible light region, defocusing is reduced in both the visible light region and the infrared light region. Can do.

  Here, for the sake of explanation, the control of the aperture value and the focus position is individually described, but actually, the two are combined to perform control so that both the visible light region and the infrared light region are in focus.

  This combination may be set by the user.

  For example, since the difference in focus position between the visible light region and the infrared light region differs depending on the distance to the subject, if the difference is small, it may be possible to change only the aperture value or the focus position.

  In this embodiment, the aperture value and focus position of the image pickup apparatus are controlled in consideration of the wavelength characteristics of both the visible light region and the infrared light region, so that an image with no out-of-focus is obtained with one lens system. It is possible.

  With reference to FIG. 3, a case where a request for changing the aperture value setting is issued from the user in the common use mode will be described. Note that the processing of this flowchart is executed by the system controller 105.

  In this embodiment, the user can send an imaging parameter change request such as an aperture value to the system controller 105 using a UI or the like displayed on the display unit 104.

  When the process is started, in step S301, the system controller 105 accepts a request for changing the aperture value from the user. Then, the process proceeds to step S302.

  In step S302, the system controller 105 determines whether or not the requested aperture value is within an allowable range in the common use mode. Specifically, it is determined whether or not it is within the minimum aperture value specified in FIG. As a result of the determination, if it is within the range in the common use mode, the process proceeds to step S308. On the other hand, if it is out of range, the process proceeds to step S303.

  In step S303, the system controller 105 issues an aperture value change command within an allowable range in the common use mode. Specifically, the aperture value is determined within a range equal to or greater than the maximum aperture value specified in FIG. Then, the process proceeds to step S304.

  In step S304, the system controller 105 determines imaging parameters such as shutter speed and gain based on the aperture value determined in step S303. Here, it is desirable that the imaging parameters such as the shutter speed and the gain are determined so as to maintain an exposure condition that allows appropriate exposure to be performed. Then, the process proceeds to step S305.

  In step S305, the system controller 105 displays a dialog for obtaining setting permission indicating that a value different from the aperture value designated by the user is set on the display unit 104 or the like. More specifically, the system controller 105 displays an inquiry as to whether or not to switch to the preferential use mode on the display unit 104. Then, the process proceeds to step S306.

  In step S306, when the user gives an instruction to switch to the preferential use mode for the display, the system controller 105 advances the process to step S307. On the other hand, if there is no instruction to switch, the processing of this flowchart is terminated.

  In step S307, the system controller 105 switches from the common use mode to the priority use mode based on the instruction from the user in step S306. Then, the process proceeds to step S308.

  In step S308, the system controller 105 changes the imaging parameter to the aperture value instructed by the user in step S301. Then, the process proceeds to step S309.

  In step S309, the system controller 105 determines imaging parameters such as shutter speed and gain based on the aperture value set in step S308. Here, it is desirable that the imaging parameters such as the shutter speed and the gain are determined so as to maintain an exposure condition that allows appropriate exposure to be performed. Then, the process of this flowchart is complete | finished.

  Although only the change of the aperture value is described here, the focus position is also adjusted as necessary when the mode is switched.

  Next, the case where the common use mode is switched to the preferential use mode by the time schedule function will be described with reference to FIGS.

  FIG. 4 shows the operation for starting the common use mode.

  In step S401, the current mode is maintained until the start time of the set common use mode. More specifically, it is determined whether or not the current time becomes the set start time. If the current time matches the start time, the process proceeds to the next step S402.

  In step S402, the current use mode is switched from the preferential use mode to the common use mode.

  In step S403, the aperture value is changed so that focus is achieved in a plurality of wavelength regions.

  In step S404, the focus position is changed.

  In step S405, the imaging parameters such as shutter speed and gain are also changed according to the aperture value set in step S403.

  Next, FIG. 5 shows an operation for ending the common use mode.

  In step S501, the current mode is maintained until the set common use mode end time.

  In step S502, the current use mode is switched from the preferential use mode to the common use mode.

  In step S503, the aperture value is set without limitation for the preferred wavelength region.

  In step S504, the focus position is also adjusted for the priority wavelength region.

  In step S505, the imaging parameters such as shutter speed and gain are also changed according to the aperture value set in step S503.

  Here, for the sake of explanation, when the priority use mode and the common use mode are switched, the aperture value change, the focus position, and the imaging parameter change are described in this order. However, the present invention is not limited to this.

  Next, the case where the common mode and the priority use mode are switched according to the luminance value will be described with reference to FIGS. In the embodiment, it is assumed that the user uses the UI display of the display unit 104 and sets the luminance for mode switching. Note that the processing of this flowchart is executed by the system controller 105.

  FIG. 6 shows the operation when the luminance decreases and falls below a predetermined threshold. When the luminance of the subject is lowered, it is assumed that it is not necessary to maintain the common mode because the luminance cannot be secured when imaging with visible light is performed.

  In step S601, the current mode is maintained until the luminance of the imaged subject becomes equal to or lower than the mode switching setting value.

  In step S602, the mode is switched to a priority use mode in which priority is given to either one of the visible light region and the infrared light region. In the case of low luminance, it is preferable to prioritize the focus in the infrared light region.

  In step S603, since the mode is switched to the common mode, the aperture value is set without limitation.

  In step S604, the focus position is also changed by giving priority to a desired wavelength band.

  In step S605, imaging parameters such as shutter speed and gain are also changed.

  Next, FIG. 7 shows an operation when the luminance value rises above a predetermined threshold. It is assumed that the common mode is used when imaging with both visible light and infrared light is performed when the luminance of the subject increases.

  In step S701, the current mode is maintained until the luminance value becomes equal to or higher than the set value.

  In step S702, the current use mode is switched from the preferential use mode to the common use mode.

  In step S703, an aperture value is set using the table of FIG. 8 so that both the visible light region and the infrared light region are in focus.

  In step S704, the focus position is changed to be between the focus position in the visible light region and the focus position in the infrared light region.

  In step S705, imaging parameters such as shutter speed and gain are also changed.

  In the common use mode, the infrared device control unit 107 is controlled so that the subject image enters the image sensor 102 without passing through the infrared filter 101, and the infrared filter is removed 101. On the other hand, in the priority use mode, when giving priority to the visible light region, the subject image enters the image sensor 102 via the infrared filter 101, and when giving priority to the infrared light region, the infrared filter 101 is used. Insertion / extraction control is performed so as not to intervene. Further, the luminance value in this embodiment corresponds to luminance information used for mode switching.

  By performing the above operation, it is possible to set a suitable focus position by controlling the other focus position and the aperture diameter based on one focus position for a plurality of image sensors.

(Example 2)
FIG. 9 is a block diagram illustrating an example of a basic configuration of an imaging apparatus according to the second embodiment of the present invention. A subject image (not shown) is separated into a visible light component and an infrared light component by the prism 909 via the imaging optical system 900. More specifically, the prism 909 has a reflecting surface, and the reflecting surface is made of a material that reflects light having a wavelength of 650 nm or more. That is, the imaging apparatus of the present embodiment has a configuration in which the wavelength component of the subject image is separated using a prism as the reflection unit, so that the visible light component and the infrared light component can be separated at the same angle of view. is there. In the figure, the imaging optical system 900 is represented by a single lens, but is usually configured to include a plurality of lenses, a diaphragm, and the like. In this embodiment, the imaging optical system 900 and the prism 909 correspond to an optical unit for capturing a subject image.

  The separated visible light component is incident on a visible light imaging element 902 such as a CCD or CMOS sensor. In the present embodiment, the imaging unit including the visible light imaging element 902 corresponds to a visible light imaging unit that captures a visible light component included in the subject image.

  On the other hand, the infrared light component is incident on a near-infrared imaging device 908 manufactured from a material such as InGaAs (indium gallium arsenide). In this embodiment, the imaging unit including the near-infrared imaging element 908 corresponds to an infrared light imaging unit that captures an infrared light component included in the subject image.

  On the visible light image sensor 902 and the near infrared image sensor 908, a plurality of pixels that convert light into electric signals are arranged in a matrix. In each pixel, the imaged subject image is converted into an image signal and input to the image processing unit 903. The image input to the image processing unit 903 performs predetermined image processing such as gamma correction and color balance adjustment to generate an image file such as JPEG.

  The output image processed by the image processing unit 903 is displayed on the display unit 904 after predetermined display processing is performed. In addition, the user can operate and request the imaging apparatus by operating a UI displayed on the display unit 904. Note that. In order to operate the UI displayed on the display unit 904, an operation unit (not shown) may be used.

  Each of the above blocks is controlled by the system controller 905.

  The system controller 905 includes a CPU that controls the system. Specifically, the system controller 905 sets control instructions, parameters, and the like for each block. Further, the system controller 905 stores the result processed by each block in a memory (not shown), performs an operation, and outputs the result to each block. The memory is used as a storage area for various data such as a program storage area executed by the system controller 905, a work area during program execution, and unnecessary light generation conditions.

  Further, the system controller 905 acquires focus information from the image processing unit 103 in order to perform focus control performed by the imaging optical system control unit 906. Based on the acquired information, the system controller 905 sends a command to the imaging optical system control unit 906 in order to move the imaging optical system 900 to a focused position. In general, the focus information is information obtained by performing focus adjustment by a method such as contrast AF and phase difference AF, which is a function called autofocus (AF) for performing automatic focusing.

  First, the focus control in the common use mode in which setting is performed so that both the visible light imaging element 902 and the near-infrared imaging element 908 are focused will be described with reference to FIG.

  Reference numeral 1000 denotes a focus position of the imaging apparatus, and reference numeral 1001 denotes a depth of field of the imaging apparatus. Reference numeral 1002 denotes an in-focus position in the visible light image sensor, and reference numeral 1003 denotes an in-focus position in the near-infrared image sensor. In FIG. 10A, the imaging apparatus is set at a focus position 1002 in the visible light imaging element, the visible light imaging element 902 is in focus, and the image 1006 obtained from the visible light imaging element is out of focus. Absent. However, the near-infrared image sensor 908 is not in focus and the image 1007 obtained from the near-infrared image sensor is out of focus.

  In the common use mode, the imaging optical system 900 is controlled so that the depth of field 1001 covers the in-focus position 1003 in the near-infrared imaging device, and the aperture value is increased, and this is shown in FIG. The depth of field is increased to 1004. When changing the aperture value, the system controller 905 has a minimum aperture value setting table as shown in FIG. 16 for combinations of wavelength regions in which the imaging device to be focused in advance has sensitivity. The aperture value may be changed based on the setting table. Thereby, it is possible to acquire an image without out-of-focus even in the infrared light region.

  Next, a method for controlling the focus position of the imaging apparatus will be described.

  In FIG. 10A, the focus position 1000 of the image pickup apparatus is set to the focus position 1002 of the visible light image pickup element, and the near-infrared element is not in focus. In the common use mode, the system controller 905 estimates the focus position 1003 in the near-infrared imaging device from information such as the distance to the subject, the zoom magnification, and the wavelength characteristics of the target imaging device. Next, the focus position 1000 of the imaging apparatus is set to a focus position of 1005 shown in FIG. 10C, which is estimated to be intermediate between the focus position 1002 of the visible light image sensor and the focus position 1003 of the near-infrared image sensor. The imaging optical system 900 is controlled.

  In this way, the focus position is controlled in consideration of the in-focus position 1003 in the near-infrared imaging device and the in-focus position 1002 in the visible-light imaging device, and thus the out-of-focus image is in both the visible-light imaging device and the near-infrared imaging device. It is possible to obtain an image without any.

  Here, for the purpose of explanation, the control of the aperture value and the focus position is individually described. However, in actuality, control is performed so that both the visible light image sensor and the near-infrared image sensor are in focus by combining the two.

  This combination may be set by the user.

  For example, since the difference in focus position between the visible light image sensor and the near-infrared image sensor differs depending on the distance to the subject, only the aperture value or the focus position may be changed when the difference is small. Conceivable.

  In this embodiment, the aperture value and focus position of the image pickup apparatus are controlled in consideration of the wavelength characteristics of both the visible light image pickup device and the near-infrared image pickup device. It is possible to obtain no image.

  Next, a case where a request for changing the aperture value setting is issued from the user in the common use mode will be described with reference to FIG. Note that the processing of this flowchart is executed by the system controller 905.

  In this embodiment, the user can send a request for changing an imaging parameter such as an aperture value to the system controller 905 using a UI or the like displayed on the display unit 904.

  When the process is started, in step S1101, the system controller 905 receives a request for changing the aperture value from the user. Then, the process proceeds to step S1102.

  In step S1102, the system controller 905 determines whether or not the requested aperture value is within an allowable range in the common use mode. Specifically, it is determined whether or not it is within the minimum aperture value specified in FIG. If the result of this determination is that it is within the common use mode range, processing proceeds to step S1108. On the other hand, if it is out of range, the process proceeds to step S1103.

  In step S1103, the system controller 905 issues an aperture value change command within an allowable range in the common use mode. Specifically, the aperture value is determined within a range equal to or greater than the maximum aperture value specified in FIG. Then, the process proceeds to step S1104.

  In step S1104, the system controller 905 determines imaging parameters such as shutter speed and gain based on the aperture value determined in step S1103. Here, it is desirable that the imaging parameters such as the shutter speed and the gain are determined so as to maintain an exposure condition that allows appropriate exposure to be performed. Then, the process proceeds to step S1105.

  In step S1105, the system controller 905 displays a dialog for obtaining setting permission indicating that a value different from the aperture value designated by the user is set on the display unit 904 or the like. More specifically, the system controller 905 displays an inquiry as to whether or not to switch to the preferential use mode on the display unit 904. Then, the process proceeds to step S1106.

  In step S <b> 1106, the system controller 905 advances the process to step S <b> 1107 when the user has instructed the display to switch to the preferential use mode. On the other hand, if there is no instruction to switch, the processing of this flowchart is terminated.

  In step S1107, the system controller 905 switches from the common use mode to the priority use mode based on an instruction from the user in step S1106. Then, the process proceeds to step S1108.

  In step S1108, the system controller 905 changes the imaging parameter to the aperture value instructed by the user in step S1101. Then, the process proceeds to step S1109.

  In step S1109, the system controller 905 determines imaging parameters such as shutter speed and gain based on the aperture value set in step S1108. Here, it is desirable that the imaging parameters such as the shutter speed and the gain are determined so as to maintain an exposure condition that allows appropriate exposure to be performed. Then, the process of this flowchart is complete | finished.

  Although only the change of the aperture value is described here, the focus position is also adjusted as necessary when the mode is switched.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 100 Imaging optical system 101 Infrared filter 102 Imaging element 103 Image processing part 104 Display part 105 System controller 106 Imaging optical system control part 107 Infrared equipment control part

Claims (6)

An imaging apparatus having an optical unit for forming a subject image,
A focus adjusting means for adjusting a focus position of the optical unit;
A diaphragm adjusting means for adjusting a diaphragm diameter of the optical unit;
The optical unit includes a reflection unit that reflects either an infrared light component or a visible light component included in the subject image,
Control means for controlling the focus adjustment means and the aperture adjustment means;
And the infrared light imaging means for imaging the pre Kiaka outside light component through the diaphragm of the optical portion,
A visible light imaging means for imaging the pre-listen visible light component through the diaphragm of the optical portion,
With
The infrared light imaging means and the visible light imaging means can image in parallel,
The control unit controls the focus adjustment unit and the aperture adjustment unit based on the focus position of one of the infrared light imaging unit and the visible light imaging unit so that the other focus position is within the depth of field. An imaging apparatus characterized by:   The control means determines a priority use mode for determining one focus position of the infrared light imaging means and the visible light imaging means, and determines a common focus position between the infrared light imaging means and the visible light imaging means. The imaging apparatus according to claim 1, further comprising a common use mode.   The imaging apparatus according to claim 2, wherein the control unit switches between the preferential use mode and the common use mode based on current time or luminance information of the subject image. The imaging apparatus according to claim 1, wherein the reflection unit includes a prism having a reflection surface that reflects the infrared light component. 5. The control unit according to claim 1, wherein the control unit controls the focus adjustment unit and the aperture adjustment unit so that both the infrared light imaging unit and the visible light imaging unit are in focus. The imaging device described in 1. The control means controls only one of the focus adjustment means and the diaphragm adjustment means when a difference in focus position between the infrared light imaging means and the visible light imaging means is small. Item 6. The imaging device according to any one of Items 1 to 5.

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