JP6123137B2 - Camera device - Google Patents

Description

  The present invention relates to a camera device that images a spatial region on the opposite side of a transparent member through the transparent member.

  Conventionally, even when a desired imaging target is behind a transparent or translucent object as viewed from the image sensor side, the imaging target is clearly imaged without being affected by the reflection of external light on the object. There has been proposed a technique for obtaining such an image (see, for example, Patent Document 1). Patent Document 1 describes a technique for reducing reflected light generated in a transparent or translucent object by using a polarizing filter.

JP 2010-109562 A

  The configuration described in Patent Document 1 is a technique that mainly prevents external light from being reflected, and is transparent or translucent when the intensity of light irradiated to the imaging target is high, such as during the daytime. It can be considered that an imaging target located beyond the object can be imaged. However, when the amount of light irradiated to the imaging target is low, such as at night, it is difficult to image the imaging target behind the transparent or translucent object.

  An object of the present invention is to provide a camera device that can obtain an image of a required spatial region through a transparent member even when the ambient light is low, such as at night.

  The camera device according to the present invention includes an imaging unit that has a visual field in a specific direction and outputs an image, a first irradiation unit that irradiates light to a first spatial region that overlaps at least a part of the visual field, and the visual field When a transparent member is present in the field of view of the second irradiating unit that irradiates light to the second spatial region including other than the imaging unit, the spatial region that is opposite to the imaging unit with respect to the transparent member In order to extract the image of 1 from the image output by the imaging unit, the first image captured by the imaging unit using the light irradiated by the first irradiation unit and the second irradiation unit irradiated Using a second image picked up by the image pickup unit using light, a predetermined correction coefficient is applied to at least one of two pixel values at the same position for the first image and the second image. Multiplying to find the difference and generating a difference image with this difference as the pixel value A processing unit, and a control unit that controls operations of the imaging unit, the first irradiation unit, the second irradiation unit, and the image processing unit, and the correction coefficient is calculated from the first image It is set so that the component of the reflected light by a transparent member may be reduced.

  In this camera device, the first irradiation unit and the second irradiation unit are integrally coupled with the imaging unit, and the first irradiation unit emits light in the direction of the optical axis of the imaging unit. It is preferable that the second irradiating unit irradiates a spatial region excluding the field of view of the imaging unit as the second spatial region.

  In this camera device, the control unit may be configured such that a first period in which the first irradiation unit irradiates light and a second period in which the second irradiation unit irradiates light are different. , Controlling the first irradiating unit and the second irradiating unit, capturing the first image during the first period, and capturing the second image during the second period. It is preferable to control the imaging unit.

  In this camera device, it is further preferable that the control unit controls the first irradiation unit and the second irradiation unit so as to alternately generate the first period and the second period. .

  In this camera device, the imaging unit includes a first imaging unit that captures the first image during the first period, and a second imaging unit that captures the second image during the second period. The control unit causes the second imaging unit to output the second image during the first period, and causes the first imaging unit to output the first image during the second period. It is further preferable to output an image.

  In this camera device, it is preferable that the second irradiation unit includes a plurality of light emitting units having different light emission directions.

  In this camera device, the first irradiation unit includes a light emitting unit that outputs light, and a first polarizing filter that passes linearly polarized light having a specific vibration surface out of the light output from the light emitting unit, It is preferable that the imaging unit includes a second polarizing filter that allows light having a vibration surface in a direction intersecting with a vibration surface of linearly polarized light passing through the first polarizing filter to pass.

  In this camera device, the light emitting unit may further include a light source and a reflecting member that diffusely reflects the light emitted from the light source and reflected by the first polarizing filter in the direction of the first spatial region. preferable.

  In this camera device, the control unit includes the first irradiation unit and the second irradiation unit so as to provide a non-irradiation period in which neither the first irradiation unit nor the second irradiation unit emits light. And controlling the imaging unit so that imaging is performed in the non-irradiation period in addition to the first period and the second period, and the image processing unit is configured to control the imaging unit in the first period. From the image captured by the image capturing unit and the image captured by the image capturing unit during the non-irradiation period, a difference between pixel values of pixels at the same position is obtained, and an image using the difference as a pixel value is used for the first image. From the image captured by the imaging unit during the second period and the image captured by the imaging unit during the non-irradiation period, a difference between the pixel values of the pixels at the same position is obtained, and an image using the difference as the pixel value is determined as the pixel value. It is preferably used for the second image.

  In this camera apparatus, it is preferable that the imaging unit includes an optical filter that selectively transmits a wavelength of light emitted by the first irradiation unit and the second irradiation unit.

  In this camera device, the image processing unit includes a table in which the correction coefficient to be multiplied by a pixel value of at least one pixel of the first image and the second image is set according to the position of the pixel. It is preferable.

  In this camera device, the image processing unit generates the difference image by changing the correction coefficient, and sets the correction coefficient when an evaluation value for the number of edges obtained from the difference image satisfies a predetermined condition. It is preferable to adopt.

  In this camera device, the image processing unit generates the difference image by changing the correction coefficient, and adopts the correction coefficient when an evaluation value for a pixel value obtained from the difference image satisfies a predetermined condition. It is preferable to do.

  In this camera device, it is preferable that the control unit generates the first image and the second image in units of one frame of the imaging unit.

  In this camera device, it is preferable that the control unit obtains the second image when a pixel value of the first image exceeds a predetermined reference value.

  In this camera device, it is preferable that the control unit obtains the second image at regular time intervals.

  In this camera device, the first irradiation unit and the second irradiation unit have different wavelengths of light to be irradiated, and the imaging unit determines the wavelength of light irradiated from the first irradiation unit. A first imaging unit including a first optical filter that selectively transmits, and a second imaging unit including a second optical filter that selectively transmits the wavelength of light emitted from the second irradiation unit. Preferably, the first image is an image captured by the first imaging unit, and the second image is an image captured by the second imaging unit.

  In this camera device, the image processing unit detects an intruder into the first space region by using a plurality of the difference images obtained at different times and detecting a change in the difference image. It is preferable.

  According to the configuration of the present invention, the first irradiation unit that irradiates light to a spatial region that overlaps at least part of the visual field of the imaging unit, and the second irradiation that irradiates light to a spatial region that includes other than the visual field of the imaging unit. A transparent member using an image captured during a period in which light is emitted from the first irradiation unit and an image captured in a period during which light is emitted from the second irradiation unit. Therefore, even when the ambient light is low, such as at night, an image of a required spatial region can be obtained through the transparent member.

1 is a block diagram illustrating a first embodiment. FIG. 3 is a plan view illustrating a usage example of the first embodiment. FIG. 6 is a diagram illustrating an operation example of the first embodiment. 1 is a schematic configuration diagram illustrating a first embodiment. FIG. 2 is a schematic configuration diagram illustrating a configuration example of a main part of the first embodiment. 3 is a diagram illustrating an example of an image in Embodiment 1. FIG. FIG. 2 is a schematic diagram illustrating a configuration example of a main part of the first embodiment. FIG. 2 is a schematic diagram illustrating a configuration example of a main part of the first embodiment. FIG. 3 is a block diagram illustrating a configuration example of a main part of the first embodiment. FIG. 6 is a block diagram illustrating a second embodiment. 10 is a diagram illustrating an operation example of Embodiment 2. FIG. FIG. 6 is a block diagram illustrating a third embodiment.

(Embodiment 1)
As shown in FIG. 1, the camera device 1 described below includes an imaging unit 10, a first irradiation unit 11, a second irradiation unit 12, an image processing unit 13, and a control unit 14. The imaging unit 10 has a visual field 20 (see FIG. 2) in a specific direction and outputs an image. The 1st irradiation part 11 irradiates light to the 1st space area | region 21 (refer FIG. 2) which overlaps at least one part of the visual field 20. FIG. The 2nd irradiation part 12 irradiates light to the 2nd space area | region 22 (refer FIG. 2) other than the visual field 20. FIG.

  When the transparent member 23 is present in the visual field 20 of the imaging unit 10, the image processing unit 13 extracts an image of a spatial region on the opposite side of the imaging unit 10 with respect to the transparent member 23 from the image output by the imaging unit 10. To do. In order to extract the image of the spatial region 211, the first image 51 (see FIG. 6) captured by the imaging unit 10 using the light irradiated by the first irradiation unit 11 and the second irradiation unit 12 emit the light. The second image 52 (see FIG. 6) captured by the imaging unit 10 using the light that has been used is used. The image processing unit 13 obtains a difference between the first image 51 and the second image 52 by multiplying at least one of the pixel values of two pixels at the same position by a predetermined correction coefficient, and this difference is calculated as the pixel value. The difference image 53 (see FIG. 6) to be generated is generated. The control unit 14 controls operations of the imaging unit 10, the first irradiation unit 11, the second irradiation unit 12, and the image processing unit 13. The correction coefficient is set so as to reduce the component of light reflected by the transparent member 23 from the first image 51.

  Further, it is desirable that the first irradiation unit 11 and the second irradiation unit 12 are integrally coupled to the imaging unit 10. In this case, the first irradiating unit 11 irradiates light in the direction of the optical axis of the imaging unit 10, and the second irradiating unit 12 defines the spatial region excluding the visual field of the imaging unit 10 as the second spatial region 22. It is desirable to do.

  Furthermore, the control unit 14 includes a first period 41 (see FIG. 3) in which the first irradiation unit 11 emits light, and a second period 42 (see FIG. 3) in which the second irradiation unit 12 emits light. The first irradiating unit 11 and the second irradiating unit 12 are controlled so as to be different from each other. In addition, it is desirable that the control unit 14 controls the imaging unit 10 so that the first image 51 is captured in the first period 41 and the second image 52 is captured in the second period 42.

  In the present embodiment, the control unit 14 controls the first irradiation unit 11 and the second irradiation unit 12 so as to alternately generate the first period 41 and the second period 42.

  As shown in FIG. 5, the second irradiation unit 12 preferably includes a plurality of light emitting units 112 having different light emission directions.

  In addition, as shown in FIG. 7, the first irradiating unit 11 includes a light emitting unit 112 that outputs light, and a first polarized light that passes linearly polarized light having a specific vibration surface out of the light output from the light emitting unit 112. It is preferable to include a filter 113. In this case, the imaging unit 10 preferably includes a second polarizing filter 103 that allows light having a vibration surface in a direction intersecting with the vibration surface of linearly polarized light passing through the first polarizing filter 113 to pass therethrough. Further, the light emitting unit 112 may include a light source 111 and a reflection member 114 that diffuses and reflects light emitted from the light source 111 and reflected by the first polarizing filter 113 in the direction of the first spatial region 21. .

  The imaging unit 10 preferably includes an optical filter (optical element 102) that selectively transmits the wavelength of light emitted by the first irradiation unit 11 and the second irradiation unit 12.

  Further, the image processing unit 13 sets a table 1321 (see FIG. 9) in which a correction coefficient to be multiplied by the pixel value of at least one pixel of the first image 51 and the second image 52 is set according to the pixel position. It is desirable to provide. Further, the image processing unit 13 generates the difference image 53 with different correction coefficients, and adopts the correction coefficient when the evaluation value for the number of edges obtained from the difference image 53 satisfies a predetermined condition. desirable. Alternatively, the image processing unit 13 may generate the difference image 53 with different correction coefficients, and adopt the correction coefficient when the evaluation value for the pixel value obtained from the difference image 53 satisfies a predetermined condition. desirable.

  The control unit 14 desirably generates the first image 51 and the second image 52 in units of one frame of the imaging unit 10. Further, the control unit 14 acquires the second image 52 when the pixel value of the first image 51 exceeds a predetermined reference value, or acquires the second image 52 at a constant time interval. You may make it acquire.

  Hereinafter, the configuration of the present embodiment will be described in more detail. Here, as shown in FIG. 2, it is assumed that the camera device 1 is arranged near the window 32 in the room 31 of the building 30 and the outdoor device 32 is taken as an object to be monitored by the camera device 1. The camera device 1 is arranged away from the window 32 by several cm to several tens of cm.

  A window glass 231, which is a transparent member 23, is disposed in the window 32, and the camera device 1 photographs the space region 211 in the outdoor 32 through the window glass 231. The spatial region 211 is included in the range of the visual field 20 of the imaging unit 10 provided in the camera device 1 and means a spatial region that is the outdoor 32 with respect to the window glass 231. The imaging unit 10 is configured to output a grayscale image or a color image. Hereinafter, a case where the imaging unit 10 outputs a grayscale image will be described as an example. As shown in FIG. 4, the imaging unit 10 includes an imaging element 101 such as a CCD image sensor or a CMOS image sensor, and an optical element including a light receiving lens (not shown) that controls light incident on the imaging element 101. 102. A configuration example of the optical element 102 will be described later.

  As shown in FIG. 2, the camera device 1 includes a first irradiation unit 11 and a second irradiation unit 12 in addition to the imaging unit 10. The first spatial region 21 to which the first irradiation unit 11 emits light substantially coincides with the visual field 20 of the imaging unit 10. It is not essential that the first spatial region 21 coincides with the visual field 20, and at least a part of the first spatial region 21 may overlap the visual field 20 and include the required spatial region 211 of the outdoor 32 to be monitored. . In short, the 1st irradiation part 11 should just be comprised so that light may be irradiated to the space area | region 211 which is the outdoor 32 with respect to the window glass 231, and is going to monitor with the camera apparatus 1. FIG. Since the light emitted from the first irradiation unit 11 needs to pass through the window glass 231 and reach the space region 211 in the outdoor 32, the light output of the first irradiation unit 11 may be relatively large. desirable.

  On the other hand, the second spatial region 22 to which the second irradiation unit 12 emits light includes a spatial region that is not the field of view 20 of the imaging unit 10. The second spatial region 22 is desirably a spatial region excluding the visual field 20 of the imaging unit 10, but it is allowed to include the visual field 20 of the imaging unit 10 as a part. In addition, the second space region 22 is the room 31 and is desirably a space region having as wide an angular range as possible.

  The first irradiation unit 11 and the second irradiation unit 12 have, for example, the configuration shown in FIG. 5 in order to satisfy the functions described above. The configuration example shown in the figure is a configuration in which light emitting units 112 and 122 including a light source 111 such as a light emitting diode are attached to a base 110, and includes a first irradiation unit 11 and a second irradiation unit 12 integrally. The base 110 is formed in a curved surface having a front surface 1101 (upper surface in FIG. 5) as a flat surface and a back surface 1102 protruding outward. In addition, a plurality of light emitting portions 112 and 122 are arranged at appropriate intervals on the front surface 1101 and the back surface 1102, respectively. Desirably, the surface of the base 110 is given diffuse reflectivity by application of a white paint or the like.

  In the configuration example shown in FIG. 5, the individual light emitting units 112 constituting the first irradiation unit 11 and the individual light emitting units 122 constituting the second irradiation unit 12 are both in the direction of the center line of the light irradiation range. Are arranged so as to substantially coincide with the normal direction of the outer peripheral surface of the base 110. The direction of the center line of the light irradiation range from the light emitting units 112 and 122 substantially coincides with the direction of the maximum output in the distribution of the light output from the light emitting units 112 and 122.

  With the above-described configuration, the light emitting units 112 constituting the first irradiation unit 11 are arranged in substantially the same direction, and the irradiation ranges of the respective light emitting units 112 substantially overlap. On the other hand, the plurality of light emitting units 122 constituting the second irradiation unit 12 are arranged such that the center line of the light irradiation range is radial. Therefore, the second irradiation unit 12 can irradiate light over a wide angle range. In addition, since the light emitting units 112 and 122 are attached to the base 110 having the shape shown in FIG. 5, the first spatial region 21 where the first irradiation unit 11 irradiates light and the second irradiation unit 12 include It becomes an independent range without overlapping with the second spatial region 22 that irradiates light.

  As shown in FIG. 1, the control unit 14 controls the timing of imaging by the imaging unit 10, the timing of irradiating light from the first irradiation unit 11, and the timing of irradiating light from the second irradiation unit 12. To do. For example, as illustrated in FIG. 3A, the control unit 14 alternately emits light from the first irradiation unit 11 and the second irradiation unit 12. Hereinafter, a period in which light is emitted from the first irradiation unit 11 is referred to as a first period 41, and a period in which light is emitted from the second irradiation unit 12 is referred to as a second period 42.

  In addition, as illustrated in FIGS. 3B and 3C, the control unit 14 causes the imaging unit 10 to perform imaging in the first period 41 and the second period 42, respectively. Therefore, the imaging unit 10 captures an image using the light irradiated by the first irradiation unit 11 during the first period 41 and uses the light irradiated by the second irradiation unit 12 during the second period 42. Take an image. Hereinafter, an image captured by the imaging unit 10 in the first period 41 is referred to as a first image 51 (see FIG. 6), and an image captured by the imaging unit 10 in the second period 42 is a second image 52 ( This is referred to as FIG.

  The minimum period between the first period 41 and the second period 42 is a period in which the imaging unit 10 captures an image of one frame, and the first image 51 and the second image 52 are captured for each frame. One can be. In this case, the time during which the first irradiation unit 11 and the second irradiation unit 12 irradiate light is also a period of one frame. In other words, each time the imaging unit 10 captures an image of one frame, the control unit 14 has a state in which light is emitted from the first irradiation unit 11 and a state in which light is emitted from the second irradiation unit 12. Make a choice. Note that each of the first period 41 and the second period 42 may extend over a plurality of frames.

  Since the imaging unit 10 captures the space area 211 of the outdoor 32 through the window glass 231, the information on the space area 211 of the outdoor 32 and the window glass 231 are reflected in the first image 51 and the second image 52, respectively. Information on the room 31 is included. On the other hand, the present embodiment aims to reduce or remove information on the room 31 reflected on the window glass 231 and extract information on the space region 211 of the outdoor 32.

  Since the first image 51 is an image captured by the imaging unit 10 using the light irradiated by the first irradiation unit 11, the light from the spatial region 211 in the outdoor 32 is received as shown in FIG. A relatively large amount of light from the room 31 reflected by the window glass 231 is also included. On the other hand, the second image 52 is an image picked up by the image pickup unit 10 using the light emitted by the second irradiation unit 12, and therefore, as shown in FIG. Although the amount of light is small, a relatively large amount of light from the room 31 reflected by the window glass 231 is included.

  Now, of the pixel values (light and shade values) of the first image 51, the component corresponding to the spatial region 211 is J11, and the component corresponding to the reflected light from the window glass 231 is J12. Of the pixel values (light and shade values) of the second image 52, the component corresponding to the spatial region 211 is J21, and the component corresponding to the reflected light from the window glass 231 is J22. Note that, in the first image 51 and the second image 52, external light and illumination that cause noise are ignored here. Light that becomes noise is reduced by using an optical filter described later and also by a technique described later.

  If the above-mentioned codes are used, it is considered that J11> J21 and J12 <J22 are established. In short, it is considered that the light from the space region 211 is more in the first image 51 and the light from the room 31 is more in the second image 52. Here, if an appropriate correction coefficient ω can be determined so that the relationship of J12 = ω · J22 is established, J11 + J12−ω (J21 + J22) = J11−ω · J21 and light from the room 31 is removed. it can.

  That is, a value obtained by multiplying the pixel value of each pixel of the second image 52 by an appropriate correction coefficient ω is subtracted from the pixel value of the pixel of the first image 51 at the same position as the second image 52. By doing so, the information of the room 31 reflected on the window glass 231 can be reduced or removed. Therefore, if an appropriate correction coefficient ω is set, the difference image 53 in which the component of the reflected light from the window glass 231 is substantially removed from the first image 51 and the second image 52 as shown in FIG. Is obtained.

  If the correction coefficient ω is appropriately set so that ω · J12 = J22 is established, ω (J11 + J12) − (J21 + J22) = ω · J11−J21, and this processing also reflects on the window glass 231. It is possible to substantially remove the light component. In this way, either the pixel value of the first image 51 or the pixel value of the second image 52 may be multiplied by the correction coefficient ω, or both may be multiplied by the correction coefficient, Hereinafter, a case where the pixel value of the second image 52 is multiplied by the correction coefficient ω will be described as an example. A technique for determining the correction coefficient ω will be described later.

  The image processing unit 13 performs the process of removing the reflected light from the window glass 231 using the first image 51 and the second image 52. The image processing unit 13 is a computer that realizes functions described below according to a program, and includes a processor that processes the program and an interface device as main hardware elements. This type of computer may have any configuration such as a microcomputer including a memory integrally with a processor, or a configuration including a memory separately from the processor.

  The program is installed in the image processing unit 13 by storing in advance in a ROM (Read Only Memory), writing from a program support apparatus, or downloading through an electric communication line such as the Internet. The program may be provided by a computer-readable recording medium.

  As illustrated in FIG. 1, the image processing unit 13 includes a storage unit 131 that stores a grayscale image captured by the imaging unit 10. The storage unit 131 images the first image 51 captured using the light of the first irradiation unit 11 during the first period 41 and the light of the second irradiation unit 12 during the second period 42. The second image 52 is stored. The image processing unit 13 uses a coefficient determination unit 132 that determines a correction coefficient by which the pixel value (shading value) of the second image 52 stored in the storage unit 131 is multiplied, and a correction coefficient that is determined by the coefficient determination unit 132. And a calculation unit 133 that performs the above-described calculation (weighted subtraction).

  The computing unit 133 obtains a value obtained by multiplying the pixel value of each pixel of the second image 52 by the correction coefficient. Since the pixels of the first image 51 and the pixels of the second image 52 have a one-to-one correspondence, the arithmetic unit 133 performs the operation for every two corresponding pixels (that is, pixels at the same position). Then, a value obtained by multiplying the pixel value of the second image 52 by the correction coefficient is subtracted from the pixel value of the pixel of the first image 51. Then, the calculation unit 133 generates a difference image 53 using the subtraction result as a new pixel value of the corresponding pixel. That is, the calculation unit 133 generates a difference image 53 illustrated in FIG. 6C from the first image 51 illustrated in FIG. 6A and the second image 52 illustrated in FIG.

  In the difference image formed as described above, the component of the reflected light from the window glass 231 is reduced, and it becomes easy to extract the information of the spatial region 211 of the outdoor 32 from the image. Therefore, it is possible to extract the feature amount on the image in the space region 211 based on the difference image obtained by the calculation unit 133, and for example, it is possible to be wary of an intruder. Moreover, since light is irradiated from the 1st irradiation part 11 with respect to the space area | region 211, even when there is little ambient light like nighttime, it becomes possible to monitor the space area | region 211. FIG.

  In the operation example described above, the control unit 14 irradiates light alternately from the first irradiation unit 11 and the second irradiation unit 12, but the change in the second image 52 is less with time. In this case, it is not necessary to irradiate light alternately from the first irradiation unit 11 and the second irradiation unit 12. For example, the control unit 14 may repeat the operation of irradiating the light from the second irradiation unit 12 once and then irradiating the light from the first irradiation unit 11 a plurality of times.

  For this reason, the second period 42 can be provided only when a change occurs in the second image 52 in addition to being provided at regular time intervals. In the latter case, the second image 52 cannot be used to provide the second period. Therefore, the control unit 14 monitors the change in the pixel value of the first image 51, and when the difference (absolute value) of the representative value of the pixel value in the first image 51 exceeds a predetermined reference value, The image 52 is updated. As the representative value of the pixel value, an average value, a mode value, a median value, a range (difference between the maximum value and the minimum value), or the like is used.

  That is, since the first image 51 includes light reflected by the window glass 231, the first image 51 also changes when the second image 52 changes. Utilizing this fact, when a relatively large change occurs in the pixel value of the first image 51, the component of the reflected light from the difference image 53 and the window glass 231 is updated by updating the second image 52. Can be reduced.

  Although it is not the main point to limit, the light irradiated from the 1st irradiation part 11 and the 2nd irradiation part 12 is an infrared region in order to make it difficult for the person who exists in the space area 211 to notice light irradiation. Is desirable. When the camera device 1 is incorporated in a lamp, an object, or the like, the light emitted from the first irradiation unit 11 and the second irradiation unit 12 may be a visible light region.

  The light output from the first irradiation unit 11 and the second irradiation unit 12 is substantially a single wavelength regardless of whether it is an infrared region, a visible light region, or an ultraviolet region. It is desirable. That is, it is desirable that the first irradiating unit 11 and the second irradiating unit 12 irradiate light having a narrow half-value width and a small wavelength region.

  Thus, when the 1st irradiation part 11 and the 2nd irradiation part 12 irradiate substantially single wavelength light, as the optical element 102 (refer FIG. 4) of the imaging part 10, selective permeability with respect to a wavelength is provided. It is desirable to use an optical filter provided. That is, the imaging unit 10 can mainly receive light emitted from the first irradiation unit 11 and the second irradiation unit 12, and the interior of the room 31 with respect to the first image 51 and the second image 52 can be received. The influence of illumination light and natural light outside the room 32 is reduced. In short, it is possible to generate the first image 51 mainly using light from the first irradiation unit 11 and generate the second image 52 mainly using light from the second irradiation unit 12. It becomes possible to suppress noise caused by illumination light or natural light.

  By the way, since the 1st irradiation part 11 irradiates light in the direction of the optical axis of the imaging part 10, the light irradiated from the 1st irradiation part 11 reflects regularly with the window glass 231 which is the transparent member 23. May enter the imaging unit 10. Of the light irradiated from the first irradiation unit 11, the light reflected by the window glass 231, re-reflected by the window glass 231, and incident on the imaging unit 10, as described above, causes the second image 52 to be reflected. It can be reduced or eliminated by use. However, the light that is emitted from the first irradiation unit 11 and is regularly reflected by the window glass 231 and incident on the imaging unit 10 is not included in the second image 52, and is therefore reduced using the second image 52. I can't.

  In order to reduce the influence of the light regularly reflected by the window glass 231, as shown in FIG. 7, the first irradiation unit 11 includes a first polarizing filter 113, and the imaging unit 10 includes the optical element 102 (see FIG. 4). ) Is preferably provided with the second polarizing filter 103.

  The first polarizing filter 113 has a function of passing linearly polarized light having a specific vibration surface out of the light output from the light emitting unit 112 provided in the first irradiation unit 11. The second polarizing filter 103 has a function of allowing linearly polarized light to pass therethrough so that light having an oscillating plane intersecting the linearly oscillating plane passing through the first polarizing filter 113 is allowed to pass. Be placed.

  The vibration planes of the first polarizing filter 113 and the second polarizing filter 103 are generally required to be orthogonal, but are not necessarily orthogonal. That is, among the light irradiated from the first irradiation unit 11, the light that is regularly reflected by the window glass 231 and incident on the imaging element 101 of the imaging unit 10 may be reduced. By adopting this configuration, it is possible to alleviate a phenomenon in which the output of the image sensor 101 is saturated when light regularly reflected by the window glass 231 enters the image sensor 101.

  When the first irradiation unit 11 includes the first polarizing filter 113 as in the configuration example illustrated in FIG. 7, in order to increase the light flux from the light emitting unit 112 to the polarizing filter 113, the reflection is performed as illustrated in FIG. 8. A member 114 may be provided. In other words, the light emitting unit 112 includes the light source 111 and the reflecting member 114, and the reflecting member 114 surrounds the area around the light source 111 other than the range in which the first spatial region 21 is irradiated with light. The reflecting member 114 has a bowl-shaped reflecting surface with one surface open, and diffuse reflecting property is imparted to the reflecting surface by a white paint or the like.

  With this configuration, the light emitted from the light source 111 and not directed to the first polarizing filter 113 and the light that has been irradiated to the first polarizing filter 113 but did not pass through the first polarizing filter 113 are reflected members. 114 is reflected toward the first polarizing filter 113. Therefore, among the light emitted from the light source 111, the light passing through the first polarizing filter 113 is increased as compared with the case where the reflecting member 114 is not provided, and as a result, the loss of light by the first polarizing filter 113. Is suppressed. If the intensity of the light emitted through the first polarizing filter 113 is the same as that of the configuration in which the reflecting member 114 is not provided, the intensity of the light emitted from the light source 111 can be reduced. That is, the number of light sources 111 or the power supplied to the light sources 111 can be reduced.

  As described above, it is important to determine the correction coefficient when obtaining the difference image 53 from the first image 51 and the second image 52. In the present embodiment, the coefficient determination unit 132 determines the correction coefficient. As shown in FIG. 9, the coefficient determination unit 132 preferably includes a table 1321 that stores correction coefficients.

  Here, it is conceivable that the calculation unit 133 uniformly multiplies the pixel value (gray value) for each pixel in the second image 52 by the same correction coefficient. However, actually, the intensity of the light reflected by the window glass 231 and incident on the imaging unit 10 varies depending on the part of the first image 51, and when the same correction coefficient is uniformly applied to the entire second image 52, There is a possibility that reflected light from the window glass 231 cannot be reduced from the first image 51. This is because the intensity of the light reflected by the window glass 231 and incident on the imaging unit 10 depends on the distance to the object existing in the room 31.

  Therefore, it is desirable that the correction coefficient stored in the table 1321 is set according to the area of the second image 52. Therefore, the coefficient determination unit 132 includes a region division unit 1322 that performs region division based on information (pixel value distribution) obtained from the second image 52. The area dividing unit 1322 determines a correction coefficient for each divided area, and stores the determined correction coefficient in the table 1321. In principle, the area dividing unit 1322 divides the second image 52 into a plurality of areas, but handles the entire second image 52 as one area when it is not necessary to divide the area.

  In order to determine a correction coefficient for each area of the second image 52, the area dividing unit 1322 divides the area based on information obtained from the second image 52. Even if only the information obtained from the second image 52 is used, the component reflected by the window glass 231 in the difference image 53 can be attenuated. However, the correction coefficient is evaluated based on the difference image 53, and the correction coefficient If reflected in, the component reflected by the window glass 231 can be further reduced.

  In order to evaluate the correction coefficient, the difference image 53 is obtained in a period in which the state of the space 32 in the outdoor 32 does not change, and the number of edges or the pixel value included in the difference image 53 is evaluated. The edge can be easily obtained by applying an edge enhancement filter such as a sobel filter to the pixel value. The detection of an edge indicates that the variation in pixel values is relatively large. On the other hand, in the difference image 53, if the component of reflection from the window glass 231 is reduced, the number of edges is considered to be minimal.

  Utilizing this fact, the area dividing unit 1322 changes the correction coefficient for each appropriately divided area, and adopts the correction coefficient when the number of edges is minimized (or less than a threshold value). Furthermore, if the difference between the correction coefficients of adjacent areas is within a predetermined range, the area dividing unit 1322 integrates the areas and applies the same correction coefficient. By storing the correction coefficients for each region integrated in this way in the table 1321, it is possible to obtain the difference image 53 in which the light reflected by the window glass 231 is reduced.

  The same applies to the case where the pixel value is evaluated instead of evaluating the edge. If the reflection from the window glass 231 can be removed, the pixel value becomes minimum (the pixel value is determined to increase as the brightness increases). Therefore, the area dividing unit 1322 may change the correction coefficient for each area and use the correction coefficient when the sum of the pixel values obtained for each area becomes minimum (or less than a threshold value).

  In the example described above, when the correction coefficient is determined using the difference image 53, it is used on the condition that the number of edges or the pixel value extracted from the difference image 53 is minimal or less than a threshold value. The evaluation value may be used. In short, the area dividing unit 1322 obtains the differential image 53 with the correction coefficient changed, and adopts the correction coefficient at that time when the evaluation value for the number of edges or the pixel value satisfies a predetermined condition.

(Embodiment 2)
In the first embodiment, the first image 51 and the second image 52 are captured by one imaging unit 10. In contrast, the present embodiment employs a configuration in which a first imaging unit 10A that captures the first image 51 and a second imaging unit 10B that captures the second image 52 are provided. .

  That is, in the camera device 1 of the present embodiment, as illustrated in FIGS. 10 and 11, the imaging unit 10 includes the first imaging unit 10 </ b> A that captures the first image 51 in the first period 41, A second imaging unit 10B that captures the second image 52 in the period 42 is individually provided. In addition, the control unit 14 outputs the second image 52 from the second imaging unit 10B in the first period 41, and outputs the first image 51 from the first imaging unit 10A in the second period 42. .

  Hereinafter, this embodiment will be described in more detail. As shown in FIG. 10, the imaging unit 10 includes a first imaging unit 10A and a second imaging unit 10B each including an imaging element 101 (see FIG. 4). Although it is assumed that the optical element 102 (see FIG. 4) includes the first imaging unit 10A and the second imaging unit 10B separately, the first imaging unit 10A and the second imaging unit 10B It can also be configured to be shared. A first image 51 is output from the first imaging unit 10A, and a second image 52 is output from the second imaging unit 10B.

  As shown in FIG. 11A, the control unit 14 includes a first period 41 in which light is emitted from the first irradiation unit 11 and a second period 42 in which light is emitted from the second irradiation unit 12. The period for irradiating light from the first irradiation unit 11 and the second irradiation unit 12 is controlled so as not to overlap each other. In addition, as shown in FIG. 11B, the first imaging unit 10A takes an image in the first period 41, and as shown in FIG. 11C, the second imaging unit 10B takes an image in the second period 42. In this way, the control unit 14 controls.

  In the first embodiment, the image captured by the imaging unit 10 in the first period 41 is output as the first image 51 in the first period 41, and the image captured by the imaging unit 10 in the second period 42 is the second period. The image 52 is output in the second period 42. On the other hand, in the present embodiment, the image captured by the first imaging unit 10A in the first period 41 is output as the first image 51 in the second period 42, and the second imaging unit 10B An image captured in the second period 42 is output as a second image in the first period 41.

  Here, in the present embodiment, it is assumed that the exposure times of the first imaging unit 10A and the second imaging unit 10B are set equal to the exposure time of the imaging unit 10 in the first embodiment. In this case, in the configuration of the present embodiment, the first period 41 and the second period 42 output images from the first imaging unit 10A and the second imaging unit 10B in comparison with the configuration of the first embodiment. It becomes possible to shorten the time.

  By the way, the first imaging unit 10A and the second imaging unit 10B include the imaging element 101 (see FIG. 4), and outputting images from the first imaging unit 10A and the second imaging unit 10B is not possible. The charge is read from the image sensor 101. The time for reading out charges from the image sensor 101 is relatively long because it involves the transfer of charges. Accordingly, by outputting an image from the first imaging unit 10A in the second period 42 and outputting an image from the second imaging unit 10B in the first period 41, the first period 41 and the second period 42 can be shortened relatively large.

  As described above, since the first period 41 and the second period 42 are shortened, the time interval for obtaining the first image 51 can be shortened, and as a result, the time change in the spatial region 211 is reflected. It becomes easy to do. In other words, the frame rate for outputting the above-described difference image can be increased. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3)
The timing at which the first image 51 is captured is different from the timing at which the second image 52 is captured in the first embodiment and the second embodiment, but in the present embodiment, the first image 51 and the second image are different. The structure which images 52 simultaneously is illustrated.

  In the present embodiment, the first irradiation unit 11 and the second irradiation unit 12 have different wavelengths of light to be irradiated. Further, as shown in FIG. 12, the imaging unit 10 includes a first imaging unit 10A and a second imaging unit 10B. The first imaging unit 10A includes a first optical filter 104A that selectively transmits the wavelength of light emitted from the first irradiation unit 11. The second imaging unit 10B includes a second optical filter 104B that selectively transmits the wavelength of light emitted from the second irradiation unit 12. The first image 51 uses an image captured by the first imaging unit 10A, and the second image 52 uses an image captured by the second imaging unit 10B.

  That is, the optical elements 102 of the first imaging unit 10A and the second imaging unit 10B are the first optical filter 104A and the second optical filter 104B having wavelength selectivity. The first optical filter 104A and the second optical filter 104B have different wavelengths for transmission. The first irradiation unit 11 emits light having a wavelength that passes through the first optical filter 104A, and the second irradiation unit 12 emits light having a wavelength that passes through the second optical filter 104B. For example, as the first optical filter 104A, one that transmits 850 nm light is used when the first irradiation unit 11 irradiates light of 850 nm. As the second optical filter 104B, a filter that transmits 950 nm light is used when the second irradiation unit 12 emits light of 950 nm.

  Even if the 1st irradiation part 11 and the 2nd irradiation part 12 irradiate light simultaneously by this structure, each light is isolate | separated into 10 A of 1st imaging parts, and the 2nd imaging part 10B. Received light. That is, the period in which the first irradiation unit 11 irradiates the first spatial region 21 with the period in which the second irradiation unit 12 irradiates the second spatial region 22 can be overlapped.

  By adopting the configuration of the present embodiment, the first image 51 and the second image 52 can be obtained at the same time. Therefore, even when there is an object moving in the second space region 22, the first image 51 and the second image 52 are obtained simultaneously. There is no positional shift between the image 51 and the second image 52. That is, even when an object moving in the second space region 22 exists, the difference image 53 in which the reflection component from the window glass 231 is reduced or removed is obtained. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 4)
In each embodiment described above, the imaging unit 10 performs imaging in the first period 41 in which the first irradiation unit 11 irradiates light and the second period 42 in which the second irradiation unit 12 irradiates light. Is going. In other words, either the first irradiation unit 11 or the second irradiation unit 12 irradiates light during the period in which the imaging unit 10 captures an image.

  In the present embodiment, the control unit 14 provides the first irradiation unit 11 and the second irradiation unit 12 so as to provide a non-irradiation period in which neither the first irradiation unit 11 nor the second irradiation unit 12 emits light. To control. In addition to the first period 41 and the second period 42, the control unit 14 controls the imaging unit 10 so as to capture an image during the non-irradiation period. The image processing unit 13 obtains the difference between the pixel values of the pixels at the same position from the image captured by the imaging unit 10 during the first period 41 and the image captured by the imaging unit 10 during the non-irradiation period. An image as a value is used for the first image 51. Further, the image processing unit 13 obtains a difference between pixel values of pixels at the same position from the image captured by the imaging unit 10 in the second period 42 and the image captured by the imaging unit 10 in the non-irradiation period. Is used as the second image 52.

  That is, the image processing unit 13 performs a pre-processing for removing noise prior to processing for generating the difference image 53 from the first image 51 and the second image 52. In the pre-processing, as described above, a difference between pixel values of pixels at the same position is obtained from the image captured by the imaging unit 10 in the first period 41 and the image captured by the imaging unit 10 in the non-irradiation period. An image using the difference as a pixel value is defined as a first image 51. Moreover, the difference of the pixel value of the pixel of the same position is calculated | required from the image which the imaging part 10 imaged in the 2nd period 42, and the image which the imaging part 10 imaged in the non-irradiation period, and this difference was made into the pixel value. Let the image be the second image 52.

  That is, the preprocessing removes the components of the image captured during the period of no light irradiation from the image captured using the light irradiated by the first irradiation unit 11, and the first image 51 is changed to the first image 51. Only the light component irradiated by one irradiation unit 11 is included. Similarly, the pre-processing removes the component of the image captured during the period of not irradiating light from the image captured using the light irradiated by the second irradiation unit 12, Only the light component irradiated by the second irradiation unit 12 is included.

  By performing the pre-processing described above, the first image 51 and the second image 52 contain almost no illumination light or natural light components. In addition, since the difference image 53 has the effect of reflection by the window glass 231 removed, the information included in the difference image 53 is almost only information related to the space region 211 of the outdoor 32. The technique of the present embodiment can be applied to any of the first embodiment, the second embodiment, and the third embodiment.

(Example of use)
Below, the operation | movement which detects the intruder in the space area 211 of the outdoor 32 using the difference image 53 which the image process part 13 produced | generated in embodiment mentioned above is demonstrated. In the following example, an intruder is an intruder, but another intruder may be used. Since the difference image 53 is an image of the space region 211 in the outdoor 32, it is possible to detect an intruder into the space region 211 by monitoring the change of the image over time. That is, the image processing unit 13 detects an intruder into the first space region 21 by using a plurality of difference images 53 obtained at different times and detecting a change in the difference image 53.

  Specifically, at least one of the two types of techniques described below is employed as a technique for monitoring changes over time. The first technique detects a moving object in the difference image 53 by using a plurality of frames of the difference image 53 and calculating a difference between the frames. In this case, the image processing unit 13 performs processing for extracting an edge for a plurality of frames of the difference image 53, performs a logical operation on pixels on the edge between adjacent frames, thereby removing background components and moving them. It is possible to extract only the edge of the object to be performed.

  This principle will be briefly described. Here, in order to simplify the description, an image (edge image) obtained by extracting an edge from two frames of consecutive difference images 53 is used, and the two-frame edge images are referred to as a first frame and a second frame in time order. . Further, it is assumed that each frame includes an edge of a moving object. Further, the pixel value of the edge image is binary, and can be used as a logical value of 1 and 0.

  In the first frame and the second frame, the edge of the stationary object is removed when the exclusive OR of the pixels is calculated between the two frames. Of the edge of the stationary object, the portion hidden by the moving object is not extracted, and therefore cannot be removed only by exclusive OR between two frames. However, when it is simply determined whether or not there is a moving object, there is no practical problem even if a part of the stationary object is included. As a result of obtaining the exclusive OR between two frames, if an edge remains (the total number of pixels may be obtained), it is determined that there is a moving object. If the logical product of the result of exclusive OR and other frames is used, it is possible to remove the edge of the stationary object hidden behind the moving object and extract only the edge of the moving object.

  The second technique uses a difference image 53 obtained when no intruder exists in the space area 211 as a background image, and uses the difference image 53 obtained thereafter as a target image, and calculates a difference between the target image and the background image. Using this, an object that has entered the space region 211 is detected. That is, the image processing unit 13 determines whether or not there is an intruder in the spatial region 211 by obtaining a difference between pixel values of pixels at the same position for the target image and the background image and evaluating the difference. To do. Since an intruder is considered to occupy a large area in the difference image 53 as compared with an animal such as a pet, the total of the differences obtained as described above or a region where a difference greater than a predetermined reference value has occurred. When the area is evaluated, it is possible to determine whether or not the person is an intruder. In addition, it may be determined whether or not the person is a person by recognizing the shape of the region where the difference occurs.

  The first technique and the second technique described above can be adopted as necessary, and the image processing unit 13 outputs a detection signal when a moving object or an intruder is detected. It may be configured. By using this detection signal for alarm notification, a monitoring device for an intruder or the like can be configured.

  In the above configuration example, the camera device 1 has been described with respect to the case where the imaging unit 10, the first irradiation unit 11, and the second irradiation unit 12 are provided integrally. The visual field 20 of the imaging unit 10, the first spatial region 21 illuminated by the first irradiation unit 11, and the second spatial region 22 illuminated by the second irradiation unit 12 have the same relationship as in the above configuration example. If so, the imaging unit 10, the first irradiation unit 11, and the second irradiation unit 12 may not be integrated.

DESCRIPTION OF SYMBOLS 1 Camera apparatus 10 Image pick-up part 10A 1st image pick-up part 10B 2nd image pick-up part 11 1st irradiation part 12 2nd irradiation part 13 Image processing part 14 Control part 20 Field of view 21 1st space area 22 2nd space Region 23 Transparent member 41 1st period 42 2nd period 51 1st image 52 2nd image 53 Difference image 103 2nd polarizing filter 112 Light emission part 113 1st polarizing filter 114 Reflective member 211 Spatial area

Claims (18)

An imaging unit having a visual field in a specific direction and outputting an image;
A first irradiation unit that irradiates light to a first spatial region that overlaps at least a part of the visual field;
A second irradiating unit that irradiates light to a second spatial region including other than the visual field;
When a transparent member is present in the field of view of the imaging unit, the first region is used to extract an image of a spatial region on the opposite side of the imaging unit from the image output by the imaging unit with respect to the transparent member. The first image captured by the imaging unit using the light irradiated by the irradiation unit and the second image captured by the imaging unit using the light irradiated by the second irradiation unit are used. Image processing for obtaining a difference image by multiplying at least one of the pixel values of two pixels at the same position by a predetermined correction coefficient for one image and the second image, and generating a difference image using the difference as a pixel value And
A controller that controls operations of the imaging unit, the first irradiation unit, the second irradiation unit, and the image processing unit;
The camera device, wherein the correction coefficient is set so as to reduce a component of light reflected by the transparent member from the first image. The first irradiation unit and the second irradiation unit are integrally coupled with the imaging unit,
The first irradiation unit irradiates light in the direction of the optical axis of the imaging unit,
The camera apparatus according to claim 1, wherein the second irradiating unit sets a spatial region excluding a field of view of the imaging unit as the second spatial region. The controller is
The first irradiating unit and the first irradiating unit are arranged such that the first period in which the first irradiating unit irradiates light and the second period in which the second irradiating unit irradiates light are different. 2. The imaging unit is controlled so as to control two irradiation units, capture the first image during the first period, and capture the second image during the second period. Or the camera apparatus of 2. The controller is
The camera device according to claim 3, wherein the first irradiation unit and the second irradiation unit are controlled so as to alternately generate the first period and the second period. The imaging unit
A first imaging unit that captures the first image during the first period;
A second imaging unit that captures the second image in the second period, and
The controller is
Outputting the second image from the second imaging unit in the first period,
The camera apparatus according to claim 3, wherein the first image is output from the first imaging unit during the second period. The camera device according to claim 1, wherein the second irradiation unit includes a plurality of light emitting units having different light emission directions. The first irradiation unit includes:
A light emitting unit for outputting light;
A first polarizing filter that passes linearly polarized light having a specific vibration surface out of the light output from the light emitting unit;
The camera device according to claim 1, wherein the imaging unit includes a second polarizing filter that allows light having a vibration surface in a direction intersecting with a vibration surface of linearly polarized light passing through the first polarizing filter to pass. The light emitting unit
A light source;
The camera device according to claim 7, further comprising: a reflection member that diffuses and reflects light emitted from the light source and reflected by the first polarizing filter in a direction toward the first spatial region. The controller is
Controlling the first irradiation unit and the second irradiation unit so as to provide a non-irradiation period in which neither the first irradiation unit nor the second irradiation unit emits light;
Controlling the imaging unit to image in the non-irradiation period in addition to the first period and the second period;
The image processing unit
From the image captured by the imaging unit during the first period and the image captured by the imaging unit during the non-irradiation period, a difference between pixel values of pixels at the same position is obtained, and an image using the difference as a pixel value is obtained. Used for the first image,
From the image captured by the imaging unit during the second period and the image captured by the imaging unit during the non-irradiation period, a difference between pixel values of pixels at the same position is obtained, and an image using the difference as a pixel value is obtained. The camera device according to claim 3, wherein the camera device is used for the second image. The imaging unit
The camera device according to claim 1, further comprising an optical filter that selectively transmits a wavelength of light emitted by the first irradiation unit and the second irradiation unit. The image processing unit
The camera device according to claim 1, further comprising a table in which the correction coefficient to be multiplied by a pixel value of at least one pixel of the first image and the second image is set according to a position of the pixel. The image processing unit
The camera device according to claim 1, wherein the difference image is generated by changing the correction coefficient, and the correction coefficient is employed when an evaluation value for the number of edges obtained from the difference image satisfies a predetermined condition. . The image processing unit
The camera apparatus according to claim 1, wherein the difference image is generated by varying the correction coefficient, and the correction coefficient is employed when an evaluation value for a pixel value obtained from the difference image satisfies a predetermined condition. The controller is
The camera device according to claim 1, wherein the first image and the second image are generated in units of one frame of the imaging unit. The controller is
The camera device according to claim 1, wherein the second image is acquired when a change in a pixel value of the first image that exceeds a predetermined reference value occurs. The controller is
The camera device according to claim 1, wherein the second image is acquired at a constant time interval. The first irradiating unit and the second irradiating unit have different wavelengths of light to be irradiated,
The imaging unit
A first imaging unit including a first optical filter that selectively transmits a wavelength of light emitted from the first irradiation unit;
A second imaging unit including a second optical filter that selectively transmits a wavelength of light emitted from the second irradiation unit;
The camera device according to claim 1, wherein the first image uses an image captured by the first imaging unit, and the second image uses an image captured by the second imaging unit. The image processing unit
The intruder into the first space region is detected by detecting a change in the difference image using a plurality of the difference images obtained at different times. The camera device described.