JP2010109562A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus obtaining images with reduced reflection of external light to the object even when a transparent or semi-transparent object is included in an object. <P>SOLUTION: The imaging apparatus 1000 includes: an imaging element 120 for generating object images; a polarization filter 130 for reducing the quantity of light of the object made incident on the imaging element 120; a reflected light determination part 151 for determining whether or not the luminance of the object image is equal to or higher than a threshold preset for determining whether or not the reflection phenomenon of the external light on the transparent or translucent object interposed between an imaging target included in the object and the imaging element 120 is generated in the object image; and an image processing part 150 for generating the correction image of the object image using the light of the object with incident light quantity reduced by the polarization filter 130 when the reflected light determination part 151 determines that the luminance of the object image is equal to or more than the threshold. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus that suppresses reflection of external light onto an object included in a subject using a polarizing filter.

  As a general imaging device, it has an imaging device such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) and a lens for condensing the subject image, and the subject image condensed by the lens is obtained. What is imaged with an image sensor is widely known as two-dimensional image information. Further, in a general imaging device, a polarizing filter is disposed to face the imaging surface of the imaging device, and the light of the subject is polarized by the polarizing filter.

Patent Document 1 discloses an in-vehicle stereo camera that captures a scene in front of a windshield with a camera attached to a vehicle body. In the in-vehicle stereo camera described in Patent Document 1, a polarizing filter is mounted on the front surface of the camera. In this polarizing filter, the polarization axis has an offset angle determined according to the curvature in the vertical direction of the windshield. Thus, by giving the offset angle to the polarization axis, reflection of the upper part of the instrument panel due to reflection on the inside of the windshield can be suppressed.
JP 2001-94842 A

  However, depending on the use of the image pickup device, it is not limited to the inside of the windshield of a car as described in Patent Document 1, but is transparent or translucent to reflect light, such as building glass, glasses, and a water pool on the road surface. In some cases, a reflective object is imaged. At this time, for example, light from an external light source such as sunlight, moonlight, a car headlight, and indoor lighting and its reflected light are incident on the image sensor at an angle at which it strikes a reflecting object. As a result, there are cases where external light is reflected on a reflecting object and a desired imaging target cannot be imaged clearly. In particular, when the brightness of outside light is extremely high, the brightness level is saturated when the outside light enters the image sensor, and the imaging target cannot be imaged.

  For example, an imaging device that senses the condition of a road surface or a center line in front of the vehicle and provides the driver with the sensing result, or an image that monitors the surrounding area including the blind spot of the vehicle and provides the driver with the monitoring result. When the external light is reflected on the road surface wetted by raindrops and enters the image sensor, and the external light is reflected on the wet road surface, and the surface of the road surface or the center line that is the imaging target cannot be imaged clearly. There is. In this case, the imaging device cannot provide information such as road surface conditions to the driver.

  Also, for example, in an imaging device that detects or recognizes after imaging a human face, eyes, pupils, line of sight, blinks, etc., external light is reflected by the surface of the spectacles and enters the image sensor, and the external light is applied to the spectacles. In some cases, the face, eyes, pupils, and the like, which are imaging targets, cannot be captured clearly. In this case, the imaging device cannot detect or recognize the face, eyes, or pupil.

  The present invention has been made to solve the above-described conventional problems, and even when a subject includes a transparent or translucent object, an image in which reflection of external light on the object is suppressed can be obtained. It is an object of the present invention to provide an imaging device that can be used.

  An imaging device according to the present invention includes an imaging device that captures an image of a subject to generate a subject image, a polarization filter that reduces an incident light amount of light incident on the imaging device, and brightness of the subject image. A determination unit that determines whether or not an external light reflection phenomenon on a transparent or translucent object is greater than or equal to a preset threshold value for determining whether or not the subject image has occurred When the unit determines that the luminance of the subject image is equal to or higher than the threshold value, an image that generates a corrected image in which the luminance of the subject image is corrected using the light whose incident light amount is reduced by the polarization filter And a processing unit.

  With this configuration, when the luminance of the subject image is equal to or higher than the threshold, the determination unit can determine that the reflection phenomenon has occurred in the subject image. In this case, the image processing unit generates a corrected image in which the luminance of the subject image is corrected using the light whose incident light amount has been reduced by the polarization filter. Therefore, the subject includes a transparent or translucent object. In addition, it is possible to obtain an image in which the reflection of external light on the object is suppressed. For this reason, for example, even when a desired imaging target is located on the other side of the object as viewed from the imaging device side, an image obtained by clearly capturing the imaging target without being affected by the reflection of external light on the object Can be obtained.

  In the imaging device according to the present invention, the polarization filter is configured by a plurality of partial polarization films corresponding to a unit area which is a processing unit of image processing in the subject image, and is a determination unit in the determination unit. The plurality of partial polarization films corresponding to the reflection determination area configured by a plurality of unit areas have different polarization directions, and the determination unit determines whether the luminance of the reflection determination area is equal to or higher than the threshold value. The image processing unit determines an image of a unit area selected from the reflection determination area when the determination unit determines that the luminance of the reflection determination area is equal to or higher than the threshold value. And a configuration for generating the corrected image of the reflection determination area.

  With this configuration, when the luminance of the reflection determination area is equal to or higher than the threshold, the determination unit can determine that the reflection phenomenon occurs in the reflection determination area. In this case, a corrected image of the reflection determination area is generated using the image of the unit area selected from the reflection determination area. As a result, the luminance of the subject image is corrected only for the reflection determination area in the subject image that is determined to have the reflection phenomenon by the determination unit, and therefore it is determined that the reflection phenomenon has occurred. The brightness of the reflection determination area that did not exist is not reduced. In this way, since the luminance of the subject image is reduced only for the minimum necessary image area in the subject image, the reflection of external light on the object is suppressed without greatly reducing the luminance of the entire subject image. An image can be obtained.

  In the imaging device according to the present invention, the plurality of partial polarization films corresponding to the reflection determination area are a plurality of pairs of partial polarization films whose polarization directions are substantially orthogonal to each other, and the image processing unit is the determination unit. When it is determined that the brightness of the reflection determination area is equal to or higher than the threshold value, a pair with a partial polarization film corresponding to the unit area having the highest brightness among the plurality of unit areas in the reflection determination area is formed. The correction image of the reflection determination area is generated using an image of a unit area corresponding to the partial polarization film.

  With this configuration, for the reflection determination area in which the determination unit determines that the luminance of the reflection determination area is equal to or greater than the threshold, the polarization direction of the partial polarizing film corresponding to the unit area having the highest luminance in the reflection determination area In this direction, strong light is incident on the image sensor. By using the image of the unit area corresponding to the partial polarization film having the polarization direction substantially orthogonal to the partial polarization film as the correction image of the reflection determination area, the image of the unit area having the highest luminance is output as the correction image. Can be suppressed. Thereby, in the reflection determination area in which the determination unit determines that the luminance of the reflection determination area is equal to or higher than the threshold, reflection of external light onto the object can be suitably suppressed.

  In the imaging device according to the present invention, when the determination unit determines that the luminance of the reflection determination area is less than a threshold value, the image processing unit includes all unit areas in the reflection determination area. The corrected image of the reflection determination area is generated using a composite image.

  With this configuration, for the reflection determination area in which the determination unit determines that the luminance of the reflection determination area is less than the threshold value, the image processing unit converts the combined image of all unit areas in the reflection determination area into a corrected image. Use. Here, since the polarizing filter is composed of a plurality of pairs of partial polarizing films that are substantially orthogonal to each other, the images in the reflection determination area can be obtained by synthesizing all the images of the plurality of unit areas in the reflection determination area. It is possible to eliminate the influence of polarization on the.

  In the imaging device according to the present invention, the polarizing filter is configured to be held facing the imaging element. Thereby, an image pick-up element and a polarizing filter can be integrated, and an image pick-up device can be made simple. As a result, the number of parts can be reduced, and an inexpensive and small imaging device can be provided.

  The imaging apparatus according to the present invention further includes a filter attaching / detaching unit that switches between a mounting state in which the polarizing filter is disposed at a position facing the imaging surface of the imaging element and a non-mounting state in which the polarizing filter is not disposed at a position. The filter attaching / detaching unit places the polarizing filter in the wearing state when the determining unit determines that the luminance of the subject image is equal to or higher than the threshold value, and the determining unit determines that the luminance of the subject image is less than the threshold value. If it is determined that the polarizing filter is not attached, the polarizing filter is arranged in the non-wearing state.

  With this configuration, when the determination unit determines that the luminance of the subject image is equal to or higher than the threshold, it is possible to obtain an image in which light is incident on the image sensor through the polarization filter and the reflection of external light on the object is suppressed. . On the other hand, if the determination unit determines that the luminance of the subject image is less than the threshold, the light is incident on the image sensor without passing through the polarization filter, and the luminance of the subject image is not changed without using the polarization filter. A bright image can be obtained. As described above, by simple switching by the filter attaching / detaching unit, when the determination unit determines that the luminance of the subject image is equal to or higher than the threshold value, an image in which external light is not reflected on the object can be easily obtained. .

  In the imaging apparatus according to the present invention, when the determination unit determines that the luminance of the subject image is equal to or higher than the threshold, the polarization filter is rotated so that the luminance of the subject image is lowest. It has the structure provided with the filter rotation part which stops rotation of a polarizing filter.

  With this configuration, when the polarizing filter rotates, the amount of light incident on the image sensor can be reduced, and accordingly, reflection of external light onto the object can be suitably suppressed.

  In the present invention, the luminance of the subject image is equal to or higher than a preset threshold value for determining whether or not the phenomenon of external light reflection on a transparent or translucent object included in the subject occurs in the subject image. If the brightness of the subject image is determined to be equal to or higher than the threshold value, a corrected image obtained by correcting the brightness of the subject image using light whose incident light amount to the image sensor is reduced by the polarization filter is obtained. Therefore, even if a subject includes a transparent or semi-transparent object, an imaging device having an effect of being able to obtain an image in which reflection of external light on the object is suppressed can be provided. It is.

(First embodiment)
Hereinafter, an imaging apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the imaging apparatus according to the first embodiment of the present invention.
In FIG. 1, the imaging apparatus 1000 includes an imaging unit 100 and a sensor unit 200. The imaging unit 100 includes a lens unit 110, an imaging element 120, a polarizing filter 130, a preprocessing unit 140, an image processing unit 150, an output switching unit 160, an exposure control unit 170, and a drive processing unit 180. I have.

  The lens unit 110 collects light of the subject and forms an image of the subject on the imaging surface of the image sensor 120. The image sensor 120 captures an image of a subject formed by the lens unit 110 and generates a subject image. The image sensor 120 is configured by a CCD (Charge Coupled Device). Note that the image sensor 120 may be a MOS (Metal Oxide Semiconductor) type image sensor.

  The polarizing filter 130 is provided between the lens unit 110 and the image sensor 120. The polarizing filter 130 reduces the amount of light incident on the image sensor 120. The polarizing filter 130 is held facing the image sensor 120 and constitutes an on-chip polarizing filter. Thereby, the image pick-up element 1000 and the polarizing filter 130 can be integrated, and the image pick-up device 1000 can be made into a simple structure.

  FIG. 2A shows the configuration of the subject image 300 captured by the image sensor 120, and FIG. 2B shows the planar configuration of the polarizing filter 130.

  First, the subject image 300 will be described with reference to FIG. The subject image 300 is subjected to image processing such as correction processing using a predetermined unit area as a processing unit. The unit area 301 corresponds to a single pixel or a plurality of pixels of the image sensor 120. In the example shown in FIG. 2A, the subject image 300 has unit areas 301 of 6 vertical × 6 horizontal. In addition, 2 × 2 four unit areas 301 constitute a reflection determination area 302 which is a determination unit in the reflected light determination unit 151. In FIG. 2A, for convenience of explanation, the outer peripheral line of the upper left reflection determination area 302 is highlighted. The size of the area for determining the reflection is not limited to 2 × 2 unit areas, and may be any size. For example, 4 × 4 = 16 unit areas may be used as the reflection determination area.

  Next, the polarizing filter 130 will be described with reference to FIG. The polarizing filter 130 includes a plurality of partial polarizing films 131 arranged corresponding to the unit area. The polarization directions of the plurality of partial polarization films corresponding to the reflection determination area are different from each other. In the present embodiment, the plurality of partial polarization films corresponding to the reflection determination area of the polarization filter 130 are composed of a plurality of pairs of partial polarization films whose polarization directions are substantially orthogonal to each other.

  In FIG. 2B, the partial polarization film in the highlighted block will be described as an example. In the partial polarizing film 131 in the block 132, the partial polarizing film (0 degree) 131 a and the partial polarizing film (90 degree) 131 b have a pair of polarization directions that are orthogonal to each other. The partial polarizing film (right oblique 45 degrees) 131c and the partial polarizing film (left oblique 45 degrees) 131d have a pair of polarization directions that are orthogonal to each other. The configuration of the subject image 300 and the polarization filter 130 has been described above.

  Returning to FIG. 1, the preprocessing unit 140 includes, for example, a correlated double sampling circuit (hereinafter referred to as a CDS (Correlated Double Sampling) circuit), an automatic gain correction circuit (hereinafter referred to as an AGC (Auto Gain Control) circuit), and An AD converter circuit (hereinafter referred to as an ADC (Analog / Digital Converter) circuit) or the like is used. The CDS circuit removes noise from the subject image generated by the image sensor 120, the AGC circuit performs AGC analog signal processing on the signal from the CDS circuit, and the ADC circuit converts the analog signal from the AGC circuit to a digital signal. Convert. The preprocessing unit 140 outputs the processed subject image data to the image processing unit 150 and the exposure control unit 170.

  The image processing unit 150 includes a reflected light determination unit 151, a reflected light control unit 152, and a signal processing unit 153. The image processing unit 150 generates a corrected image in which the luminance of the subject image 300 is corrected from the subject image data input from the preprocessing unit 140, and outputs the corrected image to the output switching unit 160. Specific image processing of the image processing unit 150 will be described in detail in the operation description described later.

  The reflected light determination unit 151 extracts luminance information from the data of the subject image 300 input from the preprocessing unit 140 for each reflection determination area 302. Further, the reflected light determination unit 151 determines whether or not the brightness of the reflection determination area 302 is equal to or higher than a threshold value. This threshold value is set in advance to determine whether or not a reflection phenomenon has occurred in the subject image. The threshold value is determined based on luminance information or the like when an image phenomenon actually occurs and is stored in the reflected light determination unit 151 or the like. The reflected light determination unit 151 corresponds to the determination unit of the present invention. A specific description of the reflected light determination unit 151 will be described in detail in the operation description described later.

  Here, the reflection phenomenon refers to a phenomenon in which external light is reflected on a transparent or translucent object such as a glass plate. In this case, external light includes not only sunlight and illumination light but also reflected light thereof. As an example of the reflection phenomenon, for example, a case where an object is reflected on the surface of a glass plate can be cited. For example, when a person standing on the other side of the glass plate is picked up by the image pickup apparatus 1000, if a reflection phenomenon occurs, the person who is the imaging target on the other side of the glass plate cannot be picked up clearly. Examples other than the glass plate include glasses and a puddle on the road surface. Similarly, when imaging the eye beyond the eyeglass as an imaging target, or when imaging the white line under a puddle on the road surface as an imaging target, it may not be possible to capture these imaging targets clearly. Can occur.

  The reflected light control unit 152 determines which of the four unit areas 301 in the reflection determination area 302 is based on the determination result of the reflected light determination unit 151 and the luminance of each unit area 301 in the reflection determination area 302. Whether to use the image of the unit area 301 for the correction image is determined for each reflection determination area 302. Specific contents of the reflected light control unit 152 will be described in detail in the operation description described later.

  The signal processing unit 153 is a circuit group that performs various types of signal processing on the corrected image data. Signal processing includes color separation, white balance, color difference signal (RY / BY) generation, gamma (γ) correction, knee processing, aperture processing, output clip processing, and the like. The signal processing unit 153 outputs the corrected image data after the signal processing to the output switching unit 160.

  The output switching unit 160 selects an output method such as NTSC (National Television Standards Committee), PAL (Phase Alternation by Line), or digital output, generates an output signal of a corrected image according to the selection result, and outputs the output signal to the sensor unit 200. Output to.

  The exposure control unit 170 calculates the exposure amount of the image sensor 120 based on the subject image data digitized by the preprocessing unit 140. The exposure control unit 170 controls the drive processing unit 180 such as adjusting the shutter speed according to the calculated exposure amount, and controls the preprocessing unit 140 such as adjusting the gain value.

  The drive processing unit 180 includes a vertical transfer drive circuit, a timing generator circuit, and the like. The drive processing unit 180 drives the image sensor 120 by adjusting the shutter speed and the like under the control of the exposure control unit 170.

  The sensor unit 200 is connected to the output switching unit 160 of the imaging unit 100. Based on the output signal of the corrected image output from the output switching unit 160, the sensor unit 200 detects an imaging target that is an imaging target from the subject image.

Next, the operation of the imaging apparatus 1000 according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG.
First, the image sensor 120 captures an image of a subject formed by the lens unit 110 to generate a subject image 300, and outputs this to the preprocessing unit 140. Specifically, the image sensor 120 converts incident light into an electric signal by photoelectric conversion, and outputs data of the subject image 300 to the preprocessing unit 140.

  The pre-processing unit 140 performs analog signal processing on the data of the subject image 300 by the CDS circuit and the AGC circuit, and then digitizes the data by the ADC circuit, and converts the digitized data of the subject image 300 to the image processing unit 150. And output to the exposure controller 170.

  The image processing unit 150 generates a corrected image in which the luminance of the subject image 300 is corrected from the data of the subject image 300 input from the preprocessing unit 140, and outputs the corrected image to the output switching unit 160.

Hereinafter, the operation of the image processing unit 150 will be described in detail with reference to FIGS. 1 and 2.
First, the reflected light determination unit 151 determines for each reflection determination area 302 whether the luminance of the reflection determination area 302 of the subject image 300 is equal to or higher than a preset threshold value.

  The threshold value is set in advance in order to determine whether or not a reflection phenomenon has occurred in the subject image. Therefore, when the reflected light determination unit 151 determines that the average luminance of the four unit areas 301 in the reflection determination area 302 is equal to or higher than the threshold, it is determined that the reflection phenomenon has occurred in the subject image 300. Become. On the other hand, when it is determined that the average luminance of the four unit areas 301 in the reflection determination area 302 is less than the threshold value, it is not determined that the reflection phenomenon has occurred in the subject image 300.

  In this way, since it is determined for each reflection determination area 302 whether or not a reflection phenomenon has occurred, the position information of the image area where the reflection phenomenon has occurred can be obtained for each reflection determination area 302. .

  In the above description, the reflected light determination unit 151 determines whether the average luminance of the four unit areas 301 in the reflection determination area 302 of the subject image 300 is equal to or higher than a threshold value. Reference numeral 151 denotes, for example, the luminance of the unit area having the highest luminance among the four unit areas 301 in the reflection determination area 302 of the subject image 300 and the four unit areas in the reflection determination area 302 of the subject image 300. It may be determined whether the difference in the average brightness of 301 is equal to or greater than a threshold value.

  Next, the reflected light control unit 152 determines the four unit areas 301 in the reflection determination area 302 based on the determination result of the reflected light determination unit 151 and the luminance of each unit area 301 in the reflection determination area 302. The unit area 301 to be used for the corrected image is determined for each reflection determination area 302.

  When the reflected light determination unit 151 determines that the luminance of the reflection determination area 302 is equal to or higher than the threshold, the reflected light control unit 152 has the luminance among the four unit areas 301 in the reflection determination area 302. It is determined that the image of the unit area 301 corresponding to the partial polarizing film 131 that forms a pair with the partial polarizing film 131 corresponding to the highest unit area 301 is used as the correction image. For example, in the example shown in FIG. 2A, when the luminance of the unit area 301c is the highest in the reflection determination area 302, the reflected light control unit 152 causes the partial polarizing film (right) to correspond to the unit area 301c. It is determined that the image of the unit area 301d corresponding to the partially polarizing film (left oblique 45 degrees) 131d paired with the (oblique 45 degrees) 131c is used as the correction image.

  On the other hand, when the reflected light determination unit 151 determines that the brightness of the reflection determination area 302 is less than the threshold value, the reflected light control unit 152 displays the image of the four unit areas 301 in the reflection determination area 302. A decision is made to use a synthesized image obtained by synthesizing all the images as a corrected image in the reflection determination area 302.

  The partial polarization film corresponding to the reflection determination area 302 is composed of a plurality of pairs of partial polarization films that are substantially orthogonal to each other. Therefore, by combining all the images of the four unit areas 301, The influence of polarization on the composite image can be eliminated.

  Next, the image processing unit 150 generates a correction image of the reflection determination area 302 using the unit area image determined by the reflected light control unit 152, and the signal processing unit 153 performs a predetermined process on the correction image data. The signal processing is performed, and the corrected image data after the signal processing is output to the output switching unit 160. The output switching unit 160 outputs the corrected image data to the sensor unit 200 in a desired output format. Based on the output signal of the corrected image output from the output switching unit 160, the sensor unit 200 detects an imaging target that is an imaging target from the subject image.

  Note that the exposure control unit 170 calculates the exposure amount of the image sensor 120 based on the subject image data digitized by the preprocessing unit 140. After that, the exposure control unit 170 controls the drive processing unit 180 such as adjusting the shutter speed according to the calculated exposure amount, and controls the preprocessing unit 140 such as adjusting the gain value. The drive processing unit 180 drives the image sensor 120 by adjusting the shutter speed and the like under the control of the exposure control unit 170.

  According to the imaging apparatus 1000 of the first embodiment of the present invention, the reflected light determination unit 151 determines that a reflection phenomenon has occurred in the subject image 300 when the luminance of the subject image 300 is equal to or higher than a threshold value. can do. In this case, the image processing unit 150 generates a corrected image in which the luminance of the subject image 300 is corrected using the light whose incident light amount has been reduced by the polarization filter 130, so that a transparent or translucent object is formed on the subject. Even if included, it is possible to obtain an image in which the reflection of external light on the object is suppressed. For this reason, for example, even when the imaging target that is a desired imaging target is located on the far side of the object as viewed from the imaging device 120 side, the imaging target is not affected by the reflection on the object. A clearly captured image can be obtained. As a result, the sensor unit 200 can efficiently detect the imaging target from the image.

  Further, according to the imaging apparatus 1000 of the first embodiment of the present invention, when the reflected light determination unit 151 determines that the brightness of the reflection determination area 302 is equal to or higher than the threshold, Thus, a corrected image of the reflection determination area 302 is generated using the image of the unit area 301 selected in order to efficiently suppress the reflection of outside light on the object. As a result, the luminance of the subject image 300 is corrected only for the reflection determination area 302 in the subject image 300 where the reflection light determination unit 151 determines that the reflection phenomenon has occurred. The brightness of the reflection determination area 302 that has not been determined to have occurred does not decrease. As described above, since the luminance of the subject image 300 is reduced only for the minimum necessary image area in the subject image 300, the external light is reflected on the object without greatly reducing the luminance of the entire subject image 300. Can be obtained.

  Further, according to the imaging apparatus 1000 of the first embodiment of the present invention, for the reflection determination area 302 that the reflected light determination unit 151 determines that the luminance of the reflection determination area 302 is greater than or equal to the threshold value, The image processing unit 150 uses the image of the unit area 301 corresponding to the partial polarizing film 131 that is paired with the partial polarizing film 131 corresponding to the unit area 301 having the highest luminance in the reflection determination area 302 as a correction image. The image of the unit area 301 having the highest luminance can be prevented from being output as a corrected image. Thereby, in the reflection determination area 302 in which it is determined that the luminance of the reflection determination area 302 is equal to or higher than the threshold value, reflection of external light on the object can be suitably suppressed.

  Further, according to the imaging apparatus 1000 of the first embodiment of the present invention, for the reflection determination area 302 that the reflected light determination unit 151 determines that the luminance of the reflection determination area 302 is less than the threshold value, The image processing unit 150 uses a composite image of all the unit areas 301 in the reflection determination area 302 as a corrected image. By synthesizing all the images of the unit area 301 corresponding to a plurality of pairs of partial polarization films that are substantially orthogonal to each other, the influence of polarization on the image in the reflection determination area 302 can be reduced. Thereby, in the reflection determination area 302 that the reflected light determination unit 151 determines that the luminance of the reflection determination area 302 is less than the threshold value, the influence of polarization by the polarization filter 130 can be suitably suppressed.

  Further, according to the imaging apparatus 1000 of the first embodiment of the present invention, the polarization filter 130 is held facing the imaging element 120. Thereby, the imaging device 120 and the polarizing filter 130 can be integrated, and the imaging device 1000 can be made into a simple structure. As a result, the number of parts can be reduced, and an inexpensive and small imaging device can be provided.

(Second Embodiment)
Hereinafter, an imaging apparatus according to a second embodiment of the present invention will be described with reference to the drawings.
FIG. 3 is a block diagram illustrating a configuration of an imaging apparatus 1100 according to the second embodiment of this invention.
In FIG. 3, an imaging apparatus 1100 includes an imaging unit 100a and a sensor unit 200a. The imaging unit 100a includes a lens unit 110, an imaging element 120, a polarizing filter 130a, a preprocessing unit 140, an image processing unit 150a, an output switching unit 160, an exposure control unit 170, an exposure execution unit 180, An attachment / detachment control unit 190. The sensor unit 200 a includes a reflected light determination unit 210.

  Comparing FIG. 1 and FIG. 3, as shown in FIG. 1, in the imaging apparatus 1000 according to the first embodiment, the polarization filter 130 is always disposed to face the imaging element 120. As shown in FIG. 3, in the imaging apparatus 1100 according to the second embodiment, the polarizing filter 130a is provided so as to be movable between a mounted state and a non-mounted state by a filter attaching / detaching unit 190. Is different.

  Further, in the imaging apparatus 1000 according to the first embodiment, the reflected light determination unit 151, the reflected light control unit 152, and the signal processing unit 153 are provided in the image processing unit 150, whereas the second embodiment. The imaging apparatus 1100 according to the embodiment is different in that only the signal processing unit 153 is provided in the image processing unit 150a. Further, the imaging apparatus 1100 according to the second embodiment is different in that the reflected light determination unit 210 is provided in the sensor unit 200a. Further, unlike the polarizing filter 130 of the imaging device 1000, the polarizing filter 130a of the imaging device 1100 has a uniform polarization direction.

  The polarizing filter 130 a reduces the amount of incident light of the subject incident on the image sensor 120. The filter attaching / detaching unit 190 moves the polarizing filter 130a based on the determination result of the reflected light determining unit 210 described later. The filter attaching / detaching unit 190 arranges the polarizing filter 130a at a position facing the imaging surface of the image sensor 120 or a position not facing the imaging surface. A state in which the polarizing filter 130a is disposed at a position facing the imaging surface of the image sensor 120 is referred to as a mounted state, and a state in which the polarizing filter 130a is disposed at a position not facing the imaging surface of the image sensor 120 is referred to as a non-mounted state. . In the present embodiment, the polarizing filter 130a is disposed between the lens unit 110 and the image sensor 120. However, the lens unit 110 may be disposed between the polarizing filter 130a and the image sensor 120.

  The sensor unit 200a is connected to the output switching unit 160 of the imaging unit 100. Based on the output signal of the corrected image output from the output switching unit 160, the sensor unit 200a detects an imaging target that is an imaging target from the subject image.

  The reflected light determination unit 210 extracts luminance information of the subject image from the subject image data. The reflected light determination unit 210 determines whether the luminance of the subject image is equal to or higher than a threshold value. This threshold value is set in advance to determine whether or not a reflection phenomenon has occurred in the subject image. The threshold value is determined based on luminance information and the like when an actual reflection phenomenon occurs, and is stored in the reflected light determination unit 210. Details of the reflected light determination unit 210 will be described later in the operation description. The reflected light determination unit 210 outputs the determination result to the filter attaching / detaching unit 190. The reflected light determination unit 210 corresponds to the determination unit of the present invention. Note that the average luminance of the subject image, the highest luminance in the subject image, or the like is used as the luminance of the subject image.

  The filter attaching / detaching unit 190 switches between the mounted state and the non-mounted state based on the determination result of the reflection determining unit 210. Specifically, when the reflected light determination unit 210 determines that the luminance of the subject image is equal to or higher than the threshold value, the filter attaching / detaching unit 190 switches to the mounted state. On the other hand, when the reflected light determination unit 210 determines that the luminance of the subject image is less than the threshold value, the filter attaching / detaching unit 190 switches to the non-attached state.

  The image processing unit 150 a includes a signal processing unit 153. The image processing unit 150 a generates a corrected image in which the luminance of the subject image is corrected from the subject image data input from the preprocessing unit 140, and outputs the corrected image to the output switching unit 160.

Next, the operation of the imaging apparatus 1100 according to the second embodiment of the present invention will be described based on the drawings.
The image sensor 120 captures the subject image formed by the lens unit 110 to generate a subject image, and outputs the subject image to the preprocessing unit 140. The pre-processing unit 140 performs predetermined processing on the subject image data, and outputs the subject image data to the image processing unit 150 a and the exposure control unit 170. The image processing unit 150a generates a corrected image obtained by correcting the luminance of the subject image from the subject image data input from the preprocessing unit 140, and the signal processing unit 153 performs predetermined signal processing on the corrected image data. Then, the corrected image data after the signal processing is output to the output switching unit 160. The output switching unit 160 outputs subject image data to the sensor unit 200a in a desired output format. Based on the output signal of the corrected image output from the output switching unit 160, the sensor unit 200a detects an imaging target that is an imaging target from the subject image.

  Here, the reflected light determination unit 210 extracts the luminance information of the subject image from the subject image data acquired by the sensor unit 200a. Then, the reflected light determination unit 210 determines whether or not the luminance of the subject image is equal to or higher than the threshold value, and outputs the determination result to the filter attaching / detaching unit 190.

  The filter attaching / detaching unit 190 switches between the mounted state and the non-mounted state based on the determination result of the reflected light fixing unit 210. Specifically, when the reflected light determination unit 210 determines that the luminance of the subject image is equal to or higher than the threshold value, the filter attaching / detaching unit 190 switches the polarizing filter 130 to the wearing state. Thereby, the light of the subject condensed by the lens unit 110 enters the imaging surface of the imaging device 120 through the polarizing filter 130a.

  On the other hand, when the reflected light determination unit 210 determines that the luminance of the subject image is less than the threshold value, the filter attaching / detaching unit 190 switches to the non-attached state. Thereby, the light of the subject condensed by the lens unit 110 enters the imaging surface of the imaging element 120 without passing through the polarizing filter 130a.

  According to the imaging apparatus of the second embodiment of the present invention, the filter attachment / detachment unit 190 switches between the mounted state and the non-mounted state based on the determination result of the reflected light determination unit 210. When the determination unit 210 determines that the luminance of the subject image is equal to or higher than the threshold, light is incident on the imaging surface of the image sensor 120 through the polarizing filter 130a, and the luminance of the subject image is reduced using the polarizing filter 130a. An image in which the reflection of external light on the object is suppressed can be obtained. On the other hand, when the reflected light determination unit 151 determines that the luminance of the subject image is less than the threshold, the light is incident on the imaging surface of the image sensor 120 without passing through the polarization filter 130a, and the polarization filter 130a is not used. A bright image can be obtained without changing the luminance of the subject image. As described above, when the reflected light determination unit 210 determines that the luminance of the subject image is equal to or higher than the threshold by simple switching by the filter attaching / detaching unit 190, an image in which the reflection of outside light on the object is suppressed can be easily performed. Obtainable.

  In the above description of the embodiment, it has been described that the reflected light determination unit 210 is provided in the sensor unit 200a. However, the reflected light determination unit 210 may be provided in the signal processing unit 150a. In this case, the reflection determination unit 210 extracts the luminance information of the subject image from the subject image data output from the preprocessing unit 140, and the reflection phenomenon is detected based on the luminance of the extracted subject image. It is determined whether or not it occurs in the image.

(Third embodiment)
Hereinafter, an imaging apparatus according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a block diagram showing a configuration of an imaging apparatus according to the third embodiment of the present invention.
In FIG. 4, the imaging device 1200 includes an imaging unit 100b and a sensor unit 200b. The imaging unit 100b includes a lens unit 110, an imaging element 120, a polarizing filter 130a, a preprocessing unit 140, an image processing unit 150a, an output switching unit 160, an exposure control unit 170, an exposure execution unit 180, And a filter rotating unit 191. The sensor unit 200b includes a reflected light determination unit 210a.

  3 and FIG. 4, as shown in FIG. 3, the imaging apparatus 1100 according to the second embodiment includes the filter attaching / detaching unit 190, whereas as shown in FIG. 4, An imaging apparatus 1200 according to the third embodiment is different in that it includes a filter rotating unit 191 instead of the filter attaching / detaching unit 190.

  The filter rotation unit 191 is a control mechanism that rotates the polarizing filter 130 a in a state of facing the imaging element 120. The filter rotation unit 191 receives the determination result of the reflected light determination unit 210. The filter rotation unit 191 rotates the polarization filter 130 based on the determination result of the reflected light determination unit 210a to change the polarization direction with respect to the incident light.

  The sensor unit 200b is connected to the output switching unit 160 and the exposure control unit 170 of the imaging unit 100b. Based on the output signal of the corrected image output from the output switching unit 160, the sensor unit 200b detects an imaging target that is an imaging target from the subject image.

  The reflected light determination unit 210a determines whether the luminance of the subject image is equal to or higher than the threshold value, and outputs the determination result to the filter rotation unit 191. The specific determination process of the reflected light determination unit 210a is the same as that described in the second embodiment. Further, while the filter rotation unit 191 rotates the polarizing filter 130a, the reflected light determination unit 210a extracts the luminance information of the subject image from the subject image data acquired by the sensor unit 200b. Then, the reflected light determination unit 210a controls the filter rotation unit 191 to stop the rotation of the polarization filter 130a in the direction in which the luminance of the subject image is the lowest. The reflected light determination unit 210a corresponds to the determination unit of the present invention.

  Next, the operation of the imaging apparatus 1200 according to the third embodiment of the present invention will be described based on the drawings. In the following description, operations different from those of the second embodiment of the present invention will be mainly described.

  The reflected light determination unit 210a extracts information on the luminance of the subject image from the subject image data acquired by the sensor unit 200b. Then, the reflected light determination unit 210a determines whether or not the luminance of the subject image is equal to or higher than the threshold value, and outputs the determination result to the filter rotation unit 191.

  Next, the filter rotating unit 191 rotates the polarizing filter 130a based on the determination result of the reflected light fixing unit 210a. Specifically, when the reflected light determination unit 210a determines that the luminance of the subject image is equal to or higher than the threshold, the filter rotation unit 191 rotates the polarization filter 130a. Thus, the polarization direction with respect to the light incident on the image sensor 120 can be changed by rotating the polarization filter 130a.

  The reflected light determination unit 210a extracts the luminance information of the subject image from the subject image data acquired by the sensor unit 200b while the filter rotation unit 191 rotates the polarizing filter 130a. Then, the reflected light determination unit 210a controls the filter rotation unit 191 to stop the rotation of the polarization filter 130a in the direction in which the luminance of the subject image is the lowest. The filter rotation unit 191 stops the rotation of the polarization filter 130a in the direction in which the luminance of the subject image is the lowest according to the control of the reflected light determination unit 210a.

  According to the imaging apparatus of the third embodiment of the present invention, when the reflected light determination unit 210a determines that the luminance of the subject image is equal to or higher than the threshold, the polarization filter 130a is rotated so that the luminance of the subject image is the highest. By stopping the rotation of the polarizing filter 130a in the low direction, the amount of light incident on the image sensor 120 can be reduced to the minimum, and thereby, the reflection of external light onto the object can be suitably suppressed. it can.

  In this embodiment, the reflected light determination unit 210a is described as being provided in the sensor unit 200b. However, the reflected light determination unit 210a may be provided in the signal processing unit 150a. In this case, the reflection determination unit 210a extracts information on the luminance of the subject image from the subject image data output from the preprocessing unit 140, and the reflection phenomenon is detected based on the luminance of the extracted subject image. It is determined whether or not it occurs in the image.

(Fourth embodiment)
Hereinafter, an imaging device according to a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a block diagram showing a configuration of an imaging apparatus according to the fourth embodiment of the present invention.
In FIG. 5, the imaging device 1300 includes an imaging unit 100c and a sensor unit 200c. The imaging unit 100c includes a lens unit 110, an imaging element 120, a polarizing filter 130a, a preprocessing unit 140, an image processing unit 150a, an output switching unit 160, an exposure control unit 170, an exposure execution unit 180, A filter attaching / detaching portion 190 and a filter rotating portion 191 are provided. The sensor unit 200c includes a reflected light determination unit 210b.

  3, 4, and 5 are compared, the imaging apparatus 1300 according to the fourth embodiment includes the second and third components in that both the filter attaching / detaching unit 190 and the filter rotating unit 191 are provided. It is different from the imaging devices 1100 and 1200 according to the embodiment.

  Similar to the imaging device 1100 of the second embodiment, the filter attaching / detaching unit 190 moves the polarization filter 130a based on a determination result of a reflected light determination unit 210b described later, thereby removing the mounting state and the mounting state described above. Switch between states.

  The filter rotation unit 191 is a control mechanism that rotates the polarizing filter 130a, as in the imaging device 1200 of the third embodiment. The filter rotation unit 191 receives the determination result of the reflected light determination unit 210b. The filter rotation unit 191 rotates the polarization filter 130a based on the determination result of the reflected light determination unit 210b to change the polarization direction with respect to the incident light.

  The reflected light determination unit 210b extracts information on the luminance of the subject image from the output data of the subject image. The reflected light determination unit 210b determines whether the luminance of the subject image is equal to or higher than the threshold value, and outputs the determination result to the filter attaching / detaching unit 190 and the filter rotating unit 191. The specific determination process of the reflected light determination unit 210b is the same as that described in the second embodiment. Further, while the filter rotation unit 191 rotates the polarizing filter 130a, the reflected light determination unit 210b extracts the luminance information of the subject image from the subject image data acquired by the sensor unit 200c. Then, the reflected light determination unit 210b controls the filter rotation unit 191 to stop the rotation of the polarization filter 130a in the direction in which the luminance of the subject image is the lowest. The reflected light determination unit 210b corresponds to the determination unit of the present invention.

Next, the operation of the imaging apparatus 1300 according to the fourth embodiment of the present invention will be described with reference to the drawings. In the following description, operations different from those of the second and third embodiments of the present invention will be mainly described.
The reflected light determination unit 210b extracts the luminance information of the subject image from the subject image data acquired by the sensor unit 200c. Then, the reflected light determination unit 210b determines whether or not the luminance of the subject image is equal to or higher than the threshold value, and outputs the determination result to the filter attaching / detaching unit 190 and the filter rotating unit 191.

  Next, when the reflected light determining unit 210b determines that the luminance of the subject image is equal to or higher than the threshold, the filter attaching / detaching unit 190 switches the polarizing filter 130a to the mounted state. In addition, the filter rotating unit 191 rotates the polarizing filter 130a in the mounted state.

  The reflected light determination unit 210b extracts the luminance information of the subject image from the subject image data acquired by the sensor unit 200c while the filter rotation unit 191 rotates the polarizing filter 130a. Then, the reflected light determination unit 210b controls the filter rotation unit 191 to stop the rotation of the polarization filter 130a in the direction in which the luminance of the subject image is the lowest. The filter rotation unit 191 stops the rotation of the polarization filter 130a in the direction in which the luminance of the subject image is the lowest according to the control of the reflected light determination unit 210b. As a result, the amount of incident light of the subject to the image sensor 120 can be reduced to a minimum, and reflection of external light onto the object can be suitably suppressed.

  On the other hand, when the reflected light determination unit 210b determines that the luminance of the subject image is less than the threshold, the filter attaching / detaching unit 190 switches the polarization filter 130a to the non-attached state. At this time, the filter rotating unit 191 does not operate. As a result, the light of the subject condensed by the lens unit 110 is incident on the imaging surface of the image sensor 120 without passing through the polarizing filter 130a, and thus a bright and clear image can be obtained without changing the luminance of the subject image. Can do.

  According to the imaging apparatus 1300 according to the fourth embodiment of the present invention, the effects produced by the imaging apparatuses 1100 and 1200 according to the second and third embodiments described above can be obtained together.

  In the above description of the embodiment, the reflected light determination unit 210b is described as being provided in the sensor unit 200c. However, the reflected light determination unit 210b may be provided in the signal processing unit 150a. In this case, the reflection determination unit 210b extracts information on the luminance of the subject image from the subject image data output from the preprocessing unit 140, and the reflection phenomenon is detected based on the luminance of the extracted subject image. It is determined whether or not it occurs in the image.

  The embodiments of the present invention have been described above by way of example, but the scope of the present invention is not limited to these embodiments, and can be changed or modified in accordance with the purpose within the scope of the claims. is there.

  As described above, the present invention has an effect that even if a subject includes a transparent or translucent object, an image in which reflection of external light on the object is suppressed can be obtained. This is useful for an imaging device that suppresses reflection of external light onto an object included in a subject. The present invention, for example, senses the condition of the road surface and centerline in front of the vehicle, provides the driver with the sensing result, and monitors the surroundings including the blind spot of the vehicle, and monitors the monitoring result. Particularly useful for imaging devices for detecting or recognizing an imaging target, such as imaging devices provided to the user, or imaging devices that detect or recognize human faces, eyes, pupils, eyes, blinks, etc. It is. Representative examples of the imaging device include a digital still camera, a digital video camera, and the like, and a system device including one or more of these.

1 is a block diagram illustrating a configuration of an imaging apparatus according to a first embodiment of the present invention. The figure which shows the structure of the to-be-photographed image and polarization filter imaged with the image pick-up element of the imaging device of the 1st Embodiment of this invention The block diagram which shows the structure of the imaging device of the 2nd Embodiment of this invention. The block diagram which shows the structure of the imaging device of the 3rd Embodiment of this invention. The block diagram which shows the structure of the imaging device of the 4th Embodiment of this invention.

Explanation of symbols

100, 100a, 100b, 100c Imaging unit 110 Lens unit 120 Imaging element 130, 130a Polarizing filter 131 Partially modified film 132 Block 140 Preprocessing unit 150, 150a Image processing unit 151, 210, 210a, 210b Reflected light determination unit 152 Reflected light Control unit 153 Signal processing unit 160 Output switching unit 170 Exposure control unit 180 Drive processing unit 190 Filter attaching / detaching unit 191 Filter rotating unit 200, 200a, 200b, 200c Sensor unit 1000, 1100, 1200, 1300 Imaging device

Claims (7)

An image sensor that images a subject and generates a subject image;
A polarizing filter that reduces the amount of incident light incident on the image sensor;
Whether the luminance of the subject image is equal to or higher than a threshold value set in advance to determine whether or not the phenomenon of external light being reflected on a transparent or translucent object included in the subject occurs in the subject image A determination unit for determining whether or not,
When the determination unit determines that the luminance of the subject image is equal to or higher than the threshold value, a corrected image is generated by correcting the luminance of the subject image using light whose incident light amount has been reduced by the polarization filter. And an image processing unit. The polarization filter is configured by a plurality of partial polarization films corresponding to a unit area which is a processing unit of image processing in the subject image, and is configured by a plurality of unit areas which are determination units in the determination unit. The plurality of partial polarization films corresponding to the reflection determination area have different polarization directions.
The determination unit determines whether or not the brightness of the reflection determination area is equal to or higher than the threshold,
The image processing unit uses the image of the unit area selected from the reflection determination area when the determination unit determines that the luminance of the reflection determination area is equal to or higher than the threshold. The imaging apparatus according to claim 1, wherein the corrected image in the determination area is generated. The plurality of partial polarization films corresponding to the reflection determination area are a plurality of pairs of partial polarization films whose polarization directions are substantially orthogonal to each other.
When the determination unit determines that the luminance of the reflection determination area is equal to or higher than the threshold, the image processing unit sets the unit area having the highest luminance among the plurality of unit areas in the reflection determination area. The imaging apparatus according to claim 2, wherein the correction image of the reflection determination area is generated using an image of a unit area corresponding to the partial polarization film that forms a pair with the corresponding partial polarization film.   When the determination unit determines that the luminance of the reflection determination area is less than the threshold, the image processing unit uses the combined image of all unit areas in the reflection determination area to determine the reflection determination. The imaging apparatus according to claim 2, wherein the corrected image of the area is generated.   The imaging apparatus according to claim 1, wherein the polarizing filter is held facing the imaging element. A filter attaching / detaching unit that switches between a mounting state in which the polarizing filter is disposed at a position facing the imaging surface of the image sensor and a non-mounting state in which the polarizing filter is not disposed at a position;
The filter attaching / detaching unit places the polarizing filter in the wearing state when the determining unit determines that the luminance of the subject image is equal to or higher than the threshold value, and the determining unit determines that the luminance of the subject image is the threshold value. The imaging apparatus according to claim 1, wherein the polarizing filter is disposed in the non-wearing state when it is determined that the polarization filter is less than a predetermined value.   When the determination unit determines that the luminance of the subject image is equal to or higher than the threshold, the filter rotation unit rotates the polarization filter and stops the rotation of the polarization filter in a direction in which the luminance of the subject image is the lowest. The imaging apparatus according to claim 1, further comprising:

Images