JP2009126391A - On-vehicle imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle imaging device providing proper images. <P>SOLUTION: An image mode switching part 23 is switchable among three imaging modes of: a normal mode in which the dynamic range of a camera 11 is a specified value, with an illuminator 14 off; a direct incident light mode in which the dynamic range of the camera 11 is greater than the specified value, with the illuminator 14 off; and a dark place mode in which the dynamic range of the camera 11 is greater than the specified value, with the illuminator 14 on in accordance with the results of detection by a halation detection part 22a and a state determination part 22b. Control signals are outputted to command the dynamic range of the camera 11 and the on/off state of the illuminator 14 according to each imaging mode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle imaging device.

Conventionally, for example, when adjusting the exposure of a camera that captures an occupant in a passenger compartment by using an aperture and an exposure time, the position of the face of the occupant being photographed is near the position of the occupant's face, such as sunlight entering through the vehicle window An imaging device is known in which an exposure frame is set at a position where light is not directly irradiated, and exposure is set according to the brightness of the exposure frame (see, for example, Patent Document 1).
JP 2006-264404 A

  By the way, in the imaging apparatus according to the above-described prior art, since the exposure is adjusted according to the brightness of the exposure frame, only the area within the exposure frame is vividly captured. If the brightness difference between the area inside the exposure frame and the area other than the exposure frame becomes large due to the irradiation, there is a risk that overexposure or blackout may occur in the area other than the exposure frame. There arises a problem that the state of a wide area in the vehicle interior cannot be accurately grasped in the state.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an in-vehicle imaging device capable of obtaining an appropriate captured image.

  In order to solve the above-described problems and achieve the object, an in-vehicle imaging device according to a first aspect of the present invention includes imaging means for imaging a vehicle interior (for example, the camera 11 in the embodiment), an in-vehicle area, In accordance with the brightness detection means (for example, the brightness detection unit 21 in the embodiment) for detecting the brightness of the outside area of the vehicle, and the brightness of the inside area and the brightness of the outside area detected by the brightness detection means, An imaging mode switching unit (for example, an imaging mode switching unit 23 in the embodiment) that switches the imaging mode of the imaging unit is provided.

  Furthermore, in the in-vehicle imaging device according to the second aspect of the present invention, the imaging mode switching unit switches the dynamic range of the imaging unit.

  Furthermore, the in-vehicle imaging device according to the third aspect of the present invention includes a light emitting unit (for example, the light emitter 14 in the embodiment) that illuminates the vehicle interior, and the imaging mode switching unit is configured to turn on the light emitting unit. Switch between and off.

  Furthermore, in the in-vehicle imaging device according to the fourth aspect of the present invention, the imaging mode switching means includes a normal mode in which the dynamic range is a predetermined value and the light emitting unit is off, and the dynamic range is greater than the predetermined value. At least three modes are switched between a direct light mode in which the light emitting unit is large and a dark mode in which the dynamic range is larger than the predetermined value and the light emitting unit is on.

  Furthermore, the vehicle-mounted imaging device according to the fifth aspect of the present invention is a whiteout detection unit that detects the occurrence of overexposure based on the luminance detected by the luminance detection unit (for example, overexposure detection in the embodiment). Unit 22a) and state determination means (for example, state determination unit 22b in the embodiment) for determining two states, a bright state and a dark state, based on the luminance detected by the luminance detection unit. The imaging mode switching means switches from the normal mode to the direct light mode when the occurrence of the overexposure is detected in the in-vehicle area by the overexposure detection means in the normal mode, and the direct light mode When the state determination means determines that the vehicle interior region is dark and the vehicle exterior region is bright, the normal mode is changed from the direct light mode. When the state determining means determines that the vehicle interior area is in a dark state and the vehicle exterior area is in a dark state in the direct light mode, the direct light mode is changed to the dark place mode. Switch to.

  Furthermore, the vehicle-mounted imaging device according to the sixth aspect of the present invention is a state determination unit (for example, an embodiment) that determines two states, a bright state and a dark state, based on the luminance detected by the luminance detection unit. In the normal mode, the imaging mode switching means switches from the normal mode to the dark place mode when the state determination means determines that the in-vehicle area is in a dark state. When the state determination means determines that the outside area is in a bright state in the dark place mode, the dark mode is switched to the normal mode.

According to the vehicle-mounted imaging device according to the first aspect of the present invention, it is possible to image a wide area in the vehicle interior in an optimal imaging mode in accordance with the brightness of the vehicle interior area and the vehicle exterior area.
Furthermore, according to the vehicle-mounted image pickup device according to the second aspect of the present invention, it is possible to obtain clear picked-up images in a wide area in the vehicle compartment while preventing overexposure.

Furthermore, according to the vehicle-mounted imaging device according to the third aspect of the present invention, desired visibility can be ensured by illuminating the vehicle interior.
Furthermore, according to the vehicle-mounted imaging device according to the fourth to sixth aspects of the present invention, desired visibility can be secured while preventing overexposure by switching between the modes.

Hereinafter, an in-vehicle imaging device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
For example, as shown in FIG. 1, the in-vehicle imaging device 10 according to the present embodiment includes an imaging device 13 including a camera 11 and an image processing unit 12, a light emitter 14, and a processing device 15.
Further, the processing device 15 includes, for example, a luminance detection unit 21, an image analysis unit 22 including a whiteout detection unit 22a and a state determination unit 22b, and an imaging mode switching unit 23.

For example, as shown in FIG. 2, the imaging device 13 is disposed together with a light emitter 14 on a roof rail (not shown) in the vicinity of a map lamp (not shown) in the passenger compartment.
The camera 11 includes a fish-eye lens (for example, an angle of view = 190 °), and can capture the vehicle interior and the outside world through the front, rear, and side windows in the visible light region and the infrared region.
Note that the imaging range of the camera 11 requires that the number of passengers can be grasped, for example, so as to include the rear seat while placing more emphasis on the front seat and, for example, grasp the degree of injury to the passenger during an accident, etc. It is necessary to be able to include parts with relatively high harm frequency (for example, each pillar, instrument panel, steering wheel, door panel, etc.), and for example, it is possible to grasp the accident form and occupant position. It is set to include the window and the operating range of the passenger.
Further, the installation position of the camera 11 is set to a position where the possibility that the camera 11 is damaged when a collision occurs is relatively low, for example, a position where the vehicle body deformation is small.
The image processing unit 12 performs predetermined image processing such as filtering and binarization processing on the captured image obtained by photographing with the camera 11 to generate image data including pixels of a two-dimensional array, and a processing device 15 is output.
The camera 11 is controlled by a control signal output from the processing device 15 and can change the dynamic range.

  The light emitter 14 includes, for example, a light emitting diode, a lamp, and the like, and can illuminate the vehicle interior in the visible light region and the infrared region, and is switched on and off by a control signal output from the processing device 15.

  The luminance detection unit 21 of the processing device 15 detects the luminance of each pixel of the image data P output from the imaging device 13, and for example, as shown in FIG. 3, the occupant's face and chest of the front seat in the vehicle interior are detected. For example, as shown in FIG. 4, a frequency distribution of luminance values is generated for the vehicle interior region A and the two vehicle exterior regions B <b> 1 and B <b> 2 including the outside through the side window of the vehicle.

  The image analysis unit 22 uses, for example, the following Table 1 for the frequency distribution of the luminance values (for example, luminance values = 0 to 255) for each of the areas A, B1, and B2 of the image data P output from the luminance detection unit 21. As shown in FIG. 5, the threshold value for the luminance value, for example, the dark state threshold value TH1 (for example, TH1 = 50) and the whiteout threshold value TH2 (for example, TH2 = 250), and the number of pixels in the predetermined luminance range with respect to the total number of pixels of the image data P A threshold for a ratio of (number of pixels), for example, a dark state ratio threshold SH1 (for example, SH1 = 50%) for a range of luminance values less than the dark state threshold TH1, and a whiteout ratio threshold for a range of luminance values greater than the whiteout threshold TH2. SH2 (for example, SH2 = 10%) is stored in advance.

  Of the image data P output from the luminance detection unit 21, the overexposure detection unit 22 a particularly has a frequency distribution of the luminance value (for example, luminance value = 0 to 255) in the vehicle interior area A. Whether or not the ratio of the number of pixels (number of pixels) in the brightness value range (out-of-range range) equal to or greater than the over-throw threshold TH2 to the over-all number of pixels is equal to or greater than the over-exposure ratio threshold SH2 (eg, SH2 = 10%). If this determination result is “YES”, it is determined that over-exposure has occurred. On the other hand, when the determination result is “NO”, it is determined that no over-exposure has occurred.

  The state determination unit 22b applies the image data P to the frequency distribution of the luminance values (for example, luminance values = 0 to 255) for each of the areas A, B1, and B2 of the image data P output from the luminance detection unit 21. It is determined whether or not the ratio of the number of pixels (number of pixels) in the luminance value range (dark state range) less than the dark state threshold TH1 to the total number of pixels is equal to or greater than the dark state ratio threshold SH1. If “YES”, it is determined that a dark state has occurred. On the other hand, when the determination result is “NO” for the in-vehicle area A and the over-exposure detector 22a determines that no over-out has occurred, the bright state in the in-vehicle area A When the determination result is “NO” for each of the vehicle exterior areas B1 and B2, it is determined that a bright state occurs in each of the vehicle exterior areas B1 and B2. .

  In accordance with the detection results of the overexposure detection unit 22a and the state determination unit 22b, the imaging mode switching unit 23 normally has a dynamic range of the camera 11 that is a predetermined value and the light emitter 14 is off, as shown in FIG. A direct light mode in which the dynamic range of the camera 11 is larger than a predetermined value and the light emitter 14 is off, and a dark place mode in which the dynamic range of the camera 11 is larger than a predetermined value and the light emitter 14 is on. The two imaging modes are switched, and a control signal for instructing the dynamic range of the camera 11 and the on / off states of the light emitter 14 is output according to each imaging mode.

  The in-vehicle imaging device 10 according to the present embodiment has the above-described configuration. Next, the operation of the in-vehicle imaging device 10, particularly the processing for switching the imaging mode will be described.

First, in step S01 shown in FIG. 6, it is determined whether or not the imaging mode is a dark place mode.
If this determination is “YES”, the flow proceeds to step S 08 described later.
On the other hand, if this determination is “NO”, the flow proceeds to step S 02.
In step S02, it is determined whether or not the imaging mode is the normal mode.
If the determination result in step S02 is “NO”, that is, if the imaging mode is the direct light mode, the process proceeds to step S11 described later.
On the other hand, if the determination result of step S02 is “YES”, the process proceeds to step S03.

In step S03, the luminance of each pixel of the image data P output from the imaging device 13 is detected, and the luminance value for each region A, B1, B2 of the image data P (for example, luminance value = 0 to 255). ) And a dark state, a bright state, and a whiteout state are determined for each of the regions A, B1, and B2.
In step S04, it is determined whether or not the in-vehicle area A is in an overexposed state.
If this determination is “YES”, the flow proceeds to step S 10 described later.
On the other hand, if this determination is “NO”, the flow proceeds to step S 05.

In step S05, it is determined whether or not the in-vehicle area A is in a dark state.
If this determination is “YES”, the flow proceeds to step S 06.
On the other hand, if this determination is “NO”, the flow returns to step S 03 described above.
In step S06, the dark place mode is set as the imaging mode.

In step S07, the luminance of each pixel of the image data P output from the imaging device 13 is detected, and the luminance value for each region A, B1, B2 of the image data P (for example, luminance value = 0 to 255). ) And a dark state, a bright state, and a whiteout state are determined for each of the regions A, B1, and B2.
In step S08, it is determined whether the vehicle interior area A and the vehicle exterior areas B1 and B2 are in a bright state.
If this determination is “YES”, the flow proceeds to step S09.
On the other hand, if this determination is “NO”, the flow returns to step S 07 described above.
In step S09, the normal mode is set as the imaging mode, and the series of processing ends.

In step S10, the direct light mode is set as the imaging mode.
In step S11, the luminance of each pixel of the image data P output from the imaging device 13 is detected, and the luminance value for each region A, B1, B2 of the image data P (for example, luminance value = 0 to 255). ) And a dark state, a bright state, and a whiteout state are determined for each of the regions A, B1, and B2.
In step S12, it is determined whether or not the in-vehicle area A is in a dark state.
If this determination is “YES”, the flow proceeds to step S13.
On the other hand, if this determination is “NO”, the flow returns to step S 11 described above.

In step S13, it is determined whether or not the vehicle exterior areas B1 and B2 are in a bright state.
If this determination is “YES”, the flow proceeds to step S 09 described above.
On the other hand, if this determination is “NO”, the flow proceeds to step S 06 described above.

  As a result, for example, in the execution state of the normal mode in which the areas A, B1, and B2 are bright as shown in FIGS. 5 and 7A and the example shown in Table 2 below, for example, FIGS. As in the embodiments shown in b) and Table 3 below, when it is determined that at least the vehicle interior area A is dark among the areas A, B1, and B2, the imaging mode is switched from the normal mode to the dark place mode. The dynamic range of the camera 11 is set to be larger than a predetermined value, and the light emitter 14 is switched from the off state to the on state. As a result, the vehicle interior area A changes from a dark state to a bright state, as in the examples shown in FIGS. 5 and 7C and Table 4 below, for example.

  Further, when it is determined that each of the vehicle exterior areas B1 and B2 is in a bright state in the execution state of the dark place mode in which the vehicle interior area A is in a bright state due to the light-emitting device 14 being on, imaging is performed. The mode is switched from the dark place mode to the normal mode, the control for making the dynamic range of the camera 11 larger than a predetermined value is stopped, and the light emitter 14 is switched from the on state to the off state.

  Further, for example, in the execution state of the normal mode in which the areas A, B1, and B2 are bright as shown in FIGS. 5 and 8A and the embodiment shown in Table 5 below, for example, FIGS. ) And the embodiment shown in Table 6 below, when it is determined that the in-vehicle area A is out of focus among the areas A, B1, and B2, the imaging mode is switched from the normal mode to the direct light mode. The dynamic range of the camera 11 is set to be larger than a predetermined value, and the light emitter 14 is switched so as to maintain the off state. As a result, for example, as shown in FIG. 5 and FIG. 8C and the example shown in Table 7 below, the in-vehicle area A changes from a whiteout state to a bright state.

Further, in the execution state of the direct light mode in which the in-vehicle area A is in a bright state due to the dynamic range of the camera 11 being larger than a predetermined value, the in-vehicle area A is in a dark state and the outside areas B1, B2 are in a bright state. Is determined, the imaging mode is switched from the direct light mode to the normal mode, the control for increasing the dynamic range of the camera 11 to be larger than a predetermined value is stopped, and the light emitter 14 is maintained in the off state. Are switched as follows. Thereby, the in-vehicle area A changes from a dark state to a bright state.
Further, in the execution state of the direct light mode in which the in-vehicle area A is in a bright state due to the dynamic range of the camera 11 being larger than a predetermined value, each of the areas A, B1, and B2 is determined to be in a dark state. Then, the imaging mode is switched from the direct light mode to the dark place mode, the control that the dynamic range of the camera 11 is larger than a predetermined value is maintained, and the light emitter 14 is switched from the off state to the on state. As a result, at least the vehicle interior area A changes from a dark state to a bright state.

As described above, according to the in-vehicle imaging device 10 according to the present embodiment, a wide area in the vehicle interior is sharpened in the optimal imaging mode according to the frequency distribution of the luminance values of the in-vehicle area A and the out-of-vehicle areas B1 and B2. Can be imaged.
Furthermore, desired visibility can be ensured by preventing the occurrence of overexposure by switching the imaging mode.

It is a block diagram of the vehicle-mounted imaging device which concerns on embodiment of this invention. It is a figure which shows the installation position of the camera which concerns on embodiment of this invention. It is a figure which shows the image data obtained by imaging | photography with the camera which concerns on embodiment of this invention. It is a figure which shows an example of frequency distribution of the luminance value of each pixel of the image data obtained by imaging | photography with the camera which concerns on embodiment of this invention. It is a figure which shows an example of the change of the image data according to switching to the normal mode which concerns on embodiment of this invention, a direct light mode, and a dark place mode. It is a flowchart which shows operation | movement of the vehicle-mounted imaging device which concerns on embodiment of this invention. It is a figure which shows an example of the change of the frequency distribution of the luminance value of each pixel of the image data according to switching from the normal mode to the dark place mode according to the embodiment of the present invention. It is a figure which shows an example of the change of the frequency distribution of the luminance value of each pixel of the image data according to switching from the normal mode to the direct light mode according to the embodiment of the present invention.

Explanation of symbols

10 on-vehicle imaging device 11 camera (imaging means)
14 Light emitter (light emitting part)
21 Luminance detection unit (luminance detection means)
22a White spot detection unit (white spot detection means)
22b State determination unit (state determination means)
23. Imaging mode switching unit (imaging mode switching means)

Claims (6)

Imaging means for imaging the passenger compartment;
Luminance detection means for detecting the luminance of the interior area and the exterior area;
An in-vehicle imaging device comprising: an imaging mode switching unit that switches an imaging mode of the imaging unit according to the luminance of the in-vehicle area and the luminance of the outside area detected by the luminance detecting unit. The in-vehicle imaging device according to claim 1, wherein the imaging mode switching unit switches a dynamic range of the imaging unit. A light emitting unit for illuminating the vehicle interior;
The in-vehicle imaging device according to claim 2, wherein the imaging mode switching unit switches on and off of the light emitting unit. The imaging mode switching means is
A normal mode in which the dynamic range is a predetermined value and the light emitting unit is off; and
A direct light mode in which the dynamic range is larger than the predetermined value and the light emitting unit is off;
The in-vehicle imaging device according to claim 3, wherein at least three modes are switched to a dark place mode in which the dynamic range is larger than the predetermined value and the light emitting unit is on. Based on the brightness detected by the brightness detection means, overexposure detection means for detecting occurrence of overexposure;
A state determination unit that determines two states, a bright state and a dark state, based on the luminance detected by the luminance detection unit;
The imaging mode switching means is
When the occurrence of the overexposure is detected in the in-vehicle region by the overexposure detection means in the normal mode, the normal mode is switched to the direct light mode,
In the direct light mode, when the state determination means determines that the vehicle interior region is in a dark state and the vehicle exterior region is in a bright state, the direct light mode is switched to the normal mode,
In the direct light mode, when the state determination means determines that the vehicle interior region is in a dark state and the vehicle exterior region is in a dark state, switching from the direct light mode to the dark place mode is performed. The in-vehicle imaging device according to claim 4, wherein the on-vehicle imaging device is characterized. Based on the brightness detected by the brightness detection means, comprising state determination means for determining two states, a bright state and a dark state,
The imaging mode switching means is
When the state determination means determines that the in-vehicle area is in a dark state in the normal mode, the normal mode is switched to the dark place mode,
5. The vehicle-mounted imaging device according to claim 4, wherein, in the dark place mode, when the state determining unit determines that the outside area is in a bright state, the dark mode is switched to the normal mode. 6. .

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