JP2009067096A - Headrest control device, headrest device, and headrest control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a headrest device capable of performing a position control of a headrest without being affected by disturbance light anytime during the day and night. <P>SOLUTION: This headrest device is provided with the headrest 21 suppressing backward inclination of a head portion B of an occupant A sitting on a vehicle seat and is constituted to control the position of the headrest 21. The headrest device is provided with a far-infrared imaging device 12 for imaging the occupant A, a means for detecting the position of the head portion B of the occupant A based on the far-infrared images imaged by the far-infrared imaging device 12, a means for detecting the position of the headrest 21, and a control device 11 for controlling the position of the headrest 21 so that relative positions of the head portion B and the headrest 21 may have a prescribed positional relation based on the detected positions of the head portion B and the headrest 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a headrest control device, a headrest device, and a headrest control method for performing headrest position control.

  A headrest device has been put into practical use that reduces the lashing injury of a passenger at the time of a rear collision of a vehicle (at the time of a rear-end collision by a rear vehicle) (for example, Patent Document 1). The headrest device can suppress a whiplash injury by suppressing a rearward tilt of the head of an occupant seated on the vehicle seat by a pillow-like headrest provided on the backrest of the vehicle seat.

  An active headrest that can drive the headrest by a motor has been proposed. The active headrest can effectively prevent the head from tilting backward by moving the headrest closer to the head at the time of a rear collision, and can reduce whiplash injury.

  Furthermore, a headrest device and a headrest control method that realize precise position adjustment of the headrest at a low cost have been proposed. Specifically, a capacitive head detector is provided in the headrest, the head detector detects the relative position between the head of the seated occupant and the headrest, and the headrest is set to the head position of the occupant. It is comprised so that it may move near. However, since the capacitance type head detector detects the head that is close to the headrest, the headrest may not be driven by accurately detecting the relative distance between the headrest and the head. is there.

In order to solve this problem, a headrest device has been proposed in which the head position is detected by a CCD image sensor that captures an occupant with visible light, and the headrest can be moved closer to the headrest.
Japanese Patent No. 2669588

However, since the CCD image sensor is an element that images the occupant with visible light, there is a problem that the occupant cannot be imaged at night and the position of the headrest cannot be controlled.
In addition, when disturbance light such as the sun or a headlight enters the vehicle, it is difficult to image the head, and there is a possibility that the position control of the headrest is erroneous.

  The present invention has been made in view of such circumstances, and provides a headrest control device, a headrest device, and a headrest control method capable of performing headrest position control regardless of daytime and nighttime and without being affected by ambient light. The purpose is to provide.

  A headrest control device according to a first aspect of the present invention is a headrest control device that controls the position of a headrest that suppresses backward tilting of the head of an occupant seated in a vehicle seat. Based on the position of the headrest of the occupant, the means for acquiring the position information indicating the position of the headrest, the position of the detected head and the position of the headrest indicated by the acquired position information And a control means for outputting a control signal for controlling the position of the headrest so that the relative position of the head and the headrest is in a predetermined positional relationship.

  A headrest control device according to a second aspect of the present invention is a headrest control device that controls the position of a headrest that suppresses backward tilting of the head of an occupant seated in a vehicle seat. Means for extracting edge points from the outer image, means for specifying an edge group consisting of a plurality of connected edge points, means for dividing an image area including the specified edge group into a plurality of small areas, and Means for identifying a corresponding area corresponding to the divided small area from the far-infrared image obtained by imaging by another far-infrared imaging device, and an image area having substantially the same parallax between the small area and the corresponding area Means for detecting the head and the headrest from the identified image area, and the head and the headrest based on the detected position of the head and the headrest. DOO relative position is characterized in that it comprises a control means for outputting a control signal for controlling the position of the headrest so as to have a predetermined positional relationship.

  A headrest control device according to a third aspect of the present invention includes a determination unit that determines whether or not the detected head position is within a predetermined adjustable range in which the position of the headrest can be adjusted. When it is determined that the determination means is within the adjustable range, a means for outputting a control signal for controlling the position of the headrest, and when the determination means is determined to be outside the adjustable range, the control signal is output. Means for stopping the operation.

  A headrest device according to a fourth aspect of the present invention is a headrest device that includes a headrest that suppresses backward tilting of the head of an occupant seated in a vehicle seat, and is configured to control the position of the headrest. Infrared imaging device, means for detecting position of occupant's head based on far-infrared image obtained by imaging by far-infrared imaging device, means for detecting position of said headrest, and detected head And a control means for controlling the position of the headrest so that the relative position of the head and the headrest is in a predetermined positional relationship based on the position of the headrest and the headrest.

  A headrest control method according to a fifth aspect of the present invention is a headrest control method for controlling the position of a headrest that suppresses rearward tilting of the head of an occupant seated in a vehicle seat. Based on the obtained far-infrared image, the step of detecting the position of the head of the occupant, the step of detecting the position of the headrest, the head and the position of the headrest based on the detected head and the position of the headrest And controlling the position of the headrest so that the relative position of the headrest is in a predetermined positional relationship.

In the first, fourth and fifth inventions, the far-infrared imaging device images the occupant and detects the position of the head based on the far-infrared image obtained by imaging. By imaging the occupant with far-infrared rays, it is possible to obtain a clear image of the occupant's head day and night and without being affected by ambient light, and to accurately detect the position of the head. Can do.
And the information which shows the position of a headrest is acquired, and the position of a headrest is detected. This is because the headrest does not emit far infrared rays sufficiently, and the position of the headrest cannot be detected from the far infrared image.
Next, the position of the headrest is controlled such that the detected relative position between the head and the headrest is a predetermined positional relationship, that is, a positional relationship that can prevent the head from tilting backward. Through the above processing, it is possible to control the position of the headrest regardless of whether it is daytime or nighttime, and is not affected by ambient light.
The far-infrared imaging device in the headrest control device according to the present invention is not an indispensable constituent element. The headrest control device includes a headrest control device including the far-infrared imaging device and a headrest control device not including the far-infrared imaging device. And are included.

In the second invention, the plurality of far-infrared imaging devices image the occupant's head. By imaging the occupant with a plurality of far-infrared imaging devices, the position of the head and the headrest in real space can be detected. In addition, by imaging the occupant with far-infrared rays, a clear image of the occupant's head can be obtained regardless of day or night, and without being affected by ambient light, and the position of the head can be accurately detected. can do.
Next, an edge is extracted from one far-infrared image. Although simple threshold processing may not be able to detect a low-temperature headrest, it is possible to detect the contour of the headrest by extracting an edge. However, the extracted edge is a state in which the edge of the head and the edge of the headrest are mixed.
Therefore, an image region including an edge group composed of a plurality of connected edge points is divided into a plurality of small regions, a corresponding region corresponding to each small region is identified from the other far-infrared image, and the small region and the corresponding region An image region having substantially the same parallax is identified. The identified image region is considered as a candidate for the head and the headrest, and the head and the headrest can be detected from the identified image region.
Next, the position of the headrest is controlled such that the detected relative position between the head and the headrest is a predetermined positional relationship, that is, a positional relationship that can prevent the head from tilting backward. Through the above processing, it is possible to control the position of the headrest regardless of whether it is daytime or nighttime, and is not affected by ambient light.

  In the third invention, it is determined whether or not the position of the head is within a predetermined adjustable range in which the position of the headrest can be adjusted. If the headrest moves forcibly when the head is not within the adjustable range, there is a risk of promoting whiplash injury. Therefore, the control means moves the headrest when it is determined that the head is located within the adjustable range, and stops the movement of the headrest when it is determined that the head is not within the position adjustment range. Therefore, useless operation of the headrest can be omitted.

  According to the present invention, the position of the headrest can be controlled regardless of daytime or nighttime by detecting the head position of the occupant with the far-infrared imaging device and detecting the position of the head. It can be carried out.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is an explanatory diagram conceptually showing a headrest device according to Embodiment 1 of the present invention, and FIG. 2 is a block diagram showing a configuration of the headrest device. The headrest device according to the first embodiment of the present invention detects the position of the head B of the occupant A by far-infrared rays, so that the position of the headrest 21 is not affected by disturbance light regardless of day or night. It is possible to perform control. The headrest device includes a headrest 21 that suppresses backward tilting of the head B at the time of a rear collision, a forward / backward movement drive unit 22 and a vertical movement drive unit 23 that move the headrest 21, and a headrest position detection unit that detects the position of the headrest 21. 5 and a headrest control device 1 that controls the operation of each component.

  The headrest 21 has a pillow shape and is composed of a headrest front half 21b and a headrest rear half 21a that can be separated and moved. A pair of connecting legs 24 projecting downward are provided in the lower part of the headrest rear body 21a, and the connecting legs 24 are inserted into the upper end portion of the backrest portion of the vehicle seat 25 so as to be able to advance and retract. The headrest 21 includes a link mechanism that connects the headrest rear half 21a and the headrest front half 21b and moves the headrest front half 21b in the front-rear direction with respect to the headrest rear half 21a. The front-rear direction means the front and rear of the vehicle.

The forward / backward drive unit 22 includes a motor (not shown) that drives the link mechanism, a motor drive circuit, and the like, and moves the headrest front half body 21b in the front-rear direction by the rotational force of the motor.
The vertical movement drive unit 23 includes a gear mechanism, a motor, a motor drive circuit, and the like that move the connecting leg 24 in the vertical direction, and moves the headrest 21 in the vertical direction by the rotational force of the motor.

FIG. 3 is an explanatory diagram conceptually showing the moving state of the headrest 21. FIG. 3A shows a state in which the headrest 21 has moved up and down as indicated by the white arrow. The headrest 21 in the initial position is indicated by a two-dot chain line. When the vertical movement drive unit 23 is driven, the headrest 21 moves upward together with the connecting leg 24. The headrest 21 moved upward from the initial position is indicated by a solid line.
FIG. 3B shows a state in which the headrest 21 has moved back and forth. The headrest 21 in the initial position, in particular, the headrest front half body 21b is indicated by a two-dot chain line. When the front-rear drive unit 22 is driven, the headrest front half body 21b moves forward as indicated by a white arrow. The headrest front half 21b moved forward from the initial position is shown by a solid line.

  The headrest control device 1 includes a control device 11 and a far-infrared imaging device 12 that image the occupant A seated on the vehicle seat 25.

  FIG. 4 is a block diagram illustrating a configuration of the far infrared imaging device 12. The far-infrared imaging device 12 is installed at an appropriate location in the passenger compartment, and is fixed in a posture capable of imaging the occupant A from the side.

  The far-infrared imaging device 12 includes an imaging unit 12a, a signal processing unit 12b, an image memory 12c for temporary storage, and a video output unit 12d, and each component is connected by a wiring 12e.

  The imaging unit 12a includes a far infrared transmissive lens. On the back side of the lens, a far-infrared imaging device that images the occupant A with far-infrared light having a wavelength of 7 to 14 μm, that is, photoelectrically converts an image formed by the lens into a luminance signal, such as a thermopile, pyroelectric device, bolometer Are arranged in a matrix. The imaging unit 12a performs imaging processing continuously or intermittently, for example, generates 30 pieces of image data (image frames) per second and outputs the image data to the signal processing unit 12b.

  The signal processing unit 12b AD converts the luminance signal into digital image data. Then, the signal processing unit 12b performs various correction processes on the AD-converted image data, and transmits the image data to the control device 11 through a cable connected to the video output unit 12d.

  Note that each pixel constituting the image is two-dimensionally arranged, and the image data is data indicating the position of each pixel indicated by a plane rectangular coordinate system and the luminance of each pixel indicated as a gradation value ( Brightness value).

  FIG. 5 is a block diagram illustrating a configuration of the control device 11. The control device 11 includes a CPU 11a, an image memory 11b, a RAM 11c, a video input unit 11d, and a communication interface unit 11e.

  The far-infrared imaging device 12 is connected to the video input unit 11d via a cable, and the image data transmitted from the far-infrared imaging device 12 is input. The image data input to the video input unit 11d is sequentially stored in the image memory 11b in units of one frame.

  The communication interface unit 11e is connected to the longitudinal drive unit 22, the vertical drive unit 23, the headrest position detection unit 5, and the rear collision determination unit 3.

  The headrest position detection unit 5 detects the position of the headrest 21, and gives information indicating the position of the headrest 21 to the CPU 11a. For example, the headrest position detection unit 5 detects a position of the vehicle seat 25, a sensor that detects the position of the headrest rear body 21a with respect to the vehicle seat 25, and a position of the headrest front body 21b with respect to the headrest rear body 21a. And a position of the headrest 21, particularly the headrest front half 21b, based on the detection result of each sensor.

The rear collision determination unit 3 is connected to a millimeter wave radar 4 that detects the position and relative speed of the rear vehicle. The rear collision determination unit 3 determines the position and relative speed of the rear vehicle detected by the millimeter wave radar 4. Based on this, it is determined whether there is a possibility of rear collision. The rear collision determination unit 3 outputs a rear collision signal to the control device 11 when determining that there is a possibility of a rear collision.
Although the millimeter wave radar 4 is illustrated as an apparatus for detecting the position and relative speed of the rear vehicle, a laser radar, an ultrasonic sensor, a visible camera, an infrared camera, or the like may be used instead of the millimeter wave radar 4.

  6 and 7 are flowcharts showing a processing procedure of the CPU 11a related to driving of the headrest 21. FIG. The CPU 11a always acquires the image data transmitted from the far-infrared imaging device 12 regardless of the reception of the collision signal, and writes the acquired image data to the image memory 11b to constantly update the content of the image data. is doing. When the rear collision determination unit 3 receives a rear collision signal indicating that there is a possibility of a rear collision, the CPU 11a reads image data from the image memory 11b (step S11).

  FIG. 8 is an explanatory diagram conceptually showing a far-infrared image. The X axis indicates the horizontal direction of the far infrared image, and the Y axis indicates the vertical direction of the far infrared image. A circular portion with hatching is an image of the head B, and a substantially rectangular portion indicated by a one-dot chain line indicates the headrest 21. Since the temperature of the head B is higher than the ambient temperature, when the occupant A is seated on the vehicle seat 25, the head B is clearly imaged. However, since the temperature of the headrest 21 is substantially the same as the ambient temperature, the headrest 21 is not clearly imaged.

  Next, the CPU 11a calculates the coordinates of the head B position in the far-infrared image based on the read image data (step S12).

  FIG. 9 is an explanatory diagram conceptually showing the positions of the head B and the headrest 21 in the far-infrared image, and FIG. 10 is an explanatory diagram conceptually showing the moving state of the headrest. 9A shows the coordinates of the position of the head B and the position of the headrest 21 in the X-axis direction, that is, the longitudinal direction of the vehicle, and FIG. 9B shows the head in the Y-axis direction, that is, the vertical direction of the vehicle. The coordinates of the part B position and the headrest position are shown. The CPU 11a extracts the image region of the head B by threshold processing, for example, and calculates the coordinate x1 of the right end of the head B in the X-axis direction, that is, the rear end position of the head B by projection calculation. Further, the CPU 11a calculates the coordinate y1 of the upper end position of the head B in the Y-axis direction by a projection calculation.

  Next, the CPU 11a acquires the position information of the headrest 21 (step S13), and calculates the coordinates of the position of the headrest 21 in the far-infrared image (step S14). As shown in FIG. 9, for example, the CPU 11 a calculates the coordinate x2 of the position of the headrest 21 in the far-infrared image, particularly the left end of the headrest 21 in the X-axis direction, that is, the position of the front end of the headrest 21. Further, the CPU 11a calculates the coordinate y2 of the upper end position of the headrest 21.

  Next, the CPU 11a determines whether or not the calculated head B is within the adjustable range of the headrest 21 (step S15). The CPU 11a stores information for determining whether or not it is within the adjustable range. When it is determined that it is outside the adjustable range (step S15: NO), the CPU 11a stops the output of the drive control signal, and stops the movement of the headrest 21 by the forward / backward drive unit 22 and the vertical drive unit 23 (step). S16), the process ends.

  When it is determined that it is within the adjustable range (step S15: YES), the CPU 11a has the relative distance Δx = | x1-x2 | between the head B and the headrest 21 in the X-axis direction, that is, the front-rear direction, within a predetermined threshold range. It is determined whether or not (step S17). When it is determined that it is outside the predetermined threshold range (step S17: NO), the CPU 11a drives the front / rear drive unit 22 by outputting a drive control signal to the front / rear drive unit 22 to move the headrest 21 forward. (Step S18).

  When it determines with it being in a predetermined threshold range (step S17: YES), CPU11a stops operation | movement of the back-and-forth movement drive part 22 (step S19).

  When the processing of step S18 or step S19 is completed, the CPU 11a determines whether or not the relative distance Δy = | y1-y2 | between the head B and the headrest 21 in the Y-axis direction, that is, the vertical direction is within a predetermined threshold range. Is determined (step S20). When it determines with it being in the predetermined threshold range (step S20: YES), CPU11a stops operation | movement of the vertical motion drive part 23 (step S21), and complete | finishes a process.

  If it is determined that | y1-y2 | is not within the predetermined threshold range (step S20: NO), the CPU 11a determines whether (y1-y2) is equal to or greater than the predetermined threshold (step S22). When it is determined that (y1-y2) is equal to or greater than the threshold (step S22: YES), the CPU 11a outputs a drive control signal to the vertical movement drive unit 23, as shown in FIG. 9B. Then, the vertical movement drive mechanism is driven, the headrest 21 is moved upward (step S23), and the process ends. When it is determined that (y1-y2) is not equal to or greater than the threshold (step S22: NO), the CPU 11a drives the vertical movement drive unit 23 by outputting a drive control signal to the vertical movement drive unit 23, and the headrest 21 Is moved downward (step S24), and the process ends.

  By the above-described processing, the headrest front half 21b moves to the rear side of the head B as shown in FIG. 10, and can effectively suppress the backward tilting of the head B at the time of collision.

  In this Embodiment 1, since it is the structure which images the passenger | crew A with the far-infrared imaging device 12, and detects the position of the head B, it is not influenced by disturbance light regardless of day and night. The position control of the headrest 21 can be performed.

  In addition, when the head B is not located within the adjustable range, the operation of the headrest 21 is prohibited, so that useless operation of the headrest 21 can be omitted.

  In the first embodiment, the headrest control device is configured by the far infrared imaging device and the control device. However, the far infrared imaging device may be configured to incorporate the control device.

  Moreover, although it has comprised so that a passenger | crew may be imaged from a side surface, the attachment attitude | position of a far-infrared imaging device is not limited to this. For example, you may comprise so that a passenger | crew may be imaged from the ceiling side of a vehicle.

(Embodiment 2)
FIG. 11 is an explanatory diagram conceptually showing the headrest device according to the second embodiment of the present invention. As with the headrest device according to the first embodiment, the headrest device according to the second embodiment of the present invention includes the headrest control device 1, the headrest 21, the longitudinal drive unit 22, the vertical drive unit 23, the rear collision determination unit 3, and A millimeter wave radar 4 is provided. The headrest device according to the second embodiment differs from the headrest device according to the first embodiment in that the headrest device is configured to detect the position of the headrest 21 based on the far-infrared image. Will be explained.

The headrest device according to the second embodiment includes heating elements 26 and 27 provided at appropriate portions of the headrest front half 21b, for example, the upper end portion and the front surface portion.
The far-infrared imaging device 12 is fixed in a posture capable of imaging the heating elements 26 and 27 provided on the head B of the occupant A seated on the vehicle seat 25 and the headrest front half 21b.

  FIG. 12 is an explanatory diagram conceptually showing a far-infrared image obtained by imaging the head B and the heating elements 26 and 27. A circular portion with hatching is an image of the head B, and a black circle portion is an image of the heating elements 26 and 27. Since the temperature of the head B and the heating elements 26 and 27 is higher than the ambient temperature, when the occupant A is seated on the vehicle seat 25, the head B and the heating elements 26 and 27 are clearly imaged.

  When the CPU 11a receives a rear collision signal, the CPU 11a acquires a far-infrared image, and extracts the head B and the heating elements 26 and 27 by binarizing the acquired far-infrared image. Then, the CPU 11a detects the position of the head B by projection calculation. In addition, the CPU 11a specifies the position of the headrest front half 21b based on the positions of the heating elements 26 and 27. Hereinafter, the position control of the headrest 21 is performed by executing the same processing as the processing of steps S15 to S24 shown in FIG.

  In the second embodiment, it is not necessary to detect information indicating the position of the headrest 21 by an external sensor, the positions of the head B and the headrest 21 are calculated from the far-infrared image, and the position control of the headrest 21 is performed. It can be performed.

  In the second embodiment, dot-like heating elements are provided on the upper end portion and the front surface portion of the headrest front half. However, if the position of the headrest can be detected, the arrangement, shape, and number of heating elements are determined. Is not limited to this.

  The other configurations, operations, and effects of the headrest device, the headrest control device 1, and the headrest control method according to the second embodiment are the same as the configuration of the headrest device according to the first embodiment. The same reference numerals are assigned and detailed description thereof is omitted.

(Embodiment 3)
FIG. 13 is an explanatory diagram conceptually showing the headrest device according to the third embodiment of the present invention, and FIG. 14 is a block diagram showing the configuration of the headrest device according to the third embodiment. As with the headrest device according to the first embodiment, the headrest device according to the third embodiment of the present invention includes a headrest control device 301, a headrest 21, a longitudinal drive unit 22, a vertical drive unit 23, a rear collision determination unit 3, and A millimeter wave radar 4 is provided. The headrest device according to the third embodiment is configured to detect the positions of the head B and the headrest 21 based on a plurality of far-infrared images picked up by stereo vision according to the first embodiment. Since it is different from the headrest device, the difference will be mainly described below.

The headrest device according to the third embodiment of the present invention includes two far-infrared imaging devices 312a and 312b for detecting the positions of the head B and the headrest 21 based on the principle of triangulation. The far-infrared imaging devices 312a and 312b are fixed in a posture capable of imaging the head B and the headrest 21 of the occupant A seated on the vehicle seat 25 from the front side.
When receiving the rear collision signal, the CPU 11a acquires the far infrared images obtained by the far infrared imaging devices 312a and 312b and detects the head B and the headrest 21 from the far infrared images. Hereinafter, a method for detecting the head B and the headrest 21 will be described.

  FIG. 15 is a flowchart showing details of the processing procedure of the CPU 11a related to object detection, and FIGS. 16 and 17 are explanatory diagrams conceptually showing a method of detecting an object. The CPU 11a performs edge extraction processing on the far-infrared image (hereinafter referred to as a reference image) acquired from one far-infrared imaging device 312a (step S31). Specifically, the CPU 11a extracts an edge by filter processing and threshold processing by an edge extraction operator. The edge extraction operator is preferably a Pruit wit operator that extracts vertical edges.

  FIG. 16A is an explanatory diagram conceptually showing an edge image obtained by the edge extraction process. X indicates the horizontal direction of the far infrared image, and Y indicates the vertical direction of the far infrared image. The edge image is a binary image, and each pixel constituting the edge image has a value of 1 at a portion having an edge and 0 at a portion having no edge. Hereinafter, a pixel having a value of 1 in the edge image is referred to as an edge point.

Next, the CPU 11a specifies an edge group composed of a plurality of adjacent edge points, for example, a plurality of edge points connected by 8 (step S32). At this stage, the edge of the head B and the edge of the headrest 21 are mixed and specified as one edge group. Hereinafter, the process which discriminate | determines the head B and the headrest 21 is performed.
Then, the CPU 11a sets a rectangular area circumscribing the edge group, and divides the set rectangular area into blocks of a predetermined size (for example, 4 × 4 pixels) (step S33). The block size is an example and is not limited to 4 × 4 pixels.

  FIG. 16B is an explanatory diagram conceptually showing an edge image divided into blocks. The edge group is divided into 8 × 7 = 56 blocks. For convenience of drawing and explanation, the block size is drawn large.

  And CPU11a specifies the block containing an edge as an edge area | region (step S34). Next, the CPU 11a specifies a corresponding region corresponding to the edge region in the far-infrared image captured by the other far-infrared imaging device 312b so as to calculate the distance to each edge region by triangulation (step S35). ). Hereinafter, a far infrared image captured by the far infrared imaging device 312b is referred to as a reference image.

  Specifically, the CPU 11a sets a region (reference region) having the same size as the edge region in the reference region, particularly a point on the epipolar line indicated by a one-dot chain line, and calculates a correlation value R between the reference region and the reference region. . Further, the CPU 11a performs the same process for each other point on the epipolar line, and specifies the point on the epipolar line where the correlation value R is maximized as the position of the corresponding region. The correlation value R is calculated based on Equation 1, for example.

Here, N is the total number of pixels in the edge region and the reference region, k is an integer from 0 to N−1, F _k is the pixel value of the k th pixel in the edge region, and G _k is the k th pixel in the reference region. The pixel value of the pixel, R represents the correlation value. Note that the correlation value calculation method is not limited to this, and other methods such as an absolute difference sum method, a normalized cross-correlation method, and the like may be used.

  Next, the CPU 11a calculates the parallax between each edge region and the corresponding region (step S36). The parallax can be calculated based on the coordinates of the edge region or the corresponding region in the far-infrared image.

Next, the CPU 11a compares the parallax difference of each edge area with a first threshold, for example 2, and re-specifies a new edge group by grouping edge areas where the parallax difference is smaller than the first threshold. (Step S37). By the process of step S37, the edge group consisting of the edge of the head B and the edge group consisting of the edge of the headrest 21 are discriminated and re-specified.
Then, the CPU 11a detects the head B and the headrest 21 by calculating the feature amount such as the aspect ratio and the correlation with the predetermined shape from the re-specified image area (step S38), and the process related to the object detection Finish.

  FIG. 17 is an explanatory diagram conceptually showing the re-specified edge group. The small areas with hatching are edge areas including edges, and the small areas with hatching in different oblique directions belong to different edge groups. By the process of step S37, the edge part of the head B having different parallax and the edge part of the headrest 21 are re-specified as different edge groups.

The CPU 11a can calculate the position of the head B in the real space by calculating the average value of the parallax of the identified edge region of the head B. Similarly, by calculating the average value of the parallax of the edge region of the headrest 21, the coordinates of the position of the headrest 21 in the real space can be calculated.
Hereinafter, the position control of the headrest 21 is performed by executing the same processing as the processing of steps S15 to S24 shown in FIG.

  In the third embodiment, it is not necessary to provide a heating element in the headrest 21 as in the second embodiment, and the positions of the headrest 21 and the head B are directly detected from the far-infrared image, and the headrest 21 Position control can be performed.

  Other configurations, operations, and effects of the headrest device, the headrest control device, and the headrest control method according to the third embodiment are the same as the configuration of the headrest device and the like according to the first embodiment. The detailed description is abbreviate | omitted.

  It should be understood that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is explanatory drawing which shows notionally the headrest apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of a headrest apparatus. It is explanatory drawing which shows notionally the movement state of a headrest. It is a block diagram which shows the structure of a far-infrared imaging device. It is a block diagram which shows the structure of a control apparatus. It is a flowchart which shows the process sequence of CPU which concerns on the drive of a headrest. It is a flowchart which shows the process sequence of CPU which concerns on the drive of a headrest. It is explanatory drawing which shows a far-infrared image notionally. It is explanatory drawing which shows notionally the position of the head and headrest in a far-infrared image. It is explanatory drawing which shows notionally the movement state of a headrest. It is explanatory drawing which shows notionally the headrest apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows notionally the far-infrared image obtained by imaging a head and a heat generating body. It is explanatory drawing which shows notionally the headrest apparatus which concerns on Embodiment 3 of this invention. FIG. 10 is a block diagram illustrating a configuration of a headrest device according to a third embodiment. It is a flowchart which shows the detail of the process sequence of CPU concerning an object detection. It is explanatory drawing which shows the detection method of an object notionally. It is explanatory drawing which shows the detection method of an object notionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,301 Headrest control apparatus 3 Rear collision judgment part 4 Millimeter wave radar 5 Headrest position detection part 11 Control apparatus 11a CPU
12, 312a, 312b Far-infrared imaging device 21 Headrest 21a Headrest latter half body 21b Headrest front half body 22 Longitudinal movement drive section 23 Vertical movement drive section 24 Connecting leg 25 Vehicle seat A Crew B Head

Claims (5)

In the headrest control device for controlling the position of the headrest that suppresses the backward tilt of the head of the occupant seated on the vehicle seat,
Means for detecting the position of the head of the occupant based on the far-infrared image obtained by imaging by the far-infrared imaging device;
Means for acquiring position information indicating the position of the headrest;
Based on the detected position of the head and the position of the headrest indicated by the acquired position information, a control signal for controlling the position of the headrest is output so that the relative position of the head and the headrest is in a predetermined positional relationship. And a headrest control device. In the headrest control device for controlling the position of the headrest that suppresses the backward tilt of the head of the occupant seated on the vehicle seat,
Means for extracting an edge point from a far-infrared image obtained by imaging by one far-infrared imaging device;
Means for identifying an edge group comprising a plurality of connected edge points;
Means for dividing an image region including the identified edge group into a plurality of small regions;
Means for identifying a corresponding region corresponding to a divided small region including an edge point from a far-infrared image obtained by imaging by another far-infrared imaging device;
Means for identifying an image area in which the parallax of the small area and the corresponding area are substantially equal;
Means for detecting the head and the headrest from the identified image region;
Control means for outputting a control signal for controlling the position of the headrest so that the relative position of the head and the headrest is in a predetermined positional relationship based on the detected position of the head and the headrest. A headrest control device. A determination unit that determines whether or not the position of the detected head is within a predetermined adjustable range in which the position of the headrest can be adjusted;
The control means includes
Means for outputting a control signal for controlling the position of the headrest when the determination means determines that the adjustment means is within the adjustable range;
The headrest control device according to claim 1, further comprising: a unit that stops outputting the control signal when the determination unit determines that the control unit is outside the adjustable range. In a headrest device comprising a headrest that suppresses backward tilting of the head of an occupant seated in a vehicle seat and configured to control the position of the headrest.
A far-infrared imaging device for imaging an occupant;
Means for detecting the position of the head of the occupant based on the far-infrared image obtained by imaging by the far-infrared imaging device;
Means for detecting the position of the headrest;
And a control means for controlling the position of the headrest so that the relative position of the head and the headrest is in a predetermined positional relationship based on the detected position of the head and the headrest. . In a headrest control method for controlling the position of a headrest that suppresses backward tilting of the head of an occupant seated in a vehicle seat,
Imaging the occupant with far infrared,
Detecting the position of the head of the occupant based on the far-infrared image obtained by imaging;
Detecting the position of the headrest;
Controlling the position of the headrest based on the detected position of the head and the headrest so that the relative position of the head and the headrest is in a predetermined positional relationship. .

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