JP2009145176A - System, apparatus, method and program for detecting head position - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system, an apparatus, a method and a program, for detecting a head position, widening a detectable range of the head position of an occupant and detecting the head position precisely. <P>SOLUTION: The position detecting system 2 which detects the head position of a driver, comprises: four distance measuring sensors 6 which are arranged such that portions of their detection ranges are overlapped mutually, and measure distances from the head of the sitting driver; and a position detecting device 5 which selects three measurement distances among distances measured by respective distance measuring sensors 6 and calculates the head position of the driver, based on the selected measurement distances. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a head position detection system, a head position detection device, a head position detection method, and a head position detection program.

  Current automobile safety technologies include, for example, preventive safety technologies to avoid accidents, such as a driving assistance system that captures the blind spots of drivers with an in-vehicle camera and displays the images, and protects passengers in the event of an accident. Can be classified as occupant protection safety technology. In order for these safety techniques to work with accuracy, it is necessary to accurately grasp the head position of the occupant.

For example, Patent Document 1 describes a device that detects an occupant's sitting height using an ultrasonic sensor provided on a roof surface and deploys an airbag at a position where the occupant's cervical vertebra is estimated to be present. Moreover, this apparatus measures the distance from a headrest to a passenger | crew's head with the ultrasonic sensor provided in the headrest, and sets the expansion | deployment intensity | strength of an airbag according to distance.
JP-A-11-334516

  In the apparatus described in the above document, the seat height of the occupant is calculated by subtracting the distance from the head measured by the ultrasonic sensor from the fixed distance between the sensor and the seating surface of the occupant. Further, a predetermined position of the sitting height is determined as the position of the cervical vertebra, and the position is set as a position for deploying the airbag. However, in the case of this method, when the occupant's posture is tilted to the left or right and the head is biased to the left or right, the position of the head such as the left or right position of the head It is difficult to determine the dimensional coordinates.

  The present invention has been made in view of the above problems, and an object of the present invention is to enlarge the range in which the occupant's head position can be detected and to detect the head position with high accuracy. Another object is to provide a head position detection device, a head position detection method, and a head position detection program.

  In order to solve the above-described problems, the invention according to claim 1 is a head position detection system for detecting the position of the head of an occupant, and is disposed and seated so that parts of the detection range overlap each other. At least four ranging sensors for measuring the distance to the occupant's head and an area where the occupant's head is located are estimated, and among the measurement distances measured by the respective ranging sensors, three of the measuring distances close to the area are measured. The gist of the invention is that it comprises selection means for selecting a measurement distance measured by a distance sensor, and position calculation means for calculating the head position of the occupant based on the selected measurement distance.

  According to a second aspect of the present invention, in the head position detection system according to the first aspect, the selecting means includes the three measurement distances from the shortest distance among the measurement distances measured by the distance measuring sensors. The gist is to select the measurement distance measured by the distance sensor.

  According to a third aspect of the present invention, in the head position detection system according to the first aspect of the present invention, the head position detection system includes pressure detection means for detecting pressure applied to the seat by the load of the occupant, and the selection means includes the pressure bias. The gist is to select the measurement distance measured by the three distance measuring sensors close to the direction.

  According to a fourth aspect of the present invention, in the head position detection system according to the first aspect of the present invention, the head position detection system further includes direction detection means for detecting a traveling direction of the vehicle, and the selection means is the vehicle detected by the direction detection means. Based on the traveling direction of the vehicle, the region where the occupant's head is associated with the traveling direction is estimated, and the measurement distance measured by the three distance measuring sensors close to the region is selected.

  According to a fifth aspect of the present invention, in the head position detection system according to the first aspect of the present invention, image data is acquired from an imaging device that captures an area including the head of the occupant seated on the seat, and the image data is acquired. The image processing means further comprises an image processing means for performing image processing to estimate an area where the occupant's head is located, and the selection means selects measurement distances measured by the three distance measuring sensors close to the area where the occupant's head is located. The gist is to do.

  According to a sixth aspect of the present invention, in the head position detection system according to any one of the first to fifth aspects, the position calculating means sets a predicted position of the occupant's head, and the predicted position And correcting the predicted position based on the measured distance measured by the selected distance measuring sensor and the positions of the three distance measuring sensors that have measured the measured distance, and the corrected predicted position is The gist is to specify the head position of the passenger.

  According to a seventh aspect of the present invention, in the head position detecting device for detecting the position of the head of the occupant, a part of the detection range is arranged so as to overlap each other, and the distance to the head of the seated occupant is measured. An acquisition means for acquiring measurement distances from at least four distance sensors, and an area where the occupant's head is located, and the measurement distances measured by the three distance sensors near the area among the measurement distances And a position calculation means for calculating the head position of the occupant based on the selected measurement distance.

  The invention according to claim 8 is a head position detection method for detecting the position of an occupant's head using a distance measuring sensor. The head of the seated occupant is arranged such that parts of the detection range overlap each other. Each of the distance measurement sensors obtains measurement distances from at least four distance measurement sensors that measure the distance to the unit, estimates a region where the occupant's head is located, and the three distance measurement sensors near the region among the measurement distances The gist is to select the measured measurement distance and calculate the head position of the occupant based on the selected measurement distance.

  According to a ninth aspect of the present invention, in the head position detection program for detecting the position of the head of the occupant using the distance measuring sensor and the control means, the control means is partially overlapped with the detection range. An acquisition means for acquiring measurement distances from at least four distance measuring sensors for measuring the distance to the head of the seated occupant, and estimating the area where the occupant's head is located, Of these, the selection means for selecting the measurement distances measured by the three distance measuring sensors close to the area and the position calculation means for calculating the head position of the occupant based on the selected measurement distances are summarized. And

  According to the first aspect of the present invention, the head position detection system includes three distance measuring sensors that are close to an area where it is estimated that the head is present, among the measured distances measured by at least four distance measuring sensors. Select the measured distance. For this reason, the region where the head position can be specified can be widened, and the head position can be detected with high accuracy.

According to the invention described in claim 2, by selecting three measurement distances from the shorter one among the measurement distances measured by the respective distance measuring sensors, an optimum measurement distance can be selected, and a measurement value with a small error. Since the head position can be calculated using, the head position detection accuracy can be improved. Further, regardless of the number of distance measuring sensors, three measuring distances can be selected by a simple method.

  According to the third aspect of the present invention, the measurement distances measured by the three distance measuring sensors that are close to the direction in which the pressure is biased by the passenger's load is selected. For this reason, since the optimal measurement distance can be selected and the head position can be calculated using the measurement value with a small error, the detection accuracy of the head position can be improved.

  In the fourth aspect of the present invention, a region associated with the traveling direction of the vehicle is estimated, and a measurement distance measured by three distance measuring sensors close to the region is selected. For this reason, it is possible to easily select an optimum measurement distance among the measurement distances measured by the respective distance measuring sensors.

  According to the fifth aspect of the present invention, image data obtained by photographing the head of the occupant is subjected to image processing, a region where the head is located is estimated, and a measurement distance measured by a distance measuring sensor close to the region is selected. For this reason, it is possible to easily select an optimum measurement distance among the measurement distances measured by the respective distance measuring sensors.

  According to the invention described in claim 6, the predicted position of the head is set, and the predicted position is determined based on the predicted position, the measured distance measured by the selected distance measuring sensor, and the positions of the three distance measuring sensors. Make corrections. Therefore, the head position can be calculated using only the position of the distance measuring sensor and the measurement distance without using a special device such as a sensor capable of calculating a relative angle with the head position.

  According to the seventh aspect of the present invention, the head position detecting device includes three distance measuring sensors that are close to an area estimated to have the head among the measured distances measured by at least four distance measuring sensors. Select the measured distance. For this reason, the region where the head position can be specified can be widened, and the head position can be detected with high accuracy.

  According to the method of claim 8, among the measurement distances measured by at least four distance sensors, the measurement distances measured by the three distance sensors close to the region estimated to have the head are selected. . For this reason, the region where the head position can be specified can be widened, and the head position can be detected with high accuracy.

  According to the ninth aspect of the invention, in accordance with the head position detection program, among the distances measured by at least four distance measuring sensors, three distance measuring sensors that are close to the region estimated to have the head are provided. Select the measured distance. For this reason, the region where the head position can be specified can be widened, and the head position can be detected with high accuracy.

(First embodiment)
Hereinafter, an embodiment of a head position detection system embodying the present invention will be described with reference to FIGS. As shown in FIG. 1, a position detection system 2 that detects the head position of a driver as an occupant constitutes a part of a driving support system 1 that assists the driver's blind spot. The driving support system 1 is a system that captures a blind spot area blocked by a pillar, which is a column supporting a window or a roof, and displays the image on the pillar. The photographed image is displayed on the inner surface of the pillar after image processing is performed in accordance with the driver's head position so as to match the driver's viewpoint.

  In addition to the position detection system 2, the driving support system 1 includes an image display system 3 that performs image processing in accordance with the head position. The position detection system 2 includes a position detection device 5 as a selection means, a position calculation means, an acquisition means, a head position detection device and a control means, and four distance measuring sensors 6 provided in the vehicle.

  The position detection device 5 includes a CPU, a RAM, a ROM (not shown), and the like, specifies the head position of the driver based on the measurement distance measured by each distance measuring sensor 6, and displays the specified head position as an image display system. 3 is output. In the present embodiment, each distance measuring sensor 6 is a sensor that irradiates a measurement target with an ultrasonic pulse and measures the distance to the measurement target.

  The distance measuring sensor 6 includes a control unit, a transmission unit that transmits ultrasonic pulses, and a reception unit (all not shown) that receives a reflected wave reflected by an object. The transmission unit includes an oscillator and a transmission element made of a piezoelectric element or the like. The control unit controls the transmission timing based on the clock signal generated by the oscillator, and drives the transmission element to transmit the outgoing wave. The transmitting element is an element having directivity for transmitting an outgoing wave in a predetermined angle range. The receiving unit includes a receiving element, an encoding unit that encodes the received reflected wave, and a memory (none of which is shown) that stores the pattern and parameters of the reflected wave.

  The control unit of the distance measuring sensor 6 measures the time from when the outgoing wave is transmitted to when the reflected wave is received based on the clock signal. Further, the relative distance to the measurement object reflected by the outgoing wave is calculated from that time.

  As shown in FIGS. 2 and 3, each distance measuring sensor 6 is attached so as to surround a movable range of the head D <b> 1 of the driver D seated on the driver's seat 101. FIG. 3 is a schematic diagram showing the mounting position of each sensor 6 as viewed from above the driver's seat 101 (Z direction). The first distance measuring sensor FR is located on the front right side of the seating position of the driver D, and is provided on the inner surface of the roof. The second distance measuring sensor RR is located on the right side or the rear right side of the seating position, and is provided on the inner surface of the roof. The third distance measuring sensor RL is located on the left side or the rear left side of the seating position, and is provided on the inner surface of the roof. The fourth distance measuring sensor FL is located on the front left side of the seating position, and is provided, for example, in the vicinity of the room mirror.

  The space surrounded by each distance measuring sensor 6 is set in advance as a detection target range Z1. The detection target range Z1 includes a range in which the head D1 can move when the driver D sits on the driver's seat 101, and is erroneously detected by a fixed object in the vehicle such as an instrument panel, a steering wheel, and the driver's seat 101. It is set in a difficult range.

  In the present embodiment, each distance measuring sensor 6 is disposed in the vicinity of four vertices on a rectangular plane that is the upper surface of the detection target range Z1. In FIG. 2, the positions of the distance measuring sensors 6 in the Z direction are the same, but the height positions may be different. In FIG. 3, the distance between the distance measuring sensors 6 is the same, but may be different.

  As shown in FIG. 2, the length in the Z direction of the detection target range Z1 is, for example, a range in which the head D1 of the driver D who is driving can move, and other parts such as legs of the driver D, driving A fixed object such as a seat cushion of the seat 101 is set in a range in which it is difficult to detect erroneously. Each distance measuring sensor 6 provided at the corner of the detection target range Z1 irradiates an outgoing wave toward the inside of the detection target range Z1. The outgoing wave is reflected by the head D1, and the reflected wave is received by each distance measuring sensor 6. At this time, when a part of a fixed object such as a handle is included in the detection target range Z1, the time or the pattern of the reflected wave is measured from when the outgoing wave is transmitted until the reflected wave of the fixed object is received. Measurement is performed in advance, and at the actual measurement, the measurement result of the reflected wave of the fixed object is excluded based on the time or pattern.

As shown in FIG. 4A, each detection range Z2 of the distance measuring sensor 6 has a radial shape with the sensor position as the apex, and the range covers a wide range of the detection target range Z1 while maintaining the detection accuracy. It is adjusted to cover. That is, the detection range Z2 is adjusted to almost the entire area except for a part of the detection target range Z1. Further, since the detection range Z2 is adjusted to cover the wide range of the detection target range Z1 under the restriction of the shape of the detection range Z2, a part of the detection range Z2 slightly protrudes from the detection target range Z1.

  In the process of specifying the head position, the position detection device 5 estimates the area where the head D1 is located among the measurement distances measured by the four distance measuring sensors 6, and the three distance measuring sensors 6 near the area. Select the measured distance measured by.

  Here, the identifiable range of the head D1 when the three distance measuring sensors 6 are selected will be described in detail. For example, as shown in FIG. 4B, when the first distance sensor FR, the third distance sensor RL, and the fourth distance sensor FL are selected from the four distance measurement sensors 6, each distance measurement is performed. A region where the detection ranges Z2 of the sensors FR, RL, and FL overlap with each other is an identifiable range Z3 in which the head position can be actually specified. When three distance measuring sensors 6 out of the four are used, almost the entire detection target range Z1 can be set to the identifiable range Z3.

  Further, the detection range Z2 of each distance measuring sensor 6 is adjusted so as not to protrude from the detection target range Z1 as much as possible. For this reason, the fall of the precision by attenuation | damping of an ultrasonic wave and the erroneous detections, such as a reflected wave reflected on fixed objects, such as an instrument panel outside the detection target range Z1, can be suppressed. That is, by selecting the measurement distances measured by the three distance measuring sensors 6 among the four distance measuring sensors 6, the target range in which the head D1 can be detected can be widened while maintaining high accuracy. it can.

  For comparison with this selection method, when the head position is specified using all the distance measuring sensors 6, the detection range Z2 of the distance measuring sensor 6 is expanded in order to expand the identifiable range Z3, and false detection is performed. A case where the detection range Z2 is reduced to prevent this will be described.

  As shown in FIG. 5, in the case where the head position is specified using four distance measuring sensors 6 having the same detection range Z2 as in the present invention, the specified range Z3 where the detection ranges Z2 of the four distance measuring sensors 6 overlap. Is smaller than the identifiable range Z3 of the present embodiment described above. For this reason, there is a possibility that the head position cannot be specified when the driver D bends forward or when the posture is tilted left and right at the time of left turn and right turn.

  On the other hand, when the detection range Z2 of each of the three distance measuring sensors 6 is expanded as shown in FIG. 6A in order to expand the identifiable range Z3, the area that protrudes from the detection target range Z1 also increases. In this case, as shown in FIG. 6B, the identifiable range Z3 is expanded more than the identifiable range Z3 of the present embodiment, but erroneous detection is performed by expanding the region that extends from the detection target range Z1. The possibility increases and the accuracy decreases.

  In order to increase accuracy, as shown in FIG. 7A, the detection range Z2 of the distance measuring sensor 6 is adjusted so that there is no region protruding from the detection target range Z1, although erroneous detection can be suppressed, FIG. As shown in (a), the identifiable range Z3 is reduced. For this reason, there is a possibility that the head position cannot be specified when the driver D bends forward or when the posture is tilted left and right at the time of left turn and right turn.

  For this reason, in the state which adjusted the attachment position and detection range Z2 of the ranging sensor 6 according to arrangement | positioning and detection accuracy, such as an instrument panel in a vehicle, a driver's seat, etc., among the four ranging sensors 6 at the time of a measurement, By selecting the three distance measuring sensors 6, it is possible to maintain the detection accuracy and keep the identifiable range Z3 in a suitable range.

Next, processing for calculating the three-dimensional coordinates (X, Y, Z) of the head position of the position detection device 5 will be described. Here, the center of the sphere when the head D1 is approximated to a sphere is calculated as the head position. When detecting the head position, the position detection device 5 radiates outgoing waves from the distance measuring sensors 6 toward the inside of the detection target range Z1. Then, as shown in FIG. 8, each measurement distance La is calculated based on the time from when the outgoing wave is transmitted until when the reflected wave is received.

  In the present embodiment, the position detection device 5 selects three measurement distances La from the shortest distance among the measurement distances La measured by the distance measuring sensor 6. That is, when the head D1 is biased to the front left side, the measurement distance La2 measured by the second distance measuring sensor RR becomes the largest. The ultrasonic waves tend to attenuate in the air, and the detection accuracy decreases as the distance to the measurement object increases. Therefore, the measurement distance La2 having the longest distance among the four measurement distances La is excluded.

  When the three measurement distances La are selected, the position detection device 5 adds the head radius R to each measurement distance La as shown in FIG. That is, in this embodiment, the head position D2 (X, Y, Z) when the head D1 is a sphere is estimated as the head position, but the measurement distance La measured by the distance measuring sensor 6 is The distance between the distance measuring sensor 6 and the head surface. Therefore, in consideration of the average adult head size, the head radius R is added to the measurement distance La to calculate a correction distance Lb corresponding to the distance from the distance measuring sensor 6 to the head position D2. .

  Next, the position detection device 5 sets the coordinates of the initial position P1 (X1, Y1, Z1) to the predicted position Pi (Xi, Yi, Zi) for estimating the head position D2. The initial position P1 can be arbitrarily set, for example, the center coordinates of the detection target range Z1. Further, the position detection device 5 acquires a sensor position indicating the position of each distance measuring sensor 6 stored in advance, and calculates a relative distance Lc from the predicted position Pi (X1, Y1, Z1) to each distance measuring sensor 6, respectively. To do.

  Further, each relative distance Lc is compared with each of the correction distances Lb, and the adjustment for making the predicted position Pi closer to the head position D2 that is a true value is repeatedly performed. Specifically, as shown in FIG. 10, when the predicted position Pi is set as the center coordinate of the detection target range Z1, the predicted position Pi, the first distance sensor FR, the third distance sensor RL, and the fourth distance measurement are measured. A relative distance Lc from the distance sensor FL is calculated. Further, a difference between each relative distance Lc and each correction distance Lb corresponding to the relative distance Lc is set as a correction value ΔL, and it is determined whether the correction value ΔL is less than a predetermined value Ld as a predetermined distance.

  The predetermined value Ld is an arbitrary value. In the present embodiment, the predetermined value Ld is set in an allowable range as an error of the head position in the image processing for displaying the image on the inner surface of the pillar. When it is determined that the correction value ΔL is equal to or less than the predetermined value Ld, the predicted position Pi at that time is specified as the head position DH. If it is determined that the correction value ΔL is greater than the predetermined value Ld, the predicted position Pi is corrected based on the correction value ΔL so as to approach the head position D2.

  At this time, for example, the relative distances Lc and the correction distances Lb are compared to limit the region where the head position D2 exists. That is, when the head position D2 that is a true value is located on the front left side in FIG. 11 in the detection target range Z1, the first correction distance Lb1 is the first distance sensor FR from the center of the detection target range Z1. The value is slightly smaller than the first relative distance Lc1 until. For this reason, the head position D2 is estimated to be located inside the sphere S1 with the first distance sensor FR as the center and the first relative distance Lc1 as the radius. Similarly, since the third correction distance Lb3 is longer than the third relative distance Lc3, the head position D2 is outside the sphere S3 centered on the third distance measuring sensor RL and having the radius of the third relative distance Lc3. Presumed to be located. Further, since the fourth correction distance Lb4 is shorter than the fourth relative distance Lc4, it is estimated that the fourth correction distance Lb4 is located inside the sphere S4 with the fourth distance sensor L as the center and the fourth relative distance Lc4 as the radius. Thereby, it can be determined that the head position D2 is located outside the sphere S3 and in the estimated region Z4 where the sphere S1 and the sphere S4 overlap.

  When the estimated area Z4 is determined, the predicted position Pi (X2, Y2, Z2) is set at an arbitrary position such as the center coordinates of the estimated area Z4. Further, the relative distance Lc between the predicted position Pi and each of the three distance measuring sensors 6 is calculated, and the relative distance Lc and the correction distance Lb are compared to further limit the estimated region Z4. Then, the adjustment of the predicted position Pi is repeated until the correction value ΔL between the relative distance Lc and the correction distance Lb becomes equal to or less than the predetermined value Ld. The adjustment of the predicted position Pi is not limited to the above method, and other methods may be used. When the correction value ΔL between the relative distance Lc and the correction distance Lb is equal to or less than the predetermined value Ld, the position detection device 5 specifies the predicted position Pi at that time as the calculated head position DH.

  The head position DH calculated by the position detection system 2 is output to the image display system 3. The image display system 3 includes an image processing device 7 and a navigation computer 8. The navigation computer 8 calculates the vehicle position based on the vehicle speed sensor 12 and the gyro 13 and outputs the vehicle position to the image processing device 7. Further, the navigation computer 8 acquires map data 15 indicating road information, terrain information, etc. around the own vehicle position from the map data storage unit 14, and the road information or terrain information, etc. ahead of the own vehicle position is obtained from the image processing device 7. Output to.

  The image processing apparatus 7 inputs image data from a camera 10 attached to the vehicle 100 as shown in FIG. Further, in accordance with the head position DH calculated by the position detection system 2, image processing such as coordinate conversion and trimming according to the pillar shape is performed. For example, when the head position D2 is biased to the front left side in the detection target range Z1, the optical axis AX1 of the camera 10 and the line-of-sight direction AX2 of the driver D are different directions. Further, when displaying an image on the inner surface of the pillar, it is necessary to set which position on the road surface is drawn as the center. For this reason, it is necessary to calculate the line-of-sight direction AX2 when the driver D views the pillar 102 based on the head position D2, and to perform coordinate conversion of the captured image to a projection plane that matches the line-of-sight direction AX2. For example, the image processing device 7 sets a projection plane at a position that is matched with the line-of-sight direction AX2 based on the own vehicle position and map data 15 acquired from the navigation computer 8 and should be confirmed during driving, You may make it coordinate-transform image data to the projection surface. Further, the image processing device 7 performs coordinate conversion for displaying the converted data subjected to coordinate conversion on the display surface of the display device 11.

  The image processing device 7 generates display data to be displayed on the inner surface of the pillar by the above-described image processing. Then, the display data is output to the display device 11. The display device 11 is a thin liquid crystal display or the like provided on the inner surface of the pillar, and displays a blind spot image blocked by the pillar 102 based on display data input from the image processing device 7.

  Next, the procedure of the head position detection process according to the present embodiment will be described with reference to FIGS. The position detection device 5 determines whether or not to start detecting the head position (step S1). Specifically, it is determined whether a detection start command output from the image display system 3 in the image display mode has been received. If a detection start command is received, it is determined to start detecting the head position (YES in step S1). If a detection start command is not received (NO in step S1), the process waits until a start trigger is input.

When receiving the detection start command, the position detection device 5 drives each distance measuring sensor 6 and acquires the measurement distance La from each distance measuring sensor 6 (step S2).
Further, the position detection device 5 performs a selection process of selecting three measurement distances La among the measurement distances La measured by the four distance measurement sensors 6 in accordance with preset conditions (step S3). In the present embodiment, as described above, three measurement distances La are selected from the shorter distance.

When the three measurement distances La are selected, the position detection device 5 performs the above-described position calculation process based on the selected three measurement distances La (step S4). Specifically, as shown in FIG. 14, the initial position P1 is set to the predicted position Pi (step S4-1). Further, a relative distance Lc between the predicted position Pi and each corresponding distance measuring sensor 6 is calculated (step S4-2). Further, the relative value Lc and each correction distance Lb are compared to calculate a correction value ΔL (step S4-3). The correction value ΔL is a difference between the correction distance Lb and the relative distance Lc.

  Further, the position detection device 5 determines whether or not the correction value ΔL is equal to or less than the predetermined value Ld (step S4-4). When correction value ΔL is equal to or smaller than predetermined value Ld (YES in step S4-4), predicted position Pi is specified as head position DH (step S4-5).

  On the other hand, if it is determined that correction value ΔL is greater than predetermined value Ld (NO in step S4-4), predicted position Pi is corrected based on correction value ΔL (step S4-6), and the process returns to step S4-2. As described above, when the correction is repeated, the correction value ΔL becomes equal to or less than the predetermined value Ld (YES in step S4-4), so the predicted position Pi is specified as the head position DH (step S4-5).

  The head position DH calculated in this way is output to the image display system 3 and used for image processing of image data. The image display system 3 outputs display data to the display device 11 to display a blind spot image on the inner surface of the pillar.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the position detection system 2 is arranged so that the detection ranges Z2 overlap each other, and the four distance measuring sensors 6 that measure the distance to the head D1 of the driver D who is seated, and the driver D An area in which the head D1 is located is estimated, and among the measurement distances La measured by the distance measuring sensors 6, the measurement distances La measured by the three distance measuring sensors 6 close to the area are selected, and the measurement distances La are measured. The position detection device 5 that calculates the head position DH based on the above is provided. For this reason, the detection accuracy of the head position DH can be improved by optimizing the detection range Z2 of each distance measuring sensor 6. Further, since the head position DH is specified based on the three measurement distances La, the detection ranges Z2 of the distance measurement sensors 6 overlap each other as compared with the case where the measurement distances La measured by all the distance measurement sensors 6 are used. That is, the region where the head position DH can be specified can be widened, and the amount of calculation in the position calculation process can be reduced.

  (2) In the above embodiment, the position detection device 5 sets the predicted position Pi within a range in which the head D1 of the driver D can move, the predicted position Pi, the selected three measurement distances La, and these The predicted position Pi is corrected based on the position of the distance measuring sensor 6 that has measured the measurement distance La. Further, the predicted position Pi that has been corrected is specified as the head position DH. For this reason, without using a special device such as a sensor capable of measuring a relative angle with the head position DH, the measurement distance La measured by the distance measurement sensor 6 and the distance measurement sensor 6 that measures the measurement distance La are measured. The head position DH can be calculated using only the position.

  (3) In the above embodiment, the four distance measuring sensors 6 surround the detection target range Z1 and are respectively provided at positions diagonal to the other distance measuring sensors 6. For this reason, the range in which the detection ranges Z2 overlap is made as wide as possible and the detection range Z2 is made as large as possible, rather than concentrating and arranging the distance measuring sensors 6 in one area such as directly above or on the side of the head D1 of the driver D. Accuracy can be improved.

  (4) In the above embodiment, the position detection device 5 selects three measurement distances La from the shorter distance among the measurement distances La measured by the distance measuring sensors 6. For this reason, since the head position DH can be calculated using the optimum measurement value, the detection accuracy of the head position DH can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second
Since the embodiment has a configuration in which the selection process (step S3) of the first embodiment is changed, detailed description of the same parts is omitted.

  In the second embodiment, three measurement distances La are selected using the pressure-sensitive sensor 20 as the pressure detection means provided in the driver's seat 101 shown in FIG. A known pressure sensor can be used as the pressure sensor 20. For example, the pressure-sensitive sensor 20 includes a pair of resin sheets, a spacer provided between the sheets, a contact portion provided on each sheet, a pressure detection circuit, and the like. When the driver D is seated on the driver's seat 101 and the contact portions come into contact with each other, the pressure is detected. Four pressure sensitive sensors 20 are provided on the front right side, the rear right side, the rear left side, and the front left side of the seat cushion 103 of the driver's seat 101.

  Further, the contact resistance between the contact portions of the pressure sensor 20 changes according to the magnitude of the external pressure, and the pressure detection circuit converts the resistance value into an electrical signal and outputs it to the position detection device 5. The position detection device 5 acquires resistance values from the pressure detection circuit, and calculates the sum of the resistance values of the pressure-sensitive sensors 20. Then, for each pressure sensor 20, the ratio of the resistance value of each pressure sensor 20 to the sum of the resistance values is calculated, and it is determined whether or not the ratio deviates from a preset reference ratio range. If there is a pressure-sensitive sensor 20 that has been determined to deviate from the reference ratio range, it is determined that a pressure deviation has occurred, and it is determined that the driver is tilted in any direction. To do. Even if there is a difference in the ratio of resistance values between the pressure sensors 20, if the ratio does not deviate from the reference ratio range, it is determined that the driver is not in a tilted posture.

  The position detection device 5 has a map 21 that associates the pressure bias direction with the measurement distance La to be selected. Based on this map 21, three distance measuring sensors 6 that are close to the pressure bias direction have measured. Select a measurement distance La. For example, if it is determined that the pressure bias direction is “front right side”, the “first distance sensor FR”, “second distance sensor RR”, and “fourth distance sensor” associated with the direction based on the map 21 are determined. The measurement distances La1, La2 and La4 measured by the distance sensor FL ”are selected. In the figure, the map 21 is a simplified table, but any data may be used as long as the measurement distance La to be selected and the pressure bias direction are associated with each other.

According to the second embodiment, in addition to the effects (1) to (3) described in the first embodiment, the following effects can be obtained.
(5) In the second embodiment, the position detection device 5 acquires a resistance value corresponding to the pressure from the pressure-sensitive sensor 20 that detects the pressure applied to the driver's seat 101 by the load of the driver D. Further, based on this resistance value, the bias direction of the pressure applied to the driver's seat 101 is judged, and the measurement distance La measured by the three distance measuring sensors 6 in the bias direction is selected. For this reason, since the head position DH can be calculated using the optimum measurement distance La by determining the bias direction of the posture of the driver D, the detection accuracy of the head position DH can be improved.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. Note that the third embodiment has a configuration in which only the selection process (step S3) of the first embodiment is changed, and thus detailed description of the same parts is omitted.

The position detection device 5 as direction detection means of the present embodiment receives a right turn detection signal and a left turn detection signal from an ECU (Electronic Control Unit) 30 that controls blinking of the direction indicator lamp 31 of the vehicle 100. When blinking the direction indicator lamp 31 on the right side of the vehicle based on the operation of the driver D, the ECU 30 outputs a right turn detection signal to the position detection device 5. When blinking the direction indicator lamp 31 on the left side of the vehicle, the ECU 30 outputs a left turn detection signal to the position detection device 5. The ECU 30 may be an ECU that acquires a detection value from a steering angle sensor that detects a steering angle of the steering and determines whether the vehicle 100 makes a right turn or a left turn.

  The position detection device 5 performs processing for detecting the head position only when the right turn detection signal and the left turn detection signal are received. The position detection device 5 stores a map (not shown) in which the right turn direction and the left turn direction are associated with the measurement distance La to be selected.

  The position detection device 5 estimates a region associated with the traveling direction based on the traveling direction of the vehicle 100, and selects a measurement distance La measured by the three distance measuring sensors 6 close to the region. For example, when it is determined that the vehicle 100 turns right, the head position D2 tends to be biased to the front left side, and thus the first distance sensor FR, the third distance sensor RL, and the fourth distance sensor FL measured. The measurement distances La1, La3, La4 are selected as data used for calculating the head position.

According to the third embodiment, in addition to the effects (1) to (3) described in the first embodiment, the following effects can be obtained.
(6) In the above embodiment, the position detection device 5 acquires a right turn detection signal and a left turn detection signal from the ECU 30 that detects the traveling direction of the vehicle 100. The position detection device 5 estimates a region associated with the traveling direction based on the traveling direction of the vehicle, and selects the measurement distance La measured by the three distance measuring sensors 6 close to the region. Therefore, since the measurement distance La associated with the traveling direction of the vehicle 100 can be selected based on the map without performing any special calculation, the optimum measurement among the measurement distances La measured by the distance measuring sensors 6 is selected. The distance La can be easily selected.

(Fourth embodiment)
Next, a fourth embodiment embodying the present invention will be described with reference to FIGS. Note that the fourth embodiment has a configuration in which the selection process (step S3) of the first embodiment is changed, and thus detailed description of the same parts is omitted.

  In the present embodiment, selection processing is performed using a camera 40 that captures the head D1 of the driver D and an image processor (not shown) built in the position detection device 5 serving as image processing means. As shown in FIG. 18, the camera 40 is attached in front of the driver D, and is attached so that the imaging region Z6 includes the head D1 of the driver D seated on the driver's seat 101.

  The position detection device 5 acquires image data from the camera 40, performs known image processing such as pattern matching on the image data, and calculates the position of the head 41 in the two-dimensional planar image shown in FIG. . The position of the head 41 is represented by a screen coordinate system (U, V). Since each axis of the screen coordinate system corresponds to a coordinate system (X, Z) representing coordinates in the vehicle interior, the X direction and It can be estimated in which area the head 41 is located in the Z direction.

  For example, when the head position is deviated to the left side, that is, in the anti-X direction, first, measurement is performed by the third distance sensor RL and the fourth distance sensor FL in the anti-X direction of the detection target range Z1. Select the distances La3 and La4. When the third measurement distance La is selected, the measurement distance La measured by the preset distance measuring sensor 6 may be selected, or the measurement distance La measured by the remaining distance measuring sensors 6 may be selected. Of these, the shorter one may be selected. Alternatively, the size of the head 41 in the screen coordinate system is compared with a template obtained by photographing the head D1 in advance or a reference value indicating the size of the head set in advance, and the head position D2 is biased forward. Or whether it is biased backward. In this case, for example, when it is determined that the head 41 is biased forward, the measurement distance La1 measured by the first distance measuring sensor FR is selected, and when it is determined that the head 41 is biased backward. The measurement distance La2 measured by the second distance sensor RR is selected.

According to the fourth embodiment, in addition to the effects (1) to (3) described in the first embodiment, the following effects can be obtained.
(7) In the fourth embodiment, the position detection device 5 acquires image data from the camera 40 that captures an area including the head D1 of the driver D seated on the driver's seat 101, and performs image processing on the image data. The region where the head D1 is located is estimated. Further, the measurement distance La measured by the three distance measuring sensors 6 close to the area is selected. For this reason, the optimal measurement distance La can be easily selected from the measurement distances La measured by the distance measuring sensors 6.

In addition, you may change this embodiment as follows.
In the present embodiment, the distance measuring sensor 6 is embodied as an ultrasonic sensor, but may be an optical sensor such as a laser sensor or a millimeter wave radar.

In the above embodiment, the display device is embodied as a liquid crystal display, but a projector that projects an image on the inner surface of the pillar may be used.
In the above embodiment, the distance measuring sensor 6 may be a sensor that can detect the distance to the head D1 and the direction with respect to the head D1. In that case, a range for specifying the head position may be limited based on the direction with respect to the head D1, and the predicted position Pi may be set and adjusted in the range. In this way, the number of corrections of the predicted position Pi can be reduced.

  In the third embodiment, the position detection device 5 determines the traveling direction based on the ECU 30 that detects the right turn direction and the left turn direction, but may be embodied in the navigation computer 8. That is, the traveling direction of the vehicle 100 may be determined according to the direction of the guidance route searched by the navigation computer 8.

In the fourth embodiment, the camera 40 is attached in front of the driver D, but may be attached at other positions.
In each of the above embodiments, the predicted position Pi is set, and the head position is specified by adjusting the predicted position Pi to match the head position D2. However, the head position may be specified by other methods.

  In each of the above embodiments, four distance measuring sensors 6 are provided, but five or more may be used. Even in this case, among the measurement distances La measured by all the distance measuring sensors 6, three measurement distances La are selected under the above-described conditions.

  In each of the above embodiments, the head position detection system is embodied as a system that detects the head D1 of the driver D seated on the driver's seat 101, but the system that detects the heads of passengers seated on other seats It is good. The head position detection system is configured as the driving support system 1 that displays the blind spot image on the pillar, but may be configured as another driving support system or an occupant protection system.

1 is a schematic diagram of a position detection system according to a first embodiment. The side view of a detection object range. The top view of a detection target range. (A) is a detection range, (b) is a conceptual diagram of the identifiable range. The conceptual diagram of the identifiable range of a comparative example. (A) is a detection range of a comparative example, (b) is a conceptual diagram of the identifiable range of a comparative example. (A) is a detection range of a comparative example, (b) is a conceptual diagram of the identifiable range of a comparative example. The conceptual diagram of the detection target range seen from diagonally. The conceptual diagram of correction | amendment distance. Explanatory drawing of a position calculation process. Explanatory drawing of a position calculation process. The schematic diagram of the vehicle carrying this system. The flowchart explaining the process sequence of this embodiment. The flowchart explaining the process sequence of a calculation process. The top view of the driver's seat provided with the pressure-sensitive sensor of 2nd Embodiment. Conceptual map. Schematic of the position detection system of 3rd Embodiment. The schematic diagram which shows the positional relationship of the camera and driver's seat of 4th Embodiment. The conceptual diagram of the image data which image | photographed the head.

Explanation of symbols

  2 ... position detection system as a head position detection system, 5 ... selection means, position calculation means, direction detection means, image processing means, acquisition means and position detection device as head position detection device, 6, FR, RR, RL, FL: ranging sensor, 20 ... pressure sensor as pressure detecting means, 40 ... photographing device, 100 ... vehicle, D ... driver as occupant, D1, 41 ... head, D2, DH ... head position, La, La1 to La4 ... measurement distance, Ld ... predetermined value as a predetermined distance, Lc ... relative distance, ΔL ... difference, Pi ... predicted position, Z2 ... detection range.

Claims (9)

In the head position detection system that detects the position of the head of the occupant,
At least four ranging sensors arranged so that a part of the detection range overlaps each other, and measuring the distance to the head of the seated occupant;
A selection means for estimating a region where the occupant's head is located, and selecting measurement distances measured by the three distance measuring sensors close to the area among the measurement distances measured by the distance measuring sensors;
A head position detection system comprising: position calculation means for calculating the head position of the occupant based on the selected measurement distance. The head position detection system according to claim 1,
The selection means includes
A head position detection system, wherein the measurement distances measured by three distance measurement sensors are selected from the shorter distances among the measurement distances measured by the distance measurement sensors. The head position detection system according to claim 1,
Pressure detecting means for detecting the pressure applied to the seat by the load of the passenger,
The head position detection system characterized in that the selection means selects the measurement distances measured by the three distance measuring sensors close to the pressure bias direction. The head position detection system according to claim 1,
Direction detection means for detecting the traveling direction of the vehicle,
The selection means estimates a region where the occupant's head is associated with the traveling direction based on the traveling direction of the vehicle detected by the direction detecting unit, and the three distance measuring sensors close to the region include A head position detection system characterized by selecting a measured distance. The head position detection system according to claim 1,
Image processing means for obtaining image data from an imaging device that captures an area including the head of the occupant seated on the seat, and further performing image processing on the image data to estimate the area where the occupant's head is located,
The head position detection system, wherein the selection means selects the measurement distances measured by the three distance measuring sensors close to a region where the occupant's head is located. In the head position detection system according to any one of claims 1 to 5,
The position calculating means includes
Set the predicted position of the occupant's head, based on the predicted position, the measured distance measured by the selected distance sensor, and the positions of the three distance sensors that measured the measured distance, A head position detection system that corrects a predicted position and identifies the corrected predicted position as the head position of the occupant. In the head position detection device that detects the position of the head of the occupant,
Obtaining means for respectively obtaining measurement distances from at least four distance measuring sensors that are arranged so that a part of the detection range overlaps each other and that measure the distance to the head of the seated occupant;
A selection means for estimating a region where the occupant's head is located and selecting measurement distances measured by the three distance measuring sensors close to the region among the measurement distances;
A head position detecting device comprising: position calculating means for calculating the head position of the occupant based on the selected measurement distance. In a head position detection method for detecting the position of the head of an occupant using a distance measuring sensor,
A part of the detection range is arranged so as to overlap each other, the measurement distances are obtained from at least four distance measuring sensors that measure the distance to the head of the seated occupant, and the region where the head of the occupant is located A head position detection method that estimates and selects the measurement distances measured by the three distance measuring sensors close to the region out of the measurement distances, and calculates the head position of the occupant based on the selected measurement distances . In the head position detection program for detecting the position of the head of the occupant using the distance measuring sensor and the control means,
The control means;
Obtaining means for respectively obtaining measurement distances from at least four distance measuring sensors that are arranged so that a part of the detection range overlaps each other and that measure the distance to the head of the seated occupant;
A selection means for estimating a region where the occupant's head is located and selecting measurement distances measured by the three distance measuring sensors close to the region among the measurement distances;
A head position detection program that functions as position calculation means for calculating the head position of the occupant based on the selected measurement distance.

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