JP2007326428A - Parking assisting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a parking space with higher precision by precisely obtaining a distance between an object around a vehicle and the vehicle. <P>SOLUTION: A parking assisting device enables a processing unit 5 to make slit light irradiate a side part of the vehicle 10 from a light emission part 2 for the slit light irradiation, to input an image of the side part of the vehicle captured by a camera 1 mounted in the vehicle 10, to detect a bending point where the photographed slit light is bent in the image, and to calculate the distance between the object around the vehicle and the vehicle 10 from the bending point. Then the parking space is extracted in the side part of the vehicle from the distance to assist a driver for parking. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a parking assistance device that assists a driver in parking by detecting a parking space on a side surface of a road.

  Conventionally, for example, an ultrasonic sensor, a laser radar, and a stereo camera have been used to detect a parking space of a vehicle. Among these, the ultrasonic sensor is used when calculating the distance between the ultrasonic sensor and the object by emitting the ultrasonic wave and measuring the time until the ultrasonic wave is reflected by the object and returns. Such an ultrasonic sensor can detect an object about 1 m away from the vehicle, for example.

  The laser radar is used to calculate the distance between the object and the vehicle by irradiating the periphery of the vehicle with laser light using a laser diode as a light source and detecting reflected light from the object around the vehicle. Such a laser radar can detect an object within a range of, for example, about several tens of meters from the vehicle.

  Furthermore, a stereo camera is used for a driver | operator's parking assistance by image | photographing the vehicle back, for example, and displaying the image | video on a vehicle-mounted monitor. Such a stereo camera is used to calculate the distance to an object projected on an image using the parallax of each image captured by each camera.

  Note that by finding the same point from each image captured by the stereo camera and obtaining the parallax, the focal length of the lens of the stereo camera is f, and the base length (the interval between the two cameras constituting the stereo camera) is l. If the parallax is x, the distance d between the stereo camera and the obstacle can be calculated from d = f × l / x.

  However, in the above conventional technique, when an ultrasonic sensor is used as a sensor for monitoring the periphery of the vehicle, it cannot be detected unless it is a limited obstacle including the closest, and the height difference from the ground like a groove Cannot detect small obstacles. In addition, when a laser radar is used, the mechanism for scanning is large, and the existing technology is poorly mounted on a vehicle. Furthermore, when a stereo camera is used, when the distance between the vehicle and an object around the vehicle is calculated in stereo with parallax due to vehicle movement, the corresponding points (same points) in the two images used for calculation are correctly extracted. If this is not possible, there is a possibility that the perspective relationship of the distance between the object around the vehicle and the vehicle is reversed and calculated. Thereby, there is a possibility that the parking space is erroneously determined.

  An object of this invention is to provide the parking assistance apparatus which can detect a parking space with high precision in view of the said point.

  In order to achieve the above object, the present invention irradiates slit light from a light source (2) mounted on a side portion of a vehicle (10), and shoots mounted at a position away from the light source on the body of the vehicle. The means (1) inputs each image obtained by repeatedly photographing the side part of the vehicle as the vehicle moves, and detects the bending points (31, 32) where the slit light is bent from each image. After calculating the distance between the vehicle peripheral object (11, 12, 41 to 44) and the vehicle based on each bending point of each image, and extracting the parking space in the side part of the vehicle based on the calculated distance, A processing means (5) for setting as a parking target frame for a vehicle in a parking space is provided.

  In this way, when the slit light is applied to the object around the vehicle, the bending point (bending point) of the slit light generated by the parallax between the light source and the photographing means can be photographed. Then, the coordinates of this bending point are detected from the image, and the distance between the vehicle surrounding object and the vehicle is obtained by obtaining the deviation from the slit light when there is no vehicle surrounding object using the coordinates of this bending point. be able to. This bending of the slit light occurs on the surface of an actual vehicle surrounding object, so that the perspective relationship between the vehicle surrounding object and the vehicle can be prevented from being reversed, and an obstacle with a small difference in height from the ground, such as a groove. In addition, it is possible to accurately detect the distance between the vehicle peripheral object and the vehicle.

  The light source used for photographing is preferably installed in the vehicle so that the direction in which the slit light emitted from the light source extends when the light is applied to the ground is perpendicular to the body surface of the vehicle. By doing in this way, the distance from the body surface of a vehicle can be acquired.

  The light source is preferably adapted to irradiate infrared slit light.

  Further, the photographing unit irradiates slit light having a light amount larger than the reflected light amount of sunlight corresponding to the area of one pixel corresponding to the distance to the reflection target (for example, an obstacle). As a result, it is possible to prevent the slit light from being buried in sunlight and making it difficult to capture the slit light with a camera.

  It is preferable that the shutter speed of the photographing unit corresponds to a minimum time during which the slit light can be exposed in the photographing unit. Thus, by shortening the shutter time, it is possible to photograph the slit light more significantly.

  The processing means includes a first image acquisition means (110) for inputting an image photographed by the photographing means as a first image, and irradiating slit light from a light source, and secondly taking an image photographed by the photographing means. Second image acquisition means (120, 130) for inputting as an image, and a difference calculation of data of each image between the first image and the second image, and an image obtained by the difference calculation is acquired as a third image. The third image acquisition means (140), and from among the third images, the bending point of the one showing the slit light is detected as a bending point, and the coordinates of the bending point are acquired. The parallax between the light source and the photographing means is obtained from the coordinates of the bending point corresponding to the reflection at the position where the object does not exist and the coordinates of the bending point corresponding to the reflection at the position where the object around the vehicle exists. Parallax acquisition hand (150) and distance acquisition means (160) for acquiring the distance between the vehicle peripheral object and the vehicle using the parallax value between the light source and the imaging means, and the distance calculation processing in each of these structures May be performed.

  In addition, when a plurality of light sources having different slit light irradiation angles with respect to the road are installed in the vehicle, and the processing of the processing means is a distance calculation process, the processing means is configured to transmit the slit light from the plurality of light sources. Slit light pattern selection means (210) for selecting one of the irradiation angle patterns to be irradiated, and distance calculation drive for performing distance calculation processing based on the irradiation angle pattern of the slit light selected by the slit light pattern selection means It is good also as a structure provided with the processing means (220) and the pattern determination means (230) which determines whether the distance calculation process was performed by all the irradiation angle patterns in the several light source.

  Of each slit light emitted from each of the plurality of light sources, the direction extending when one slit light is applied to the ground is the front side of the vehicle with respect to the lateral direction of the vehicle, and the other slit light is It is preferable that the direction extending when irradiated to the ground is on the rear side of the vehicle with respect to the lateral direction of the vehicle.

  Thereby, in the side part of a vehicle, the distance from a vehicle to the part which becomes a blind spot with a vehicle peripheral object can be detected, and the precision of the parking space to extract can be improved. That is, when the vehicle is viewed from the viewpoint as shown in the top view, it means that the slit light is irradiated in a V shape. Thus, by irradiating slit light from a plurality of light sources, when scanning a side portion of the vehicle, it is possible to reduce a blind spot and detect a detailed parking space.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The parking assistance device shown in the present embodiment is used to detect a parking space and perform parking assistance based on the detected parking space.

  FIG. 1 is a configuration diagram of a parking assistance apparatus according to the first embodiment of the present invention. As shown in this figure, the parking assist device S1 includes a camera 1, a light emitting unit 2, a rudder angle sensor 3, a vehicle speed sensor 4, a processing unit 5, and a display 6. Yes.

  The camera 1 captures the scenery around the vehicle, and for example captures 15 images per second. Each captured image is recognized as a moving image by being continuously displayed. Data of an image photographed by the camera 1 is output to the processing unit 5. In the present embodiment, the lens focal length of the camera 1 is assumed to be f. This lens focal length f is stored in the processing unit 5 in advance.

  Note that the camera 1 is preferably capable of shooting at a wide angle in consideration of shooting a wide range or taking a situation of shooting from the vicinity of a moving vehicle looking for a parking space to the road shoulder. The camera 1 corresponds to the photographing means of the present invention.

  The light emitting unit 2 is a light source for photographing the periphery of the vehicle with the camera 1. That is, when light is emitted by the light emitting unit 2, the light is irradiated around the vehicle, and the camera 1 captures and captures the light reflected around the vehicle. The light emitting unit 2 corresponds to the light source of the present invention.

  Such a light emitting unit 2 includes a light source, a condensing lens that condenses light emitted from the light source, a semi-cylindrical lens having a plano-convex cross section that irradiates light emitted from the condensing lens in a slit shape, and the like. , And is configured. In this configuration, the light emitted from the light source is irradiated around the vehicle as slit light extending in the vertical direction from the convex surface of the semi-cylindrical lens via the condenser lens.

  In addition, an LED that emits infrared light is employed as the light source of the light emitting unit 2. The optical axis of the light source is slightly forward with respect to the longitudinal direction of the vehicle 10.

In addition, since the light quantity of sunlight which is disturbance light is 1 mW / mm < ² > according to the general literature, for example, it is preferable to irradiate the light of a light quantity larger than this light quantity of sunlight. That is, when the light quantity of the slit light reflected by the reflection target or the like is lower than the light quantity of sunlight, the slit light is buried in sunlight, and it becomes difficult to photograph the slit light with the camera 1. Therefore, it is preferable to irradiate slit light having a light amount larger than the reflected light amount of sunlight corresponding to the area of one pixel of the camera 1 according to the distance to the reflection target from the light emitting unit 2.

  In the present embodiment, the camera 1 and the light emitting unit 2 are installed on the left side of the vehicle 10 as shown in FIG. Specifically, as shown in FIG. 1, the camera 1 is fixed to the left side of the body of the vehicle 10, for example, fixed in a direction for photographing a road shoulder. The light emitting unit 2 is fixed to the left side of the body of the vehicle 10 like the camera 1 and is fixed slightly forward with respect to the front-rear direction of the vehicle 10 as described above. Further, the camera 1 and the light emitting unit 2 are mounted at positions separated from each other on the body of the vehicle 10. That is, the distance (interval) between the camera 1 and the light emitting unit 2 is the baseline length l. The value of the baseline length l is stored in the processing unit 5 in advance.

  Thus, when the camera 1 is mounted on the body of the vehicle 10 at a position away from the light emitting unit 2, when the slit light is projected onto the body surface of the vehicle 10, the camera is on the straight line of the projected slit light. 1 may be arranged. Even in such a case, by providing a certain distance between the camera 1 and the light emitting unit 2, an image with parallax is captured by the camera 1 when the slit light is irradiated onto the reflection target. be able to.

  The surface formed by the optical path of the slit light irradiated to the space from the light emitting unit 2 may be an irradiation surface, and the camera 1 may be mounted at a position away from the irradiation surface in the vehicle 10. As described above, even when the camera 1 and the light emitting unit 2 are arranged, the camera 1 can capture the shift of the slit light due to the parallax between the camera 1 and the light emitting unit 2.

  The rudder angle sensor 3 detects a rotation angle when the driver operates the steering. The vehicle speed sensor 4 detects the vehicle speed, that is, the vehicle speed. A signal corresponding to the steering angle detected by the steering angle sensor 3 and the vehicle speed sensor 4 and a signal corresponding to the vehicle speed are respectively input to the processing unit 5 and converted into physical quantities by the processing unit 5. Is done.

  The processing unit 5 calculates the distance between an object existing around the vehicle and the vehicle 10 from the function of photographing the vehicle periphery with the camera 1, the function of irradiating slit light from the light emitting unit 2, and the image photographed with the camera 1. A function, a function of performing parking assistance (pre-processing described later, parking space extraction processing, parking target frame setting processing) using the calculated distance, and a function of displaying parking assistance information on the display 6 are provided. . In the present embodiment, the distance between the object existing around the vehicle and the vehicle 10 is d.

  FIG. 2 shows the configuration of the processing unit 5 having such a function. As shown in this figure, the processing unit 5 includes an input unit 5a, an output unit 5b, a storage unit 5c, a calculation unit 5d, and a CPU 5e. The processing unit 5 corresponds to the processing means of the present invention.

  The input unit 5 a and the output unit 5 b serve as an interface with the camera 1, the light emitting unit 2, the steering angle sensor 3, the vehicle speed sensor 4, and the display 6. The storage unit 5c includes information on the steering angle sensor 3 and the vehicle speed sensor 4, calculation results in the processing unit 5, distance calculation processing, preprocessing program, parking processing for performing each processing such as distance calculation processing, preprocessing, and parking support processing. It is a memory for storing each program such as a support program. The calculation unit 5d and the CPU 5e execute each program.

  The display 6 displays information on the parking space obtained by the processing unit 5 and employs a liquid crystal panel. The indicator 6 may be one already mounted on the vehicle 10. The above is the overall configuration of the parking assistance apparatus S1 according to the present embodiment.

  Next, a method for acquiring the distance between the object around the vehicle and the vehicle 10 by the vertical slit light emitted from the light emitting unit 2 in the parking assist device S1 will be described with reference to FIG. FIG. 3 is an explanatory diagram of a distance measuring method up to an object to be photographed using slit light.

  First, as shown in FIG. 3, the camera 1 and the light emitting unit 2 are installed in the vehicle 10 separated by a distance l. This distance l corresponds to the baseline length l. The value of the baseline length l is stored in advance in the storage unit 5c of the processing unit 5.

  Then, when slit light is irradiated from the light emitting unit 2 and nothing exists in the slit irradiation direction, straight slit light is photographed. However, when the slit light hits the subject 20, the slit light is bent by the subject 20 as shown in FIG. 3, and the camera 1 shoots the bending points 31 and 32 where the slit light is bent. Become.

  That is, there is a shift in the slit light that is shot depending on whether or not the shooting target 20 is present, and this shift is acquired by detecting the bending point. This deviation corresponds to the parallax between the camera 1 and the light emitting unit 2. In the present embodiment, this parallax is assumed to be x.

  As described above, the distance d is obtained from d = f × l / x from each value of the baseline length l, the parallax x, and the focal length f of the camera 1.

  Next, an operation for detecting the parking space of the vehicle 10 and performing parking assistance using the distance measuring method will be described. In the present embodiment, for example, in the situation shown in FIG. 4, a case where parking space detection and parking assistance are performed will be described.

  FIG. 4 is a diagram illustrating a state in which the vehicle 10 operates in search of a parking space. As shown in FIG. 4, two vehicles 11 and 12 are parked over a certain distance on the shoulder of the road. In performing parking assistance in such a situation, it is first necessary to detect a parking space. For this reason, the road shoulder of the road is scanned by moving while irradiating the slit light from the vehicle 10.

  FIG. 5 is a flowchart showing the contents of the distance calculation process. In the present embodiment, as described above, since the vehicle 10 operates while searching for a parking space, for example, when the vehicle speed is less than 10 km / h, the flow shown in FIG. 5 starts according to the distance calculation program.

  In step 110 (first image acquisition means), the camera 1 performs shooting. Data of an image photographed by the camera 1 is input to the processing unit 5. The image obtained in this step is referred to as image A (corresponding to the first image of the present invention).

  In step 120, slit light is irradiated. That is, when a signal for irradiating the light emitting unit 2 with slit light is input from the processing unit 5, irradiation of slit light extending in the vertical direction from the light emitting unit 2 is performed. This slit light is applied to the shoulder of the road from the side of the vehicle 10.

  In step 130, photographing is performed by the camera 1. That is, the vehicle periphery is photographed in a state where the slit light is irradiated in step 120. In the present embodiment, the shutter of the camera 1 is a high-speed shutter. The shutter speed is preferably a minimum time during which the slit light can be exposed. Let the image obtained in this step be an image B (corresponding to the second image of the present invention).

  In addition, after imaging | photography, irradiation of slit light is stopped by the instruction | command from the processing unit 5 to the light emission part 2. FIG. Further, the means relating to the processing of steps 120 and 130 corresponds to the second image acquisition means of the present invention.

  In step 140 (third image acquisition means), a difference calculation between the image A and the image B is performed. Specifically, the difference between the pixel value data (RGB values) between the image A and the image B is obtained. Thereby, a difference image C (corresponding to the third image of the present invention) in which only the irradiated slit light is reflected can be obtained.

  The accuracy of the distance between the object obtained in the following steps and the vehicle 10 depends on the base line length l and the number of pixels of the camera 1 as in the case of using a stereo camera, but the bending of the slit light is reversed. Since there is no possibility, the perspective relationship between the object and the vehicle 10 will not be reversed.

  In step 150 (parallax acquisition means), a bending point is detected. Specifically, in the image showing the slit light in the difference image C, a place (bending point) where the object is not present and the object is present is detected. In other words, in order to obtain the deviation between the position of the slit light when there is no object and the position of the actually photographed slit light, the bending point of what shows the slit light is acquired from the difference image C. And the parallax x of the camera 1 and the light emission part 2 is acquired based on the coordinate of this bending point.

  In this embodiment, an arbitrary point is set in the difference image C, and the point is moved in the image C to find an object indicating slit light. Then, it is moved along the slit light found in the difference image C, and the coordinates of the portion where the slit light is bent are obtained. In the present embodiment, it is said that the portion where the slit light is not linear is bent. That is, a portion where the slit light displayed in the difference image C is bent or interrupted by an object or the like is called a bending point (see FIG. 3). Then, the parallax x is obtained from the coordinates of the obtained bending points.

  In step 160 (distance acquisition means), the distance between the object and the vehicle 10 is calculated. That is, the baseline length l and the focal length f of the lens are known in advance, and the parallax x is obtained in step 150 above. Further, as described above, the distance d from the camera 1 to the object is obtained by d = f × l / x. Therefore, the distance d is obtained by substituting each value into this equation. Thus, this flow ends.

  Then, the distance calculation flow described above is performed along with the progress of the vehicle 10 as shown in FIG. 4, so that the position 50 (in FIG. 4) of each side portion of the vehicles 11 and 12 parked on the shoulders of the road. A plurality of distances d between each black circle) and the vehicle 10 are acquired.

  FIG. 6 is a diagram schematically showing a space between two vehicles 11 and 12 parked on the shoulder of the road. As shown in this figure, there may be a groove 44 or a stone 43 between the vehicles 11 and 12. In such a case, the distance calculation process can also obtain the distance between the curb 41, the roadside tree 42, and the vehicle 10 and the distance between the groove 44, the stone 43, and the vehicle 10 as an obstacle.

  4 and 6, the situation where two vehicles 11 and 12 are parked on the shoulder of the road is depicted. However, in the case where neither of the vehicles 11 and 12 exist or only one of them is present. There may be cases where it exists. Even in such a case, the distance d between the object existing on the shoulder of the road and the vehicle 10 is calculated by the distance calculation process.

  Next, an operation for assisting parking of the vehicle 10 will be described based on the distance d between the vehicle 10 and the object present on the road shoulder acquired as described above. First, the pre-processing before parking assistance will be described with reference to FIG.

  FIG. 7 is a flowchart showing the contents of the pre-processing. Here, the pre-processing is processing executed when the vehicle 10 passes through the road as shown in FIG. 4 in order to check information on obstacles such as the two vehicles 11 and 12 parked. It is. Therefore, the processing unit 5 executes the preprocessing program according to the flowchart shown in FIG. In the present embodiment, this pre-processing program is automatically started when the vehicle speed falls below, for example, 10 km / h.

  First, after resetting a counter corresponding to time (step 210), vehicle speed data and steering angle data are acquired from the vehicle speed sensor 4 and the steering angle sensor 3 (steps 220 and 230), and based on the vehicle speed data and steering angle data. The vehicle position is calculated (step 250). In calculating the vehicle position, GPS (Global Positioning System) may be used.

  Here, it is determined in step 240 whether or not the vehicle speed is less than 10 km / h because it is assumed that the vehicle 10 is looking for a parking space. In addition, when the vehicle speed exceeds 10 km / h, this pre-processing is terminated because the vehicle 10 is not searching for a parking space. In order to start again from the start, the counter value is reset, and all the information stored so far becomes invalid.

  Then, the vehicle position acquired in step 250 is stored in the area of the address indicated by the current counter value in the storage unit 5c (step 260). At the same time, the camera 1 also takes a picture (step 270), and the taken picture is stored in the area of the address indicated by the current counter value in the storage unit 5c (step 275). At the same time, the distance d obtained by the distance calculation process is acquired (step 280), and this distance information is stored in the area of the address indicated by the current counter value in the storage unit 5c (step 285). Thereafter, the counter value is incremented (step 290).

  As described above, the vehicle position, the camera image, and the distance information are stored in the area indicated by the same address in the storage unit 5c.

  Thereafter, the gear position of the transmission is determined (step 295), and if the transmission is set to a gear position other than reverse, the process returns to step 220 and the pre-processing operation is performed until the transmission is set to reverse. repeat. Further, when the transmission is set to reverse (back), parking support processing is started. Hereinafter, this parking assistance process will be described.

  FIG. 8 is a flowchart showing the contents of the parking support process. First, a parking space existing on the shoulder of the road is extracted (step 310), a shooting position (camera image position) of the camera 1 corresponding to the center of the parking space is obtained, and an image corresponding to the obtained shooting position is stored. It is read from the unit 5c (READ) (step 320), and a camera image (video as a parking space) is displayed on the display 6 (step 330), and the parking target frame is superimposed on this display image. Setting processing is performed (step 340). The vehicle 10 is automatically steered, for example, according to the result of the parking target frame setting process.

  Next, specific processes of the parking space extraction process (step 310) and the parking target frame setting process (step 340) in the parking support process will be described.

  FIG. 9 is a flowchart showing the contents of the parking space extraction process. First, the distance information for each address (that is, the distance to the object existing on the road shoulder) and the vehicle position stored in the above-described pre-processing and the vehicle position are read from the storage unit 5c (steps 311 and 312), and the road shoulder distance information is obtained. The distribution state of is calculated. Subsequently, 3D mapping of the distance information is performed (step 313). Specifically, by plotting the distance to the vehicle peripheral objects (the parked vehicles 11, 12 and the curb 41, etc.) existing on the road shoulder with respect to the traveling direction of the vehicle 10 in a three-dimensional manner, Perform dimension mapping.

  Thereafter, a parking space in which the vehicle 10 can be parked is extracted from the 3D mapping of the road shoulder acquired in step 313. That is, the position and size of the road shoulder space are extracted.

  For example, when a space is formed in the side portion of the vehicle 10, that is, the shoulder of the road, it is estimated that there is no obstacle parking vehicle as shown in FIG. Accordingly, the “no-parking-vehicle pattern” is determined as the parked vehicle pattern.

  Moreover, when the parked vehicle 11 exists only in the back side of the vehicle 10, as FIG. 11 shows, it estimates that only the back side parked vehicle 11 exists. Accordingly, the “rear side parked vehicle only pattern” is determined as the parked vehicle pattern.

  Furthermore, when the parked vehicle 12 exists only in the front side of the vehicle 10, as FIG. 12 shows, it estimates that only the front side parked vehicle 12 exists. Along with this, the “front-side parked vehicle only pattern” is determined as the parked vehicle pattern. Thus, the parking space extraction process ends, the process proceeds to step 320 shown in FIG. 8, and after step 330 is executed, the parking target frame setting process is executed at step 340.

  FIG. 13 is a flowchart showing the contents of the parking target frame setting process. In the following description, the dimension between the parked vehicles 11 and 12 is L, and the central portion of the parking space is at a position L / 2 from the parked vehicles 11 and 12. Also, let Tc be the passage timing passing through the central portion.

  First, the selection in step 341 is a value Lc based on the overall length of the general vehicle (dimension in the vehicle longitudinal direction) as a parameter D used in the calculation for obtaining the photographing position of the camera 1 to be described later, The value Wc (not shown) based on the full width of the vehicle (the dimension in the vehicle left-right direction) is selected.

  And if it determines with it being the case of parallel parking in step 341, it will set the display frame for parallel parking in step 342a, and if it determines with it being the case of parallel parking, it will be the display frame of parallel parking in step 342b. Set up.

  Next, the parameter D is obtained from one of Lc and Wc (steps 343a and 343b). Here, when determining the parameter D, Lc and Wc are multiplied by n, and this n is a positive integer (D = n × Lc, D = n × Wc). The parameter D indicates the minimum space length required for the own vehicle for parallel parking and parallel parking. Further, the positive integer n is a coefficient by which the minimum space length D is multiplied when calculating from the total length or the entire width of the own vehicle. For example, in the case of an Ackermann-Jantho vehicle, the minimum space length D is more ideal than the theoretical formula. Is easily calculable.

  Actually, since it is necessary to add a safety margin for preventing an emergency collision to the minimum space length D, the positive integer value n needs to be determined empirically.

  Next, the process proceeds to step 344, where conditional branching is performed based on the parked vehicle pattern determined by the obstacle position calculation process described above. In the present embodiment, as the parked vehicle pattern, “no parked vehicle pattern” (see FIG. 10), “rear side parked vehicle only pattern” (see FIG. 11), “front side parked vehicle only pattern” (see FIG. 12). And “Pattern with / without parked vehicle” (see FIG. 4).

  For example, in the case of the “no-parking vehicle pattern”, since there is no obstacle that restricts the parking space, 1/2 of the minimum space length D is reduced with reference to the current position of the vehicle 10 that is the own vehicle (step 346a). The position (far from the vehicle 10) is set to the center of the target parking space (the position of the parking frame) (step 347a).

  Further, in the case of the “rear side parked vehicle only pattern”, when the distance L from the closest end of the rear parked vehicle 11 to the current vehicle position is not more than twice the minimum space length D (step 345: NO). Then, with the closest end of the rear parked vehicle 11 as a reference (step 346b), a position obtained by adding 1/2 of the minimum space length D is set as the position of the parking frame (step 347b).

  Furthermore, when it is larger than twice the minimum space length D (step 345: YES), a position obtained by subtracting 1/2 of the minimum space length D with respect to the current vehicle position is set as the parking frame position. At this time, the coefficient “2” multiplied by the minimum space length D is not limited to 2. For example, when performing parallel parking in actual use, if you attempt to park in a parking space that is completely free of obstacles ahead of one parked vehicle, The distance is only assumed to be twice the minimum space length D. In the case of a small vehicle having a total length of 4 m and the positive integer being 1.5, when the coefficient is 2, the condition is branched at a portion of 3 m from the rear parked vehicle.

  Further, in the case of the “front parked vehicle only pattern”, the farthest end of the forward parked vehicle 12 is used as a reference (step 346c), and the position obtained by subtracting 1/2 of the minimum space length D is set as the position of the parking frame (step 347c).

  In the case of the “front and rear parked vehicle pattern”, when the distance L from the closest end of the rear parked vehicle 11 to the farthest end of the front parked vehicle 12 is longer than twice the minimum space length D (step 348). : YES), a position obtained by subtracting 1/2 of the minimum space length D with respect to the closest end of the forward parked vehicle is set as the position of the parking frame (steps 346c and 347c).

  When the distance is less than twice the minimum space length D (step 348: NO), the distance from the closest end of the rear parked vehicle 11 to the farthest end of the front parked vehicle 12 with the farthest end of the front parked vehicle 12 as a reference. The position obtained by subtracting 1/2 of the distance L is set as the parking frame position (step 349).

  As described above, the position of the parking frame is acquired. Thereafter, parking assistance is provided to the driver by, for example, displaying an image of the set position of the parking frame on the display device 6 as parking assistance information. Further, the vehicle 10 may be parked in a parking space by automatic steering.

  As described above, in the present embodiment, when the vehicle peripheral objects 11, 12, 41 to 44 are present around the vehicle 10, the vehicle peripheral objects 11, 12, 41 to 44 are photographed by irradiating the slit light. At the same time, bending points 31, 32 where the slit light is bent are detected from the captured image, and the distance d between the vehicle surrounding objects 11, 12, 41-44 and the vehicle 10 is calculated based on the bending points 31, 32. It is a feature. Since the bending of the slit light occurs on the surfaces of the actual vehicle surrounding objects 11, 12, 41 to 44, the perspective relationship between the vehicle surrounding objects 11, 12, 41 to 44 and the vehicle 10 is reversed when calculating the distance. Can be prevented. Further, since the parallax x is obtained from the coordinates of the bending point from the captured image, the distance between the vehicle surrounding objects 11, 12, 41 to 44 and the vehicle 10 can be obtained with high accuracy. In addition, parking assistance can be provided to the driver using the distance thus obtained. As described above, since the distance between the vehicle surrounding objects 11, 12, 41 to 44 and the vehicle 10 can be obtained with high accuracy, the parking space for parking the vehicle 10 can be detected with high accuracy.

(Second Embodiment)
In the present embodiment, only parts different from the first embodiment will be described. This embodiment is characterized in that a plurality of light emitting units 2 having different irradiation angles are used. As described above, when a plurality of light emitting units 2 are used, the distance d to the object existing on the road shoulder is calculated according to the flow shown in FIG.

  First, in step 410 (slit light pattern selection means), a slit light pattern is selected. That is, from among the plurality of light emitting units 2, which light emitting unit 2 emits the slit light is selected.

  In step 420 (distance calculation processing means), a distance calculation process is performed. That is, according to the flow shown in FIG. 5, the detection of the object existing on the road shoulder and its distance d are obtained. When this process is performed, the light emitting unit 2 selected in step 410 is used. Note that if no inflection point is found from the difference image C, no object is present on the road shoulder.

  In step 430 (pattern determining means), it is determined whether or not all the patterns of the slit light pattern have been completed. That is, it is determined that the distance calculation process has been performed in step 420 using all the light emitting units 2 installed in the vehicle 10.

  If all the patterns are not completed in this step, the process returns to step 410, and another light emitting unit 2 is selected. Further, when all the patterns are completed, this flow ends.

  As described above, a plurality of light emitting units 2 are prepared, and slit light is irradiated from each light emitting unit 2 at different irradiation angles. This eliminates blind spots when scanning the road shoulder from the vehicle 10 with slit light, so that the road shoulder space and obstacles can be reliably detected, and the distance between the obstacle and the vehicle 10 is calculated. can do.

(Other embodiments)
In each of the above embodiments, the distances between the vehicles 11 and 12 and the curb 41 etc. that are parked as the vehicle peripheral objects and the vehicle 10 are calculated, but steps on the road, wheel stops, and the like can also be detected. That is, since the side part of the vehicle is scanned by the slit light, the side part of the vehicle can be grasped three-dimensionally (three-dimensionally).

  In each of the above embodiments, the slit light is irradiated in the vertical direction with respect to the body surface. However, the irradiation angle of the slit light is not limited to the vertical direction, and may be irradiated with an angle with respect to the vertical direction. Absent. When the slit light is irradiated on the reflection object, if the parallax of the slit light occurs in the image to be shot, the bending point where the slit light bends can be detected from the image, and based on this bending point The distance between the obstacle and the vehicle 10 can be calculated. From the viewpoint of scanning the road shoulder with the slit light as the vehicle 10 travels, the slit light preferably extends in the vertical direction.

  As shown in the second embodiment, when a plurality of light emitting units 2 are used, for example, slit light is emitted from the light emitting unit 2 installed on the side of the vehicle 10 shown in FIG. The slit light is irradiated to the rear side of the vehicle 10 from another light emitting unit 2 installed on the side of the vehicle 10. That is, when the vehicle 10 is viewed from the ground side, the slit light is irradiated so that the direction in which each slit light is irradiated when the ground is irradiated is V-shaped. Thereby, detailed parking space detection in the vehicle 10 is possible without a blind spot. Further, when the parking space is detected by one slit light as in the first embodiment, the direction that extends when the slit light emitted from the light emitting unit 2 is applied to the ground is perpendicular to the body surface of the vehicle 10. By making it become, it can reduce a blind spot.

  In each said embodiment, although the timing which performs a parking assistance process is determined based on the vehicle speed of the vehicle 10, you may make it perform a parking assistance process at another timing. For example, the parking assistance process may be started at the timing when the vehicle 10 enters the parking lot in conjunction with the navigation device. It is also possible for the driver to perform an operation for starting the parking assistance process.

  Further, when the vehicle 10 is stopped, the slit light is not irradiated from the light emitting unit 2. Thereby, it is possible to prevent interference between a plurality of systems.

  When slit light is not photographed by the camera 1, the processing unit 5 may determine that there is an obstacle at the location. That is, it corresponds to the case where slit light is accumulated in water, glass, a mirror, a polished body, a precipice, etc. In this case, it is determined that there is an object on the side of the vehicle and there is no problem.

  By matching the slit light emitted from the light emitting unit 2 with the track of the edge when the door opens, the vehicle 10 can determine whether or not it can collide with an obstacle when the door is opened. Moreover, if slit light is irradiated above the vehicle 10 (toward the ceiling), it can also be used for opening / closing confirmation of hatches and trunks. In this case, the height of the parking space can be detected as in the above embodiments. As a result, it is possible to determine whether or not to enter the multi-story parking lot and whether or not to pass under the overpass.

  In each of the above-described embodiments, the side surface of the vehicle 10 is scanned according to the vehicle speed of the vehicle 10. However, for example, when the vehicle 10 approaches an intersection, a two-wheeled vehicle to be caught can be detected. In this case, the side surface of the vehicle 10 may be scanned in accordance with the vehicle speed, or the vehicle 10 may be scanned when the vehicle approaches the intersection in conjunction with the navigation device.

  In each of the embodiments described above, the slit light extending in the vertical direction from the light emitting unit 2 is irradiated, but it is not limited to the slit light but may be a collection of spot lights (dotted line). Further, an arbitrary mark may be irradiated instead of spot light or spot light.

  In each said embodiment, although the infrared light which does not become a driving | operation obstacle of another vehicle is used as slit light irradiated from the light emission part 2, you may use visible light as slit light.

  Further, the mounting position of the light emitting unit 2 and the camera 1 is not limited to the body on the side of the vehicle 10, and any parallax may be generated as a result of movement at any position and direction on the vehicle 10. .

  The camera 1 and the light emitting unit 2 may be installed in some or all directions of the vehicle 10.

  Also, by comparing the curve by the reflection of the slit light imaged by the camera 1 with the curve when there is no reflection target, obtaining the coordinates of the points that are different, that is, not matching, and performing the distance calculation process, It is also possible to calculate the distance to the reflection target.

  The steps shown in each figure correspond to means for executing various processes.

It is a lineblock diagram of the parking assistance device concerning a 1st embodiment of the present invention. It is a block diagram of the processing unit shown by FIG. It is explanatory drawing of the ranging method to the imaging | photography target object by slit light. It is the figure which showed a mode that the vehicle searched and searched for parking space. It is a flowchart which shows the content of the distance calculation process. It is the figure which showed typically the space between the two vehicles parked on the road shoulder. It is the flowchart which showed the content of the pre-processing. It is the flowchart which showed the content of the parking assistance process. It is the flowchart which showed the content of the parking space extraction process. It is the figure which showed the condition where an obstruction does not exist on the road shoulder. It is the figure which showed the condition where an obstruction (parking vehicle) exists in the back side of a vehicle. It is the figure which showed the condition where an obstruction (parking vehicle) exists in the front side of a vehicle. It is the flowchart which showed the content of the parking target frame setting process. In 2nd Embodiment, it is a flowchart which shows the content of the distance calculation process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Camera as imaging | photography means, 2 ... Light emission part as light source, 5 ... Processing unit as processing means, 10 ... Vehicle, 11, 12, 41-44 ... Vehicle peripheral object, 31, 32 ... Bending point, 110 ... First image acquisition means, 120, 130 ... second image acquisition means, 140 ... third image acquisition means, 150 ... parallax acquisition means, 160 ... distance acquisition means, 410 ... slit light pattern selection means, 420 ... distance calculation processing means 430 ... Pattern determining means.

Claims (8)

The light source (2) mounted on the side of the vehicle (10) is irradiated with slit light, and the vehicle is moved by the photographing means (1) mounted on the vehicle body at a position away from the light source. Accordingly, each image obtained by repeatedly photographing the side portion of the vehicle is input, and the bending points (31, 32) at which the slit light is bent are detected from the images, and each of the images is displayed. After calculating the distance between the vehicle peripheral object (11, 12, 41 to 44) and the vehicle based on the bending point, and extracting the parking space in the side portion of the vehicle based on the calculated distance, the parking space A parking support apparatus comprising processing means (5) for setting as a parking target frame of the vehicle. The said light source is installed in the said vehicle so that the direction extended when the said slit light irradiated from the said light source is irradiated to the ground and the body surface of the said vehicle become perpendicular | vertical. The parking assistance apparatus according to 1. The parking support device according to claim 1, wherein the light source emits infrared slit light. The said imaging | photography means irradiates slit light with a light quantity larger than the reflected light quantity of sunlight corresponding to the area for one pixel according to the distance to reflection object, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. Parking assistance device as described in one. When photographing the periphery of the vehicle with the photographing unit in a state where the slit light is irradiated from the light source, the shutter speed of the photographing unit corresponds to a minimum time during which the slit light can be exposed to the photographing unit. The parking assistance device according to any one of claims 1 to 4, wherein the parking assistance device is provided. The processing means includes
A first image obtaining means (110) for inputting an image photographed without irradiating the slit light by the photographing means as a first image;
Second image acquisition means (120, 130) for irradiating the slit light from the light source and inputting an image photographed by the photographing means as a second image;
A third image acquisition means (140) for performing a difference calculation of data of each image between the first image and the second image, and acquiring an image obtained by the difference calculation as a third image;
From the third image, a position where the slit light is bent is detected as the bending point, and the coordinates of the bending point are obtained. From the position where the vehicle peripheral object does not exist among the bending points. A parallax obtaining unit (150) for obtaining a parallax between the light source and the photographing unit from the coordinates of the bending point corresponding to the reflection of the vehicle and the coordinates of the bending point corresponding to the reflection from the position where the vehicle peripheral object exists. ,
Distance acquisition means (160) for acquiring a distance between the vehicle peripheral object and the vehicle using a parallax value between the light source and the photographing means, and performing distance calculation processing by each of these means The parking assistance device according to any one of claims 1 to 5, characterized in that: It has a plurality of light sources having different irradiation angles of the slit light,
The processing means includes
Slit light pattern selection means (410) for selecting one of the plurality of light sources;
Distance calculation processing means (420) for performing the distance calculation processing based on the slit light selected by the slit light pattern selection means;
The parking assistance device according to claim 6, further comprising: a pattern determination unit (430) that determines whether or not the distance calculation processing has been performed for all of the plurality of light sources. Of each slit light emitted from each of the plurality of light sources, the direction extending when one slit light is applied to the ground is the front side of the vehicle with respect to the lateral direction of the vehicle, and the other The parking assist device according to claim 7, wherein a direction extending when the slit light is applied to the ground is on a rear side of the vehicle with respect to a lateral direction of the vehicle.

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