JP2002107453A - Beam sweeping radar device, moving body, object detecting device in fixed measuring area and contour measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly exclude snow and dust from a radar device for detecting an object position in a measuring area by using a laser radar. SOLUTION: A laser beam is swept in the θ direction in the measuring area, the distance r up to an object in respective θpositions from the reflected light is measured, and r(θ) of an r-θ polar coordinate surface is determined. The r(θ) is processed by and adaptive rank filter, re(θ) is calculated, and this is used as object position information on the measuring area. That is, r-θ polar coordinates are transformed into r-l coordinates by l=∫0θrdθ, and in the r-l coordinates, respective l are processed by a median filter of ±ΔL of both side ranges with these as a center position, and the output r is used as distance information up to the object in θ of inverse conversion of the l.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam sweep type radar apparatus, a moving body equipped with the same, an object detecting apparatus in a fixed measuring area, and a contour measuring apparatus. The present invention relates to a radar device that can be appropriately excluded, a moving object equipped with the radar device, an object detection device in a fixed measurement area, and a contour measurement device.

[0002]

2. Description of the Related Art A predetermined measurement area is defined on a polar coordinate plane of r-.theta. With the origin of the laser radar as an origin, and a laser beam emitted from the laser radar in the r direction is swept in the .theta. A laser radar device that measures the distance from a reflected light to an object at each θ position as r (θ) and obtains object position information in a measurement area is known.

[0003]

When this laser radar apparatus is used outdoors, dust and soaring objects such as snow and so on, depending on the weather, reflect the laser light beam and generate noise on the image, depending on the weather. Has become. In particular, snow is white and has a high reflectance, and with this laser radar device, even if the near object has a small size, it is difficult to remove it because the expected angle to the origin is large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a beam sweeping radar apparatus capable of appropriately detecting unnecessary objects such as snow and dust and detecting an existing object in a measurement area, a moving body equipped with the same, and an object in a fixed measurement area. It is to provide a sensing device and a contour measuring device.

[0005]

According to the beam sweep type radar apparatus of the first invention, a predetermined measurement area is defined by a polar coordinate plane of r-θ with the origin of the position of the beam sweep type radar. While sweeping the beam emitted in the r direction from the sweep type radar in the θ direction, the distance from the reflected beam from the beam reflecting object to the beam reflecting object at each θ position is r.
It is measured as (θ). Then, in the beam sweeping radar apparatus, the size of each reflecting object is determined based on r (θ) and the range amount of θ in which substantially the same r (θ) is maintained in the θ direction. When it is determined that the dimension is not more than the predetermined value, the distance at each θ within the range of θ of the reflecting object is changed to r (θ) related to θ before and after the reflecting object in the θ direction, Object position information of the measurement area is collected.

[0006] The beam of the beam sweep type radar device includes a light beam such as a laser beam and an LED beam, an ultrasonic wave, a millimeter wave, a microwave, and the like. The sweep of the beam in the θ direction is
Normally, a beam is generated and annihilated at equal time intervals, and the beam is emitted in the r direction at equal angular intervals in the θ direction.However, the generation and annihilation are not repeated alternately, but a continuous generation type is used. Alternatively, a method of measuring r at equal angular intervals in the θ direction by software processing may be used. The sweep is usually
A reciprocating sweep that reciprocates right and left is performed. In this case, the beam may be emitted only on the outward path, or may be emitted on both the outward path and the return path. The sweep period is, for example, 0.1 to
1.0 second.

In the first aspect of the present invention, the closer the object in the measurement area is to the beam-sweep type radar, the greater the possible angle of the object relative to the origin of the r-θ polar coordinate plane, and the possible angle in the r-θ polar coordinate plane The magnitude of Ω cannot be considered as the magnitude of the actual size of the object as it is, and it becomes difficult to exclude a small-diameter object such as snow from the information of r (θ). r
(Θ), and approximately the same r (θ) is maintained in the θ direction θ
The size of each reflective object can be determined based on the range amount of the reflective object.When the size of the reflective object whose size has been determined in this way is determined to be equal to or smaller than a predetermined value, each of the reflective objects within the range of θ is determined. If the distance in θ is changed to r (θ) related to θ before and after the reflecting object in the θ direction, the object is excluded from detection targets.

According to the beam sweep type radar apparatus of the second invention, the predetermined measurement area is defined by the polar coordinate plane of r-θ with the origin of the position of the beam sweep type radar, and is set in the r direction from the beam sweep type radar. The distance from the reflected beam from the beam reflecting object to the beam reflecting object at each θ position is measured as r (θ) while sweeping the beam radiating to the θ direction. In the beam sweeping radar apparatus, l = f (θ) for converting the r-θ polar coordinate plane to the rl coordinate plane is defined, and the conversion of f (θ) is used to define r (θ) on the r-θ polar coordinate plane.
Is r (l) on the rl coordinate plane, and r on the rl coordinate plane
(L) Q any point on the (to. The l coordinates of Q and Lc), ± the l direction to Lc [Delta] L ([Delta] L is a constant) consider the scope of, ∫ _{-Delta L} ^l r (l) Dl = (1
_{/ 2) · ∫ L c-} ΔL Lc + ΔL r a (l) · dl satisfies l of a medl, Lc = f (θc) and me
.theta.c and .theta.m, where dl = f (.theta.m), are correlated with each other in a relation A. The distance re (.theta.) to the measurement object at each .theta. on the polar coordinate plane of r-.theta.
And r (θm) for θm related by relation A, ie, re (θ) = r (θm) (where,
θm is related to θ by a relation A when θ = θc. ) And re (θ) are set as the object position information of the measurement area.

In the second invention, the closer the object in the measurement area is to the beam-sweep type radar, the greater the estimated angle of the object relative to the origin of the r-θ polar coordinate plane, and the estimated angle on the r-θ polar coordinate plane. The magnitude of Ω cannot be considered as the magnitude of the actual size of the object as it is, and it becomes difficult to exclude a small-diameter object such as snow from the information of r (θ). On the other hand, by setting an appropriate conversion formula of l = f (θ), a quantity l different from the expected angle Ω of the object with respect to the origin is derived, and the object is evaluated fairly based on this l. It becomes possible. Then, re (θ) = r (θm) as a concept of the rank filter is calculated, and re (θ) is used as the object position information in the measurement area, so that it is included in the object position information based on r (θ). Unnecessary objects can be removed.

In the above-mentioned reflected beam which emits a beam at regular angular intervals, the collection of r (θ) is not continuous with respect to θ but discrete, for example, at regular angular intervals. When only r (θ) of the existing θ is converted to r−1, r (l) also becomes discrete.
In the calculation of (θ), if necessary, r (θ) adjacent in the θ direction on the r-θ pole seat surface and r (l) adjacent in the l direction on the rl seat surface. ) Are connected by an appropriate connection line such as a straight line. The rank of the rank filter may be a number when the maximum value is set to rank 1 and the number is assigned in order from the maximum value to the minimum value. It is assumed that the number may be the number that is assigned in order from the value to the maximum value.

According to the beam sweep type radar apparatus of the third invention, in the beam sweep type radar apparatus of the second invention,
If l = f (θ), f (θ) is ∫ ₀ ^l r · dθ.

[0012] By defining the l = f (θ) = ∫ 0 l r · dθ and f (θ), l-direction length of each portion of r (l) in the r-l coordinate plane in the measurement area It has a linear relationship with the length of the object. Therefore, unnecessary objects in dimensions can be easily removed or extracted based on the length in the l direction for each part of r (l) on the rl coordinate plane.

According to the beam sweep type radar apparatus of the fourth invention, in the beam sweep type radar apparatus of the third invention,
When the maximum size of an object to be excluded from the measurement target object in the measurement area is Sr, ΔL is an amount corresponding to Sr.

Sr is the maximum size of an object to be excluded from the object to be measured, for example, snow or dust.

According to the beam sweep type radar apparatus of the fifth invention, in the beam sweep type radar apparatus of the fourth invention,
Point P on r (θ) on the r-θ polar coordinate plane and r on the rl coordinate plane
(L) Assume that the point Q on the upper side is related by f (θ), the θ coordinate of P is θp, the l coordinate of Q is lq, and r
e (θ) is obtained by processing r (θ) with an adaptive rank filter. When the central value is θp, the size of the adaptive filter is Rw + Lw, and Rw
And Lw are ± ΔL in the l direction with respect to Q on r (l).
And the rank T is Lc = 1q,
That is, θc = θp, θm related to θc by the relation A is obtained, and further, me corresponding to this θm is obtained.
dl, and an equation using this medl: T = ∫
_medl ^{Lc + ΔL} r · dθ.

By processing r (θ) by an adaptive rank filter, re (θ) can be obtained from r (θ).

According to the beam sweep type radar apparatus of the sixth invention, in the beam sweep type radar apparatus of any of the second to fifth aspects, an object measurement image (hereinafter referred to as an object measurement image) in a measurement area based on re (θ). , "First image").

The evaluator can visually and efficiently judge the position of the object in the measurement area by looking at the first image.

According to the beam sweep type radar apparatus of the seventh invention, in the beam sweep type radar apparatus of the sixth invention,
Frames each including the first image as one screen are generated at discrete time intervals, and a plurality of frames within a predetermined time including the first frame at time t1 are subjected to the maximum value filter processing to generate frames (hereinafter, referred to as “ 2) is generated, and the second frame is presented as a frame at time t1.

Since floating objects such as snow and dust move relatively quickly with respect to other objects in the measurement area, a plurality of (for example, three) first frames (for example, three) are arranged at appropriate intervals in the time direction. For the first frame, normally, a plurality of frames arranged in order in the time direction will be selected. However, even if a plurality of frames in a non-sequential order are selected, that is, a plurality of frames arranged in a discrete order are selected. ), There is a high possibility that one of them has disappeared. Therefore,
Maximum value filtering (= each θ) for a plurality of frames
Means that r in the frame having the largest r is selected from a plurality of frames. ), By selecting the distance in the frame where the distance r at each θ position is the maximum as the distance at each θ position, these floating substances can be more clearly removed.

The moving object of the eighth invention is equipped with the beam sweeping radar device of the second to seventh invention, and detects an obstacle ahead in the moving direction.

The moving body is, for example, an automatic unmanned vehicle. The equipped beam-sweep type radar device detects a person or a car that has entered the front running path. When the beam sweep type radar device is mounted on a moving object, in the application of the maximum value filter to a plurality of frames of the fourth image,
With the movement of the moving body, the measurement area corresponding to each frame will be different, but since the sweep time interval is sufficiently small, there is no problem in extracting an effective object.

A ninth aspect of the present invention is directed to an object detection apparatus in a fixed measurement area, which is equipped with second to seventh beam sweep type radar devices, and detects an object in the fixed measurement area.

A fixed measurement area means that the measurement area is fixed. The object detection device in the fixed measurement area detects, for example, entry of a person or a person into a car or car entry prohibited area such as a railroad crossing.

A contour measuring apparatus according to a tenth aspect of the present invention is equipped with second to seventh beam sweeping radar apparatuses, and measures an object contour in a predetermined measurement area.

The contour measuring device is used, for example, for measuring the shape of a building or the like.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. Before describing the specific application of the algorithm, FIG. 1 is a diagram illustrating a yz relationship and an xz relationship. The present algorithm will be described with a higher concept. Given that y = f (x), for example, a data string g (x) in a case where a light beam is emitted in the r direction at equal angular intervals in the θ direction to collect r data for each θ, for example. For each y in the yz region corresponding to each x, the width 2 ×
A median filter of ΔY (ΔY is a wing length) is applied to obtain an output value h * (y) in the yz region, and g * (x) corresponding to the h * (y) (where g
* (X) = h * (y). ). FIG. 2 is a first explanatory diagram for explaining the relational expressions, and the expressions (1) to (5) are satisfied.

FIG. 3 is a second explanatory diagram for explaining the relational expression. Both wings at y = Y point on z = h (y)
If a median filter of length ΔY is applied, the median value of z of z is a curve, z = h (Y−ΔY),
The value of z when the value of the distribution function H (z) is S / 2, where S is the area surrounded by h (Y + ΔY). FIG.
Equations (6) and (7) are the defining equations for S and H (z).

Therefore, the output value at this time is g * (x) = m
edz, where x = f ^-1 (Y). Here, f ⁻¹ is an inverse conversion formula of f. At this time, the data string g
For (x), a rank filter of wing length M and rank T is applied to x. This is shown by equations (8) to (12) in FIG. (10)
C in the equation is a θ coordinate position at which an output is to be obtained by applying a rank filter on the r-θ polar coordinate plane, that is, a center position of the rank filter. Also, H
(Z) and G (z) satisfy the relationship of equation (13) in FIG. According to (8) to (12), processing is actually performed on the x-axis without performing coordinate conversion.

A specific application of the present algorithm will be described. FIG. 4 is an explanatory diagram of processing of measurement data by the radar device. (A) is an example of distance data on the r-θ polar coordinate plane, and (b) is a result of converting the data of (a) into data on the rl coordinate plane. In FIG. 4A, the laser radar is disposed at the origin of the r-θ polar coordinate, and sweeps the laser light beam in the θ direction while maintaining the θ position at every equal angle dθ in the θ direction (in FIG. The scale is marked.), A laser beam is irradiated in the r direction, and the distance r from the reflected light to the object is measured. This laser radar is of a blinking type, and moves from an initial value θs to an end value θe (provided that θs <θe) in the forward + θ direction, and moves from θe to θs in the return −θ direction. And this is repeated as one cycle.
In the case of going, the laser light beam is irradiated at every θ position at equal angular intervals, and in the case of returning, the method of stopping the irradiation of the laser light beam is performed. Either of the methods can be adopted.

Consider an object having a diameter Sr. As this object exists closer to the origin, the expected angle as the angle between both ends in the θ direction with respect to the origin increases. The length dl of the object portion having the prospective angle dθ on the coordinate plane of (a) is expressed by the following equation (41). dl = r · dθ (41) Next, l is defined by the following equation (42). l = ∫ ₀ ^l r · dθ (42)

In FIG. 4B, the length of each object in the 1 direction is proportional to the actual length. In (b), regarding l,
The scale is written in the l-axis direction by the equal dimension lc, and the scale corresponding to each equal angular interval dθ in FIG. The maximum diameter of the object to be excluded in the measurement area is defined as Sr. For the image of (b),
Applying a median filter of size 2 · ΔL, each l
Calculate the position r.

FIG. 5 is a third explanatory diagram for explaining the relational expression. h (l) is an equation that defines the relationship between l and r in FIG. 4B, where r = h (l), and h ⁻¹ (r) is
This means the inverse transformation of (l). On h (l), l = Lc
If a median filter with both wing lengths ΔL is applied at a point, the median of the median is a curve of h (l), r = h (Lc−ΔL), h (Lc +
The distribution function H (r), where S is the area surrounded by ΔL)
Is the value of r when the value of S becomes S / 2. (5 in FIG. 5)
1) and (52) are the defining expressions of S and H (r), respectively.

Therefore, the output value at this time is g * (θ) = m
edr, then θ = f ⁻¹ (l). However, in equation (55), f ⁻¹ is an inverse transform of f, and f
= ∫ ₀ ^l r · dθ. In the equation (56), g
^-1 is the inverse transform of g, g (θ) = r (θ), and r
(Θ) is the distance to the object position measured from the reflected light of the laser light emitted in the r direction from the laser radar device at the origin at each θ position on the r-θ coordinate plane. At this time, the wing (wi)
ng) It means that a rank filter of length M and rank T is applied. These are shown in (53) to (57) of FIG.
It is shown by the equation. Note that c in the equation (55) is r
-The θ coordinate position at which an output is to be obtained by applying the rank filter on the polar coordinate plane, that is, the center position of the rank filter. Further, between H (r) and G (r), there is a relationship of equation (58) in FIG. (51) ~
According to (57), processing is actually performed on the θ axis without performing coordinate conversion.

Consider what happens when the median filter is applied to FIG. 4B in FIG. 4A. The following equation (43) is used to inversely convert the image of the rl coordinate into the image of the r-θ polar coordinate. dθ = (1 / r) · dl (43)

In the median filter of FIG. 4B, wings in the right direction (+ direction of l) and left direction (− direction of 1) with respect to the filter center Lc are called a right wing and a left wing, respectively, and the wing length ± ΔL
When these wings on the rl coordinate plane are converted into lengths Rw and Lw in the θ direction on the r-θ polar coordinate plane, the wings are as shown in equation (53) of FIG. Note that c in equation (55)
Is the center position of the adaptive rank filter applied to the r-θ polar coordinate plane. The size M and rank T of the adaptive rank filter are defined by equations (54) and (57), respectively.

That is, in the coordinate plane of FIG.
The r at each scale position in the θ direction is calculated by an adaptive rank filter of size M and rank T. More specifically, this adaptive rank filter has wings of Rw in the + θ direction and Lw in the -θ direction with each θ position as a reference position,
The size is M in (54) of FIG. 5, and the rank is (57) in FIG. Since ΔL is set so as to correspond to the dimension Sr of the largest object to be excluded from the measurement target object in the measurement area, a medr is obtained for each θ in the r-θ polar coordinate plane, and this is determined as the object position in the measurement area. By using the information, it is possible to obtain the position information of the remaining object after removing the object of Sr or less from the measurement area.

FIG. 6 shows an example of the processing result. The image expressing the distance to the object based on the reflected light at each θ position while sweeping the laser light beam from the laser radar in the θ direction becomes the original image in FIG. The original image of (a) is a median filter (this median filter is different from the above-mentioned adaptive rank filter in that Rw and Lw are fixed irrespective of the θ position, and the rank is also fixed to the median. The image after the processing in () is (b). On the other hand, the image after processing the original image of (a) by the above-mentioned adaptive rank filter of size M and rank T becomes (c). It can be seen that the image in (c) has more accurate removal of unnecessary objects than the image in (b). Further, (b)
The maximum value filter is applied to a total of three frames, i.e., the first frame and the first frame and the second frame in the past in the time axis direction with respect to the reference frame, that is, three frames for r at each θ position The image in which the largest r among the above r is set to r at each θ position at the reference time is the image of the time series processing of (d). It can be seen that the image in (d) has clearer removal of unnecessary objects than the image in (c).

A radar apparatus that performs such an adaptive rank filter process monitors an intrusion of a person or an automobile into an autonomous vehicle that automatically travels while detecting an obstacle in front, a railway crossing or the like, and a restricted area. It is equipped and used in area monitoring devices and shape measuring devices such as buildings.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a yz relationship and an xz relationship.

FIG. 2 is a first explanatory diagram illustrating a relational expression.

FIG. 3 is a second explanatory diagram illustrating a relational expression.

FIG. 4 is an explanatory diagram of processing of measurement data by the radar device.

FIG. 5 is a third explanatory diagram illustrating a relational expression.

FIG. 6 is a diagram illustrating an example of a processing result.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J070 AC02 AC11 AE20 AF02 AH50 AK13 5J083 AA02 AB13 AC29 AD04 AD15 AE10 AF04 BD02 BE60 5J084 AA05 AA10 AA14 AB17 AB20 AC02 BA03 CA22 CA26 CA65 EA02 EA22 FA01

Claims (10)

[Claims] 1. A predetermined measurement area is defined by a polar coordinate plane of r-θ having an origin at a position of a beam sweep type radar, and a beam radiated from the beam sweep type radar in an r direction is swept in a θ direction. , The distance from the reflected beam from the beam reflecting object to the beam reflecting object at each θ position is r (θ)
In the beam sweeping radar device, the dimensions of each reflecting object are obtained based on r (θ) and the range of θ in which substantially the same r (θ) is maintained in the θ direction. When it is determined that the dimension is not more than the predetermined value, the distance at each θ within the range of θ of the reflecting object is changed to r (θ) related to θ before and after the reflecting object in the θ direction, A beam sweeping type radar apparatus characterized by collecting object position information of a measurement area. 2. A predetermined measurement area is defined by a polar coordinate plane of r-θ having an origin at a position of the beam sweep type radar, and a beam radiated from the beam sweep type radar in the r direction is swept in the θ direction. , The distance from the reflected beam from the beam reflecting object to the beam reflecting object at each θ position is r (θ)
In a beam-sweep type radar apparatus which measures as, the r-θ polar coordinate plane is converted to the rl coordinate plane l = f (θ)
Is defined by the conversion of f (θ).
(Θ) is r (l) on the rl coordinate plane. For any point Q on r (l) on the rl coordinate plane (the l coordinate of this Q is Lc), ± direction
Considering the range of ΔL (ΔL is a constant), ∫− _ΔL ^l r (l) · dl = (１ ／) · ∫ _Lc−ΔL
^L that satisfies the condition of ^{Lc + ΔL} r (l) · dl is medl
Θc where Lc = f (θc) and medl = f (θm)
And θm are related to each other by a relation A. The distance re (θ) to the measured object at each θ in the polar coordinate plane of r−θ is represented by r for θm related to the θ in the relation A with θ as θc. (Θm), that is, re (θ) = r (θm) (where θm
Is related to θ by a relation A when θ = θc. ), Re (θ) as object position information of the measurement area. 3. Assuming that 1 = f (θ), f (θ) is ∫ ₀ ^l
3. The beam sweep type radar device according to claim 2, wherein r.d.theta. 4. When the maximum dimension of an object to be excluded from a measurement target object in a measurement area is Sr, the ΔL is
4. The beam sweep type radar device according to claim 3, wherein the amount corresponds to Sr. 5. Points P and r on r (θ) on an r-θ polar coordinate plane
Assume that a point Q on r (l) on the -l coordinate plane is related by f (θ), the θ coordinate of P is θp, the l coordinate of Q is lq, and re (θ) is r ( θ) is processed by an adaptive rank filter. The adaptive filter has a size of Rw + Lw when a center value is θp, and Rw and Lw are Q in r (l). Is the length corresponding to ± ΔL in the l direction, and the rank T is Lc = 1q, that is, θc = θp, and θm related to the θc by the relation A is obtained. 5. The beam sweep type radar apparatus according to claim 4, wherein a medl corresponding to the following equation is obtained, and is obtained from an equation using the medl: T = _∫medl ^{Lc + ΔL} r · dθ. 6. The method according to claim 2, wherein an object measurement image in a measurement area (hereinafter, referred to as a “first image”) is generated based on re (θ). Beam sweep type radar device. 7. A frame in which a first image is defined as one screen is generated at discrete time intervals, and a plurality of frames within a predetermined time including the first frame at time t1 are subjected to a maximum value filtering process to perform frame filtering. The beam sweep type radar apparatus according to claim 6, wherein (hereinafter, referred to as "second frame") is generated, and the second frame is presented as a frame at time t1. 8. A moving body equipped with the beam sweeping radar device according to claim 2 and detecting an obstacle ahead in the moving direction. 9. An object detection device in a fixed measurement area, comprising the beam sweeping radar device according to claim 2 and detecting an object in the fixed measurement area. 10. A contour measuring device equipped with the beam sweeping radar device according to claim 2, which measures an object contour in a predetermined measurement area.