JP4101923B2 - Object detection device - Google Patents

Description

の演算が行なわれる。
【００２５】
このＧＤ［ｊ］（ｊ＝０，１，……，２８）は、図１に示す、測定領域を５０％のオーバラップをもって１００ｍｍごとに分離した２９の領域ＧＤｊ（ｊ＝０，１，……，２８）に対応する信号である。
演算器４０内では（１）の演算を行なった後、最小検出物体幅をＲｍｍとしたとき、しきい値Ｔｈ＝Ｒ／１００を用いて、
【００２６】
【数１】

【００２７】
のしきい値処理を行ない、各領域ＧＤｊに物体が存在する（ＢＤ［ｊ］＝１）か存在しない（ＢＤ［ｊ］＝０）かをあらわす二値信号が生成される。
本実施形態では、このようにして、５０％ずつオーバラップした各領域ＢＤｊ（ｊ＝０，１，……，２９）のそれぞれについて物体の有無が検知され、いずれか１つの領域であっても物体が存在すると検知されたときは、測定領域１０に物体（ここでは車両）が存在する旨判定される。
【００２８】
尚、本実施形態では、車両が存在するか否かを検知する物体検知装置について説明したが、本発明は車両に限らずどのような物体を検知の対象としてもよい。
【００２９】
【発明の効果】
以上説明したように、本発明によれば、物体の有無を高精度に検知することができる。
【図面の簡単な説明】

【符号の説明】
１０ 測定領域
１１ 支柱
１２ 支柱
２０ 発光素子
２１ ＬＥＤドライバ
２２ 投光レンズ
２３ 受光レンズ
２４ 受光素子
２５ プリアンプ
２６ 奇数用マルチプレクサ
２７ 偶数用マルチプレクサ
２８ サンプルホールド回路
２９ 減算器
３０ サンプルホールド回路
３１ サンプルホールド回路
３２ 減算器
３３ サンプルホールド回路
３４ 奇数／偶数切替用のマルチプレクサ
３５ サンプルホールド回路
３６ Ａ／Ｄ変換器
３７，３８ 遮光板
４０ 演算器
５０ タイミングジェネレータ
１００ 車両[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an object detection device that detects whether or not an object exists in a predetermined measurement region where a measured object is expected to pass.
[0002]
[Prior art]
In recent years, non-stop tollgates have been considered as forms of tollgates on highways, where vehicles traveling at high speeds of up to 160 km are separated from each other in order to collect the correct tolls. It is necessary to measure the dimensions and so on.
Here, it is not always easy to reliably recognize one vehicle from another vehicle. Vehicles that pass through the toll gate have various dimensions and shapes, and some of them are divided into a driver's seat part and a cargo bed part like a trailer, and they are connected by a small connecting part. Since it is necessary to recognize that the vehicle is a single vehicle connected by a small connecting portion, it is also necessary to reliably detect the small connecting portion.
[0003]
FIG. 4 is a schematic diagram showing a non-stop toll gate while a vehicle is passing.
FIG. 4 shows a state in which the vehicle 100 passes through a measurement region 10 sandwiched between columns 11 and 12 erected on both sides. Here, a light projecting unit fixed to the column 11 is shown. Whether or not the vehicle is passing through the measurement area is detected based on whether or not light is emitted toward the support column 12 and received by a light receiving unit fixed to the support column 12.
[0004]
Here, it is necessary to surely detect the trailer connecting portion described above, and in order to satisfy this requirement, the light projecting portion and the light receiving portion are arranged at a predetermined pitch in the vertical direction, and even if it is a small object, either It can be considered that detection is possible with a pair of a light projecting unit and a light receiving unit. There are also very small trailer connecting parts. To ensure that even the smallest shape can be detected, the light projecting parts and light receiving parts are arranged at a very fine pitch, for example, at a 100 mm pitch. There is a need to.
[0005]
[Problems to be solved by the invention]
However, even if it is arranged at a pitch of 100 mm, for example, only points every 100 mm can be detected, so the gap between the detection points (heights) is still blank. For example, the vertical dimension when viewed from the side is smaller than 100 mm. When a connection part exists, the connection part is not detected and there is a possibility that it may be recognized as two vehicles.
[0006]
In order to prevent such detection from falling off, the beam diameter of the light projected from the light projecting unit is expanded to cover each region where the measurement region is divided in the height direction (for example, It is conceivable that the beam diameter is expanded to 100 mm when arranged at a pitch of 100 mm. However, considering that the beam diameter of each light projecting portion is simply expanded and the light beam having the expanded beam diameter is collected and received by the light receiving portion corresponding to the light projecting portion, the adjacent two light beams are adjacent to each other. When a small object is located in a minute, both of the two adjacent light receiving units have low sensitivity to the object, and even if the object is of a size that can be detected when positioned at the center of one light beam, There is a possibility that it cannot be detected by being located in the adjacent part of the light receiving unit.
[0007]
In view of the above circumstances, an object of the present invention is to provide an object detection device that can detect an object passing through a measurement region with high accuracy.
[0008]
[Means for Solving the Problems]
The object detection device of the present invention that achieves the above object is
A plurality of light emitting elements arranged in a predetermined arrangement direction;
A light projection lens that collimates the light emitted from each light emitting element by sharing the irradiation of each light projection area in which a predetermined measurement area through which the object to be measured passes is divided into a plurality in a predetermined arrangement direction. A projection optical system;
A plurality of light receiving elements arranged in a predetermined arrangement direction;
A light receiving optical system having a light receiving lens that collects light in each light receiving region arranged in a predetermined arrangement direction so as to include two adjacent light projecting regions and guides it to each light receiving element;
And a signal processing unit configured to detect an object passing through the measurement region based on light reception signals obtained by the plurality of light receiving elements.
[0009]
In the present invention, a beam diameter is determined so that irradiation of each light projecting area is shared by light emitted from each of a plurality of light emitting elements, and each light receiving element includes half of two adjacent light projecting areas. Because it detects the light inside, even if it is a small object, it is prevented from being missed, and it can detect the passage of the object with the same sensitivity no matter where the object passes in the measurement area. it can.
[0010]
Here, in the object detection device of the present invention, two light receiving elements corresponding to two light receiving areas each including one light projecting area corresponding to the light emitting element being turned on are lit while sequentially turning on the plurality of light emitting elements. It is preferable to provide a timing adjustment unit that samples each received signal obtained by the element.
By doing so, the light reception signal obtained due to the light emitted from each light emitting element is separated for each light emitting element, which is substantially the same as when the light emitting elements and the light receiving elements are arranged at a double pitch. The effect of can be obtained.
[0011]
Further, in the object detection device of the present invention, the signal processing unit determines whether or not an object is present based on the light reception signals obtained by the plurality of light receiving elements. It is preferable to detect the above.
The light projecting area and the light receiving area are overlapped by half each other, and by detecting each light projecting area and each light receiving area, it is possible to perform highly accurate detection without omission.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is an overall configuration diagram of an embodiment of an object detection apparatus of the present invention.
In the present embodiment, an LED is employed as the light emitting element 20. Here, the LED is mounted on the column 11 shown in FIG. 4 together with the light projection lens 22 at a predetermined vertical pitch (for example, 100 mm pitch). 16 are arranged. Here, in order to distinguish these 16 LEDs from each other, they are referred to as LED0 to LED15.
[0013]
The light emitted from each LED is collimated by each projection lens 22 provided corresponding to each LED, crosses the measurement region 10 sandwiched between the two columns 11 and 12 shown in FIG. The light is condensed by the lens 23 and enters each light receiving element 24. Here, the light receiving lens 23 includes light receiving regions GD0, GD2,..., Each including half of two adjacent light projecting regions among the light projecting regions GD1, GD3,. One for each GD28. Each light receiving element 24 is arranged at a condensing point by each light receiving lens 23. Here, a PPD (PIN Photo Diode) is adopted as the light receiving element, and this PPD is shown in FIG. It arrange | positions with the predetermined pitch on the support | pillar 12 shown. Here, 15 PPDs are arranged, and these 15 PPDs are referred to as PPD1 to PPD15 in order to distinguish them from each other.
[0014]
FIG. 2 is a detailed view of the optical system in the embodiment shown in FIG. Each projection lens 22 is composed of two cylindrical lenses 221 and 222 having power in directions orthogonal to each other. This is because the LED power is efficiently output to a rectangular region of x << y. Each light receiving lens 23 is composed of one lens having power in both directions.
[0015]
Between each light-receiving lens 23 and each light-receiving element 24 (PPD1, PPD2,...), Two light-shielding plates 37 and 38 are arranged to block the extraneous light from entering. Are formed with openings 37a and 38a through which light emitted from the light emitting element 20 passes.
An optical filter that transmits only light having the emission wavelength of the LED used here is fitted into the opening 38a of the light shielding plate 38 on the side close to the light receiving element 24 of the two light shielding plates 37 and 38. It is.
[0016]
Returning to FIG. 1, the description will be continued.
Each light emitting element 20 sequentially emits light when the LED driver 21 receives a control signal from the timing generator 50.
After each light reception signal obtained by each light receiving element 24 passes through each preamplifier 25, light reception signals obtained by odd-numbered light receiving elements PPD1, PPD3,. The received light signals obtained by the PPD 2, PPD 4,..., PPD 14 which are the second light receiving elements are input to the even multiplexer 27.
[0017]
In the odd multiplexer 26 and the even multiplexer 27, one of the received light signals is sequentially selected in accordance with each control signal from the timing generator 50, and the odd multiplexer 26 and the even multiplexer 27. Is output from.
The light reception signal output from the odd multiplexer 26 is input to the sample hold circuit 28 and the subtractor 29. The sample and hold circuit 2 samples and holds the background signal at the timing when the LED is not lit, and the subtractor 29 subtracts the background signal from the subsequent received light signal. The signal output from the subtracter 29 is sampled and held by the sample hold circuit 30.
[0018]
Similarly, the light reception signal output from the even-number multiplexer 27 is sampled and held by the sample hold circuit 31 at a timing when the LED is not lit, and a background signal is generated by the subtractor 32. The signal is deducted. The output of the subtracter 32 is sampled and held by the sample hold circuit 33.
[0019]
The two signals sampled and held in the two sample hold circuits 30 and 33 in this way are alternately switched by the odd / even multiplexer 34, and the signal output from the multiplexer 34 is another sample hold. It is sampled and held by the circuit 35, converted to digital data by the A / D converter 36, and input to the arithmetic unit 40. In this computing unit 40, it is determined whether or not a vehicle passes through the measurement region 10, and the vehicles passing through the measurement region 10 are separated one by one for signal processing.
[0020]
The timing of each part described above is generated by the timing generator 50 according to the clock signal CLK, and a control signal for controlling the timing is supplied to each part.
FIG. 3 is a timing chart of the embodiment shown in FIG.
An LED on / off signal for controlling the on / off timing of the LED shown in (1) is transmitted from the timing generator 50 to the LED driver 21, and the LED driver 21 responds to the LED on / off signal ( As shown in 2), each LED is turned on sequentially. Each numerical value of “0”, “1”,..., “15” at the timing shown in (2) indicates that the LED corresponding to the numerical value, that is, LED0, LED1,. Show.
[0021]
(3) The odd-number MPX and (4) the even-number MPX indicate the switching timing of the odd-number multiplexer 26 and the even-number multiplexer 27 shown in FIG. 1, and each numerical value “1”, “3”, “5”,..., “15” and “2”, “4”, “6”,..., “24” are light receiving elements corresponding to the numerical values, that is, PPD1, PPD3,. ..., PPD15 and PPD2, PPD4, PPD6,..., PPD14 means that the received light signals are output from the multiplexer.
[0022]
(5) Background S / H and (6) Signal S / H represent the timing of sample and hold by the sample and hold circuits 28 and 31 and the timing of sample and hold by the two sample and hold circuits 30 and 33, respectively. Yes.
(7) The odd-numbered signal and (8) the even-numbered signal represent the signals sampled and held by the sample and hold circuits 30 and 33, respectively, and the codes written there, ie, “1-0”, “ 1-1 ′, “3-2”,..., “15-14”, “15-15”, and “2-1” 2-2 ”,“ 4-3 ”,. Reference numerals 13 'and '14 -14' represent light reception signals obtained by PPDa at the timing when the LEDb is lit when these are representatively represented as 'ab'.
[0023]
(9) Odd / even switching MPX is a switching control signal for the multiplexer 34, and (10) MPX output represents an output signal from the multiplexer 34. (10) The meaning of the code 'ab' entered in the MPX output is the same as described above. The signal indicated by the (10) MPX output is sequentially sampled and held by the sample and hold circuit 35, sequentially AD converted by the A / D converter 36, and input to the computing unit 40. In the arithmetic unit 40, it is determined whether or not a vehicle is present in the measurement area as follows.
[0024]
Here, as shown in FIG. 3, the numbers j = 0, 1, 2, 3,..., 28, 29 are given to the respective timings, and signals at the timings (for example, at the timing of j = 0, '1 −0 ′ signal) is represented by AD [j]. Further, the maximum value of the AD [j] signal updated when no vehicle is present in the measurement region 10 is represented by AD _max [j]. At this time, in the arithmetic unit 40,

Is calculated.
[0025]
This GD [j] (j = 0, 1,..., 28) is 29 regions GDj (j = 0, 1,...) Shown in FIG. 1 in which the measurement regions are separated every 100 mm with 50% overlap. ..., 28).
In the calculator 40, after performing the calculation of (1), when the minimum detected object width is Rmm, the threshold Th = R / 100 is used.
[0026]
[Expression 1]

[0027]
The binary signal indicating whether an object exists in each region GDj (BD [j] = 1) or does not exist (BD [j] = 0) is generated.
In the present embodiment, the presence or absence of an object is detected for each of the regions BDj (j = 0, 1,..., 29) that overlap each other by 50% in this way. When it is detected that an object is present, it is determined that an object (here, a vehicle) is present in the measurement region 10.
[0028]
In the present embodiment, the object detection device that detects whether or not a vehicle is present has been described. However, the present invention is not limited to a vehicle, and any object may be detected.
[0029]
【The invention's effect】
As described above, according to the present invention, the presence or absence of an object can be detected with high accuracy.
[Brief description of the drawings]

[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Measurement area | region 11 support | pillar 12 support | pillar 20 light emitting element 21 LED driver 22 light emitting lens 23 light receiving lens 24 light receiving element 25 preamplifier 26 multiplexer for odd number 27 multiplexer for even number 28 sample hold circuit 29 subtractor 30 sample hold circuit 31 sample hold circuit 32 subtraction Unit 33 Sample hold circuit 34 Multiplexer 35 for odd / even switching Sample hold circuit 36 A / D converters 37 and 38 Light shielding plate 40 Arithmetic unit 50 Timing generator 100 Vehicle

Claims (3)

A plurality of light emitting elements arranged in a predetermined arrangement direction;
A light projection lens that collimates the light emitted from each light emitting element by sharing the irradiation of each light projection area in which a predetermined measurement area through which the object to be measured passes is divided into a plurality in a predetermined arrangement direction. A projection optical system;
A plurality of light receiving elements arranged in a predetermined arrangement direction;
A light receiving optical system having a light receiving lens that collects light in each light receiving region arranged in a predetermined arrangement direction so as to include two adjacent light projecting regions and guides it to each light receiving element;
An object detection apparatus comprising: a signal processing unit configured to detect an object passing through the measurement region based on light reception signals obtained by the plurality of light receiving elements.   While sequentially lighting the plurality of light emitting elements, the reception signals obtained by the two light receiving elements corresponding to the two light receiving areas each including one light projecting area corresponding to the light emitting element being lit are sampled. The object detection apparatus according to claim 1, further comprising a timing adjustment unit.   The signal processing unit is configured to detect whether or not an object is present for each light projecting region and each light receiving region based on light reception signals obtained by the plurality of light receiving elements. The object detection apparatus according to claim 1.

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