JP2001195700A - Device for detecting vehicle information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle information detecting device by which a near distance is measured at a low cost. SOLUTION: The device is provided with a camera 1 for obtaining the image of the circumference of a self vehicle, a vehicle recognizing means 3 for detecting the existence of the vehicle in its circumference from the image obtained by the camera 1, an ultrasonic sensor 2 for measuring the distance to an target object in the front direction of the camera 1 to generate ranging data and an inter-vehicle distance measuring means 4 for outputting the ranging data when it is judged that the vehicle exists in the visual field of the camera 1 by the output of the means 3. The ultrasonic sensor is used in place of a laser radar or a millimeter wave radar so that the near distance is especially easily measured at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle information detecting device mounted on an automobile, for example, for detecting a vehicle and measuring a distance between vehicles for the purpose of maintaining the distance between vehicles or preventing collision.
In particular, the present invention relates to a vehicle information detection device suitable for use in a system such as a traffic cruise where proximity distance measurement is important.

[0002]

2. Description of the Related Art Conventional techniques are described in, for example,
A number of applications such as No. 6507 have been filed. Hereinafter, a conventional vehicle information detecting device will be described with reference to FIG.

The conventional vehicle information detecting device shown in FIG. 7 includes a camera 51, a millimeter wave radar 52, a vehicle recognizing means 53, and an inter-vehicle distance detecting means 54. The camera 51 captures an image of a certain direction around a vehicle (hereinafter, referred to as an own vehicle) on which the camera 51 is mounted, for example, a situation in front, behind, or side. The millimeter wave radar 52 is a millimeter wave (30 GHz)
電波 100 GHz) is transmitted, and the relative distance from the vehicle to the target is measured based on the time difference from the received wave reflected and returned by the target vehicle. In addition, it is also possible to substitute a radar using a radio wave of a frequency other than the millimeter wave or a laser. The vehicle recognition means 53 detects the presence or absence of a vehicle from the video of the camera 51. Only when the vehicle recognizing unit 53 determines that the vehicle is present in the field of view of the camera 51, the inter-vehicle distance measuring unit 54 outputs the relative distance measured by the millimeter wave radar 52 as distance data to the detection target.

[0004] With the above configuration, the vehicle ahead of the host vehicle can be clearly recognized, and the relative distance from the host vehicle to the target vehicle can be accurately obtained within a certain distance.

[0005]

However, in the above-mentioned conventional vehicle information detecting device, since the millimeter wave radar or the laser radar is used as the distance sensor, the propagation speed is the speed of light, and the distance to the target is small. If is near,
There has been a problem that the detection of the time difference between the transmitted wave and the received wave is actually very difficult, or the device configuration is very expensive even if it can be measured, which makes it particularly difficult to measure a short distance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a vehicle information detecting device capable of realizing short-distance measurement at low cost.

[0007]

According to the present invention, there is provided a vehicle information detecting apparatus for detecting an image of an area around a host vehicle from an image obtained by the image capturing section. Vehicle recognition means, an ultrasonic sensor for measuring distance to a target object in front of the imaging means and generating distance measurement data, and a vehicle in a field of view of the imaging means from an output of the vehicle recognition means. An inter-vehicle distance measuring means for outputting inter-vehicle distance data based on the distance measurement data when it is determined that the vehicle is present. With this configuration, measurement at a particularly short distance can be easily realized at low cost.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a vehicle information detecting device according to a first embodiment of the present invention. This vehicle information detecting device includes a camera 1, an ultrasonic sensor 2, a vehicle recognizing unit 3, and an inter-vehicle distance measuring unit 4.

The camera 1 captures an image of a certain direction around the own vehicle, for example, forward, backward or side, captures the situation as an image, and sends the image to the vehicle recognizing means 3.
The ultrasonic sensor 2 transmits an ultrasonic wave of, for example, 40 kHz to 80 kHz in a pulsed manner, receives a reflected signal of the transmitted pulse reflected on the target, and generates time difference data or distance data to the target. It is sent to the following distance detecting means 4. The vehicle recognizing means 3 detects the presence or absence of a vehicle in the visual field from the image of the camera 1 and sends the result to the inter-vehicle distance measuring means 4 as a vehicle detection output. The inter-vehicle distance measuring means 4 outputs inter-vehicle distance data as data of a detection target only when the vehicle detection output indicates the presence of a vehicle.

The operation of the vehicle information detecting device configured as described above will be described. Here, it is assumed that the camera 1 is set to capture an image in front of the own vehicle. The camera 1 captures an image of the front of the own vehicle and sends an image signal of the captured image to the vehicle recognition means 3. Further, the ultrasonic sensor 2 receives the reflected wave after transmitting the ultrasonic pulse to the front of the own vehicle. When a received wave having a level equal to or higher than a predetermined threshold is detected, a time difference ΔT between the transmission time of the ultrasonic pulse and the reception time of the received wave is measured. Here, the sound speed is u
Then, the distance d to the target can be obtained from d = u × (ΔT / 2) Equation (1). The ultrasonic sensor 2 sends the time difference ΔT or the distance d to the inter-vehicle distance measuring means 4. The vehicle recognizing means 3 detects from the image of the camera 1 whether or not there is a vehicle in the field of view of the camera 1 and sends the detection result to the inter-vehicle distance measuring means 4 as a vehicle detection output. The inter-vehicle distance measuring means 4 outputs distance data of the target based on the time difference ΔT or the distance d sent from the ultrasonic sensor 2 only when the vehicle detection output indicates the presence of the vehicle. That is, when the time difference ΔT is sent from the ultrasonic sensor 2, the distance d is obtained and output by the equation [1], and when the distance d is sent from the ultrasonic sensor 2, it is output as it is.

Here, the measurement by the conventional millimeter wave radar or laser radar and the measurement by the ultrasonic sensor according to the present embodiment will be compared. Millimeter waves and lasers have the speed of light (3 × 10
⁸ m / s), whereas ultrasonic waves travel at the speed of sound (approximately 3
(40 m / s). For example, the propagation time corresponding to a distance of 10 m is 66 ns for the speed of light and 29 for the speed of sound.
ms, and especially at short distances, time measurement using ultrasonic waves can be easily measured with a cheaper circuit configuration, and the resolution is increased.

Note that the ultrasonic sensor 2 is usually 10 m to 2 m.
Although it is good at measurement of about 0 m, it is weak to a distant measurement because it uses the air propagation of sound, so it may be configured to also be used as a conventional millimeter wave radar or laser radar. Further, the relative speed of the vehicle can be measured from the Doppler shift between the transmission frequency of the ultrasonic wave and the frequency of the reflected wave.

As described above, according to the first embodiment of the present invention, it is possible to provide an excellent vehicle information detecting device having an effect of easily and effectively realizing measurement of a short distance between vehicles. it can.

(Second Embodiment) A vehicle information detecting device according to a second embodiment of the present invention is configured to correct the value of the speed of sound used for measuring the distance between vehicles according to the temperature of the outside air.

FIG. 2 is a block diagram showing a configuration of a vehicle information detecting device according to a second embodiment of the present invention. In this figure, the same or corresponding components as those in FIG. 1 are denoted by the same reference numerals as those used in FIG. 1 (the same applies to the following embodiments).

The vehicle information detecting device includes a camera 1, an ultrasonic sensor 2, a vehicle recognizing means 3, an inter-vehicle distance measuring means 4, a temperature sensor 5, and an ultrasonic sensor correcting means 6. Here, the configurations and functions of the camera 1, the vehicle recognizing unit 3, and the inter-vehicle distance detecting unit 4 are the same as those in the first embodiment.

The temperature sensor 5 detects the temperature of the outside air and sends it to the ultrasonic sensor correcting means 6. The temperature sensor 5 needs to be installed at a location away from the range in which the heat of the engine propagates, so that the temperature of the air that has risen due to the heat of the engine is not erroneously detected. Ultrasonic sensor correction means 6
Calculates the temperature-corrected sound velocity according to the output of the temperature sensor 5 and corrects the distance measurement data of the ultrasonic sensor 2.

In the vehicle information detecting device having the above configuration, the ultrasonic sensor 2 transmits an ultrasonic pulse to the front of the own vehicle and then receives a reflected wave. When a received wave having a level equal to or higher than a predetermined threshold is detected, a time difference ΔT between the transmission time of the ultrasonic pulse and the reception time of the received wave is measured. Then, the distance d is calculated using the aforementioned equation [1].

By the way, the equation [1] is used for calculation.
It is known that the propagation speed u of the ultrasonic wave in the air changes as in the following equation [2] depending on the temperature t. u = 331.45 + 0.607t Equation [2] (Source: Know-how of using transistor technology special sensor application circuit, CQ Publishing Co.)

Then, the temperature of the outside air is detected by the temperature sensor 5, and the ultrasonic sensor correcting means 6 obtains the temperature-corrected current accurate sound velocity based on the temperature t and the equation [2]. Find the distance to the target. As a method of correction, when the ultrasonic sensor 2 calculates the distance using the provisional sound velocity value Upre, the ratio Utrue to the correct sound velocity is calculated.
/ Upre may be corrected by multiplying by the distance which is the output of the ultrasonic sensor 2, and if the ultrasonic sensor 2 outputs the propagation time until it returns after being reflected by the target, the correct sound velocity Utrue is determined. Just multiply.

As described above, according to the second embodiment of the present invention, by using the ultrasonic sensor temperature-compensated according to the temperature of the outside air, excellent vehicle information detection for accurately measuring the proximity distance can be achieved. An apparatus can be provided.

(Third Embodiment) In a vehicle information detecting apparatus according to a third embodiment of the present invention, an object is not detected by the ultrasonic sensor even though the presence of the vehicle is detected by the vehicle recognizing means. When the level of the reflected signal from the vehicle is equal to or less than a predetermined value, the transmission power of the ultrasonic sensor is increased to increase the probability of receiving the reflected signal.

FIG. 3 is a block diagram showing a configuration of a vehicle information detecting device according to a third embodiment of the present invention. This vehicle information detection device includes a camera 1, an ultrasonic sensor 2, a vehicle recognition unit 3, an inter-vehicle distance measurement unit 4, and a transmission power control unit 7. Here, the configurations and functions of the camera 1 and the inter-vehicle distance detecting means 4 are the same as in the first embodiment. The ultrasonic sensor 2 is different from the first embodiment in that the reception level of the reflected signal is output to the transmission power control means 7 and the transmission power is controlled by the transmission power control means 7. The vehicle recognizing means 3 is different from the first embodiment in that the vehicle recognizing means 3 outputs a vehicle detection signal to a transmission power control means 7.

The transmission power control means 7 receives the reception level of the reflected signal from the ultrasonic sensor 2 and the vehicle detection output of the vehicle recognition means 3. When a signal from the target vehicle cannot be detected by the ultrasonic sensor 2 or the signal itself is extremely small, even though the vehicle recognition unit 3 can detect the presence of the vehicle, the ultrasonic sensor 2 may cause an excessive deterioration due to temporal deterioration or the like. There is a possibility that the desired transmission power is not output from the sound wave sensor 2. Therefore, the transmission power of the ultrasonic sensor 2 is increased to increase the detection probability of the reflected signal by the ultrasonic sensor 2.

As described above, according to the third embodiment of the present invention, even if the ultrasonic sensor 2 deteriorates with time,
By adaptively changing the transmission power, it is possible to provide an excellent vehicle information detection device capable of vehicle detection and inter-vehicle distance measurement.

(Fourth Embodiment) A vehicle information detecting device according to a fourth embodiment of the present invention has the vehicle recognizing means 3 having a function of identifying a vehicle type, and the detected vehicle type is such as a motorcycle. In the case of a small vehicle, the probability that a reflected signal can be received is increased by increasing the transmission power of the ultrasonic sensor.

FIG. 4 is a block diagram showing a configuration of a vehicle information detecting device according to a fourth embodiment of the present invention. This vehicle information detection device includes a camera 1, an ultrasonic sensor 2, a vehicle recognition unit 3, an inter-vehicle distance measurement unit 4, and a transmission power control unit 7. Here, the configurations and functions of the camera 1 and the inter-vehicle distance detecting means 4 are the same as in the first embodiment. The ultrasonic sensor 2 is different from the first embodiment in that the transmission power is controlled by the transmission power control means 7. The vehicle recognizing means 3 has a function of detecting a vehicle type, and outputs the detection result to the transmission power control means 7 as a first function.
This embodiment is different from the embodiment.

The vehicle recognizing means 3 is capable of recognizing, for example, the type of a truck, a car, a van, a motorcycle, etc. from the form of the vehicle in the image taken by the camera 1. Here, there is a difference in the reflection cross-sectional area when ultrasonic waves are reflected between a motorcycle (motorcycle) and a passenger car, or between a passenger car and a truck. . For example, the reflected power of the returning ultrasonic wave in a motorcycle is extremely small as compared with a passenger car. However, if the transmission power is constantly increased in accordance with the two-wheeled vehicle, the reflected power becomes too large when the passenger car is captured, so that the amplitude of the received signal is saturated or the power consumption is increased.

If the vehicle detected by the vehicle recognizing means 3 is estimated to have a weak reflected power of ultrasonic waves, such as a two-wheeled vehicle, the transmission power control means 7 controls the transmission power of the ultrasonic sensor 2 by the transmission power control means 7. When a passenger car or truck is recognized, the transmission power is returned to the original level so that the target vehicle can be clearly detected without discrimination by vehicle type.

As described above, according to the fourth embodiment of the present invention, even if the object is a two-wheeled vehicle, the vehicle can be detected and the distance between vehicles can be measured by adaptively changing the power. A vehicle information detection device can be provided.

(Fifth Embodiment) A vehicle information detecting apparatus according to a fifth embodiment of the present invention is designed to detect an ultrasonic wave when a vehicle cannot be captured temporarily due to rain, fog, or backlight of the sun. The detection of the vehicle and the measurement of the inter-vehicle distance can be continued by the sensor performing the tracking operation.

The block diagram showing the configuration of the vehicle information detecting device according to the fifth embodiment of the present invention is the same as that of the first embodiment.

When a vehicle is detected by the camera 1 and the ultrasonic sensor 2, the inter-vehicle distance can always be measured while the vehicle is present. However, if there is rain, fog, or backlight from the sun, the camera 1 may not be able to capture the vehicle temporarily, and as a result, the vehicle recognizing means 3 may temporarily lose track of the detected vehicle. on the other hand,
Ultrasonic waves have very little attenuation due to moisture and are not affected by sunlight.

Therefore, in this embodiment, even if the image of the vehicle captured by the camera 1 is temporarily interrupted, rain, dew,
The tracking of the vehicle is continued by the ultrasonic sensor 2 whose detection performance in the backlight is hardly deteriorated.

As described above, in the fifth embodiment of the present invention, even if the vehicle cannot be captured by the camera 1 temporarily due to rain, fog, or backlight of the sun, the vehicle is detected by the ultrasonic sensor 2. And an excellent vehicle information detecting device capable of continuing the inter-vehicle distance measurement.

(Sixth Embodiment) A vehicle information detecting apparatus according to a sixth embodiment of the present invention determines the lateral position and attitude of a vehicle from the relationship between the detected vehicle and a white line on the road. Detectable.

FIG. 5 is a block diagram showing a configuration of a vehicle information detecting device according to a sixth embodiment of the present invention. This vehicle information detecting device includes a camera 1, an ultrasonic sensor 2, a vehicle recognizing unit 3, an inter-vehicle distance measuring unit 4, a lateral position detecting unit 9, and a posture detecting unit 10. Here, the configurations and functions of the ultrasonic sensor 2 and the inter-vehicle distance detecting means 4 are the same as those of the first embodiment. First, the camera 1 outputs the photographed image to the lateral position detecting means 9 as well.
This embodiment is different from the embodiment. The vehicle recognizing means 3 differs from the first embodiment in that the vehicle recognizing means 3 also outputs a vehicle detection signal to the lateral position detecting means 9 and the attitude detecting means 10.

The lateral position detecting means 9 receives the vehicle detection output from the vehicle recognizing means 3 and the image from the camera 1. Similarly, the vehicle detection output from the vehicle recognition unit 3 and the image from the camera 1 are also input to the posture detection unit 10.

The camera 1 can detect not only a vehicle but also a white line on a road surface from the image. Therefore, when the vehicle recognizing unit 3 detects another vehicle, the lateral direction detecting unit 9 obtains the position of the target vehicle in the lateral direction (lateral direction) from the positional relationship with the white line. As a result, the behavior of inflow and outflow from a lane such as an interrupt can be clearly grasped. Further, by obtaining the positional relationship between the own vehicle and the camera 1 in advance, the lateral position of the own vehicle with respect to the road can also be obtained.

The attitude detecting means 10 can grasp the behavior of the vehicle in more detail by obtaining the attitude of the vehicle with respect to the road from the angle difference between the direction of the white line and the traveling direction of the vehicle.

As described above, according to the sixth embodiment of the present invention, it is possible to obtain more detailed vehicle information including not only the inter-vehicle distance but also the lateral position and attitude (angle). An inter-vehicle information detection device can be provided.

(Seventh Embodiment) A vehicle information detection apparatus according to a seventh embodiment of the present invention captures the same target with two or more cameras arranged at a fixed distance from each other, The distance to the target vehicle is obtained, and the inter-camera distance value is calibrated using the distance measured by the ultrasonic sensor.

FIG. 6 is a block diagram showing a configuration of a vehicle information detecting device according to a seventh embodiment of the present invention. This vehicle information detecting device includes a camera 1, an ultrasonic sensor 2, a vehicle recognizing unit 3, an inter-vehicle distance measuring unit 4, a stereo distance measuring unit 11, and a stereo distance correcting unit 12. Here, the configurations and functions of the vehicle recognizing unit 3 and the inter-vehicle distance detecting unit 4 are the same as those of the first embodiment. The camera 1 is composed of two or more cameras arranged at a predetermined interval, and differs from the first embodiment in that the images are output to the stereo distance measuring means 11. The ultrasonic sensor 2 differs from the first embodiment in that the ultrasonic sensor 2 also outputs the distance measurement data to the stereo distance measurement correction means 12.

When the same target can be captured by two or more cameras arranged at a certain distance from each other, the distance to the target vehicle is determined from the focal length, the distance between the cameras, and the amount of parallax for the same target. be able to.
Therefore, in the present embodiment, the stereo distance measuring means 11 is provided, and the distance from the camera to the vehicle is obtained. By providing this means, it is possible to determine the distance for each of a plurality of vehicles and determine the relative positional relationship with the own vehicle.

However, for example, if the distance between the cameras changes, an error occurs in the measured distance. Therefore, the distance obtained by the ultrasonic sensor 2 is sent to the stereo distance measuring and correcting means 12, and the stereo distance measuring and correcting means 12 obtains a distance error using the distance obtained by the ultrasonic sensor 2, and conversely sets the distance error in advance. The distance value between the placed cameras is corrected, and the accuracy of the distance obtained by the stereo distance measuring means 11 is improved.

As described above, according to the seventh embodiment of the present invention, vehicle information can be detected with high accuracy not only from an ultrasonic sensor but also from an image of a camera, and a vehicle having an excellent detection probability and excellent performance can be obtained. An information detection device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle information detection device according to first and fifth embodiments of the present invention;

FIG. 2 is a block diagram showing a configuration of a vehicle information detection device according to a second embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration of a vehicle information detection device according to a third embodiment of the present invention;

FIG. 4 is a block diagram illustrating a configuration of a vehicle information detection device according to a fourth embodiment of the present invention;

FIG. 5 is a block diagram showing a configuration of a vehicle information detection device according to a sixth embodiment of the present invention;

FIG. 6 is a block diagram showing a configuration of a vehicle information detection device according to a seventh embodiment of the present invention;

FIG. 7 is a block diagram showing a configuration of a conventional vehicle information detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 Ultrasonic sensor 3 Vehicle recognition means 4 Distance measurement means 5 Temperature sensor 6 Ultrasonic sensor correction means 7 Transmission power control means 9 Lateral direction detection means 10 Attitude detection means 11 Stereo distance measurement means 12 Stereo distance measurement correction means

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2F065 AA03 AA04 BB05 CC11 DD02 FF04 FF05 GG10 JJ15 QQ31 5H180 AA01 CC03 CC04 CC11 CC12 CC15 FF07 LL01 LL04 LL09 5J083 AA02 AB13 AC08 AC31 AD04 AE01 AF05 AG05 BA01 BA01

Claims (7)

[Claims] 1. An imaging means for acquiring an image of the surroundings of a vehicle,
A vehicle recognizing means for detecting the presence or absence of a vehicle around the own vehicle from an image obtained by the image capturing means, and an ultra-computer for measuring distance to a target object in front of the image capturing means and generating distance measurement data A sound wave sensor; and an inter-vehicle distance measuring means for outputting inter-vehicle distance data based on the distance measurement data when it is determined from the output of the vehicle recognizing means that a vehicle is present in the field of view of the imaging means. A vehicle information detection device characterized by the following. 2. The vehicle information detection according to claim 1, further comprising a temperature sensor for measuring a temperature of outside air, and a sound speed correction unit for correcting the distance measurement data according to the measured temperature. apparatus. 3. When the level of a reflected signal from a target vehicle is equal to or less than a predetermined value with the ultrasonic sensor even though the presence of the vehicle is detected by the vehicle recognition means, the ultrasonic wave 3. The vehicle information detection device according to claim 1, wherein the transmission power of the sensor is increased. 4. The apparatus according to claim 1, wherein said vehicle recognition means has a function of recognizing a vehicle type, and sets the transmission power of said ultrasonic sensor according to said recognized vehicle type. Vehicle information detection device. 5. The vehicle according to claim 1, wherein when the vehicle cannot be detected temporarily from the image acquired by the imaging unit, the vehicle is tracked by the ultrasonic sensor. The vehicle information detecting device according to claim 1. 6. A lateral position detecting means for detecting a position in a lateral direction by obtaining a positional relationship between a white line on a road surface and a vehicle from an image obtained by said image capturing means, 6. An attitude detecting means for detecting the attitude of the vehicle with respect to a road by obtaining an angle difference between the white line and the traveling direction of the vehicle from an image, the attitude detecting means comprising: Vehicle information detection device. 7. A plurality of imaging means arranged at predetermined intervals, a stereo ranging means for measuring a distance to a vehicle from parallax of images acquired by the plurality of imaging means, and the ultrasonic sensor 7. The vehicle information detecting device according to claim 1, further comprising: stereo distance correcting means for correcting the distance data based on the distance to the vehicle detected in the step (c).