JP2652058B2 - Object detection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an object detection device that detects an object and recognizes the detected object.

Conventional technology Conventionally, as an object detection device used for a visual sensor or the like of a working robot, a reflected wave from an object when a beam is transmitted by an ultrasonic wave or an electric wave is received, the object is detected, and the detected object is detected. Using a radar that measures the distance to an object, an object in a monitoring area is detected based on its positional relationship while scanning a beam.

That is, the object detection device by the beam scanning type,
While obtaining directionality by pulse transmission of a beam with sharp directivity, scanning is performed so as to cover the monitoring area by pulse transmission of multiple beams, and the received data of each time that caused a time delay due to scanning is signal delayed. After the data is sequentially delayed by the circuit so that all data can be obtained in time coincidence, the collected received data is combined by the combining circuit to visualize the object in the monitoring area. Detected.

However, in such a beam scanning type object detection device, on the assumption that no object exists in the beam direction, it is necessary for the reflected wave from the farthest position in the preset monitoring area to be received. The panel transmission of the next beam cannot be performed until a certain time elapses, and there is a problem that it takes time to collect data and lacks real-time properties.

In such a beam scanning type object detection device,
The entire configuration is complicated because a beam scanning unit, a signal delay circuit, a combining circuit, and the like are required.

Therefore, recently, based on the principle of holography, a processor emits ultrasonic waves or radio waves in free space in a pulsed manner, and based on an echo wave received by a receiving device provided with a receiving characteristic covering a monitoring area, according to a processor. 2. Description of the Related Art A holographic radar has been developed which performs predetermined arithmetic processing for analyzing a signal of a received wave to form an image of an object in a monitoring area.

According to the holographic radar, it is possible to quickly collect data in a monitoring area by emitting ultrasonic waves or radio waves once in a panel shape in free space without performing any beam scanning. An object located inside can be detected based on the positional relationship.

FIG. 7 shows a basic configuration example of a holographic radar.

Here, an ultrasonic wave or a radio wave whose energy is not directional is emitted from a transmitter (not shown) in the form of a pulse in free space, and an echo waveform from the monitoring area A on the wave front of the ultrasonic wave is received by the receiving device 6. Is converted into digital data by a signal A / D converter 7 obtained by receiving the data, the data is temporarily stored in a memory 8, and a predetermined arithmetic processing is performed in a processor 9 in accordance with the data stored in the memory 8. Thus, an image in the monitoring area A is formed, and the image is displayed on the display device 10.

In the figure, O1 and O2 indicate objects in the monitoring area A, respectively. Rx indicates a receiving element.

In addition, as an object detection device used for a monitoring sensor of a working robot, etc., it is required that not only an object in a monitoring area be detected with its positional relationship but also that the shape type of the object be recognized. is there.

Therefore, in the related art, the shape type of the object is recognized according to the waveform characteristics (phase characteristics) of the reflected wave which differ depending on the shape type of the object when the transmission wave by the pulse method is applied to the object.

8 to 12 show waveform characteristics of reflected waves from the object O having various shapes. In the figure, TW indicates a transmission wave by a pulse train signal applied to the object O.

Therefore, when taking such an object recognition means,
In order to make the difference in the waveform characteristics of the reflected waves from objects with various shapes remarkable and to accurately recognize the shape and type of the object, it is necessary to narrow the pulse width of the pulse train signal to be transmitted. Has become.

Now, in particular, considering the case of using an ultrasonic type as a transmitter and a receiver, in order to perform transmission and reception of an ultrasonic signal having a narrow pulse width, an ultrasonic transducer as a transmission and reception element is required. Needs to be lowered.

However, when the Q of the ultrasonic transducer is lowered, the transmitted energy of the transmitted and received ultrasonic waves becomes weak.

Therefore, when using an ultrasonic pulse radar to recognize the shape of an object according to the waveform characteristics of the reflected wave when the transmitted wave is applied to the object, the object is actually recognized only at a short distance on the order of tens of centimeters. It cannot be done.

Object The present invention has been made in view of the above points, and is primarily intended to provide an object detection device capable of reliably and accurately identifying the shape and type of an object located relatively far away. To provide.

The present invention also provides a visual sensor for a working robot that quickly detects an object in a surveillance area using a holographic radar ahead of time, and at the same time recognizes the shape and type of the detected object. It is intended to provide an object detection device that is most suitable for the object detection.

Configuration Hereinafter, an embodiment of the present invention will be described in detail.

First, the principle of recognizing the shape type of an object according to the present invention will be described.

The present invention focuses on the fact that the waveform characteristics (phase characteristics) of the reflected wave when a pulsed transmission wave such as an ultrasonic wave or a radio wave is applied to an object are different depending on the shape type of the object. A histogram of the amplitude distribution is created from the received signal that receives the reflected wave when the object is hit, and the object is recognized based on the characteristics of the histogram.

FIGS. 2 to 4 show examples of waveform characteristics of reflected waves from objects of various shapes and histograms of their amplitude distributions.

FIG. 2A shows a waveform characteristic of a reflected wave from a spherical object, and FIG. 2B shows a histogram of the amplitude distribution.

FIG. 3A shows a waveform characteristic of a reflected wave from a columnar object, and FIG. 3B shows a histogram of the amplitude distribution.

FIG. 4A shows a waveform characteristic of a reflected wave from a prismatic object, and FIG. 4B shows a histogram of the amplitude distribution.

Here, when comparing the waveform characteristics of the reflected waves from the objects of each shape, as the object changes from a spherical shape to a cylindrical shape or a prismatic shape, it is as if the pulse train signal was locally subjected to phase modulation. I understand.

In addition, the histogram of the amplitude distribution of the reflected wave from the spherical object shows that it is similar to the Gaussian distribution.

Furthermore, it can be seen that as the curvature of the reflection surface of the transmission wave becomes sharper from a spherical shape to a cylindrical shape or a prismatic shape, the amplitude of the object other than a certain amplitude level is greatly attenuated and the width of the histogram distribution becomes narrower.

 This is understood from the following.

That is, as shown in FIG. 5, when the object O is spherical, the transmission wave TW by the pulse method scatters uniformly when it hits the spherical object O, and the waveform level of the received signal by the reflected wave RW is obtained. Does not change much.

Also, as shown in FIG. 6, when the object O has a prismatic shape, when the transmission wave TW by the pulse method strikes the prismatic object O, the reflection effect at the edge portion is large, and the reflected wave RW As a waveform characteristic of the received signal, the amount of reflection at a certain amplitude level increases.

In this way, by applying the transmission wave by the pulse method to the object, receiving the reflected wave from the object, and obtaining the histogram of the amplitude distribution of the received signal, the shape type of the object is recognized from the characteristics of the obtained histogram. Will be able to

FIG. 1 shows a basic configuration of an object detection device according to the present invention, which is configured based on the principle of object recognition described above.

The transmitter 1 transmits a transmission wave TW based on a pulse signal having a constant width into the air, the receiver 2 receives a reflected wave RW reflected by the transmission wave TW hitting an object O, and a histogram of an amplitude distribution in the received signal. A waveform processing circuit 3 for obtaining the data of the above, a sample data memory 4 in which histogram sample data of the amplitude distribution in the reflected waves from several types of objects are respectively registered in advance, and each sample data registered in the memory 4. An object determination circuit 5 that sequentially compares the data of the histogram output from the waveform processing circuit 3 and determines an object based on the coincidence of the two data.

In the object detection device according to the present invention thus configured, the waveform processing circuit 3 extracts the data of the histogram of the amplitude distribution according to the waveform of the received signal, thereby extracting the characteristics of the shape type of the object O. it can.

Then, the object determination circuit 5 compares the obtained data of the histogram with sample data of the histogram corresponding to the objects of various shapes registered in the memory 4 in advance to easily determine the shape type of the object O. Can be accurately recognized.

When registering the sample data in the memory 4, for example, a learning function is provided under the control of the microcomputer, and the histogram of the amplitude distribution due to the reflected waves from the objects of various shapes is learned and registered in the memory 4. For example, it is possible to widely recognize various kinds of object shapes.

In the present invention, unlike the related art, the shape type of the object O is not directly recognized from the waveform characteristics of the reception signal by the reflected wave RW when the transmission wave TW by the pulse method is applied to the object O. Therefore, it is not necessary to narrow the pulse width of the transmission wave TW in order to make the waveform characteristics of the received signal remarkable.

Therefore, even when the transmitter 1 and the receiver 2 are of the ultrasonic type, it is not necessary to lower the Q of the ultrasonic pendulum as the transmitting and receiving elements, so that the propagation energy of the ultrasonic wave is weak. This makes it possible to transmit and receive signals by ultrasonic waves with sufficient propagation energy.

Therefore, according to the present invention, when the transmitter and the receiver 2 are of the ultrasonic type, it is possible to recognize the shape and type of a distant object in the order of several meters to several tens of meters even in the air. It is possible to do.

In the object detection device according to the present invention, a holographic radar shown in FIG. 7 is provided, and an object in a surveillance area is two-dimensionally or three-dimensionally positioned by the radar. Then, the transmitter 1 shown in FIG. 1 transmits a transmission wave TW by a pulse method to the detected object, and receives the reflected wave RW from the object to recognize the object. It is characterized by being able to do.

As described above, according to the present invention, particularly by using a holographic radar, a target object can be detected quickly and with good positional accuracy, and the shape type of the detected object can be quickly recognized. Can be performed.

Also, the holographic radar does not require any beam scanning means, a signal delay circuit, a signal synthesizing circuit, and the like unlike the beam scanning radar. And miniaturization can be effectively achieved.

Therefore, when the object detection device according to the present invention is used as a visual sensor of a working robot, the method is optimal in terms of the ability to detect an object and taking up little space when mounted on the working robot.

FIG. 13 shows another application example of the object detection device according to the present invention.

Here, the object detection device 12 according to the present invention is mounted on the bottom of the ship 11.
Is attached, and an object on the seabed 13 is detected, and while recognizing the shape and type of each detected object, the pipe 14 buried in the seabed 13 is deeply searched.

It is needless to say that the carrier in the transmission wave TW and the holographic radar is not limited to the ultrasonic wave, but may be an electromagnetic wave.

As described above, in the object detection device according to the present invention, the reflected wave from the object when the transmission wave by the pulse method is transmitted in the air is received, and the data of the histogram of the amplitude distribution in the received signal is obtained. Above, the sample data of the histogram of the amplitude distribution in the reflected waves from several types of objects whose shapes are known in advance are sequentially compared with each other, and the shape type of the object is determined by matching the two data.
It has an excellent advantage that an object existing from a short distance to a relatively long distance can be recognized reliably and with good discrimination.

Also, in particular, in the present invention, a holographic radar is provided, an object in a monitoring area is detected by the radar, and a transmission wave by the pulse method is transmitted toward the detected object to form the object. With the simple configuration, it is possible to quickly detect the object in the monitoring area and at the same time recognize the detected object, such as the visual sensor of the working robot This is advantageous.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration example of an object detection device according to the present invention. FIGS. 2 (a) and 2 (b) show waveform characteristics of a reflected wave from a spherical object and a histogram of its amplitude distribution. 3 (a) and 3 (b) are waveform characteristic diagrams of reflected waves from a cylindrical object and histograms of their amplitude distributions, and FIGS. 4 (a) and (b) are diagrams of reflected waves from a prismatic object. FIG. 5 is a diagram showing the reflection state of a transmission wave on a spherical object, FIG. 6 is a diagram showing the reflection state of a transmission wave on a prismatic object, FIG.
The figure is a block diagram showing a general basic configuration of a holographic radar, and FIGS. 8 (a) and (b) to FIGS. 12 (a) and (b) show a transmission wave by a pulse method on objects of various shapes. FIG. 13 is a diagram showing the applied state and the waveform characteristic of the reflected wave at that time, and FIG. 13 is a diagram showing an application example of the object detection device according to the present invention. 1 ... transmitter, 2 ... receiver, 3 ... waveform processing circuit, 4
…… Sample data memory, 5 …… Object judgment circuit

Claims (2)

(57) [Claims] 1. A transmitter for transmitting a transmission wave in the air by a pulse method, a receiver for receiving a reflected wave of the transmission wave hitting an object, and a waveform processing for obtaining histogram data of an amplitude distribution in the received signal. Means, sample data memory in which sample data of histograms of amplitude distributions in reflected waves from several types of objects whose shapes are known in advance are respectively registered, and each sample data and waveform processing means registered in the memory. An object detection device configured to sequentially compare output histogram data with each other and determine a shape type of the object based on a match between the two data; 2. A holographic radar is provided, an object in a surveillance area is detected by the radar, and a transmission wave by a pulse method is transmitted from the transmitter to the detected object. 2. The object detection device according to claim 1, wherein: