JPH06194447A - Vehicle-mount type laser alarm device - Google Patents

Abstract

PURPOSE:To detect a forward obstacle rapidly and with a high S/N ratio in a vehicle-mount type laser alarm device for monitoring the forward obstacle. CONSTITUTION:Pulse laser beams which are output from a pulse laser oscillator 11 of a transmission part 1 are transmitted via a transmission optical system 12 and form forward irradiation visual field including light-transmission visual field regions (a)-(n). The reflection light due to a forward obstacle appearing at the light-transmission visual field region is received corresponding to either distance of a pin photodiode with improved response constituting a pin photodiode array 22 via a light-reception optical system 21 and is amplified and output for each pin photodiode by an amplifier 23. A distance verifier 32 of a signal processing part 3 with a CPU 30 reads out distance information corresponding to a light-reception pin photodiode, the time lapse tendency of the distance information is judged by an obstacle tendency judging equipment 33, the proximity and separation to and from the obstacle are judged, and the an alarm is output from an alarm display 34 as needed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted laser alarm device, and in particular, irradiates a pulsed laser beam forward in the traveling direction and receives light reflected by an obstacle ahead to recognize the obstacle, and if necessary, The present invention relates to a vehicle-mounted laser alarm device that issues an alarm.

[0002]

2. Description of the Related Art Conventionally, this kind of obstacle recognition and alarm is
The CW laser light or the output light from a light emitting diode is used for transmission, and the reception diode is arranged for reception by arranging a positioning diode on an optical axis different from the transmission optical axis to know the position of the obstacle.

FIG. 4 is a block diagram showing a typical example of a conventional vehicle-mounted laser alarm device.

In FIG. 4, the laser oscillator 101 is a CW.
A transmission laser beam of a type is generated to illuminate the obstacle P via the transmission optical system 102.

The light reflected by the obstacle P is received by the positioning diode 104 via the receiving optical system 103 arranged on an optical axis different from the optical axis of the transmitting laser light.

The positioning diode 104 has X,
It has three output terminals of Y and G (ground), and the output ratio of the X and Y terminals shows a value corresponding to the position of the obstacle P.

X, Y of the positioning diode 104
The terminal outputs are supplied to the amplifiers 105a and 105b, respectively, and output to the difference calculator 106 after amplification.

The difference calculator 106 calculates the difference between the input X and Y terminal outputs and sends it to the position calculator 107.

The position calculator 107 calculates the position of each constituent element of the transmission system and the reception system based on the geometrical conditions and operational conditions.
Position data of obstacle P and positioning diode 10
Correspondingly stored with the output difference data of the X and Y terminals of 4,
Thus, the position of the obstacle P is determined based on the output of the difference calculator 106.

[0010]

The conventional vehicle-mounted laser alarm device described above utilizes a positioning diode for receiving reflected light. Since this positioning diode has a high internal resistance and low responsiveness and is not suitable for pulse reception, the transmission light source covers this low responsiveness as a continuous wave.

For this reason, the transmission power is much lower than the pulse and the received signal is also small, so that it is difficult to extract the signal component by irradiation for a short time, and the received signal is integrated and averaged to obtain S / N. However, there is a problem that the real-time property of signal component extraction is lacking due to the improved reception.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a vehicle-mounted laser alarm device capable of significantly speeding up extraction of a received signal component.

[0013]

A vehicle-mounted laser alarm device according to the present invention includes a transmitter for irradiating a pulsed laser beam forward, and a forward obstacle to the transmitter for reflected light of an obstacle ahead of the pulsed laser beam. A reception unit that separately receives corresponding to the position of an object, and a distance to the front obstacle based on the classification reception output of the reception unit, and a collision with the front obstacle based on the passage of time of the distance. And a signal processing unit for issuing an alarm by judging the danger of.

Further, the vehicle-mounted laser alarm device of the present invention is characterized by the above-mentioned separated reception based on the input light reception of each light receiving element of the light receiving array in which the light receiving elements excellent in response to the pulsed laser light are linearly arranged. It has a configuration that ensures the distance grasp of the front obstacle.

Further, in the vehicle-mounted laser alarm device of the present invention, the laser light received by each light receiving element forming the light receiving array is based on the geometric condition of the transmission / reception field of view formed by the transmitter and the receiver. The distance from the transmitting unit to the front obstacle is calculated in advance for each of them, stored in the signal processing unit, and the distance is obtained by reading the input light receiving element of the light receiving array as an address.

In the vehicle-mounted laser alarm device according to the present invention, the time course of the distance in the signal processing unit is
The configuration includes the proximity and separation of the front obstacle obtained based on the transition state of the light receiving element for receiving the reflected light in the light receiving array and the relative speed thereof.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the embodiment shown in FIG. 1, a transmitter 1 for irradiating a pulsed laser beam forward and a reception for separately receiving reflected light of an obstacle of the pulsed laser light by the transmitter 1 corresponding to the position of the obstacle. The configuration includes a unit 2 and a signal processing unit 3 that determines the distance to an obstacle based on the reception output of the receiving unit 2 and determines the risk of collision with the obstacle.

Prior to the description of the operation of this embodiment, the basic features of the present invention will be described with reference to the principle diagram of FIG.

As shown in FIG. 2, the pulse laser oscillator 10
1 outputs a pulsed laser light, and this output light is a pulsed laser light 1 given a predetermined light transmission characteristic by the transmission optical system 102.
Sent as 03.

On the other hand, in the light receiving system, reflected light is received by the light receiving array 105 via the light receiving optical system 104 arranged on the light receiving axis in a direction different from the light transmitting axis.

In the light receiving array 105, light receiving elements a to n having a very low internal resistance and an extremely high response such as a pin photodiode are arranged on a straight line, and the light receiving optical system 10 is provided.
In combination with No. 4, it is set so that the reflected light from the light-transmitting visual field regions (a) to (n) is separately received by the light receiving elements a to n corresponding to the distance.

From the geometrical arrangement conditions of the entire transmission / reception optical system and the operating conditions such as the transmission / reception level, the light transmission visual field region (a) ...
The position (distance, direction) of (n) is known in advance including the occupied width, and the distance of the obstacle can be grasped based on the collation of this known information and the light receiving element position. Based on the increasing or decreasing tendency of the distance information of the obstacle thus obtained over time, the distance and approach tendency to the obstacle are known, and the degree of danger is determined.

FIG. 3A shows a state in which the obstacle is in the proximity state, and therefore the light receiving position transits from the light receiving element a to n. In this case, the proximity speed depends on θ1, that is, the relative speed to the obstacle.

FIG. 3B shows a transition state when the obstacle is in the separated state.

Returning to FIG. 1, the operation of the embodiment will be described.

The transmitting section 1 outputs a pulsed laser beam having a constant intensity from the pulsed laser oscillator 11 and irradiates the light-transmitting visual field regions (a) to (n) ahead of the traveling direction via the transmission optical system 12.

The light reflected by the obstacles from the light-transmitting visual field regions (a) to (n) passes through the receiving optical system 21 of the receiving section 2 and interferes with the pin photodiode array 22 which is linearly arranged with the pin photodiodes as the light receiving elements. The light is collected by one of the light receiving elements corresponding to the position of the object, amplified by the amplifier 23, and sent to the signal processing unit 3.

The amplifier 23 is provided with an amplifying element corresponding to each pin photodiode constituting the pin photodiode array 22, and it is possible to know which pin photodiode receives the light output.

The signal processing unit 3 addresses the respective pin photodiodes of the pin photodiode array 22 with the CPU 30 which incorporates a program and controls the entire operation, and the distance information to the known light transmitting visual field regions (a) to (n) in advance. And a distance collator 32 that obtains information designating each pin photodiode of the pin photodiode array 22 received by the receiver 2 from the amplifier 23 and reads the distance to the obstacle from the stored data of the ROM 31, and the distance collator The risk of collision is determined as follows by providing an alarm display 34 that issues an alarm based on the output of the obstacle trend determiner 33 that determines the risk of collision based on the time-series trend of the output of the device 32. And make a quick decision in real time.

The distance collator 32 confirms which pin photodiode is received by receiving the output from the amplifier 32, reads the distance data stored from the ROM 31 in correspondence with the pin photodiode, and determines the distance to the obstacle. know.

The obstacle trend determiner 33 is a distance collator 32.
The time history of the distance information output by is obtained as shown in FIG. 3 each time the pulsed laser beam is transmitted, and the relative speed based on the temporal change rate of the distance to the obstacle and the distance based on the temporal increase or decrease tendency of the distance. Alternatively, if the state of proximity is known and the risk of collision is determined, an alarm is issued on the alarm display 34, thus enabling a rapid alarm output in real time.

In the above-mentioned embodiment, the light receiving array in which the pin photodiodes are linearly arranged is used. However, other light receiving elements having a response equal to or higher than that of the pin photodiodes can be used, and the light receiving elements can be used. Obviously, an integrated structure of the array and the output amplifier can be easily implemented.

The obstacle may be a mobile type or a fixed type, and all of the above can be easily implemented without impairing the gist of the present invention.

[0036]

As described above, according to the present invention, the pulsed laser light and the light receiving array in which the high-responsiveness light receiving elements are directly arranged are combined, and the laser light irradiation area is made to correspond to the distance from the transmission position. By separately receiving each of the light receiving elements of the configuration and checking the time course of the obstacle while comparing it with the distance stored in advance corresponding to each light receiving element, the trend of the obstacle can be obtained in real time and with a high S / N. Knowing that, there is an effect that the danger can be detected quickly.

[Brief description of drawings]

FIG. 1 is a block diagram of a vehicle-mounted laser alarm device according to an embodiment of the present invention.

FIG. 2 is a principle diagram showing basic features of the present invention.

FIG. 3 is an explanatory diagram of a case where the time history of an obstacle indicates proximity (a) and a case where the obstacle history indicates separation (b) according to the present invention.

FIG. 4 is a block diagram of a conventional vehicle-mounted laser alarm device.

[Explanation of symbols]

 1 Transmitter 2 Receiver 3 Signal Processor 11 Pulse Laser Oscillator 12 Transmitter Optical System 21 Receiver Optical System 22 Pin Photodiode Array 23 Amplifier 30 CPU 31 ROM 32 Distance Collator 33 Obstacle Trend Judge 34 Alarm Indicator

Claims (4)

[Claims] 1. A transmitter that irradiates a pulsed laser beam forward, a receiver that separately receives reflected light of the pulsed laser beam from an obstacle ahead of the transmitter, corresponding to the position of the obstacle ahead of the transmitter. A signal processing unit that determines a distance to the front obstacle based on the classification reception output of the reception unit, and determines the risk of collision with the front obstacle based on a lapse of time of the distance, and outputs an alarm. A vehicle-mounted laser alarm device comprising: 2. A method for ensuring the distance grasp of the front obstacle by the separate reception based on the input light reception of each light receiving element of a light receiving array in which light receiving elements having excellent responsiveness to pulsed laser light are linearly arranged. The vehicle-mounted laser alarm device according to claim 1, wherein: 3. The obstacle ahead of the transmitting unit for each of the laser beams received by the respective light receiving elements forming the light receiving array based on the geometric condition of the transmission / reception field of view formed by the transmitting unit and the receiving unit. 2. The vehicle-mounted laser alarm device according to claim 1, wherein the distance to is previously calculated and stored in the signal processing unit, and the distance is calculated by reading the input light receiving element of the light receiving array as an address. . 4. The approach and separation of the front obstacle and its relative speed, which are obtained based on the transition state of the light receiving element of the reflected light receiving in the light receiving array, for the time course of the distance in the signal processing unit. The vehicle-mounted laser alarm device according to claim 1, wherein the laser alarm device comprises: