JPH0346589A - Distance measuring device - Google Patents

Abstract

PURPOSE:To improve the long distance distance measuring performance, while securing the safety to eyes by adding synchronously a receiving video whenever a laser having low peak power and a high repeat rate is emitted and improving the S/N. CONSTITUTION:A high repeat rate laser transmitter 15 has a repeat rate of about 1Kpps, but on the other hand, its peak power is such low power as about 10kW. In this state, laser video data 17 obtained by bringing a laser video signal 10 reflected by a target to A/D conversion 16 is written if a first memory 18 in a real time at every start pulse 5. Also, before the next emitted pulse, past data of the memory 18 and a second memory 19 are added 22, and stored in the memory 19 again. Subsequently, an (n) field portion is added by the number of times determined by a timing circuit 27, a read-out pulse 26 is outputted to a switching circuit 23 and added data 24 of the memory 19 is inputted to a deciding circuit 25, address data for showing an hourly position of the data exceeding a threshold is detected, and it is outputted as range data.

Description

[Detailed description of the invention] [Industrial application field] This invention ensures eye safety.

The present invention relates to a laser distance measuring device for improving distance measuring ability over long distances.

[Conventional technology]

The fourth factor is an example of the configuration of a conventional laser distance measuring device, in which (1) is a transmission @ optical system, (2) is a laser transmitter, (2A) is a laser oscillator, (2B) ) is the laser pulse power supply, (3) is the transmitted laser beam, (4) is the start pulse detector, (5) is the start pulse, and C6) is the reflected light.

(7) is a receiving optical system, (8) is a photodetector, (9) is an amplifier, an is a laser video signal, aD is a comparator,
ti■ is the stop pulse, a east is the counter, and Q4) is the range data.

In the figure, a pulsed laser beam 9 generated by a laser transmitter (2) is irradiated onto a target by a transmission optical system (1) as a transmission laser beam (3) having a predetermined laser divergence angle.

The reflected light (6) from the target is focused on a photodetector (8) by a receiving optical system (71), converted into an electrical signal, amplified by an amplifier (9), and sent to a comparator aυ as a laser video signal αυ. is input.

- 10,000, at the time when the transmitted laser beam (3) is sent out, a part of the transmitted laser beam (3) is detected by the start pulse detector (4).
) is received, converted into an electrical signal, and then input as a start pulse +51 to the color/rear αJ.
The operation of counter αJ is started. The comparator αυ outputs a stop pulse αa to the counter (3) a3 when the laser video signal αG is greater than a predetermined @ value, and the distance at the target line is calculated from the delay time calculated from the start pulse (51). and the range data force is output.

[Problem to be solved by the invention]

Conventional equipment is configured like this.

In order to maintain distance measurement capability at long distances 1, it is necessary to increase the peak power of the transmitted laser beam (3).

Not only will this cause serious damage to the device, but if there is reflection from nearby buildings, strong reflected laser light will enter your eyes, which can be dangerous. There was a hint of that.

The present invention was made to solve this problem, and it is an object of the present invention to improve long-distance ranging ability without increasing the laser beam power.

[Means to solve the problem]

The present invention includes a high repetition rate laser transmitter and a first device that A/D converts a received laser video signal and stores its output.
and a second memory that stores an addition result of past data in the first memory.

(means for adding the data in the first memory and the data in the second memory and storing the result in the second memory; and after emitting laser pulses a predetermined number of times, Read the memory contents of 2.

Data that exceeds a predetermined threshold is set as a target signal.

The distance data of this signal is used as distance measurement data. In yet another aspect of the invention, after firing the laser pulse a defined number of times.

a threshold circuit for detecting data that exceeds a predetermined threshold 1i1 by extending the second memory content km, and calculating and outputting the position of the center of gravity of the address data of the data that exceeds the threshold 1i1;
This is used as a means of obtaining distance measurement data.

[Effect]

This invention can improve the S/N ratio by emitting a laser with low peak power and high repetition rate and summing the received video every time, ensuring eye safety. It is possible to improve distance measurement performance while traveling far away.

Furthermore, in another aspect of the present invention, when the target consists of a plurality of echoes, the center of gravity of these echoes in the distance direction is calculated, so that the accuracy of distance measurement can be improved.

〔Example〕

FIG. 1 is a diagram showing the configuration of one embodiment of the configuration of the present invention, in which 4 indicates high repetition rate laser transmission m, (
+5A) is a laser diode (LD) excitation laser oscillator, (15B) is a laser power supply, (119 is an A/D
Weird 9! , antrz laser video data, α ladder is the first
memory, (I9 is the second memory, +211 is the first memory driver, 1211 is the second memory driver,
C13 is a switching (b) path, c! 4 is addition data, ■ is a four-way judgment, (1) is a read pulse or timing circuit, and (2) is address data. The second factor is a diagram showing the timing of operations.

Unfortunately, the high repetition rate laser transmitter +19 is a general IC.
Although it has a high repetition rate of about 1 kpps, its peak power is about 10 KW, which is lower than that of conventional YAG pulse lasers in the IMW class. In the first prisoner, the transmitting laser beam (3) is emitted from the transmitting optical system (1) toward the target as in the conventional case. A/D converter aO connects the laser video signal from the target.
The laser video data αD is stored in the first memory U.
The information is input to S in real time. As shown in FIG. 2, the first memory U receives a start pulse (5) and writes input data in real time for each laser emission pulse by the first memory driver (A). The full adder adds the data in the first memory U and the past data in the second memory α until the next laser emission pulse, and stores the result again in the second memory α. do. Nakako's addition is the second
With the memory driver Q11, writing of laser video data to the first memory 08 can generally be performed at a lower speed than real-time writing.

n feel 1 which is the number of times determined by timing circuit 0
When the addition of ♂t is performed, the ♂t overflow pulse ♂ is outputted to the switching circuit, and the addition data C14, which is the addition result stored in the second memory 4, is input to the determination circuit ♂. The judgment circuit ■ detects the addition data (
2) is detected as address data 1281'i in Table (7) and output as gold range data Q4.

Since the addition of the laser video data OD is performed in synchronization with the laser emission pulse as described above, the S/N ratio can be improved by 17 times.

By the way, when the target consists of a single surface, it is possible to accurately measure the target ship distance with the above configuration.9 For example, when the target consists of multiple small groups, Range data must be kept in mind, and it is critical to accurately orient the target.

FIG. 3 shows the partial cost of the configuration of an embodiment according to another invention to solve such difficulties, in which (2) is a threshold value path, (7) is a binarized video, and a circle is This is the center of gravity calculation path. The addition data (2) is input to the − value circuit (2),
The data of the predetermined X1 plane or more is input to the center of gravity depth processing circuit 6° C. as the binarized video ω in state 1. The center of gravity calculation circuit C (11) uses only the address data (2) having the data of state 1 to perform calculations on these positions JKILL? and d', and outputs this as range data α.

(8) [Effects of the Invention] As described above, according to the present invention, since a laser with a low peak power is transmitted at a flat repetition rate and received video is synchronously added, distance measurement performance equivalent to or higher than that of the conventional method can be obtained. Not only can you do this, but you can also greatly improve safety.
It can make a significant contribution to improving operability.

Furthermore, according to another invention of the present invention, since the center of gravity of the distance positions of a plurality of significant received echo pulses is calculated, the distance can be accurately measured even to a target with an unclear outline. It can make a significant contribution to improving the vehicle's performance.

[Brief explanation of drawings]

The first diagram shows the configuration of one embodiment of the configuration of this invention, the second diagram shows the timing of the operation of this invention, and the third diagram shows the configuration of an embodiment according to another invention of this invention. FIG. 4 shows an example of the configuration of this conventional laser distance measuring device. In the figure, (1) is the transmission@optical system, (2) is the laser transmitter, (3) is the transmitted laser beam, (
4) is the start pulse detector, (5) is the start pulse, (6) is the reflected light, (7) is the receiver @ optical system, (8) is the photodetector, (9) is the amplifier, αO is the laser video signal , αυ
is a comparator, a'a is a stop pulse, Q3 is a counter, α4 is range data, α9 is a high repetition rate laser transmitter, (+5A) is a laser diode pumped laser oscillator, (15B) is a laser power supply. Go0 is the A/D converter, αD is the laser video data, α mallet is the first memo! j, '+19 is the second memory, prisoner is the first memory
memory driver, can is the second memory driver ■ is the switching circuit, c! 41 is addition data, ■ is a judgment path, ■ is a read pulse, CI! 71 is timing-road. (To) is the address data, ■ is the threshold circuit, ω is the binarized video, and 611 is the center of gravity calculation IP! It is J road. In the figures, the same reference numerals are given to the same or corresponding parts.

Claims (2)

[Claims] (1) In a distance measuring device that irradiates a target with pulsed laser light and measures the distance to the target from the propagation delay time of the reflected light, a high repetition rate laser transmitter and A/D conversion of the received laser video signal are used. a first memory that stores the output;
a second memory that stores the addition result of past data in the first memory; and a second memory that stores the addition result of past data in the first memory;
means for adding the data in the second memory and storing the result in the second memory again; and after emitting a laser pulse a predetermined number of times, reading out the contents of the second memory and data exceeding a predetermined threshold; What is claimed is: 1. A distance measuring device comprising means for using a target signal as a target signal and using distance data of the signal as ranging data. (2) In a distance measuring device that irradiates a target with a pulsed laser source and measures the distance to the target from the propagation delay time of reflected light, a high repetition rate laser transmitter and A/D conversion of the received laser video signal are used. a first memory that stores the output;
a second memory that stores the addition result of past data in the first memory; and a second memory that stores the addition result of past data in the first memory;
means for adding the data in the second memory and storing the result in the second memory again; and after emitting a laser pulse a predetermined number of times, reading out the contents of the second memory and exceeding a predetermined threshold. 1. A distance measuring device comprising: a threshold circuit for detecting data; and means for calculating and outputting the position of the center of gravity of address data of data exceeding the threshold value to obtain distance measuring data.