JPH0792268A - Data processor of laser range finder - Google Patents

Abstract

PURPOSE:To provide a data processor, of laser range finder, which can increase the accuracy of distance measurement. CONSTITUTION:The data processor of laser range finder is provided with a transmission-side detector 1 which detects reference light, with a reception-side detector 2 which detects reflected light and with a gain controller 3 which increases the amplitude of the reflected light detected by the reception-side detector 2, it compares the reference light with the reflected light which is amplified by the gain controller 3, and it computes the distance to a target on the basis of the going and returning time of a laser beam. The data processor is provided with a brightness data converter 6 which converts the intensity of the reflected light detected by the reception-side detector 2 into a brightness value, with a coefficient table 7 in which coefficients for correction are set, correspondingly to the brightness values and with an operation unit 8 which computes a measured distance by using distance data computed on the basis of the going and returning time of the laser beam and by using the factor table 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing device of a laser range finder (laser distance measuring device) used for distance measurement to a target and image recognition.

[0002]

2. Description of the Related Art As shown in FIG. 3, a data processing device of this type of laser range finder compares a phase A of a reference light with which a target is irradiated with a phase B of a reflected light from the target, The round-trip time T of the laser beam, which is the phase difference, is detected, and the distance from the round-trip time T to the target is calculated.

Further, in the above-described data processing device, when the distance to the target is long or the incident angle of the reference light with respect to the target is small, the intensity of the reflected light decreases and the reflected light is reflected as shown by the phantom line in FIG. Since the light becomes the phase b having a small amplitude, the amplitude of the phase b of the reflected light is increased to a phase (B) which is easy to compare with the reference light by the gain controller, and then the round trip time T is detected and converted into the distance. Was doing.

Such a laser range finder data processing device is, for example, the "Latest Defense Technology Taisei" No. 287 issued by R & D Planning in February 1985.
~ 289.

[0005]

In the data processing device of the laser range finder as described above, there is a time lag (delay) in the phase of the amplified reflected light due to the circuit characteristics of the gain controller. Sometimes. This phase shift tends to increase as the output of the gain controller increases. Therefore, especially when the intensity of the reflected light is low, the output of the gain controller is correspondingly increased, resulting in a large error in the measured distance with respect to the actual distance. Improvement was needed to raise it.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a data processing device of a laser range finder capable of improving the accuracy of distance measurement, in view of the above conventional situation. There is.

[0007]

A laser according to the present invention
The data processing device of the range finder increases the amplitude of the reflected light detected by the transmitting side detector that detects the reference light emitted to the target, the receiving side detector that detects the reflected light, and the receiving side detector. In the data processing device of the laser range finder, which has a gain controller and calculates the distance from the round trip time of the laser beam to the target by comparing the reference light and the reflected light amplified by the gain controller, Using a brightness data converter that converts the intensity of the detected reflected light into a brightness value, a coefficient table that sets correction coefficients corresponding to the brightness value, distance data calculated from the round-trip time of the laser beam, and a coefficient table The configuration is provided with an arithmetic unit that calculates the measurement distance, and the above configuration is used as a means for solving the problem.

The correction coefficient in the coefficient table is, for example, the output of the gain controller that increases with a decrease in the intensity of the reflected light, and the phase of the reflected light that increases as the output increases with time. It is based on the relationship with the shift, and is set as a value for correcting the error of the distance data caused by the time shift of the phase.

[0009]

In the data processing device of the laser range finder according to the present invention, when the intensity of the reflected light is small, the output of the gain controller is correspondingly increased, and the reflected light is increased as the output increases. Since the phase shift with time becomes large, the reference data and the reflected light amplified by the gain controller are compared to calculate the distance data from the round trip time of the laser beam to the target, while the brightness data converter The intensity of light is converted into a brightness value, and the distance data error is removed by correcting the distance data in the computing unit using the correction coefficient in the coefficient table corresponding to this brightness value. The measured distance obtained is obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

That is, as shown in FIG. 1, the data processing device of the laser range finder includes a transmitting side detector 1 for detecting the reference light (indicated by phase A) transmitted from the transmitting optical system, and a receiving optical system. The receiving side detector 2 for detecting the reflected light (indicated by the phase b) received by the system, the gain controller 3 for increasing the amplitude of the phase b of the reflected light detected by the receiving side detector 2, and the reference light A comparator 4 for detecting the round-trip time T of the laser beam by comparing the phase A with the phase B of the reflected light amplified by the gain controller 3 is provided.

Further, the data processing device calculates the round trip time T detected by the comparator 4 into the distance data converter 5 for converting it into the distance data Rd of the digital signal, and the intensity of the reflected light detected by the receiving side detector 2. A brightness data converter 6 for converting into a brightness value I of a digital signal is provided, and a brightness value I of reflected light is provided.
Coefficient table 7 in which the correction coefficient K corresponding to
And a calculator 8 for calculating the measured distance R using the distance data Rd and the coefficient table 7.

The coefficient K of the coefficient table 7 is the output of the gain controller 3 that increases with a decrease in the intensity of the reflected light, and the phase B of the reflected light that increases with an increase in the output.
Is a value for correcting the error of the distance data Rd caused by the time shift of the phase B of the reflected light. The relationship between the coefficient K and the brightness value I is represented by a graph as shown in FIG.

Further, in this embodiment, the luminance value I has 8 bits, that is, 256 gradations and a value of 0 to 255.
As shown in (b), the coefficient table 7 includes the correction coefficient K for each luminance value (0 to 255) I based on the previous graph.
Has been set. It should be noted that, when a numerical value for convenience is put in the coefficient table 7 shown in FIG.
Is 2, the coefficient K is “100”, and the coefficient is “0” in the luminance value I of 255 and a range close to it.

In the calculator 8, the distance data Rd and the brightness value I
And the measurement distance R is calculated from the coefficient K. Measuring distance R
Is calculated by the following equation, R = Rd-K (I).

In the above data processing device, the comparator 4 compares the phase A of the reference light detected by the transmission side detector 1 with the phase B of the reflected light amplified by the gain controller 3, and the round trip time of the laser beam is compared. T is calculated, and the distance data converter 5 converts the round-trip time T of the laser beam into the distance data Rd to the target.

At this time, when the intensity of the reflected light is low, that is, when the amplitude of the phase b of the reflected light detected by the receiving side detector 2 is small, the output of the gain controller 3 is increased to compensate for this. As the output increases, the time lag of the phase B of the reflected light increases. Therefore,
The distance data Rd includes an error due to the time shift of the phase B of the reflected light.

Therefore, in the data processing device, the intensity data converter 6 converts the intensity of the reflected light detected by the receiving side detector 2 into the intensity value I, and the distance data Rd and the intensity value I.
By using the correction coefficient K of the coefficient table 7 corresponding to the above, the arithmetic unit 8 performs the arithmetic operation to obtain the measured distance R from which the error of the distance data Rd caused by the time shift of the phase B of the reflected light is removed. In this way, the data processing device can obtain an accurate measurement distance R even when the intensity of reflected light is low.

Further, the above data processing device is used not only for distance measurement with respect to a predetermined target, but also for image recognition using a laser range finder as an input source. In this case, by scanning with a laser beam, an image having, for example, 128 × 64 pixels and a depth of 8 bits is formed. At this time, the above-described data processing is performed for each pixel of the image.

Even when such image recognition is performed, if there is a portion (pixel) in which the intensity of reflected light is low in the scanning range, an error will occur in the distance data, but the brightness of the reflected light By correcting the distance data according to the value, an accurate measurement distance can be obtained for each pixel, and an image with high accuracy as a whole can be obtained.

[0021]

As described above, according to the data processing device of the laser range finder of the present invention, the distance data calculated from the round-trip time of the laser beam is corrected according to the brightness value of the reflected light. Since the measurement distance is obtained with, even if the intensity of the reflected light is small due to the distance to the target or the incident angle of the reference light, it is possible to almost eliminate the error of the measured distance from the actual distance and improve the measurement accuracy. It can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an embodiment of a data processing device of a laser range finder according to the present invention.

FIG. 2 is a graph (a) showing a relationship between a luminance value and a correction coefficient and a diagram (b) showing a coefficient table.

FIG. 3 is a graph for explaining each phase of reference light, reflected light, and reflected light in a state where the intensity is reduced.

[Explanation of symbols]

 1 Transmitter side detector 2 Receiver side detector 3 Gain controller 6 Luminance data converter 7 Coefficient table 8 Operator

Claims (1)

[Claims] 1. A transmission-side detector that detects a reference light with which a target is irradiated, a reception-side detector that detects reflected light, and a gain controller that increases the amplitude of the reflected light detected by the reception-side detector. In the data processing device of the laser range finder, which calculates the distance from the round-trip time of the laser beam to the target by comparing the reference light and the reflected light amplified by the gain controller, the reflected light detected by the receiving side detector A brightness data converter for converting the intensity of the to a brightness value, a coefficient table in which correction coefficients corresponding to the brightness value are set,
A data processing device for a laser range finder, comprising a calculator for calculating a measured distance using distance data calculated from the round-trip time of a laser beam and a coefficient table.