JP2003043145A - Shape measuring method and system using laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape measuring method and a system using a laser capable of accurately measuring a shape of a target moving at a high speed. SOLUTION: Delay time is detected between respective reflected signals g1 to gN obtained from the reflected light reflected by striking on the target 14 among projection beams 11 projected from a laser beam source 10A and a reference signal 13 obtained from the reference light of a part of the projection beams 11. The shape of the target 14 is measured by respectively calculating a distance up to the target 14 on the basis of the delay time. The reflected light is received by using a plurality of reflected light receiving elements 16, and the reflected signals g1 to gN are outputted from the respective reflected light receiving elements. The distance is measured in parallel on the respective reflected signals g1 to gN.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring method and system using a laser, and more particularly to a shape measuring method and system using a laser for measuring a target shape moving at high speed.

[0002]

2. Description of the Related Art First, a conventional shape measuring system using a laser will be described with reference to FIGS. Figure 5
FIG. 1 is a schematic diagram showing an example of the shape measurement system. The shape measurement system 200 includes a laser light source 200A and
Reference light receiving element 200B, reflected light receiving element 200C having reflected light receiving element 206, pixel 207, mirror 222 and mirror control circuit 221, and time measuring circuit 200D.
And an arithmetic circuit 200E.

In this shape measuring system 200,
The reflected signal 200g obtained from the received light beam 205 which is incident on the reflected light receiving element 206 via the mirror 222, instead of hitting the target 214 to be measured of the projected light beam 211 projected from the laser light source 200A, and the projected light The time measuring circuit 2 measures the delay time with respect to the reference signal 213 obtained when a part of the beam 211 is incident on the reference light receiving element 200B.
00D, the distance between the shape measuring system 200 and the target 214 is calculated based on this delay time.
The target shape is measured by calculating with E.

Next, referring to the flow chart shown in FIG. 7, a shape measuring method using the shape measuring system 200 will be described for each step. In the conventional shape measuring method, a laser projecting step is mainly used. And a reference light receiving step, a reflected light receiving step, a time measuring step, and a calculating step. When the shape measurement is started, first, in the laser projecting step (step S200), the laser light source 200A is operated. The projected beam 211 is projected toward the target 214.
The projection beam 211 is projected as a pulse train composed of pulses at predetermined time intervals.

A part of the projection beam 211 emitted from the laser light source 200A is part of the reference light receiving step (step S20).
In 1), for example, a beam splitter (not shown)
Is guided to the reference light receiving element 200B via the light source, and converted from an optical signal to an electric signal to become a reference signal 213.

On the other hand, a reflected light receiving step (step S20)
In 2), the projection beam 211 emitted from the laser light source 200A is reflected by the target 214 and then enters the mirror 222 as the received beam 205. After that, the received light beam 205 is reflected by the mirror 222 and guided to the reflected light receiving element 206, where it is converted into an electric signal and becomes a reflected signal 200g.

Next, the time measuring step of step S203 will be described with reference to FIG. 6 which is a chart showing the operation timing of the shape measuring system 200 shown in FIG. 5, in addition to FIGS. The time measuring process includes a rough measuring process and a precise measuring process. First, in the rough measurement process, the rough measurement circuit 240d generates the light emission timing signal 200h generated by discriminating the specific position of the waveform from the reference signal 213, and in the fine measurement process, the reflection signal is generated by the fine measurement circuit 240c. A light reception timing signal 200i generated by discriminating a specific position of the waveform from 200g is generated.

On the other hand, from the clock 230, a pulse signal train consisting of a pulsed clock signal 230a is a rough measuring circuit 2.
40d and the precision measurement circuit 240c each have a clock cycle 23.
3, the delay time T is measured from the difference between the light emission timing signal 200h and the light reception timing signal 200i, and in the calculation step (step S204), the shape measuring system 200 and the target are measured based on the following equation (1). The distance R to 214 is calculated. R = V × T / 2 Equation (1) Here, V represents the speed of light.

More specifically, a few c are used for distance measurement.
When a measurement accuracy of m or less is required, a time accuracy of about 100 ps is required. However, the method of digitally counting the clock signal 230a cannot meet the accuracy requirement due to the limitation of the circuit operation speed. Have difficulty.
Therefore, in the conventional method, in order to obtain the above-mentioned delay time T, the rough time from the light emission timing signal 200h to the light reception timing signal 200i is counted by counting the digital clock period 233 capable of measuring a wide range of time. The time is measured as the rough measurement time 200K, and the time difference from the generation of the light emission timing signal 200h to the end of the clock signal 230a thereafter (the first precise measurement time 201
j) and the time difference from the generation of the light reception timing signal 200h to the end of the clock signal 230a thereafter (the second precise measurement time 202j) are measured by a narrow range but accurate analog time-voltage conversion. Then, the method of calculating the distance R by the following equation (2) is adopted.

R = V × (Ts1 + Tr−Ts2) / 2 (2) Here, Tr is the coarse measurement time 200K, Ts1 is the first precise measurement time 201j, and Ts2 is the second precise measurement time 202j. It represents. That is, the first and second precise measurement times 201j,
The precise measurement time signal 200j representing 202j and the rough measurement time signal 200k representing the rough measurement time 200K are input to the arithmetic circuit 200E, where the above-mentioned calculation is performed.
The obtained distance information is output as a distance signal. Thereby, the shape of the target 214 can be measured.

The above distance measuring process is performed by the arithmetic circuit 200E.
The mirror angle signal 220 from the reflected light receiving means 200C
To the mirror control circuit 221 of the
It is possible to measure height information for the target two-dimensional plane by individually performing each pixel from the first pixel 207c1 to the Nth pixel 207cN while scanning two-dimensionally around each axis.

[0012]

In the above-mentioned conventional shape measuring system, since the mirror 222 is mechanically scanned, a waiting time is required from the measurement of one pixel to the measurement of the next pixel. Therefore, in the case where the target 214 is a flying object such as a missile that moves at high speed, the position of the target 214 changes while scanning the mirror 222 for all the pixels, and therefore there is an error in the two-dimensional position and height measurement values. There was a problem that the target shape could not be measured accurately. Moreover, it is necessary to precisely control the mirror to perform measurement.

Therefore, a main object of the present invention is to provide a shape measuring method and system capable of accurately measuring the shape of a target that moves at a high speed.

Another object of the present invention is to provide a shape measuring method and system in which a rough measuring circuit is made common and the calculation speed can be improved.

[0015]

As a result of intensive studies, the present inventors have received reflected light with a plurality of reflected light receiving elements, and have a pair of reflected signals output from each reflected light receiving element. By measuring the delay time with a measuring circuit including a rough measuring circuit and a precise measuring circuit, it is possible to solve the above-mentioned problem with respect to a target moving at high speed, and the first invention is based on the knowledge. It was completed.

However, although the above-mentioned problem is solved by the first invention, the first invention performs the rough measurement and the precise measurement on the reflection signal output from each reflected light receiving element. Therefore, the measuring circuit becomes rather complicated and the entire system becomes large.
It was found that there is room for improvement in the invention of.

Therefore, as a result of further diligent research, the present inventors have found that when measuring a target shape, the absolute distance accuracy to the target is not so important, and the relative distance accuracy involved in the target shape measurement is not so important. It was found to be important.
Then, the present inventors have completed the second invention capable of solving the problem of the first invention by arranging the rough measurement distance in at least one rough measurement circuit based on this knowledge. .

Therefore, in order to achieve the above-mentioned object, the present invention according to claim 1 provides a reflection signal obtained from the reflected light of the laser light projected from the laser light source, which is repelled at the target. The shape of the target is measured by detecting a delay time between the laser light and a reference signal obtained from a part of the reference light based on a clock signal sequence, and calculating the target distance from the delay time. In the shape measuring method, the reflected light is received using a plurality of reflected light receiving elements, and a reflected signal is output from each reflected light receiving element,
The feature is that distance measurement is performed in parallel for each reflection signal.

According to the present invention as defined in claim 2,
It is preferable that the received light beam of each reflected light receiving element forms a predetermined angle with respect to the incident direction of the reflected light.

According to the present invention as defined in claim 3,
The delay time is a first precise measurement time which is a time difference between the light emission timing signal generated based on the reference signal and the corresponding clock signal in the clock signal sequence, and the light reception timing signal and the clock signal generated based on the reflection signal. The second precise measurement time, which is the time difference between the corresponding clock signals in the sequence, and the rough measurement time obtained from the number of clock cycles between the corresponding clock signals of both, and the rough measurement is performed for each of the reflected signals. It is designed to measure time.

According to the present invention of claim 4,
The delay time is the time difference between the light reception timing signal generated based on the reflection signal and the corresponding clock signal in the clock signal sequence corresponding to the measurement end timing signal generated by delaying the light reception timing signal. It is the time difference between the time measurement and the corresponding clock signal of the clock signal sequence corresponding to the light emission timing signal generated based on the reference signal and the corresponding clock signal of the clock signal sequence corresponding to the measurement end timing signal. It is calculated from the rough measurement time, and the rough measurement distance is measured for one reflection signal.

In order to achieve the above object, the present invention according to claim 5 provides a laser light source for projecting a laser light, and a reference for receiving a part of the laser light as a reference laser light and converting it into a reference signal. Light receiving means, a reflected light receiving means having a plurality of reflected light receiving elements for receiving the reflected light of the laser light that has rebounded against the target and converting it into a reflected signal, and the reflected signal and the reference signal A shape measuring system comprising: a time measuring unit that detects a delay time between the signals in parallel for each reflection signal; and a calculating unit that calculates a distance to the target based on the detected delay time. is doing.

According to a sixth aspect of the present invention, in the shape measuring system according to the fifth aspect, the received light beams of the respective reflected light receiving elements form respective predetermined angles with respect to the incident direction of the reflected light. There is.

Further, in the shape measuring system according to the present invention as set forth in claim 7, the time measuring means for detecting the delay time between the reflected signal and the reference signal in parallel for each reflected signal is at least one coarse unit. The coarse measuring circuit includes a measuring circuit and a plurality of precise measuring circuits, wherein the rough measuring circuit measures a rough measuring distance to the target with respect to at least one reflection signal of the reflection signals. For the reflected signal, the time difference between the reflected signal and the clock signal corresponding to the reference signal is detected.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. Further, as will be understood from the following description, the present invention is not limited to this embodiment, and various modifications can be made.

FIG. 1 is a diagram schematically showing the configuration of a shape measuring system 10 according to a first embodiment of the present invention. The shape measuring system 10 is first described briefly as a laser light source 10A, A reference light receiving element 10B for receiving the reference light, a reflected light receiving means 10C having a plurality of reflected light receiving elements 16 including corresponding pixels c1 to cN, and a precise measurement described later for performing distance measurement for each pixel. It includes a time measuring means 10D having a circuit and a rough measuring circuit, and a calculating means 10E for calculating a distance to the target 14 based on each signal from the time measuring means 10D. Further, the time measuring means 10D includes a clock 30 which generates a clock signal as a time reference in a pulse form.

The laser light source 10A is not particularly limited as long as it can project the light on the target 14, and an appropriate laser light source can be used. Since the present invention measures time, the wavelength of the laser light projected from the laser light source 10A is appropriately selected and used depending on, for example, the resolution in the distance direction, the laser reflectance of the capture target, or the like. To be done.

In FIG. 1, the reference light receiving means 10B is
A part of the projection beam 11 emitted from the laser light source 10A is received through, for example, a beam splitter (not shown), and the projection beam 11 is used as a reference signal (electrical signal).
Convert to 13. The light emission timing when the projection beam 11 is projected is recognized based on the reference signal 13 obtained by the reference light receiving unit 10B. The reference light receiving unit 10B is not particularly limited as long as it has this function, and a conventionally known light receiving element can be used.

In the first embodiment, the reflected light receiving means 10C comprises a plurality of reflected light receiving elements 1 arranged in a grid pattern.
It consists of 6. The received light beam 15 corresponding to each reflected light receiving element 16 spreads in the shape of a quadrangular pyramid in the incident direction of the reflected light (see FIG. 1) and is defined as a pixel. Therefore, it can be considered that each of the received light beams 15 indicates a range in which only light incident from the axial direction of the quadrangular pyramid can be detected as a signal. In this way, the reflected light enters each reflected light receiving element 16 and is converted into reflected signals g1 to gN there. These series of steps are performed at substantially the same time, that is, in parallel, at each reflected light receiving element 16.

Further, in this preferred embodiment, it can be seen that each received light beam 15 or each pixel c1 to cN is inclined at a predetermined angle with respect to the incident direction of the reflected light. Therefore, by knowing the incident angle of the reflected light with respect to the received light beam of each reflected light receiving element 16, it is not necessary to mechanically control the movement of the mirror as in the conventional case, in other words, without using the mirror. By measuring the distance between the site on the target 14 and the shape measuring system in the incident direction, the unevenness of the target surface can be known and the target surface shape can be recognized.

The lattice arrangement of the reflected light receiving element 16 is composed of L rows and M columns, and the number of L is 10 to 30, though it varies depending on the divergence angle of the received light beam and the size of the target to be measured.
The number of M is 10-30. The value obtained by multiplying L and M is preferably 100 to 1000. When the value obtained by multiplying L and M is 1000 or more, although the obtained accuracy is almost the same, the circuit becomes complicated and it is disadvantageous from the economical point of view, which is not preferable. On the other hand, when the value obtained by multiplying L and M is 100 or less, the accuracy is deteriorated, which is not preferable. Further, it is obvious that the grid shape is not limited to the square shape and may be another shape. The reflected light receiving means 10C is not particularly limited as long as it has a function of converting the reflected light into reflected signals g1 to gN as electric signals, and a conventionally known light receiving element is used as the reflected light receiving means. You can Specifically, a CCD, a photodiode, and a photomultiplier tube can be used as the reflected light receiving means.

The time measuring means 10D includes a plurality of time measuring circuits 10d1 to 10dN and a clock 3 as a time reference.
0, and each time measuring circuit is composed of a precise measuring circuit d and a rough measuring circuit f. Then, these time measuring circuits are provided for the above-mentioned pixels and thus the reflected light receiving element 1
6 is provided so as to correspond to 6 and the delay time of each reflected light receiving element is measured in parallel in each time measuring circuit. With such a configuration, the measurement time is shortened as compared with the conventional shape measurement method that is individually performed, and thus the target shape can be accurately measured even when the target moves at high speed.

The computing means 10E and the shape measuring system 10 and the target based on the precise measurement time signal and the coarse measurement time signal obtained by the precise measurement circuit d and the coarse measurement circuit f of each time measurement circuit as described later. The distance between 14 and thus the target shape is determined.

Next, with reference to FIGS. 1 and 2, a method of shape measurement using the shape measurement system 10 according to the first embodiment described above will be described for each step. The shape measuring method includes a laser projecting step, a reference light receiving step, a reflected light receiving step, a time measuring step, and a calculating step, similar to the conventional example described with reference to FIGS. Contains.

First, in the laser projecting step, when the projecting beam 11 is projected from the laser light source 10A, the projecting beam 11 advances toward the target 14, and a part of the projecting beam 11 goes toward the reference light receiving means 10B. And proceed. In this case, Goal 1
It is preferable that the projection beam 11 is projected so that the entire area 4 is illuminated. Then, in the reference light receiving step, a part of the light projection beam 11 projected from the laser light source 10A is incident on the reference light receiving means 10B and converted into a reference signal 13 representing a light emission timing, and then a light emission timing signal. h1-
In order to generate hN respectively, it is input to each rough measuring circuit f1 to fN of the time measuring means 10D.

Further, in the reflected light receiving step, the projected light beam 11 is reflected by the target 14, and the reflected light is incident on the reflected light receiving element 16 corresponding to the pixels c1 to cN of the reflected light receiving means 10C, and each of them receives an electric signal. After being converted into, the corresponding reflection signals g1 to gN are input to the precise measuring circuits d1 to dN of the time measuring means 10D.

Next, the time measuring step will be described with reference to FIG. FIG. 2 is a diagram showing operation timings for pixels in the first embodiment. Similar to the conventional example,
The first precise measurement time 1j represents the time difference of the change point (falling portion) of the clock signal 30-1 immediately after the generation timing of the light emission timing signal h, and the second precise measurement time 2j is the light reception timing signal i. It represents the time difference of the change point of the first clock signal 30-2 with respect to the generation time, and the rough measurement time K is
The clock signal 30- immediately after the light reception timing signal i is generated from the change point of the first clock signal 30-1 described above.
It is defined to represent the time corresponding to the number of clock cycles 33 up to the change point of 2.

Each of the rough measuring circuits f1 to fN discriminates a specific position of the waveform by the input reference signal 13 and outputs the light emission timing signals h1 to hN to each of the precise measuring circuits d1 to dN, and from the clock 30. Based on the input clock signal, the counting of the clock cycle 33 is started to start measuring the rough measurement time K.

On the other hand, the precise measuring circuits d1 to dN respectively receive the corresponding light emission timing signals h1 to hN and measure the first precise measuring time 1j which is the difference from the changing point of the clock signal 30-1. After that, each of the precise measurement circuits d1 to dN receives the corresponding reflection signals g1 to gN, determines a specific position of the waveform, and outputs the light reception timing signals i1 to iN to the rough measurement circuits f1 to fN.
It outputs to N and measures the above-mentioned second precise measurement time 2j. Each of the rough measuring circuits f1 to fN has a light receiving timing signal i1 to
When iN is received, the measurement of the rough measurement time K is completed. The precise measurement time signals j1 to jN corresponding to the measured first precise measurement time 1j and the second precise measurement time 2j and the coarse measurement time signals k1 to kN corresponding to the coarse measurement time K are input to the calculating means 10E. .

Finally, in the calculation step, the calculation means 10
Based on various signals input to E, the distance Ri between the shape measuring system 10 and the target 14 is calculated according to the following equation (3).
To calculate. Ri = V × (Ts1j + Trk−Ts2j) / 2 (3) where V is the speed of light, Tslj is the first precise measurement time 1j, T
rk represents the rough measurement time K, and Ts2j represents the second precise measurement time 2j. Then, the distance measurement for each of the pixels c1 to cN is performed in parallel with respect to the light emission of the projection beam 11, and the distance to the target and the target shape are measured by performing the above steps. Of.

As described above, according to the first embodiment, the reception of the reflected light and the conversion into the reflected signal are performed by each reflected light receiving element, and the delay time with respect to each reflected light receiving element is measured. Are performed in parallel with the emission of the projection beam 11. Therefore, the measurement time of the delay time for each reflected light receiving element is shortened, so that the shape of the stationary target can be measured, and the moving target,
In particular, it is possible to measure a target shape such as an airplane, a missile, a rocket or the like that moves at high speed with high accuracy. In addition, since the mirror is not used, there is no need to mechanically control the mirror as in the past, which not only improves operability, but also eliminates the control circuit used to control the mirror. The entire system can be miniaturized through simplification.

Next, a second embodiment of the present invention will be described. Like elements having substantially the same functions as those described in the first embodiment with reference to FIGS. 1 and 2 are designated by like reference numerals. The explanation is omitted or simplified.
Since the shape measuring system according to the first embodiment is configured to have both the precise measuring circuit and the rough measuring circuit for one pixel, the larger the number of pixels, the larger the circuit becomes.
In the embodiment, the coarse measurement circuit is simplified, and the coarse measurement circuit is shared by a plurality of precise measurement circuits to reduce the size of the circuit.

FIG. 3 is a schematic diagram showing the configuration of the shape measuring system 100 according to the second embodiment of the present invention. As shown in FIG. 3, the shape measuring system 100 includes a laser light source 100A, a reference light receiving unit 100B including a plurality of reflected light receiving elements for receiving reference light, and a reflection light receiving unit for receiving reflected light. Light receiving means 100C and time measuring means 1 for measuring the delay time T for each reflected light receiving element
00D and a calculating means 100E for calculating a distance based on a signal from the time measuring means 100D, a main part is constituted.

The time measuring means 100D includes a plurality of precise measuring circuits 100d1 to 100dN, a single rough measuring circuit 53, a light receiving determination circuit 57, a delay circuit 51, and a clock for generating a clock signal serving as a time reference. It is composed of 30 and. In addition, the precise measurement circuits 100d1 to 100dN include the plurality of reflected light receiving elements 1 that constitute the reflected light receiving unit 100A.
Further, it is provided so as to correspond to the pixels 100c1 to 100cN, and the precise measuring circuits 100d1 to 100d1.
The earliest reflected signal among the reflected signals input to 00dN is configured to be input to the rough measurement circuit 53 via the light reception determination circuit 57 and the delay circuit 51.

Next, a method for measuring a target shape using the shape measuring system in the second embodiment will be described. Similar to the first embodiment, this method includes a laser projecting step, a reference light receiving step, a reflected light receiving step, a time measuring step, and a calculating step. Here, each step except the time measuring step is the same as that described in the first embodiment, so only the time measuring step will be described.

FIG. 4 is a diagram showing the operation timing for the pixels in the second embodiment. In this case, precise measurement time 1
02j represents the time difference from the generation of the light reception timing signal 54i to the change point of the clock signal 30-3 immediately after the generation of the measurement end timing signal 121, and the rough measurement time 1
00K is the time corresponding to the number of clock cycles 33 from the change point of the first clock signal 30-1 after the light emission timing signal 100h to the change point of the clock signal 30-3 immediately after the measurement end timing signal 121 is generated. Is defined as representing.

In the time measuring step, each precision measuring circuit 100
With respect to the reflection signals g1 to gN, the d1 to 100 dN discriminate the respective specific positions of the waveforms and output the light reception timing signals 54i1 to 54iN to the light reception determination circuit 57. The light receiving determination circuit 57 receives the light receiving timing signal 54i1.
~ Based on the light reception timing signal 54iN, the light reception timing determination signal 52 serving as the reference of the precise measurement time is output. Since this is delayed by the delay circuit 51, it is shown on the left side of the light reception timing signal 54i in FIG. ing.

Here, as the determination algorithm of the light reception timing determination signal 52, a method of outputting when the first light reception timing signal is input, or an output when a plurality of light reception timing signals for noise removal are input Can be used. After that, the light reception timing determination signal 52
Is delayed by the delay circuit 51 by a time represented by a delay time 131 that covers a size assumed as a target, and is output as a measurement end timing signal 121.

Subsequently, the pixels 100c1 to 100cN
The time measurement method will be explained for the system corresponding to. The rough measuring circuit 53 starts measuring the rough measuring time 100K based on the light emission timing signal 100h generated by discriminating the specific position of the waveform from the reference signal 103, and outputs the measurement end timing signal output from the delay circuit 51. After receiving 121, the measurement of the rough measurement time 100K is completed. On the other hand, the precision measuring circuit 10
0d1 to 100dN is the clock signal 30- immediately after the light reception timing signal 54i and the measurement end timing signal 121.
The precise measurement time 102j, which is the difference from the change point of 3, is measured.

The precise measurement time signal 100j corresponding to the measured precise measurement time 102j and the coarse measurement time signal 100k corresponding to the rough measurement time interval 100K are input to the calculating means 100E and, after distance calculation, output as a distance signal. It Here, when the precise measurement time 102j is Tsj and the rough measurement time 100K is Tr, the distance Ri can be calculated by the equation (4). Ri = V × (Tr-Tsj) / 2 (4) Here, V represents the speed of light. In the second embodiment, needless to say, the distance measurement for each of the pixels 100c1 to 100cN is performed in parallel with respect to the emission of the projection beam 11.

In the shape measuring method and system according to the second embodiment, as can be seen by comparing equations (3) and (4), Tsl corresponding to the first precise measurement time 1j in equation (3).
Although the absolute distance accuracy deteriorates by j, the relative distance accuracy between pixels is the same as in the first embodiment, and the time measuring circuit is greatly simplified and the circuit scale is reduced. Therefore, in addition to the action and effect of the first embodiment, the action and effect that the reliability of the system can be improved and downsized can be obtained.

Although the present invention has been described above by exemplifying the first and second embodiments, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. For example, for various timings based on the light emission timing signal and the light reception timing signal, the rising change point may be used instead of the pulse falling change point as in the embodiment. Further, in the second embodiment, only one rough measuring circuit is provided,
A plurality of reflected light receiving elements may be divided into a plurality of groups, and one rough measuring circuit may be provided in each group. Further, the reflected light receiving means may be provided with an optical amplifier circuit.

Furthermore, according to another embodiment of the present invention, a recording medium containing a program for executing each step of the shape measuring method using a laser, and a reflected light receiving light used for the shape measuring system. It goes without saying that means are provided.

[0054]

As can be understood from the above description, according to the present invention as set forth in claims 1 and 5, reflected light is received using a plurality of reflected light receiving elements, and each reflected light is received. The device outputs the reflection signal and measures the distance for each reflection signal in parallel. Therefore, it is possible to measure the stationary target without moving complicated mechanical control and move at high speed. The shape of the target can be measured with high accuracy.

According to the second and sixth aspects of the present invention, the received light beam of each reflected light receiving element forms a predetermined angle with respect to the incident direction of the reflected light. Since the incident angle of the reflected light is known, it becomes easy to recognize the target surface shape such as unevenness.

According to the present invention as defined in claim 3,
The delay time is a first precise measurement time which is a time difference between the light emission timing signal generated based on the reference signal and the corresponding clock signal in the clock signal sequence, and the light reception timing signal and the clock signal generated based on the reflection signal. The second precise measurement time, which is the time difference between the corresponding clock signals in the sequence, and the rough measurement time obtained from the number of clock cycles between the corresponding clock signals of both, and the rough measurement is performed for each of the reflected signals. Since it is configured to measure time, the accuracy of the measured distance is high, so that it can be particularly adapted to an application in which such characteristics are required.

According to the present invention as defined in claim 4,
The delay time is the time difference between the light reception timing signal generated based on the reflection signal and the corresponding clock signal in the clock signal sequence corresponding to the measurement end timing signal generated by delaying the light reception timing signal. It is the time difference between the time measurement and the corresponding clock signal of the clock signal sequence corresponding to the light emission timing signal generated based on the reference signal and the corresponding clock signal of the clock signal sequence corresponding to the measurement end timing signal. Since the rough distance is calculated from the rough measurement time and the rough distance is measured for one reflection signal, the accuracy of the target distance is slightly lowered, but the shape can be measured with high accuracy. It is especially suitable for applications where the coarse measurement circuit is one system and the system can be simplified, and the accuracy of the distance to the target is rough. .

Further, according to the shape measuring system of the present invention as set forth in claim 7, the time measuring means for detecting the delay time between the reflection signal and the reference signal in parallel for each reflection signal is at least one. It includes a rough measuring circuit and a plurality of precise measuring circuits, wherein the rough measuring circuit measures a rough measuring distance to the target for at least one reflection signal of the reflection signals, and the precise measuring circuit comprises: Since the delay time between the reflection signal and the reference signal is detected for each reflection signal, the target distance accuracy is slightly reduced, but the shape is the same as in the present invention according to claim 4. In addition to being able to measure with high accuracy, the coarse measurement circuit can be simplified into one system, and it is particularly suitable for applications where the accuracy of the distance to the target is rough.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a shape measuring system according to a first embodiment of the present invention.

FIG. 2 is a chart showing operation timings for pixels in the first embodiment shown in FIG.

FIG. 3 is a schematic diagram showing the configuration of a shape measuring system according to a second embodiment of the present invention.

FIG. 4 is a chart showing operation timings for pixels in the second embodiment shown in FIG.

FIG. 5 is a diagram showing a configuration of a conventional shape measuring system.

6 is a chart showing operation timings for pixels in the shape measuring system shown in FIG.

FIG. 7 is a flowchart of a conventional shape measuring method.

[Explanation of symbols]

10A laser light source 10B Reference light receiving means 10C reflected light receiving means 10D time measuring means 10E computing means 11 Projection beam (laser light) 13 Reference signal 14 goals 15 Received beam 16 Reflected light receiving element 30-1 Clock signal 30-2 Clock signal 30-3 Clock signal 53 Rough measurement circuit 54i1 Light reception timing signal 54i2 Light reception timing signal 54iN Light receiving timing signal 100A laser light source 100B Reference light receiving means 100C reflected light receiving means 100D time measuring means 100E computing means 100d1 precise measurement circuit 100d2 precise measurement circuit 100dN precise measurement circuit 103 reference signal 121 Measurement end timing signal 1j 1st precise measurement time 2j Second precise measurement time d1-dN precision measuring circuit f1 to fN rough measurement circuit g1-gN reflection signal h1 to hN light emission timing signal i1 to iN light reception timing signal K rough measurement time T delay time

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA06 AA51 BB15 DD02 DD06                       FF12 FF32 FF43 GG04 GG08                       JJ03 JJ17 JJ18 JJ26 LL46                       NN02                 5J084 AA05 AD01 BA03 BA51 CA03                       EA04

Claims (7)

[Claims] 1. A reflection signal between a reflection signal obtained from a reflection light of a laser light projected from a laser light source which is repelled by hitting a target and a reference signal obtained from a reference light of a part of the laser light. The delay time is detected based on the clock signal train,
In a shape measuring method for measuring the target shape by calculating the target distance from the delay time, the reflected light is received using a plurality of reflected light receiving elements, and a reflected signal is received from each reflected light receiving element. Along with outputting, the distance measurement is performed in parallel for each reflection signal,
Shape measurement method using a laser. 2. The received beam of each of the reflected light receiving elements comprises:
The shape measuring method according to claim 1, wherein the shape measuring method forms a predetermined angle with respect to the incident direction of the reflected light. 3. The first delay time, which is a time difference between a light emission timing signal generated based on the reference signal and a corresponding clock signal of the clock signal sequence, and the delay time based on the reflection signal. It is calculated from the generated light reception timing signal and the second precise measurement time which is the time difference between the corresponding clock signals in the clock signal sequence, and the rough measurement time obtained from the number of clock cycles between the corresponding clock signals. The shape measuring method according to claim 1 or 2, wherein the rough measurement time is measured for each of the reflection signals. 4. The delay time is a corresponding clock signal in the clock signal sequence corresponding to a light reception timing signal generated based on the reflection signal and a measurement end timing signal generated by delaying the light reception timing signal. A precise measurement time which is a time difference between the clock signal sequence and a corresponding clock signal of the clock signal sequence corresponding to the light emission timing signal generated based on the reference signal, and the clock signal sequence corresponding to the measurement end timing signal. The shape measuring method according to claim 1 or 2, wherein the rough measuring distance is calculated from a rough measuring time which is a time difference from the corresponding clock signal, and the rough measuring distance is measured for one reflection signal. 5. A laser light source for projecting laser light, reference light receiving means for receiving a part of the laser light as reference laser light and converting it into a reference signal, and hitting a target of the laser light. Reflected light receiving means having a plurality of reflected light receiving elements for receiving the returned reflected light and converting it to a reflected signal, and time measurement for detecting the delay time between the reflected signal and the reference signal in parallel for each reflected signal. A shape measuring system using a laser, comprising: means and a calculating means for calculating a distance to the target based on the detected delay time. 6. The received beam of each of the reflected light receiving elements comprises:
The shape measuring system according to claim 5, wherein the shape measuring system forms respective predetermined angles with respect to the incident direction of the reflected light. 7. The time measuring means for detecting a delay time between the reflected signal and the reference signal in parallel for each reflected signal includes at least one rough measuring circuit and a plurality of fine measuring circuits, and the rough measuring circuit includes: The measuring circuit is for measuring a coarse distance to the target for at least one reflected signal of the reflected signals, and the precise measuring circuit is for delaying between the reflected signal and the reference signal for each reflected signal. The shape measuring system according to claim 5, which detects time.