JPH0450703A - Monitor device of speckle length measuring instrument - Google Patents

Abstract

PURPOSE:To easily adjust a fitting position by displaying one of the quantity and inclination of light received a linear image sensor and the surface state of an object body according to the level of a monitor signal. CONSTITUTION:The signal outputted by a gain control amplifier 32 is fed back to the control signal terminal of an amplifier 3 thorough an integrator 36 and also inputted to an arithmetic circuit 51. Further, the image signal obtained from a sample and hold circuit 31 is generated in each period of the start signal supplied from a timing control circuit 41 to the liner image sensor and the generation term of the image signal in the period corresponds to the one-scan time of a speckle pattern by the linear image sensor. Then the image signal from the circuit 31 is inputted to the mean level arithmetic circuit 52 of the circuit 51. Then the frequency divider 42 of the circuit 41 divides the generation term of the image signal into plural areas and inputs the divided timing signal to the circuit 52. A display control circuit 53 outputs a monitor signal M to an indicator 62.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a speckle length measuring meter that measures the amount of movement of an object by using a speckle pattern generated by diffused light from the surface of an object irradiated with a laser beam. It is related to.

[Conventional technology]

Conventionally, a target object is irradiated with a laser beam emitted from a semiconductor laser, and the speckle pattern generated by the diffused light from the object's surface is observed, and based on changes in the speckle pattern due to movement or deformation of the object, etc. The amount of movement of the object,
A method of measuring the amount of deformation, etc. is known.

In addition, in the technical field of video processing, CCDs that exhibit high resolution have been put into practical use as image sensors that replace conventional image pickup tubes, and by applying this CCD as a speckle pattern detection sensor, it is possible to detect speckle patterns. It is possible to accurately convert it into an image signal,
As a result, highly accurate measurement results can be obtained.

[Problem to be solved by the invention]

Incidentally, since the speckle pattern is formed based on diffusely reflected light from the surface of the target object, Svenkl length measurement is theoretically impossible if the surface of the object is extremely smooth like a mirror surface.

In such a case, it is necessary to take measures such as forming a rough surface on the target object.

Furthermore, even if length measurement is possible in principle, if the object surface is relatively smooth such as a metal surface, the distribution of the image signal of the speckle pattern obtained from one beam spot on the object surface will be It has a mountain-shaped distribution with a high end and a low end.

Therefore, positioning errors occur when installing the length measuring meter,
When a laser beam obliquely enters the surface of an object during measurement, the peak of the light intensity distribution shifts from the center to the edge, and the signal level at the bottom of the distribution drops accordingly.

As a result, when the image signal is subjected to various processes for length measurement, the level of the skirt portion may not reach the threshold level, and there is a possibility that a signal processing error may occur.

In such a case, it is necessary to adjust the optical axis of the laser beam so that it is perpendicular to the surface of the target object.

Furthermore, depending on the distance to the object to be measured and the color of the object, the amount of light received by the image sensor may be too large or too small, making accurate measurement impossible.

With conventional speckle length measuring meters, prior to actual length measurement,
It is not possible to obtain information such as the surface condition of the object to be measured, the magnitude of the amount of light received, or information on accurately adjusting the direction of the optical axis of the laser beam, which detracts from the advantages of the speckle length measuring meter.

An object of the present invention is to provide a speckle length measuring meter monitoring device that can accurately obtain this information.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a laser beam generator that irradiates a laser beam onto the surface of a moving object to be measured, and a laser beam generator that irradiates the surface of the target object with a laser beam. A speckle measurement system includes a one-dimensional image sensor that photoelectrically converts a speckle pattern appearing on an observation surface into an image signal, and a measurement circuit that calculates the amount of movement of an object based on changes in the image signal as the object moves. A timing signal for dividing the distribution of image signals obtained from the one-dimensional image sensor into a plurality of divided regions in the scanning direction of the one-dimensional image sensor corresponding to the laser beam irradiation spot in the long timer. a timing control circuit for generating the image signal; an arithmetic circuit to which the image signal and the timing signal are supplied; and an arithmetic circuit that calculates the average level in each divided area of the image signal to create a monitor signal; and a display according to the level of the monitor signal from the arithmetic circuit. and a display means for displaying at least one of the amount of light received by the one-dimensional image sensor, the tilt, and the surface condition of the target object according to the level of the monitor signal. This constitutes a long-range monitor device.

Here, a changeover switch may be provided so that at least two displays among the amount of light received by the one-dimensional image sensor, the tilt, and the surface state of the target object can be switched. Multiple LEDs can also be used.

[Operation] When the optical axis of the laser beam is set perpendicular to the surface of the target object, the distribution of the image signal becomes symmetrical, and as a result of dividing the image signal by the timing signal, the first half and the second half are divided. The average level becomes the same, and the display means indicates that the slope is appropriate.

For example, when a display means in which a plurality of LEDs are arranged in a straight line is used, the LED located in the center is lit.

When the optical axis is tilted, the distribution of image signals is biased to either the left or right side, causing a difference in the average level in each divided area, and a corresponding display is performed accordingly.

Therefore, if the optical axis is adjusted so that the display on the display means is appropriate, the optical axis will be set perpendicular to the surface of the target object.

Furthermore, when the surface of the target object is rough, the distribution of the image signal becomes an average distribution without bias, and as a result of dividing the image signal by the timing signal, the average level of each divided area becomes -. .

If the object surface is smooth, the image signal distribution will be mountain-shaped, resulting in a difference in the average level of each divided region.

From this, it is determined whether the reflection state of the surface of the object to be measured is specular reflection or diffuse reflection, and the result is displayed on the display means.

For example, when a plurality of LEDs are used, display can be achieved by lighting up all the LEDs during diffuse reflection, and lighting up the LEDs corresponding to positions where the signal level is particularly high during specular reflection.

Further, a display is performed on the display means according to the amount of laser light received by the one-dimensional image sensor.

For example, the amount of light is displayed based on the number of LEDs lit.

[Example〕 The details of the present invention will be explained based on illustrated embodiments.

FIG. 1 is a diagram illustrating complaints regarding a monitor device for a speckle length measuring meter according to the present invention.

That is, the present invention includes a laser beam generator 1 that irradiates a laser beam onto the surface of a moving object to be measured, and a photoelectric generator that converts a speckle pattern appearing on an observation surface opposite the laser beam irradiation surface of the target object into an image signal. Compatible with laser beam irradiation pants in a sube-nockle length measuring meter that includes a one-dimensional image sensor 2 for converting the image signal and a measurement circuit 3 that calculates the amount of movement of the object based on changes in the image signal as the object moves. a timing control circuit 4 that generates a timing signal for dividing the distribution of image signals obtained from the one-dimensional image sensor 2 into a plurality of divided regions in the scanning direction of the one-dimensional image sensor 2; an arithmetic circuit 5 to which signals and timing signals are supplied, and which calculates the average level in each divided area of the image signal to create a monitor signal; and a display means 6 which displays according to the level of the monitor signal from the arithmetic circuit 5. and the one-dimensional image sensor 2 according to the level of the monitor signal.
This is a monitor device for a speckle length measuring meter, characterized in that it displays the amount of light received by the device, its inclination, and the surface condition of a target object.

Next, the overall configuration of the speckle length measuring meter will be explained.

As shown in Figure 2, go to the measurement using the speckle length measuring meter.
In the casing 71, a semiconductor laser beam 1-11 having a beam exit 12, an electronic cooling device 13 for controlling the temperature of the semiconductor laser at a constant level, an image sensor 21 in which CCDs are arranged in a one-dimensional direction, etc. are installed. It is configured as follows, and is installed facing the object to be measured 8.

As shown in the figure, the casing 71 has a rectangular parallelepiped main body with an opening on one side, and a rubber gasket 72 and a cover 73 are fixed to the opening with screws to form a closed container.

A window 74 for laser beam emission is provided in the front wall of the casing 71.

The one-dimensional image sensor 21 includes the semiconductor laser unit 1
The optical axis of the laser beam emitted from the dimensional image sensor 21 is perpendicular to the array direction of the CODs constituting the dimensional image sensor 21, that is, the scanning direction, and the central position of the scanning area of the CCD is the optical axis of the laser beam. and is positioned on a plane that is perpendicular to the scanning direction.

FIG. 3 shows an example of the configuration of a measuring circuit connected to the measuring head 7 to calculate and display the amount of movement of an object based on an image signal from the one-dimensional image sensor 21.

As is well known, the one-dimensional image sensor 2I repeats scanning in the CCD array direction at a constant cycle based on a reset signal, a start signal, and a shift signal sent from the Hashfer amplifier 22.

The output signal of the one-dimensional image sensor 21 is transmitted to the first stage amplifier 2.
3 to the sample and hold circuit 31, thereby removing noise peculiar to CCD.

The output signal of the sample hold circuit 31 is sent to the binarization circuit 33 via the gain control amplifier 32, whereby the image signal S shown in FIG. 4 is binarized, and the binarized signal is further correlated. The cross-correlation function between the speckle pattern at the reference position of the target object and the speckle pattern after movement is sequentially calculated while shifting the reference position, and the calculation results are sent to the microcomputer 35. .

The microcomputer 35 calculates the moving distance of the object from the peak position of the cross-correlation function, and displays the result on the display 6.
Display digitally on 1.

Further, the above-mentioned HFA amplifier 22 and sample hold circuit 3
1. The operations of the binarization circuit 33 and the correlator 34 are controlled by timing signals supplied from the timing control circuit 41, respectively.

Next, the configuration and operation of the monitor device according to the present invention will be described in detail.

FIG. 5 is a simplified block diagram of the monitor device of the present invention.

The signal output from the gain control amplifier 32 is transmitted to the integrator 3
6, the signal is fed back to the control signal terminal of the gain control amplifier 32, and is also input to each arithmetic circuit.

As shown in FIG. 6, the image signal obtained from the sample and hold circuit 31 is generated every period T0 of the start signal supplied from the timing control circuit 41 to the one-dimensional image sensor 21, and is an image signal within the circumference XA To. The signal generation period T corresponds to one scanning time of the speckle pattern by the one-dimensional image sensor 21.

The image signal from the sample hold circuit 31 is input to the average level calculation circuit 52 of the calculation circuit 51.

The frequency divider 42 of the timing control circuit 41 divides the image signal generation period T into a plurality of regions, and inputs the divided timing signals to the average level calculation circuit 52.

The average level calculation circuit 52 divides the image signal per scan into a plurality of regions based on the division timing signal of the frequency divider 42, and calculates the average signal level for each region.

The display control circuit 53 outputs a monitor signal M to the indicator 62 based on the average signal level for each area determined by the average level calculation circuit 52.

54 is a changeover switch for changing the display of the indicator 62, and the amount of light received by the one-dimensional image sensor 21;
It is possible to switch between displays such as the tilt of the measurement head and the surface condition of the object to be measured.

When the amount of light received by the one-dimensional image sensor 21 is large, the image signal obtained from the sample and hold circuit 31 has a waveform as shown in FIG. 7(a).

Further, when the amount of light received by the one-dimensional image sensor 21 is appropriate, the image signal S becomes as shown in FIG. 7(b), and when the amount of light received is small, it becomes as shown in FIG. 7(C).

When a plurality of LEDs are provided as the indicator 62,
The average value of each divided area of the image signal is determined, and based on this, the magnitude of the amount of received light can be displayed based on the magnitude of the number of LEDs lit from the left end.

For example, as shown in FIG.
When L E D621 to 627 are provided, as shown in Fig. 7 (
When the light intensity is large in a), the display control circuit 53 controls all the LEs.
A monitor signal is output so that D621 to D627 are lit.

Further, when the amount of received light is small as shown in FIG. 7(c), only the LED 621 located at the left end is turned on as shown in FIG. 8(c).

When the amount of light received is appropriate and the image signal S as shown in FIG. 7(b) is obtained, the LE is displayed as shown in FIG. 8(b).
0621-624 are lit.

From this, you can adjust the mounting position of the measurement head to obtain the appropriate amount of light.

Furthermore, when the optical axis of the laser beam is perpendicular to the object to be measured, an image signal as shown in FIG. 9(b) is obtained, but when it is tilted to the left or right, As shown in FIG. 9(a) or FIG. 9(b), the waveform distribution is biased.

The inclination can be detected by dividing this into a plurality of regions and finding the average value of each divided region.

For example, if the distribution of the image signal is biased to the left as shown in FIG. 9(a), the LED 621 located at the left end of the plurality of LEDs is turned on and the If it is biased to the right as shown in Figure 9 (C), the 10th
As shown in Figure (c), the rightmost LED 627 is turned on.

When the inclination of the optical axis of the laser beam is appropriate and an image signal as shown in FIG. 9(b) is obtained, the LED 624 located at the center is turned on as shown in FIG. 10(C).

Of course, it is also possible to light up a plurality of LEDs depending on the inclination, and the display method is not particularly limited.

In this way, L located at the center of the indicator 62
By attaching the measuring head so that the ED624 lights up, an appropriate inclination of the optical axis can be set.

Depending on the surface condition of the object to be measured,
Image signals such as those shown in b) and (c) are obtained.

In the case of normal diffuse reflection, the image signal shows an average distribution in the generation period T as shown in FIG. 11(b), and the signal level of each divided area obtained from the average level calculation circuit 52 is averaged. .

From now on, as shown in FIG. 12(b), the indicator 6
2, LEDs 621 to 627 corresponding to each divided area
By outputting a monitor signal so that all the lights are turned on, it is possible to indicate that the surface condition of the object to be measured is an appropriate diffuse reflection.

In addition, when a peak occurs in the image signal as shown in Figure 11 (a) or (c), the surface of the object to be measured is in a state of specular reflection, and based on this, the area corresponding to the peak is determined. By lighting up the LED appropriately, it is possible to display that the object to be measured is a specular reflection, as shown in FIG. 12(a) or (c).

When measuring the inclination of the measuring head or the surface condition of the object to be measured, as shown in FIG. It is also possible to do so.

The number and arrangement of LEDs in the indicator 62 are not particularly limited to those in the embodiment, and the display method is not limited to those described above.

Further, it is also possible to display characters using a liquid crystal display board or the like as the indicator 62.

〔Effect of the invention〕

The speckle length meter monitor device according to the present invention is configured as described above, and monitors whether the amount of light is excessive or insufficient based on the distance to the object to be measured, the deviation of the received light signal due to the inclination of the optical axis of the laser generator, or the object to be measured. The surface condition, etc. of the sensor is detected and displayed on a display means, and the installation and position adjustment is facilitated.

[Brief explanation of the drawing]

Fig. 1 is a complaint-responsive view of a monitor device for a speckle length measuring meter according to the present invention, Fig. 2 is a partially cutaway exploded perspective view showing the structure of the measuring head of the speckle length measuring meter, and Fig. 3 is a view of the speckle length measuring meter. 4 is a waveform diagram of an image signal, FIG. 5 is a simplified block diagram of a monitor device of the present invention, FIG. 6 is a waveform diagram of an image signal, and FIG. 7 is a diagram based on changes in light intensity. Image signal waveform diagram, Figure 8 is an explanatory diagram of a display example of light amount, Figure 9 is an image signal waveform diagram based on the inclination of the optical axis of the laser beam, and Figure 10 shows the inclination of the optical axis of the laser beam. 11 is a waveform diagram of an image signal based on the surface condition of the object to be measured.
FIG. 2 is an explanatory diagram of a display example that displays the surface condition of the object to be measured. 1: Laser light generator, 2: One-dimensional image sensor, 3: Measuring circuit, 4: Timing control circuit, 5: Arithmetic circuit, 6: Display means, 7: Measuring head, 8: Measurement object, 11: Semiconductor laser unit, 12: beam exit aperture, 13: electronic cooling device, 21 one-dimensional image sensor, 22: Hanwha amplifier, 23: first stage amplifier, 31: sample hold circuit, 32 gain control amplifier, 33; binarization circuit, 34 : correlator, 35: microcomputer, 36: integrator, 41: timing control wholesale circuit, 42: frequency divider, 51: arithmetic circuit, 52: average level arithmetic circuit, 53: display control circuit, 54: changeover switch, 61: Display device, 62: Indicator, 71: Casing, 72: Rubber gasket, 73: Caher 7
4: Window. Patent applicant Keyence Corporation (α) <b'> (C) Figure (α) (shi) (Q) Figure 10 (α) (b) (C) Figure 72 Bl) cb+ (C) Figure Q Figure (b) (C) 1st/rI! J (a) c'o) CC)

Claims (1)

[Claims] 1) A laser beam generator that irradiates a laser beam onto the surface of a moving object to be measured, and converts a speckle pattern appearing on an observation surface opposite to the laser beam irradiation surface of the target object into an image signal. In a speckle length measuring meter equipped with a one-dimensional image sensor that performs photoelectric conversion and a measurement circuit that calculates the amount of movement of an object based on changes in the image signal as the object moves, a timing control circuit that generates a timing signal for dividing the distribution of the image signal obtained from the one-dimensional image sensor into a plurality of divided regions in the scanning direction of the one-dimensional image sensor; an arithmetic circuit that calculates the average level in each divided area of the image signal and creates a monitor signal; and a display means that displays the monitor signal according to the level of the monitor signal from the arithmetic circuit. A monitor device for a speckle length measuring device, characterized in that it displays at least one of an amount of light received by the one-dimensional image sensor, an inclination, and a surface condition of a target object according to a level. 2) The speckle length measuring device according to claim 1, further comprising a changeover switch capable of displaying at least two of the amount of light received by the one-dimensional image sensor, the inclination, and the surface state of the target object. 3) A monitor device for a speckle length measuring meter according to claim 1 or 2, wherein a plurality of LEDs arranged in a straight line are used as the display means.