JP5081559B2 - measuring device - Google Patents

Description

  The present invention relates to a measuring apparatus that irradiates an object with laser light and receives the reflected light to detect the displacement and shape of the object.

  Conventionally, as a technique for measuring the displacement and surface shape of an object, a technique for measuring the distance to the object by a triangulation method has been disclosed. For example, in the apparatus described in Patent Document 1, linear light is irradiated from a light projecting element to an object, and the reflected light is received by an imaging surface of an image sensor. And based on the irradiation image formed on the imaging surface of an image sensor, the surface shape of a target object is measured.

Specifically, the imaging surface is composed of a plurality of pixels arranged in a matrix, and the light reception signal of each pixel is read for each scanning line along the thickness direction of the irradiation image. Then, for each pixel on the read scanning line, a pixel having a peak light receiving signal level is specified, and the position is detected as a light receiving position. Thus, the surface shape of the part irradiated with the light of the object can be detected by performing the process of specifying the light receiving position on the scanning line of the pixel that becomes the peak for each scanning line.
JP 2006-133049 A

  However, in the case of the conventional technology as described above, when a portion with high reflectance and a portion with low reflectance are mixed on the surface of the object, the dynamic range of the image sensor is insufficient, and the position of the object is partially set. In some cases, it could not be detected. For example, if the amount of laser light emitted from the light projecting element is set to a low value according to the high reflectance part of the object, the received light amount is insufficient at the low reflectance part, and the detection value is buried in the noise. The light receiving position of the object cannot be detected. In addition, if the amount of laser light emitted from the light projecting element is set to be large in accordance with the portion where the reflectance of the object is low, the amount of received light is saturated at the portion where the reflectance is high, and the peak position of the received light amount cannot be detected . For this reason, there is a problem that if the reflectance of the object varies, the object cannot be measured stably.

  In addition, when the light emission amount and gain adjustment are performed by the feedback control of the light amount, it takes time for the feedback processing, so there is a problem that the image acquisition time by the image sensor becomes long and the time until the measurement value is confirmed becomes long. .

  The present invention has been made in view of such circumstances, and its purpose is to perform measurement of an object quickly and accurately even when a high-reflectance portion and a low-reflection portion are mixed in the object. An object of the present invention is to provide a laser sensor capable of

In order to solve the above-mentioned problem, the invention described in claim 1 includes a light projecting unit that irradiates a target with linear light, and a linear reflected light that is irradiated from the light projecting unit and reflected by the target. A two-dimensional imaging means for receiving light, a light-receiving processing means for outputting a light-receiving signal corresponding to the amount of light received for each scanning line of the two-dimensional imaging means, and a light-receiving signal inputted from the light-receiving processing means. A light receiving position detecting means for detecting a light receiving position, wherein the amount of light received by the two-dimensional imaging means is changed by changing the amount of light emitted by the light projecting means to a predetermined number of steps. And changing the level of the received light signal input to the received light position detecting means, changing the level of the received light signal by the changing means, and selecting the received light position detected at each level. For each scan line And control means for determining the light receiving position of the serial object, the control means, wherein when the plurality of light receiving positions are detected in one scan line by the light receiving position detecting means, the other detected in the same projection amount The average position of the scanning line with the light receiving position is the light receiving position on the scanning line.

According to this configuration, the level of the light receiving signal used for detecting the light receiving position is sequentially changed, and the light receiving position of the object is obtained based on the light receiving position detected at each level. This makes it possible to measure a portion with low reflectivity by increasing the level of the received light signal, and to measure a portion with high reflectivity by reducing the level of the received light signal. Even if a portion with high reflectance and a portion with low reflectance are mixed, measurement can be performed accurately. Moreover, since it is not necessary to perform feedback control, data can be obtained quickly.
In addition, even if the peak value of the light receiving position in one scanning line is not clear and the light receiving position cannot be determined, it is detected in another scanning line detected at the same light intensity as the data detected in that scanning line. The light receiving position is preferably estimated based on the data.

According to a second aspect of the present invention, in the case where a plurality of light receiving positions are detected in one scanning line due to a change in the level of the light receiving signal by the changing means, the control means calculates an average position of the plurality of light receiving positions. The light receiving position on the scanning line is used. According to this configuration, even when the peak value of the light receiving position in one scanning line is not clear and the light receiving position cannot be determined, the light receiving position is preferably estimated from the data detected in the scanning line.

According to a third aspect of the present invention, there is provided adjusting means for adjusting the light projection amount of the light projecting means changed by the changing means. According to this configuration, since the amount of change in the received light signal used for detecting the light receiving position is adjusted, the amount of change corresponding to the object can be used to measure the object more accurately.

According to a fourth aspect of the present invention, the light receiving position detecting means detects a light receiving position when the light receiving signal is within a predetermined range. According to this configuration, since the light receiving position detecting means detects the light receiving position only within a predetermined range, the process for detecting the light receiving position is performed at high speed.

According to a fifth aspect of the present invention, when the light receiving position detecting means does not detect the light receiving position, a notifying means for notifying the fact is provided. According to this configuration, when the light receiving position is not detected by the light receiving position detecting means, the fact is notified, so that the user can cope with the detection of the light receiving position.

  Therefore, according to the above-described invention, the object can be measured quickly and accurately even if the object has both a high reflectance portion and a low reflectance portion.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the measuring apparatus 10 according to the present embodiment is linear from the light projecting element 11 as the light projecting means to the work W as the object and the measurement table T on which the work W is placed. The laser beam is irradiated and the light reflected by the workpiece W is received by the image sensor 12. The surface of the measuring table T has a low reflectance, and the surface of the workpiece W is glossy and has a very high reflectance.

  Specifically, the light projecting element 11 is installed vertically above the workpiece W and the measuring table T as the objects. The laser light emitted from the light projecting element 11 is emitted through a slit plate (not shown) having a rectangular opening, and is thus placed on the workpiece W and the measuring table T as shown by the oblique lines in FIG. Irradiate linear light. The image sensor 12 is disposed obliquely above the measurement table T and receives reflected light from the measurement table T and the workpiece W.

  The measuring apparatus 10 is controlled centrally by the CPU 13, and the CPU 13 controls the light projection control circuit 14 that drives the light projecting element 11 and the light reception control circuit 15 that drives the image sensor 12. The CPU 13 is connected to a memory 13a.

  For the light projecting element 11, for example, a plurality of LDs (laser diodes) are used. The CPU 13 functions as a change unit and a light projection amount change unit, and controls the light projection control circuit 14 so that a current flows through a predetermined number of LDs constituting the light projecting element 11. The amount of laser light emitted from the element 11 is increased or decreased. For example, when increasing the light projection amount of the laser light emitted from the light projecting element 11, the CPU 13 increases the number of LDs through which a current flows and decreases the light projection amount of the laser light emitted from the light projecting element 11. In some cases, the number of LDs through which current flows is reduced. In the present embodiment, the CPU 13 switches the laser light emitted from the light projecting element 11 into two stages, that is, when the light projection amount is relatively large and when the light projection amount is relatively small.

  The image sensor 12 converts the received light from the workpiece W and the measuring table T into a received light signal corresponding to the received light amount for each scanning line, and outputs the received light signal. The direction of the scanning line of the image sensor 12 is along the direction orthogonal to the linear irradiation image formed by receiving the reflected light of the linear light projected by the light projecting element 11. For example, a CCD (Charge-Coupled Device) is used for the image sensor 12. The CCD individually accumulates signal charges proportional to the intensity of light received by the light receiving elements (photodiodes) that make up the surface, and sequentially transfers each signal charge (light receiving signal) accumulated in each light receiving element using a shift register. To do. In the present embodiment, the light receiving element constituting the CCD of the image sensor 12 corresponds to a two-dimensional imaging unit, and the shift register corresponds to a light receiving processing unit.

  The CPU 13 controls the light reception control circuit 15 so as to drive the CCD constituting the image sensor 12 in accordance with the timing of applying a current to the light projecting element 11. As a result, the reflected light from the workpiece W and the measuring table T of the laser light emitted from the light projecting element 11 is received by the image sensor 12, and the received light amount is converted into a received light signal and output to the CPU 13.

  The CPU 13 functions as a light receiving position detecting unit, and obtains a distribution diagram of the received light amount as shown in FIG. 3 for each scanning line of the image sensor 12 based on the light receiving signal input from the image sensor 12. And the light reception position X of the workpiece | work W is detected by detecting the position (pixel) used as the peak value in the distribution map. The CPU 13 can measure the displacement amount, shape, and the like of the workpiece W and the measuring table T as a whole by detecting the light receiving position on each scanning line.

  Further, as described above, the CPU 13 changes the light projection amount of the laser light emitted from the light projecting element 11 in two steps, that is, when the light projection amount is relatively large and when it is relatively small, thereby inputting from the image sensor 12. In addition to changing the level of the received light signal, the light receiving position is detected for each light projection amount, and the light receiving position in the entire work W and the measuring table T is obtained.

  Specifically, the CPU 13 writes the light receiving position detected by increasing the light projection amount of the light emitted from the light projecting element 11 in each scanning line to the memory 13 a and then irradiates from the light projecting element 11. The detected light receiving position is written in the memory 13a with the light projection amount reduced. When the light projecting amount from the light projecting element 11 is increased, the light receiving position of the portion having the low reflectance (measurement table T) is detected, and when the light projecting amount from the light projecting element 11 is decreased, the portion having the high reflectivity. The light receiving position of (work W) is detected. Then, the CPU 13 measures the entire workpiece W and the measuring table T by reading out from the memory 13a and synthesizing the light receiving positions detected by the respective light projection amounts in each scanning line.

  The CPU 13 detects the light receiving position when the light receiving signal input from the image sensor 12 is within a predetermined range. Specifically, as shown in FIG. 3, the light receiving position is detected within the range of the light receiving amounts R1 to R2.

  Further, the CPU 13 is connected to an operation unit 16 that outputs an electric signal to the CPU 13 for instructing various settings such as the amount of light emitted from the light projecting element 11 when operated by the user. A display unit 17 for displaying the measurement position detected by the CPU 13 based on the received light signal is connected.

  For example, a detection result as shown in FIG. 4 is displayed on the display unit 17. Since the linear laser light applied to the workpiece W and the measurement table T has different heights on the upper surface of the measurement table T and the upper surface of the workpiece W, the position (pixel) where the light is received by the light receiving surface of the image sensor 12 is determined. Different. Therefore, it is divided into line segments S1 to S3 and displayed on the display unit 17 corresponding to the position of the light receiving surface of the image sensor 12. The length of the line segment S2 in FIG. 4 corresponds to the width Ww of the workpiece W in FIG. 2, and the difference H between the line segments S1, S3 and the line segment S2 in FIG. This corresponds to the height Wh of W.

  More specifically, as shown in FIG. 5, the CPU 13 changes the light projection amount of the laser light emitted from the light projecting element 11 in each scanning line 21 to 34 and detects the light receiving position in each light projection amount. The CPU 13 displays the line segment S1 based on the light receiving positions Sa to Sd detected when the light projection amount is increased, and similarly, the line segment S3 based on the light reception positions Sk to Sn detected when the light projection amount is increased. Is displayed. Further, the CPU 13 displays the line segment S2 based on the light receiving positions Se to Sj detected when the light projection amount is reduced. Since the surface of the measuring table T has a low reflectance, the light receiving positions Sa to Sd and Sk to Sn are detected when the amount of projected light is high. The surface of the workpiece W has a high reflectance, so that the light receiving positions Se to Sj are projected. Detected when is low. And CPU13 displays line segment S1-S3 corresponding to the workpiece | work W and the measurement stand T by synthesize | combining the light reception position detected by each scanning line.

  Here, for example, since the scanning line 23 is a boundary portion between the measuring table T and the workpiece W, the light receiving position is detected both when the light projection amount is high and when the light projection amount is low. The light receiving positions Sc1 and Sc2 are detected. At this time, as shown in FIG. 6, the peak position of the distribution chart of the received light amount output at each light projection amount on the scanning line 23 is shifted. In this case, the CPU 13 obtains an average position between the light receiving position Sc1 detected when the light projection amount is high and the light reception position Sc2 detected when the light projection amount is low as the light reception position Sc on the scanning line 23. Similarly, two light receiving positions are detected for each of the scanning lines 24, 31, and 32, and the CPU 13 uses the average position as the light receiving position. Then, the CPU 13 displays the average position of the light receiving positions Sa to Sd on the display unit 17 as the line segment S1 and the average position of the light receiving positions Sk to Sn as the line segment S3.

  Further, the CPU 13 can adjust the amount of change in the light projection amount of the laser light emitted from the light projecting element 11. Specifically, when the operation unit 16 is operated by the user and instructed to change the light projection amount of the light emitted from the light projecting element 11, the CPU 13 increases or decreases the number of LDs through which current flows in the light projecting element 11. This makes it possible to adjust the light projection amount of the light emitted from the light projecting element 11. At this time, the operation unit 16 and the CPU 13 correspond to an adjustment unit that adjusts a light reception signal input to the CPU 13.

  If the light receiving position is not detected even if the light projection amount of the laser light emitted from the light projecting element 11 is changed, the CPU 13 displays this fact on the display unit 17 to notify the user. At this time, the CPU 13 and the display unit 17 correspond to notification means. For example, as shown in FIG. 7A, even if the light projection amount is increased, the light reception position is not detected when the light reception amount range output from the image sensor 12 to the CPU 13 is not included in the light reception amounts R1 and R2. . In such a case, the CPU 13 displays on the display unit 17 that the amount of light received by the image sensor 12 is too small. For example, the user operates the operation unit 16 to adjust the amount of laser light emitted from the light projecting element 11 to increase.

  For example, as shown in FIG. 7B, even if the light projection amount is reduced, the vicinity of the peak position of the received light amount output from the image sensor 12 to the CPU 13 exceeds the range of the received light amount R1 to R2. The light receiving position is not detected. In such a case, the CPU 13 displays on the display unit 17 that the amount of light received by the image sensor 12 is too large. For example, the user operates the operation unit 16 to adjust so as to reduce the light projection amount of the laser light emitted from the light projecting element 11.

  In addition, for example, when the peak position of the light reception signal output from the image sensor 12 to the CPU 13 is saturated and the light reception position is not detected even if the light projection amount is reduced, when the fact is displayed on the display unit 17, For example, the operation unit 16 is operated to adjust so that the light projection amount of the laser light emitted from the light projecting element 11 is reduced. Further, for example, even when the light projection amount is increased, the light reception signal output from the image sensor 12 to the CPU 13 is low and buried in noise, and when the light reception position is not detected, that fact is displayed on the display unit 17. For example, the user operates the operation unit 16 to adjust the amount of laser light emitted from the light projecting element 11 to increase.

Next, characteristic effects of the present embodiment will be described.
(1) In the measurement apparatus 10, the level of the received light signal used for detecting the light receiving position is changed by increasing / decreasing the light projection amount of the laser light emitted from the light projecting element 11, and the light received detected at each level. Based on the position, the light receiving positions of the workpiece W and the measuring table T are obtained. As a result, by increasing the level of the received light signal, it is possible to measure a portion having a low reflectance (measurement table T), and by decreasing the level of the amount of received light, measuring a portion having a high reflectance (work W). Even if a high-reflectance portion and a low-reflectance portion are mixed in the target object, accurate measurement can be performed.

  (2) The CPU 13 detects the light receiving position by increasing the amount of light emitted from the light projecting element 11, then detects the light receiving position by decreasing the amount of light projected, and synthesizes the light receiving positions, thereby combining the workpiece W. In addition, since the light receiving position of the measuring table T is synthesized, it is not necessary to perform feedback control. For this reason, data can be obtained quickly.

  (3) Since the light receiving position of the workpiece W and the measurement table T is detected when light of a light projection amount suitable for the reflectance of the surface of the workpiece W and the measurement table T is irradiated, the workpiece W and the measurement table T A result adapted to the reflectance of the surface can be obtained.

  (4) When a plurality of light receiving positions Sc1 and Sc2 are detected in one scanning line 23, the average position of the plurality of light receiving positions Sc1 and Sc2 is set as the light receiving position Sc. Even when the peak value of the position is not clear and the light receiving position cannot be determined, the light receiving position is preferably estimated from the data detected on the scanning line 23.

  (5) Since the light projection amount of the laser light emitted from the light projecting element 11 can be adjusted by the CPU 13, the work W and the measurement table T can be more accurately set by changing the amount corresponding to the work W and the measurement table T. It becomes possible to measure.

  (6) Since the CPU 13 detects the light receiving position only when the amount of received light input from the image sensor 12 is within the range of the received light amounts R1 to R2, the process for detecting the light receiving position is performed at high speed.

  (7) When the CPU 13 does not detect the light receiving position, the CPU 13 displays that fact on the display unit 17. If the light receiving position is not detected, the fact is notified, and the user can take action to detect the light receiving position.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the amount of light emitted is adjusted by changing the number of LDs to be projected for a plurality of LDs constituting the light projecting element 11, but the amount of current supplied to one LD May be adjusted to adjust the amount of light emitted. Moreover, it is good also as a structure provided with the optical element which can adjust the light quantity of transmitted light, such as a filter, between the light projection element 11 and a target object, and actuators, such as a motor which moves the optical element, as a light projection control means. .

  In the above embodiment, when a plurality of light receiving positions Sc1 and Sc2 are detected on one scanning line 23, the average position thereof is detected as the light receiving position Sc. An average position with respect to the light receiving positions Sa and Sb of the other scanning lines 21 and 22 detected when the light projection amounts of the laser beams are the same may be used as the light receiving position on the scanning line 23. In that case, as shown in FIG. 8, on the scanning line 23, pixels that are substantially the same as the light receiving positions Sa and Sb are obtained as the light receiving positions Sc. According to this configuration, the peak value of the light receiving position in one scanning line 23 is not clear, and even if the light receiving position cannot be determined, the data detected in the scanning line 23 and the other scanning lines 21 and 22 are detected. The light receiving position is preferably estimated based on the obtained data.

  In the above embodiment, a case has been described in which two light receiving positions Sc1 and Sc2 are detected for each light projecting amount changed in the light projecting element 11 in one scanning line 23. Even if the position is detected, an average position of the light receiving positions may be set as the light receiving position. Further, when two or more light receiving positions are detected in one scanning line, the light receiving positions in the scanning line may be obtained based on the light receiving positions.

  In the above-described embodiment, the light projection amount of the laser light emitted from the light projecting element 11 is sequentially changed to two steps, that is, a relatively large amount and a relatively small amount. The above may be changed. That is, the level of the received light signal input to the CPU 13 may be sequentially changed in three steps or more. In short, the level of the received light signal input to the CPU 13 may be changed so as to correspond to the object.

In the above embodiment, the CPU 13 detects the light reception position when the light reception signal is within the range of the light reception amounts R1 to R2, but the range for detecting the light reception position may not be limited.
In the above embodiment, the light projecting element 11 is not limited to the LD, and for example, an LED (light emitting diode) may be used.

  In the above embodiment, the light projecting element 11 is arranged vertically above the workpiece W and the measuring table T, and the image sensor 12 is arranged obliquely above the measuring table T. However, the shape of the workpiece W (the workpiece W is measured by the image sensor 12). If the reflected light is received at different positions according to the difference in height between the measuring table T and the measuring table T, the arrangement position is not limited to the above. For example, the image sensor 12 may be disposed vertically above the workpiece W and the measurement table T, and the light projecting element 11 may be disposed obliquely above the measurement table T.

  In the above embodiment, the image sensor 12 is not limited to the CCD, and for example, a CMOS may be used.

The schematic block diagram of a measuring apparatus. The perspective view of a workpiece | work and a measurement stand. The distribution diagram of the light reception amount of a light reception signal. Explanatory drawing of the detection result displayed on a display part. Explanatory drawing of the detection result displayed on a display part. The distribution diagram of the light reception amount of a light reception signal. (A), (b) is a distribution diagram of the amount of received light of the received light signal. Explanatory drawing of the detection result displayed on the display part of another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Measuring apparatus, 11 ... Light projection element as light projection means, 12 ... Image sensor as two-dimensional imaging means and light reception process means, 13 ... Light receiving position detection means, Change means, Control means, Light emission amount change means, Light reception Quantity changing means, adjusting means, CPU as notifying means, 16 ... operation part as adjusting means, 17 ... display part as notifying means, 21-34 ... scanning line, W ... work as object, T ... object As a measuring table, Sa to Sn, Sc1, Sc2, Sd1, Sd2, Sk1, Sk2, Sl1, Sl2, X ... light receiving position.

Claims (5)

Projecting means for irradiating the object with linear light, two-dimensional imaging means for receiving linear reflected light emitted from the light projecting means and reflected by the object, and scanning lines of the two-dimensional imaging means A measuring apparatus comprising: a light receiving processing means for outputting a light receiving signal corresponding to the amount of received light; and a light receiving position detecting means for detecting the light receiving position of the object based on the light receiving signal input from the light receiving processing means. And
By changing the amount of light emitted by the light projecting means to a predetermined number of steps, the amount of light received by the two-dimensional imaging means is changed, and the level of the received light signal input to the light receiving position detecting means is changed. Change means,
And changing the level of the light reception signal by the changing means, and a control means for obtaining the light receiving position of the object for each scanning line based on the selection of the light receiving position detected at each level,
In the case where a plurality of light receiving positions are detected in one scanning line by the light receiving position detecting means, the control means calculates an average position of the light receiving positions of other scanning lines detected with the same light projection amount with the scanning line. The measuring device characterized by the light receiving position. The measuring apparatus according to claim 1 ,
In the case where a plurality of light receiving positions are detected in one scanning line due to the change in the level of the light receiving signal by the changing means, the control means sets the average position of the plurality of light receiving positions as the light receiving position in the scanning line. A measuring device. The measuring apparatus according to claim 1 or 2 ,
A measuring apparatus comprising: an adjusting unit that adjusts a light projection amount of the light projecting unit that is changed by the changing unit. In the measuring device according to any one of claims 1 to 3 ,
The light receiving position detecting means detects a light receiving position when the light receiving signal is within a predetermined range. In the measuring device according to any one of claims 1 to 4 ,
When the light receiving position detecting means does not detect the light receiving position, the measuring apparatus is provided with a notifying means for notifying that effect.

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