TW202405374A - Measurement system - Google Patents

Abstract

A measurement system suitable for measuring the contour of an object. The measurement system includes multiple light sources, a calibration unit, a sensor, multiple alignment auxiliary units, and a calculation unit. The light sources are respectively used to project onto a part of the object, wherein there is an overlapping area when each of adjacent two of the light sources are projected onto the object. The calibration unit is set at the position corresponding to the object. The sensor is used to receive the contour information reflected when the light sources project onto the object. The alignment auxiliary units are respectively arranged at the position corresponding to the overlapping area in the calibration unit. The calculation unit is used to receive the contour information obtained by the sensor to calculate the contour of the object.

Description

Measurement system

The present invention relates to a measurement system, and in particular to a measurement system for measuring the contour of an object.

Generally, non-contact contour measurement uses a laser light source scanning method to form a profile by projecting a laser beam on the surface of the object to be measured, and then uses an optical sensor to sense the profile information and pass it through. Analysis to obtain the height information of the surface of the object being measured, that is, the contour information. In order to be able to determine the dimensions of the contour, a mapping is required from points in the plane of the optical sensor to points in the plane of light projected onto the object being measured, so that the coordinates in the plane of the optical sensor can be transformed into real-world coordinates . The process of obtaining this mapping is generally called calibration. This calibration is generally determined by means of measurements of a reference object due to the unknown scale of the mapping, the unknown projection distortion of the light plane relative to the optical sensor and the unknown distortion of the optical device.

However, in areas requiring high-precision and wide-field measurement, multiple sets of laser light sources and optical sensors are usually required to simultaneously measure the measured object in sections, because the information received by the optical sensors is affected by different lasers. The influence of the hardware conditions and setting conditions of the light source causes differences in the benchmarks. As a result, the accuracy of each set of contour information obtained by the optical sensor is somewhat different, and cannot be used directly in parallel. As a result, the overall contour information of the measured object cannot be measured. Know accurately.

An aspect of the present invention provides a measurement system suitable for measuring the contour of an object. The measurement system includes multiple light sources, calibration units, sensors, multiple alignment auxiliary units and calculation units. A plurality of light sources are respectively used to project onto a part of the object, wherein each two adjacent light sources have an overlapping area when projecting onto the object. The calibration unit is set to the position corresponding to the object. The sensor is used to receive the profile information reflected by the light sources when they are projected onto the object. A plurality of alignment auxiliary units are respectively disposed at positions corresponding to the overlapping areas in the calibration unit. The computing unit is used to receive the contour information obtained by the sensor to calculate the contour of the object.

In some embodiments, the calibration unit includes a plurality of zigzag portions, wherein each zigzag portion has a tooth tip and a tooth valley is formed between two adjacent zigzag portions.

In some embodiments, the alignment auxiliary unit includes two connected side portions and a tip portion disposed in the middle of the two side portions, wherein the side portion can be disposed on one side of the zigzag portion of the calibration unit.

In some embodiments, the height of the tip is not equal to the height of the tooth tip.

In some embodiments, the calculation unit will perform correlation coefficient calculation on the data of the two contour information of the overlapping area to obtain the joint position of the contour information obtained by the two light sources corresponding to the overlapping area.

In some embodiments, the calculation unit calculates the correlation coefficient through equation (1); …(1) Among them, X _i is the position of the object’s outline information on the X axis, Z _i is the height of the object’s outline information corresponding to the X _i position, is the average number from X ₁ to X _n , is the average number from Z ₁ to Z _n .

In some embodiments, the calculation unit sets the position of the data with the highest correlation coefficient among the data of the two contour information in the overlapping area as the joining position.

In some embodiments, the light sources are laser light.

To sum up, through the alignment auxiliary unit, it is possible to know the overlapping area where two adjacent light sources are projected onto the measurement object, and then by calculating the correlation coefficient on the contour information of the overlapping area, the values obtained by the two adjacent light sources can be obtained at the merging position of the contour information, and then perform merging processing to obtain the overall contour information of the measured object.

In order to make the above and other objects, features, and advantages of the present invention more apparent and understandable, preferred embodiments of the present invention will be described in detail below along with the accompanying drawings.

Please refer to Figure 1 , which is a schematic diagram of a measurement system according to an embodiment of the present invention. The measurement system 10 includes a plurality of light sources 12 and sensors 14 . The light source 12 is suitable for illuminating the measuring object 16 with an incident light plane 18 , which may also be referred to as a sheet of light. The sensor 14 is adapted to detect light 20 reflected from the measurement object 16 and to generate an image based on this reflected light 20 . In an embodiment, the measurement system 10 further includes a computing unit 24 adapted to store and/or analyze the images recorded by the sensor 14 .

In one embodiment, the light source 12 is laser light, so that the light plane 18 forms a laser plane.

Please refer to Figure 2 as well. Figure 2 is a schematic diagram of a measurement system 10' with a calibration unit according to an embodiment of the present invention. As shown in Figure 2, a calibration unit 32 is also included in the measurement system 10' which is introduced into a corresponding position in the light plane 18. In one embodiment, the calibration unit 32 includes a plurality of zigzag portions 34 , wherein each zigzag portion 34 has a tooth tip, and a tooth valley is formed between two adjacent zigzag portions 34 . In this manner, the calibration unit 32 includes a plurality of points between which relative distances have been predetermined. Through the calibration unit 32 , the calculation unit 24 can accurately calculate the profile information of the measurement object through the reflected light information received by the sensor 14 .

As mentioned previously, the plurality of light sources 12 of the measurement system 10 are projected onto a part of the measurement object 16 respectively, and the reflected light is received through the sensor 14 to obtain the contour information of each part of the measurement object 16. This information can be transmitted to the computing unit 24 to analyze and generate corresponding contour images. However, due to the influence of the hardware conditions and setting conditions of each light source 12, the reference is different, resulting in the accuracy of each set of contour information obtained by the optical sensor being somewhat different, and cannot be directly used in parallel.

Please refer to Figures 3 and 4 together. Figure 3 is a schematic diagram of an alignment auxiliary unit according to an embodiment of the present invention. Figure 4 is a schematic diagram of a measurement system 10'' according to an embodiment of the present invention. As shown in FIG. 4 , the measurement system 10 ″ also includes a plurality of alignment auxiliary units 40 (only one is shown in the figure). The alignment auxiliary units 40 are located in the overlapping area where the adjacent light sources 12 are projected onto the calibration unit 32 . On the tooth valley. In one embodiment, as shown in FIG. 3A , the alignment auxiliary unit 40 has two connected side portions 41 and a tip portion 43 disposed in the middle of the two side portions. The edge of the alignment auxiliary unit 40 can be completely attached to one side of the zigzag portion 34 of the calibration unit 32 , so that the alignment auxiliary unit 40 can be completely and stably disposed on the tooth shell of the calibration unit 32 . In one embodiment, the height of the tip 43 is not equal to the height of the tooth tip of the sawtooth-shaped portion 34 . Preferably, the height of the tip 43 is much smaller than the height of the tooth tip, as shown in FIG. 4 , so that the calibration unit 32 An irregular shape is formed in the regularly arranged zigzag portions 34 , and this irregular shape is located in the overlapping area where two adjacent light sources 12 project onto the calibration unit 32 . However, the present invention is not limited to this. The shape of the alignment auxiliary unit 40 can be designed correspondingly according to the shape of the calibration unit, as long as the originally regularly arranged calibration units can form an obviously irregular and easily identifiable shape in the overlapping area. That’s it. In this way, when the calculation unit 24 analyzes the contour information, it can know through the information provided by the alignment auxiliary unit 40 that the position corresponding to the alignment auxiliary unit 40 is the overlapping area projected by the two light sources 12. This area That is the location where the contour information will be merged later.

Please refer to Figure 5A , which illustrates the outline information of the overlapping area obtained by the measurement system 10 ″ in Figure 4 . Figure 5A(a) is the outline information of the overlapping area obtained through the light source 12 on the left side of the measurement system 10", and Figure 5A(b) is the overlapping area obtained through the light source 12 on the right side of the measurement system 10". outline information. Since the two pieces of contour information are obtained through different light sources, the information standards of the two are different and must be calibrated before they can be connected. In one embodiment, the calculation unit 24 records the contour information received by the sensor in an independent coordinate system, and then performs data normalization on the contour information to obtain the data in Figure 5A. Next, the calculation unit 24 calculates the correlation coefficient of the data in the two charts through equation (1). _… (1) Among them _, Axis coordinates (which represent the height of the measured object's contour information corresponding to the X _i position), is the average number from X ₁ to X _n , is the average number from Z ₁ to Z _n .

The correlation coefficient r is the common variable of X and Z divided by the product of the standard deviation of X and the standard deviation of Z. The common variables of X and Z can be expressed by formula (2), the standard deviation of X can be expressed by formula (3), and the standard deviation of Z can be expressed by formula (4). Therefore, formula (1) can be obtained by dividing formula (2) by the product of formula (3) and formula (4). …(2) …(3) …(4)

Specifically, the calculation unit 24 can compare the data of each position in Figure 5A (a) with each position in Figure 5A (b) corresponding to the same position in Figure 5A (a) (ie, on the same X coordinate). The correlation coefficient between the two is calculated from the data, where each data represents the measured height of one position of the object's outline. Next, the calculation unit 24 shifts all the data in Figure 5A (a) by one unit (for example, moves one X coordinate unit to the right), and then compares each shifted data in Figure 5A (a) with Figure 5A (b). Correspond to each data at the same position after displacement in Figure 5A (a) and calculate the correlation coefficient between the two, and so on until all possible correlation coefficients are completed. Among all the calculated correlation coefficients, the higher the correlation coefficient, the closer the data of the two charts are to the joint position. Therefore, after the calculation of the correlation coefficients of all data is completed, the data with the largest correlation coefficient is the position that can be connected (that is, the same position in Figure 5A (a) and Figure 5A (b)). As shown in Figure 5B, Figure 5B illustrates the complete contour information obtained after concatenating the contour information in Figure 4A. The left half corresponds to the contour information projected through the left light source 12, and the right half Corresponds to the contour information projected through the right light source 12 .

It can be seen from the above embodiments that through the alignment auxiliary unit provided by the present invention, the overlapping area projected by two adjacent light sources onto the measurement object can be known, and then by calculating the correlation coefficient on the outline information of the overlapping area, it can be obtained The combined position of the contour information obtained through two adjacent light sources is then combined to obtain the overall contour information of the measured object.

Although the present invention has been disclosed in preferred embodiments, they are not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be subject to the scope of the patent application attached.

10, 10’, 10’’: measuring system 12:Light source 14: Sensor 16: Measuring objects 18: Incident light plane 20: Reflected light 24:Computing unit 32:Calibration unit 34:Zigzag part 40: Alignment auxiliary unit 41:Border 43:Tip

Figure 1 is a schematic diagram of a measurement system according to an embodiment of the present invention;

Figure 2 is a schematic diagram of a measurement system with a calibration unit according to an embodiment of the present invention;

Figure 3 is a schematic diagram of an alignment auxiliary unit according to an embodiment of the present invention;

Figure 4 is a schematic diagram of a measurement system according to an embodiment of the present invention;

Figure 5A illustrates the contour information of the overlapping area obtained by the measurement system in Figure 4; and

Figure 5B shows the complete outline information obtained after concatenating the outline information in Figure 5A.

10”: Measuring system

12:Light source

14: Sensor

20: Reflected light

24:Computing unit

34:Zigzag part

41:Border

43:Tip

Claims (8)

A measurement system suitable for measuring the contour of an object, including: A plurality of light sources are respectively used to project onto a part of the object, wherein each two adjacent light sources have an overlapping area when projecting onto the object; A calibration unit, set at a position corresponding to the object; A sensor for receiving the profile information reflected by the light sources when they are projected onto the object; A plurality of alignment auxiliary units are respectively arranged at positions corresponding to the overlapping areas in the calibration unit; and A calculation unit is used to receive the outline information obtained by the sensor to calculate the outline of the object. The measurement system as claimed in claim 1, wherein the calibration unit includes a plurality of zigzag portions, wherein each zigzag portion has a tooth tip, and a tooth valley is formed between two adjacent zigzag portions. The measurement system of claim 2, wherein the alignment auxiliary unit includes two connected sides and a tip disposed in the middle of the two sides, wherein the side can be placed on the zigzag part of the calibration unit on one side. The measurement system as claimed in claim 3, wherein the height of the tip is not equal to the height of the tooth tip. The measurement system as described in claim 1, wherein the calculation unit will perform correlation coefficient calculation on the data of the two contour information of the overlapping area to obtain the joint position of the contour information obtained by the two light sources corresponding to the overlapping area. The measurement system as described in claim 5, wherein the calculation unit calculates the correlation coefficient through formula (1); …(1) Among them, X _i is the position of the object’s outline information on the X axis, Z _i is the height of the object’s outline information corresponding to the X _i position, is the average number from X ₁ to X _n , is the average number from Z ₁ to Z _n . The measurement system as described in claim 6, wherein the calculation unit sets the position of the data with the highest correlation coefficient among the data of the two contour information of the overlapping area as the parallel position. The measurement system as claimed in claim 1, wherein the light sources are laser lights.