Patent Publication Number: US-8970833-B2

Title: Method and system of detecting tilt angle of object surface and method and system of compensating the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 101149578, filed on Dec. 24, 2012. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     TECHNICAL FIELD 
     The disclosure relates to a method and a system of detecting a tilt angle of an object surface and a method and a system of compensating the same. 
     BACKGROUND 
     In nowadays, when purchasing consumer products, consumers not only consider the functionalities but also gradually pay attention to the product appearances, such that processing molding methods of appearance elements of the consumer products become diversified and important. Accordingly, applications and demands for performing processing procedures, such as cutting, welding, drilling, mold micro-machining and so forth, on a non-plane object or a workpiece become more widespread. 
     A processing machine performs a positioning process by using a laser light source to project on the workpiece, and enables the processing equipment to perform a processing procedure according to positioning point. If a processing surface is a curved or a non-plane surface, the pros and cons of the processing effect will be directly influenced by a relationship between a focal-point position of the laser light source and a tilt angle on the processing surface. If an operator desires to perform an automated processing procedure on workpieces of the same type by the processing machine, there are few differences of a distance and an angle between each workpiece and each processing equipment (e.g. an automated robot arm), which leads to errors occurring in each operation. Further, even though the processing machine would dutifully perform the processing procedure according to the data inputted by the operator, the stereoscopic workpieces still have their own tolerances, and as a result, the errors occur. 
     Accordingly, manufacturers would like an apparatus capable of detecting relations between laser light spots and the tilt angles on the workpiece surfaces to be installed on the processing machine, such that the processing machine may perform the processing procedures on the workpieces more accurately. Currently, devices for determining the tilt angle on the workpiece may be implemented by various manners. A first manner is to project a laser light source on a workpiece and monitor a distance and a tilt angle between the workpiece and the processing machine according to the reflection of the laser light source. However, such reflective measurement is limited by the roughness and reflectivity of the processing surface and requires a more tilting angle for the laser light to reflect. Additionally, the reflective measurement is incapable of simultaneously measuring tilt angles of two dimensions, and therefore, more time-consuming. A second manner is to detect the distance between the processing equipment and the workpiece by using a sensing capacitor; however, such capacitive measurement is influenced by environmental factors (e.g. degrees of a temperature and humidity) and thus, requires a compensating process and is difficult to be applied to non-metal workpieces. 
     SUMMARY 
     The disclosure relates to a method and a system of detecting a tilt angle of an object surface and a method and a system of compensating the same, by which positional relationships among a plurality of light spots on the object surface are captured by using an image sensing device and accordingly calculated. The detection and compensation system are not limited to the material composition of the object, the reflectivity and flatness of the object surface and capable of simultaneously measuring tilt angles in two dimensions on the object surface. 
     According to an exemplary embodiment of the disclosure, a method of detecting a tilt angle of an object surface is introduced. The method includes the following steps. A plurality of light beams are projected by a light source device to an object surface, wherein a number of the light beams is greater than or equal to 3. An image of the object surface is captured so as to obtain a plurality of light spots generated on the object surface by the light beams. A vertical distance between the light source device and the object surface is adjusted to execute a focus program so as to gather the light spots in a focal point on the object surface. And, the vertical distance is adjusted, and a correction angle between the light beams and the object surface is calculated according to the light spots. 
     According to another exemplary embodiment of the disclosure, a system of detecting a tilt angle of an object surface is introduced. The system includes a light source device, an image capture device, an axial direction controller, an object carrying device and a computing device. The light source device projects a plurality of light beams to the object surface, wherein a number of the light beams is greater than or equal to 3. The image capture device captures an image of the object surface. The axial direction controller is coupled to the light source device and adjusts angles of the light beams of the light source device projecting to the object surface. The object carrying device adjusts a vertical distance between the light source device and the object surface. And, the computing device is coupled to the image capture device and receives the image so as to obtain a plurality of light spots generated on the object surface by the light beams. The computing device calculates a correction angle between the light source device and the object surface according to the light spots. 
     According to still another exemplary embodiment of the disclosure, a method of compensating a tilt angle of an object surface is introduced. The method includes the following steps. A plurality of light beams are projected by a light source device to an object surface, wherein a number of the light beams is greater than or equal to 3. An image of the object surface is captured so as to obtain a plurality of light spots generated on the object surface by the light beams. A vertical distance between the light source device and the object surface is adjusted to execute a focus program so as to gather the light spots in a focal point on the object surface. And, a correction angle and the vertical distance between the light source device and the object surface are adjusted and calculated according to the light spots. 
     Further, according to yet another exemplary embodiment of the disclosure, a system of compensating a tilt angle of an object surface is introduced. The system includes a light source device, an image capture device, an axial direction controller, an object carrying device and a computing device. The light source device projects a plurality of light beams to an object surface, wherein a number of the light beams is greater than or equal to 3. The image capture device captures an image of the object surface. The axial direction controller is coupled to the light source device and adjusts angles of the light beams of the light source device projecting to the object surface. The object carrying device is configured to adjust a vertical distance between the light source device and the object surface. The computing device is coupled to the image capture device and receives the image so as to obtain a plurality of light spots generated on the object surface by the light beams. The computing device executes a focus program according to the light spots, adjusts the vertical distance through the axial direction controller so as to gather the light spots in a focal point on the object surface and calculates and adjusts a correction angle and the vertical distance between the light source device and the object surface according to the light spots. 
     To sum up, in the method and the system of detecting the tilt angle of the object surface as well as the method and the system of compensating the same introduced by the disclosure, a positional relationship among a the plurality of light spots is obtained by the coaxially disposed light source device and the image sensing device, and a spatial relationship (such a distance and a tilt angle) between a laser light source (or a processing equipment) and the object surface is adjusted through algorithm calculations, such that the detection device is not limited to the material composition of the object, the reflectivity and flatness of the object surface and capable of simultaneously measuring the tilt angles in two dimensions on the object surface. In addition, in the compensation method and system introduced by the exemplary embodiments of the disclosure, a processing equipment may be further installed, and the relative spatial relationship between the processing equipment and the object surface is adjusted according to the tilt angle obtained through the calculations. Accordingly, an effect and quality of processing the object may be enhanced so as to facilitate in industrial equipments which perform laser processing procedures. 
     In order to make the disclosure more comprehensible, several exemplary embodiments accompanied with figures are described in detail below to further describe the disclosure in details. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments and, together with the description, serve to explain the principles of the disclosure. 
         FIG. 1  is a schematic diagram illustrating a system of detecting a tilt angle of an object surface according to an exemplary embodiment of the disclosure. 
         FIG. 2  is a flowchart illustrating a method of detecting a tilt angle of an object surface according to an exemplary embodiment of the disclosure. 
         FIG. 3  is a detailed flowchart of step S 230  depicted in  FIG. 2 . 
         FIGS. 4A and 4B  are schematic diagrams illustrating an arrangement of each of the light spots when a number of the light beams is 4. 
         FIG. 5  is a detailed flowchart of step S 240  depicted in  FIG. 2 . 
         FIG. 6  is a schematic diagram illustrating an arrangement of each of the light spots when the number of the light beams is 5. 
         FIG. 7  is a schematic diagram illustrating the object surface on the connection of the light spots P 2 , P 5  and P 4  to calculate the tilt angle when the number of the light beams is 5. 
         FIG. 8  is a schematic diagram illustrating an arrangement of each of the light spots when the number of the light beams is 4. 
         FIG. 9  is a schematic diagram illustrating the object surface on the connection of light spots P 1  and P 2  to calculate the tilt angle when the number of the light beams is 4. 
         FIG. 10  is a schematic diagram illustrating an arrangement of each of the light spots when the number of the light beams is 3. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     Reference will now be made in detail to the exemplary embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Referring to  FIG. 1 ,  FIG. 1  is a schematic diagram illustrating a detecting system  100  of a tilt angle of an object surface  170  of an object  160  according to an exemplary embodiment of the disclosure. The detecting system  100  may be installed in processing equipment, such as a robot arm installed for laser welding and laser cutting various types of workpieces in vehicle production and is applicable to various types of equipments of producing curved-surface objects, but the disclosure is not limited thereto. The processing equipments may position a processing position by the detecting system  100  using a laser light source. 
     The detecting system  100  of the present exemplary embodiment includes a light source device  110 , an image capture device  120 , an axial direction controller  130 , an object carrying device  150  and a computing device  140 . The light source device  110  projects a plurality of light beams LB 1 ˜LB 4  to the object surface  170  of the object  160 . The object  160  may be a plane workpiece, a curved-surface workpiece or any other non-plane workpiece, such as a mold, a vehicle part, a product housing, a glass panel and so forth. The light source device  110  may be implemented by a transmitter of a laser light source with a visible light wavelength, such that the image capture device  120  may implement capturing an image IM by a camera with a generally-used resolution. Those that apply the present exemplary embodiment may also be implemented by a transmitter of a laser light source with a invisible light wavelength; however, the image capture device  120  in this case requires a camera having a corresponding specification to capture the image IM. Thus, the image IM may have a plurality of light spots P 1 ˜P 4  formed on the object surface  170  by the light beams LB 1 ˜LB 4 . Each of the light beams LB 1 ˜LB 4  of the light source device  110  has a fixed emitting angle and is configured relatively. Thus, if an light beam emitting surface  115  of the light source device  110  is separated from the object surface  170  by a specific vertical distance Z, the light spots P 1 ˜P 4  generated by the light beams LB 1 ˜LB 4  mat be focused on a same point, no matter whether the light beam emitting surface  115  is parallel to the object surface  170  or not. 
     It is to be mentioned that the detecting system  100  requires the light spots P 1 ˜P 4  formed on the object surface  170  to calculate a tilt angle between the object surface  170  and the light source device  110 . Thus, when a number of the light beams is 2, the detecting system  100  may detect a tilt angle on a single axial (e.g. a one-dimensional line segment) on the object surface  170 . When the number of the light beams is greater than 3, the detecting system  100  may detect a tilt angle on two axes (i.e. a two-dimensional surface) on the object surface  170 . Corresponding calculation methods and mechanisms of the detecting system  100  in the scenarios where the number of the light beams is 3, 4 and 5 respectively will be described in the following exemplary embodiments. Additionally, an arrangement of the light beams presents a specific geometric shape on the same horizontal plane, such that the tilt angle of the object surface may be calculated. Those apply the present exemplary embodiment may know from the exemplary embodiments illustrated by the disclosure about the related implementations in the scenarios where the number of the light beams is equal to or greater than 3. A description in related to the exemplary embodiment of four light beams LB 1 ˜LB 4  and four light spots P 1 ˜P 4  generated thereby will be made with reference to  FIG. 1 . 
     The image capture device  120  captures an image located adjacently to the object surface  170  so as to obtain a plurality of light spots P 1 ˜P 4  on the object surface  170 . In the present exemplary embodiment, the image capture device  120  is coaxially disposed with the light source device  110 . Namely, the image capture device  120  is disposed at a position same as or adjacent to the light source device  110 , and these two devices are simultaneously controlled by the axial direction controller  130  to rotate and move with respect to the same axial center. Thus, the image capture device  120  keeps obtaining the light spots P 1 ˜P 4  generated by the light source device  110 . In other exemplary embodiments, the image capture device  120  may also be independently disposed without being coaxially disposed with the light source device  110 . 
     The axial direction controller  130  is coupled to the light source device  110  and may also be coupled to the image capture device  120  simultaneously. The axial direction controller  130  obtains an axial-direction adjustment signal AS from the computing device  140  so as to adjust angles of the light beams LB 1 ˜LB 4  of the light source device  110  projecting to the object surface  170 . If the image capture device  120  is coaxially disposed with the light source device  110 , the axial direction controller  130  simultaneously adjusts angles and spatial positions of the image capture device  120  and the light source device  110 . 
     The object carrying device  150  is used to carry the object  160  and obtains a position adjustment signal PS from the computing device  140  so as to adjust a vertical distance between the light source device  110  and the object surface  170 . In the present exemplary embodiment, the light source device  110  is disposed vertically on the object  160  so as to project the light beams LB 1 ˜LB 4  and accurately measure a tilt angle of the object surface  170  relative to the light source device  110 . The object carrying device  150  may be a carrier of the processing equipment and may perform operations, such as vertical uplift, vertical descent, rotation with an angle, horizontal movement and so forth, on the object  160  so as to finely adjust the computing device  140  during object positioning or processing. 
     The computing device  140  is coupled to the image capture device  120 , the axial direction controller  130  and the object carrying device  150 . The computing device  140  receives the captured image IM by the image capture device  120  and resolves the image IM through an image algorithm so as to obtain the light spots P 1 ˜P 4  generated on the object surface  170  by the light beams LB 1 ˜LB 4  therefrom. Accordingly, the computing device  140  may calculate a correction angle to be finely adjusted between the light source device  110  and the object surface  170  according to the light spots P 1 ˜P 4 . Thus, the detecting system  100  of the disclosure detects the plurality of light spots P 1 ˜P 4  on the object surface  170  by the image capture device  120  and adjust an error of laser positioning by the computing device  140  using a corresponding calculation mechanism, without being limited to the material, surface reflectivity and flatness adopted by the object  160 . Positions of the light spots P 1 ˜P 4  detected by the image capture device  120  are in a two-dimensional distribution, and thus, a tilt angle in two dimensions may be simultaneously measured. For example, a tilt angle on the X axis and the Y axis on the object surface  170  may be simultaneously measured. 
     In the exemplary embodiments of the disclosure, the computing device  140  of the detecting system  100  may further execute a focus program according to the positions of the light spots P 1 ˜P 4 , by which a vertical distance Z between the light source device  110  and the object surface  170  is adjusted through the axial direction controller  130  so that the light spots P 1 ˜P 4  of the object surface  170  may be focused on the focal point for accurate laser positioning. The computing device  140  of the present exemplary embodiment determines whether the light spots P 1 ˜P 4  coincide in the focal point through the image IM. When the light spots do not coincide in the focal point, the computing device  140  repeatedly adjusts the vertical distance Z and calculates an interval between each of the light spots, such that the light spots P 1 ˜P 4  coincide in the focal point. The description in connection with the enabling method and process of the focus program will be made with reference to  FIG. 2 . 
       FIG. 2  is a flowchart illustrating a method of detecting a tilt angle of an object surface according to an exemplary embodiment of the disclosure, which is implemented by adopting the detecting system  100  depicted in  FIG. 1 . Referring to  FIG. 2  with  FIG. 1 , in step S 210 , the detecting system  100  projects a plurality of light beams (e.g. the light beams LB 1 ˜LB 4  depicted in  FIG. 1 ) to the object surface  170  by the light source device  110 . In the present exemplary embodiment, the number of the light beams may be greater than or equal to 3. When the number of the light beams is 2, the detecting system  100  may detect a tilt angle on a single axial (e.g. a one-dimensional line segment) on the object surface  170 . When the number of the light beams is greater than 3, the detecting system  100  may detect a tilt angle on two axes (i.e. a two-dimensional surface) on the object surface  170 . In step S 220 , the computing device  140  captures an image IM of the object surface  170  by the image capture device  120  and resolves the image IM so as to obtain light spots P 1 ˜P 4  generated on the object surface  170  generated by the light beams LB 1 ˜LB 4 . 
     In step S 230 , the computing device  140  utilizes the object carrying device  150  to adjust the vertical distance Z between the light source device  110  and the object surface so as to execute the focus program. As such, the light spots P 1 ˜P 4  on the object surface  170  are gathered in the focal point. After executing the focus program, it represents that the light beam emitting surface  115  of the light source device  110  is apart from the object surface  170  by the specific vertical distance Z, and thus, the light beam emitting surface  115  is different from the object surface  170  by only the tilt angle. Accordingly, in step S 240 , the computing device  140  adjusts the vertical distance Z by the object carrying device  150 , obtains the two-dimensional distribution of the positions of the light spots P 1 ˜P 4  on the object surface  170  by the image capture device  120  and calculates the correction angle between the light beams LB 1 ˜LB 4  (i.e. the light beam emitting surface  115 ) and the object surface  170  according to the positions of the light spots. In brief, when executing the focus program, whether the light spots coincide in the focal point is determined first. When the light spots do not coincide in the focal point, the light spots are coincided in the focal point by adjusting the vertical distance and calculating the interval between each of the light spots. 
     Herein, the focus program executed by the computing device  140 , i.e. step S 230  depicted in  FIG. 2  will be described in detail.  FIG. 3  is a detailed flowchart of step S 230  depicted in  FIG. 2 .  FIGS. 4A and 4B  are schematic diagrams illustrating an arrangement of each of the light spots when a number of the light beams is 4. When the number of the light beams is equal to 4, an arrangement of the first through the third light spots P 1 ˜P 3  generated by the light beams LB 1 ˜LB 3  presents an equilateral triangle  410  or  420  on the same surface, as shown in  FIGS. 4A and 4B  of the disclosure. The fourth light spot P 4  generated by the light beam LB 4  is arranged in a gravity center position of the equilateral triangle  410  or  420 . Referring to  FIGS. 4A and 4B  with  FIG. 1  and  FIG. 2 . In step S 310 , the computing device  140  captures the image IM by the image capture device  120  so as to acquire a two-dimensional distribution of the light spots P 1 ˜P 4  on the object surface  170  ( FIG. 4A ). In step S 320 , the computing device  140  measures a plurality of first intervals between each of the light spots by using the two-dimensional distribution. For example, the computing device  140  may measure a first interval L 12  between the light spots P 1  and P 2 , a first interval L 23  between the light spots P 2  and P 3 , a first interval L 13  between the light spots P 1  and P 3  and first intervals L 14 , L 24  and L 34  between the light spot P 4  and each of the light spots P 1 ˜P 3  by the light spots P 1 ˜P 4  presented in  FIG. 4A . 
     In step S 330 , the computing device  140  determines whether all the first intervals (i.e. the intervals L 12 , L 13 , L 14 , L 24  and L 34 ) are equal to 0. When all the first intervals are 0, the light spots are determined as coinciding in the focal point, which represents that the light spots P 1 ˜P 4  are focused on the same point. Accordingly, step S 370  is entered to finalize the focus program. Otherwise, when none of the first intervals is 0, step S 332  is entered, where the computing device  140  controls the object carrying device  150  to adjust the vertical distance Z along a first vertical direction. For example, the object surface  170  may be uplifted to shorten the vertical distance Z. The first vertical direction is from the object  160  facing toward the light source device  110 . 
     In step S 334 , the computing device  140  acquire again the two-dimensional distribution illustrated in  FIG. 4B  by using the image capture device  120  to measure a plurality of second intervals between each of the light spots P 1 ˜P 4 . For example, the computing device  140  may measure a plurality of second intervals M 12 , M 23 , M 13 , M 14 , M 24  and M 34  by using the light spots P 1 ˜P 4  presented in  FIG. 4B . 
     In step S 336 , if all the second intervals are equal to 0, it represents that the light spots P 1 ˜P 4  are focused on the same point, and thus, step S 370  is entered to finalize the focus program. Otherwise, when all the second intervals are not equal to 0, step S 338  is entered, and the computing device  140  calculates a difference between each of the first intervals (L 12 , L 13 , L 14 , L 24  and L 34 ) and each of the corresponding second intervals (M 12 , M 23 , M 13 , M 14 , M 24  and M 34 ). 
     In step S 340 , the computing device  140  determines whether the differences are positive values. When the differences are positive values, it represents that the interval between each of the light spots is gradually enlarged. Namely, the height of the object  160  is required to decrease to elongate the vertical distance Z, such that each of the light spots would approach to each other for being focused. Accordingly, step S 350  is entered, and the computing device  140  configures each of the second intervals as each of the corresponding first intervals. For example, the second interval M 12  is configured as the first interval L 12 , and the vertical distance Z is adjusted along a second vertical direction reversed to the first vertical direction, for example, by decreasing the height of the object  160  to elongate the vertical distance Z. Then, step S 334  is entered from step  350 , and the second interval between each of the light spots is measured. Then, steps S 334 ˜S 340  are repeated to adjust the vertical distance Z, such that the light spots P 1 ˜P 4  are gathered in the same focal point. On the other hand, in step S 340 , when the computing device  140  determines that the differences are negative values, it represents that the interval between each of the light spots is gradually decreased. Namely, the adjustment of the vertical distance Z along the first vertical direction is correct, but should be continued. Thus, step S 360  is entered, and the computing device  140  configures each of the second intervals as each of the corresponding first intervals and continues to adjust the vertical distance Z along the first vertical direction. Then, step S 334  is entered from step S 360 , where the second interval between each of the light spots is measured and steps S 334 ˜S 340  is repeated to finalize the focus program. 
     Herein, how the detecting system  100  calculates the correction angle between the light beams and the object surface  170  according to the light spots will be described, and namely, step S 240  depicted in  FIG. 2  will be described.  FIG. 5  is a detailed flowchart of step S 240  depicted in  FIG. 2 . In the present exemplary embodiment, an arrangement composed of 5 light beams illustrated in  FIG. 6  will be described, where  FIG. 6  is a schematic diagram illustrating an arrangement of each of the light spots when the number of the light beams is 5. When the number of the light beams is equal to 5, an arrangement of a first light spot P 1  through a fourth light spot P 4  generated by the light beams presents an equilateral rhombus  610  on the same surface. A fifth light spot P 5  is arranged in the gravity center position of the equilateral rhombus  610 . A connection of the light spots P 2 , P 5  and P 4  may be considered as the first dimension (e.g. the X axis), while a connection of the light spots P 1 , P 5  and P 3  may be the second dimension (e.g. the Y axis).  FIG. 7  is a schematic diagram illustrating the object surface on the connection of the light spots P 2 , P 5  and P 4  to calculate the tilt angle when the number of the light beams is 5.  FIG. 7  is a schematic diagram illustrating the object surface on the connection of the light spots P 2 , P 5  and P 4  to calculate the tilt angle when the number of the light beams is 5, where the point AP is the focal point of the light beams. 
     Referring to  FIG. 5 ,  FIG. 6  and  FIG. 7  simultaneously, when the number of the light beams is 5, and step S 230  depicted in  FIG. 2  is finalized, all the light beams LB 1 ˜LB 5  are focused in the focal point AP, which represents that a position where the object surface  170  is located is actually a processing surface  710  ( FIG. 7 ). However, in the present exemplary embodiment, the tilt angle of the object surface  170  relative to the light beam emitting surface  115  is not calculated yet. Thus, in step S 510 , the computing device  140  adjusts the vertical distance Z by the object carrying device  150 . For example, the object surface  170  is uplifted for an adjustment value AZ of the vertical distance Z so that the object surface  170  reaches a predetermined measuring surface  720 . In an optimal situation where the light beam emitting surface  115  is parallel to the object surface  170 , the object surface  170  is supposed to reach the predetermined measuring surface  720 . The light beam emitting surface  115  is parallel to the predetermined measuring surface  720 . However, the object surface  170  may be actually uplifted to the measuring surface  730  due to error. 
     In step S 520  depicted in  FIG. 5 , the computing device  140  acquires a two-dimensional distribution of each of the light spots P 1 ˜P 5  by the image capture device  120 . In step S 530 , the computing device  140  measures a measured interval Λ between each of the light spots P 1 ˜P 5  according to the light spots P 1 ˜P 5  and the adjustment value ΔZ for uplifting the vertical distance Z and compares each of the measured intervals Λ with a predetermined interval α. In detail, when the number of the light beams is 5, the predetermined interval α represents an expected distance from one of the first light spot P 1  through the fourth light spot P 4  to the fifth light spot P 5 . The predetermined interval α may be decided through the predetermined adjustment value ΔZ and an incident angle θ set  of each of the light beams. In other words, the predetermined interval α may be obtained from the following formula (1): 
     
       
         
           
             
               
                 
                   
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                       ( 
                       
                         θ 
                         set 
                       
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                   = 
                   
                     
                       
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                           ⁢ 
                           
                               
                           
                           ⁢ 
                           Z 
                         
                       
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                         ⁡ 
                         
                           ( 
                           
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                             set 
                           
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     Therein, the predetermined interval α is a tangent function value of the adjustment value ΔZ of the vertical distance Z being multiplied by the incident angle of each of the light beams. 
     Each of the measured intervals Λ is an actually measured distance from one of the first P 1  through the fourth light spot P 4  to the fifth light spot P 5  obtained by the computing device  140  through the image IM. Referring to  FIG. 6  and  FIG. 7 , a measured interval Λ P45  is a measured distance from the fourth light spot P 4  to the fifth light spot P 5 , and a measured interval Λ P35  is a measured distance from the third light spot P 3  to the fifth light spot P 5 . 
     However, it is to be noticed that since the image capture device  120  captures the image IM from top to bottom in  FIG. 7 , by the obtained measured interval Λ P45 , only an actual distance from the light spot P 4  to the light beam LB 5  on a virtual  740  parallel to the predetermined measuring surface  720  may be measured. 
     Then in step S 540  of  FIG. 5 , the computing device  140  determines whether the measured interval Λ P45  is equal to the predetermined interval α. When the computing device  140  determines that the measured interval Λ P45  is equal to the predetermined interval α, it represents that the object surface  170  is located above the predetermined measuring surface  720 , and step S 570  is entered from step S 540 , and the computing device  140  does not need to calculate the correction angle of the light beams and determines that the light beam emitting surface  115  is parallel to the object surface  170 . 
     Otherwise, when the computing device  140  determines that that the measured interval Λ P45  is not equal to the predetermined interval α, it represents that the object surface  170  is not located above the predetermined measuring surface  720 , but uplifted to the actual measuring surface  730 . Thus, in the present exemplary embodiment, step S 550  is performed according the following algorithm, where the correction angle, such as a correction angle θ tilt   X  of the first dimension (the X axis) and a correction angle θ tilt   Y  of the second dimension (the Y axis), between the light beam emitting surface  115  and the object surface  170  is calculated according to the predetermined interval α, the incident angle θ set  of each of the light beams, the measured interval Λ P45  between the light spots P 4  and P 5  and the adjustment value ΔZ of the vertical distance Z. 
     When the number of the light beams is 5, and the incident angle θ set  of the light beam LB 4  projecting to the focal point AP is 45 degrees, as shown in  FIG. 6  and  FIG. 7 , a line segment K 1  vertical to the actual processing surface  710  has the same length as a line segment K 2  horizontal with the actual processing surface  710 . 
     The correction angle θ tilt   X  may be obtained by the following formulas (2) and (3): 
     
       
         
           
             
               
                 
                   
                     tan 
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                       ( 
                       
                         θ 
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                         X 
                       
                       ) 
                     
                   
                   = 
                   
                     
                       
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                         ⁢ 
                         
                             
                         
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                         1 
                       
                       
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                           45 
                         
                       
                     
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                               45 
                             
                           
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                             45 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
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                     θ 
                     tilt 
                     X 
                   
                   = 
                   
                     
                       
                         tan 
                         
                           - 
                           1 
                         
                       
                       ⁡ 
                       
                         ( 
                         
                           
                             K 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             1 
                           
                           
                             Λ 
                             
                               P 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               45 
                             
                           
                         
                         ) 
                       
                     
                     = 
                     
                       
                         
                           tan 
                           
                             - 
                             1 
                           
                         
                         ⁡ 
                         
                           ( 
                           
                             
                               K 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               1 
                             
                             
                               
                                 K 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 1 
                               
                               + 
                               α 
                             
                           
                           ) 
                         
                       
                       = 
                       
                         
                           tan 
                           
                             - 
                             1 
                           
                         
                         ⁡ 
                         
                           ( 
                           
                             
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   45 
                                 
                               
                               - 
                               α 
                             
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 45 
                               
                             
                           
                           ) 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     Namely, when the incident angle θ set  of the light beam LB 4  is 45 degrees, the correction angle θ tilt   X  of the first dimension (the X axis) is a arctangent function value of the measured interval Λ P45  minus the predetermined interval α being divided by the measured interval Λ P45 . The line segment K 2  is a value of the measured interval Λ P45  minus the predetermined interval α, i.e. K 2 =Λ P45 −α. A relationship formula between the predetermined interval α, the incident angle θ set  of the light beam and the adjustment value ΔZ of the vertical distance Z may be acquired by the formula (1) in the above. 
     The formula (3) may be rewritten as the following formula (4) according to the formula (1): 
     
       
         
           
             
               
                 
                   
                     θ 
                     tilt 
                     X 
                   
                   = 
                   
                     
                       
                         tan 
                         
                           - 
                           1 
                         
                       
                       ⁡ 
                       
                         ( 
                         
                           
                             Λ 
                             - 
                             α 
                           
                           Λ 
                         
                         ) 
                       
                     
                     = 
                     
                       
                         tan 
                         
                           - 
                           1 
                         
                       
                       ⁢ 
                       
                         { 
                         
                           
                             { 
                             
                               Λ 
                               - 
                               
                                 [ 
                                 
                                   
                                     tan 
                                     ⁡ 
                                     
                                       ( 
                                       
                                         θ 
                                         set 
                                       
                                       ) 
                                     
                                   
                                   × 
                                   Δ 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   Z 
                                 
                                 ] 
                               
                             
                             } 
                           
                           Λ 
                         
                         } 
                       
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
     That is, the correction angle θ tilt   X  of the first dimension is an arctangent function value of the measured interval Λ P45  minus the tangent function value of the incident angle θ set  of the light beam being multiplied by the adjustment value ΔZ of the vertical distance Z and then being divided by the measured interval Λ P45 . 
     Additionally, since in the present exemplary embodiment, each of the actual measured intervals between each of the light spots P 1 ˜P 5  may be obtained, the computing device  140  depicted in  FIG. 1  may calculate the correction angle θ tilt   X  of the first dimension (the X axis) according to the connection of the light spots P 2 , P 5  and P 4 , while the correction angle θ tilt   Y  of the second dimension (the Y axis) may be calculated according to the connection of the light spots P 1 , P 5  and P 3 . 
     In detail, the correction angle θ tilt   X  of the first dimension and the correction angle θ tilt   Y  of the second dimension is obtained by the following formulas (5) and (6): 
     
       
         
           
             
               
                 
                   
                     θ 
                     tilt 
                     X 
                   
                   = 
                   
                     
                       tan 
                       
                         - 
                         1 
                       
                     
                     ⁢ 
                     
                       { 
                       
                         
                           { 
                           
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 45 
                               
                             
                             - 
                             
                               [ 
                               
                                 
                                   tan 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                                 × 
                                 Δ 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 z 
                               
                               ] 
                             
                           
                           } 
                         
                         
                           Λ 
                           
                             P 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             45 
                           
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
             
               
                 
                   
                     θ 
                     tilt 
                     Y 
                   
                   = 
                   
                     
                       tan 
                       
                         - 
                         1 
                       
                     
                     ⁢ 
                     
                       { 
                       
                         
                           { 
                           
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 35 
                               
                             
                             - 
                             
                               [ 
                               
                                 
                                   tan 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                                 × 
                                 Δ 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 z 
                               
                               ] 
                             
                           
                           } 
                         
                         
                           Λ 
                           
                             P 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             35 
                           
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
     In the exemplary embodiment described in the above, the incident angle θ set  of the light beam LB 4  is set as 45 degrees. However, if the incident angle θ set  of the light beam LB 4  projecting to the focal point AP is not predetermined 45 degrees, the vertical line segment K 1  illustrated in  FIG. 7  is calculated by the following formula (7): 
     
       
         
           
             
               
                 
                   
                     cot 
                     ⁡ 
                     
                       ( 
                       
                         θ 
                         set 
                       
                       ) 
                     
                   
                   = 
                   
                     
                       
                         K 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         1 
                       
                       
                         K 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         2 
                       
                     
                     = 
                     
                       
                         
                           
                             K 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             1 
                           
                           
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 45 
                               
                             
                             - 
                             α 
                           
                         
                         ⇒ 
                         
                           K 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           1 
                         
                       
                       = 
                       
                         
                           ( 
                           
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 45 
                               
                             
                             - 
                             α 
                           
                           ) 
                         
                         × 
                         
                           cot 
                           ⁡ 
                           
                             ( 
                             
                               θ 
                               set 
                             
                             ) 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
           
         
       
     
     The formula (3) for calculating the correction angle θ tilt   X  of the first dimension is rewritten as the following formula (8) according to the formulas (1) and (7): 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           θ 
                           tilt 
                           X 
                         
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁡ 
                           
                             ( 
                             
                               
                                 K 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 1 
                               
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   45 
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁡ 
                           
                             ( 
                             
                               
                                 
                                   ( 
                                   
                                     
                                       Λ 
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         45 
                                       
                                     
                                     - 
                                     α 
                                   
                                   ) 
                                 
                                 × 
                                 
                                   cot 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                               
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   45 
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁡ 
                           
                             ( 
                             
                               
                                 
                                   { 
                                   
                                     
                                       Λ 
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         45 
                                       
                                     
                                     - 
                                     
                                       [ 
                                       
                                         
                                           tan 
                                           ⁡ 
                                           
                                             ( 
                                             
                                               θ 
                                               set 
                                             
                                             ) 
                                           
                                         
                                         × 
                                         Δ 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         z 
                                       
                                       ] 
                                     
                                   
                                   } 
                                 
                                 × 
                                 
                                   cot 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                               
                               
                                 Λ 
                                 
                                   
                                     P 
                                     ⁢ 
                                     
                                         
                                     
                                     ⁢ 
                                     45 
                                   
                                   ⁢ 
                                   
                                       
                                   
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   8 
                   ) 
                 
               
             
           
         
       
     
     The correction angle θ tilt   Y  of the second dimension may be obtained by the following formula (9): 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           θ 
                           tilt 
                           Y 
                         
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁡ 
                           
                             ( 
                             
                               
                                 K 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 1 
                               
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   35 
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁡ 
                           
                             ( 
                             
                               
                                 
                                   ( 
                                   
                                     
                                       Λ 
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         35 
                                       
                                     
                                     - 
                                     α 
                                   
                                   ) 
                                 
                                 × 
                                 
                                   cot 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                               
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   35 
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁡ 
                           
                             ( 
                             
                               
                                 
                                   { 
                                   
                                     
                                       Λ 
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         35 
                                       
                                     
                                     - 
                                     
                                       [ 
                                       
                                         
                                           tan 
                                           ⁡ 
                                           
                                             ( 
                                             
                                               θ 
                                               set 
                                             
                                             ) 
                                           
                                         
                                         × 
                                         Δ 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         z 
                                       
                                       ] 
                                     
                                   
                                   } 
                                 
                                 × 
                                 
                                   cot 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                               
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   35 
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   9 
                   ) 
                 
               
             
           
         
       
     
     Namely, the correction angle θ tilt   X  of the first dimension is an arctangent function value of the measured interval Λ P45  minus the tangent function value of the incident angle θ set  of the light beam of the first dimension being multiplied by the adjustment value ΔZ of the vertical distance Z, then being multiplied by the cotangent function value of the incident angle θ set  and being divided by the measured interval Λ P45 . If the incident angle θ set  is 45 degrees, the cotangent function value of the incident angle θ set  is 1 so as to conform to the formula (4). 
     In  FIG. 5 , step S 560  is entered after step S 550 , the computing device  140  depicted in  FIG. 1  may control the axial direction controller  130  according to the correction angles θ tilt   X  and θ tilt   Y  in the first and the second dimensions so as to correct and compensate the tilt angle of the light beam emitting surface  115  of the light source device  110 , and step S 570  is entered to determine that the corrected light beam emitting surface  115  is parallel to the object surface  170 . 
     The foregoing embodiment is implemented according to the condition where the number of the light beams is 5 and the algorithm formulas in step S 550 . Hereinafter, exemplary embodiments implemented according to the conditions where the number of the light beams is respectively 4 and 3 will be described.  FIG. 8  is a schematic diagram illustrating an arrangement of each of the light spots when the number of the light beams is 4.  FIG. 9  is a schematic diagram illustrating the object surface on a connection of light spots P 1  and P 2  to calculate the tilt angle when the number of the light beams is 4.  FIG. 9  is a schematic diagram illustrating the object surface on the connection of light spots P 1  and P 2  to calculate the tilt angle when the number of the light beams is 4. The triangle shape and the arrangement of the light spots illustrated in  FIG. 8  are similar to  FIGS. 4A and 4B , which will not be repeated hereinafter. 
       FIG. 9  is similar to  FIG. 7 , and the difference therebetween lies in that  FIG. 9  illustrates a connection between the light spots P 1 ˜P 2  depicted in  FIG. 8 . Here, the predetermined interval α of the present exemplary embodiment is a half of each expected side length (e.g. a side length between the light spots P 1 ˜P 2 ) in the equilateral triangle  410  depicted in  FIG. 8 . The measured interval Λ is a half of a measured side length between two light spots among the first light spot P 1  through the third light spot P 3 . For example, the measured interval Λ P14  is a half of the measured side length between the light spots P 1 ˜P 2 . Only an actual distance from the light spot P 2  to a central line segment on a virtual surface parallel to the predetermined measuring surface  920  may measured according to the obtained measured interval Λ P12 . Each corner of the equilateral triangle  410  has a predetermined angle β. 
     Thus, referring to both  FIG. 8  and  FIG. 9 , the predetermined interval α may be acquired by formula (10): 
     
       
         
           
             
               
                 
                   
                     tan 
                     ⁡ 
                     
                       ( 
                       
                         θ 
                         set 
                       
                       ) 
                     
                   
                   = 
                   
                     
                       
                         α 
                         
                           Δ 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           Z 
                         
                       
                       ⇒ 
                       α 
                     
                     = 
                     
                       
                         tan 
                         ⁡ 
                         
                           ( 
                           
                             θ 
                             set 
                           
                           ) 
                         
                       
                       × 
                       Δ 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       Z 
                     
                   
                 
               
               
                 
                   ( 
                   10 
                   ) 
                 
               
             
           
         
       
     
     The measured interval Λ P14  may be obtained according to a distance L P24  between the light spots P 2  and P 4  and the predetermined angle β of the triangle formed by the light spots P 1 ˜P 3 , as shown in the following formula (11):
 
Λ P14   =L   P24 ×cos(β/2)  (11)
 
     Namely, the measured interval Λ P14  is a value obtained by multiplying the distance between the second light spot P 2  and the fourth light spot P 4  on the surface formed by the connection of the light spots P 1 ˜P 2  by a cosine function value of a half of the predetermined angle β. 
     The correction angle θ tilt  on a connection of the first light spot P 1  through the second light spot P 2  may be acquired by calculating an adjusted formula (12) according to the formula (8): 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           θ 
                           tilt 
                         
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁢ 
                           
                             { 
                             
                               
                                 
                                   { 
                                   
                                     
                                       Λ 
                                       
                                         P 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         14 
                                       
                                     
                                     - 
                                     
                                       [ 
                                       
                                         
                                           tan 
                                           ⁡ 
                                           
                                             ( 
                                             
                                               θ 
                                               set 
                                             
                                             ) 
                                           
                                         
                                         × 
                                         Δ 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         Z 
                                       
                                       ] 
                                     
                                   
                                   } 
                                 
                                 × 
                                 
                                   cot 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                               
                               
                                 Λ 
                                 
                                   P 
                                   ⁢ 
                                   
                                       
                                   
                                   ⁢ 
                                   14 
                                 
                               
                             
                             } 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         ⁢ 
                         
                           
                             tan 
                             
                               - 
                               1 
                             
                           
                           ⁢ 
                           
                             { 
                             
                               
                                 
                                   { 
                                   
                                     
                                       
                                         L 
                                         
                                           P 
                                           ⁢ 
                                           
                                               
                                           
                                           ⁢ 
                                           24 
                                         
                                       
                                       × 
                                       
                                         cos 
                                         ⁡ 
                                         
                                           ( 
                                           
                                             β 
                                             / 
                                             2 
                                           
                                           ) 
                                         
                                       
                                     
                                     - 
                                     
                                       [ 
                                       
                                         
                                           tan 
                                           ⁡ 
                                           
                                             ( 
                                             
                                               θ 
                                               set 
                                             
                                             ) 
                                           
                                         
                                         × 
                                         Δ 
                                         ⁢ 
                                         
                                             
                                         
                                         ⁢ 
                                         Z 
                                       
                                       ] 
                                     
                                   
                                   } 
                                 
                                 × 
                                 
                                   cot 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                               
                               
                                 
                                   L 
                                   
                                     P 
                                     ⁢ 
                                     
                                         
                                     
                                     ⁢ 
                                     24 
                                   
                                 
                                 × 
                                 
                                   cos 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       β 
                                       / 
                                       2 
                                     
                                     ) 
                                   
                                 
                               
                             
                             } 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   12 
                   ) 
                 
               
             
           
         
       
     
     Therein, θ tilt  is the correction angle on the connection of the first light spot P 1  through the second light spot P 2 , L P24  is the distance between the second light spot P 2  and the fourth light spot P 4 , β is the predetermined angle of each corner of the equilateral triangle  410 , θ set  is the incident angle of each of the light beams LB 1  and LB 2  respectively corresponding to the first light spot P 1  and the second light spot P 2 , and ΔZ is the adjustment value of the vertical distance Z. In other words, the correction angle θ tilt  located on the connection of the first light spot P 1  through the second light spot P 2  is an arctangent function value of the measured interval Λ P14  minus the tangent function value of the incident angle θ set  of each of the light beams LB 1  and LB 2  corresponding to the first light spot P 1  and the second light spot P 2 , which is multiplied by the adjustment value ΔZ of the vertical distance Z and then multiplied by the cotangent function value of the incident angle θ set , and divided by the measured interval Λ P14 . If the incident angle θ set  of each of the light beam is set as 45 degrees, the cotangent function value of the incident angle θ set  is 1. 
       FIG. 10  is a schematic diagram illustrating an arrangement of each of the light spots when the number of the light beams is 3. When the number of the light beams is 3, an arrangement of the three light spots P 1 ˜P 3  generated by light beams presents a vertical isosceles triangle  1000  on the same surface. The first light spot P 1  and the second light spot P 2  are two are respectively located at two acute vertices of the vertical isosceles triangle, and the third light spot P 3  is located at the endpoint of the vertical isosceles triangle  1000 . 
     Here, the predetermined interval α of the present exemplary embodiment is an expected distance between one of the first light spot P 1  through the second light spot P 2  to the third light spot P 3 . Each measured interval Λ is a measured distance from one of the first light spot P 1  and the second light spot P 2  to the third light spot P 3 . For example, the measured interval Λ P13  is the measured distance between the light spots P 1  and P 3 . 
     Accordingly, a connection between the first light spot P 1  and the third light spot P 3  may be considered as the first dimension (the X axis), and the connection between the second light spot P 2  and the third light spot P 3  may be considered as the second dimension (the Y axis). Thus, the correction angle θ tilt   X  of the first dimension and the correction angle θ tilt   Y  of the second dimension are respectively obtained by the following formulas (13) and (14): 
     
       
         
           
             
               
                 
                   
                     θ 
                     tilt 
                     X 
                   
                   = 
                   
                     
                       tan 
                       
                         - 
                         1 
                       
                     
                     ⁢ 
                     
                       { 
                       
                         
                           { 
                           
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 13 
                               
                             
                             - 
                             
                               [ 
                               
                                 
                                   tan 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                                 × 
                                 Δ 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 z 
                               
                               ] 
                             
                           
                           } 
                         
                         
                           Λ 
                           
                             P 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             13 
                           
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   ( 
                   13 
                   ) 
                 
               
             
             
               
                 
                   
                     θ 
                     tilt 
                     Y 
                   
                   = 
                   
                     
                       tan 
                       
                         - 
                         1 
                       
                     
                     ⁢ 
                     
                       { 
                       
                         
                           { 
                           
                             
                               Λ 
                               
                                 P 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 23 
                               
                             
                             - 
                             
                               [ 
                               
                                 
                                   tan 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       θ 
                                       set 
                                     
                                     ) 
                                   
                                 
                                 × 
                                 Δ 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 z 
                               
                               ] 
                             
                           
                           } 
                         
                         
                           Λ 
                           
                             P 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             23 
                           
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   ( 
                   14 
                   ) 
                 
               
             
           
         
       
     
     Namely, the correction angle θ tilt   X  located on the connection between the first light spot P 1  through the third light spot P 3  is an arctangent function value of the measured interval Λ P13  minus the tangent function value of the incident angle of the light beam corresponding to the first light spot P 1 , which is multiplied by the adjustment value ΔZ of the vertical distance Z, and divided by the measured interval Λ P13 . Other detailed of the present exemplary embodiment may refer to the foregoing exemplary embodiments, and will not be repeated hereinafter. 
     In the present exemplary embodiment, the detecting system  100  depicted in  FIG. 1  may be installed in a processing apparatus. Thus, the detecting system  100  may further include a processing equipment. The processing equipment is coupled to the computing device  140 , such that the computing device  140  calculates the correction angle according to the light spots to correct the relative positional relationship between the processing equipment and the object surface  170  so as to mitigate errors that might occur in processing procedures. In the present exemplary embodiment, the computing device  140  of the detecting system  100  may not only calculate the correction angle between the light source device and the object surface but also adjust the correction angle and the vertical distance between the light source device  110  and the object surface  170  by the axial direction controller  130  and the object carrying device  150  so as to finalize the procedure of compensating the tilt angle. 
     Based on the above, in the method and system of detecting the tilt angle and the method and the system of compensating the same according to the exemplary embodiments of the disclosure, the positional relationship among a plurality of light spots on the object surface is obtained by utilizing the light source device and the image sensing device which are coaxially disposed, and spatial relationships (such a distance and a tilt angle) between the laser light source (or the processing equipment) and the object surface is adjusted through algorithm calculations, such that the detection device is not limited to the material composition of the object, the reflectivity and flatness of the object surface and capable of simultaneously measuring the tilt angles of two dimensions on the object surface. In addition, in the compensation method and system introduced by the exemplary embodiments of the disclosure, a processing equipment may be further installed, and the relative spatial relationship between the processing equipment and the object surface is adjusted according to the tilt angle obtained through the calculations. Accordingly, an effect and quality of processing the object may be enhanced so as to facilitate in industrial equipments which perform laser processing procedures. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.