TW201616092A - Method for measuring three-dimensional shape of object - Google Patents

Abstract

The present invention relates to a method for measuring a three-dimensional shape of object comprising steps: disposing two linear image capturing units on a moving path of an object under test to perform scanning in order to capture an image of the object while the object moves at high speed. With the parameters computation, such as specifications of the linear image capturing unit, an image moving distance, an angle between a scanning direction of the linear image capturing unit and a normal direction of a platform where the object is located, etc., the three-dimensional coordinates of the object can be precisely captured to further establish its three-dimensional shape .

Description

Method for measuring the three-dimensional shape of an object 【0001】

The invention relates to a method for measuring the three-dimensional shape of an object, in particular to a method for measuring the three-dimensional shape of an object having the advantages of high speed and high resolution.

【0002】

Among various automatic detection technologies, optical measurement method combined with high-resolution image capture system not only measures fast speed, high precision, but also does not need to be in direct contact with the object to be tested, so it is concerned with speed and non-contact objects. Under the limited conditions, the optical measurement method is the best choice.

[0003]

There are quite a few optical measurement methods, such as laser focusing technology, line laser scanning method, structured light, projection stripe method, embossing method and interferometer, etc., which can be used to detect the three-dimensional contour of an object; Due to the pixel number and image capturing principle of the surface image capturing device, the resolution and measurement speed of the prior art cannot be too high, and can not be applied to the process line detection, but can only be applied to offline detection.

[0004]

The Republic of China Patent Publication No. I229186 discloses a two-view three-dimensional topographic image linear scanning detecting device comprising a positive viewing angle linear scanning device, a oblique viewing angle linear scanning device and a light source device. The height distribution of the surface defects of the object to be tested can be estimated by the cross-sectional image of the positive viewing angle sensed by the linear viewing device of the positive viewing angle plus the oblique cross-sectional image of the object to be measured sensed by the oblique-angle linear scanning device. .

[0005]

In the scanning detection device of the present case, the object is scanned using a double angle of view of the positive-angle linear scanning device and the oblique-angle linear scanning device, which is performed by conventional stereoscopic vision, when light rays of different directions are projected on the surface of the object. The dark or shiny state produced determines whether the surface defect of the object to be measured is convex or concave, and then estimates the surface contour of the object by using the distribution of the dark portion and the bright portion. In addition, it represents a cross-sectional cross section of the object to be measured obtained by sensing, and an appropriate cross-over operation to estimate the image of the three-dimensional shape, thereby deriving the object to be measured. The approximate volume, approximate cross-sectional shape and height of the surface foreign object.

[0006]

However, it has been examined that the three-dimensional topographic image detecting device disclosed in the above patent document does not have the characteristics of high resolution, and it is more difficult to determine how to obtain the parameter of the object in height, and thus is not sufficient for application line detection. The technical field still needs further development to meet research units and related industries that have high demand for detection speed and resolution.

【0007】

The main object of the present invention is to provide a method for measuring the three-dimensional shape of an object, which can scan the object under high-speed movement and obtain the coordinate parameter of the height of the object, thereby obtaining the three-dimensional shape of the object. .

[0008]

Another object of the present invention is to provide a method for measuring the three-dimensional shape of an object, which can detect the presence or absence of flaws and defects in the appearance of the three-dimensional shape obtained above, and can be combined with the conveying system of the production line to achieve high speed. The goal of high resolution.

【0009】

Still another object of the present invention is to provide a method for measuring a three-dimensional shape of an object, which is applicable to detecting various types of modeling elements, photovoltaic elements, microelectromechanical elements, and semiconductor package components.

[0010]

In order to achieve the above object, the present invention discloses a method for measuring a three-dimensional shape of an object, which is used for measuring a three-dimensional shape of an object, comprising: setting the object on a platform, and the object is along a moving path. Moving the object by using a first image capturing unit and a second image capturing unit, the first image capturing unit and the second image capturing unit are disposed above the moving path, and scanning The direction and the normal direction of the platform respectively have a first angle and a second angle, and the horizontal plane of the intersection of the image capturing axes of the first image capturing unit and the second image capturing unit is a reference plane Calculating a plurality of three-dimensional coordinate parameters of the surface of the object, the three-dimensional coordinate parameters are: , , Where n _p is the nth pixel position of the first image capturing unit, P _{p is} the pixel pitch of the first image capturing unit, m is the image magnification, θ _{1 is} the first angle, θ ₂ For the second angle, N ₁ P and N ₂ P are the distances that the images are moved when the object is captured by the first image capturing unit and the second image capturing unit, respectively. And determining, by the first image capturing unit and the second image capturing unit, a height difference between the reference image and the reference surface; and establishing a three-dimensional shape of the object according to the three-dimensional coordinate parameters.

10‧‧‧ platform

21‧‧‧First image capture unit

22‧‧‧Second image capture unit

30‧‧‧ objects

30A‧‧‧ objects

W‧‧‧Moving path

θ ₁ ‧‧‧first angle

θ ₂ ‧‧‧second angle

H‧‧‧height

N ₁ ‧‧‧Px coordinates

N ₂ ‧‧‧Px coordinates

R‧‧‧ intersection line

[0011]

FIG. 1 is a schematic structural view of a preferred embodiment of the present invention, in which the first image capturing unit and the second image capturing unit are disposed obliquely to scan an object on the platform;
FIG. 2 is a schematic structural view of another preferred embodiment of the present invention, in which one of the first image capturing unit and the second image capturing unit is vertically disposed on the scanning platform. FIG. 3A and FIG. 3B are schematic diagrams showing the structure of another preferred embodiment of the present invention in operation, for indicating that only the first image capturing unit is used for scanning.

[0012]

For a better understanding and understanding of the features and advantages of the present invention, the preferred embodiments and the detailed description are described as follows:

[0013]

Referring to FIG. 1 , in order to implement the method for measuring the three-dimensional shape of the object disclosed in the present invention, the hardware structure used includes a platform 10 , a first image capturing unit 21 and a second image. The unit 22 is captured. The platform 10 is used to carry the object 30 to be tested, and in the form of practical application, the platform 10 can be a conveyor belt that is driven by a motor to travel in a fixed direction, and the object 30 carried by the platform 30 is also Therefore, traveling in the fixed direction allows the object 30 itself to be defined as moving along a moving path W (the object 30A is exemplified by the position at which the object 30 passes over the moving path W). The first image capturing unit 21 and the second image capturing unit 22 are disposed above the moving path W to scan the object 30.

[0014]

The first image capturing unit 21 and the second image capturing unit 22 used in the present invention are linear image capturing devices, which comprise a charge-coupled device (CCD) or a complementary metal oxide. a photosensitive element such as a semiconductor (Complementary Metal-Oxide-Semiconductor, CMOS), and arranging the photosensitive elements in a straight line (this straight line is perpendicular to the moving path described above), has a high linear density, and thus has extremely high pixels. Provides super high resolution.

[0015]

The operating mechanism of the present invention utilizes two sets of line image capturing units to accumulate a superimposed image of each group of line pixels obtained by the line image capturing unit when the object to be measured is displaced, and then in two The three-dimensional contour of the surface of the object to be tested can be quantitatively determined by finding the scanning movement position corresponding to the specific point in the group superimposed image.

[0016]

Please refer to FIG. 2 , which is a simplified arrangement of the preferred embodiment shown in FIG. 1 , and the difference is that the first image capturing unit 21 and the second image capturing unit 22 shown in FIG. 1 The scanning direction and the normal direction of the platform 10 respectively have a first angle θ ₁ and a second angle θ ₂ , and the second image is to set the first image capturing unit 21 to the vertical direction of the object 30, The image capturing unit 22 maintains the oblique image capturing, and the image capturing axes of the two (that is, the extension lines of the scanning direction) have an intersecting line R, and the horizontal plane where the intersecting lines are located is the reference plane. When the platform 10 is not moved, the axial intersection of the first pixel of the first image capturing unit 21 is the coordinate origin, the line pixel direction is the Y axis, and the moving direction of the platform 10 is the X axis (the opposite direction of the movement) If it is positive, then the specific point coordinates (x, y) of the object 30 to be tested and its height h(x, y) relative to the reference plane are:
x = N1P
y =
h(x, y) =
Where n _p is the nth pixel position of the first image capturing unit 21, P _p is the pixel pitch of the first image capturing unit 21, m is the image magnification, and h is the object at the scanned position and the reference The height difference between the faces, N ₁ P and N ₂ P are the distances at which the images are moved by the first image capturing unit 21 and the second image capturing unit 22, respectively, where the images are moved, where N ₁ P is equivalent to the horizontal distance between the original position of the image and the position after the movement, that is, the coordinate on the x-axis. Among them, P is a line image capturing device (the first image capturing unit 21 and the second image capturing unit 22) for scanning the image capturing interval, for example, moving 1 micrometer to take an image, or moving 2 micrometers. Taking an image or the like; N ₁ and N ₂ are respectively indicating that the first image capturing unit 21 and the second image capturing unit 22 see the same point when moving to the N ₁ and N ₂ image positions respectively. That is, the first image capturing unit 21 and the second image capturing unit 22 scan the image of the point when scanning the image. For example, for a point on the reference plane, the two image capturing units scan the point at the same time to obtain the image, so at this time N ₁ =N ₂ , the height is regarded as zero; and for the point with height, N ₁ , N ₂ The values of the two will be different.

[0017]

As shown in FIG. 1 , the first image capturing unit 21 and the second image capturing unit 22 are both obliquely imaged, and the intersection of the image capturing axes on the platform 10 is the coordinate origin. At this time, the specific point coordinates (x, y) of the object 30 to be measured and its height h(x, y) with respect to the reference plane are corrected as:
x =
y =
h(x, y) =

[0018]

It can be seen from the above formula that if the present invention is to achieve high resolution, the key is the image spacing P of the first image capturing unit 21 and the second image capturing unit 22 when scanning the object 30. When the P value is small, The resolution which can be provided by the invention can be higher, so that the measurement resolution of the micrometer level can be easily achieved, in particular, the invention can measure the height of the object, not the planar two-dimensional measurement, the amount The measurement level is a major breakthrough in the technical field, and can be used to achieve subtle height differences. In addition, if N ₁ and N _{2 are} set with the sub-pixel technique, the measurement resolution can be improved to achieve sub-micron measurement accuracy. The measuring speed of the present invention depends on the moving speed of the platform 10, so that a high-speed, high-precision measuring target can be achieved by selecting a high-speed moving platform.

[0019]

The two sets of line image capturing units provided by the present invention can also be integrated in another preferred embodiment to use a line type image sensing device comprising two image capturing units to provide two lenses in the object to be tested. Above the moving path, the object is scanned and imaged by different angles, and the horizontal plane where the intersection lines of the image axes before and after the image are located is the reference plane. In addition, the two sets of line image capturing units can be integrated into a single lens, and the image is scanned at different angles of the object in the manner of moving forward and backward. At this time, the movement is not limited to the platform for carrying the object, and Moving the aforementioned single lens under the condition that the platform is stationary, there is a relative movement between the lens and the object. Please refer to FIGS. 3A and 3B , which is to scan the object 30 only by using the first image capturing unit 21 , and when the object 30 is moved and the relative position of the first image capturing unit 21 is changed, the first image 撷The scanning direction of the taking unit 21 and the normal direction of the platform respectively have a first angle θ ₁ and a second angle θ ₂ , and the three-dimensional shape of the object 30 can be established by the above formula.

[0020]

To measure the different size and resolution requirements, you can adjust the image spacing P when scanning the image to suit the objects of various sizes, and establish the three-dimensional shape of the object under test, or Find out related derivatives such as 瑕疵.

[0021]

In the preferred embodiment of the present invention for establishing a three-dimensional topography of an object, the method of the present invention can be organized into the following steps:
Step S1: setting the object on a platform, and moving the object along a moving path;
Step S2: scanning the object by using a first image capturing unit and a second image capturing unit, wherein the first image capturing unit and the second image capturing unit are disposed above the moving path, and scanning the same The direction and the normal direction of the platform respectively have a first angle and a second angle, and the horizontal plane of the intersection of the image capturing axes of the first image capturing unit and the second image capturing unit is a reference plane ;
Step S3: calculating a plurality of three-dimensional coordinate parameters of the surface of the object, the three-dimensional coordinate parameters are: , , Where n _p is the nth pixel position of the first image capturing unit, P _{p is} the pixel pitch of the first image capturing unit, m is the image magnification, θ _{1 is} the first angle, θ ₂ For the second angle, N ₁ P and N ₂ P are the distances that the images are moved when the object is captured by the first image capturing unit and the second image capturing unit, respectively. a height difference between the object scanned by the first image capturing unit and the second image capturing unit and the reference surface; and step S4: establishing a three-dimensional topography of the object according to the three-dimensional coordinate parameters.

[0022]

In summary, the present invention discloses in detail a method for measuring the three-dimensional shape of an object, which is based on the on-line measurement of the process, and considers that the object is measured under high-speed movement. Therefore, under the demand of high speed and high resolution, the high pixel line image capturing unit with high transmission rate is the core of the architecture, and the optical image capturing system is designed and fixed on the detecting machine according to the size of the object to be tested. On the top, the image is scanned by moving objects. In addition, the present invention can also easily change the resolution to set the pitch of hundreds of micrometers to submicrometers for different types of objects; and also increase the number of probes of the image capturing unit and the graphics of the computing end depending on the width of the object. The number of processors, combined with the technology of parallel processing, meets the demand.

[0023]

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the variations, modifications, and modifications of the shapes, structures, features, and spirits described in the claims of the present invention. All should be included in the scope of the patent application of the present invention.

10‧‧‧ platform

21‧‧‧First image capture unit

22‧‧‧Second image capture unit

30‧‧‧ objects

30A‧‧‧ objects

W‧‧‧Moving path

θ ₁ ‧‧‧first angle

θ ₂ ‧‧‧second angle

H‧‧‧height

N ₁ P‧‧‧x coordinates

N ₂ P‧‧‧x coordinates

R‧‧‧ intersection line

Claims (5)

[Item 1] A method for measuring a three-dimensional shape of an object for measuring a three-dimensional shape of an object, comprising:
Setting the object on a platform, and moving the object along a moving path;
The first image capturing unit and the second image capturing unit are configured to scan the object, and the first image capturing unit and the second image capturing unit are disposed above the moving path, and the scanning direction thereof is The normal direction of the platform has a first angle and a second angle, and the horizontal plane of the intersection of the image capturing axes of the first image capturing unit and the second image capturing unit is a reference plane;
Calculating a plurality of three-dimensional coordinate parameters of the surface of the object, the three-dimensional coordinate parameters are: , , ), The n-th pixel position where _np is the first image capturing unit, the pixel P _p for the pitch of the first image capturing unit, m is the image magnification, θ ₁ is the first angle, θ ₂ is The second angle, N ₁ P and N ₂ P are the distances that the images are moved when the object is captured by the first image capturing unit and the second image capturing unit, h is The height difference between the object and the reference surface scanned by the first image capturing unit and the second image capturing unit; and establishing a three-dimensional topography of the object according to the three-dimensional coordinate parameters. [Item 2] The method for measuring a three-dimensional shape of an object according to the first aspect of the invention, wherein the first image capturing unit and the second image capturing unit respectively comprise at least one set of linear photosensitive elements. [Item 3] The method for measuring a three-dimensional shape of an object according to claim 1, wherein the first image capturing unit and the second image capturing unit respectively comprise a charge coupled device or a complementary metal oxide semiconductor Wait for the photosensitive element. [Item 4] The method for measuring a three-dimensional shape of an object according to the first aspect of the invention, wherein the first image capturing unit and the second image capturing unit scan the object, the first image capturing The unit and the second image capturing unit simultaneously scan the object. [Item 5] A method for measuring a three-dimensional shape of an object for measuring a three-dimensional shape of an object, comprising:
Setting the object on a platform, and moving the object along a moving path;
Scanning the object by using a first image capturing unit, the first image capturing unit is disposed above the moving path, and the scanning direction has a first angle and a second angle with a normal direction of the platform, and The horizontal plane of the intersection line of the image capturing axes of the first image capturing unit and the second image capturing unit is a reference surface;
The first image capturing unit is used to scan the object again, and the object system moves along the moving path to another position. At this time, the scanning direction of the first image capturing unit and the normal direction of the platform have a second Angle
Calculating a plurality of three-dimensional coordinate parameters of the surface of the object, the three-dimensional coordinate parameters are: , , Where n _p is the nth pixel position of the first image capturing unit, P _{p is} the pixel pitch of the first image capturing unit, m is the image magnification, θ _{1 is} the first angle, θ ₂ For the second angle, N ₁ P and N ₂ P are the distances that the images are moved when the object is captured by the first image capturing unit and the second image capturing unit, respectively. And determining, by the first image capturing unit and the second image capturing unit, a height difference between the reference image and the reference surface; and establishing a three-dimensional shape of the object according to the three-dimensional coordinate parameters.