TWI460395B - Flatness measurement device and measuring method thereof - Google Patents

Description

Flatness detecting device and detecting method thereof

The present invention relates to a flatness detecting device and a detecting method thereof, and more particularly to a detecting device for determining the surface flatness of a workpiece to be tested by an optical image signal and a detecting method thereof.

In the traditional flatness detection method, the platform and the gap ruler are mostly used for manual detection. The flatness detection method is as follows: firstly, the object to be tested is placed on a verified reference platform, and then the operator uses a gap gauge of a standard specification to insert a gap between the object to be tested and the platform to check whether the flatness is qualified. . However, in this way, the flatness of the test object is detected, and the minimum unit limited by the gap ruler is 0.1 mm (100 μm), so the accuracy is generally only 0.1 mm, and the detection process needs to be judged by the operator, so There will be problems with standard inconsistencies. In addition, this method is a contact type detection method, that is, the surface of the object to be tested needs to be in contact with the gap ruler during the detection, and collision and friction are inevitable during the detection process. In this way, the detection accuracy of the platform and the gap gauge will inevitably decrease after a long period of use, and the surface of the object to be tested may be scratched, thereby affecting the surface quality.

The invention relates to a flatness detecting device and a detecting method thereof, which are used as a reference for flatness detection by means of gap light transmission image processing, and numerical analysis is used to calculate between the lower edge of the object to be tested and the bearing plane The gap height is used to determine whether the flatness is acceptable.

According to an aspect of the present invention, a flatness detecting device includes a carrying platform, a lighting module, a light receiving module, an image processing module, and a matching module. The carrying platform has a plane for carrying a test object and for a light to penetrate. The light emitting module is disposed in the carrying platform to emit the light. The light is emitted by the object to be tested near the side of the plane and the plane to generate a detection light. The light receiving module is located on one side of the carrying platform for receiving the detecting light and generating an image signal. The image processing module is configured to receive and process the image signal to measure a gap height between the side of the object to be tested and the plane. The comparison module outputs a detection signal according to the ratio of the gap height to a standard value to determine whether the gap height meets the standard.

According to another aspect of the present invention, a flatness detecting method is provided, comprising the following steps. A test object is placed on a plane of a carrying platform. A detection light is generated by emitting a light from the side of the object close to the plane and the plane. Performing an image processing on the detection light to measure a gap height between the side of the object to be measured close to the plane and the plane. According to the ratio of the gap height to a standard value, a detection signal is generated to determine whether the gap height meets the standard.

In order to provide a better understanding of the above and other aspects of the present invention, the following detailed description of the embodiments and the accompanying drawings

The flatness detecting device and the detecting method thereof of the embodiment are to place the object to be tested on the carrying platform, and the light emitting module has a light emitting module projecting light toward the object to be tested, and the light passes through the narrow between the object to be tested and the carrying platform. Through the seam And receiving the image signal by the light receiving module, and the image signal is processed by the image processing module, and can be used to calculate the gap height between the lower edge (side) of the object to be tested and the bearing plane, and the gap height Compare with a standard value. If the comparison result shows that the gap height is greater than the standard value, it is judged to be unqualified. If the gap height is less than the standard value, it is judged as qualified, as the basis for the flatness detection. The detecting device of the embodiment adopts non-contact measuring, does not scratch the object to be tested, and is a quasi-standardized automatic detecting process and automatically judges whether the standard is met according to the comparison result, thereby improving the precision (up to 0.01 mm or less) ), efficiency (detection time is less than 1.5 seconds / piece) and accuracy, to save manpower and cost, and to avoid the problem of standard inconsistency caused by human factors.

The following is a detailed description of various embodiments, which are intended to be illustrative only and not to limit the scope of the invention.

First embodiment

1 and 2, wherein FIG. 1 is a block diagram showing a flatness detecting device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the internal portion of a carrying platform in an embodiment. In the first embodiment, the flatness detecting device 100 includes a carrying platform 110, a lighting module 120, a light receiving module 130, an image processing module 140, and a matching module 150. The carrying platform 110 has a plane 112 for carrying a test object 10 and for penetrating a light L. This plane 112 includes a light transmissive portion, such as a hollow portion, clear glass or acryl, which serves as a reference surface for flatness detection. The carrier platform 110 is a hollow body under the plane 112 for placing the light emitting module 120, such as an array of light emitting diodes or other light emitting elements 122. As shown in FIG. 2, for example, a plurality of LEDs connected in series are used as the light-emitting elements 122, surrounding the interior of the carrier platform 110, and emitting light directly toward the plane 112 of the carrier platform 110, or emitting light toward the sidewalls 114. The light is directed to the plane 112 by reflection so that the light is evenly diverged in all directions. In addition, the illuminating module 120 uniformly diverging around can avoid the glare/stray interference and affect the quality of the detection, and can simultaneously perform the flatness detection in each detection direction A~F to improve the efficiency.

In the first and second figures, the light L is advanced toward the plane 112, for example, by direct or reflective, and passes through the plane 112 to reach the lower edge 12 of the object to be tested 10. It should be noted that the lower edge 12 refers to the side of the object 10 to be close to the plane 112, which is located below, so the directionality is defined as the "lower edge", and does not refer to the specific side. At this time, a part of the light is emitted through a slit between the lower edge 12 of the object to be tested 10 and the plane 112 to generate a detection light T. The direction in which the detection light T is emitted is substantially parallel to the plane 112. The detection light T is received by the light receiving module 130 disposed in one of the detecting directions A to F, and generates an image signal. The light receiving module 130 is, for example, a group of image sensors, the number of which is not limited to one or more, and may be increased or decreased according to actual conditions. For example, six image sensors are respectively disposed in different detecting directions A~F. .

In the first and second figures, the image processing module 140 is electrically connected or wirelessly connected to the light receiving module 130 for receiving and processing the image signal, and measuring the underside of the object to be tested 10 by means of gap light image processing. A gap height G between the edge 12 and the plane 112. In an embodiment, the image processing module 140 receives and processes image signals of different detection directions. Since the detection values obtained in the respective detection directions A to F are different, the embodiment can transmit numerical values. Analyze and calculate the comparison to accurately know whether the gap height in each detection direction A~F meets the standard. The larger the value, the larger the gap height G, and the smaller the value, the smaller the gap height G.

For example, in an embodiment, the image processing module 140 can be connected to the external comparison module 150 or integrate the image processing module 140 and the comparison module 150 into a detection unit 132 in a built-in manner. When the gap height G is greater than a predetermined standard value, the comparison module 150 can send a failure detection signal according to the comparison result. If the gap height G is less than a preset standard value, the comparison module 150 can be compared according to the ratio. A qualified detection signal is sent to the result. In addition, if one or more gap heights in each of the detection directions A to F are greater than a preset standard value, the comparison module 150 may also issue a failure detection signal according to the comparison result.

The flatness detecting device 100 of the present embodiment may further include a dimming module 160 connected to the comparing module 150 and the light emitting module, in addition to the image processing module 140 for performing the gap optical image processing. Between the groups 120, the brightness of the light-emitting module 120 is adjusted to enable the image processing module 140 to perform processing under optimized image conditions to avoid detection under overexposure or insufficient brightness. The dimming mechanism uses a standard workpiece as the object to be tested 10, placed on the carrier platform 110, and is carried out under the condition that the gap height between the lower edge 12 and the plane 112 of the standard workpiece is known, and is known. The gap height is used as the standard value for dimming.

Please refer to FIGS. 1 and 3 , wherein FIG. 3 is a flow chart of a dimming method according to an embodiment. In step S30, the image is captured to perform image processing of the gap light. Step S32 is for performing numerical analysis to calculate the gap height between the lower edge 12 of the object 10 and the plane 112. Step S34 is inputting one The gap standard value is in step S32 to perform the operation comparison of step S36. In step S36, when the error value between the gap height G and the standard value is less than a ratio (for example, less than 1%) with respect to the standard value, it is determined that the brightness of the light-emitting module 120 is in an ideal state, as in step S38. On the other hand, if the error value between the gap height G and the standard value is greater than or equal to a ratio (for example, greater than 1%) with respect to the standard value, then the brightness is adjusted in step S40, and after the brightness is adjusted, the step S42 is performed again. Capture images. The loop of the above steps S32, S36, S40, and S42 may be performed one or more times until the brightness of the light emitting module 120 is in an ideal state.

Next, please refer to FIG. 4 and FIG. 5 , wherein FIG. 4 is a flow chart of a method for processing a gap light image according to an embodiment of the invention, and FIG. 5 is an enlarged schematic view of a gap light image. Step S50 is to capture the gap light image. Step S52 searches for the lower edge of the bright-grain signal M as a lower reference line S1 according to a bright-grain signal M representing the gap height in the image signal. The lower reference line S1 is also the reference line formed by the first edge corresponding to the plane 112 of the carrying platform 110 in FIG. Step S53 determines the first pixel position, for example, P1, to start the numerical operation. Step S54 finds a punctuation point, such as (X1, Y1), intersecting the upper edge of the bright-grain signal M (that is, the second edge corresponding to the lower edge 12 of the plane 112) along the direction of the vertical reference line S1. Step S55 is to calculate the distance between the coordinate point and the reference line S1 as the first gap height G1. Step S56 determines the next pixel position, for example, P2, P3, and returns to step S54, and repeats step S54 and step S55 at least once to find corresponding coordinate points, such as (X2, Y2), (X3, Y3). And calculating the distance between each coordinate point and the reference line S1 as the second gap height G2 and the third gap height G3, straight The average gap height of the interval is calculated until the measurement of multiple coordinate points in one interval is completed. Suppose that 10~30 pixels are used as an interval unit, first calculate the distance between a punctuation point and the reference line S1, and then move 1~3 pixels on the reference line S1 to calculate another coordinate point to the reference line S1. The distance between them. After the measurement of the plurality of coordinate points is completed, the average distance between the coordinate points and the reference line S1 is calculated. And so on, after the measurement of the entire bright line is completed, step S58 is performed to determine whether the distance meets the set value. For example, it is determined whether the minimum gap height is less than a standard value, whether each gap height is smaller than a standard value, or whether the gap height average of each section is smaller than a standard value. In one embodiment, if the determined distance is greater than the standard value, it is determined to be unsatisfactory, and if the determined distance is less than the standard value, the determination is deemed to be acceptable.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

10‧‧‧Test object

12‧‧‧ Lower edge (near the side of the plane)

100‧‧‧ flatness detection device

110‧‧‧Loading platform

112‧‧‧ plane

114‧‧‧ side wall

120‧‧‧Lighting module

122‧‧‧Lighting elements

130‧‧‧Light receiving module

132‧‧‧Detection unit

140‧‧‧Image Processing Module

150‧‧‧ Alignment module

160‧‧‧ dimming module

A~F‧‧‧Detection direction

L‧‧‧Light

M‧‧‧ bright grain signal

S1‧‧‧ baseline

T‧‧‧Detecting light

P1, P2, P3‧‧‧ pixel location

G, G1, G2, G3‧‧‧ gap height

(X1, Y1), (X2, Y2), (X3, Y3) ‧ ‧ punctuation

FIG. 1 is a block diagram showing a flatness detecting device according to an embodiment of the invention.

FIG. 2 is a schematic diagram showing the internal structure of the carrying platform in an embodiment.

FIG. 3 is a flow chart showing a dimming method according to an embodiment.

4 is a diagram showing gap light image processing according to an embodiment of the invention. Flow chart of the method.

FIG. 5 is an enlarged schematic view showing a gap light image.

10‧‧‧Test object

12‧‧‧ Lower edge

100‧‧‧ flatness detection device

110‧‧‧Loading platform

112‧‧‧ plane

120‧‧‧Lighting module

122‧‧‧Lighting elements

130‧‧‧Light receiving module

132‧‧‧Detection unit

140‧‧‧Image Processing Module

150‧‧‧ Alignment module

160‧‧‧ dimming module

L‧‧‧Light

T‧‧‧Detecting light

G‧‧‧ gap height

Claims (15)

A flatness detecting device includes: a carrying platform having a plane for carrying a test object and for transmitting a light; and a light emitting module disposed in the carrying platform for emitting the light, the light A detection light is generated by the object to be detected from the side of the plane and the plane; a light receiving module is located on one side of the carrier platform for receiving the detection light and generating an image signal; The image processing module is configured to receive and process the image signal to measure a gap height between the side of the object to be tested and the plane, and the image processing module is coupled to a comparison module. The module outputs a detection signal according to the ratio of the gap height to a standard value to determine whether the gap height meets the standard; and a dimming module connected to the comparison module and the illumination module For adjusting the brightness of the light-emitting module. The flatness detecting device of claim 1, wherein a side of the object to be tested near the plane is a lower edge of the object to be tested. The flatness detecting device of claim 1, wherein the light receiving module receives the detected light in a direction substantially parallel to the plane. The flatness detecting device according to claim 1, wherein the known gap is when the height of the gap between the side of the object to be tested near the plane and the plane is a known gap height. Height as The standard value, and the dimming module adjusts the brightness of the light emitting module according to an error value between the gap height and the standard value. The flatness detecting device according to claim 1, wherein the image processing module searches for the first edge of the plane corresponding to the bright signal according to a bright signal representing the height of the gap in the image signal. a reference line, and then finding a punctuation point intersecting the second edge of the side corresponding to the bright-grain signal along the direction perpendicular to the reference line, and calculating a distance between the coordinate point and the reference line as the reference line Clearance height. The flatness detecting device of claim 5, wherein the first edge of the bright-grain signal corresponding to the plane is the lower edge of the bright-grain signal, and the second edge of the bright-grain signal corresponding to the side is The upper edge of the bright signal. The flatness detecting device according to claim 5, wherein the image processing module calculates an average gap height of the interval according to a distance between the plurality of coordinate points in the interval and the reference line. The flatness detecting device of claim 1, wherein the light emitting module comprises a plurality of light emitting elements, the light emitting elements surround the inside of the carrying platform, and emit light directly toward the plane of the carrying platform, or It is illuminated toward the side wall and directs light to the plane by reflection. A flatness detecting method includes: placing a test object on a plane of a carrying platform; adjusting a brightness of a light and causing the light to be emitted from the side of the object close to the plane and the plane to generate a Detecting light; Performing an image processing on the detection light to measure a gap height between the side of the object to be tested near the plane and the plane; and generating a detection signal according to the ratio of the gap height to a standard value. To determine whether the gap height meets the standard. The flatness detecting method according to claim 9, wherein the side of the object to be tested near the plane is the lower edge of the object to be tested. The flatness detecting method according to claim 9, wherein the direction in which the detecting light is emitted is substantially parallel to the plane. The flatness detecting method according to claim 9, wherein when the height of the gap between the side of the object to be tested and the plane is a known gap height, the known The gap height is taken as the standard value, and the brightness of the detection light is adjusted according to an error value between the gap height and the standard value. The method for detecting a flatness according to claim 9, wherein the performing the image processing comprises searching for a first edge of the plane corresponding to the brightness signal according to a brightness signal representing the height of the gap in an image signal a reference line, and then, along a direction perpendicular to the reference line, a punctuation point intersecting the second edge of the side corresponding to the bright-grain signal is found to calculate the distance between the coordinate point and the reference line as the reference line Clearance height. The method for detecting a flatness according to claim 13 , wherein the first edge of the bright-grain signal corresponding to the plane is the lower edge of the bright-grain signal, and the second edge of the bright-grain signal corresponding to the side is The upper edge of the bright signal. The method for detecting a flatness according to claim 13 wherein the image processing comprises performing a plurality of coordinate points according to an interval. The distance from the baseline is calculated as the average gap height of the interval.