JPH03218407A - Shape measuring device, shape measuring method and correcting method for shape measuring device - Google Patents

Abstract

PURPOSE:To measure the shape of an object to be measured with a soldering surface in a mirror state by successively turning on/off plural light sources at various positions one by one, executing image pickup synchronously with turning-on and storing plural picture data. CONSTITUTION:On a semispherical cover 1 to shield disturbance light, plural LED 2 are arranged and a board (a) is mounted while providing an X-Y table 4 in the lower direction of the cover 1. A controller 3 drives the table 4, matches the position of a part to be measured to an image pickup position, successively turns the LED 2 on one by one along the lead direction of electronic ports soldered to the board (a), successively picks up the image of a picture at a soldering part irradiated with each LED by a camera 5 synchronously with turning-on, transmits the picture data to a picture processor 6 and stores the data. The processor 6 calculates the inclination of the object to be measured from a relation between the position of the light source LED and the position of the camera 5 respectively corresponding to the plural picture data and can measure the shape.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a shape measuring method, and particularly to measuring objects having a mirror surface, such as solder for bonding electronic components onto a board. -Relates to a shape measuring device for inspection, a shape measuring method, and a method of calibrating the shape measuring device.

(Prior Art) Conventionally, inspection of soldering conditions has mainly relied on visual inspection. In recent years, in an effort to eliminate such manual work, inspection devices and shape measuring devices for automation have been developed.

First, as shown in Figure 12, light is irradiated obliquely,
A device that detects the reflected light is being considered.

This is because, as shown in Figure 13, if there is no solder, the light will not be reflected directly above, so if you try to view it from directly above, the screen will be dark. If there is solder on it, it will be brighter. The way the solder is attached is detected from the degree of brightness and darkness.

However, although this method can detect the presence or absence of solder, it is difficult to detect excess or deficiency in the amount of solder. Furthermore, it is affected by the surface condition of the solder, making it unreliable and impractical.

Next, shape measurement using optical cutting as shown in FIG. 14 has been considered. An image of the part to be measured is obtained by scanning the part to be measured with a slit light or spot light at an angle different from the direction in which the light is incident. This image is used to measure the shape of the soldered state.

However, if the object has a normal diffuse reflection surface, no problem will occur, but since the surface of solder becomes mirror-like, the following problems occur, making it unsuitable for practical use.

First, due to the mirror surface state, there are parts where a single camera cannot recognize the reflection of light incident from an angle. Second, there are aspects that are not practical, such as a long detection time.

Next, it is conceivable to apply a stereo illuminance method such as that disclosed in Japanese Patent Application Laid-Open No. 63-76073 "Shape Measuring Apparatus".

This stereo illuminance difference method creates an illuminance difference map by sequentially switching a plurality of light sources to provide illumination. The inclination of the object to be measured corresponding to each pixel is determined from this illuminance difference map, and the shape is detected by connecting these inclinations.

However, the solder surface has reflective properties similar to a mirror surface. Therefore, unlike a completely diffused surface, which is a condition for using the stereo photometric method, detection is difficult. This is because in the stereo photometric method, the illuminance varies depending on the inclination of the surface with respect to the direction in which light is irradiated, that is, the shape is measured using the illuminance difference. Therefore, if the surface of the object is a mirror surface, almost no light will be reflected in the direction of the imaging means due to the different inclinations. Therefore, the image obtained by the imaging device is not an image with a difference in illuminance, but only a binarized image. In other words, in such a state, it is not possible to obtain the illuminance difference required by the stereophotometric method, so it is difficult to measure the shape of an object with a mirror surface, such as solder, using this method.

Furthermore, in the stereo photometric method, it is necessary to memorize the illuminance of the inclination of the target substance in advance. Therefore, the reliability of measurement accuracy becomes low for objects whose surface characteristics change, that is, objects whose surface conditions change depending on the gloss or amount of flux, such as solder.

(Problems to be Solved by the Invention) As described above, conventional soldering inspection and shape measuring devices and methods have been unable to handle various inspection items of soldering conditions, or have been difficult to measure.

The present invention is directed to a shape measuring device that can accurately measure the shape of objects such as solder, which have an almost mirror-like surface, which has been difficult to detect and measure in the past, and a shape measuring device used in this device. provide a method.

Furthermore, a configuration method essential to such a shape measuring device is provided.

[Structure of the Invention] (Means for Solving the Problems) A mounting table on which an object to be measured is placed at a predetermined position, and an object to be inspected on the mounting table from a plurality of predetermined positions above the mounting table. A plurality of light sources that can irradiate light onto an object at a predetermined angle, a light source control means that can independently turn on any one or more of the plurality of light sources, and the part to be measured that is illuminated by the light source. one or more imaging means for capturing an image including the image from a predetermined position; a storage means for storing image data captured by the imaging means; and one or more imaging means for capturing an image including Issue a command to turn on the light source, capture image data from the imaging means in synchronization with the lighting of the light source, store it in a predetermined address of the storage means, and measure and measure the shape based on the single or plural image data stored. This is a shape measuring device equipped with arithmetic control means for performing recognition or inspection.

Further, it is a shape measuring device in which the imaging means changes the vertical and horizontal magnification ratio according to the object to be inspected.

In addition, the distance and size of the light sources and the light reception level are set so that each of the multiple light sources has a known width of angular information, and the width of this angular information partially overlaps with the width of the angular information of other light sources. This is a shape measuring device.

Furthermore, the following three shape measurement methods used in connection with the above-mentioned shape measurement device and a method that is a partial improvement thereof are provided.

The first method is to turn on only one light source at an arbitrary position,
A single light source lighting process in which the light sources in other positions are turned off and the light sources in different positions are blinked sequentially in a predetermined order, and this is synchronized with the lighting of the single light source turned on in this single light source lighting process. an imaging step in which the image data obtained in the imaging step is sequentially captured by the imaging device; a storage step in which the image data obtained in the imaging step is sequentially stored in the storage device; and a position of a light source corresponding to each of the plurality of image data stored in the storage step. A shape measuring method comprising a shape measuring step of determining the inclination of an object to be measured corresponding to a pixel on an image from the relationship with the position of an imaging device, and measuring the shape from the inclination of the object to be measured corresponding to this pixel. It is.

The second method consists of a light source lighting process in which light sources in multiple positions divided into predetermined blocks are turned on and light sources in other positions are turned off, and a single light source turned on in this light source lighting process. an imaging step in which images are taken sequentially by an imaging means in synchronization with the lighting of the , a storage step in which image data obtained in this imaging step is sequentially stored in a storage means, and image data stored in this storage step is used in the lighting step. Classify bright points on the image that correspond to lit light sources, and? The inclination of the object to be measured corresponding to the pixel on the image data is determined from the relationship between the position of the light source and the position of the imaging device corresponding to each of the number of image data, and the inclination of the object to be measured corresponding to this pixel is determined. This is a shape measuring method comprising a shape measuring step of measuring a shape from.

The third method is to divide the light source into a plurality of blocks in advance, set up a group in advance in which one or more blocks of this light source are combined so that they overlap, and turn on these groups one after another. A group light source lighting step, an imaging step in which images are sequentially taken by an imaging means in synchronization with the lighting of a single light source turned on in this group light source lighting step, and image data obtained in this imaging step is sequentially stored in a storage means. an image calculation step of calculating the plurality of image data stored in this storage step and extracting image data when each block of the light source independently illuminates the object to be inspected; When each block obtained in the process illuminates the object to be measured, the bright points in the image data are classified as to which light source in the same block was illuminated, and it also corresponds to each of multiple image data. a shape measuring step of determining the inclination of the limb measurement object corresponding to the pixel on the image from the relationship between the position of the light source and the position of the imaging device, and measuring the shape from the inclination of the object to be measured corresponding to this pixel. This is a shape measurement method.

Furthermore, in the shape measurement process of the above three shape measurement methods, the present invention is capable of determining the authenticity of the tilt of the object to be measured corresponding to the determined pixel by comparing it with pre-stored reference data. This is a shape measurement method that has the additional feature of performing.

In addition, as a method for calibrating the positional relationship between the light source means and the imaging means of the above-mentioned shape measuring device, a reference object to be measured whose shape is known in advance and whose surface is almost a mirror surface is placed on the above-mentioned mounting table, and an arbitrary The light source at the position is turned on, the image data at this time is obtained by the imaging means, and the relationship between the light source position and the imaging position 1'wt is determined based on the bright position of the image data at this time and the shape data of the reference object to be measured. This is a method for calibrating a shape measuring device to be calibrated.

(Function) By providing such a means, it is possible to accurately measure the shape of an object having a mirror-like surface, such as solder. The principle of this shape measurement will be explained using FIG.

First, a light source irradiates the object to be measured, and an image is captured. The captured image captures light specularly reflected on the solder surface. That is, bright points in this image can be obtained as tilt information from the positional relationship between the light source position and the imaging device. Therefore, this slope information is θ. -90- (θ1+θ1)/2... (1)
, is calculated using the formula. That is, the inclination θ of a bright point in the captured image is determined from the predetermined incident angle θ1 of the light from the light source to the object to be measured and the angle θ of the imaging device.

Next, the position of the light source is changed, and the image after the change is captured by the imaging device. At this time, by changing the position of the light source, the angle of incidence of the light on the object to be measured is 0.1. , changed to .

In other words, the slope θ of the bright point of the image captured at this time
1. , is θ. ．． ,=90− (θ1+01.1)/2
...It is found by (1').

Similarly, θ, . Find θ4,..., θ8.

Next, the slope θ,, θ2. ..., the shape of the surface of the object to be measured from which θ8 was determined is determined. Information in the height direction is required when measuring the shape.

Here, the external shape of the measurement target is given by arbitrary coordinates (x, y)
When the height of is 2, z=f (x, y) ... is expressed by the equation (2).

This equation can be obtained by integrating the slope.

In order to recognize shapes from such images, let's consider overlapping each image. If the bright points are connected continuously as shown in Figure 2, the slope of each bright point is θ1,
θ2. ..., e1, the height information can be calculated in order to easily detect the shape. However, in order to detect in this way, it is necessary to collect each data when the position of the light source is continuously changed, which is not very practical at present. Therefore, when actually performing measurements, sparser sampling points are taken. In other words, when the captured images are superimposed,
The image will look like the one shown in Figure 3. Even if the angles of such sparse points are known, the shape cannot be measured unless it is converted into height information. Therefore, focusing on the fact that the solder is solidified from a molten state, the slope of the surface can be recognized as a shape that normally changes continuously. Therefore, an approximate expression is found from these sampling points. This approximate expression can be considered to be equivalent to equation (2) representing the shape of the object to be measured.

Furthermore, it is assumed that the light source has a sufficient distance from the object to be measured and that the object is small. If the light source is close, the angle of incidence of light at the periphery of the object to be measured will be different, and the above equation (1) will not be satisfied.

Therefore, by keeping a sufficient distance from the object, the inclination of the angle of incidence of light at the center and the sides can be ignored. Of course, unless the object to be measured is small, no matter how far the distance from the light source is, there will still be angle differences in the incident light around the periphery, making accurate measurement impossible. Therefore, the above-mentioned premise is necessary. However, the difference between the irradiation angle between the center and the periphery depends on the allowable error range of shape measurement accuracy, the position and size of the illumination, and related values such as the relative distance to the object to be measured. The correction may be made by calculation.

Moreover, the expression (1) is satisfied here when the light source is a point light source. In order to actually realize a device that emits a point light source, a new light source must be designed, which is not very practical in terms of technology and production cost. Therefore, a commonly used light source with a certain size may be used. However, in this case, since the light source has a certain size, the irradiation angle varies. Therefore, the bright spot on the screen depends on the size of this light source.
= (9(1- (θ, 10.)/2) ±α...
(3) The angle information has a range of inclination. Further, the width of this inclination is influenced by the size of the light source itself, the distance to the limb measurement object, and the sensitivity and binarization level of the light receiving element during image processing.

In this case as well, the shape can be measured in the same manner as described above, but the width of this inclination can be used to further improve the measurement accuracy.

For example, assume that the light source A is placed at an angle of 30 degrees with respect to the limb measurement target. The size of the light source A and the distance to the object to be measured are set so that the light source A has an irradiation angle range of ±5 degrees.

Then, when we obtain image data A that captures the limb measurement object illuminated by this light source A at 90 degrees to the object to be measured, that is, from directly above, the bright points of this image data A due to the illumination are as described above. According to formula (3), (9G − (900 Hl) /2) ±5= (
9G-60+ ±5 = 30±5. Next, place light source B at an angle of 50 degrees with respect to the object to be measured, and adjust the size of light source B so that it has the same irradiation angle width of ±5 degrees as the previous light source. Set the distance to. Image data B at this time is calculated from the above equation (3) as follows: {90- (90+5G) /2+ ±5= (90-
70) ±5 = 20±5. That is, the angle information of the bright points of image data A is 25 degrees to 35 degrees, and the angle information of the bright points of image data B is 15 degrees to 25 degrees. When image data A and image data B are combined, the result is as shown in FIG. 22.

Here, a set of bright points A of image data A and image data B
The area AB that overlaps with the bright point set B has these two pieces of information at the same time. That is, area 8B has an angle of 25 degrees. Here, if a similar light source C is arranged to irradiate the object to be measured at an angle of 70 degrees, the area [IC] will have angle information of 35 degrees. In this way, with a point light source, only the inclination of the object to be measured is 1, which corresponds to the angle at which the object is irradiated.
However, by using a light source and adjusting its size, it is possible to detect pixels that have an inclination of the object to be measured depending on the irradiation angle between it and the other light source. It is. Of course, matching is not limited to adjacent light sources. It is also possible to calculate the inclination of the object to be measured according to the pixel by superimposing two and three pixels and calculating the image data.

Furthermore, if it is possible to separate the light sources projected onto the object to be measured, it is possible to simultaneously irradiate the object with multiple light sources, image it, separate and recognize the light sources from the image after the image is taken, and perform image processing to shape the object. Measure. This reduces the number of times of imaging and shortens the measurement time. This takes advantage of the fact that the time it takes to process most of the image once is extremely short compared to the time it takes to image one screen, and by reducing the number of images taken and increasing the number of image processing, the final result can be improved. This shortens the measurement time.

In addition, as a method to reduce the number of images taken and to shorten the measurement time, the entire plurality of light sources can be classified into several blocks, and several groups consisting of some of these blocks can be constructed, and the light source group is irradiated. There is a method to computationally separate images for each block by taking a difference image of the images when This means, for example, that the entire light source is AB
When divided into three blocks C, image data 1 illuminated by group 1 made up of light source blocks AB, and image data 2 illuminated by group 2 made up of light source blocks AC. Suppose you get it. When performing calculations between image data AB and image data AC, image data A when illuminated by light source block A is obtained under the AND condition, and image data A is subtracted from image data AB or image data AC. As a result, image data B or image data C when illuminated by light source block B or light source block C can be obtained. By doing so, it is possible to reduce the number of times of imaging and shorten the measurement time.

Further, depending on the object to be measured, resolution may be required in a specific direction. However, this resolution is determined by the number of pixels of the light-receiving element, which is the light-receiving part of the imaging means, or the number of scanning lines of the light-receiving tube. The only option was to use a light receiving section with a large number of lines. However, there are technical limits to using a light receiving section with a large number of pixels or scanning lines.
Usually this involves enlarging the screen. However, when measuring the leads of a semiconductor chip, enlarging the screen reduces the number of leads that can be included in the image data obtained from one image capture, resulting in an increase in the number of image captures. , which increases the measurement time. Therefore, by changing the vertical and horizontal magnification ratio using the optical system, it is possible to magnify only the direction that requires resolution, and not to expand in directions that do not require much resolution, or to magnify at a lower magnification ratio than in the direction that requires resolution. Alternatively, the measurement is performed using an optical system that reduces the size within a range that has the minimum magnification that does not affect the measurement.

In addition, in order for such a new shape measuring device to operate correctly, its reliability is achieved only when the relationship between the light source position and the imaging position is correctly recognized.

As a calibration method for this purpose, it is necessary to configure a measurement reference object with a known shape in advance. The reference body to be measured may in particular be of spherical or hemispherical shape. For example, using a polyhedron as the reference object to be measured has the advantage that the reflective area is a surface, making it easier to see, but the light source is not a perfect point source and usually has a size, so the area to be reflected is a surface. It is not possible to perform calibration that takes into account the delicate size of the light source, that is, the angular width of the incident light. In other words, if the light is within the range of ±α in equation (3) above, it will be reflected by the surface that should reflect it, making it impossible to calibrate the range of ±α. In this respect, by using a spherical or hemispherical reference object to be measured, the irradiation angle and size of the light source can be clearly recognized.

Further, even if the object to be measured has a mirror surface, scattered light may occur. Therefore, it is necessary to adjust the light receiving level which is affected by such scattered light. This light reception level includes the light reception level of the light receiving element itself of the imaging means, and the binarization level when performing image processing, for example, when performing binarization.

(Hereinafter, blank space) (Example) A first example of a shape measuring device using the shape measuring method of the present invention will be described below with reference to the drawings.

FIG. 4 is a configuration diagram of the first embodiment. A semicircular spherical cover that blocks external light (+1 and L E D (2+) are placed every 1 degree in the meridian direction and every 5 degrees in the latitude direction. It is connected to a control device (3) so that it can be turned on by turning it on.Below the cover (1) is an X-Y table (on which the board is placed).
4) is provided. Also, this X-Y table (4
) is controllably connected to the control device N(3). Furthermore, a camera (5) is arranged in the perpendicular direction of the cover (1). This camera (5) is connected to be able to transmit the captured image signal to the image processing device 11 (fit), and the image processing device (61) is further connected to be able to display the processing results on the monitor (7). Also, the image processing device! (6) and the monitor (71 are the control device fi (
It is connected to operate according to the command of No. 31.

Next, the operation of the method of the present invention will be explained using this apparatus. First, a board (a) to which an electronic component, which is an object to be measured, is soldered is placed on an X-Y table (4). substrate(
8) is placed, the control device (3) moves the X-Y table (
4) so that the soldering part is placed in the center of the screen imaged by the camera (5). This is prepared in advance on the substrate (al
is positioned on the X-Y table (4), and the X-Y table (4) is driven based on that information.

After aligning the part to be measured with the imaging position in this way, the control device N (3)
D (Light up one row along the lead direction of the electronic components No. 21 one by one from the top. At this time, each L
Images of the soldered part illuminated by E D (2) are sequentially captured by the camera (5). The screen at this time is the fifth
As shown in the figure.

Next, the image thus captured is transmitted as image data to the image processing device (6) and stored therein. Image processing device (6
), the shape is measured from this stored image data.

Here, bright point A in the image when light source (2a) is turned on
is shown in Figure 5. The eight tonshins (representative points) G, and the slope θ formed by the point A are determined. Similarly, the light source (2b
), (2cl,... bright points B, C,...
・I will seek. In addition, in the area where the slope is 0, that is, the substrate surface, the boundary between the solder and the substrate is determined using the epi-illumination mechanism built into the camera (5), and this boundary position is designated as G. shall be. This is shown in the table below.

At this time, θ is calculated backward from the position of the light source at the time of old imaging, as described in the section on effects above. Here G. l and G
l. Gl and G2. ...is not connected (1,
, so the midpoint C. between G1 and G1. 、． The midpoint between C.G and 62. , G2 and (;,... are calculated in sequence. Here, assuming that the slope of the plane from C1 to C2 is 02, the shape of the solder surface is measured.

Here, the midpoint C1 between GIT and G is assumed to be the start of the slope, but actually the slope starts from G11.

The slope from this G II to C I+ (0〈θ〈θ1)
and height shall be within the error accuracy. That is, C.
Instead of setting l, C II may be replaced with 6.1.

Here, the length from C1, to C1 is L, and from C, to C
Let the length up to 2 be L2. At this time, the height Z1 of C1 is Z, =L, X tanθ, ... (4)
It can be calculated by Hereinafter, the height Z2 of C2 is Z2 = L2
X tanθ2+ Z .・-(4M, the height Z of C1 is Z + = L 1 X lanθ1 +
Σ Z...(4') is calculated.

By connecting these detection results, the cross-sectional shape of the solder can be calculated as shown in FIG. In this Fig. 6, the rows of L E D f2) in the same direction as the leads are lit up in sequence, but by lighting up the other rows of L E D f2+, as shown in Fig. 7. It is also possible to detect the shape of the entire solder.

The above-mentioned inspection device requires that the LED as a light source be a complete point light source. However, in reality, the LED has a size as a light source, and therefore, the irradiation light is irradiated with an error of ±α. The problem in this case is that the brightly shining points overlap as shown in FIG. In this case as well, the center of gravity may be used as in the first embodiment. but,
Considering that this bright spot is information that contains an error, we will use a method to slightly modify it. Here, FIG. 8 shows a bright point A in the image when the light source (2a) is turned on. The center of gravity (representative point) G1 of this A,
Find the length of 8 along with the slope θ formed by A and A. Similarly, the bright points B, C, etc. for the light sources (2b), (2c), .・I will seek. This is shown in Table 2 below.

Table 2 Here A(!:B Intersection of B and C,... CI, C2
．． . . . In the first embodiment, the midpoint was simply found, but here the ratio of the lengths L1 and L2, L, and L3 is used. That is, c)=G,+(G2 Gl jxl,/(L.+L2
)C,=G2↓fGt-G, )xL2/(L,+l
) to find the intersection. By calculating the intersection point using the ratio in this way, in addition to the above-mentioned effect, an attempt is made to further reduce the error.

Next, a second embodiment of the present invention will be described. The configuration of the device is the same as that of the first embodiment, so a description thereof will be omitted.

The alignment of the target portion to be imaged is the same as described above. Here, the screen to be detected is input into the image processing device (3) using the camera (5), and the captured image data is divided into a grid pattern as shown in FIG.

Now, the control device (3) sequentially lights up the LEDs (21) one by one, and the image at this time is sent to the camera (5).
The images are sequentially stored in the image processing device W (6). At this time, the light intensity of the area divided into a grid is calculated for each captured image, and the brightest point or L corresponding to the strongest image is calculated.
Let the slope θ found from the position of E D f21 be the slope of that area. After that, height information is calculated from this inclination data, and a shape as shown in FIG. 10 is detected.

The difference from the stereo photometric method is that for one of the areas divided into a grid, the slope θ at the light source position with the largest number of bright pixels for all light source positions is the slope of that area. The purpose of this method is not to obtain illuminance differences due to changing the light source position, but rather to use the most common tilt in a region as a representative of that region.

As described above, by using the method of the present invention, it is possible to easily measure the shape of an object having a mirror-like surface.

A third embodiment of the present invention will be described below. The configuration of the device is the same as that in the first embodiment, so a description thereof will be omitted. When the target portion is aligned, the control device (3) turns on a plurality of LEDs (2). Multiple LEDs to be lit at this time
(2) It shall be located in such a way that it cannot be confused with. For example, if the matching meridian in the lead progress direction is O degrees, then L at a position of 0 degrees longitude and 70 degrees latitude.
Three L E D (2): E D (2) and L E D (2) located at ±20 degrees longitude and 20 degrees latitude.
lights up. At this time, the shape of the solder is F!
), you will get an image like Figure 16 (a+). If the shape of the solder is like Figure 17 (
If there is excess solder as shown in b), then the condition shown in Fig. 16(b)
), so it is difficult to determine which point of light is L E
It is possible to determine whether it corresponds to D (2). This is because, due to the nature of the solder object, it is almost impossible for the light spots of the two LEDs (2) located at ±20 degrees of longitude and 20 degrees of latitude to switch places. There is. Of course, many other combinations can be considered depending on the nature of the object.

Images obtained by combining such a plurality of illumination positions are stored in the image processing device (6), and by calculation, the shape can be measured in the same manner as in the first embodiment. This allows the number of times of imaging to be reduced and the measurement time to be shortened. To further facilitate separation, the color of the light source may be changed. For example, the colors of the light sources at adjacent longitudes or latitudes may be changed to achieve separation. Also,
There are other methods of separation. This will be shown below as a fourth example.

The configuration of the device is the same as that of the first embodiment, so a description thereof will be omitted. When the target part of the limb measurement object is aligned, the control device (3
) lights up multiple L E D (2+).

At this time, LED (2) arranged in the latitude direction at 5 degree intervals from 20 degrees to 90 degrees is LED (2-1),
LED f2- 21, ..., L E D f2
-+5), the first lighting will turn on the odd numbered L E
D (2-1), (2-3). ... (2-15
Turn on +. This is imaged by the camera (5),
It is stored in the image processing device (6). The image at this time is the first
It is shown in Figure 8 fa). Then, in the second lighting, L
E D (2-21. (2-3). (2-6).
(2-7). (2-10). (2-1+) (2-1
41. (2-15) is turned on and stored in the image processing device (6) in the same manner as described above. The image at this time is shown in Figure 18 (
Shown in bl. Furthermore, the third time is L E D (2-4
). ..., +2-7). f2-12),...
+2-15), and the fourth time was (2-8)... (
2-15) are turned on and stored in the image processing device (6) in the same manner as described above. The image at this time is shown in Figure 18(c).
, shown in (d). The captured images and L are shown in Table 3 of Figure 27.
E
E D (2-2), +2-6+. (2-10+
．． +2-14) bright points are extracted. Conversely, by obtaining an image obtained by subtracting the second image from the first image, 1, E D (2-1). f2-5).
A bright point of (2-9+. f2-15) is extracted.

Also, when determining the overlapping portion of bright pixels between the first image and the second image, LED (2-3).
(2-7). (2-II). A bright point at f2-15) is extracted. By using these extracted results, (2-4) from the third image. f2-12) is
(2-8) can be extracted from the fourth image.

By performing calculations between images in this way, L E
D (2-1) (2-2). H-3). ...
, (2-151) can extract the bright points when each is illuminated independently, and based on this extracted data, the shape of the object to be measured is measured by the inclination of the pixel. The measurement principle is the same as that of the first embodiment. Since it is the same as , the details are omitted.This reduces the number of times of imaging and shortens the measurement time.

Next, a fifth embodiment of the present invention will be described. In the first to third embodiments described above, only shapes that are very easy to measure have been described as examples for the sake of explanation.

However, in actual measurements, large and small noises, which have been ignored in the explanation of the embodiments so far, are easily detected, and it is impossible to make accurate measurements without considering the influence of this noise. be. In this fifth embodiment, how to reduce the influence of noise will be explained as follows.

The configuration of the device is the same as that of the first embodiment, so a description thereof will be omitted. When the target part of the limb measurement object is aligned, the control device
! (3) lights up any one of L E D (2). At this time, assume that multiple bright dots appear on the image as shown in Figure 19. Small dots are removed by noise removal, that is, reduction.・Delete by performing expansion process.However,
If noise occurs that cannot be removed even then, this noise will have a great effect on shape measurement. Here, if the condition that the shape of the object to be measured is similar to the basic shape is satisfied to some extent, such as solder, the conditions that the basic shape can have and the image obtained from the object are measured. The data are compared and the authenticity of the image data obtained from the measured λ1 object is determined. For example, the shape of a fillet of solder is concave. That is, when turning on the light source (2), the tightness is 10 degrees sequentially from 80 degrees to 20 degrees latitude.
If the lights are turned on every ', the bright spots in the image obtained from the limb measurement object should appear in order from the smallest to the largest inclination when each image data is superimposed. In other words, if there are multiple bright points in the image data of the object to be measured obtained using an arbitrary light source, the bright points existing between them are considered to be true for the image data obtained before and after the source. , other cases are ignored and the shape measurement is performed. Also, if several bright points exist between the bright points of the previous and subsequent data, the bright point that is closer to the ideal value is determined to be the true bright point, and the others are ignored during measurement. I'll decide.

That is, when a plurality of bright points appear in the image data of the object obtained by an arbitrary light source, the true bright point is determined based on the positional relationship with the bright points in the image data before and after it. The reference shape data used for judgment at this time may be actually compared using image data actually obtained from non-defective products, or may be calculated using theoretical or ideal value data or design data. Good too.

Next, a sixth embodiment will be explained. The feature of the sixth practical example lies in the human-powered device for the image instead of the shape measuring method. Therefore, since the configuration of the entire shape measuring device is the same as that of the first embodiment, it will be omitted, and the configuration of the imaging means will be mainly explained. As shown in FIG. 20, a cylindrical lens (5a) is arranged in a part of the optical system of the camera (5). This cylindrical power lens (5a) is rotatably provided independently of other optical systems, and is rotated by a motor (5b) to rotate the cylindrical power lens (5a) at any angle.
) is configured so that the direction can be controlled. motor(
5b) Connected to the control unit (3) so as to be able to control other rotations.

Next, the operation of the sixth embodiment will be explained. As the object to be measured, the shape of the solder on the lead part of the QFP is measured. Figure 21(a) shows an image taken using a normal imaging means without a linear lens.
Figure 21(b) shows an image taken by the imaging means using a).
Shown below. Here, Q F r) The important part when measuring the shape of the solder in the glue part is the shape of the back part of the solder fillet shown by the broken line in the figure. However, in an image captured using only a conventional imaging optical system, the resolution of the image in the direction of the broken line is determined by the number of pixels of the light receiving element of the imaging means (or the number of scanning lines in a camera using an imaging tube).

Therefore, in order to improve the resolution, it is necessary to enlarge the measurement site as much as possible and image it. However, as mentioned above, the time taken to capture an image is the most time-consuming part, and if the magnification of the imaging means is increased to increase resolution, the number of leads that can be imaged at one time will be reduced. Therefore, by incorporating a cylindrical lens (5a) into the optical system, magnification is performed only in the direction of the broken line where resolution is required, and imaging can be performed as normal in the direction orthogonal to the broken line. When inspecting a QFP facing in another direction, it is sufficient to drive the motor (5b) and rotate the cylindrical drill lens (5a) by 90 degrees.

Next, a seventh embodiment of the present invention will be described. The basic configuration of the shape measuring device in the seventh embodiment is the same as that in the first embodiment, so a description thereof will be omitted. The difference between the seventh embodiment and the first embodiment is that the L E attached to the cover (1) in the first embodiment is
D (2) is attached every 10 degrees in the meridian direction and every 5 degrees in the latitude direction, whereas in the sixth embodiment, it is attached every 20 degrees in the latitude direction. In addition, the tilt angle information of the object to be measured corresponding to the bright point in the image data obtained when one of the light sources LED (2) is turned on to illuminate the object to be measured is determined based on the set irradiation angle. The corresponding tilt angle is set to be ±7 degrees. This setting depends on the distance between the light source L E D (2) and the object to be measured, the size of L E D (2), and the camera (5
) and the binarization level. After the object to be measured is positioned at a predetermined position, the LEDs (2) are sequentially turned on, and image data is captured by the camera (5) in synchronization with this. The captured image data is processed by an image processing device (6). Here, to avoid this calculation, L E D i2) located at IO degrees, 30 degrees, and 5a degrees in the latitude direction
Taking as an example three image data obtained when turning on the
This will be explained using FIG. 23. The angle information of the inclination of the limb measurement object corresponding to the bright point on the image data obtained when LED f2) located at a position of 10 degrees in the latitude direction is turned on is from 33 degrees to 47 degrees. The angle information of the inclination of the object to be measured corresponding to the bright point on the image data obtained when LED (2) located at a position of 30 degrees in the latitude direction is turned on is from 23 degrees to 37 degrees. The angle information of the inclination of the object to be measured corresponding to the bright point on the image data obtained when LED (2) located at a position of 50 degrees in the latitude direction is turned on is from 13 degrees to 27 degrees. Therefore, the points where the bright points of these two image data overlap are 10 degrees and 3 degrees.
The angle information of the overlapping part based on LED (2) at the position of 0 degrees is 33 degrees to 37 degrees, and the angle information of the overlap part according to LED (2) at the positions of 30 degrees and 50 degrees is 23 degrees. Set a circle that is inscribed in these two overlapping parts.The center is on the line segment that connects the centers of these circles, and the L is 30 degrees.
A circumcircle included in the bright area of the image data obtained by E D (2) is set. The angle information of the area surrounded by this circumscribed circle is from 28 degrees to 32 degrees. In other words, if we take the angles of the area surrounded by these two duplicated areas and the circumscribed circle as the center of the angle information and set them as 25 degrees, 30 degrees, and 35 degrees in order from the lowest angle, the measurement accuracy for every 5 degrees The shape can be measured with . Others ED (
2) By doing the same for all the shapes, it is possible to measure the overall shape with a measurement accuracy of every 5 degrees.

Next, a method for calibrating a shape measuring device will be described using the first embodiment of the present invention. First, a hemispherical measurement reference body S as shown in FIG. 24 is placed as an object to be measured by the shape measuring apparatus of the first embodiment. The surface of the measurement reference body S is made of the same material as the object to be measured measured by the shape measuring device or a material having the same reflectance. Furthermore, this measurement reference body S is placed on a diffuser plate, and this diffuser plate is configured to emit light from the entire diffuser plate by turning on a light source (not shown).

The operation of the method for calibrating a shape measuring device according to the present invention will be explained below. First, a light source (not shown) is turned on, and an image is taken with the camera (5) while the entire diffuser plate emits light. The image at this time is shown in FIG. In this image, the measurement reference body S is in the shadow, so the center of gravity of the measurement reference body S is determined by the image processing device (6), and the position of this measurement reference body S is recognized. Next, turn off the light source (not shown) on the diffuser plate, and turn off the camera (5
) An LED (not shown) that can be epi-illuminated by a half mirror (not shown) inside is turned on, and the measurement reference body S at this time is imaged by the camera (5). At this time, if the camera (5) is placed correctly, the center of the bright spot on the image data at this time will coincide with the center of gravity of the measurement reference body S. If they do not match, the position of the camera (5) is corrected so that they match. Bright spots due to epi-illumination,
After matching the center of gravity of the measurement reference body S, L E D (
2) are turned on in sequence. At this time, the position of the bright spot appearing on the image data is compared to see if it is at the position predicted by calculation based on the angle of the camera (5) and the L E D r2) with respect to the hemispherical shape, and the installation position of the L IE D f2+ is determined. Or is it correct? ．． l1 is determined. At this time, if the predicted position and the actual bright point position are different, then L
E D (Correct the position of 2+ or use the image processing device (6
), correct the installation angle of ED (2).

After that, as shown in FIG. 26, the LED f2+ is repeatedly turned on in order to make corrections.

Also, at this time, the width of the angle information of the object to be measured corresponding to the bright point based on L E D (2) is set.

As a shape measuring device, since the distance between the light source and the object to be measured and the size of L E D f2) are already determined, here we will use the sensitivity of the light receiving element, that is, the image data captured by the camera (5). By setting the binarization level of , the width of the angle information is changed.

In addition, in the above-mentioned first to seventh embodiments, for the sake of explanation, embodiments were described in which only one imaging device was used, but such a single imaging device naturally creates a blind spot in the measurement range. Therefore, a plurality of imaging devices may be used as shown in FIG. 11. Even in such a case, all of the above embodiments can be applied by simply changing the conditions stored in the image processing device in advance.
iJ Noh.

Furthermore, in FIG. II, the arrangement of the LEDs may be changed to an epi-illumination type using a half mirror without using a transmission hole for the imaging device. Since this epi-illumination may be one used in ordinary optical microscopes, no particular explanation will be provided. Further, when measuring the shape using only the light source of the number of funerals, a movable type as shown in FIG. 12 may be used instead of a fixed type as in this embodiment.

Note that in the explanation of the operation of this embodiment, only one object of shape measurement is described, but this is for the purpose of simplifying the explanation. When actually measuring soldering shapes, it is possible to set windows for multiple objects (for example, lead parts of electronic components) and measure the shapes of each at once.

By being able to measure multiple shapes at once in this way, the measurement speed can be increased.

Furthermore, in this example, the object of shape measurement was moved to the center of the camera (5), but since it is sufficient to perform relative positioning, it is also possible to use the camera (5) for positioning. good.

[Effects of the Invention] As described above, by using the shape measuring device using the method of the present invention, it has become possible to easily and quickly measure objects with surfaces or mirror surfaces, which have been difficult to measure with conventional measuring methods. Further, since the calibration method has been established, the measurement accuracy of the shape measuring device of the present invention and the shape measuring method used therein can be made sufficiently reliable.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams for explaining the principle of shape measurement of the present invention, and FIG. 4 is a configuration diagram of the first embodiment of the present invention.
5 to 7 are explanatory diagrams for explaining the action, FIG. 8 is a measurement diagram showing the shape detection results of the second embodiment, and FIGS. 9 and 10 are diagrams of the third embodiment. FIGS. 11 and 12 are configuration diagrams showing other embodiments of the device using the present invention, and FIGS. 13 to 15 are diagrams for explaining the prior art. Explanatory diagram, No. 16
17 and 17 are explanatory diagrams for explaining the operation of the third embodiment, FIG. 18 is an explanatory diagram for explaining the operation of the fourth embodiment, and FIG. 19 is also an explanatory diagram for explaining the operation of the fourth embodiment. An explanatory diagram for explaining the operation of the fifth embodiment, FIG. 20 is a configuration diagram showing the main configuration of the sixth embodiment, and FIGS. 21 and 22 are diagrams for explaining the operation of the sixth embodiment. FIGS. 23 and 24 are explanatory diagrams for explaining the operation of the seventh embodiment, and FIGS. 25 and 26 are explanatory diagrams for explaining the operation of the calibration method. Figure, No. 27
The figure is J for explaining the arrangement of the fourth embodiment. 1...Cover 2...LED

Claims (8)

[Claims] (1) A mounting table on which the object to be measured is placed at a predetermined position, and light is irradiated from multiple predetermined positions above the mounting table at a predetermined angle, respectively, to the object to be measured on the mounting table. a plurality of light sources, a light source control means capable of independently lighting any one or more of the plurality of light sources, and an image including the part to be measured illuminated by the light source from a predetermined position. A single or plural imaging means, a storage means for storing image data captured by the imaging means, and a command to turn on the single or plural light sources at a predetermined arbitrary position to the light source control means; arithmetic control means that captures image data from the imaging means in synchronization with the lighting of the image pickup means, stores it at a predetermined address of the storage means, and measures, recognizes or inspects the shape based on the stored single or plural image data; A shape measuring device characterized by comprising: (2) The shape measuring device according to claim 1, wherein the imaging means includes an optical system that changes the vertical and horizontal magnification ratio according to the object to be inspected. (3) Each of the multiple light sources has a known width of angular information, and the distance, size, and light reception level of the light sources are adjusted so that the width of this angular information partially overlaps with the width of angular information of other light sources. The shape measuring device according to claim 1, wherein the shape measuring device is set. (4) A mounting table on which the object to be measured is placed at a predetermined position, and light is irradiated from multiple predetermined positions above the mounting table at a predetermined angle, respectively, to the object to be measured on the mounting table. a plurality of light sources, a light source control means capable of independently lighting any one or more of the plurality of light sources, and an image including the part to be measured illuminated by the light source from a predetermined position. A single or plural imaging means, a storage means for storing image data captured by the imaging means, and a command to turn on the single or plural light sources at a predetermined arbitrary position to the light source control means; arithmetic control means that captures image data from the imaging means in synchronization with the lighting of the image pickup means, stores it at a predetermined address of the storage means, and measures, recognizes or inspects the shape based on the stored single or plural image data; In the shape measuring method used in the equipped shape measuring device, only one light source at an arbitrary position is turned on, and the light sources at other positions are turned off,
A single light source lighting step in which light sources at different positions are sequentially blinked in a predetermined order, and an imaging step in which images are sequentially taken by an imaging means in synchronization with the lighting of the single light source turned on in this single light source lighting step. , a storage step of sequentially storing the image data obtained in this imaging step in a storage means, and image data based on the relationship between the position of the light source and the position of the imaging device corresponding to each of the plurality of image data stored in this storage step. A shape measuring method comprising the step of determining the slope of an upper pixel and measuring the shape from the slope of the object to be measured corresponding to this pixel. (5) A mounting table on which the object to be measured is placed at a predetermined position, and light is irradiated from multiple predetermined positions above the mounting table at a predetermined angle, respectively, to the object to be measured on the mounting table. a plurality of light sources, a light source control means capable of independently lighting any one or more of the plurality of light sources, and an image including the part to be measured illuminated by the light source from a predetermined position. A single or plural imaging means, a storage means for storing image data captured by the imaging means, and a command to turn on the single or plural light sources at a predetermined arbitrary position to the light source control means; arithmetic control means that captures image data from the imaging means in synchronization with the lighting of the image pickup means, stores it at a predetermined address of the storage means, and measures, recognizes or inspects the shape based on the stored single or plural image data; In the shape measuring method used in the equipped shape measuring device, there is a light source lighting step in which light sources in a plurality of positions divided into predetermined blocks are sequentially turned on and light sources in other positions are turned off; An imaging step in which images are sequentially taken by an imaging means in synchronization with the lighting of a light source, a storage step in which image data obtained in this imaging step is sequentially stored in a storage means, and image data stored in this storage step. The bright points on the image corresponding to the light sources turned on in the lighting step are classified from the above, and the bright spots corresponding to the pixels on the image data are classified based on the relationship between the position of the light source and the position of the imaging device corresponding to each of the plurality of image data. 1. A shape measuring method comprising the steps of determining the inclination of an object to be measured and measuring the shape from the inclination of the object to be measured corresponding to this pixel. (6) A mounting table on which the object to be measured is placed at a predetermined position, and light is irradiated from multiple predetermined positions above the mounting table at a predetermined angle, respectively, to the object to be measured on the mounting table. a plurality of light sources, a light source control means capable of independently lighting any one or more of the plurality of light sources, and an image including the part to be measured illuminated by the light source from a predetermined position. A single or plural imaging means, a storage means for storing image data captured by the imaging means, and a command to turn on the single or plural light sources at a predetermined arbitrary position to the light source control means; arithmetic control means that captures image data from the imaging means in synchronization with the lighting of the image pickup means, stores it at a predetermined address of the storage means, and measures, recognizes or inspects the shape based on the stored single or plural image data; In a shape measuring method used in a shape measuring device equipped with a shape measuring device, a group in which the light source is divided in advance into a plurality of blocks, and a single or plural blocks of preset light sources are combined so that some of the blocks overlap each other. a group light source lighting step in which the group light sources are turned on in sequence, an imaging step in which images are sequentially taken by an imaging means in synchronization with the lighting of the single light source turned on in this group light source lighting step, and image data obtained in this imaging step. a storage step of sequentially storing the images in the storage means; and an image calculation step of calculating the plurality of image data stored in this storage step to extract image data when each block of the light source independently illuminates the object to be inspected. When each block obtained in this image calculation process independently illuminates the object to be measured, the bright points in the image data are classified as to which light source in the same block was illuminated, and multiple The inclination of the object to be measured corresponding to the pixel on the image data is determined from the relationship between the position of the light source and the position of the imaging device corresponding to each image data, and the shape of the object to be measured is determined from the inclination of the object to be measured corresponding to this pixel. A shape measuring method characterized by comprising a shape measuring step of measuring. (7) Claim 4 further comprising the step of determining the authenticity of the inclination of the object to be measured corresponding to the determined pixel in the shape measurement step by comparing it with pre-stored reference data.
7. The shape measuring method according to claim 6. (8) A mounting table on which the object to be measured is placed at a predetermined position, and light can be irradiated from multiple predetermined positions above the mounting table at a predetermined angle to the object to be measured on the mounting table. a plurality of light sources; a light source control means capable of independently lighting any one or more of the plurality of light sources; and a light source control means capable of independently lighting any one or more of the plurality of light sources; or a plurality of imaging means and a storage means for storing image data captured by the imaging means;
Issue a command to the light source control means to turn on one or more light sources at a predetermined arbitrary position, capture image data from the image pickup means in synchronization with the lighting of the light sources, and store it at a predetermined address of the storage means; In a method for calibrating a shape measuring device, which is equipped with arithmetic control means that measures, recognizes, or inspects the shape based on one or more stored image data, the shape of the object to be measured is known in advance and the surface is almost a mirror surface. The reference body is placed on the above-mentioned mounting table, the light source at any position of the light source is turned on, image data at this time is obtained by the imaging means, and the bright position of the image data at this time and the shape of the above-mentioned reference body to be measured are detected. A method for calibrating a shape measuring device, comprising calibrating a relationship between a light source position and an imaging position using data.