JPH05231837A - Method and device for measuring shape - Google Patents

Abstract

PURPOSE:To improve measurement accuracy by eliminating unneeded information from image information by subtracting image data due to reflection light from an object to be measured which is illuminated at each specified angle. CONSTITUTION:A lighting part 120 is provided with a plurality of LEDs 122... which are laid out regularly in the direction of latitude and that of longitude of a supporting member 121 in hollow semi-spherical shape which shields disturbance light. When an ITV camera 131 lights arbitrary LEDs..., an image of light which is irradiated onto a brilliance surface of an object 100 to be measured and is reflected upward vertically is picked up. An image-processing device 141 is provided with an amplification circuit 142, an A/D conversion circuit 143, an image memory 144, an operation circuit 145, etc. The memory 144 stores the image signal which is taken in by one lighting of an LED 122 as one image data and then stores it at a specified address in sequence. the operation circuit 145 reads two image data which are tentatively stored in the memory 144 and performs subtraction operation for eliminating an image which is common to both image data, namely an unneeded data.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the shape of a three-dimensional object, and more particularly to a method and apparatus for measuring the shape of a soldered portion of an electronic component bonded on a mounting board.

[0002]

2. Description of the Related Art The inspection of the mounting state of electronic parts has been mainly dependent on visual inspection, but in recent years, various inspection devices have been developed in order to eliminate such manual work and automate it.

For example, the shape measuring apparatus shown in FIG. 7 was previously developed by the present applicant (Japanese Patent Application No. 2-239909).
The mounting state of the electronic component is inspected by measuring the shape of the soldered portion. This shape measuring device
Stage part (710) for mounting the mounting board to be measured
An illumination unit that illuminates the mounted mounting board (100), an imaging unit that images reflected light from the irradiated mounting board (100), and the mounting substrate (100) based on the output from the imaging unit. Image processing device to measure the soldering condition of the above electronic components (74
1) and a control device (747) that controls the operation of the entire device. The configuration and operation of this device will be described below.

The stage section (710) is horizontally installed while holding the mounting substrate (100) to be measured, and can be moved in the in-plane direction by an XY table (not shown).

The illuminator is a hollow and hemispherical support member (72
1) and a plurality of LEDs (722) arranged regularly and inward in the longitude and latitude directions of the support member (721), with the opening facing the stage part (710). It is installed so that the mounting substrate on the mounting table can be illuminated by the light emitted from the LEDs (722).

The image pickup unit is, for example, an ITV (Industrial Telecommunications).
image sensor such as a camera (731), which is arranged in the central portion of the support member (721) and has an LED (72).
2) The reflected light from the soldering portion on the mounting board (100) irradiated by the above is imaged and an image signal is output. In FIG. 7, the ITV camera (731) images the stage part (710) vertically downward from the apex of the support member (721), but as shown in FIG. You may make it image with a camera. The image processing device (741) is adapted to perform arithmetic processing on the image signal output from the imaging section.

The control device (747) is electrically connected to each part and issues a displacement command to the XY table in the stage part (710) so that the measurement position of the mounting board (100) is the ITV camera (731). It is designed to be horizontally moved to the image pickup position. Further, each LED (722) is controlled to be lit, for example, the LEDs (722) arranged on the same latitude can be lit all at once and can be lit sequentially in the meridian direction for each latitude. It is like this. Further, the ITV camera (731) is adapted to image the reflected light and output an image signal in synchronization with the lighting of the LEDs (722). Next, the operation of this shape measuring apparatus will be described.

Upon receiving a command from the control device (747), the LE
D (722) ... is turned on and the mounting board (1
00) is irradiated. The surface of the soldered portion applied to the lead wire of the electronic component mounted on the mounting board (100) has gloss. Therefore, the irradiation light is specularly reflected by the surface of the soldering portion and goes upward, and is imaged by the ITV camera (731). Here, the LED (72
2) incident angle θ _i and the angle φ _{j at} which the j-th ITV camera (731) that receives the specularly reflected light looks down on the stage section (710).
And the inclination angle Θ _i of the specular reflection portion of the soldered portion are as shown in the following equation (1), as is clear from FIG. 4 (a). Θ _i = 90 °-(θ _i + φ _j ) / 2 (1)

Similarly, the incident angle θ _{i + 1} of the LED (722) arranged on the i + 1th latitude and the jth ITV camera (731) that receives the specularly reflected light are the stage section (710). )
The relationship between the angle φ _j looking down and the inclination angle Θ _{i + 1} of the specular reflection part of the soldered part is as shown in Fig. 4 (b).
(1) 'will be as shown. Θ _{i + 1} = 90 °-(θ _{i + 1} + φ _j ) / 2
(1) '

The bright spot in the image area taken by the ITV camera (731) is the regular reflection light of the LED (722),
The gradient in the bright part can be found from equation (1). Furthermore i
The +2, i + 3 ... th latitude LED (722) ... Is made to emit light one by _one , and the ITV camera (731) receives the specularly reflected light from each point in the soldering part where the gradient is Θ _{i + 1} , Θ _{i + 2} The image is picked up and the gradient at each point is obtained. Here, the mounting substrate (100) is set on the XY plane, the normal direction thereof is set on the Z axis, and the shape of the soldered portion is represented by the following expression (2). z = f (x, y) (2)

The height z of an arbitrary point (x, y) is obtained by integrating the gradient Θ (x, y) obtained by imaging specular reflection light, and the obtained point (x, y, z) is obtained. If tied, the shape of the soldered part can be measured.

It should be noted that if the array of LEDs (722) ... in the longitudinal direction is made dense, and the like, as shown in FIG.
(X, y) is a substantially continuous function, and equation (2) z = f (x, y) indicating the shape can be obtained by ordinary mathematical operation. However, for the sake of efficiency, the sampling of the gradient Θ is sparsely performed as shown in FIG. Therefore, taking into account that the solder maintains a smooth shape that solidifies from the molten state and changes continuously, an approximate expression is obtained from the sampling points Θ ₁ , Θ _2, ... Can be considered to have the same precision as Eq. (2).

It is preferable that the LEDs (722) ... Are sufficiently distant from the dimension of the object to be measured because the error of the incident angle θ on the measurement surface is reduced. However, even if they are not sufficiently separated, if the error is within the allowable range, it is possible to make a calculational correction based on the position and size of the light source and the distance to the measurement object.

Further, the closer the LEDs (722) are to the point light source, the ideally the gradient Θ of the reflecting surface can be obtained. However, the point light source is not practical in terms of manufacturing technology and cost, and the actual LED (722) has directivity and is spot light having a predetermined area. This L
Due to the directivity of ED (722) ..., the vicinity of the calculated gradient Θ is specularly reflected in addition to the portion. Here, if the error of the gradient Θ due to the spread of the incident light is set as α,
(1) is expressed by the following equation (3). Θ _i = 90 °-(θ _i + φ _j ) / 2 ± α (3)

This width α is influenced by not only the size of the light source itself but also the relative distance to the object to be measured, the sensitivity of the light receiving element of the ITV camera (731) and the binarization level. Also in this case α
If is within the allowable range, the correction can be made in the calculation. Less than,
The influence of α on the shape measurement will be considered with reference to FIG.

An ITV camera (73) in which a mounting substrate (100) is horizontally placed on a stage portion (710) and a soldering portion applied to a lead wire of the electronic component is installed vertically above the mounting portion (710).
The image was taken in 1), and the error width α is 5 °. First, when the LED (722) having a latitude of 30 ° is turned on, the portion A of the soldered portion shown in FIG. 10 is specularly reflected. A gradient Θ
₃₀ . Is Θ _{30 according} to equation (3). = 90 ° − (90 ° + 30 °) / 2 ± 5 ° = 30 ° ± 5 ° That is, 25 ° to 35 °. When the LED (722) with the latitude of 50 ° is turned on at the same longitude, the gradient Θ _{50 of} the specularly reflected portion B is Θ ₅₀ . Is the Θ ₅₀ . = 90 ° − (90 ° + 50 °) / 2 ± 5 ° = 20 ° ± 5 ° That is, 15 ° to 25 °. Furthermore, when the LED (722) with a latitude of 70 ° is turned on at the same longitude, the gradient Θ _{70 of} the specularly reflected portion C is ₇₀ . Is Θ ₇₀ . = 90 °-(90 ° + 70 °) / 2 ± 5 ° = 10 ° ± 5 °

That is, the angle is 5 ° to 15 °. And
Each of A, B, and C has an area, and adjacent ones partially overlap each other at AB and BC. These overlapping portions have two pieces of gradient information, and it can be estimated that AB has a gradient of 25 ° and BC has a gradient of 15 °. In this way, by using the size of the surface light source, the same effect as increasing the sampling points can be obtained.

The shape of the soldered portion is measured as described above.
Obtained by approximation calculation based on the sampled gradient Θ _i . This specific method will be described below with reference to FIGS.
It will be explained using 13.

Reference symbol S in FIG. 11 denotes a soldering portion applied to the lead wire Q, which is provided on the same meridian of the LED (7
22) The specular reflection portions A, B, C, ... When the lights are sequentially lit from the higher latitude are overlaid on the same drawing. Due to the wettability between the solder and the metal, the soldered part has an arch shape that extends along the protruding direction of the lead wire Q, and the slope becomes gentler as it approaches the tip of the lead wire Q. .. Here, each specular reflection portion A, B, C ...
The center of gravity is _{g 1, g 2, g 3} ... respectively, each theta ₁ gradient of each of the positive reflected portion obtained by the image processing described above, theta
₂ , Θ ₃ ... And the boundary between the solder S and the substrate at the tip of the lead Q is g ₀ . Here, between the adjacent centers of gravity g ₀
The midpoints of g ₁ , g ₁ g ₂ , g ₂ g _3, ... Are respectively C ₀ and C
₁ , C _2, ..., And the distances between C ₀ C ₁ , C ₁ C ₂ , C ₂ C ₃ ... Are respectively set as L ₁ , L ₂ , L ₃ . Then,
The solder surface heights z ₁ and z ₂ at the respective points C ₁ and C ₂ are calculated by the following equations (4) and (5), respectively. z ₁ = L ₁ × tan θ ₁ (4) z ₂ = L ₂ × tan θ ₂ + z ₁ (5) Therefore, by repeating similar approximation calculations,
Z _i at the solder surface C _i point is

[0020]

[Equation 1] Is derived. Point z obtained in this way
_{If 1} , z ₂ ... Are plotted on a three-dimensional screen and adjacent points are connected by a straight line, the cross-sectional outline of the soldered portion S is drawn as shown in FIG. In addition, L on another meridian
ED (722) ... is sequentially turned on for each longitude, and the height of each point is calculated in the same manner, and when these are plotted on the same coordinates,
As shown in FIG. 13, the three-dimensional shape of the soldered portion S can be drawn.

[0021]

However, on the mounting substrate, there are spots such as foreign matters, irregularities, residual flux, wiring patterns, etc., which have gloss in addition to the soldering portion.
The camera also images scattered and reflected light from these, which causes erroneous recognition.

Further, since the shape and size of the object to be measured are usually unknown, the ITV camera has been designed to image a large area with a margin. Therefore, the image data including a lot of unnecessary information is processed, which is not efficient.

Further, since the light source actually used is not a point light source but an LED having directivity, the specular reflection surface of the soldering portion has an area corresponding to the spread of the light beam. That is, since an unknown factor such as α shown in Equation (3) is included between the incident angle of light, the angle looked down by the ITV camera, and the tilt angle of the specular reflection surface, image processing is complicated. It was.

The LEDs are arranged in the latitudinal direction on the inner periphery of the support member on the hemisphere. Therefore, the circumference is shortened according to the latitude, the number of LEDs to be arranged is reduced, and uneven illumination occurs. Further, when a high-latitude LED is turned on, the ratio of illuminating the surface of the mounting substrate is increased, and the scattered reflected light that becomes noise is also increased.

Therefore, an object of the present invention is to provide a simple and highly reliable shape measuring method by reducing the influence of noise light and the influence of uneven illumination caused by lighting of LEDs for each latitude. [Constitution of Invention]

[0026]

The present invention has been made in consideration of the above-mentioned problem to be solved, and an illumination step of illuminating an object to be measured at a predetermined angle, and an object to be illuminated from the object to be measured. An imaging step of imaging reflected light and outputting an image signal; a first calculation step of subtracting the image data from each other to create first image data in which common image information is erased; and the first image A second calculation step of measuring the shape of the measurement object based on the data, which is a shape measuring method.

The present invention also includes an illuminating step of illuminating the measurement object at a predetermined angle, and an imaging step of imaging reflected light from the illuminated measurement object and outputting an image signal.
A first calculation step of creating first image data by subtracting image data from each other to delete common image information; and a first calculation step of subtracting the first image data from each other to delete common image information. A shape measuring method comprising: a second calculating step of creating image data of No. 2; and a third calculating step of measuring the shape of a measuring object based on the second image data. ..

Further, according to the present invention, a mounting table on which the measuring object is placed, an illuminating section which illuminates the measuring object from a plurality of angles, and a picked-up image of the illuminated measuring object. An image capturing unit that outputs data, a storage unit that stores image data, a subtraction unit that subtracts captured image data from each other to delete common image information, and an arithmetic processing of the image data to calculate the shape of the measurement target. The shape measuring apparatus is provided with:

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of the shape measuring apparatus according to the present embodiment.

This shape measuring apparatus includes a stage section on which the mounting board (100) is mounted, an illumination section (120) for illuminating a measurement area on the mounted mounting board (100), and reflection from the measurement area. An image pickup unit that picks up light and outputs an image signal S1 and an arithmetic control unit (140) that processes the input image signal S1 and controls the operation of the entire apparatus are provided.

The stage part includes a mounting table (111) for mounting the mounting substrate (100) at a predetermined position by vacuum suction or the like, and an XY for driving and displacing the mounting table (111) in the in-plane directions (XY directions). The board (100) with the table (112)
The optional soldering part (101) above can be positioned at a predetermined position.

The illuminating part (120) has a hollow hemispherical support member (121) for blocking ambient light, and 10 in the longitudinal direction of the support member (121).
And a plurality of LEDs (122) arranged regularly inward of the hemisphere every 5 ° in the latitudinal direction and 5 ° in the latitudinal direction, and the opening of the support member (121) has the above-mentioned stage part (110).
It is supported and fixed by a pillar (150) so as to face with.
Each LED (122) is installed so that its optical axis faces the center of the hemisphere formed by the support member (121), and each lighting is controlled by the arithmetic control unit (140), for example, on the same latitude. One row of LEDs (122) ... Can be sequentially turned on in the meridian direction. Further, the height (Z position) of the illumination unit (120) from the mounting table (111) can be freely adjusted by the column (150). It should be noted that the light source may be any light source having a small directivity and little color unevenness,
It is not limited to LEDs. Also, 1 in the longitude direction
The LED array interval of 0 ° and 5 ° in the latitude direction is for convenience of description, and is not limited to this.

The image pickup section is composed of, for example, an ITV camera (131) or the like, and is adapted to output an image signal S1 corresponding to the brightness of the picked-up image. In FIG. 1, the ITV camera (1
The support 31 (31) is supported and fixed by a support (150) so that the inside of the support 31 (121) can be imaged vertically downward through a transmission hole or at the top. That is, the ITV camera (1
When an arbitrary LED (122) ... Is turned on, the reference numeral 31) images the light that is specularly reflected vertically upward when the glossy surface such as the soldering portion 101 is illuminated. Also IT
A magnifying lens system (not shown) is arranged in front of the image pickup surface of the V camera (131) so that the image pickup area can be arbitrarily zoomed up. The image pickup unit is not necessarily mounted on the mounting board (100) from the top of the support member (121).
The present invention is not limited to the above-described image capturing method, but a transparent hole may be provided at an arbitrary position on the spherical surface formed by the support member (121) and the image may be captured from there. Also, in order to eliminate blind spots in the imaging range,
Images may be captured from a plurality of positions as shown in FIG. Further, although the position of the LED and the transmission hole of the ITV camera are different from each other in FIG. 1, a half mirror may be used to provide the epi-illumination type. In addition, the LED (122) is attached to the support member (1
21) Instead of fixing the LED (12) by rotating the support member as shown in Japanese Patent Application No. 4-101252.
2) may be moved.

The arithmetic control section (140) is electrically connected to each section, and an image processing apparatus (141) for image-processing the image signal S1 input from the image pickup section and a control apparatus for controlling the operation of each section. (147) and

The image processing device (141) performs an analog-digital conversion (hereinafter referred to as A / D conversion) on the amplifier circuit (142) for amplifying the input image signal S1 and the amplified image signal S2. An A / D conversion circuit (143) for outputting the digital image signal S3, an image memory (144) for temporarily storing the digital image signal S3 as image data, an operation circuit (145) for comparing and operating the image data, and an operation Measuring circuit (14) that measures the shape of the object to be measured according to the output from the circuit (145).
6) and are provided.

The image memory (144) has one LED (122)
The image signal taken in by turning on the ... Is sequentially stored at a predetermined address as one image data. Then, these image data are (a) of FIG.
As shown in (b) and (c), the image information has gradations according to the brightness of the captured image area.

The arithmetic circuit (145) reads out the two image data temporarily stored in the image memory (144) and subtracts them to erase the image common to both image data or add them. Both image data can be processed and combined. For example, in FIG.
The image data obtained by subtracting the figure (a) from the figure (b) is the same figure.
(b '). Similarly, the image data obtained by subtracting the figure (a) from the figure (c) becomes the figure (c'). Also, with the same figure (b ')
The image data obtained by adding (c ') and (c') is as shown in (d). The image data shown in FIG. 2 (d) is image information obtained by sequentially turning on each row of LEDs (122) ... Lined up on the same latitude, and the shape and dimensions of the pattern indicate the shape of the measurement object. It has been reflected. The measurement circuit (146) is configured to calculate the shape of the measurement object based on one or more image data obtained by the subtraction / addition processing.

The control device (147) includes a lighting control circuit (148) for controlling blinking of the LEDs (122), and an XY table drive control circuit (149) for controlling drive displacement of an XY table built in the stage section. ) And.

The lighting control circuit (148) can determine the lighting order of the LEDs (122) ... Which are regularly arranged on the support member (121), for example, the LEDs () arranged on the same latitude. 1
22) ... can be turned on all at once, and can be turned on and off sequentially for each latitude.

The XY drive control circuit (149) is an XY table.
The mounting board (100) placed by the (112) can be moved in the in-plane direction, and the soldering part to be measured can be displaced so as to be located at the center within the imaging area of the ITV camera (131). You can do it.

The control device (147) is also electrically connected to the magnifying lens system of the image pickup section, and can issue a zoom-up command to the magnifying lens system to set the size of the image pickup area of the ITV camera (131). It is like this.

In the present embodiment, the arithmetic control unit (1
40) is a display section (1
61) and an input section (162) such as a console,
An image taken by the ITV camera (131) can be displayed, the shape measurement result can be output, and instructions can be given from the outside. Next, a shape measuring method using this shape measuring apparatus will be described.

First, the mounting substrate (100) is mounted on the stage section (110).
The support member (121) is placed at a predetermined XY position so that the equatorial plane of the support member (121) substantially coincides with the surface of the mounting substrate (100).
Adjust the height of 1).

The XY drive control circuit (149) issues a drive control signal so that the soldering portion to be measured is located at the center of the imaging area based on the information of the mounting position of the mounting board (100). Drive (112). Lighting control circuit (14
8) issues a lighting control signal so that the LEDs (122) arranged in a line on the same latitude are sequentially lit from a joke.

However, specular reflection light from the soldering portion and scattered reflection light from the wiring pattern etc. are incident on the ITV camera (131). In Figure 2, the LEDs (122) lined up in a row
The captured image when is turned on for each latitude is shown. In other words, (a), (b), and (c) in the figure are latitudes 85 ° and 80 °, respectively.
And the LEDs (122) lined up above and 75 ° are simultaneously turned on for each row. ITV camera (13
1) is an image signal S1 according to the brightness of which the reflected light is imaged in synchronization with the lighting of the LEDs (122) ...
Is output. The amplifier circuit (142) inputs the image signal S1 and amplifies it, and the A / D conversion circuit (143) inputs the amplified image signal S2 and outputs a digital image signal S3.

The image memory (144) includes LEDs (122) in each column.
Each digital image signal S3 taken in by turning on is stored and held as image data at a predetermined address. For example, each image data G ₈₅ obtained by turning on the LEDs (122) ... At latitudes of 85 °, 80 ° and 30 ° simultaneously for each column. , G
₈₀ . , G ₃₀ . Are patterns similar to those in FIGS. 2 (a), 2 (b) and 2 (c), respectively.

Here, the LEs lined up at the uppermost latitude of 85 °
Consider a case where D (122) ... Are simultaneously lit. The proper shape of the soldered portion is an arch shape as shown in FIGS. 8 and 9, and the inclination angle is gradually reduced toward the tip of the lead. From the surface, φ from above
A tilt angle Θ ₈₅ that satisfies the formula (1) between the ITV camera (131) looking down at 90 °. It is easily inferred that the part that becomes is extremely narrow. Therefore, in this case, the ITV camera (131) receives almost no specular reflection light from the soldering part (101), and scatters reflection light from foreign matter, residual flux, wiring patterns, etc. on the surface of the mounting board (100). May be imaged. Therefore, the image data G ₈₅ shown in FIG. The bright portion Na in the inside is due to these scattered reflected light. In addition, when the LEDs (122) that are lined up at a latitude of 80 ° are turned on all at once, the formula (1) on the surface of the soldered part is used.
Inclination angle Θ ₈₀ to meet. The part near ＝ 5 ° forms a strip along the latitudinal direction and is specularly reflected, and the mounting board (100)
The surface also reflects irregularly. Therefore, the image data G ₈₀ shown in FIG. Consists of a bright portion B due to specularly reflected light and a bright portion Nb due to scattered reflected light. Image data G ₃₀ shown in FIG. … Also the bright part C due to the specular reflection light from the soldered part
, And a bright portion Nc due to scattered reflection light from the surface of the mounting substrate (100).

The arithmetic circuit (145) first outputs the image data G ₈₅ from the image memory (144). And G ₈₀ . Read out. G ₈₅ . And G ₈₀ . As described above, the images include images Na and Nb by the scattered light from the surface of the mounting substrate 100, respectively. These Na and Nb are images common to both image data and are unnecessary information unrelated to the shape of the soldered portion. Therefore, in the arithmetic circuit (145), G ₈₀ .
-G _85. By subtracting the common image contained in both image data,
The unnecessary information b is removed, and the image data shown in FIG. 2B 'is created. Next, the arithmetic circuit (145) is connected to the image memory (1
44) to image data G ₃₀ . And read G ₃₀ . −
G ₈₅ . The subtraction process is performed to create image data from which unnecessary information is removed as shown in FIG. Further, the arithmetic circuit (145) sequentially outputs the image data G ₂₀ . , G ₁₀ . Similarly, the subtraction process is performed on the image data G ₂₀ to remove unnecessary information. -G _85. , G ₁₀ . -G _85. Create ... Further, due to the resolution of the ITV camera (131), the distortion of the image signal, and the directivity of the LEDs (122), an overlapping portion may occur between the specular reflection surfaces of the LEDs (122) on each latitude. In this case, for example, G ₈₀ . -G _85. And G ₃₀ . -G _85. , G ₃₀ . -G _85. And G ₂₀ . -G _85. The adjacent image data are subtracted from each other as shown in FIG.
Sharpen the outline of.

Next, the arithmetic circuit (145) outputs each image data G ₈₀ obtained by the above-mentioned procedure. -G _85. , G ₃₀ . −
G ₈₅ . , G ₂₀ . -G ₈₀ . Is added to create image data ΣG by superimposing these on the same image area. For example, image data G ₈₀ . -G _85. And G ₃₀ . −
G ₈₅ . When the addition processing is performed only for
It becomes like (d). This ΣG pattern reflects the shape of the soldered portion. That is, it is possible to know the unevenness of the surface and its gradualness by the area, shape, and interval of the bright portions B, C ... In ΣG. The measurement circuit (146) measures the shape of the soldered portion and determines the shape defect based on ΣG by the same procedure as the above-mentioned conventional technique.

Consider a case where the normal soldering portion has an arch shape in which the inclination becomes gentler toward the tip of the lead. It can be easily inferred from the formula (1) that the pattern of the bright part of the image data obtained by irradiating the row of LEDs at high latitude should be closer to the tip side of the lead wire than that of the LED at low latitude. Therefore, the measuring circuit (146) is G ₈₀ . −
G ₈₅ . Is G ₃₀ . -G _85. Is closer to the tip of the lead than the LE, that is, the LE of the bright pattern in ΣG is lit.
By determining whether or not they are aligned according to the latitude order of D (122) ..., it is possible to easily obtain a defect in soldering by obtaining information regarding the unevenness of the shape of the soldering portion.

Further, in ΣG, only the soldered portion to be measured appears as a bright portion. Therefore, the control device (1
47) sets a portion Z surrounded by a broken line in FIG. 2D as an inspection area, and gives a command to the magnifying lens system of the image pickup unit (130) so as to zoom up the image pickup area to the size of Z in ΣG. Emit. However, most of the pixels of the ITV camera (131) are used for imaging the soldered portion and the inspection target can be efficiently extracted, and the amount of unnecessary information in the image data is reduced.
Measurement accuracy is improved.

Next, another shape measuring method using this shape measuring apparatus will be described with reference to FIGS. 5 and 6. For the sake of convenience, a spherical body forming a mirror surface will be described as an object to be measured, but the LEDs (12
2) ... are turned on sequentially and the reflected light is reflected by the ITV camera (131)
Since the point of capturing an image is the same as described above, the description will be omitted.

High latitude, ie 80. And 70. When the LEDs aligned above are turned on, the inclination is Θ _{80 according} to equation (1). = 5 ° ± α and Θ ₇₀ . = 10 ° ±
The specularly reflected light of the α portion enters the ITV camera (131).
When the image of the reflected light taken by the ITV camera (131) is viewed from the side, each G ₈₀ is shown by the shaded area in FIG. , G ₇₀ . become that way. As mentioned above, LEDs arranged at high latitudes
The unevenness of the illumination occurs due to the small number of pixels, and as a result, the edge of each reflection area becomes unclear. Also, due to the directivity of the LED, it is G ₈₀ as shown in FIG. And G ₇₀ . Has an overlapping portion B. Also, when irradiated from a high-latitude LED, the part of the spherical surface with a gentle inclination is easily reflected,
Noise Q is generated.

First, the arithmetic circuit (145) performs a subtraction process G ₇₀ .
-G ₈₀ . I do. Since the signal level on the image data takes only positive values, G ₇₀ . G ₈₀ out of the light section. All the portions overlapping with are erased, and the reflection area A by only turning on the LED at the latitude of 70 ° is extracted. Next, a subtraction process G ₇₀ . It performs a -A, G _70. And G ₈₀ . Only the overlapping portion B with and is extracted. Further, as shown in FIG. 6, the signal value on the image data B is projected in the X direction and the Y direction to obtain the peripheral distribution of the bright portion in each axial direction. Here, an arbitrary threshold value V _T is set and binarization processing is performed in each direction. Then B
The contours in both XY directions are clarified, and the inclination angle is Θ ₈₀ . = 5 °
The noise Q of the image of ± α can be deleted, and the tip of the reflection area can be detected. As a result, a target pattern can be extracted and the shape of the measurement object can be accurately measured without being affected by uneven illumination or noise. The shape can be measured by the same action even when the measurement object is not a spherical body but a soldered portion of an electronic component.

In the description of the operation of this embodiment, only one soldering portion to be measured is described, but this is for simplification of the description. When actually measuring the soldering status of electronic components, it is possible to set windows for multiple lead parts on the screen and measure each shape at once, and the navigation processing It is possible. Further, the present invention is not limited to the above-mentioned embodiments, and can be modified within the scope of the invention.

[0056]

As described above in detail, according to the present invention, I
Unnecessary information can be effectively removed from the image information captured by the TV camera, and the measurement target can be efficiently extracted. As a result, the measurement accuracy can be dramatically improved and a great industrial effect can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a shape measuring apparatus according to an embodiment of the present invention.

FIG. 2 is captured image data (an image pickup area taken by an ITV camera when an LED is turned on for each latitude),
It is a figure which shows the image processing of each image data.

FIG. 3 is a diagram showing a modified example of the shape measuring apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram showing a basic principle of a shape measuring method.

FIG. 5 is a diagram showing a shape measuring method according to an embodiment of the present invention.

FIG. 6 is a diagram showing a shape measuring method according to an embodiment of the present invention.

FIG. 7 is a diagram showing a conventional shape measuring apparatus.

FIG. 8 is a diagram showing a conventional shape measuring method.

FIG. 9 is a diagram showing a conventional shape measuring method.

FIG. 10 is a diagram showing a conventional shape measuring method.

FIG. 11 is a diagram showing a conventional shape measuring method.

FIG. 12 is a diagram showing a conventional shape measuring method.

FIG. 13 is a diagram showing a conventional shape measuring method.

[Explanation of symbols]

100 ... Mounting board, 110 ... Stage part, 121 ... Support member, 122 ... LED, 131 ... ITV camera, 140
... arithmetic control unit, 150 ... prop.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Fukudome 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture

Claims (3)

[Claims] 1. An illumination process of illuminating a measurement target object at a predetermined angle, an imaging process of capturing reflected light from the illuminated measurement target object and outputting an image signal, and subtraction processing of image data from each other. A first calculation step of creating first image data in which common image information is erased, and a second calculation step of measuring the shape of the measurement object based on the first image data. A shape measuring method characterized by. 2. An illumination step of illuminating a measurement object at a predetermined angle, an imaging step of imaging reflected light from the illuminated measurement object and outputting an image signal, and subtracting the image data from each other. A first calculation step of creating first image data in which common image information is erased, and second image data in which common image information is erased by subtracting the first image data from each other. The second calculation step, and the second
And a third operation step of measuring the shape of the measuring object based on the image data of 1. 3. A mounting table on which a measurement target is mounted, an illuminating unit that illuminates the measurement target from a plurality of angles, an image of the illuminated measurement target is captured, and captured image data is output. An imaging unit, a storage unit that stores image data, a subtraction unit that subtracts the captured image data from each other to delete common image information, and an arithmetic unit that arithmetically processes the image data to calculate the shape of the measurement target. A shape measuring device comprising: