KR100955272B1 - Apparatus for measurement of surface profile - Google Patents

Abstract

The present invention relates to a surface shape measuring apparatus for picking up a 2D image of a surface of a measurement object. A surface shape measuring apparatus according to the present invention includes: a first light source for irradiating a surface of a measurement object with first monochromatic light; A second light source for irradiating a surface of the measurement object with second monochromatic light of a color different from the first monochromatic light; A monochrome camera for picking up the first monochromatic light and the second monochromatic light emitted from the first light source and the second light source and reflected from the surface of the measurement object; Color image data and second monochrome image data corresponding to the first monochromatic light and the second monochromatic light, respectively, in a state in which the first monochromatic light and the second monochromatic light are respectively irradiated to the surface of the measurement object, 1 image data, the first light source, the second light source, and the monochrome camera, and calculates third monochrome image data based on the first monochrome image data and the second monochrome image data, And a control unit for processing the monochrome image data and the third monochrome image data into R, G, B data for corresponding pixels to generate a composite color image for the surface of the measurement object, And blue light, and the second monochromatic light is red light. As a result, a color 2D image can be obtained using a low-cost black-and-white camera, and a black-and-white camera having a higher processing speed than a color camera can be used.

Description

[0001] APPARATUS FOR MEASUREMENT OF SURFACE PROFILE [0002]

The present invention relates to a surface shape measuring apparatus, and more particularly, to a surface shape measuring apparatus capable of generating a composite color image using monochrome image data obtained from a monochrome camera.

BACKGROUND ART [0002] Recently, as the demand for electronic products has increased due to the spread of computers, mobile phones, PDAs, and the like, a printed circuit board (PCB) using surface mount technology (SMT) , &Quot; PCB ") are increasing in importance.

Among the equipment constituting the SMT inline system, a surface shape measuring device capable of photographing the surface shape of a PCB substrate is used as the inspection equipment. Such a surface shape measuring device is used in the manufacture of a PCB substrate such as an abnormality of parts mounting, poor soldering, And is used to detect an abnormality that occurs.

A surface profile measuring device, which is placed on the SMT inline system and captures the surface shape of the PCB substrate, is classified into a format using an area-scan camera and a format using a line-scan camera , And a case where an area-scan camera is generally used is more widely used.

1, a color filter (Bayer filter) is mounted on each pixel. A color filter such as a red filter or a green filter or a blue filter is attached to each pixel of the color camera. Are arranged so as not to be adjacent to each other.

Here, in order to create a color image using a color camera, all three color information R, G, and B are required for all pixels, but in a real color camera, one pixel has only R or G or B information. Therefore, as shown in FIG. 2, two different color information other than the inherent color information directly obtained is obtained through interpolation from the color information of the adjacent pixels. FIG. 2 shows an example of such interpolation. Such a color camera is also applied to a moire system which is a surface shape measuring device for acquiring a 3D image.

Generally, 3D measurement using a moire pattern is performed by projecting a grating onto a measurement object and then moving a grating at regular intervals three or more times to acquire an image to detect a change in brightness of a point to be measured . Therefore, one of the key points of 3D measurement using moiré pattern is how to accurately detect the change in brightness of the point or pixel to be measured.

Generally, it is difficult to use monochromatic light as a light source of a grid illumination in a 3D soldering inspection using a moire pattern. For example, when using a blue light source and measuring the surface of a red PCB, the PCB surface only reflects red light, so the camera can not detect light reflected from the PCB surface and can detect changes in brightness none. Therefore, it is impossible to make 3D measurement of the PCB with the red color of the surface with the blue illumination.

Therefore, in the Moire 3D surface shape measuring apparatus using a color filter, white light is used as a light source for lattice illumination. Even if white light is used, since only one of Red, Green or Blue can be taken for each pixel, 66.66 % Of pixels can detect only Green or Blue, so that the result of 3D measurement becomes unreliable.

On the other hand, as in the 3D measurement as described above, the necessity of the color image in the 2D measurement can be more important. In the case of 2D measurement using 2D / 3D compound inspection equipment, color image information is also very important.

In the case of solder inspection equipment using 2D method, color image using side lighting or top lighting is very important for accurate identification of lead solder. However, the color of the PCB surface is very diverse, and there are many cases where there is even a contrasting color in a PCB. Therefore, a color image with a quantity of information three times larger than that of a monochrome image is very effective for extracting a solder with only a 2D image.

In the NG inspection, the 2D image and the 3D image are mostly seen by the examiner and the final NG is determined. In the case of the black and white 2D image, there are many cases where the boundary between the solder and the pad is ambiguous. It is important that the inspector can draw clear conclusions.

Despite the importance of the color image in the surface shape measurement using the 2D image as described above, the color camera has a disadvantage that its cost is higher than that of the monochrome camera and the shooting speed is lower than that of the monochrome camera at the same resolution.

Therefore, a black-and-white camera is widely used in a 2D or 3D type surface shape measuring apparatus. Further, in the case of a 3D device using a moire pattern, a black and white camera is often used in that a color camera has a disadvantage, that is, reliability of a 3D measurement result is low even when white light is used as described above.

In the case of 3D equipment using moiré patterns, it is provided in the form of a composite inspection unit capable of 2D measurement. In order to increase the reliability of 3D measurement and lower the manufacturing cost, a monochrome camera is installed. When the boundaries between the solder and the pad are ambiguous, the effectiveness of the 2D measurement becomes small and the effectiveness as a 2D / 3D hybrid inspection apparatus becomes small.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a surface shape measuring apparatus capable of generating a composite color image using monochrome image data obtained from a monochrome camera.

According to the present invention, there is provided a surface shape measuring apparatus for picking up a 2D image of a surface of a measurement object, comprising: a first light source for irradiating a surface of the measurement object with first monochromatic light; A second light source for irradiating a surface of the measurement object with second monochromatic light of a color different from the first monochromatic light; A monochrome camera for picking up the first monochromatic light and the second monochromatic light emitted from the first light source and the second light source and reflected from the surface of the measurement object; Color image data and second monochrome image data corresponding to the first monochromatic light and the second monochromatic light, respectively, in a state in which the first monochromatic light and the second monochromatic light are respectively irradiated to the surface of the measurement object, 1 image data, the first light source, the second light source, and the monochrome camera, and calculates third monochrome image data based on the first monochrome image data and the second monochrome image data, And a controller for processing the monochrome image data and the third monochrome image data into R, G, and B data for the corresponding pixels to generate a composite color image for the surface of the measurement object, ≪ / RTI >

Here, the first monochromatic light may include any one of green light and blue light; The second monochromatic light may include red light.

Here, the control unit equation ^{I_3rd_data = n × (I_1st_data) k} + m × (I_2nd_data) p ( where I_1st_data is the first black-and-white image data, I_2nd_data is the second black-and-white image data, I_3rd_data is the third black-and-white Image data, n and k are constants given to the first monochrome image data to produce the third monochrome image data, and m and p are constants given to the second monochrome image data to produce the third monochrome image data. And the third monochrome image data can be calculated by the second monochrome image data.

According to the present invention, there is provided a surface shape measuring apparatus capable of generating a composite color image using monochrome image data obtained from a monochrome camera. This makes it possible to acquire a color 2D image using a low cost black and white camera, and to improve the processing speed by using a black and white camera having a higher processing speed than a color camera.

In addition, when applied to a 2D and 3D inspection apparatus using a moire pattern, it is possible to acquire a color image in a 2D measurement while using a monochrome camera, and the utility value of the 2D and 3D inspection apparatuses can be further improved.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram showing an example of the configuration of the surface shape measuring apparatus according to the first embodiment of the present invention. The surface shape measuring apparatus according to the first embodiment of the present invention is applied to a 2D measuring apparatus.

3, the surface shape measuring apparatus according to the present invention includes a first light source 31, a second light source 32, a monochrome camera 10, and a control unit 40.

The first light source 31 irradiates the first monochromatic light onto the surface of the measurement object 100 and the second light source 32 measures the second monochromatic light of a different color from the first monochromatic light irradiated by the first light source 31 The surface of the object 100 is irradiated. Here, the first monochromatic light irradiated from the first light source 31 of the surface shape measuring apparatus according to the present invention is green light or blue light, and the second monochromatic light irradiated by the second light source 32 is red light. For example.

The first light source 31 and the second light source 32 are provided in the form of a top illumination TL and / or a side illumination SL. In FIG. 3, the first light source 31 and the second light source 32 are applied to both the top illumination TL and the side illumination SL. That is, in the present invention, the first light source 31 and the second light source 32 are respectively provided on the side of the top illumination TL and the first light source 31 and the second light source 32 are disposed on the side illumination SL, As shown in Fig. Thus, the top illumination TL and the side illumination SL can be appropriately used, or both the top illumination TL and the side illumination SL can be used, depending on the shape of the measurement object 100. [

Here, the first light source 31 and the second light source 32 according to the present invention are provided in the form of LEDs (Light Emitting Diodes) that blink according to the control of the controller 40, And is turned on in synchronization with the imaging of the monochrome camera 10 in accordance with the control.

The monochrome camera 10 picks up the first monochromatic light and the second monochromatic light reflected from the surface of the measurement object 100 irradiated from the first light source 31 and the second light source 32. Then, the monochrome camera 10 transmits the monochrome image data photographed with respect to the first monochromatic light and the second monochromatic light to the control unit 40.

Hereinafter, the black-and-white image data acquired by the black-and-white camera 10 in the state in which the first monochromatic light is irradiated from the first light source 31 is referred to as first monochrome image data, the second monochromatic image data is obtained from the second light source 32, The black-and-white image data captured and obtained by the black-and-white camera 10 is defined as the second black-and-white image data.

The control unit 40 controls the first light source 31 and the monochrome camera 10 so that the first monochromatic light corresponding to the first monochromatic light is acquired while the first monochromatic light is irradiated to the surface of the measurement object 100 . The controller 40 controls the second light source 32 and the monochrome camera 10 so that the second monochromatic light corresponding to the second monochromatic light is acquired while the second monochromatic light is irradiated on the surface of the measurement object 100 .

Here, the monochrome camera 10 according to the present invention may be provided in the form of an area-scan camera or a line-scan camera. When the black-and-white camera 10 is provided in the form of an area-scan camera, the controller 40 receives the first monochromatic light from the first light source 31 when capturing one FOV (field of view) Acquires the first monochrome image data in the irradiated state and acquires the second monochrome image data in the state in which the second monochromatic light is irradiated from the second light source 32 for the same FOV (Field Of View). The control unit 40 also acquires the first monochrome image data and the second monochrome image data in the same manner for the next FOV (Field Of View) And second monochrome image data.

When the black-and-white camera 10 according to the present invention is provided in the form of a line-scan camera, the control unit 40 converts the first black-and-white image data and the second black- The first monochrome image data and the second monochrome image data for the entire surface of the measurement object 100 can be obtained.

When the first and second monochrome image data and the second monochrome image data are acquired in the same manner as described above, the controller 40 controls the synthesized color of the surface of the measurement object 100 using the first monochrome image data and the second monochrome image data, Create an image.

Hereinafter, a method for the controller 40 to generate a composite color image will be described, taking as an example that the first monochromatic light is blue light and the second monochromatic light is red light.

The first monochrome image data is data captured by the monochrome camera 10 while the blue light is irradiated on the surface of the measurement object 100 and the second monochrome image data is the data obtained when the red light is irradiated onto the surface of the measurement object 100 Is the data captured by the black-and-white camera 10 in a state in which the black-

At this time, the control unit 40 recognizes the first monochrome image data as Blue data among the R, G, B data for the generation of the synthesized color image, and converts the second monochrome image data into Red data for generation of the composite color image .

Then, the control unit 40 calculates Green data, which is the third monochrome image data, based on the first monochrome image data and the second monochrome image data. Here, an example of a method of calculating the third monochrome image data is as shown in the following equation (1).

[Equation 1]

I_3rd_data = n (I_1st_data) ^k + m (I_2nd_data) ^p

Here, I_1st_data is the first monochrome image data, I_2nd_data is the second monochrome image data, I_3rd_data is the third monochrome image data, and n and k are the first monochrome image data to produce the third monochrome image data And m and p are constants given to the second monochrome image data to produce the third monochrome image data. Here, the above equation (1) is an empirical formula determined through several experiments for the calculation of the third monochrome image data, and the constants n, k, m and p are also determined through experiments Is a constant. Therefore, [Equation 1] and constants n, k, m, and p may be variable depending on the kind of the measurement object and the measurement condition.

When the third monochrome image data is calculated for all the pixels in the above manner, the controller 40 synthesizes the first monochrome image data, the second monochrome image data, and the third monochrome image data to generate a composite color image, At this time, the control unit 40 processes the first monochrome image data, the second monochrome image data, and the third monochrome image data into R, G, and B data for mutually corresponding pixels, thereby generating a composite color image.

FIG. 4 and FIG. 5 are views illustrating an example of generating a composite color image using the first and second monochrome image data and the second monochrome image data using the surface shape measuring apparatus according to the present invention.

4 (a) shows the first black-and-white image data captured and obtained by the black-and-white camera 10 in a state where the first monochromatic light is irradiated with the first monochromatic light from the first light source 31, 4B shows the second black-and-white image data captured and acquired by the black-and-white camera 10 in a state in which the second monochromatic light is irradiated with the second monochromatic light in the second light source 32, .

As shown in Figs. 4 (a) and 4 (b), the first monochromatic light and the second monochromatic light are irradiated, respectively, and the image is captured using the monochromatic camera 10 to generate first monochromatic image data and second monochromatic image data The first monochrome image data and the second monochrome image data have only information on the brightness, not the information on the color.

Here, the controller 40 calculates the third monochrome image data using the first monochrome image data and the second monochrome image data as in Equation (1), and converts the three monochrome image data into R, G, and B data and synthesized, a composite color image is generated as shown in FIG.

As shown in FIGS. 4 and 5, the black-and-white image obtained by the irradiation of the blue light or the red light is not clearly distinguished from the solder and the pad, but it is understood that the distinction between the solder and the pad becomes clear when the composite color image is generated .

With the above-described configuration, by generating the composite color image using the monochrome image data obtained through the monochrome camera 10, it is possible to acquire the color image while installing the low-cost monochrome camera 10, By using the black-and-white camera 10 having a high processing speed, the processing speed can also be improved.

6 is a diagram showing a configuration of a surface shape measuring apparatus according to a second embodiment of the present invention. In the second embodiment of the present invention, the surface shape measuring apparatus is applied to a moire system which is a 2D / 3D measuring apparatus.

6, the surface shape measuring apparatus according to the second embodiment of the present invention includes a 3D light source unit 50, a monochrome camera 10, a first light source 31, a second light source 32, 40).

The 3D light source unit 50 irradiates light onto the surface of the measurement object 100 in 3D measurement. Here, the 3D light source unit 50 according to the present invention is arranged such that the 3D light source unit 50 is disposed at a predetermined distance from a reference plane (not shown, ideally, the surface of the PCB substrate when the measurement object 100 is a PCB substrate) on which the measurement object 100 is placed And a projection grating 52 disposed between the measurement object 100 and the light source and engraved with a lattice pattern.

As the 3D light source 51, it is preferable to use a light source that emits white light, and a laser diode, a halogen light source, and an LED light source, which are small and light in weight and relatively inexpensive in price, may be used. A projection lens 53 for projecting the light passing through the projection grating 52 onto the measurement object 100 may be disposed between the projection grating 52 and the measurement object 100 in the vicinity of the projection grating 52 have.

A grid pattern is formed in the projection grating 52. The light emitted from the 3D light source 51 is converted into lattice pattern light while passing through the projection grating 52. The lattice pattern light is reflected from the surface of the measurement object 100 to have a moire pattern, Dimensional information of the surface of the substrate 100 can be obtained.

Here, the projection grating 52 is finely moved in the transverse direction with respect to the transmission direction of light by a grating moving part (not shown). This enables the phase shift of the lattice pattern formed on the projection grating 52 and allows the moire pattern reflected from the surface of the measurement object 100 passing through the projection grating 52 and picked up through the monochrome camera 10 The control unit 40 obtains the 3D information on the surface shape of the measurement object 100. FIG.

On the other hand, the case of acquiring the 2D image through the surface shape measuring apparatus shown in Fig. 6 corresponds to the first embodiment described above. That is, when the first monochromatic light from the first light source 31 is irradiated on the surface of the measurement object 100, the controller 40 controls the first light source 31 And the monochrome camera 10 are controlled. The controller 40 controls the second light source 32 so that the second monochromatic light corresponding to the second monochromatic light is acquired while the second monochromatic light from the second light source 32 is irradiated on the surface of the measurement object 100 And the monochrome camera 10 are controlled.

When the first monochrome image data and the second monochrome image data are acquired, the control unit 40 generates a composite color image for the surface of the measurement object 100 using the first monochrome image data and the second monochrome image data . Here, the control unit 40 calculates the third monochrome image data using the first monochrome image data and the second monochrome image data, synthesizes the first monochrome image data, the second monochrome image data, and the third monochrome image data The process of generating the composite color image is the same as in the first embodiment described above.

Thus, even if a monochrome camera 10 is installed in a 2D / 3D measurement device using a moire pattern, it is possible to acquire a color image in the case of 2D, and to obtain a 3D image of black and white without loss of color information So that the utility of the 2D / 3D measuring device can be increased.

In the above-described embodiments, the first monochrome image data and the second monochrome image data are acquired by the monochrome camera 10, and the third monochrome image data and the second monochrome image data are used to calculate the third monochrome image data As an example.

On the other hand, the surface shape measuring apparatus according to the present invention includes a third light source 33 that irradiates the surface of the measurement object 100 with the third monochromatic light that is different from the first monochromatic light and the second monochromatic light, May be provided so that the monochrome camera 10 picks up the surface of the measurement object 100 in a state in which the third monochromatic light is irradiated from the third light source 33 to acquire the third monochrome image data.

Accordingly, the control unit 40 acquires the first monochrome image data, the second monochrome image data, and the third monochrome image data corresponding to the first monochromatic light, the second monochromatic light and the third monochromatic light, respectively, through the monochrome camera 10 , The acquired first monochrome image data, second monochrome image data, and third monochrome image data may be processed as R, G, and B data to generate a composite color image.

3 and 6, reference numeral 20 denotes a condenser lens 20 for condensing the light reflected from the measurement object 100 toward the monochrome camera.

In the second embodiment of the present invention, the surface shape measuring apparatus for 2D / 3D measurement uses a moire method. It is needless to say that the surface shape measuring apparatus according to the present invention is applicable to the 2D measurement among other types of 3D measurement equipment.

Although several embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various modifications may be made without departing from the principles and spirit of the invention . And the scope of the invention will be determined by the appended claims and their equivalents.

1 and 2 are views for explaining a color filter applied to a color camera and an interpolation method thereof,

3 is a diagram showing an example of a configuration of a surface shape measuring apparatus according to the first embodiment of the present invention,

4 is a diagram showing an example of a monochrome 2D image represented by first monochrome image data and second monochrome image data obtained through the surface shape measuring apparatus according to the first embodiment of the present invention,

Fig. 5 is a diagram showing an example of a composite color image generated using the first monochrome image data and the second monochrome image data of Fig. 4,

6 is a diagram showing an example of the configuration of the surface shape measuring apparatus according to the second embodiment of the present invention.

Description of the Related Art

10: monochrome camera 31: first light source

32: second light source 33: third light source

40:

Claims (3)

A surface shape measuring apparatus for picking up a 2D image of a surface of a measurement object, A first light source for irradiating the surface of the measurement object with the first monochromatic light; A second light source for irradiating a surface of the measurement object with second monochromatic light of a color different from the first monochromatic light; A monochrome camera for picking up the first monochromatic light and the second monochromatic light emitted from the first light source and the second light source and reflected from the surface of the measurement object; Color image data and second monochrome image data corresponding to the first monochromatic light and the second monochromatic light, respectively, in a state in which the first monochromatic light and the second monochromatic light are respectively irradiated to the surface of the measurement object, 1 image data, the first light source, the second light source, and the monochrome camera, and calculates third monochrome image data based on the first monochrome image data and the second monochrome image data, And a control unit for processing the monochrome image data and the third monochrome image data into R, G, and B data for mutually corresponding pixels to generate a composite color image for the surface of the measurement object; Wherein the first monochromatic light is any one of green light and blue light, and the second monochromatic light is red light. The method according to claim 1, The controller I_3rd_data = n × I_st_data ^k + m × I_2nd_data ^p where I_st_data is the first monochrome image data, I_2nd_data is the second monochrome image data, I_3rd_data is the third monochrome image data, n and k Is a constant given to the first monochrome image data for calculating the third monochrome image data, and m and p are constants given to the second monochrome image data for calculating the third monochrome image data) And said third black-and-white image data is calculated by said third black-and-white image data. 3. The method of claim 2, Wherein the monochrome camera is provided in the form of an area-scan camera or a line-scan camera.

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