JP2007286003A - Instrument, method, and program for measuring appearance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an appearance measuring instrument capable of measuring a work precisely by using a commercial scanner, or the like. <P>SOLUTION: The appearance measuring instrument measures the appearance of a work, such as a substrate and an electronic component, by using a scanner. A scale image acquisition means acquires a scale image, where the scanner fetches a scale in which a plurality of marks are aligned regularly. A work image acquisition means acquires a work image, where the scanner fetches the work. A restoration means restores the work image based on the mark in the scale image. More specifically, the restoration means performs image processing for correcting distortion, deviation, or the like occurring in the work image obtained by photographing. As a result, the work can be measured precisely by using the relatively inexpensive commercial scanner, or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an appearance measuring device, an appearance measuring method, and an appearance measuring program for measuring the appearance of a workpiece using a scanner.

  Conventionally, an appearance measuring apparatus for measuring the appearance of a workpiece such as a printed circuit board has been proposed. Specifically, the printed circuit board is photographed before and after mounting the electronic component, and measurement is performed based on the photographed image. For example, Patent Document 1 describes a technique for performing an inspection by correcting distortion appearing in an image of an inspection object. Further, Patent Document 2 describes a technique for taking an image of a printed circuit board to be inspected by a scanner as an inspection object image and comparing the correlation between the inspection object image from the scanner and the stored master image of the printed circuit board. ing.

JP 2002-181732 A JP 2002-296200 A

  However, with the techniques described in Patent Documents 1 and 2 described above, it has been impossible to perform highly accurate measurement on a workpiece with an inexpensive and simple apparatus configuration.

  Examples of the problem to be solved by the present invention are as described above. An object of the present invention is to provide an appearance measuring apparatus capable of performing high-precision measurement on a workpiece using a commercially available scanner or the like.

  According to the first aspect of the present invention, an appearance measuring apparatus that measures the appearance of a workpiece using a scanner has a scale image acquiring unit that acquires a scale image in which a scale in which a plurality of marks are regularly arranged is captured by the scanner. And a work image acquisition means for acquiring a work image obtained by capturing the work with the scanner, and a restoration means for restoring the work image based on the mark in the scale image.

  According to a sixth aspect of the invention, an appearance measuring method for measuring the appearance of a workpiece using a scanner is a scale image acquiring step for acquiring a scale image obtained by capturing a scale in which a plurality of marks are regularly arranged by the scanner. And a work image obtaining step for obtaining a work image obtained by capturing the work by the scanner, and a restoration step for restoring the work image based on the mark in the scale image.

  According to the seventh aspect of the present invention, an appearance measurement program executed by a computer that acquires and processes an image photographed by a scanner is a scale image in which a scale in which a plurality of marks are regularly arranged is captured by the scanner. The computer functions as a scale image acquisition unit that acquires the workpiece image, a workpiece image acquisition unit that acquires a workpiece image obtained by capturing the workpiece by the scanner, and a restoration unit that restores the workpiece image based on the mark in the scale image. Let

  In one embodiment of the present invention, an appearance measuring apparatus that measures the appearance of a workpiece using a scanner has a scale image acquisition unit that acquires a scale image in which a scale in which a plurality of marks are regularly arranged is captured by the scanner. And a work image acquisition means for acquiring a work image obtained by capturing the work with the scanner, and a restoration means for restoring the work image based on the mark in the scale image.

  The above-described appearance measuring apparatus is an apparatus that measures the appearance of a workpiece such as a substrate or an electronic component using a scanner. The scale image obtaining unit obtains a scale image obtained by taking a scale in which a plurality of marks are regularly arranged by a scanner, and the work image obtaining unit obtains a work image obtained by taking a work by the scanner. The restoration means restores the work image based on the mark in the scale image. In other words, the restoration unit performs image processing for correcting distortion, deviation, and the like occurring in the work image obtained by photographing. Thereby, it is possible to perform highly accurate measurement on a workpiece using a relatively inexpensive commercially available scanner or the like.

  In one aspect of the appearance measurement apparatus, the restoration unit calculates a position on the work image corresponding to a pixel position of the restored image to be obtained by restoration based on the position of the mark on the scale image. Work image position calculation means is provided. In this case, the work image position calculation means calculates a position on the work image corresponding to the pixel position of the restored image to be obtained by restoration using a linear interpolation method or the like based on the position of the mark.

  In another aspect of the appearance measuring apparatus, the restoration unit assigns data to be assigned to the position on the workpiece image obtained by the workpiece image position calculation unit, and data around the position on the workpiece image. To interpolate. Thereby, even when data does not exist at the calculated work image position, data to be assigned to the position can be obtained with high accuracy.

  Suitably, said external appearance measuring apparatus can use at least any one of a board | substrate and an electronic component as a workpiece | work.

  Preferably, in the above-described appearance measuring apparatus, the work image acquisition unit can acquire an image in which an area limited by a mask is captured by the scanner. For example, when the workpiece is an electronic component, the workpiece image acquisition unit acquires an image of the workpiece placed near the center of the scanner using a mask. Thereby, the work image appropriately captured from the front can be acquired.

  In another aspect of the present invention, an appearance measurement method for measuring the appearance of a workpiece using a scanner includes a scale image acquisition step of acquiring a scale image in which a scale in which a plurality of marks are regularly arranged is captured by the scanner, A workpiece image acquisition step of acquiring a workpiece image obtained by capturing the workpiece by the scanner; and a restoration step of restoring the workpiece image based on the mark in the scale image.

  In another aspect of the present invention, an appearance measurement program executed by a computer that acquires and processes an image photographed by a scanner is a scale image obtained by capturing a scale in which a plurality of marks are regularly arranged by the scanner. Causing the computer to function as scale image acquisition means for acquiring, work image acquisition means for acquiring a work image obtained by capturing the work by the scanner, and recovery means for recovering the work image based on the mark in the scale image .

  Also with the above-described appearance measurement method and appearance measurement program, high-precision measurement can be performed on a workpiece with an inexpensive and simple apparatus configuration.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[System configuration]
First, the configuration of a system to which an appearance measuring apparatus according to an embodiment of the present invention is applied will be described with reference to FIG. FIG. 1 is a diagram illustrating a schematic configuration of an appearance measurement system 100.

  The appearance measurement system 100 includes a personal computer (PC) 1 and a scanner 2. The appearance measurement system 100 performs measurement using a printed circuit board as a workpiece. Specifically, the appearance measurement system 100 is a system that measures the position of a round formed on a printed circuit board. In addition, although the wiring etc. are formed in the printed circuit board used as a workpiece | work, an electronic component etc. are not mounted.

  The scanner 2 captures an image of a workpiece and supplies image data S2 obtained by the capture to the PC 1. For example, as the scanner 2, a known flatbed scanner, a sheet feed scanner, a film scanner, or the like can be used.

  The PC 1 includes an image processing unit 1a and an image display unit 1b. The image processing unit 1a includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and performs image processing on the image data S2 supplied from the scanner 2. Specifically, the image processing unit 1a performs image processing that corrects distortion, displacement, and the like that occur in an image of a work obtained by photographing (hereinafter referred to as “work image”). In other words, the image processing unit 1a performs image processing for generating an image obtained by restoring the work image (hereinafter referred to as “restored image”). Then, the image processing unit 1a performs measurement of a round position formed on the printed circuit board based on the restored image obtained by the image processing. Thus, the image processing unit 1a functions as an appearance measuring device according to the present invention. On the other hand, the image display unit 1b displays a work image photographed by the scanner 2, a restored image subjected to image processing by the image processing unit 1a, and the like.

[Image processing method]
Next, an image processing method executed by the image processing unit 1a will be described.

  In this embodiment, the workpiece is photographed by the scanner 2 and image processing for restoring the obtained workpiece image is performed. This is because the work image obtained by the scanner 2 is distorted or displaced due to the characteristics of the scanner 2 or the like, so that even if the work image is used as it is, high-precision measurement can be performed. It is not possible. Therefore, in the present embodiment, a process for generating a restored image in which distortion or deviation generated in the work image is corrected is performed.

  More specifically, in this embodiment, image processing is performed on a work image using a scale in which a plurality of marks are regularly arranged. Specifically, first, an image of a scale (hereinafter referred to as “scale image”) is taken in by the scanner 2, and the position (coordinates) of the mark in the scale image is acquired and stored. Next, the work image is taken in by the scanner 2 and the work image is restored based on the stored mark positions.

  Here, the image processing method according to the present embodiment will be described in detail with reference to FIGS. 2 to 6.

  FIG. 2 is a diagram for explaining a procedure for capturing a scale image. FIG. 2A is a diagram showing the scale 3 used in this embodiment. The scale 3 is composed of a glass plate or the like, and circular marks 3a are edged in a matrix shape. The marks 3 a are arranged in a lattice pattern in the scale 3. For example, the mark 3a has a diameter of 2 (mm) and is arranged on the matrix at a pitch of 8 (mm), and the absolute accuracy is suppressed within 7 (μm / 20 ° C.) over the entire area.

  FIG. 2B is a diagram showing how the scale 3 is set in the scanner 2. FIG. 2C is a diagram showing the method for setting the scale 3 in detail. As shown in FIG. 2 (c), the scale 3 is set on the scanner 2 by pressing the corner 3 b of the scale 3 against a reference corner 2 a (for example, marked) on the glass surface of the scanner 2. . Then, after such setting is completed, the scale 3 is photographed. Note that the resolution when photographing the scale 3 is set to the same value as the resolution when photographing the workpiece 4.

  FIG. 3 is a diagram for explaining a method of capturing a scale image. FIG. 3 is a diagram showing a scale image 13 of the scale 3 and shows an enlarged image in the vicinity of the corner 3 b of the scale 3. As described above, due to the characteristics of the scanner 2 and the like, the image taken by the scanner 2 is distorted, so the mark image 13a in the scale image 13 is shifted from the actual position of the mark 3a. Yes.

  When an image as shown in FIG. 3 is obtained, the image processing unit 1a obtains and stores the coordinates (real value) of the mark image 13a. Specifically, the image processing unit 1a stores the coordinates of the center of gravity of the mark image 13a by recognizing the mark image 13a. More specifically, the image processing unit 1a stores the obtained coordinates in real array data. In this case, the image processing unit 1a stores the X coordinate in “Smxp [x] [y]” and the Y coordinate in “Smyp [x] [y]”. It should be noted that “x = 0, 1, 2, 3,...” And “y = 0, 1, 2, 3,. Further, the X coordinate and the Y coordinate are defined with the image position 13b (corresponding to the corner 3b) corresponding to the corner 3b as the origin.

  FIG. 4 is a diagram showing a procedure for setting the workpiece 4 to the scanner 2. After the scale image is captured as described above, the scale 3 is extracted. Thereafter, the work 4 is set on the scanner 2 as shown in FIG.

  FIG. 4B is a diagram showing the method for setting the workpiece 4 in detail. As described above, when the work 4 is set, the scale 3 is taken out. However, in FIG. 4B, for convenience of explanation, the scale 3 is overlaid with a broken line. A scale 3 indicated by a broken line indicates a position set at the time of shooting. In this case, the workpiece 4 is set in the hatching area 70 inside the outermost mark 3 a on the scale 3. For example, a frame or the like can be set in advance on the glass surface of the scanner 2 so that the workpiece 4 can be placed only in the hatched area 70.

  FIG. 4C is a diagram illustrating a preferred example of a method for setting the workpiece 4. FIG. 4C is an enlarged view showing the vicinity of the corner 3b in the scale 3 in FIG. 4B. In this case, the workpiece 4 is set so that the corner 4a of the workpiece 4 is located in a region 71 surrounded by the four marks 3a1, 3a2, 3a3, 3a4 located near the corner 3b of the scale 3. As a result, the subsequent processing can be performed with reference to the mark 3a1 located in the immediate vicinity of the corner 3b.

  FIG. 5 is a diagram for explaining a method for capturing a work image and a restoration method for the work image. In FIGS. 5A to 5C, images corresponding to the scale 3 (shown by broken lines) are displayed in an overlapping manner for convenience of explanation.

  FIG. 5A is a diagram for explaining a method of capturing a work image. Specifically, FIG. 5A shows an image 20 before the work 4 is captured as a work image. In other words, the image 20 corresponds to an image used for capturing a work image, not bitmap data. A person who performs measurement (hereinafter also simply referred to as “measurer”) refers to the image 20 and designates the imaging range 73 of the scanner 2. In this case, the measurer designates a range in which the origin 21 (corresponding to the corner 3b of the scale 3) is included and the entire image 24 showing the workpiece 4 is included. For example, the measurer designates the imaging range 73 by operating a mouse (not shown) of the PC 1 based on the image displayed on the image display unit 1b. Thus, after the designation of the photographing range 73 is completed, the work 2 is photographed by the scanner 2. In the above, an example in which the measurer manually specifies the shooting range 73 is shown, but instead, the image processing unit 1a can automatically set the shooting range 73 by recognizing the workpiece 4 as an image. It is.

  FIG. 5B shows an image 30 including a work image 34 photographed by the scanner 2. The image 30 corresponds to an image shot based on the shooting range 73 designated by the measurer. The image 30 obtained by photographing is stored in the image processing unit 1a as bitmap data. Looking at the image 34, it can be seen that the work image 34 is distorted. It can also be seen that the position of the mark image 33a indicated by the broken line is also shifted. These are due to the characteristics of the scanner 2 and the like.

  FIG. 5C shows an image 40 obtained by restoring the image 30 including the work image 34. The image processing unit 1a performs image processing (details will be described later) for restoring the image 30 based on the coordinates (see FIG. 3) of the mark 3a stored when the scale image is acquired. Thereby, a restored image 44 corresponding to the work 4 with no distortion or the like is obtained. In this case, it can be seen that the position of the image 43a (indicated by a broken line) indicating the mark 3a is not shifted. Note that the outer region of the outermost mark 3a of the scale 3 is not restored.

  Next, image processing according to the present embodiment will be described with reference to FIG. FIG. 6 is a flowchart illustrating image processing according to the present embodiment. This process is mainly executed by the image processing unit 1a of the PC 1. In the flowchart of FIG. 6, the process indicated in parentheses indicates the process performed by the measurer.

  First, in step S <b> 101, the measurer sets the scale 3 on the scanner 2. In this case, the measurer sets the scale 3 to the scanner 2 by pressing the corner 3b of the scale 3 against the reference corner 2a on the glass surface of the scanner 2 (see FIG. 2C). Then, the process proceeds to step S102.

  In step S102, the scanner 2 executes scale 3 imaging. The scanner 2 supplies a scale image obtained by photographing to the image processing unit 1a as a signal S2. In this case, the image processing unit 1a stores the coordinates where the mark image is located by recognizing the mark image in the scale image. Specifically, the image processing unit 1a stores the X coordinate in “Smxp [x] [y]” and the Y coordinate in “Smyp [x] [y]”. When the above process ends, the process proceeds to step S103.

  In step S <b> 103, the measurer removes the scale 3 from the scanner 2, and then sets the work 4 on the scanner 2. In this case, the measurer sets the workpiece 4 in the hatching area 70 inside the outermost peripheral mark 3a on the scale 3 (see FIG. 4B). After the workpiece 4 is set in this way, the image of the workpiece 4 is captured by the scanner 2. Then, the image processing unit 1a displays the captured image on the image display unit 1b. This image has not been converted into bitmap data. When the process of step S103 is completed, the process proceeds to step S104.

  In step S104, the measurer refers to the image displayed on the image display unit 1b in step S103 and designates a range in which the origin 21 is included and the entire image 24 showing the workpiece 4 is included (step S104). (See FIG. 5 (a)). That is, the measurer designates the shooting range 73 by the scanner 2. Then, the process proceeds to step S105.

  In step S105, the workpiece 4 is shot based on the shooting range 73 designated by the measurer in step S104. In this case, the image processing unit 1a stores an image (work image) obtained by photographing as bitmap data. Then, the process proceeds to step S106.

  In step S106, the image processing unit 1a executes image processing for restoring the work image acquired in step S105 based on the scale image acquired in step S102. In this case, the image processing unit 1a performs restoration on the work image based on the coordinates of the mark image in the scale image. When the above process ends, the process exits the flow.

  By executing the processing shown in FIG. 6, it is possible to obtain an appropriate image of the workpiece 4 in which no deviation or distortion has occurred. Therefore, according to the present embodiment, it is possible to perform highly accurate measurement on the workpiece 4 using a relatively inexpensive commercially available scanner or the like.

  In the above example, the measurer manually sets the scale 3 and the workpiece 4 on the scanner 2, but instead, the scale 3 and the workpiece 4 are automatically set at predetermined positions on the scanner 2 by a transport robot or the like. It is also possible to set

  Further, it is not necessary to take a scale image with the scanner 2 every time the workpiece 4 is measured. It is also possible to measure a plurality of workpieces 4 using a scale image once photographed. In this case, when the scanner 2 is moved, or when measurement is performed after a certain amount of time has passed since the scale image was captured, the scale image is captured again by the scanner 2 and used. It is preferable to perform image processing.

[How to restore]
Next, a method for restoring the work image will be described with reference to FIGS. In this embodiment, first, the position on the work image corresponding to the pixel position of the restored image to be obtained by restoration is calculated based on the position of the mark on the scale image. Next, data (color data or the like) to be assigned to the position on the obtained work image is obtained by interpolation using data around the position. By performing the above processing for all the pixels constituting the restored image, a restored image corresponding to the work image is obtained.

(Work image position calculation method)
The procedure for calculating the position on the work image corresponding to the pixel position of the restored image will be described below.

  FIG. 7 is a diagram for explaining a method of calculating the position on the work image corresponding to the pixel position of the restored image. FIG. 7 shows images of the scale 3 and the workpiece 4. Specifically, FIG. 7A shows a work image taken by the scanner 2, and FIG. 7B shows a restored image corresponding to the work image. In this case, for convenience of explanation, the scale image and the restored image corresponding thereto are displayed in an overlapping manner.

  Here, it is considered to obtain a position (Sxp, Syp) in the work image corresponding to an arbitrary coordinate (Rxp, Ryp) in the restored image. “Rxp” and “Ryp” are integer values, and coordinates (Rxp, Ryp) correspond to one pixel.

  First, the mark pitch coordinates based on the mark 3a of the scale 3 are defined, and the mark pitch coordinates (Rxm, Rym) of the coordinates (Rxp, Ryp) are obtained. Assuming that the resolution of the scanner 2 is Dpi [DPI], the pixel size PSize [mm] can be obtained by Expression (1).

PSize = 25.4 / Dpi expression (1)
If the mark-to-mark distance is Mp [mm], the mark pitch coordinates (Rxm, Rym) of the designated pixel (Rxp, Ryp) can be expressed by the expressions (2-1) and (2- 2).

Rxm = Rxp · PSize / Mp Formula (2-1)
Rym = Ryp · PSize / Mp Formula (2-2)
Next, the coordinates of the four marks 3a surrounding the position (Sxp, Syp) described above are obtained. FIG. 8 is a diagram showing the relationship between the position (Sxp, Syp) and the coordinates (Xtl, Ytl), (Xtr, Ytr), (Xbl, Ybl), (Xbr, Ybr) of the four marks 3a. The coordinates of the four marks 3a are obtained when a scale image is taken, and are stored in the image processing unit 1a (see the process in step S102 in FIG. 6). In this case, the X coordinate and Y coordinate of the four marks 3a surrounding the position (Sxp, Syp) are expressed by the following equations (3-1) to (3-8), respectively.

Xtl = Smxp [(int) Rxm] [(int) Rym] Formula (3-1)
Ytl = Smyp [(int) Rxm] [(int) Rym] Formula (3-2)
Xtr = Smxp [(int) Rxm + 1] [(int) Rym] Expression (3-3)
Ytr = Smyp [(int) Rxm + 1] [(int) Rym] Expression (3-4)
Xbl = Smxp [(int) Rxm] [(int) Rym + 1] Formula (3-5)
Ybl = Smyp [(int) Rxm] [(int) Rym + 1] Equation (3-6)
Xbr = Smxp [(int) Rxm + 1] [(int) Rym + 1] Equation (3-7)
Ybr = Smyp [(int) Rxm + 1] [(int) Rym + 1] Equation (3-8)
Note that “(int)” in the expressions (3-1) to (3-8) means that the real part is extracted. For example, “(int) Rxm” indicates the real part of “Rxm”.

  Next, since the coordinates of the four marks 3a described above are distorted, it is considered that the position (Sxp, Syp) is obtained by performing linear interpolation using the coordinates of these marks 3a. Specifically, as shown in FIG. 8, it is defined by the coordinates (Xtl, Ytl), (Xtr, Ytr), (Xbl, Ybl), (Xbr, Ybr) of the mark 3a and the position (Sxp, Syp). The position (Sxp, Syp) is expressed using the point P1 and the point P2 to be performed.

  Here, if the fractional parts of the mark pitch coordinates (Rxm, Rym) of the pixels in the restored image are “FRxm” and “FRym”, respectively, the fractional parts FRxm and FRym are expressed by the following equations (4-1) and It is represented by Formula (4-2).

FRxm = Rxm- (int) Rxm formula (4-1)
FRym = Rym− (int) Rym expression (4-2)
Using these decimal parts FRxm and FRym, the coordinates (S1xp, S1yp) of the point P1 are expressed by the following equations (5-1) and (5-2).

S1xp = FRxm (Xtr−Xtl) + Xtl formula (5-1)
S1yp = FRxm (Ytr−Ytl) + Ytl formula (5-2)
Further, the coordinates (S2xp, S2yp) of the point P2 are expressed by the following equations (6-1) and (6-2).

S2xp = FRxm (Xbr−Xbl) + Xbl Formula (6-1)
S2yp = FRxm (Ybr−Ybl) + Ybl formula (6-2)
By performing linear interpolation using the coordinates of the above points P1 and P2, the position (Sxp, Syp) can be obtained by Expression (7-1) and Expression (7-2).

Sxp = FRym (S2xp−S1xp) + S1xp equation (7-1)
Syp = FRym (S2yp-S1yp) + S1yp formula (7-2)
(Interpolation calculation method)
Since the coordinates (Sxp, Syp) of the workpiece image can be obtained by the above-described procedure, data corresponding to the coordinates (Sxp, Syp) (hereinafter also referred to as “color data”) is acquired. This can be written in the coordinates (Rxp, Ryp) of the restored image. However, there are the following problems when performing this processing.

  The coordinate value of the coordinate (Rxp, Typ) in the restored image is “integer”, but the coordinate (Sxp, Syp) of the work image corresponding to this is likely to be “real number”. For example, as shown in FIG. 9, consider the case where the coordinates (Sxp, Syp) of the obtained workpiece image are (55.35, 85.75). In this case, there is no color data at the position (55.35, 85.75). On the other hand, the color data is stored in the points Q1 to Q4 (specifically, (55,85), (55,86), (56,85), (56,86)) surrounding the position of (55.35,85.75)). Exists. Therefore, in this embodiment, when there is no color data on the coordinates (Sxp, Syp) of the obtained work image, the coordinates are obtained by performing interpolation using the color data around the coordinates (Sxp, Syp). Color data corresponding to (Sxp, Syp) is obtained.

  FIG. 10 is a diagram for explaining an interpolation calculation method. Here, it is considered to obtain the color data of the point Ts located at (Sxp, Syp). The point Ts does not have corresponding color data at that position. Further, color data corresponding to these positions exist at the four points T1, T2, T3, and T4 surrounding the point Ts. Specifically, the points T1, T2, T3, and T4 have color data C1, C2, C3, and C4, respectively. Here, a case where grayscale color data is used will be described as an example.

  The fractional parts FSxp and FSyp in the X coordinate and Y coordinate of Ts (Sxp, Syp) are expressed by Expression (8-1) and Expression (8-2), respectively.

FSxp = Sxp− (int) Sxp equation (8-1)
FSyp = Syp- (int) Syp formula (8-2)
Next, it is assumed that the color data of the points Tt and Tb defined by the point Ts and the points T1, T2, T3, and T4 are obtained using the fractional parts FSxp and FSyp of Ts (Sxp, Syp). The color data Ct at the point Tt is expressed by Expression (9) based on the weight of the distance from the points T1 and T2 located on the left and right sides.

Ct = C1 (1−FSxp) + C2 ・ FSxp Equation (9)
Similarly, the color data Cb at the point Tb is expressed by Expression (10).

Cb = C3 (1−FSxp) + C4 · FSxp Formula (10)
By using the color data Ct and the color data Cb thus obtained, the color data Cs of (Sxp, Syp) can be obtained by the following equation (11).

Cs = Ct (1−FSyp) + Cb · FSyp formula (11)
By writing the color data Cs obtained as described above into the coordinates (Rxp, Ryp) of the restored image, the processing of one pixel of the restored image is completed. Thereafter, the position on the work image is calculated and the interpolation operation is performed on the other pixels of the restored image by the same procedure. Then, when these processes are completed, the process is further performed on other pixels. That is, these processes are executed for all the pixels constituting the restored image of the work 4. Thereby, a restored image corresponding to the work image can be obtained.

  In the above description, an example in which the image is grayscale data is shown. However, when the image is RGB data, the above procedure is repeated three times for “R”, “G”, and “B”. Just do it.

  As described above, in this embodiment, the image processing unit in the PC that measures the appearance of the workpiece using the scanner acquires a scale image obtained by capturing a scale in which a plurality of marks are regularly arranged by the scanner. The work image obtained by capturing the work with the scanner is acquired, and the work image is restored based on the mark in the scale image. Thereby, it is possible to perform highly accurate measurement on a workpiece using a relatively inexpensive commercially available scanner or the like.

[Modification]
Next, a modification of the above embodiment will be described.

  In the above, an example in which measurement is performed on a printed circuit board has been described. However, in a modified example, measurement is performed using an electronic component as a workpiece instead. In this case, the printed circuit board has almost no thickness, but the electronic component has a thickness, and therefore the procedure for performing the measurement is different from the above-described embodiment. Specifically, when a thick workpiece is photographed by the scanner 2, the workpiece may be photographed obliquely. Therefore, in the modification, measures are taken to prevent this.

  Specifically, in the modification, in order to prevent the workpiece from being obliquely photographed by the scanner 2, the workpiece is placed near the center of the glass surface of the scanner 2 and photographing is performed. More specifically, the work is set after covering the glass surface of the scanner 2 with a mask so that the work is appropriately set near the center of the glass surface of the scanner 2. In the modification, since the workpiece has a thickness, it is preferable to use a line sensor type scanner as the scanner 2.

  FIG. 11 is a diagram for explaining a procedure for setting a workpiece. FIG. 11A shows a procedure for setting the mask 7. The mask 7 is formed of a black flat plate, and holes 7a and 7b are provided near the center. The hole 7a has a rectangular shape, and the hole 7b has a circular shape. The mask 7 is set by pressing the corner of the mask 7 against the reference corner 2a (see FIG. 2C) in the scanner 2. In this case, the mask 7 is set so that the hole 7b is positioned on the reference corner 2a side.

  FIG. 11B shows a procedure for setting two works 8a and 8b (hereinafter, the two works 8a and 8b are collectively referred to as “work 8”). In this case, the workpiece 8 is set with respect to the scanner 2 in which the mask 7 is still set. Specifically, the workpiece 8 is placed in the hole 7 a of the mask 7.

  FIG. 12 is a diagram for explaining a method of capturing a work image. FIG. 12A is a diagram for explaining a method of capturing a work image. Specifically, FIG. 12A shows an image 50 before the work 8 is captured as a work image. The image 50 corresponds to an image used for capturing a work image, not bitmap data. Looking at the image 50, it can be seen that the portion where the mask 7 is present (except for the portion provided with the holes 7a and 7b) is dark. The measurer refers to such an image 50 and designates the imaging range 80 of the scanner 2. In this case, the measurer starts the imaging range 80 from the vicinity of the center of the image 57b corresponding to the hole 7b and specifies the range so that the entire images 58a and 58b corresponding to the workpieces 8a and 8b are included.

  FIG. 12B shows an image 60 including work images 68a and 68b photographed by the scanner 2. The image 60 corresponds to an image photographed based on the photographing range 80 designated by the measurer. The image processing unit 1a stores the image 60 obtained by photographing as bitmap data. Then, the image processing unit 1a generates the restored image of the work 8 by executing the above-described image processing on the image 60.

  In the modified example, since the work 8 is set in the hole 7a of the mask 7, the imaging range 80 for the work 8 is limited to some extent, and therefore the scale image of the scale 3 is acquired by the following procedure. FIG. 13 is a diagram for explaining a procedure for acquiring a scale image according to a modification. FIG. 13 shows an image 87a corresponding to the hole 7a of the mask 7 and an image 87b corresponding to the hole 7b superimposed on the scale image 83 corresponding to the scale 3 by broken lines. Thus, it can be seen that the entire image 83a corresponding to the mark 3a of the scale 3 is included in the image 87b corresponding to the hole 7b. This is because the position of the hole 7b of the mask 7 is designed so that the entire image 83a is included in the image 87b.

  In the modified example, as indicated by a broken line area 90, a scale image is captured by setting an area in which an image 87b corresponding to the hole 7b and an image 87a corresponding to the hole 7a are at least included as an imaging range. As described above, when the shooting range 80 of the workpiece 8 is designated, the shooting range 80 is always included in the shooting region 90 of the scale 2, so that the workpiece image can be appropriately restored using the scale image. It becomes possible. In this case, image processing can be appropriately performed using the mark 3 positioned in the hole 7b of the mask 7 as a reference. Further, according to the modification, it is not necessary to hold the entire scale 3 image as the scale image, so that the storage capacity and the calculation amount can be reduced.

  In addition, although the example which performs a measurement using the printed circuit board and the electronic component as the workpiece 4 has been described above, in another example, the appearance measurement apparatus performs an inspection such as a mounting position inspection of the electronic component on the printed circuit board. be able to. In still another example, it is possible to measure the dimensions of an electronic component.

It is a figure which shows schematic structure of the external appearance measurement system which concerns on a present Example. It is a figure for demonstrating the procedure which takes in a scale image. It is a figure for demonstrating the method to capture a scale image. It is a figure which shows the procedure which sets a workpiece | work to a scanner. It is a figure for demonstrating the method to take in a workpiece | work image, and the restoration method with respect to a workpiece | work image. It is a flowchart which shows the image processing which concerns on a present Example. It is a figure for demonstrating the work image position calculation method. It is a figure for demonstrating the linear interpolation method performed in order to obtain | require a workpiece | work image position. It is a figure for demonstrating the malfunction at the time of calculating | requiring color data. It is a figure for demonstrating the interpolation calculation method concretely. In the modification, it is a figure for demonstrating the procedure which sets a workpiece | work. FIG. 10 is a diagram for describing a method for capturing a work image in a modification. It is a figure for demonstrating the acquisition procedure of the scale image which concerns on a modification.

Explanation of symbols

1 PC
DESCRIPTION OF SYMBOLS 1a Image processing part 1b Image display part 2 Scanner 3 Scale 4, 8 Work piece 7 Mask 7a, 7b Hole 100 Appearance measuring system

Claims (7)

An appearance measuring device that measures the appearance of a workpiece using a scanner,
A scale image acquisition means for acquiring a scale image obtained by capturing a scale in which a plurality of marks are regularly arranged by the scanner;
Workpiece image acquisition means for acquiring a workpiece image obtained by capturing the workpiece with the scanner;
An appearance measuring apparatus comprising: a restoration unit that restores the workpiece image based on the mark in the scale image.   The restoration unit includes a work image position calculation unit that calculates a position on the work image corresponding to a pixel position of a restored image to be obtained by restoration based on the position of the mark on the scale image. The appearance measuring device according to claim 1.   The restoration means further includes an interpolation calculation means for obtaining the data to be assigned to the position on the work image obtained by the work image position calculation means by interpolating using data around the position on the work image. The appearance measuring apparatus according to claim 2, further comprising:   The appearance measuring apparatus according to claim 1, wherein the workpiece is at least one of a substrate and an electronic component.   The appearance inspection apparatus according to claim 1, wherein the work image acquisition unit acquires an image obtained by capturing an area limited by a mask with the scanner. An appearance measurement method for measuring the appearance of a workpiece using a scanner,
A scale image obtaining step for obtaining a scale image obtained by capturing a scale in which a plurality of marks are regularly arranged by the scanner;
A work image acquisition step of acquiring a work image obtained by capturing the work with the scanner;
And a restoration step of restoring the workpiece image based on the mark in the scale image. An appearance measurement program executed by a computer that acquires and processes an image captured by a scanner,
A scale image obtaining means for obtaining a scale image obtained by capturing a scale in which a plurality of marks are regularly arranged by the scanner;
A workpiece image acquisition means for acquiring a workpiece image obtained by capturing the workpiece with the scanner;
An external appearance measurement program that causes the computer to function as a restoration unit that restores the work image based on the mark in the scale image.

Images