JP2007101565A - Height data processing method - Google Patents

Abstract

There is provided a height data processing method capable of measuring tact time significantly and accurately measuring height.
The protrusions cut by the line light are imaged and the height data of the protrusions obtained by the light cutting method is processed. First, the image of the projecting object is extracted as gradation data for each pixel, the gradation flatness of the surrounding pixels is examined for each pixel, and if it is not flat, the target pixel is filtered. And binarization is performed on the gradation data on which the gradation processing has been performed, and the image of the protruding object is converted into binary data (steps S17 and S27). In such a configuration, since the gradation data of the imaged pixels is flattened and then binarized, stable height data can be obtained.
[Selection] Figure 5

Description

  The present invention relates to a height data processing method, and more particularly, to a height data processing method for measuring a fine height such as cream solder printed by a cream solder printer used in a surface mounting system.

  Conventionally, a three-dimensional recognition device using a light cutting method is known as a device for recognizing a three-dimensional shape and measuring the height. FIG. 14 shows a three-dimensional recognition apparatus using this light cutting method. The line light 122 from the line light generator 121 that is a light source is projected at a predetermined angle from obliquely above the object to be measured 123, and an image formed along the surface shape formed on the surface of the object to be measured 123 is vertical. The image is taken by the CCD camera 124 from above. The image captured by the CCD camera 124 is A / D converted by the CCD camera controller 125 and captured by the image capturing device 126. Then, the acquired data is converted into the three-dimensional coordinates of the measurement object 123 by the coordinate calculator 127.

  In a cream solder height measuring apparatus that is used by being incorporated in a cream solder printer, a portion (measurement unit) 128 surrounded by a dotted line in FIG. 14 is incorporated in an XY moving gantry (XY moving mechanism). Is done. First, when a printed wiring board is carried into the cream solder printing machine, after the positioning of the wiring board and the stencil is completed, the measurement unit 128 is moved from the initial expected avoidance position to the target measurement position by the XY moving gantry. Then, the measurement unit captures an image of the line light formed on the pad surface (resist surface) on the wiring board, which is the object to be measured, by the CCD camera 124 and then retreats to the initial expected avoidance position. Next, cream solder is printed on the pad surface of the wiring board. After the printing on the pad surface of the wiring board is completed, the measurement unit 128 is moved again to the target measurement position by the XY moving gantry, and the image of the line light formed along the shape of the cream solder is displayed on the CCD camera 124. Then, the image is moved back to the first expected avoidance position.

  From the above imaging data, the center-of-gravity position coordinates in the height direction of the pad surface of the wiring board and the center-of-gravity position coordinates in the height direction of the cream solder portion are calculated. Then, from the subtraction of the center of gravity position coordinate in the height direction of the pad surface of the wiring board and the center of gravity position coordinate in the height direction of the cream solder part, the height of the cream solder part after printing is determined with reference to the pad surface of the wiring board. calculate. And the average height of the cream solder part over each pad surface is calculated.

  In order to obtain a three-dimensional shape, a plurality of data with different light cutting positions are required. For example, assume that light cutting is performed at a pitch of 50 μm in order to obtain a three-dimensional shape of cream solder printed on a pad having a length of 2 mm. In this case, before printing the cream solder, an image of line light formed on the pad surface of the wiring board is taken 40 times by the CCD camera while changing the position of light cutting. Furthermore, after the cream solder is printed, it is necessary to capture the image of the line light formed along the shape of the cream solder 40 times while changing the light cutting position with a CCD camera. Therefore, the total number of times of imaging by the CCD camera is 80 times. Similarly, the total number of micro movements of the measurement unit is 80 times.

  However, in a cream solder height measuring device that is used by being incorporated in a conventional cream solder printing machine, the image of the line light before printing and the image of the line light after printing are picked up by a CCD camera and the cream solder is used. The height of must be calculated. For this reason, there is a problem that the tact time becomes long and the performance of the entire semiconductor surface mounting system is lowered.

  Furthermore, in order to change the light cutting position minutely, the heavy measurement unit equipped with the CCD camera must be moved. For the XY moving gantry, the skip function to the target measurement position and the measurement purpose There is a problem that the servo system for driving the XY moving gantry is complicated because it must have two functions of minute movement at the position.

  Accordingly, the present invention has been made to solve such problems, and it is an object of the present invention to provide a height data processing method capable of measuring the accurate height by greatly improving the tact time. Let it be an issue.

The present invention
In the height data processing method of processing the height data of the protrusion obtained by imaging the protrusion cut by the line light and obtained by the light cutting method,
The image of the protrusion is taken out as gradation data for each pixel,
Check the flatness of the gradation of the surrounding pixels for each pixel,
If it is not flat, perform gradation processing to filter the target pixel,
The gradation data subjected to the gradation processing is binarized to convert an image of a protruding object into binary data.

Further, the present invention provides a height data processing method for processing the height data of a protrusion obtained by light cutting by imaging a protrusion cut by line light.
The image of the protrusion is taken out as binary data of pixels arranged in rows and columns,
Filter the binarized data,
When a blank line is obtained as a result of the filter processing, data is embedded in the blank line according to the binarized data array of the preceding and following lines.

  In the height data processing of the present invention, since the gradation data of the imaged pixel is flattened and then binarized, stable height data can be obtained. If binary data is filtered and a blank line is generated as a result, data is embedded in the blank line according to the binarized data array in the preceding and subsequent lines. A certain height data is required.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

[Basic configuration]
FIG. 1 is a basic configuration diagram of main optical components of a three-dimensional measuring apparatus showing an embodiment of the present invention, and FIG. 2 is a side view thereof. In each figure, reference numeral 1 denotes a laser diode as a laser light source. The laser light emitted from the laser diode 1 is collimated by a collimator lens 2 into a parallel light beam 1a parallel to the optical center axis. The laser parallel light beam 1a enters a light projecting unit 7 in which a focus lens 3, a light projecting mirror 4, and a line generator lens 5 are incorporated. The laser light beam is narrowed down to become spot light by the focus lens 3 in the light projecting unit 7, reflected by the light projecting mirror 4 at an angle of 45 degrees with respect to the vertical axis (Z direction), and by the line generator lens 5. The line light 9 having a width of 14 to 20 μm and a length of 10 mm is formed, and the line light 9 is formed in the X direction on the object to be measured (cream solder or a wiring board on which it is printed) 11.

  Scattered and reflected light from the object to be measured 11 is imaged by a non-interlaced CCD camera 6 having a field of view of 6.4 mm × 4.8 mm arranged so that the optical axis 6a is a vertical axis. Further, the light projecting unit 7 is attached to the shaft 8a of the linear motor 8, and the linear motor 8 performs linear motion with a stroke of about 10 mm in the Y direction, as shown by double arrows. It reciprocates parallel to the light beam 1a. With this movement of the light projecting unit 7, the line light 9 moves in the direction perpendicular to the X direction in which the line light extends.

[Circuit configuration (data acquisition)]
FIG. 3 is a block diagram showing a circuit configuration for acquiring image data of an object to be measured in the three-dimensional measuring apparatus. In the figure, a linear motor drive command device 31 receives a start signal from the CPU 44, outputs a command pulse train for driving the linear motor to the linear motor driver 32, and moves the linear motor 8 by 0.25 μm per pulse. The linear motor drive commander 31 simultaneously sends a forward / reverse signal to an LD (laser diode) on / CCD trigger timing decoder (hereinafter referred to as timing decoder) 35, and the linear motor 8 moves in either the forward direction or the reverse direction. Let them know.

  The linear motor driver 32 receives the command pulse train to drive the linear motor, receives the signal indicating the actual position from the position encoder 8b built in the linear motor 8, adjusts the supply voltage to the linear motor 8, and The position is feedback controlled.

  The position counter 34 receives an A-phase signal and a B-phase signal having a phase difference of 90 degrees from the position encoder 8b of the linear motor 8, and outputs a position signal indicating the position of the linear motor 8 as digital data. The position counter 34 is reset by an origin reset signal from the position encoder 8b.

  The timing decoder 35 receives the position data from the position counter 34 and outputs an LD ON timing signal (160 μm pitch). In response to the rising edge of this signal, the one-shot multivibrator (MS) 46 outputs a 2 ms wide LD on pulse to the laser diode driver 36 and turns on the laser diode 1 in pulses. The laser diode 1 incorporates a light amount monitor photodiode (not shown), whereby the light amount of the laser diode 1 is controlled to be constant.

  Since the linear motor 8 is moving even while the LD is on, the correction is made to shift the line light position depending on the moving direction, and the half pitch (80 μm in the embodiment) is shifted in the reverse direction to the forward direction. Therefore, the forward / reverse direction signal is input from the linear motor drive command device 31 as described above.

  The position latch 37 latches the position data output from the position counter 34 at the rising edge of the LD on timing, and the position in the Y direction of the line light at that time is synchronized with the falling timing of the LD on pulse from the MS 46. To tell. Even when the LD is on, the line light moves and causes a deviation from the actual line light position. This is corrected in the CPU 44 by the line light moving speed, the LD on time, and the forward / reverse signal. Yes.

  On the other hand, the synchronization signal timing generator 39 receives the CCD camera synchronization timing signal from the timing decoder 35 via the OR circuit 35 ', and outputs a VD vertical synchronization signal that is synchronized with the HD horizontal synchronization signal. In association with the VD vertical synchronization signal, reading of the light amount data of each pixel in the previous frame is started. At the same time, accumulation of light quantity at each pixel starts, and an image by the line light 9 is acquired on the CCD area image sensor 38 of the CCD camera 6.

  The image on the CCD area image sensor 38 is read as a light amount value (analog value) of each pixel via the driver 33 by a vertical register transfer clock, a horizontal register transfer clock, etc. from the synchronization signal timing generator 39. This is input to the A / D converter 48 via the amplifier 47 and input to the V-RAM image memory 40 as digital data.

  The horizontal address counter 42 is reset after a predetermined number of horizontal clocks from the falling edge of the horizontal synchronizing signal from the synchronizing signal timing generator 39, and then the horizontal position of the current pixel in the effective screen is counted by counting the horizontal clocks thereafter. (Horizontal address) is output. The horizontal address value is input to the horizontal address of the V-RAM image memory 40 via the multiplexer 41.

  On the other hand, the vertical address counter 43 is reset after a predetermined number of horizontal synchronization signals from the falling edge of the vertical synchronization signal from the synchronization signal timing generator 39, and then counts the pulses of the horizontal synchronization signal, thereby counting the number of horizontal synchronization signals. The vertical position (vertical address) of the current pixel is output. This vertical address value is input to the vertical address of the V-RAM image memory 40 via the multiplexer 45.

  The write timing generator 49 writes a write signal to the V-RAM image memory 40 in synchronization with the horizontal clock between the effective horizontal scanning section signal from the horizontal address counter 42 and the effective vertical scanning section signal from the vertical address counter 43. Is output. Thus, the V-RAM image memory 40 stores each pixel data in the effective screen determined by the effective horizontal scanning section signal and the effective vertical scanning section signal.

  The horizontal / vertical address generator 50 outputs a horizontal address signal to the multiplexer 41, a vertical address signal to the multiplexer 45, and a read signal to the V-RAM image memory 40. The multiplexers 41 and 45 are switched to the reading side in response to the switching signal from the CPU 44, and the image data in the V-RAM image memory 40 having addresses determined by the horizontal address signal and the vertical address signal are sequentially read in synchronization with the reading signal. The reading of the image data is performed after the writing of the image data to the V-RAM image memory 40 is completed. This is ensured by switching the multiplexers 41 and 45 from the writing mode to the reading mode by the switching signal from the CPU 44.

[Circuit configuration (data processing)]
4 shows a circuit configuration for processing the image data stored in the V-RAM image memory 40. The circuit configuration centered on the V-RAM image memory 40 is that shown in FIG. The same is shown.

  Image data read from the V-RAM image memory 40 in synchronization with the read signal when the multiplexers 41 and 45 are switched to read by the switching signal is input to the gradation data filter processing block 60 and noise is removed. . The gradation data filter processing block 60 is provided with two one-line buffers 61 and 62, whereby image data for three lines can be obtained simultaneously. The image data for these three lines is input to the arithmetic circuit 63, the flatness F of the image data is calculated, and also input to the arithmetic circuit 64, and the maximum gradation value MAX and the minimum gradation value MIN. The difference ΔB is calculated. The image data for three lines is also input to the band elimination filter 68, where the band elimination filter is applied. The output of the 1-line buffer 61 is input to the delay circuit 69, and a delay corresponding to the calculation processing time is applied. Note that the processing of the arithmetic circuits 63 and 64 and the band elimination filter 68 is performed in units of 3 × 3 pixel blocks.

  The arithmetic circuit 65 calculates the ratio of the flatness F of the image data to the difference ΔB, and the comparator 66 compares the calculation result with a threshold value 66 '. If it is less than the threshold value, the multiplexer 68 selects the image data that has been subjected to the band removal filter processing by the band removal filter 68, and if it is greater than or equal to the threshold value, the delay circuit 69 applies a delay corresponding to each computation time. The selected image data is selected and output to the binarization processing block 70.

  In the binarization processing block 70, the average value calculation circuit 71 calculates an average value x (with a bar above) for each line of the image data from the gradation data filter processing block 60, and a standard deviation calculation circuit. 72, the standard deviation ρ is calculated for each line, and the threshold value calculation circuit 74 calculates the threshold value (x + 1.5ρ). The comparator 75 compares this threshold value with the image data for one line held in the one line buffer 73, and binarizes the image data.

  The binarized image data from the binarization processing block 70 is input to the noise removal processing circuit 83 and the two one-line buffers 81 and 82 of the binarization data filter processing block 80. The noise removal filter processing circuit 83 receives three lines of image data simultaneously from the two one-line buffers 81 and 82 on the input side and the direct image data, and small protrusions and isolated data are generated for each 3 × 3 image block. If it exists, if it exists, the process which removes the data is performed. The output of the noise removal processing circuit 83 is input to the determination circuit 87 and the 1-line buffer 85. The determination circuit 87 determines whether all of one line is 0. If all the one lines are 0, the multiplexer 89 selects the output of the OR circuit 88, and otherwise, selects the output of the 1 line buffer 85. Is input to the 1-line buffer 86. The image data in the 1-line buffer 85 corresponds to the current image data, and the output from the noise removal processing circuit 83 and the image data in the 1-line buffer 86 correspond to the image data before and after that. The image data filled in by OR processing of the data at the same horizontal position of the preceding and following lines is output.

  The binarized image data from the binarized data filter processing block 80 is input to the centroid position calculation processing block 90, and the centroid position is calculated for each line. The rising edge detection circuit 91 of the center-of-gravity position calculation processing block 90 detects that the binarized image data changes from “0” to “1”, and the horizontal address value of the horizontal address counter 93 at that time is latch circuit 94. Latch on. The falling edge detection circuit 92 detects that the binarized image data changes from “1” to “0”, and latches the horizontal address value of the horizontal address counter 93 at that time in the latch circuit 95. The barycentric position calculation circuit 96 calculates the barycentric position by averaging the horizontal address values at the time of rising and falling, and stores the value in the barycentric position calculation result memory 100. The horizontal address counter 93 counts a horizontal clock for reading from the V-RAM image memory in order to obtain a horizontal address value. The horizontal address counter 93 is reset when the image data 1 line is switched.

[Measurement of height data]
Next, the processing for obtaining the height data of the wiring board or cream solder will be described with reference to the flow of FIG. 5 and FIG. 6 by taking cream solder printed on the wiring board as an example in such a configuration.

  Generally, when measuring the height of cream solder, the brightness of the image of the resist surface between cream solders is extremely low compared to the brightness of the image of the cream solder, and the line light image of the resist surface cannot be recognized. Therefore, there is a problem that it is impossible to obtain the printing standard for cream solder. If the light intensity is increased or the exposure time is increased, the image on the resist surface can be recognized. However, this time, the image of the cream solder part causes halation, and the center of gravity calculation cannot be processed accurately. Therefore, height measurement is performed using two reference lines as described below.

  First, the CPU 44 generates a position command signal and a start signal in the linear motor drive command device 31, and moves the linear motor 8 to the first reference position (registration position of the wiring board) (step S11). When the first reference position is reached, the CPU 44 sends a CCD camera synchronization timing pulse through the OR circuit 35 '(step S12) and generates an LD ON signal to light the laser diode 1 for 30 ms, for example (step S13). .

  The laser light emitted from the laser diode 1 is condensed by the collimator lens 2, becomes a parallel light beam 1 a parallel to the optical center axis, and is narrowed down to become spot light by the focus lens 3. The laser spot light is reflected by the light projecting mirror 4 in a direction of 45 degrees with respect to the incident angle, and enters the line generator lens 5. The laser spot light is stretched in one direction (X direction) by the lens 5 by the lens 5 and becomes line light 9 having a width of 14 μm and a length of 10 mm on the object to be measured 11. This line light is imaged by a non-interlaced CCD camera 6 with a visual field of 6.4 mm × 4.8 mm.

  After waiting for time T1 in step S14, a CCD camera synchronization timing pulse is sent in step S15, and the synchronization signal timing generator 39 is driven to output the image data of the image sensor 38 of the CCD camera 6 to the output of the write timing generator 49. In synchronism with this, the data is read into the V-RAM image memory 40 (step S16). In this way, the acquired image data is shown in FIG. 7 as the first reference line 110.

  This image data is subjected to each image processing in step S17. First, the multiplexers 41 and 45 are switched to the read mode by the switching signal of the CPU 44, and the image data is read from the V-RAM image memory 40 in synchronization with the horizontal address and the vertical address according to the read signal from the horizontal / vertical address generator 50. .

  The read image data is subjected to gradation data filter processing in a gradation data filter processing block 60. The arithmetic circuit 63 calculates the flatness F of gradations around the pixel at the center of each 3 × 3 pixel block as the target pixel. The flatness F is obtained as an average value of absolute values of differences between pixels around the target pixel, and pixel columns are A, B, C,..., Pixel rows are 1, 2, 3,. For example, if the pixel of interest is B2,

を算出することにより平坦度Ｆが演算される。演算回路６４は、各３×３の画素ブロックの画素の最大値と階調の最小値の差ΔＢを求め、演算回路６５はＦ／ΔＢを演算する。比較器６６はＦ／ΔＢがしきい値６６’より小さいときには、画像データが平坦でないので、マルチプレクサ６７を切り替える。これにより帯域除去フィルタ回路６８で注目画素に対して

The flatness F is calculated by calculating. The arithmetic circuit 64 calculates a difference ΔB between the maximum pixel value and the minimum gradation value of each 3 × 3 pixel block, and the arithmetic circuit 65 calculates F / ΔB. When F / ΔB is smaller than the threshold value 66 ′, the comparator 66 switches the multiplexer 67 because the image data is not flat. As a result, the band elimination filter circuit 68 applies to the target pixel.

の帯域除去フィルタ処理のかけられたデータが出力され、一方ΔＢ＝０の時またはＦ／ΔＢがしきい値より大きい時は遅延回路６９からのデータが選択され、帯域除去フィルタ処理されないデータが出力される。

On the other hand, when ΔB = 0 or when F / ΔB is larger than the threshold value, the data from the delay circuit 69 is selected, and the data not subjected to the band removal filter processing is output. Is done.

  The image data on which the gradation data has been filtered in this way is binarized by the binarization processing block 70. For this purpose, the arithmetic circuits 71 and 72 calculate the average value x and the standard deviation ρ of the gradation of each line. The comparator 75 sets the current pixel value to 1 when the gradation data of each pixel of the line buffer 73 is larger than the average value x + ρ × 1.5 of the gradation of the line, and when Will binarize the current pixel value to 0.

  Each of the binarized image data is sent to the binarized data filter processing block 80, and the noise removal processing circuit 83 removes the small protrusion data and the isolated data as noise for each 3 × 3 pixel block. This noise removal corresponds to performing the filter processes a to f as shown in FIG. With the 3 × 3 center pixel as the target pixel, when the pattern of FIG. 8 appears, the value of the target pixel is set to zero. The five types of filters other than f are rotated by 90 degrees and executed. The binarized image data subjected to noise processing in this way is sent to the 1-line buffers 85 and 86. When all the pixels in one line are 0, the determination circuit 87 performs hole filling with reference to the preceding and following lines. For example, if all the pixels in the second line are 0, and there is 1 pixel in the preceding and succeeding lines (first and third lines), the place where the 1 pixel exists is set to 1.

  The image data processed in this way is sent to the centroid position calculation processing block 90, and the centroid position (average value) is calculated by the calculation circuit 96. As shown in FIG. 13, the center of gravity is determined by assigning sequential numbers such as 1, 2, 3,... To the pixel columns A, B, C. In this example, for the first and second rows, the pixel values in the I and J columns are 1, the I column number is 9, and the J column number is 10. Therefore, the centroid values in the first and second rows are 9. 5 For the third, fourth, and fifth rows, the pixels in the I, H, and G columns are 1, and the center-of-gravity value of each row is 9, 8, and 7, which is the same value as the number assigned to each column. In the same manner, the center of gravity value of each row is obtained.

  When the graph is drawn with the vertical axis as the center of gravity and the horizontal axis as the line number in this way, the graph is as shown in FIG. This result is stored in the memory 100 as height data of the first reference position (registration position) in step S18.

  Since the height data of the first reference position is obtained in this way, the line light is projected to the second reference position where the cream solder is to be printed next, and the height data of the surface is measured. . Therefore, in step S21, the linear motor 8 is linearly moved to the second reference position in the Y direction at a constant speed of 4.8 mm / sec (moving by 2.72 mm) according to the control signal, and is coupled to the shaft of the linear motor 8 accordingly. The light projecting unit 7 also moves linearly in the Y direction parallel to the parallel light beam 1a. The light projecting unit 7 moves in the front-rear direction toward the parallel light beam, but the focus lens 3 always receives the parallel light beam 1a, and therefore does not affect the imaging function of the focus lens 3.

  The next steps S22 to S27 are the same as steps S12 to S17. The captured image data is indicated by 111 in FIG. 7, and the calculated height data is indicated in FIG. 9B. This result is stored in the memory 100 as the height data of the second reference position in step S28. Next, in step S29, a difference Δx between the average height data between the first reference line and the second reference line is calculated. In the example of FIG. 9, Δx = 171 μm-127 μm = 44 μm.

  As described above, two line lights are projected onto the wiring board and the parallelism of the measurement surface is measured. Next, cream solder is printed on the wiring board. If it is confirmed in step S30 in FIG. 6 that cream solder is printed, the linear motor 8 is moved to the first reference position (position 110 in FIG. 7), that is, the registration position in step S31. Steps S31 to S38 are the same as steps S11 to S18. An image of the line light projected at the first reference position is indicated by 112 in FIG.

  Subsequently, in step S41, the linear motor 8 is moved by 2.72 mm to move to the portion (second reference position) where the cream solder is printed. Subsequent steps S42 to S47 are the same as steps S32 to S37, except that the laser diode is lit in an exposure amount (exposure for 2 ms) suitable for cream solder in step S43. The image of this line light becomes an image as shown by 113a and 113b in FIG. In this case, the high-luminance image protruding to the right is the cream solder portion 113a, and the low-brightness linear portion therebetween is the resist surface or pad surface 113b of the wiring board.

  The gravity center position calculated in step S47, that is, the height data of the cream solder is as shown in FIG. 11, and this height data is stored in the memory 100 in step S48. This height data is processed assuming that the height of the first reference position is “0”. However, actually, the height of the resist surface set to “0” is not the resist surface on which cream solder is printed. Accordingly, the difference Δx (44 μm) in height data between the first reference line and the second reference line obtained in step S29 corresponding to the difference in height between the two resist surfaces corresponds to the difference in height between the two resist surfaces. The height of the cream solder portion is corrected (step S49). This is illustrated in FIG. 12, where the average height of the cream solder is 103 μm.

  Since the average height of the cream solder measured with another measuring instrument in advance was 102 μm, it was confirmed that the cream solder portion had an accurate height by the above method. At the time of acquiring the parallelism and the height of the cream solder part, the interval of each line light was made equal to 2.72 mm. This is for convenience of explanation, and the parallelism is calculated by performing linear approximation. If the position and interval are known, light can be projected and calculated at an arbitrary position and interval.

  As described above, in the above method, the height of the cream solder is measured based on the resist surface on which the cream solder is printed and another resist surface. The height of the cream solder is measured with correction. In this case, line light can be projected at an exposure amount suitable for the resist surface and the cream solder, respectively, and a clear resist surface and a light-cut image of the cream solder can be obtained. Is possible.

  In the example described above, the resist surface and the cream solder portion were imaged with different exposure amounts by changing the line light projection time, but the line light intensity or the CCD camera imaging sensitivity was changed. By doing so, you may make it image by the exposure amount suitable for each.

[Measurement of height data using spreadsheet software]
In the above-described embodiment, the image data in the V-RAM image memory 40 has been subjected to image processing with the circuit configuration shown in FIG. 4, but the image data in the V-RAM image memory 40 is taken into the spreadsheet software. You can also. Since the image data in the V-RAM image memory 40 is a bitmap image of 640 pixels wide × 480 pixels high, after each pixel is converted to gradation data of 256 gradations, a cell of 640 columns × 480 rows is obtained. Into the spreadsheet software. Since the resolution between the pixels is 10 μm, the pixel corresponds to the cell when read into the spreadsheet software, and the pitch between the cells is 10 μm. However, since the actual spreadsheet software has a functional restriction that the maximum number of columns is 256 columns, processing is performed by fetching gradation data of 200 columns × 480 rows.

  First, the acquired gradation data is extracted for each 3 × 3 cell, and the filter processing is performed by checking the flatness of the gradation. The center cell of the 3 × 3 cells is set as the target cell, and the flatness of the gradation around the cell is calculated. An average value of absolute values of differences between cells around the target cell is obtained. .., The rows are 1, 2, 3,..., For example, the target cell is B2, and the flatness F is calculated according to Equation 1 (by the arithmetic circuit 63 in FIG. 4). Corresponding to calculation). Next, a ratio to the difference ΔB between the maximum gradation value and the minimum gradation value in the 3 × 3 cell is obtained (corresponding to the arithmetic circuit 65), and when F / ΔB is smaller than the threshold value (comparator 66). 2), the band elimination filter (corresponding to the filter circuit 68) of Formula 2 is applied to the target cell. If ΔB = 0 or F / ΔB is larger than the threshold value, nothing is done. Next, the target cell is moved to B3, the above processing is executed, and B4, B5,... Are processed. Then, the process proceeds to the next line, and processing is sequentially performed as C2, C3.

  When the gradation data filtering process is completed as described above, the process proceeds to the next binarization process. The average value and standard deviation of the gradation of each row are calculated (corresponding to the arithmetic circuits 71 and 72). For each cell, when the gradation data of the cell is larger than the average value of the gradation of the row + 1.5 × standard deviation (corresponding to the comparator 75), the value of the current cell is rewritten to 1, and at the following times Erases the value of the current cell. The average value and standard deviation of the first row are used for the cells A1, B1, C1,..., And the average value and standard deviation of the second row are used for the cells A2, B2, C2,. Each cell is 1 or blank.

  After the values of the respective cells are binarized in this way, the small protrusion data and the isolated data are considered to be noise. Therefore, these data are erased to remove noise. That is, the filter processes a to f as shown in FIG. 8 are performed. With the 3 × 3 center cell as the target cell, when the pattern of FIG. 8 appears, the value of the target cell is erased. The five types of filters other than f are rotated by 90 degrees (corresponding to the noise removal processing circuit 83).

  Next, reference is made to each row, and if all are blank, reference is made to an array of cells with a numerical value of 1 in the upper and lower rows, and hole filling is performed (corresponding to the determination circuit 87). Next, a centroid value is calculated for a cell of value 1 in each row. As shown in FIG. 13, for columns A, B, C..., This number becomes the value of the center of gravity when serial numbers 1, 2, 3,. Corresponding to circuit 96). In this example, for the first and second rows, the cell values in the I and J columns are 1, the I column number is 9, and the J column number is 10. Therefore, the centroid values in the first and second rows are 9. 5 For the third, fourth, and fifth rows, the cells in the I, H, and G columns are 1, and the center-of-gravity value of each row is 9, 8, and 7, which is the same value as the number assigned to each column. In the same manner, the center of gravity value of each row is obtained.

  Thus, each processing block 60, 70, 80, 90 of FIG. 4 can also be processed by software.

It is a perspective view which shows the structure of the height measuring apparatus used for this invention. It is a side view of the height measuring apparatus of FIG. It is the circuit diagram which showed the circuit structure which acquires image data from the image obtained by projecting line light. It is the circuit diagram which showed the circuit structure which processes the acquired image data. It is the flowchart figure which showed the flow of the process of the image obtained when two line lights are projected before printing cream solder. It is the flowchart figure which showed the flow of the process of the image obtained when two line lights are projected after printing cream solder. It is explanatory drawing which showed the image obtained when two line lights are projected before printing cream solder. It is explanatory drawing which shows the filter data used for the filter process of image data. It is a diagram which shows the height of the flat part calculated | required from the image data obtained when two line lights are projected before printing cream solder. It is explanatory drawing which showed the image obtained when two line lights are projected after printing cream solder. It is a diagram which shows the height of the cream solder calculated | required from the image data of the cream solder part. It is a diagram which shows the height data of the corrected cream solder. It is explanatory drawing which showed the example for calculating | requiring a gravity center value from the information of a pixel or a cell. It is the perspective view which showed the structure of the conventional three-dimensional measuring apparatus.

Explanation of symbols

1 Laser light source 5 Line generator 6 CCD camera 9 Line light

Claims (3)

In the height data processing method of processing the height data of the protrusion obtained by imaging the protrusion cut by the line light and obtained by the light cutting method,
The image of the protrusion is taken out as gradation data for each pixel,
Check the flatness of the gradation of the surrounding pixels for each pixel,
If it is not flat, perform gradation processing to filter the target pixel,
A height data processing method comprising: binarizing the gradation data subjected to the gradation processing and converting an image of a protruding object into binary data.   The average value and standard deviation of the filtered gradation data is obtained for each row, and the threshold value determined from the average value and the standard deviation for each row is compared with the gradation data of each pixel in the row. 2. The height data processing method according to claim 1, wherein each pixel is binarized. In the height data processing method of processing the height data of the protrusion obtained by imaging the protrusion cut by the line light and obtained by the light cutting method,
The image of the protrusion is taken out as binary data of pixels arranged in rows and columns,
Filter the binarized data,
A height data processing method comprising embedding data in a blank line in accordance with an array of binarized data in the preceding and succeeding lines when a filter process results in a blank line.

Images