JP6229134B2 - Measuring device - Google Patents

Description

  The present invention relates to a measuring device.

  2. Description of the Related Art Conventionally, an apparatus for measuring a three-dimensional shape of an object to be measured using a light cutting method is known. For example, Patent Document 1 describes a three-dimensional shape measurement system that derives the position of each part of a measurement object in a three-dimensional coordinate system and measures the three-dimensional shape of the measurement object based on each derived position. Yes. Patent Document 2 describes an optical cutting three-dimensional measuring apparatus that can determine the relative heights of a plurality of positions of interest in a measurement object.

JP 2008-26243 A JP 2008-292434 A

  The prior art has a problem that it is easily affected by noise.

The measurement apparatus according to claim 1, wherein the object to be measured is irradiated with slit light from a predetermined irradiation direction, and the object to be measured that has been irradiated with the slit light is irradiated with the irradiation object. An imaging unit for imaging from a predetermined imaging direction different from the direction and outputting an imaging signal; a measurement signal generating unit for generating a measurement signal based on the imaging signal; and a luminance distribution model of the measurement signal and the predetermined slit light Correlation calculating means for performing a correlation calculation between, and a specifying means for specifying an irradiation range of the slit light in the measurement signal based on a result of the correlation calculation by the correlation calculating means, and the object to be measured, said irradiating means and said imaging means, the relative positional relationship, and a settable positional relationship setting means of the positional relationship different street from each other, said imaging means, said plurality Street The measurement object is imaged in a state in which each of the positional relationships is set, and the measurement signal creating means applies the measurement object to each of the plurality of imaging signals corresponding to each of the plurality of positional relationships. by extracting a signal representative of the luminance of the set target point, it characterized that you generate the measurement signal.
The measuring apparatus according to claim 3, wherein the object to be measured is irradiated with slit light from a predetermined irradiation direction, and the object to be measured that has been irradiated with the slit light is irradiated with the irradiation object. An imaging unit for imaging from a predetermined imaging direction different from the direction and outputting an imaging signal; a measurement signal generating unit for generating a measurement signal based on the imaging signal; and a luminance distribution model of the measurement signal and the predetermined slit light Correlation calculating means for performing a correlation calculation between, and a specifying means for specifying an irradiation range of the slit light in the measurement signal based on a result of the correlation calculation by the correlation calculating means, and the object to be measured, A positional relationship setting unit capable of setting a relative positional relationship between the irradiation unit and the imaging unit to a plurality of different positional relationships, and the imaging unit includes the plurality of types The measurement object is imaged in a state in which each of the positional relationships is set, and the measurement signal creating unit is configured to extract the imaging signal corresponding to each of the plurality of positional relationships from the imaging signal. A signal representing luminance along the short direction of the slit light is extracted, and a signal representing the luminance of a plurality of attention points set along the short direction is extracted from each of the plurality of extracted signals representing the luminance. Are extracted as a plurality of the measurement signals.
The measuring apparatus according to claim 4, wherein the object to be measured is irradiated with slit light from a predetermined irradiation direction, and the object to be measured that has been irradiated with the slit light by the irradiation means An imaging unit for imaging from a predetermined imaging direction different from the direction and outputting an imaging signal; a measurement signal generating unit for generating a measurement signal based on the imaging signal; and a luminance distribution model of the measurement signal and the predetermined slit light Correlation calculating means for performing a correlation calculation between, and a specifying means for specifying an irradiation range of the slit light in the measurement signal based on a result of the correlation calculation by the correlation calculating means, and the object to be measured, A positional relationship setting unit capable of setting a relative positional relationship between the irradiation unit and the imaging unit to a plurality of different positional relationships, and the imaging unit includes the plurality of types The measurement object is imaged in a state where each of the positional relationships is set, and the measurement signal generating means is a group of the imaging signals selected from the plurality of imaging signals corresponding to the plurality of positional relationships. The process of generating a plurality of measurement signals based on the above is repeatedly executed for the group of imaging signals of different combinations.
The measurement apparatus according to claim 7, wherein the object to be measured is irradiated with slit light from a predetermined irradiation direction, and the object to be measured which has been irradiated with the slit light is irradiated with the irradiation object. An imaging unit for imaging from a predetermined imaging direction different from the direction and outputting an imaging signal; a measurement signal generating unit for generating a measurement signal based on the imaging signal; and a luminance distribution model of the measurement signal and the predetermined slit light A correlation calculation means for performing a correlation calculation with the correlation calculation means, a specification means for specifying an irradiation range of the slit light in the measurement signal based on a result of the correlation calculation by the correlation calculation means, and a specification by the specification means By calculating the projection of the measurement signal corresponding to the irradiation range of the slit light and a predetermined orthogonal base, the center position of the slit light in the measurement signal is calculated. And the center position calculation means for calculation, characterized in that it comprises a.

  According to the present invention, it is possible to provide a measuring apparatus that is less affected by noise.

It is a perspective view showing typically the composition of three-dimensional measuring device 1 concerning a 1st embodiment of the present invention. 3 is a block diagram schematically showing the configuration of a control unit 40. FIG. 3 is a schematic diagram illustrating an example of an image captured by an imaging unit 30. FIG. It is a figure which shows the example of the measurement signal produced by the measurement signal production part 41. FIG. It is a figure which shows an example of the luminance distribution model 46 of the slit light 50. FIG. It is a figure which shows the calculation by the center position calculating part 44 typically. It is a figure which shows typically the measuring method of the three-dimensional shape by the shape measurement part 45. FIG. It is a flowchart of the three-dimensional measurement process which the control part 40 performs. 3 is a schematic diagram illustrating an example of an image captured by an imaging unit 30. FIG.

(First embodiment)
Hereinafter, the three-dimensional measuring apparatus according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1A and FIG. 1B are perspective views schematically showing the configuration of the three-dimensional measuring apparatus 1 according to the first embodiment of the present invention. FIG. 1A and FIG. 1B are perspective views of the same three-dimensional measuring apparatus 1 as seen from different viewpoints, and a three-dimensional coordinate system composed of an X axis, a Y axis, and a Z axis is set. Yes. The three-dimensional measuring device 1 is a device that measures the three-dimensional shape of the measurement object 2. The three-dimensional measurement apparatus 1 includes a transport unit 10, a light source unit 20, an imaging unit 30, and a control unit 40.

  The transport unit 10 has a placement surface 11 parallel to the XY plane. The transport unit 10 transports the measurement object 2 placed on the placement surface 11 at a constant speed v in the transport direction O parallel to the Y axis. The light source unit 20 is, for example, a slit laser light source. The light source unit 20 is provided above the placement surface 11 (+ Z direction). The light source unit 20 irradiates the mounting surface 11 with the slit light 50 toward the −Z direction. The object to be measured 2 passes through the slit light 50 irradiated by the light source unit 20 in the process of being transported by the transport unit 10. The slit light 50 is thin sheet-like light. The slit light 50 is at least larger than the measurement object 2 and has a uniform light amount spread S in the longitudinal direction (direction parallel to the X axis) perpendicular to the transport direction O. On the other hand, the slit light 50 has only a minute spread D in the short direction parallel to the transport direction O (the direction parallel to the Y axis). Further, the light amount distribution of the slit light 50 in the short direction is a mountain. That is, the amount of light becomes the largest at a predetermined center position, and the amount of light decreases toward the bottom of the spread D. In FIG. 1, the expanse D in the short direction is exaggerated from the actual one for convenience of explanation. The slit light 50 is reflected from the surface of the object to be measured 2 to form a light cutting line 51.

  The imaging unit 30 is a digital camera provided with an imaging optical system and an imaging element. The imaging unit 30 is installed above the extension line in the transport direction O of the transport unit 10 (+ Z direction) with the imaging optical system facing the placement surface 11. The imaging unit 30 images the vicinity of the position irradiated with the slit light 50 from the diagonally upper side of the mounting surface 11 in the entire mounting surface 11. That is, the imaging unit 30 images the measurement object 2 irradiated with the slit light 50 from an imaging direction different from the irradiation direction in which the light source unit 20 irradiates the slit light 50. The imaging unit 30 outputs an imaging signal (hereinafter simply referred to as an image) to the control unit 40. The control unit 40 measures the surface shape of the measurement object 2 based on the image output from the imaging unit 30.

  In summary, the transport unit 10 sets the relative positional relationship between the measured object 2, the light source unit 20, and the imaging unit 30 to various positional relationships by transporting the measured object 2. The light source unit 20 irradiates the measurement object 2 with the slit light 50 from a predetermined irradiation direction. Then, the imaging unit 30 images the measurement object 2 in a state where the various positional relationships are set by the transport unit 10, and outputs an image corresponding to each of the various positional relationships to the control unit 40.

  FIG. 2 is a block diagram schematically showing the configuration of the control unit 40. The control unit 40 functionally includes a measurement signal creation unit 41, a correlation calculation unit 42, a range identification unit 43, a center position calculation unit 44, and a shape measurement unit 45. Each of these units is realized in software by the CPU included in the control unit 40 executing a predetermined control program stored in advance in a storage medium (not shown). Each of these units can be configured as an electronic circuit having an equivalent function.

  Hereinafter, each part which the control part 40 has is demonstrated in order.

(Description of measurement signal creation unit 41)
As schematically illustrated in FIG. 2, a plurality of images obtained by sequentially capturing the measurement object 2 being conveyed are sequentially input from the imaging unit 30 to the measurement signal creation unit 41. In FIG. 2, the images input to the control unit 40 are illustrated as images F1, F2,. The measurement signal creation unit 41 first selects the first n images F1 to Fn from among the input images F1 to F100 (n is an integer of 1 or more). Then, a measurement signal corresponding to the attention point set on the surface of the measurement object 2 is created from the selected n images. In the following description, it is assumed that n = 5. The point of interest is a virtual point set on the surface of the measurement object 2. The measurement signal creation unit 41 sets m attention points for one measurement object 2 (m is an integer of 1 or more). Therefore, the measurement signal creation unit 41 creates m measurement signals corresponding to each of the m attention points from the first five (n) images F1 to F5. The measurement signal creation unit 41 outputs the created m measurement signals to the correlation calculation unit 42.

  Next, the measurement signal creation unit 41 selects five (n) images F2 to F6 starting from the image F2 next to the image F1 among the input images F1 to F100. Then, m measurement signals are similarly generated from the selected five (n) images F <b> 2 to F <b> 6 and output to the correlation calculation unit 42. The measurement signal creation unit 41 repeats this process while shifting the images to be selected one by one, such as images F3 to F7, images F4 to F8,..., Images F96 to F100, and sets m measurement signals in a total of k sets. Are sequentially generated and output to the correlation calculation unit 42 (k is an integer of 1 or more).

  Next, a method in which the measurement signal creation unit 41 creates m measurement signals from five (n) images F1 to F5 will be described.

  FIG. 3 is a schematic diagram illustrating an example of an image captured by the imaging unit 30. FIG. 3 shows an image F1 imaged at time t1, an image F2 imaged at time t2 after time t1, an image F3 imaged at time t3 after time t2, and a time t4 after time t3. Five images are schematically shown: a captured image F4 and an image F5 captured at time t5 after time t4. The images F <b> 1 to F <b> 5 are images obtained by capturing the measurement object 2 being transported that is irradiated with the slit light 50.

  In the following description, the coordinates in the images F1 to F5 may be referred to. The coordinate systems of the images F1 to F5 are set such that the lower left corner is the origin (0, 0), the right direction is the + x direction, and the upper direction is the + y direction.

  Since the measurement object 2 is being transported when the images F1 to F100 are captured, the relative positional relationship between the measurement object 2 and the light source unit 20 and the imaging unit 30 at the time of imaging the images F1 to F100 is different. ing. The position and imaging direction (imaging angle) of the imaging unit 30, and the position of the light source unit 20 and the irradiation direction (irradiation angle) of the slit light 50 are fixed.

  FIG. 3 shows a partial image FP1 obtained by enlarging a part of the measurement object 2 in the entire image F1. Further, partial images FP2 to FP5 obtained by enlarging the same part as the partial image FP1 from the images F2 to F5 are also shown. Here, “the same part” means the same part of the DUT 2. Since the measurement object 2 is conveyed by the conveyance unit 10, the position of the partial image FP1 in the image F1 is different from the position of the partial image FP2 in the image F2.

  In order to simplify the description, it is assumed that the imaging unit 30 has a telecentric imaging optical system. Therefore, the size of the measurement object 2 reflected in the images F <b> 1 to F <b> 5 (the image height of the measurement object 2 imaged by the imaging optical system) does not depend on the distance between the measurement object 2 and the imaging unit 30. Always constant.

  While the conveyance unit 10 conveys the measurement object 2 at the conveyance speed v, the imaging unit 30 repeatedly images the measurement object 2 at a predetermined frame rate. Since the imaging unit 30 images the measurement object 2 from an extension line in the transport direction O, the measurement object 2 moves from the top to the bottom as time passes in the images F1 to F100. Since the conveyance speed v by the conveyance unit 10 is constant, the object to be measured 2 moves by ΔH pixels between images. Accordingly, in the image F2 captured next to the image F1, the DUT 2 has moved by ΔH pixels in the −y direction (downward) from the image F1. In the present embodiment, ΔH is 2. For example, when the coordinates of the upper left corner of the partial image FP1 are (x1, y1), the coordinates of the upper left corner of the partial image FP2 are (x1, y1-ΔH). Similarly, the coordinates of the upper left corner of the partial image FP3 are (x1, y1-2 × ΔH), the coordinates of the upper left corner of the partial image FP4 are (x1, y1-3 × ΔH), and the coordinates of the upper left corner of the partial image FP5 are (X1, y1-4 × ΔH).

  The measurement signal creation unit 41 sets a point of interest at the position of each pixel constituting the region corresponding to the measurement object 2 in the image F1. In FIG. 3, attention points P <b> 1 to P <b> 9 arranged in a line of x coordinate = x <b> 2 are illustrated as a part thereof. Now, of the attention points P1 to P9, attention is paid to a certain attention point P1 set in the partial image FP1. In the partial image FP2 of the image F2, the attention point P1 is present at the same position as the position of the attention point P1 in the partial image FP1 (the position of the partial image FP2 in the image F2 is downward from the partial image FP1 in the image F1). It is shifted by 2 pixels (ΔH pixels)). The measurement signal creation unit 41 sets the pixel of the attention point P1 set in the image F1, the pixel of the attention point P1 in the image F2, the pixel of the attention point P1 in the image F3, and the attention point P1 in the image F4. A pixel and a pixel at the point of interest P1 in the image F5 are extracted. And the measurement signal corresponding to the attention point P1 is created by arranging the luminance values of the pixels thus extracted in time series. In other words, the measurement signal is a signal that represents a change in luminance at the point of interest in the selected five (n) images.

  Similarly, the measurement signal creation unit 41 creates measurement signals from the images F1 to F5 for all attention points set based on the image F1. Thereby, m measurement signals (first set) corresponding to the images F <b> 1 to F <b> 5 are created and output to the correlation calculation unit 42. Similarly, the measurement signal creation unit 41 creates m measurement signals for each combination of the images F2 to F6, F3 to F7,..., F96 to F100, and outputs them to the correlation calculation unit 42. As described above, m measurement signals for k sets are output to the correlation calculation unit. Here, k is the number of combinations of five (n) images in the input images F1 to F100.

  FIG. 4 is a diagram illustrating an example of a measurement signal created by the measurement signal creation unit 41. The measurement signal SP3 is a measurement signal created for the attention point P3 shown in FIG. 3 based on the images F1 to F5. Similarly, measurement signals SP4, SP5, SP6, SP7, and SP8 are measurement signals created for the attention points P4, P5, P6, P7, and P8 shown in FIG. 3, respectively.

  The attention point P3 and the attention point P5 are located at a distance of 2 pixels (ΔH pixels) in the vertical direction of the image. Each attention point moves by 2 pixels (ΔH pixels) per frame in the vertical direction of the image. Accordingly, the coordinates of the attention point P3 in the image F2 coincide with the coordinates of the attention point P5 in the image F1. Further, the measurement signal SP5 corresponding to the attention point P5 has a shape obtained by shifting the measurement signal SP3 corresponding to the attention point P3 by one frame. The same applies to the measurement signal SP5 and the measurement signal SP7.

  The relationship between the attention point P4 and the attention point P6, and the relationship between the attention point P6 and the attention point P8 are the same. That is, the measurement signal SP6 has a shape obtained by shifting the measurement signal SP4 by one frame, and the measurement signal SP8 has a shape obtained by shifting the measurement signal SP6 by one frame. On the other hand, the coordinates of the attention point P4 located between the attention point P3 and the attention point P5 do not coincide with the coordinates of the attention point P3 and the coordinates of the attention point P5 in other frames. As illustrated in FIG. 4, the measurement signal SP4 corresponding to the target point P4 has a shape as if the measurement signal SP3 and the measurement signal SP5 are shifted by 0.5 frames (1 / ΔH frames). In other words, in this embodiment, the attention point set at a position where the remainder obtained by dividing the y coordinate by 2 (ΔH) becomes 0 and the attention point set at a position where the remainder becomes 1 are independent of each other. It can be said.

(Description of Correlation Calculation Unit 42)
The luminance value included in the measurement signal created for the point of interest P5 is the luminance value of the point of interest P5, which is the same point of the measurement object 2. Therefore, if the slit light 50 does not exist, and the conditions such as the noise of the image pickup device included in the image pickup unit 30 and the irradiation state of the ambient light are uniform, the measurement signal SP5 at the point of interest P5 becomes a flat signal. It should be.

  Actually, since the object 2 to be measured is irradiated with the slit light 50, when the slit light 50 is applied to the attention point P5, the luminance value of the attention point P5 increases. Further, as described above, since the slit light 50 has a mountain-like luminance distribution in the short direction, the luminance value becomes maximum when the center position of the slit light 50 coincides with the position of the point of interest P5. Accordingly, the position where the luminance value of the attention point P5 is maximized, that is, the peak position of the luminance value in the measurement signal SP5 of the attention point P5 is a position where the position of the attention point P5 and the center position of the slit light 50 coincide. It can be said.

  However, the luminance value may increase regardless of the center position of the slit light 50 due to the influence of disturbances such as noise due to reflection and electronic noise generated in the imaging device. For example, the measurement signal SP11 illustrated in FIG. 4 has a generally high luminance level due to the influence of ambient light or the like. Further, the measurement signal SP12 has an instantaneously large luminance value due to some noise. Therefore, simply examining the peak position of the luminance value in the measurement signal at the point of interest P5 may cause the position where the luminance value has increased due to noise or the like to be mistaken as the position coincident with the center position of the slit light 50. is there. The correlation calculation by the correlation calculation unit 42 is for discriminating a change in luminance value due to such disturbance and a change in luminance value due to the irradiation of the slit light 50.

  FIG. 5 is a diagram illustrating an example of the luminance distribution model 46 of the slit light 50. The luminance distribution model 46 is a model that represents the luminance distribution shape in the short direction of the slit light 50 (that is, in the X-axis direction in FIG. 1), and has a shape similar to the luminance distribution shape in the short direction of the slit light 50. Have. The luminance distribution model 46 shown in FIG. 4 is a luminance distribution composed of ten luminance values B (0) to B (9), where the vertical axis indicates the luminance value and the horizontal axis indicates the pixel position.

  In the present embodiment, the luminance distribution model 46 of the slit light 50 is set to a luminance value corresponding to 10 pixels selected as appropriate. However, the luminance distribution model 46 represents the luminance distribution of the slit light 50 in other modes. It may be a model. For example, it may be a function such as a sine function, a cosine function, or a Gaussian function, or may be a luminance value measured from the light amount of the slit light 50 irradiated to a predetermined test pattern. The width may be determined as appropriate based on the position of the light source unit 20, the characteristics of the irradiated slit light 50, the resolving power of the imaging unit 30, and the like. It is desirable that the luminance distribution model 46 of the slit light 50 has a shape that is as similar as possible to the luminance distribution shape in the short direction of the slit light 50.

  It is desirable that the luminance distribution model 46 subtracts the average value of all luminance values from each luminance value in advance so that the sum of the luminance values constituting the luminance distribution model 46 becomes zero. When such treatment is not performed, the correlation value is affected by the direct current component of the measurement signal, and the measurement signal having a generally high luminance value (for example, the measurement signal SP11 in FIG. 4) has a higher correlation than the measurement signal that is not so. The value is calculated. By performing the above-described procedure so that the sum of the brightness values of the brightness distribution model 46 is 0, it is possible to avoid the influence of the direct current component of the brightness value.

  The correlation calculation performed by the correlation calculation unit 42 is an operation in which the luminance distribution model 46 is applied to each part of the measurement signal and the correlation (similarity) with the shape of the luminance distribution model 46 in each part of the measurement signal is examined. That is, the calculated correlation value increases as the measurement signal has a shape close to the luminance distribution model 46.

  Hereinafter, a method in which the correlation calculation unit 42 calculates one correlation value corresponding to a certain measurement signal will be described.

  The correlation calculation unit 42 performs a correlation calculation between the five luminance values included in the measurement signal to be calculated and the luminance distribution model 46 as shown in the following equation (1), whereby the correlation value E (d) at each position is calculated. , S).

  In the above equation (1), A (d) to A (9 + d) are n luminance values constituting the measurement signal, and B (0) to B (9) constitute the luminance distribution model 46 of the slit light 50. 10 luminance values. D is the number of shifts (an integer greater than or equal to 0), and s is an integer greater than or equal to 0 representing a data number. As described above, the attention point set at a position where the remainder obtained by dividing the y coordinate by 2 (ΔH) becomes 0 and the attention point set at a position where the remainder becomes 1 are treated independently. The data number s is a number for realizing this independent handling, and is a remainder obtained by dividing the y coordinate by 2 (ΔH). That is, the data number s takes an integer of 0 to (ΔH−1) depending on the position of the attention point. Further, attention points with different data numbers s are also different in the position of the luminance distribution model 46 used for the correlation calculation. Specifically, B (0), B (2), B (4), B (6), and B (8) are used for the attention point whose data number s is 0, and the data number s is 1. B (1), B (3), B (5), B (7), and B (9) are used for the attention point. The reason for this is that, as described above, the measurement signal at the point of interest with the data number s 0 and the measurement signal at the point of interest 1 are shifted by 1/2 frame (1 / ΔH frame), respectively. Due to

  The correlation calculation unit 42 performs calculation according to the above equation (1), and calculates one correlation value E (d, s) corresponding to a certain measurement signal. The correlation calculation unit 42 performs the calculation according to the above equation (1) for each input measurement signal, and k × m correlation values E (d, s) corresponding to k × m measurement signals. Is output to the range specifying unit 43.

(Description of range specifying unit 43)
As schematically illustrated in FIG. 2, the range specifying unit 43 classifies the m attention points set for the images F1 to F5 based on the coordinates of the attention points in the image F1. Specifically, first, a plurality of groups of attention points having the same x coordinate are created. Then, the attention points included in each group are further classified into groups having the same data number s. In this embodiment, ΔH is 2, so that the y coordinate is divided into 0, 2, 4, 6,... And the y coordinate is 1, 3, 5, 7,. That is, m attention points set for the images F1 to F5 are classified into a group of attention points positioned every ΔH in the vertical direction. For example, the attention points P1 to P9 illustrated in FIG. 3 are classified into a group including the attention points P1, P3, P5, P7, and P9 and a group including the attention points P2, P4, P6, and P8.

  If ΔH is greater than 2, it is further classified into a plurality of groups. For example, if ΔH is 5, the y coordinate group is 0, 5, 10,..., 1, 6, 11,..., 2, 7, 12,. .. And a group of 4, 9, 14,...

  Next, for each group, the range specifying unit 43 specifies the target point having the highest correlation value E (d, s) as the irradiation range of the slit light 50 among the target points included in the group. In other words, the range specifying unit 43 specifies the position of the attention point having the highest correlation value E (d, s) in the images F <b> 1 to F <b> 5 as the irradiation range of the slit light 50. The range specifying unit 43 performs the same processing for each combination of the images F2 to F6, F3 to F7, ..., F96 to F100.

  Note that the irradiation range of the slit light 50 extends over a plurality of measurement signals in the same period. For example, the measurement signals SP3, SP5, and SP7 illustrated in FIG. 4 each include a high luminance value resulting from the irradiation of the slit light 50. This is because the measurement signal is a signal created from the imaging result in a certain period. That is, it is because a plurality of attention points pass through the irradiation range of the slit light 50 in the period of time t1 to t5. However, among these three measurement signals SP3, SP5 and SP7, the measurement signal SP5 whose overall signal shape is closest to the luminance distribution model 46 has the highest correlation value E (d, s). Therefore, the range specifying unit 43 specifies the point of interest P5 as the irradiation range of the slit light 50. In other words, in the present embodiment, the irradiation range of the slit light 50 refers to “a point of interest where the shape of the slit light 50 best appears in the measurement signal”.

(Description of the center position calculation unit 44)
The center position calculation unit 44 calculates the center position of the slit light 50 from the measurement signal corresponding to the attention point specified by the range specifying unit 43. That is, the center position calculation unit 44 calculates the timing (frame number) at which the target point and the center position of the slit light 50 substantially match each target point specified by the range specifying unit 43.

  For example, consider the measurement signal SP5 (FIG. 4) that is created from the images F1 to F5 and that corresponds to the point of interest P5. Now, it is assumed that the attention point P5 is specified by the range specifying unit 43. The measurement signal SP5 includes the luminance value of the attention point P5 at time t1, the luminance value of the attention point P5 at time t2, the luminance value of the attention point P5 at time t3, and the luminance value of the attention point P1 at time t4. It consists of the luminance value of the point of interest P1 at time t5. The center position calculation unit 44 calculates the center position of the slit light 50 in the measurement signal SP5, and at any time from the image capture time t1 of the image F1 to the image capture time t5 of the image F5, It is calculated whether the center position substantially matches.

  Next, specific calculation contents by the center position calculation unit 44 will be described. The center position calculation unit 44 applies the following equation (2) to the measurement signal SP5 of the selected point of interest P5 and calculates the phase φ (s).

  In the above equation (2), f (x, s) is each luminance value constituting the measurement signal SP5 (x is an integer of 0 to 4).

  The above equation (2) is an equation for calculating the projection of the cosine function and sine function, which are orthogonal bases, and the selected measurement signal SP5. The term “− (n−1) π / n” of the argument of the cosine function and the sine function is for adjusting so that the phase φ can be continuously obtained when the range of the arctangent function is −π to + π. Term. Further, the term “2π / (n × ΔH) × (s− (ΔH−1) / 2)” is a term for correcting the entire angle in accordance with the value of the data number s. The center position calculation unit 44 calculates the center position C of the slit light 50 in the measurement signal SP5 by applying the phase φ calculated by the above expression (2) to the following expression (3).

  The center position calculation unit 44 calculates the phase φ (s) and the center position C in the same manner for each attention point specified by the range specifying unit 43 for each group. Hereinafter, the meaning of the above formula (2) will be described.

  FIG. 6 is a diagram schematically illustrating the calculation performed by the center position calculation unit 44. The above equation (2) indicates that the luminance values f (0, s) to f (4, s) constituting one measurement signal are five vectors V1 to V1 having phases different from each other by 2π / 5 (that is, 72 degrees). This is an equation for obtaining the phase of a vector V6 that is considered as V5 and is the sum of the two. The magnitudes of the five vectors V1 to V5 are luminance values f (0, s) to f (4, s), respectively, and their phases are −4π / 5, −2π / 5, 0, + 2π / 5, and + 4π. / 5.

  As is apparent from FIG. 6, the DC components of the plurality of luminance values cancel out as vector components having different phases. Accordingly, even when the luminance value near the center of the slit light 50 is saturated (out-of-white), the phase φ (s) is accurately set without being dragged by the saturated luminance value. Can be sought.

  As described above, the y coordinate is set to 0, 2, and 5 based on the five consecutive images F1 to F5 by the measurement signal creation unit 41, the correlation calculation unit 42, the range specifying unit 43, and the center position calculation unit 44. From the groups 4, 6,..., The position of the optical cutting line 51 for one horizontal line (the center position of the slit light 50) is obtained. Similarly, the position of the light cutting line 51 for one horizontal line (the center position of the slit light 50) is obtained from the group having y coordinates of 1, 3, 5, 7,. That is, the position of the light cutting line 51 for two horizontal lines is calculated based on the five consecutive images F1 to F5. The measurement signal creating unit 41, the correlation calculating unit 42, the range specifying unit 43, and the center position calculating unit 44 are configured to display five consecutive images such as images F2 to F6, F3 to F7, F4 to F8,. Similar processing is performed for each combination. That is, in the present embodiment, the positions of the light cutting lines 51 for two lines (ΔH lines) per image frame can be obtained. As a result, the positions of a number of light cutting lines 51 formed on the surface of the measurement object 2 by the slit light 50 are obtained.

(Description of the shape measuring unit 45)
The shape measuring unit 45 obtains the three-dimensional shape of the measurement object 2 by arranging the positions of a large number of light cutting lines 51 calculated by the center position calculating unit 44 in the vertical direction. Specifically, based on the images F1 to F5, one horizontal line obtained from a group of y coordinates 0, 2, 4, 6,..., And based on the images F1 to F5, the y coordinate is 1,3. , 5, 7,..., One horizontal line obtained from a group of y coordinates 0, 2, 4, 6,... Based on the images F2 to F6,. By arranging them in the vertical direction in order, the three-dimensional shape of the measurement object 2 is obtained.

  FIG. 7 is a diagram schematically illustrating a three-dimensional shape measurement method by the shape measurement unit 45. When ΔH is 2, the attention point provided in each pixel of a certain image F is the attention point Pg with the y coordinate set at the position of 0, 2, 4,. The points of interest Ph are set at positions 5,. One center position C calculated by the center position calculation unit 44 based on a plurality of points of interest Pg included in a certain vertical line L1 for five (n) images starting from the image F is a surface shape 52. This corresponds to a certain point 53. A set of center positions C calculated on the basis of the attention point Pg for all the vertical lines L1, L2, L3,... Corresponds to one horizontal line 54 having the surface shape 52. Similarly, the set of center positions C calculated for all the vertical lines L1, L2, L3,... Based on the attention point Ph corresponds to one horizontal line 55 adjacent to the horizontal line 54 of the surface shape 52. ing.

  Finally, the shape measuring unit 45 arranges (ΔH × k) horizontal lines in the vertical direction and outputs the three-dimensional shape of the measurement object 2. If the number of images input from the imaging unit 30 is sufficiently large, k is approximately equal to the number of input images. For example, if 10,000 images are input, k becomes 9996, which is almost equal to 10,000. Therefore, it can be said that the shape measuring unit 45 generates the surface shape 52 composed of horizontal lines approximately (number of input images × ΔH).

  FIG. 8 is a flowchart of the three-dimensional measurement process executed by the control unit 40. The three-dimensional measurement process is a process for measuring the surface shape of the measurement object 2 based on the captured image. The three-dimensional measurement process is a process included in a control program executed by the control unit 40.

  First, in step S5, the measurement signal generation unit 41 stores one image input from the imaging unit 30 in a memory (not shown). In step S10, the measurement signal creation unit 41 determines whether five (n) images are stored in the left memory. If only five (n) images are stored in the memory, the measurement signal creation unit 41 proceeds with the process to step S5. On the other hand, if five (n) images are stored in the memory in step S10, the measurement signal creation unit 41 advances the process to step S20.

  In step S20, the measurement signal creation unit 41 sets m attention points using the earliest image (first image) among five images stored in a memory (not shown). In step S30, the measurement signal generation unit 41 extracts one luminance value from each of five images stored in a memory (not shown) for each target point, and arranges them in the order of image capturing times. Create a signal. That is, the measurement signal creation unit 41 creates m measurement signals corresponding to each of the m attention points.

  In step S <b> 40, the correlation calculation unit 42 performs a correlation calculation between the measurement signal and the luminance distribution model 46 of the slit light 50 for each of the m measurement signals. Thereby, m correlation values are calculated. In step S <b> 45, the range specifying unit 43 specifies two (ΔH) points of interest as the irradiation range of the slit light 50 for each of the vertical lines of the image. In step S50, the center position calculation unit 44 calculates the center position of the slit light 50 from the measurement signal for each identified point of interest. In step S60, the center position calculation unit 44 deletes the earliest image (the oldest image) out of five (n) images stored in a memory (not shown). In step S <b> 70, the shape measuring unit 45 determines whether or not the calculation has been completed for all image combinations. If the object to be measured 2 is not conveyed to the predetermined calculation completion position by the conveyance unit 10, the shape measurement unit 45 advances the process to step S5. On the other hand, when the object to be measured 2 has been transported to the predetermined calculation completion position by the transport unit 10, the shape measuring unit 45 advances the process to step S80. In step S80, the shape measuring unit 45 obtains the three-dimensional shape of the measurement object 2 as described with reference to FIG.

According to the three-dimensional measuring apparatus according to the first embodiment described above, the following operational effects can be obtained.
(1) The light source unit 20 (irradiation unit) irradiates the measurement object 2 with the slit light 50 from a predetermined irradiation direction. The imaging unit 30 captures the object to be measured 2 irradiated with the slit light 50 from the light source unit 20 from a predetermined imaging direction different from the irradiation direction, and outputs an image (imaging signal). The measurement signal creation unit 41 creates a measurement signal for each target point based on the image output by the imaging unit 30. The correlation calculation unit 42 performs a correlation calculation between each measurement signal and the luminance distribution model 46 of the predetermined slit light 50. The range specifying unit 43 (specifying means) specifies the irradiation range of the slit light 50 in the measurement signal based on the result of the correlation calculation by the correlation calculation unit 42. Since it did in this way, the measuring device with little influence of noise and disturbance light can be provided.

(2) The range specifying unit 43 specifies the range of the measurement signal having the maximum correlation value as the irradiation range of the slit light 50 as a result of the correlation calculation by the correlation calculation unit 42. Since it did in this way, the part where the luminance value is large by noise etc. and the part where the luminance value is large by projecting the slit light 50 can be discriminated accurately.

(3) The center position calculation unit 44 extracts a signal within the irradiation range of the slit light 50 specified by the range specifying unit 43 from the measurement signal, and calculates a projection between the extracted signal and a predetermined orthogonal base. The center position of the slit light 50 in the measurement signal is calculated. Since it did in this way, even if it is a case where the light quantity is saturated, the center position of the slit light 50 can be calculated | required correctly. In the method using an approximate curve, the measurement signal needs to include at least three luminance values. However, since the measurement signal is as described above, the measurement signal only needs to include at least one luminance value. That is, n can be made smaller than 3.

(4) The transport unit 10 (positional relationship setting unit) is configured to be able to set the relative positional relationship between the measurement object 2, the light source unit 20, and the imaging unit 30 to a plurality of different positional relationships. The imaging unit 30 images the measurement object 2 in a state where each of a plurality of positional relationships is set. Since it did in this way, the surface shape of the to-be-measured object 2 can be measured accurately.

(5) The measurement signal creation unit 41 extracts a measurement signal by extracting a signal representing the luminance of the target point set in the measurement object 2 from each of a plurality of images corresponding to each of a plurality of positional relationships. Generate. Since it did in this way, the part where the luminance value is large by noise etc. and the part where the luminance value is large by projecting the slit light 50 can be discriminated accurately.

(6) The measurement signal creation unit 41 sets a plurality of attention points each belonging to any of a plurality of groups in the short direction of the slit light 50, and performs a plurality of measurements corresponding to each of the plurality of attention points. Create a signal. The center position calculation unit 44 calculates, for each of the plurality of groups, the center position of the slit light in the measurement signal corresponding to one of the attention points belonging to the group. Since this is done, surface shape data for two horizontal lines (ΔH horizontal lines) per image frame can be calculated, and the resolution of the surface shape in the transport direction O can be increased. Alternatively, the conveyance speed of the object to be measured 2 can be increased without reducing the resolution of the surface shape with respect to the conveyance direction O.

(Second Embodiment)
Hereinafter, a three-dimensional measurement apparatus according to the second embodiment of the present invention will be described. In the following description, differences from the three-dimensional measurement apparatus 1 according to the first embodiment will be mainly described, and the same parts as those in the first embodiment are the same as those in the first embodiment. The same reference numerals are given and description thereof is omitted.

  The three-dimensional measurement apparatus 1 according to the first embodiment sets a plurality of attention points on the object 2 to be measured, and changes luminance (brightness distribution) between five (n) images for each attention point. A measurement signal is extracted and extracted, and the time when the slit light 50 is irradiated to the target point (the time when the position of the target point coincides with the center position of the slit light 50) is specified. The three-dimensional shape of was measured. On the other hand, the three-dimensional measuring apparatus according to the present embodiment measures the three-dimensional shape of the object to be measured 2 by specifying the range in which the slit light 50 is irradiated in each image. .

  In other words, the three-dimensional measurement apparatus 1 according to the first embodiment examines the object to be measured by examining the timing at which the target point matches the center position of the slit light 50 from a plurality of images for each target point. Two three-dimensional shapes were measured. On the other hand, the three-dimensional measuring apparatus of the present embodiment measures the three-dimensional shape of the measurement object 2 by examining the position of the measurement object 2 that matches the center position of the slit light 50 from one image. To do.

  Hereinafter, the three-dimensional measuring apparatus of the present embodiment will be described with reference to FIG. Similar to the first embodiment, a plurality of images obtained by imaging the measurement object 2 are input from the imaging unit 30 to the measurement signal creating unit 41. The measurement signal creation unit 41 of the present embodiment creates a measurement signal for each input image by extracting a luminance value along the vertical direction of the image (a direction parallel to the transport direction O). The correlation calculation unit 42 performs a correlation calculation between the created measurement signal and the luminance distribution model 46 of the slit light 50. The range specifying unit 43 specifies the irradiation range of the slit light 50 in the measurement signal based on the calculated correlation value. The center position calculation unit 44 calculates the center position of the slit light 50 in the vertical direction of the image based on the specified irradiation range. The shape measuring unit 45 obtains the three-dimensional shape of the measurement object 2 using a known triangulation method based on the center position of the slit light 50 for each image.

  FIG. 9 is a schematic diagram illustrating an example of an image captured by the imaging unit 30. FIG. 9 shows an image F1 similar to that shown in FIG. 3 and an image FP1 in which a part of the measurement object 2 is enlarged.

  First, the measurement signal creation unit 41 pays attention to pixels included in a certain vertical line L among all the pixels constituting the image F1. The measurement signal creation unit 41 sets the attention points P1, P2, P3, P4,... At the positions of all the pixels, and the luminance values of the attention points P1, P2, P3, P4,. To generate a measurement signal A ′ (x). That is, the measurement signal in the present embodiment is a signal obtained by extracting the luminance value of each pixel constituting the vertical line L. The correlation calculation unit 42 performs a correlation calculation on the measurement signal with the luminance distribution model 46 of the slit light 50 using the following equation (4).

  The correlation calculation unit 42 similarly calculates the correlation value E ′ (d) for all vertical lines other than the vertical line L.

  The range specifying unit 43 specifies the position (range) irradiated with the slit light 50 in the entire area of each vertical line from the correlation value E ′ (d) for each vertical line calculated by the correlation calculating unit 42. The center position calculation unit 44 calculates the projection of the luminance value and the orthogonal base by using the following equation (5) for the irradiation position (irradiation range) of the slit light 50 specified thereby, so that the slit light 50 Is accurately calculated, that is, the peak position of the luminance value.

  In the above equation (5), A ″ (x) is a signal obtained by extracting a range irradiated with the slit light 50 from the entire measurement signal A ′ (x). For example, in the measurement signals A ′ (0) to A ′ (N), when the range irradiated with the slit light 50 is A ′ (10) to A ′ (14), A ″ (0) = A ′ (10), A ″ (1) = A ′ (11),...

  Finally, the center position calculation unit 44 applies the phase φ ′ calculated by the equation (5) to the above equation (3), so that the center position of the slit light 50 in the vertical line L at the time of photographing the image F1. C is calculated. The center position calculation unit 44 performs the same calculation for all the vertical lines, and calculates the center position C of the slit light 50 in each vertical line.

  The measurement signal creation unit 41, the correlation calculation unit 42, the range specifying unit 43, and the center position calculation unit 44 perform the same processing for each of the images F2 to F5. Thereby, the center position C of the slit light 50 is calculated about all the vertical lines which comprise each of the images F1-F5. In other words, the position of the light cutting line 51 at each time point in time t1 to t5 is calculated. The position of the light cutting line 51 calculated at each time corresponds to the position of a part of the surface of the object 2 to be measured. The shape measuring unit 45 obtains the three-dimensional shape of the measurement object 2 from the position of the light cutting line 51 calculated for each image. Since such a three-dimensional shape measurement method is well known, detailed description thereof will be omitted.

According to the three-dimensional measuring apparatus according to the second embodiment described above, the following operational effects can be obtained.
(1) The measurement signal creation unit 41 extracts, for each of a plurality of images F1 to F5 corresponding to each of a plurality of positional relationships, a luminance value along the short direction of the slit light 50 from the image. A plurality of measurement signals corresponding to each of the plurality of images F1 to F5 are generated. Since it did in this way, unlike the three-dimensional measuring device 1 which concerns on 1st Embodiment, it becomes unnecessary to synchronize the conveyance speed of the conveyance part 10 and the imaging timing of the imaging part 30 (1st Embodiment). Then, it is necessary to synchronize the transport unit 10 and the imaging unit 30 so that the DUT 2 moves by ΔH pixels for each frame of the image). However, since the three-dimensional measuring apparatus according to the present embodiment can obtain only the position of the optical cutting line 51 for one line for each frame of the image, the resolution in the transport direction O is the third order of the first embodiment. It is inferior to the original measuring device.

  The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.

(Modification 1)
The imaging unit 30 may have an imaging optical system that is not telecentric. In this case, distortion corresponding to the distance from the imaging unit 30 occurs in the image captured by the imaging unit 30. Therefore, for example, a test chart in which ruled lines are drawn vertically and horizontally at regular intervals is imaged by the imaging unit 30, and characteristics relating to distortion are measured from the imaging result. Then, the distortion of the image output by the imaging unit 30 is corrected based on the measurement result and then input to the measurement signal generation unit 41, thereby obtaining the three-dimensional shape of the measurement object 2 as in the above-described embodiment. Can do.

(Modification 2)
The method for obtaining the center position of the slit light 50 may be different from the method using the projection with the orthogonal base described above (method using the formulas (2) and (5)). For example, an approximate expression of the brightness value may be created to calculate the peak of the brightness value, or the center of the brightness value may be used as the peak of the brightness value. However, when such a method is used, there is a possibility that the accuracy may be lowered when there is a portion where the luminance is saturated as compared with the method using the projection with the orthogonal base described above.

(Modification 3)
The positional relationship among the light source unit 20, the imaging unit 30, and the transport unit 10 may be different from that of the above-described embodiment. For example, the slit light 50 may be irradiated obliquely, and the imaging unit 30 may photograph the measurement object 2 from directly above. That is, you may arrange | position the imaging part 30 and the light source part 20 reversely. Further, the transport unit 10 may transport the light source unit 20 and the imaging unit 30 instead of the measurement object 2. That is, the transport unit 10 may change the relative positional relationship between the measurement object 2, the light source unit 20, and the imaging unit 30. As a method, the light source unit 20 and the imaging unit 30 may be moved even if the measurement object 2 is moved. You may move.

(Modification 4)
In the first embodiment, the feed width ΔH of the measurement object 2 between images is set to 2 pixels. However, the feed width ΔH may be larger than 2 if the spread D in the short direction of the slit light 50 is sufficiently large. In this way, the resolution in the direction along the transport direction O can be further increased.

(Modification 5)
The three-dimensional measurement apparatus 1 according to the first embodiment may be configured so that when measuring the surface shape of the measurement object 2, the texture information of the surface of the measurement object 2 is acquired at the same time. Specifically, the luminance values of the respective pixels included in the irradiation range of the slit light 50 specified by the range specifying unit 43 are sequentially integrated for the same pixel. The data obtained in this way can be handled as texture information on the surface of the measurement object 2. By doing so, it is possible to provide a more convenient measuring device that can not only simply measure the three-dimensional shape but also simultaneously acquire the texture information of the surface.

(Modification 6)
In the above-described first embodiment, correlation calculation or the like is performed using five consecutive images as one unit. The number of 5 is an example, and correlation calculation or the like can be performed on a smaller number of images or a larger number of images.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1 ... Three-dimensional measuring apparatus, 2 ... To-be-measured object, 10 ... Conveyance part, 20 ... Light source part, 30 ... Imaging part, 40 ... Control part, 41 ... Measurement signal creation part, 42 ... Correlation calculation part, 43 ... Range specification Part 44... Center position calculation part 45 45 shape measuring part

Claims (7)

Irradiation means for irradiating the measurement object with slit light from a predetermined irradiation direction;
Imaging means for imaging the measurement object irradiated with the slit light from the irradiation means from a predetermined imaging direction different from the irradiation direction, and outputting an imaging signal;
Measurement signal creating means for creating a measurement signal based on the imaging signal;
Correlation calculation means for performing a correlation calculation between the measurement signal and a predetermined luminance distribution model of the slit light;
Based on the result of the correlation calculation by the correlation calculation means, a specifying means for specifying an irradiation range of the slit light in the measurement signal;
A positional relationship setting unit capable of setting a relative positional relationship between the object to be measured, the irradiation unit, and the imaging unit to a plurality of different positional relationships ;
The imaging means images the object to be measured in a state where each of the plurality of positional relationships is set,
The measurement signal creating means extracts the signal representing the luminance of the point of interest set in the measurement object from each of the plurality of imaging signals corresponding to each of the plurality of positional relationships. measuring device characterized that you generate a signal. The measuring device according to claim 1 ,
Center position calculation for calculating the center position of the slit light in the measurement signal by calculating the projection of the measurement signal corresponding to the irradiation range of the slit light specified by the specifying means and a predetermined orthogonal base Further comprising means,
The measurement signal creating unit sets a plurality of the attention points each belonging to any of a plurality of groups along a short direction of the slit light, and a plurality of the plurality of attention points corresponding to each of the plurality of attention points. Create a measurement signal
The center position calculating means calculates a center position of the slit light in the measurement signal corresponding to any one of the attention points belonging to the group for each of the plurality of groups. Irradiation means for irradiating the measurement object with slit light from a predetermined irradiation direction;
Imaging means for imaging the measurement object irradiated with the slit light from the irradiation means from a predetermined imaging direction different from the irradiation direction, and outputting an imaging signal;
Measurement signal creating means for creating a measurement signal based on the imaging signal;
Correlation calculation means for performing a correlation calculation between the measurement signal and a predetermined luminance distribution model of the slit light;
Based on the result of the correlation calculation by the correlation calculation means, a specifying means for specifying an irradiation range of the slit light in the measurement signal;
A positional relationship setting unit capable of setting a relative positional relationship between the object to be measured, the irradiation unit, and the imaging unit to a plurality of different positional relationships ;
The imaging means images the object to be measured in a state where each of the plurality of positional relationships is set,
The measurement signal creation means extracts a signal representing luminance along the short direction of the slit light from the imaging signal for each of the plurality of imaging signals corresponding to each of the plurality of positional relationships, and extracts the signals from each of the signals representing the plurality of said luminance that is, the signal representing the luminance of a plurality of target points set along the short side direction, measuring device characterized that you extracted as a plurality of the measurement signal . Irradiation means for irradiating the measurement object with slit light from a predetermined irradiation direction;
Imaging means for imaging the measurement object irradiated with the slit light from the irradiation means from a predetermined imaging direction different from the irradiation direction, and outputting an imaging signal;
Measurement signal creating means for creating a measurement signal based on the imaging signal;
Correlation calculation means for performing a correlation calculation between the measurement signal and a predetermined luminance distribution model of the slit light;
Based on the result of the correlation calculation by the correlation calculation means, a specifying means for specifying an irradiation range of the slit light in the measurement signal;
A positional relationship setting unit capable of setting a relative positional relationship between the object to be measured, the irradiation unit, and the imaging unit to a plurality of different positional relationships ;
The imaging means images the object to be measured in a state where each of the plurality of positional relationships is set,
The measurement signal generation means generates a plurality of measurement signals based on a group of the imaging signals selected from the plurality of imaging signals corresponding to each of the plurality of positional relationships, group of repeating the imaging signal running to the measuring device according to claim Rukoto. In the measuring device according to claim 1 or 3 ,
Center position calculation for calculating the center position of the slit light in the measurement signal by calculating the projection of the measurement signal corresponding to the irradiation range of the slit light specified by the specifying means and a predetermined orthogonal base A measuring device comprising means. In the measuring device according to any one of claims 1 to 5 ,
A measurement apparatus comprising texture generation means for generating texture information on the surface of the object to be measured by integrating signals of the irradiation range of the slit light specified by the specification means for each of the plurality of imaging signals. Irradiation means for irradiating the measurement object with slit light from a predetermined irradiation direction;
Imaging means for imaging the measurement object irradiated with the slit light from the irradiation means from a predetermined imaging direction different from the irradiation direction, and outputting an imaging signal;
Measurement signal creating means for creating a measurement signal based on the imaging signal;
Correlation calculation means for performing a correlation calculation between the measurement signal and a predetermined luminance distribution model of the slit light;
Based on the result of the correlation calculation by the correlation calculation means, a specifying means for specifying an irradiation range of the slit light in the measurement signal;
Center position calculation for calculating the center position of the slit light in the measurement signal by calculating the projection of the measurement signal corresponding to the irradiation range of the slit light specified by the specifying means and a predetermined orthogonal base Means,
A measuring device comprising: