JP2012189479A - Shape measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for measuring a shape of an object to be measured at high speed and with high accuracy.SOLUTION: A device for measuring a shape of an object to be measured 21 comprises: a lattice-projection section 30 that includes a light source for lattice projection 31 having a light-source substrate 32 and a plurality of lattice-projection LEDs 33 disposed on the light-source substrate 32 and a lattice plate 34 that is disposed in parallel to the light-source substrate 32 and includes a lattice plane on which a one-dimensional lattice is drawn; an image-capturing section 11 for capturing an image of the object to be measured 21 on which the one-dimensional lattice is projected; and an analysis controller 12 for performing a phase analysis of the captured image to determine a shape of the object to be measured 21. Each optical axis of the plurality of lattice-projection LEDs 33 is inclined from a normal line of the light-source substrate 32 toward the object to be measured 21.

Description

  The present invention relates to a shape measuring apparatus that measures the shape of a measurement target object at high speed and with high accuracy.

  Conventionally, there is a method using a phase shift method as a method for non-contact and three-dimensionally measuring the shape of a measurement target object such as an object or a human body. In the phase shift method, a lattice image and an interference fringe image are sequentially photographed by a single photographing device while changing the phase, and the phase distribution of the lattice is calculated based on a plurality of lattice images and interference fringe images whose phases are changed. It is what you want.

  So far, various methods using the phase shift method have been proposed. For example, Patent Document 1 aims at performing highly accurate shape measurement that is not affected by lens aberration of a camera or projector in a shape measurement device using a camera. From a reference plate image on which a lattice is drawn, Rather than calculating the lens center coordinates of the camera or projector, the optical path through which the line of sight for each pixel of the camera passes and the optical path of the light projected from the projector are all obtained from a two-dimensional grid fixed to the reference plane. A shape measuring method and apparatus for calculating spatial coordinates as intersections of these optical paths are described.

Japanese Patent No. 2913021

However, in the method described in Patent Document 1, a grating substrate is provided on a moving mechanism to perform phase shift, and the grating substrate is mechanically moved. This moving mechanism is very expensive, for example, a piezo stage. Is.
In addition, it is difficult to perform phase shift of the grating at high speed, and there remains a problem in that the shape of an object moving at high speed cannot be measured, for example.

  Therefore, an object of the present invention is to provide a method for measuring the shape of an object to be measured at high speed and with high accuracy.

  The inventors diligently studied how to solve the above problems. As a result, as shown in FIG. 1, a light emitting device (light source) 1 in which a plurality of light emitting diodes (LEDs) 3 are arranged in a line on a surface 2a of a substrate 2 is prepared, and the LEDs 3 are sequentially turned on. As a result, it has been found that the phase of the grating projected onto the object to be measured can be shifted at high speed (hereinafter, the above method is referred to as “optical stepping method”).

  In FIG. 2, an example of a shape measuring apparatus provided with the said light source 1 is shown. The shape measuring apparatus 100 includes a light source substrate 2 and a lattice projection light source 1 including a plurality of lattice projection LEDs 3 arranged on the surface of the light source substrate 2, and a lattice plane on which a one-dimensional lattice is drawn. A grid projection unit 10 having a grid plate 4 arranged in parallel to the light source substrate 2, an imaging unit 11 for imaging a measurement target object 21 on which a one-dimensional grid is projected, and a captured image And an analysis control device 12 that obtains the shape of the measurement target object 21 by performing phase analysis processing. Using the shape measuring apparatus 100, a one-dimensional lattice drawn on the lattice plane of the lattice plate 4 is projected onto the measurement target object 21 by the lattice projection unit 10, and projected by sequentially lighting the LEDs 3 in the light source 1. The phase of the one-dimensional grating can be shifted at high speed.

  However, when an LED is used for the grid projection light source 1, the following problems occur. That is, as schematically shown in FIG. 3, when shape measurement is performed by the shape measurement apparatus 100, the measurement target object 21, the lattice projection unit 10, and the imaging unit 11 are each based on the principle of triangulation. Arranged to make vertices of triangles. At that time, the measurement target object 21 is arranged in front of the imaging unit 11 so that a desired shape measurement region on the surface of the measurement target object 21 can be imaged. Therefore, the grid projection unit 10 is viewed from the measurement target object 21. It is common to arrange in an oblique direction.

  Here, as shown in FIG. 4, the light emission intensity distribution of the grid projection LED 3 is distributed in a region near the optical axis of the grid projection LED 3, and a region where light effective for photographing the measurement target object 21 reaches. (Hereinafter referred to as “effective light arrival area”) depends on the performance of the imaging unit 11, but is a line that defines a limit position where effective light reaches from the grating projection LED 3 (hereinafter referred to as “effective light limit line”). It is a narrow region sandwiched between “). Therefore, when the measurement target object 21 is arranged in an oblique direction as viewed from the grid projection unit 10, the light emitted from the grid projection LED 3 does not reach the measurement target object 21 sufficiently, and as a result, the irradiated light The use efficiency of the is significantly reduced. As a result, the one-dimensional lattice projected onto the measurement target object 21, and thus the captured image, also becomes dark, and the measurement error increases.

  In order to avoid the above problem, when the entire grid projection unit 10 is directed toward the measurement target object 21, the coordinate axis of the grid projection unit 10 and the coordinate axis of the imaging unit 11 are different from each other. When processing is performed to obtain the shape of the measurement target object 21, it is necessary to perform coordinate conversion. As a result, the analysis process becomes complicated and a lot of time is required, and high-speed shape measurement is hindered.

Therefore, when the measurement target object 21 is placed in front of the grid projection unit 10 in a state where the positional relationship between the grid projection unit 10 and the imaging unit 11 (the state where both coordinate systems are the same) is fixed, it is viewed from the imaging unit 11. Since the measurement target object 21 exists obliquely forward, it is necessary to perform image data conversion processing such as rotation processing on the obtained image data and perform high-speed shape measurement. Can not be.
In addition, since the imaging unit 11 captures the measurement target object 21 from an oblique direction, there is a possibility that the region on the measurement target object 21 whose shape is to be measured cannot be appropriately captured.

  As described above, when measuring the shape of the measurement target object 21, the positional relationship among the grid projection unit 10, the imaging unit 11, and the measurement target object 21 is limited, and the light emitted from the grid projection light source 1 is used. There is a demand for a method of effectively irradiating the measurement target object 21 and improving the usage efficiency of the irradiated light.

  Thus, as a result of intensive investigations on how to improve the use efficiency of the irradiation light from the LEDs 3 under the above restrictions, the inventors have arranged a plurality of grid projection LEDs 3 on the light source substrate 2, and each of the LEDs 3. It has been found that it is effective to arrange the optical axis so as to be inclined toward the measurement target object 21 with respect to the normal line of the light source substrate 2, and the present invention has been completed.

  By the way, when acquiring the three-dimensional image data of the measurement target object 21, it is necessary to acquire the luminance and hue data of the measurement target object 21 together with the three-dimensional coordinates of the surface of the measurement target object 21. Therefore, it is necessary to provide an imaging light source for irradiating the measurement target object 21 with light of a predetermined color. However, if an imaging light source is provided in addition to the grid projection light source 11, it is difficult to reduce the size of the apparatus. There's a problem. Thus, as a result of intensive studies, the inventors have found that it is effective to configure the grid projection unit 10 to further include an imaging LED, and have completed the present invention.

  That is, the shape measuring device of the present invention is a device for measuring the shape of an object to be measured, and includes a light source for lattice projection comprising a light source substrate and a plurality of light emitting diodes for lattice projection arranged on the light source substrate. A grid projection unit including a grid surface on which the one-dimensional grid is drawn and a grid plate arranged in parallel to the light source substrate; and imaging for imaging the measurement target object on which the one-dimensional grid is projected And an analysis device that performs a phase analysis process on the photographed image to obtain the shape of the measurement target object, and each of the optical axes of the plurality of grating projection light emitting diodes includes the light source substrate. It is characterized in that it is inclined toward the measurement object side with respect to the normal line.

  Moreover, in the shape measuring apparatus of the present invention, the surface of the light source substrate has a recess or a protrusion, and each of the plurality of grating projection light emitting diodes is disposed in the recess or the protrusion. It is a feature.

  In the shape measuring apparatus of the present invention, the grid projection light source further includes a plurality of imaging light emitting diodes for illuminating the measurement target object.

  In the shape measuring apparatus of the present invention, each optical axis of the imaging light emitting diode passes through the lattice plate.

  In the shape measuring apparatus of the present invention, a light diffusing plate is further provided between the plurality of imaging light emitting diodes and the grating plate.

  In the shape measuring apparatus of the present invention, it is preferable that an interval between the plurality of imaging light emitting diodes is smaller than an interval between the grating projection light emitting diodes.

  The light emitting device of the present invention includes a substrate and a plurality of light emitting diodes disposed on the substrate, and an optical axis of each of the plurality of light emitting diodes is inclined with respect to a normal line of the substrate. It is characterized by this.

  In the light emitting device of the present invention, the surface of the substrate has a concave portion or a convex portion, and each of the plurality of light emitting diodes is disposed in the concave portion or the convex portion. .

  According to the present invention, since the phase shift can be performed at high speed by sequentially turning on four or more light sources, the shape of the measurement target object can be measured at high speed and with high accuracy.

It is a figure which shows the light source which arranged several LED on the surface of the board | substrate for light sources. It is a figure which shows the shape measuring apparatus using several LED. It is a figure which shows the arrangement | positioning relationship of a grating | lattice projection part, an imaging part, and a measurement object. It is a figure which shows the effective irradiation area | region among the lights irradiated from LED. It is a figure which shows the shape measuring apparatus by this invention. It is a figure which shows an example of arrangement | positioning of LED in the light-emitting device by this invention. It is a figure which shows another example of arrangement | positioning of LED in the light-emitting device by this invention. It is a figure which shows the shape measuring apparatus further provided with LED for imaging by this invention. It is a figure which shows the shape measuring apparatus further provided with LED for imaging irradiated via the lattice plate by this invention. It is a figure which shows a shape measuring apparatus provided with LED for imaging by this invention. It is a figure which shows the shape measuring apparatus provided with imaging LED irradiated via a lattice plate by this invention. It is a figure which shows the shape measurement principle of the measurement object by the optical stepping method. It is a figure which shows the shape measurement principle of the measurement target object by the optical stepping method using a reference plane. It is a figure which shows the relationship between the phase shift amount and brightness | luminance in an optical stepping method.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 5 is a diagram illustrating a shape measuring apparatus for a measurement target object according to the present invention. The shape measuring apparatus 200 includes a lattice projection light source 31 including a light source substrate 32 and a plurality of lattice projection LEDs 33 arranged on the light source substrate 32, and a lattice plane on which a one-dimensional lattice is drawn. A grating projection unit 30 having a grating plate 34 arranged in parallel to the light source substrate 32, an imaging unit 11 that images the measurement target object 21 on which a one-dimensional grating is projected, and a phase with respect to the captured image And an analysis device 12 that performs an analysis process and obtains the shape of the measurement target object 21. Here, it is important that the optical axes of the plurality of grid projection LEDs 33 are inclined toward the measurement target object 21 with respect to the normal line of the light source substrate 32. Hereinafter, each configuration of the shape measuring apparatus 200 will be described.

The lattice projection unit 30 projects a one-dimensional lattice onto the measurement target object 21 when measuring the shape of the measurement target object 21. By using a plurality of LEDs for the grid projection light source 31 and sequentially turning on the LEDs, the phase of the one-dimensional grid projected on the measurement target object 21 can be shifted at high speed. 21 shape measurement can be performed at high speed.
As described above, when the optical axis of the grid projection LED 33 is arranged parallel to the normal line of the light source substrate 32, the light emitted from the grid projection light source 31 is effectively applied to the measurement target object 21. Not reach. Therefore, in the present invention, each optical axis of the plurality of grid projection LEDs 33 is configured to be inclined toward the measurement target object 21 side. Thereby, the use efficiency of the light irradiated from the grid projection LED 33 can be remarkably improved, and as a result, the accuracy of the shape measurement can also be improved.

  The method of arranging the plurality of grid projection LEDs 33 on the light source substrate 32 so that the optical axis of the LEDs 33 is inclined with respect to the normal line of the light source substrate 32 is not limited. For example, by providing a concave portion or a convex portion on the surface of the light source substrate 32 and disposing each LED 33 in the concave portion or the convex portion, each LED 33 can be disposed in an inclined manner. Specifically, as shown in FIG. 6, by providing a v-shaped recess 32 b on the surface of the light source substrate 32, each LED 33 can be disposed in an inclined manner. Further, as shown in FIG. 7, the lattice projection LED 33 can be arranged by providing a v-shaped convex portion 32 c on the surface of the light source substrate 32.

  The angle of inclination of the optical axis of the LED 33 with respect to the normal direction of the light source substrate 32 is different depending on the effective light arrival area of the LED 33 and also depending on the positional relationship with the measurement target object 21, and thus a specific angle range is defined. However, it is set so that the measurement target object 21 is arranged in an area where at least all the effective light arrival areas of the LEDs 33 are overlapped.

  6 and 7, all of the optical axes of the grid projection LEDs 33 are inclined at the same angle with respect to the normal of the surface 32a of the light source substrate 32. However, the optical axes of the LEDs 33 are These may be arranged at different angles. For example, the inclination angle can be increased for the LEDs far from the measurement target object 21, and the inclination angle can be decreased for the LEDs close to the measurement target object 21.

  The number of grid projection LEDs 33 is not limited at all in terms of improving the use efficiency of the light irradiated to the measurement target object 21, but depends on the phase analysis method used in the shape measurement. For example, when the optical stepping method described later is used as the phase analysis method, four or more, and in the case of the phase analysis method based on the total space table method, three or more are sufficient.

  The shape of the grid projection LED 33 can be not only a point light source but also a linear light source. In general, since the output of the LED is small, a plurality of point light sources can be arranged to form a linear light source to increase the output.

  The interval between the plurality of grid projection LEDs 33 is not limited in terms of improving the use efficiency of the light irradiated to the measurement target object 21, but may be limited by the phase analysis method used in the shape measurement. is there. For example, when the optical stepping method described later is used as the phase analysis method, it is necessary to arrange them at equal intervals in the X-axis direction. On the other hand, in the case of the phase analysis method based on the total space table formation method, it is not always necessary to arrange them at equal intervals.

  The one-dimensional lattice drawn on the lattice plane 34a of the lattice plate 34 is composed of straight lines arranged at equal intervals and parallel to the Y-axis direction. The light irradiated from the grid projection LED 33 passes through the grid plate 34, so that a one-dimensional grid drawn on the grid surface 34 a is projected onto the measurement target object 21.

  The imaging unit 11 images the measurement target object 21 and the measurement target object 21 on which the one-dimensional lattice is projected by the lattice projection unit 10. As the imaging unit 11, for example, a CMOS camera or a CCD camera can be used.

  The analysis control device 12 obtains the shape of the measurement target object 21 by performing a phase analysis process on the image of the measurement target object 21 photographed by the imaging unit 11, and switches the lighting of the LED 3 in the lattice projection unit 10. Control of the imaging and imaging of the imaging unit 11 is performed. As the analysis control device 12, for example, a personal computer (PC) can be used.

With such a shape measuring apparatus according to the present invention, the shape of the object to be measured can be measured at high speed.
In addition, since the optical axis of the grid projection LED is arranged to be inclined toward the measurement target object with respect to the normal of the light source substrate, the light irradiated from the grid projection LED is effectively irradiated to the measurement target object. In addition, the use efficiency of irradiation light, and hence the accuracy of shape measurement can be improved.

  By providing an imaging LED in the shape measuring apparatus 200 of the present invention described above, a measurement target that is necessary for acquiring the three-dimensional image data of the measurement target object 21 together with the shape measurement of the measurement target object 21 It becomes possible to acquire brightness and hue data of the object 21.

  FIG. 8 shows a shape measuring apparatus 300 including a plurality of imaging LEDs 45 in the lattice projection light source 41 of the lattice projection unit 40. The imaging LED 45 has a predetermined wavelength (to the measurement target object 21 in order to acquire luminance and hue data of the measurement target object 21 that is necessary for acquiring three-dimensional image data of the measurement target object 21. Color).

  Here, the imaging LED 45 is arranged on the measurement target object 21 side on the light source substrate 42 together with the grid projection LED 43. As a result, the grid projection light source 41 becomes compact, the imaging LED 45 and the grid projection LED 43 can be easily controlled, and it is necessary for acquiring three-dimensional image data together with the shape measurement of the measurement target object 21. Thus, the brightness and hue data of the measurement target object 21 can be acquired instantaneously.

  Further, the grating plate 44 for projecting the one-dimensional grating onto the measurement target object 21 is configured not to enter the effective light arrival area of the imaging LED 45.

  When the shape of the measurement target object 21 is measured, the grid projection LEDs 43 are sequentially turned on with all the imaging LEDs 45 turned off. On the other hand, when the measurement target object 21 is imaged, all the imaging LEDs 45 are turned on at the same time with the grid projection LED 43 being turned off.

  The imaging LED 45 can be not only a point light source but also a linear light source, similar to the grid projection LED 43. Further, since the output of the imaging LED 45 is small, it is possible to arrange a plurality of point light sources to form a linear light source to increase the output. Further, the wavelength of the light emitted by the imaging LED 45 is appropriately selected according to the application.

The number of the imaging LEDs 45 is not limited at all in terms of improving the use efficiency of the light irradiated to the measurement target object 21, and it is sufficient that the measurement target object 21 can be clearly photographed.
Further, the interval between the plurality of imaging LEDs 45 is not particularly limited, and may be set appropriately as necessary.

  Note that the optical axis of the imaging LED 45 is not necessarily inclined with respect to the normal line of the light source substrate 42, unlike the case of the grid projection LED 43, but it is inclined to the measurement target object 21 side. Thus, the measurement target object 21 can be illuminated more brightly and a clearer image can be taken.

  FIG. 9 shows a shape measuring apparatus having an imaging LED 45 having a configuration different from that of FIG. The difference between the shape measuring apparatus 400 and the shape measuring apparatus 300 shown in FIG. 8 is that the lattice plate 44 in the shape measuring apparatus 400 is included in the effective light arrival area of the imaging LED 45. Therefore, the light emitted from the imaging LED 45 passes through the grating plate 44, and thus a one-dimensional grating is projected onto the measurement target object 21. However, as will be apparent from the principle of shape measurement described later, the lattice patterns projected from the LEDs 45 are superimposed by arranging the imaging LEDs 45 with a narrow interval and lighting all the imaging LEDs 45 simultaneously. As a result, the one-dimensional lattice projected on the measurement target object 21 can be erased. In this way, the measurement target object 21 is illuminated with light of a predetermined color from which the one-dimensional lattice is erased. Therefore, the measurement target object 21 that is necessary for acquiring three-dimensional image data of the measurement target object 21 is used. Luminance and hue data can be acquired.

  Further, in the shape measuring apparatus 400, a light diffusing plate such as ground glass is further arranged between the plurality of imaging LEDs 45 and the lattice plate 44, so that the imaging LED 45 is turned on on the measurement target object 21. The measurement object 21 can be imaged without making the projected one-dimensional lattice more noticeable. The light diffusing plate is disposed at an appropriate position so as not to adversely affect the projection of the one-dimensional grating onto the measurement target object 21 via the grating plate 44.

  In the shape measuring apparatus 400 described above, the interval between the plurality of imaging LEDs 45 is preferably as small as possible. The interval between the plurality of imaging LEDs 45 can be adjusted not only by narrowing the interval between the LEDs 45 but also by inclining the direction in which the plurality of imaging LEDs 45 are arranged with respect to the X axis in the LED plane.

  In FIG. 9, the imaging LED 45 is drawn smaller than the grid projection LED 43, which means that the interval between the imaging LEDs 45 is set finely. Note that the dimensions are not meant to be smaller than.

  Thus, by providing the imaging LED 45, the measurement target object necessary for irradiating the measurement target object 21 with light of a predetermined wavelength (color) and acquiring three-dimensional image data of the measurement target object 21 21 luminance and hue data can be acquired instantaneously.

  FIG. 10 is a diagram illustrating a shape measuring apparatus for a measurement target object according to the present invention. The shape measuring apparatus 500 includes a grating projection light source 51 including a light source substrate 52 and a plurality of grating projection LEDs 53 arranged on the light source substrate 52, and a grating surface on which a one-dimensional grating is drawn. A grating projection unit 50 having a grating plate 54 arranged in parallel to the light source substrate 52, and a plurality of imaging LEDs 55 arranged on the light source substrate 52, and a measurement target object on which a one-dimensional grating is projected The imaging unit 11 that captures the image 21 and the analysis control device 12 that performs a phase analysis process on the captured image to obtain the shape of the measurement target object 21 are provided. Here, the grating plate 54 is configured so that the optical axis of the imaging LED 55 does not pass through the grating plate 54. Hereinafter, each configuration of the shape measuring apparatus 500 will be described.

  The lattice projection unit 50 projects a one-dimensional lattice onto the measurement target object 21 when measuring the shape of the measurement target object 21. Here, the grid projection LEDs 53 are arranged so that their optical axes are parallel to the normal direction of the light source substrate 52. By using a plurality of LEDs for the grid projection light source 51 and sequentially turning on the LEDs, it is possible to shift the phase of the one-dimensional grid projected on the measurement target object 21 at a high speed. Can be measured at high speed.

  The number of grid projection LEDs 53 is not limited at all in terms of improving the use efficiency of the light irradiated to the measurement target object 21, but depends on the phase analysis method used in the shape measurement. For example, when the optical stepping method described later is used as the phase analysis method, four or more, and in the case of the phase analysis method based on the total space table method, three or more are sufficient.

  Further, the shape of the grid projection LED 53 can be not only a point light source but also a linear light source. Further, since the output of the LED is small, it is possible to arrange a plurality of point light sources to form a linear light source and increase the output.

  The interval between the plurality of grid projection LEDs 53 is not limited in terms of improving the use efficiency of light irradiated to the measurement target object 21, but may be limited by the phase analysis method used in the shape measurement. is there. For example, when the optical stepping method described later is used as the phase analysis method, it is necessary to arrange them at equal intervals in the Y-axis direction. On the other hand, in the case of the phase analysis method based on the total space table formation method, it is not always necessary to arrange them at equal intervals.

  The imaging LED 55 has a predetermined wavelength (color) for the measurement target object 21 in order to acquire brightness and hue data of the measurement target object 21 that is necessary for acquiring three-dimensional image data of the measurement target object 21. ).

  Here, the imaging LED 55 is disposed on the measurement target object 21 side on the light source substrate 52 together with the grid projection LED 53. As a result, the grid projection light source 51 becomes compact, and the imaging LED 55 and the grid projection LED 53 can be easily controlled, and is necessary for acquiring three-dimensional image data together with the shape measurement of the measurement target object 21. Thus, the brightness and hue data of the measurement target object 21 can be acquired instantaneously.

  When measuring the shape of the measurement target object 21, the grid projection LEDs 53 are sequentially turned on with all the imaging LEDs 55 turned off. On the other hand, when the measurement target object 21 is imaged, all of the imaging LEDs 55 are turned on simultaneously with the grid projection LEDs 53 turned off.

  The one-dimensional lattice drawn on the lattice surface 54a of the lattice plate 54 is composed of straight lines arranged at equal intervals and parallel to the Y-axis direction. The light irradiated from the grid projection LED 53 passes through the grid plate 54, and thus a one-dimensional grid drawn on the grid surface 54 a is projected onto the measurement target object 21.

  The imaging unit 11 images the measurement target object 21 and the measurement target object 21 on which the one-dimensional lattice is projected by the lattice projection unit 10. As the imaging unit 11, for example, a CMOS camera or a CCD camera can be used.

  The analysis control device 12 obtains the shape of the measurement target object 21 by performing a phase analysis process on the image of the measurement target object 21 photographed by the imaging unit 11, and the lattice projection LED 53 in the lattice projection unit 50. Lighting switching control and imaging control of the imaging unit 11 are performed. As the analysis control device 12, for example, a personal computer (PC) can be used.

  FIG. 11 shows a shape measuring apparatus having an imaging LED 55 having a configuration different from that of FIG. The difference between the shape measuring apparatus 600 and the shape measuring apparatus 500 shown in FIG. 10 is that the lattice plate 54 in the shape measuring apparatus 500 is included in the effective light arrival area of the imaging LED 55. Therefore, the light emitted from the imaging LED 55 passes through the grating plate 54, and thus a one-dimensional grating is projected onto the measurement target object 21.

  However, since the lattice patterns projected from the LEDs 55 are superimposed by arranging the imaging LEDs 55 with a narrow interval and lighting all the imaging LEDs 55 at the same time, they are projected onto the measurement target object 21 as a result. One-dimensional lattice can be erased. In this way, the measurement target object 21 is illuminated with light of a predetermined color from which the one-dimensional lattice is erased. Therefore, the measurement target object 21 that is necessary for acquiring three-dimensional image data of the measurement target object 21 is used. Luminance and hue data can be acquired.

  Further, in the shape measuring apparatus 600, a light diffusing plate such as frosted glass is further arranged between the plurality of imaging LEDs 55 and the lattice plate 54, so that the imaging LED 55 is turned on on the measurement target object 21. The measurement object 21 can be imaged without making the projected one-dimensional lattice more noticeable. The light diffusing plate is arranged at an appropriate position so as not to adversely affect the projection of the one-dimensional grating onto the measurement target object 21 via the grating plate 54.

  In the shape measuring apparatus 600 described above, the interval between the plurality of imaging LEDs 55 is preferably as small as possible. The interval between the plurality of imaging LEDs 55 can be adjusted not only by narrowing the interval between the LEDs 55 but also by inclining the direction in which the plurality of imaging LEDs 55 are arranged with respect to the X axis in the LED plane.

  In FIG. 11, the imaging LED 55 is drawn smaller than the grid projection LED 53. This means that the interval between the imaging LEDs 55 is set finely, and the grid projection LED 55 Note that the dimensions are not meant to be smaller than.

  In this way, by providing the imaging LED 55, the measurement target object 21 is irradiated with light of a predetermined wavelength (color) together with the shape measurement of the measurement target object 21, and three-dimensional image data of the measurement target object 21 is acquired. Therefore, it is possible to instantaneously acquire luminance and hue data of the measurement target object 21 that is necessary.

  Using the shape measuring device of the present invention described above, the imaging target 12 images the measurement target object 21 on which the one-dimensional lattice pattern is projected, and performs a phase analysis process on the captured image to measure the measurement target object. However, the method of phase analysis processing is not limited, and various methods can be employed. Here, as an example of the phase analysis method, an optical stepping method and an entire space table forming method will be described. Therefore, although the case where shape measurement is performed using the shape measurement apparatus 200 having the five grid projection LEDs 33 will be described, measurement can be similarly performed when the number of LEDs 33 is other than five.

[Shape measurement principle]
(When the reference plane is not used)
FIG. 12 is a diagram showing the principle of measuring the shape of the measurement target object 21 by the optical stepping method using the shape measuring apparatus 200 according to the present invention. The shape measuring apparatus 200 includes L ₋₂ , L ₋₁ , L ₀ , L _1, and L _{1 that} are the light source substrate 32 and five grid projection LEDs 33 arranged in a line at equal intervals on the light source substrate 32. A grid projection unit 30 having a grid projection light source 31 composed of ₂ and a grid plate 34 having a grid surface 34 a on which a one-dimensional grid is drawn, and the photographing unit 11 are provided. In FIG. 12, the analysis control device 12 is omitted.
Here, the center position (that is, the position of L ₀ ) between the LEDs at both ends in the five grid projection LEDs 33 L ₋₂ , L ₋₁ , L ₀ , L ₁ and L ₂ is the origin O, and the five The X axis is taken in the direction passing through the LED, and the Y axis and Z axis perpendicular to each other are taken in the direction perpendicular to the X axis (hereinafter, the position in the Z axis direction from the LED surface is referred to as “height”). The measurement target object 21 is arranged in the Z-axis direction.
Note that the position of the origin O is defined in the same manner as described above even when the number of LEDs is other than 5, that is, the center position between the light sources at both ends in four or more light sources.

The spacing between the LEDs is l. Hereinafter, a surface including five LEDs L ₋₂ , L ₋₁ , L ₀ , L ₁ and L _{2 and} having Z = 0 is referred to as an “LED surface”.

  The one-dimensional lattice drawn on the lattice plane 34a of the lattice plate 34 is composed of straight lines arranged at equal intervals and parallel to the Y-axis direction. The light emitted from the light source 31 for projecting the lattice passes through the lattice plate 34 so that the one-dimensional lattice drawn on the lattice surface 34 a is projected onto the measurement target object 21. The interval between the straight lines constituting the one-dimensional lattice is p, and the interval between the LED surface and the lattice surface 34a is d. Further, among the center positions between the straight lines constituting the one-dimensional lattice, the one having the shortest distance from the Z axis is defined as an origin E, and the intersection between the lattice plane 34a and the Z axis is defined as C.

In the following description, the brightness distributions of five LEDs L ₋₂ , L ₋₁ , L ₀ , L _1, and L ₂ are uniform in the observation range with Z = constant X and Y axis directions. Are equal. If it is not uniform, the distribution may be considered as a coefficient, but here it is assumed to be uniform in order to simplify handling.

Now, only sequentially lighting the L _n is LED, and considering that one-dimensional lattice is projected onto the measuring symmetric object 21. At this time, the transmittance distribution of the one-dimensional grating at Z = d has a cosine wave shape, and the luminance distribution of the shadow of the one-dimensional grating irradiated by the LED L _n is expressed by the following equation.

ここで、Φは位相、ａ_gは振幅、ｂ_gは背景輝度、ｘ_gは格子面３４ａでのｘ座標、ｅは格子面３４ａの原点Ｅ（Φ＝０）と点Ｃとの間の距離である。
まず、５つのＬＥＤのうち、中央のＬ₀の点灯により１次元格子が投影された計測対象物体２１上の位置Ｓ（ｘ，ｙ，ｚ）における輝度Ｉ₀は、近似的に次式で表される。

Here, Φ is the phase, a _g is the amplitude, b _g is the background luminance, x _g is the x coordinate on the lattice plane 34a, and e is the distance between the origin E (Φ = 0) of the lattice plane 34a and the point C. It is.
First, Table of the five LED, the brightness I ₀ at the position S on the measurement object 21 to the one-dimensional grating is projected (x, y, z) by turning on the middle L ₀ is an approximation by the following equation Is done.

ここで、任意の点の輝度は、光源からの距離の自乗に反比例することを考慮している。また、図１２に示すように、計測対象物体２１上の１点Ｓには、図１２における格子面３４ａ上の１次元格子のＧ点の影が投影されている。

Here, it is considered that the luminance at an arbitrary point is inversely proportional to the square of the distance from the light source. As shown in FIG. 12, the shadow of the point G of the one-dimensional lattice on the lattice plane 34a in FIG.

  At this time, from the geometric relationship,

の関係がある。

There is a relationship.

Next, when the LED is switched from L ₀ to L ₁ , the shadow of the point G is projected onto the point A in the (x, y) plane where Z = z. At this time, a shadow of point F of the one-dimensional lattice is projected onto point S.
The luminance I _{1 at the} position S (x, y, z) by the LED L ₁ is obtained as follows.
That is, by switching the LED from L ₀ to L ₁ , the phase (unwrapped phase) of the one-dimensional grating projected onto the measurement target object 21 is shifted by an amount given by the following equation (4). .

この位相シフト量Ψは、以下のようにして求められる。すなわち、図１２におけるΔＬ₀Ｌ₁Ｇと△ＳＡＧとが相似であるため、

This phase shift amount Ψ is obtained as follows. That is, since ΔL ₀ L ₁ G and ΔSAG in FIG. 12 are similar,

となる。また、△ＳＡＬ₁と△ＦＧＬ₁とが相似であるため、

It becomes. Also, because △ SAL ₁ and △ FGL ₁ are similar,

となる。式（５）および（６）から、

It becomes. From equations (5) and (6)

となる。また、式（４）および（７）から、

It becomes. From equations (4) and (7)

となる。こうして、ＬＥＤをＬ₀からＬ₁に切り替えたときに、計測対象物体２１に投影された１次元格子の位相シフト量Ψの値が求められた。この位相シフト量Ψは、ｚに依存することが分かる。

It becomes. Thus, when the LED was switched from L ₀ to L ₁ , the value of the phase shift amount Ψ of the one-dimensional grating projected onto the measurement target object 21 was obtained. It can be seen that this phase shift amount Ψ depends on z.

Similarly, by switching from L ₀ is a LED to L _n is a LED, for shifting the phase only nΨ compared to equation (2), the luminance I _n at position S (x, y, z), the following It becomes an expression.

この式（９）において、

In this equation (9),

と置き直すと、

And put it again

となる。
こうして、Ｌ_nを点灯したときの、位置Ｓ（ｘ，ｙ，ｚ）における輝度Ｉ_nを求めることができた。
なお、計測対象物体２１の反射率ｒを考慮する場合は、ａおよびｂに反射率ｒを掛ければよいが、ここでは説明を簡単化するために省略する。

It becomes.
Thus, when the lit L _n, were able to determine the intensity I _n at position S (x, y, z) .
Note that when the reflectance r of the measurement target object 21 is taken into consideration, a and b may be multiplied by the reflectance r, but are omitted here for the sake of simplicity.

(Relationship between phase shift amount Ψ and height z)
Next, in order to obtain the height z, the relationship between the height z and the phase shift amount Ψ or the phase Φ is obtained. When the phase shift amount Ψ is obtained, from the equation (8),

が得られ、高さｚを求めることができる。この場合、等位相線は等高線となっている。

And the height z can be obtained. In this case, the isophase lines are contour lines.

(Relationship between phase Φ and height z)
Also, from equation (12)

となり、位相Φが求められると、高さｚが求められる。この場合、等位相線はｘの関数となっており、等高線とはならない。

When the phase Φ is obtained, the height z is obtained. In this case, the isophase line is a function of x and does not become a contour line.

  As described above, if the phase shift amount ψ or the phase Φ can be obtained, the height z can be obtained from the equation (14) or the equation (15) regardless of the position of the imaging unit 11. A method for obtaining the phase shift amount ψ and the phase Φ will be described later.

  For the x and y coordinates, the phase in the X-axis direction and the Y-axis direction are obtained by various methods, for example, the Fourier transform grid method, and further, phase connection is performed to obtain the x-coordinate and y-coordinate at each point. Each can be obtained (for example, refer to Japanese Patent No. 3281918).

  In FIG. 12, in the state where the arrangement of the configuration other than the five LEDs (including the X, Y, and Z axes) is all fixed, the five LEDs are arranged on the X axis around the origin O in the plane of Z = 0. It can be tilted with respect to. That is, the five LEDs do not need to be parallel to the X axis. In this case, the interval l between the five LEDs in the above description is the interval between the LEDs in the X-axis direction (that is, the direction perpendicular to the straight line constituting the one-dimensional lattice) (that is, the interval between the five LEDs). X-axis direction component) is used. Although it is difficult to physically reduce the interval between the LEDs, the interval between the LEDs in the X-axis direction can be easily reduced by tilting the five LEDs with respect to the X-axis as described above. Become.

Further, in FIG. 12, in the state where all the arrangements other than the five LEDs (including the X, Y, and Z axes) are fixed, five LEDs L- ₂ , L- Each of L ₁ , L ₀ , L ₁ , and L ₂ can be arranged at an arbitrary position in the Y-axis direction. That is _L-2 in five _{LED, L- 1, L 0,} L 1, L 2 need only equally spaced in the X-axis direction.

  Thus, the coordinates x, y, and z of the point S on the measurement target object 21 can be obtained, and the shape of the measurement target object 21 can be obtained.

(When using a reference surface)
Next, the principle of shape measurement when using a reference surface will be described. The shape measuring method includes a grating projection light source including four or more light sources, a grating plate including a grating surface having a one-dimensional grating, and arranged in parallel to the grating projection light source, and an imaging unit, A shape measuring device having a photographing unit disposed on a light source surface in which the center of the lens of the photographing unit includes a light source for lattice projection and is parallel to the lattice plate, and a reference plate including a reference surface disposed in parallel to the lattice surface In this method, the shape of the measurement target object is measured using four or more light sources that are sequentially turned on and the reference plane is imaged by the imaging unit while shifting the phase of the one-dimensional grating projected onto the reference surface. And a step of arranging the measurement target object between the grating plate and the reference plate, sequentially turning on four or more light sources and shifting the phase of the one-dimensional grating projected onto the measurement target object, Shooting objects to be measured A step that, by performing a phase analysis processing on the image of the image and the measurement object of the photographed reference plane, and determining the shape of the measurement object. Here, the four or more light sources are arranged at equal intervals in a direction perpendicular to the straight line constituting the one-dimensional grating, and the distance from the light source surface is the phase of the projected one-dimensional grating at a predetermined position. And the phase at the intersection of the straight line passing through the lens center and a predetermined position and the reference plane.
Hereinafter, the principle of another shape measuring method according to the present invention will be described by taking as an example the case where the number of light sources constituting the grid projection light source is five, but this case is not limited to the case of five light sources. To do.

FIG. 13 shows the shape measurement apparatus 1 shown in FIG. 12, further comprising a reference plate 13 having a reference surface 13a parallel to the lattice plane 34a (that is, the LED surface) at a distance z _R from the LED surface. Device 200. Here, the center V of the lens of the photographing unit 11 is arranged at a position of X = v. That is, the distance in the X-axis direction from the origin O to the center V of the lens is v. The measurement target object 21 is disposed between the lattice plate 34 and the reference flat plate 13.
Using this shape measuring apparatus 200, first, a one-dimensional grating is projected onto the reference plane 13a, and the phase Φ _R distribution is recorded. Then, the measurement target object 21 is placed in front of the reference plane 13a, and the measurement is performed. The phase Φ _S of the projected one-dimensional grating at the point S on the target object 21 is obtained. Thereby, in each pixel of the imaging unit 11, z or a height h _s = z _R from the reference surface 13 a is calculated from the phase difference (Φ _S −Φ _R ) between the reference surface 13 a and the point S on the measurement target object 21. -Z can be determined. The principle will be described below.

If one pixel U of the photographing unit 11 is not arranged between the grid plate 34 and the reference flat plate 13, the measurement target object 21 arranges the point R on the reference plane 13a when the measurement target object 21 is not arranged between the lattice plate 34 and the reference flat plate 13. If it is, the point S on the measurement target object 21 is viewed. The phase at the point S of the one-dimensional grating projected on the measurement target object 21 is Φ _S , and the phase at the point R is Φ _R. Let Q be the intersection of a straight lattice plane 34a connecting the point R and the origin O. At this time, the phases Φ _S and Φ _R are the same as the phases of the one-dimensional grating at the points G and Q, respectively, and the relationship of the following equation is obtained from the phase difference between them.

また、△ＳＰＯと△ＧＱＯとが相似であるため、

Also, because △ SPO and △ GQO are similar,

となる。式（１６）および（１７）から、

It becomes. From equations (16) and (17)

となる。また、△ＳＰＲと△ＶＯＲとが相似であるため、

It becomes. Also, since ΔSPR and ΔVOR are similar,

となる。式（１８）および（１９）から、

It becomes. From equations (18) and (19)

となる。この式（２０）から、高さｚは、

It becomes. From this equation (20), the height z is

となる。
こうして、式（２１）から、カメラの画素の基準面１３ａにおける位相Φ_Rおよび計測対象物体２１上の点Ｓの位相Φ_Sから、点Ｓのｚ座標を求めることができる。また、等位相差（Φ_S−Φ_R）線は等高線となる。

It becomes.
Thus, from the equation (21), the z coordinate of the point S can be obtained from the phase Φ _{R on} the reference plane 13 a of the camera pixel and the phase Φ _S of the point S on the measurement target object 21. Further, the isophase difference (Φ _S −Φ _R ) line is a contour line.

For the x and y coordinates, as in the case where the reference plane 13a (that is, the reference flat plate 13) is not used, the phases in the X-axis direction and the Y-axis direction are obtained by, for example, the Fourier transform grid method, and the phase connection is performed. By performing the above, x-coordinate and y-coordinate at each point can be obtained.
As in the case of FIG. 12, in FIG. 13, in the state where all the arrangements other than the five LEDs (including the X, Y, and Z axes) are fixed, the five LEDs are arranged in the plane of Z = 0. It can be arranged to be inclined with respect to the X axis around the origin O. That is, the five LEDs do not need to be parallel to the X axis. In this case, the interval l between the five LEDs in the above description is the interval between the LEDs in the X-axis direction (that is, the direction perpendicular to the straight line constituting the one-dimensional lattice) (that is, the interval between the five LEDs). X-axis direction component) is used. Although it is difficult to physically reduce the interval between the LEDs, the interval between the LEDs in the X-axis direction can be easily reduced by tilting the five LEDs with respect to the X-axis as described above. Become.

Further, in FIG. 13, in a state where all the configurations other than the five LEDs (including the X, Y, and Z axes) are fixed, the five LEDs L- ₂ , L- Each of L ₁ , L ₀ , L ₁ , and L ₂ can be arranged at an arbitrary position in the Y-axis direction. That is _L-2 in five _{LED, L- 1, L 0,} L 1, L 2 need only equally spaced in the X-axis direction.

  Thus, the coordinates x, y, and z of the point S on the measurement target object 21 can be obtained, and the shape of the measurement target object 21 can be obtained.

  Thus, the coordinates x, y, and z of the point S on the measurement target object 21 can be obtained, and the shape of the measurement target object 21 can be obtained.

(Phase analysis by optical stepping method)
Next, a method for obtaining the phase Φ and the phase shift amount ψ necessary for obtaining the height z will be described.
As described above, the conventional phase shift method directly moves the grating of FIG. 12 or 13 to divide the phase 2π by the integer N and shift the phase by 2π / N at all positions. In the phase shift method of the present invention, by sequentially turning on and off the five LEDs, the phase of the one-dimensional grating projected onto the measurement target object 21 is expressed by the phase shift amount ψ represented by the equation (14). A phase shift is performed by shifting five times at equal intervals (including the initial position). This phase shift amount Ψ is not normally obtained by dividing 2π into five equal parts. Further, as is clear from the equation (14), the phase shift amount Ψ varies depending on the value of z.

FIG. 14 shows the relationship between the luminance of the sample point and the phase shift amount when the phase of the one-dimensional grating whose luminance changes in a cosine wave shape is phase-shifted at equal intervals by the phase shift amount ψ. In the optical stepping method, the phase Φ at I ₀ is the phase to be obtained, and the phase is shifted by Ψ each time L _n is switched and sequentially turned on. At this time, the luminance is expressed by the above equation (13).

となる。ここで、未知数はΦ、Ψ、ａおよびｂの４つであり、これらの式から位相Φのラッピングされた値φおよびΨのラッピングされた値ψは、それぞれ以下の式（２７）および（２８）のようになる。

It becomes. Here, there are four unknowns, Φ, ψ, a, and b. From these equations, the wrapped value φ of the phase Φ and the wrapped value ψ of ψ are respectively expressed by the following equations (27) and (28 )become that way.

これらの式（２７）および（２８）から、ラッピングされた位相φおよび位相シフト量ψを求めることができる。
なお、式（１３）を解くのに、式（２２）〜（２６）の５つの式を用いたが、未知数の数が４つであるため、この５つの式のうちの４つを用いれば、４つの未知数を求めることができるのは言うまでもない。

From these equations (27) and (28), the wrapped phase φ and the phase shift amount ψ can be obtained.
In order to solve equation (13), five equations of equations (22) to (26) were used, but since the number of unknowns is four, if four of these five equations are used, Needless to say, four unknowns can be obtained.

  Thus, the shape of the measurement target object 21 can be obtained by the optical stepping method.

(Application of all space table method)
By applying the total space table formation method to the above-described shape measurement method of the present invention, the shape measurement of the measurement target object 21 can be performed at higher speed (for example, see JP-A-2008-281491). That is, as shown in FIG. 13, a reference plate 13 having a reference surface 13a on which a two-dimensional lattice arranged parallel to the lattice surface 34a is drawn (or projected) is prepared. The reference plane 13a is photographed while being moved by a predetermined minute amount in the direction, and phase analysis processing is performed on the photographed image, whereby Ψ, Φ, and (Φ _S − The relationship between (Φ _R ) and z is obtained in advance as a table. By referring to the table for each pixel prepared in advance in this way, the value of the height z can be obtained from the phase obtained for each pixel.

In this total space table formation method, it is only necessary to refer to a table for each pixel prepared in advance, and there is almost no need to perform geometric calculation used in triangulation or the like, so that the shape of the measurement target object 21 can be further increased. Can be sought.
Further, in the shape measuring method according to the present invention, various constraint conditions are provided for the arrangement of the light source, the lattice plane, etc., but the brightness distribution of the five LEDs is obtained by the phase analysis using the reference plane 13a. When there is some unevenness, when the point light source is not a perfect point and there is some area, when the one-dimensional grid or LED spacing is not constant but slightly different, the position of the lens of the photographing unit 11 is slightly from the LED surface. The relationship between the measured phase and the height z changes monotonously, such as when each component arranged in parallel deviates slightly from the parallel, or when the luminance distribution of the one-dimensional grating deviates somewhat from the cosine wave. As long as there is a one-to-one correspondence, it is possible to cancel these errors and obtain the shape of the measurement target object 21 with high accuracy.

  In this way, using the shape measurement according to the present invention, the shape of the measurement target object can be measured at high speed and with high accuracy using, for example, the above-described optical stepping method or total space table formation method.

  According to the present invention, by sequentially switching a plurality of LEDs, the phase of the grating projected onto the measurement target object can be shifted at high speed, and the shape of the measurement target object can be measured with high speed and high accuracy. It is useful for inspection, human body measurement, medical care, and stereoscopic observation and stereoscopic measurement of small organisms.

1 Light source 2 Substrate 2a Substrate surface 3 LED
31, 41, 51 the lattice projection light source 32, 42, 52 light source substrate 32a light source substrate surface _{3,33,43,53 L- 2, L- 1, L} 0, L 1, L 2 grid projection LED
4, 34, 44, 54 Grating plate 10, 30, 40, 50 Grating projection unit 11 Imaging unit 12 Analysis control device 13 Reference flat plate 13a Reference plane 21 Measurement target object 32b Recess 32c Convex 34a Lattice surface 45, 55 LED for imaging
100, 200, 300, 400, 500, 600 Shape measuring device U Pixel of imaging device V Center of lens of imaging device

Claims (8)

An apparatus for measuring the shape of an object to be measured,
A light source for lattice projection comprising a light source substrate and a plurality of light emitting diodes for lattice projection arranged on the light source substrate, and a lattice plane on which a one-dimensional lattice is drawn, are arranged in parallel to the light source substrate. A grid projection unit having a grid plate;
An imaging unit that images the measurement target object onto which the one-dimensional lattice is projected;
An analysis device for performing phase analysis processing on the captured image to obtain the shape of the measurement target object;
The shape measuring apparatus is characterized in that each of the plurality of grating projection light emitting diodes is inclined toward the measurement target object with respect to a normal line of the light source substrate.   The shape measuring apparatus according to claim 1, wherein a surface of the light source substrate has a concave portion or a convex portion, and each of the plurality of grating projection light emitting diodes is disposed in the concave portion or the convex portion.   The shape measuring apparatus according to claim 1, wherein the grid projection light source further includes a plurality of imaging light emitting diodes for illuminating the measurement target object.   The shape measuring apparatus according to claim 3, wherein each optical axis of the imaging light emitting diode passes through the lattice plate.   The shape measuring apparatus according to claim 4, further comprising a light diffusion plate between the plurality of imaging light emitting diodes and the lattice plate.   The shape measuring apparatus according to claim 4, wherein an interval between the plurality of imaging light emitting diodes is smaller than an interval between the grid projection light emitting diodes. A substrate and a plurality of light emitting diodes disposed on the substrate;
An optical axis of each of the plurality of light emitting diodes is inclined with respect to a normal line of the substrate.   The light emitting device according to claim 7, wherein a surface of the substrate has a concave portion or a convex portion, and each of the plurality of light emitting diodes is disposed in the concave portion or the convex portion.

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