JP2012154684A - Device for measuring three-dimensional shape and method for measuring three-dimensional shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately calculate the surface shape of a measuring object without mechanically scanning illumination light.SOLUTION: A lighting control part 31 sequentially lights light sources LE one by one. An imaging control part 32 makes an imaging part 20 acquire image data on a measuring object whenever each light source LE is lit. An image data specification part 33 specifies image data whose luminance value becomes the maximum from among all the pieces of image data acquired by the imaging part 20 for each pixel constituting the image data. An inclination calculation part 34 specifies a position of the light source LE lit when each piece of image data is acquired for each piece of image data specified by the image data specification part 33, and calculates an inclination of each measurement position of the measuring object corresponding to each pixel based on the specified position of each light source LE. A surface shape calculation part 35 calculates height of each measurement position AP based on the inclination of each measurement position AP, calculated by the inclination calculation part 34, and calculates the surface shape of a measuring object OB.

Description

  The present invention relates to a technique for measuring the surface shape of a measurement object.

  When a shiny sample such as laser light is irradiated onto a glossy sample, this light is regularly reflected by the sample. If a PSD (Position Sensitive Detector) that can identify the incident position of light is used, the incident angle of light on the sample can be determined from the incident position of the regular reflection light on the PSD, and the inclination of the sample can be determined. Therefore, the angular distribution of the sample can be obtained by scanning the laser beam toward the sample and detecting the reflected light by PSD.

  FIG. 9 is a schematic diagram illustrating the principle of obtaining the surface shape of the measurement object OB using a laser light source and PSD. FIG. 9A shows a case where the surface SF of the measurement object OB is not tilted with respect to the reference plane RS, and FIG. 9B shows that the surface SF of the measurement object OB is only θ relative to the reference plane RS. It shows the case of tilting.

  As shown in FIG. 9A, when the measurement object OB is not tilted, the illumination light L1 is regularly reflected at the measurement position AP and becomes reflected light L2 and enters the PSD. Here, the incident point where the reflected light L2 enters the PSD is IP.

  On the other hand, as shown in FIG. 9B, when the measuring object OB is inclined by θ, the reflected light L2 ′ is shifted by 2θ with respect to the reflected light L2. As a result, the incident point IP ′ of the reflected light L2 ′ is shifted by 2Lθ with respect to the incident point IP.

  Therefore, if 2Lθ is obtained from the PSD measurement result and divided by 2L, the inclination θ of the measurement object OB with respect to the reference plane RS can be obtained. That is, if the deviation of the incident point IP ′ from the incident point IP is known, the inclination θ of the measurement object can be known.

  As a conventional technique using such a principle, Patent Document 1 is known. In Patent Document 1, light emitted from a laser light source is scanned in a line on the plane of an inspection object using a polygon scanner, reflected light from the plane is received by PSD, and the angle of the plane is calculated. An apparatus for inspecting planar anomalies is disclosed. According to this apparatus, it is possible to separate dirt and wrinkles having a height change, which are difficult to be distinguished only by optical intensity.

  Further, although the principle is different from Patent Document 1, Patent Document 2 is known as a technique for obtaining the surface shape of an inspection object. In Patent Document 2, laser light is converged and irradiated on the surface of an inspection object, reflected light from a reflection point is bifurcated by a half mirror, and the branched reflected light is individually received by two PSDs. An apparatus that performs ray tracing from detection signals from each PSD and calculates the position and angle of a reflection point is disclosed.

JP 2008-32669 A JP 2010-85395 A

  However, in both methods of Patent Documents 1 and 2, laser light is mechanically scanned using a polygon mirror. Such mechanical scanning causes a vibration element, causes a deterioration in measurement accuracy, and shortens the life of the apparatus.

  An object of the present invention is to provide a three-dimensional shape measuring apparatus and a three-dimensional shape measuring method capable of accurately obtaining the surface shape of an object to be measured without mechanically scanning illumination light.

  (1) A three-dimensional shape measurement apparatus according to the present invention is a three-dimensional shape measurement apparatus that measures the surface shape of a measurement object, includes a plurality of light sources, and emits illumination light from a plurality of directions to the measurement object. An illumination unit that irradiates, a lighting control unit that sequentially turns on the plurality of light sources, an imaging unit that captures an image of the measurement object and acquires image data of the measurement object, and each light source is turned on An image capturing control unit that causes the image capturing unit to acquire image data of the measurement object, and image data that has a maximum luminance value for each pixel that constitutes the image capturing unit. For each image data specified by the image data specifying unit and the image data specifying unit specified from the inside, a light source position that is turned on when acquiring each image data is specified, and the position of each specified light source position is determined. In each picture And calculating the height of each measurement position based on the inclination of each measurement position calculated by the inclination calculation unit and the inclination calculation unit calculating the inclination of each measurement position of the measurement object corresponding to A surface shape calculation unit for calculating the surface shape of the object.

  According to this configuration, the illumination light is irradiated from a plurality of directions to the measurement target by sequentially turning on the plurality of light sources. Each time the light source is turned on, image data of the measurement object is acquired. Then, image data having the maximum luminance value is specified for each pixel of the imaging unit.

  Here, since each light source is fixed, each image data can be associated with a light source position that is turned on when each image data is acquired. Further, in a certain pixel, the illumination light from the light source that maximizes the luminance value represents the incident light of the specularly reflected light at the measurement position of the measurement object corresponding to the pixel. Since this specularly reflected light is incident on the imaging unit, if the light source position that maximizes the luminance value is known, the normal at the measurement position can be found from the relationship between the light source position and the position of the imaging unit. The slope at the measurement position can be seen from the line. Thereby, the distribution of the inclination of the surface of the measurement object is obtained, and the surface shape of the measurement object can be obtained.

  Therefore, according to this configuration, mechanical scanning of illumination light is not required, and mechanical vibration does not occur, and the surface shape of the measurement object can be measured with high accuracy. In addition, since mechanical vibration does not occur, the life of the apparatus can be extended.

  (2) It is preferable that the illumination unit includes a hemispherical hood that covers the measurement object, and the plurality of light sources are disposed on an inner surface of the hood.

  According to this configuration, since the light source is disposed on the inner surface of the hemispherical hood, it is possible to prevent the measurement object from being irradiated with unnecessary light such as ambient light. Moreover, arrangement | positioning of a some light source becomes easy by arrange | positioning a light source inside a hood. Furthermore, since the hood is hemispherical, the distance from each light source to the object to be measured is substantially equidistant, and the light source that maximizes the luminance value can be accurately identified.

  (3) The measurement object is a flat object having a streak-like uneven shape, and the surface shape calculation unit is arranged in the longitudinal direction of the muscle from the inclination of each measurement position calculated by the inclination calculation unit. It is preferable to obtain a parallel tilt component that faces and calculate the height of each measurement position from the parallel tilt component of each measurement position.

  When a flat object with streak irregularities is adopted as the measurement object, the illumination light irradiated in a direction substantially parallel to the longitudinal direction of the muscle is highly likely to be regularly reflected by the measurement object. The illumination light irradiated in the direction perpendicular to the longitudinal direction of the muscle is highly likely to be irregularly reflected by the measurement object.

  Therefore, when the inclination of each measurement position is divided into a parallel inclination component that is substantially parallel to the longitudinal direction of the muscle and an orthogonal inclination component that is orthogonal to the longitudinal direction of the muscle, the parallel inclination component of the measurement position is compared to the orthogonal inclination component. The inclination can be expressed accurately. Therefore, the surface shape of the measurement object can be accurately calculated by using only the parallel tilt component.

  (4) It is preferable that the plurality of light sources be arranged so that illumination light directed in the longitudinal direction of the muscle has a higher density than illumination light directed in a direction orthogonal to the longitudinal direction of the muscle.

  According to this configuration, since the illumination light directed in the longitudinal direction of the streak becomes dense, it is possible to accurately obtain a parallel tilt component that is important in measuring a streak-like concavo-convex object. Can be obtained accurately. In addition, the number of light sources can be reduced by sparse light sources arranged on meridians facing in the orthogonal direction.

  (5) The surface shape calculation unit includes a parallel inclination component facing the longitudinal direction of the muscle from the inclination of each measurement position calculated by the inclination calculation unit, and an orthogonal inclination facing an orthogonal direction orthogonal to the longitudinal direction of the muscle. It is preferable to calculate the height of each measurement position from the parallel tilt component and the orthogonal tilt component of each measurement position.

  According to this configuration, when an object having an arbitrary shape is adopted as the measurement object, the surface shape of the measurement object can be calculated with high accuracy.

  According to the present invention, the illumination light does not need to be mechanically scanned, no mechanical vibration is generated, and the surface shape of the measurement object can be accurately measured. In addition, since mechanical vibration does not occur, the life of the apparatus can be extended.

1 is a block diagram of a three-dimensional shape measuring apparatus according to Embodiment 1 of the present invention. It is a block diagram of the illumination part seen from the Z-axis direction. FIG. 3 is a layout diagram of light sources shown in FIG. 2. It is explanatory drawing of the principle of the three-dimensional shape measuring apparatus by embodiment of this invention, (A) is a side surface schematic diagram of the three-dimensional shape measuring apparatus by this embodiment, (B) is imaged by the imaging part. FIG. 6C is a schematic diagram of the image data, and FIG. 8C is an enlarged view of a portion surrounded by a dotted line in FIG. It is the figure which showed an example of the surface shape of the measuring object displayed by the display part. It is a flowchart which shows operation | movement of the three-dimensional shape measuring apparatus by embodiment of this invention. It is a flowchart which shows operation | movement of the three-dimensional shape measuring apparatus in Embodiment 2 of this invention. It is a layout view of the light source according to the third embodiment of the present invention. It is a schematic diagram which shows the principle which calculates | requires the surface shape of a measuring object using a laser light source and PSD.

(Embodiment 1)
Hereinafter, a three-dimensional shape measuring apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a three-dimensional shape measuring apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the three-dimensional shape measuring apparatus measures the surface shape of a measurement object, and includes an illumination unit 10, an imaging unit 20, a control unit 30, a display unit 40, and an image memory 50. .

  In the present embodiment, a flat plate-like object having periodic streaky irregularities is employed as the measurement object. Specifically, the measuring object is a flat object obtained by rolling a metal such as aluminum or iron. Therefore, the line-like uneven shape is a rolling stripe generated when rolling. Here, the measurement object is obtained, for example, by transporting a metal between a pair of rolling rollers. Accordingly, the streaks have an uneven shape whose longitudinal direction is substantially parallel to the metal transport direction.

  The illumination unit 10 includes a plurality of light sources and irradiates the measurement target with illumination light from a plurality of directions. FIG. 2 is a configuration diagram of the illumination unit 10 viewed from the Z-axis direction. The Z axis is orthogonal to the reference plane on which the measurement object OB is placed. Further, both the X axis and the Y axis are orthogonal to each other. Further, the origin of the X, Y, and Z axes is set as the center OF of the hood 11 that is a projection point on the reference plane of the vertex OC of the hood 11 (see FIG. 4A). In the present embodiment, the measurement object is placed directly below the vertex OC so that the longitudinal direction of the muscle faces the Y direction.

  The illumination unit 10 includes a hemispherical hood 11 having a predetermined diameter. On the inner surface of the hood 11, a plurality of light sources LE are radially arranged around the center OF of the hood 11.

  The light source LE is composed of, for example, a light emitting diode, is electrically connected to the control unit 30 via a wiring cord, and is turned on and off under the control of the lighting control unit 31. In the present embodiment, the number of light sources LE is N (for example, 192).

  The hood 11 is arranged such that the vertex OC is located immediately above the center of the measurement object and covers the measurement object. Of course, the diameter of the hood 11 is longer than the total length of the measurement object. Thus, by arranging the light source LE on the inner surface of the hood 11, the distance between each light source LE and the measurement object can be made substantially equal. Further, the provision of the hood 11 facilitates the arrangement of the light source LE. Further, since the hood 11 is hemispherical, the measurement object can be completely shielded from the reference surface on which the measurement object is placed, and the measurement object is irradiated with light such as ambient light. This can be prevented.

  FIG. 3 is a layout diagram of the light source LE shown in FIG. In the hood 11, the light source LE is not arranged in a substantially circular area having a radius r0 from the vertex OC. This is because the imaging unit 20 is attached in this circular area. Even if the illumination light is irradiated from directly above the measurement object, it is unlikely that the illumination light will be regularly reflected by the measurement object. Therefore, there is no problem even if the light source LE is not arranged in the circular area. Absent. Thereby, the number of the light sources LE can be reduced as compared with the case where the light sources LE are arranged in the entire area of the hood 11.

  A plurality of meridian Lt is set on the inner surface of the hood 11 around the vertex OC, and the light source LE is disposed on the meridian Lt. In the example of FIG. 3, the meridian Lt is set at intervals of 15 degrees with the vertex OC as the center. Therefore, the light sources LE are arranged at azimuth angles φ of 15 degrees.

  Assuming that the projection point of the vertex OC on the reference plane (the center of the opening surface of the hood 11) is the center OF of the hood 11, the light source LE is centered on the center OF at a predetermined angular interval (in the example of FIG. 7.5 degrees). In FIG. 3, the light sources LE become denser from the vertex OC toward the outside because the hemispherical hood 11 is viewed from the inside.

  In the present embodiment, the light source position of the light source LE is defined by the azimuth angle φ and the elevation angle θ. The azimuth angle φ is an angle formed between the meridian Lt where the light source LE is arranged and the X axis when viewed from the Z-axis direction. The elevation angle θ is an angle formed by a straight line connecting the light source LE and the center OF and the Z axis (see FIG. 4A).

  Returning to FIG. 1, the imaging unit 20 includes, for example, an area sensor in which a plurality of pixels are arranged in a matrix of predetermined rows × predetermined columns, images the measurement object from the Z direction, and obtains image data of the measurement object. get. Specifically, as shown in FIG. 4A, the area sensor 21 is arranged inside the housing 22 so that the light receiving surface is orthogonal to the Z direction. In addition, the imaging unit 20 includes an optical system (not shown) that forms an optical image of the measurement object on the area sensor 21. Here, the imaging unit 20 stores the light source number that identifies the light source LE that is turned on when acquiring the image data and the image data in the image memory 50 in association with each other.

  Returning to FIG. 1, the control unit 30 includes a microcomputer including a CPU, a ROM, a RAM, and the like, or a dedicated hardware circuit, and controls the entire three-dimensional shape measuring apparatus. In the present embodiment, the control unit 30 includes a lighting control unit 31, an imaging control unit 32, an image data specifying unit 33, an inclination calculation unit 34, a surface shape calculation unit 35, and a display control unit 36.

  The lighting control unit 31 sequentially turns on the light sources LE one by one. Here, the lighting order of the light sources LE is determined in advance, and the lighting control unit 31 sequentially lights the light sources LE according to the lighting order.

  The imaging control unit 32 causes the imaging unit 20 to acquire the image data of the measurement target each time each light source LE is turned on, and causes the image memory 50 to store the acquired image data. In the present embodiment, since there are 192 light sources LE, 192 pieces of image data are acquired by the imaging unit 20.

  The image data specifying unit 33 specifies one piece of image data having the maximum luminance value from all the image data acquired by the imaging unit 20 for each pixel constituting the area sensor 21.

  For each image data specified by the image data specifying unit 33, the inclination calculating unit 34 specifies the position of the light source LE that is turned on when acquiring each image data, and based on the specified position of each light source LE. The inclination of each measurement position of the measurement object corresponding to each pixel is calculated.

  FIG. 4 is an explanatory diagram of the principle of the three-dimensional shape measuring apparatus according to the embodiment of the present invention, (A) is a schematic side view of the three-dimensional shape measuring apparatus according to the present embodiment, and (B) is an image pickup. It is a schematic diagram of the image data imaged by the part 20, (C) is an enlarged view of the part enclosed with the dotted line of (A).

  As shown in FIG. 4B, for example, the upper left vertex of the image data is the origin, the m axis is set in the horizontal direction, and the n axis is set in the vertical direction. The image data shown in FIG. 4B is image data that maximizes the luminance value of a certain pixel G (m, n). The light source number i is associated with the image data shown in FIG. 4B, and the light source LE (i) that is turned on when the image data is acquired is shown in FIG.

  When the luminance value of the pixel G (m, n) is maximized, the specularly reflected light of the light source LE (i) is incident on the imaging unit 20. Therefore, as shown in FIG. 4C, the illumination light L1 (i) emitted from the light source LE (i) is regularly reflected at the measurement position AP on the surface of the measurement object OB, and is reflected light parallel to the Z axis. L <b> 2 (i) enters the imaging unit 20. Since the arrival position of the reflected light L2 (i) on the light receiving surface of the area sensor 21 is the pixel G (m, n), the pixel (m, n) corresponds to the measurement position AP.

  The azimuth angle of the light source LE (i) is φ (i) and the elevation angle is θ (i). The U axis is a straight line that passes through the center OF and forms an angle of φ (i) with the X axis. Therefore, the shape of the measurement object OB shown in FIG. 4A shows a cross section cut along the U axis.

  As shown in FIG. 4C, the illumination light L1 (i) is regularly reflected at the measurement position AP to become reflected light L2 (i), so that the bisector LM (i) of θ (i) is , Perpendicular to the tangent line SL in the U-axis direction at the measurement position AP. Therefore, the inclination ψ (i) of the tangent SL with respect to the reference plane RS is represented by ψ (i) = θ (i) / 2. Therefore, the inclination ψ (i) of the measurement position AP corresponding to the pixel G (m, n) is calculated as ψ (i) = θ (i) / 2. When this process is performed for all the pixels constituting the area sensor 21, the inclination of the measurement position AP corresponding to each pixel can be obtained.

  Returning to FIG. 1, the surface shape calculation unit 35 calculates the height of each measurement position AP based on the inclination of each measurement position AP calculated by the inclination calculation unit 34, and calculates the surface shape of the measurement object OB. To do.

  In the present embodiment, the surface shape calculation unit 35 uses the equation (1) to calculate an inclination component ψ_X (i) (an example of an orthogonal inclination component) and an inclination component ψ_Y (i) (parallel inclination) from the inclination of each measurement position AP. An example of a component).

ψ_X (i) = − tan (θ (i) / 2) · cos φ
ψ_Y (i) = − tan (θ (i) / 2) · sinφ (1)
As shown in FIG. 4A, the inclination ψ (i) obtained by the inclination calculating unit 34 is an inclination on the U axis. The angle formed by the U axis and the X axis is φ (i), and the X axis and the Y axis are orthogonal to each other. Therefore, the inclination component ψ_X (i) and the inclination component ψ_X (i) are expressed by Expression (1).

  Here, ψ_X (i) and ψ_Y (i) are obtained for each measurement position AP, and each measurement position AP corresponds to each pixel G (m, n). ) Can also be expressed as ψ_X (m, n), ψ_Y (m, n). Hereinafter, ψ_X (i) and ψ_Y (i) are expressed using (m, n) as necessary.

  Next, the surface shape calculation unit 35 obtains an inclination component ψ_X (m, n) and an inclination component ψ_Y (m, n) using Equation (1) for each measurement position AP. Then, the surface shape calculation unit 35, for example, sets the height H (0, 0) of the pixel G (0, 0) of (m, n) = (0, 0) to a predetermined height (eg, 0). Set to. Then, using the gradient component ψ_X (0,0) obtained by the equation (1), the pixel resolution ΔX of the predetermined X component, and the height H (0,0), the equation (2) is obtained. Thus, the height H (1,0) at (m, n) = (1,0) is obtained.

H (1,0) = H (0,0) + ψ_X (0,0) · ΔX (2)
Next, the surface shape calculation unit 35 uses the equation (2) ′ from H (1, 0) obtained in Equation (2), and uses the pixel G ( The height H (2, 0) of (2, 0) is obtained.

H (2,0) = H (1,0) + ψ_X (1,0) · ΔX (2) ′
Thereafter, the surface shape calculation unit 35 calculates the height H (m, 0) in the row of n = 0 as H (3, 0), H (4, 0), H (5, 0). ) In turn.

  And the surface shape calculation part 35 will calculate inclination component (psi) _Y (0, 0) calculated | required by Formula (1), and Y previously determined, if all the height H (m, 0) in the row | line of n = 0 is calculated. Using the pixel resolution ΔY of the component and the height H (0, 0), the height H (0, 1) at (m, n) = (0, 1) is expressed as shown in Equation (3). Ask.

H (0,1) = H (0,0) + ψ_Y (0,0) · ΔY (3)
Then, the surface shape calculation unit 35 performs H = 1, H (2, 1), H (3, 1)..., N = 1, similarly to the row of n = 0. The height H (m, 1) in the row is sequentially obtained.

  In this way, the surface shape calculation unit 35 sequentially obtains the height H (m, n) corresponding to (m, n) line by line, and all the measurement positions AP on the surface of the measurement object OB. The height H (m, n) of is calculated.

  The display control unit 36 uses a height H (m, n) of each measurement position AP calculated by the surface shape calculation unit 35 to virtually represent a three-dimensional model that three-dimensionally represents the surface shape of the measurement object OB. Generate in 3D space. Then, the display control unit 36 renders the three-dimensional model using the position information of the virtual camera and the virtual light source in the virtual three-dimensional space, writes the obtained two-dimensional image data in the frame buffer, and causes the display unit 40 to display it. . The display control unit 36 may cause the user to set the position information of the virtual camera and the virtual light source, and display the surface shape of the measurement object OB when viewed from various lines of sight on the display unit 40.

  The display unit 40 is configured by a display device such as a liquid crystal display or an organic EL display, and displays the two-dimensional image data generated by the display control unit 36. The image memory 50 is configured by a non-volatile storage device such as a hard disk, and stores image data captured by the imaging unit 20.

  FIG. 5 is a diagram illustrating an example of the surface shape of the measurement object OB displayed by the display unit 40. As shown in FIG. 5, it can be seen that the measurement object OB has a shape in which streaky unevenness is periodically repeated. This uneven | corrugated shape is produced | generated when rolling the measuring object OB. In addition, streak is disturbed in a region KZ surrounded by a circle at the center of the drawing. The disturbance of the streaks is a rolling bar, and the three-dimensional shape measuring apparatus according to the present embodiment aims to detect the rolling bar. Thereby, the user can confirm the rolling bar at a glance and can detect an abnormal portion of the measurement object OB.

  FIG. 6 is a flowchart showing the operation of the three-dimensional shape measuring apparatus according to the embodiment of the present invention. Before this flowchart is executed, first, the measurement object OB is placed on the reference plane by the user, and the illumination unit 10 is placed on the reference plane so that the vertex OC of the hood 11 is positioned directly above the center. Is done. Then, the user inputs an instruction to start measurement via an operation unit (not shown), and the following processing is executed.

  In step S1, the light source number i is set to 1, which is an initial value. In the present embodiment, since the light sources LE are turned on according to a predetermined lighting order, a light source number corresponding to the lighting order is assigned to each light source LE in advance.

  Various orders can be adopted as the lighting order, but it is preferable to sequentially turn on the adjacent light sources LE from the viewpoint of simplifying the lighting control. For example, in FIG. 3, first, the light source LE with the azimuth angle φ = 0 is sequentially turned on in the range of the elevation angle θ = −90 degrees to +90 degrees, and then the light source LE with the azimuth angle φ = 15 degrees is A lighting order may be employed in which the lighting is sequentially performed in the range of the elevation angle θ = −90 degrees to +90 degrees.

  Next, the lighting control unit 31 turns on the light source LE (i) (step S2). Thereby, the measurement object OB is irradiated with illumination light from the light source LE (i). Next, the imaging control unit 32 causes the imaging unit 20 to image the measurement object OB irradiated with the illumination light, and acquires one piece of image data D (i) (step S3).

  Next, the imaging control unit 32 stores the image data D (i) in the image memory 50 in association with the azimuth angle φ (i) and the elevation angle θ (i) of the light source LE (i) (step S4). Here, the imaging control unit 32 stores in advance the relationship between the light source number i, the azimuth angle φ (i), and the elevation angle θ (i), and uses this relationship to associate the azimuth angle with the image data D (i). φ (i) and elevation angle θ (i) may be determined.

  Next, the lighting control unit 31 determines whether or not the light source number i is greater than N (= 192). If i> N (YES in step S5), the process proceeds to step S7. On the other hand, if i ≦ N (NO in step S5), the lighting control unit 31 increments the light source number i by 1 (step S6), and returns the process to step S2. That is, the lighting control unit 31 repeats the processes of steps S2 to S6 until all N light sources LE are turned on, and each time one light source LE is turned on, one image data is stored in the imaging unit 20. D (i) is imaged. When all N light sources LE are turned on and N pieces of image data D (i) are obtained, the process proceeds to step S7.

  Next, the image data specifying unit 33 converts one piece of image data D (i) having the maximum luminance value into N pieces of image data D for each of all the pixels G (m, n) constituting the area sensor 21. (I) is specified (step S7). Next, the inclination calculating unit 34 specifies the azimuth angle φ (i) and the elevation angle θ (i) associated with the image data D (i) specified in step S7 (step S8). Thereby, the azimuth angle φ (i) and the elevation angle θ (i) of the illumination light regularly reflected at each measurement position AP corresponding to each pixel G (m, n) are specified.

  Next, the inclination calculating unit 34 divides the elevation angle θ (i) specified for each measurement position AP in step S8 by 2, and, as shown in FIG. 4C, the inclination ψ ( i) is calculated (step S9). Thereby, the inclination ψ (m, n) of the measurement position AP corresponding to each pixel G (m, n) is obtained, and the distribution of the inclination of the surface of the measurement object OB is obtained.

  Next, the surface shape calculation unit 35 uses the above equation (1) based on the inclination ψ (m, n) obtained in step S9, and the inclination component ψ_X (m, n) and the inclination component ψ_Y (m, n). ) Is obtained (step S10).

  Next, the surface shape calculation part 35 calculates | requires the height H (m, n) of each measurement position AP sequentially using said Formula (2), (3) etc. (step S11).

  Thus, according to the present embodiment, the direction of the illumination light is switched by sequentially lighting the light sources LE arranged radially on the inner surface of the hood 11. Therefore, mechanical scanning of illumination light becomes unnecessary, mechanical vibration does not occur, and the surface shape of the measurement object can be measured with high accuracy. In addition, since mechanical vibration does not occur, the life of the apparatus can be extended.

(Embodiment 2)
The three-dimensional shape measuring apparatus according to the second embodiment is characterized in that the height H (m, n) is calculated using only the inclination component ψ_Y (m, n). In the present embodiment, the same elements as those in the first embodiment are not described.

  FIG. 7 is a flowchart showing the operation of the three-dimensional shape measuring apparatus according to Embodiment 2 of the present invention. Since the process of step S21-S29 is the same as step S1-S9 of FIG. 6, description is abbreviate | omitted.

  In step S30, the surface shape calculation unit 35 calculates only the inclination component ψ_Y (m, n) in the Y direction that goes in the longitudinal direction of the muscle of the measurement object OB, as in the first embodiment, and ψ_X (m , N) is not calculated. That is, the surface shape calculation unit 35 calculates ψ_Y (m, n) using ψ_Y (i) = − tan (θ (i) / 2) · sinφ.

  Next, the surface shape calculation unit 35 calculates the height H (m, n) of each measurement position AP using ψ_Y (m, n) obtained in step S30 (step S31).

  Here, for example, the surface shape calculation unit 35 sets the height H (m, 0) of each position of the top row n = 0 to a predetermined height (eg, 0). . Then, using the inclination component ψ_Y (0, n) at each position of the column of m = 0 obtained in step S30, the pixel resolution ΔY of the predetermined Y component, and the height H (0, 0). As shown in the following equation, the height H (0, n) of each position of the column of m = 0 is obtained in order from n = 1 downward.

H (0,1) = H (0,0) + ψ_Y (0,0) · ΔY
H (0,2) = H (0,1) + ψ_Y (0,1) · ΔY
...
Then, when the surface shape calculation unit 35 calculates the height H (0, n) of each position of the column of m = 0, as shown in the following formula, the height H ( 1, n) is calculated in order from n = 1 downward.

H (1,1) = H (1,0) + ψ_Y (1,0) · ΔY
H (1,2) = H (1,0) + ψ_Y (1,0) · ΔY
...
Thereafter, the height H (m, 1), H (m, 2),... Of each position is obtained in order from n = 1 using the following formula for an arbitrary m column.

H (m, 1) = H (m, 0) + ψ_Y (m, 0) · ΔY
H (m, 2) = H (m, 1) + ψ_Y (m, 1) · ΔY
...
Thus, the height H (m, n) of all measurement positions AP on the surface of the measurement object OB is obtained, and the surface shape of the measurement object OB is calculated.

  When a flat object having a streak-like uneven shape is adopted as the measurement object OB, the illumination light irradiated in a direction substantially parallel to the longitudinal direction of the stripe is highly likely to be regularly reflected by the measurement object OB. However, the illumination light irradiated in the direction orthogonal to the longitudinal direction of the muscle is highly likely to be irregularly reflected by the measurement object OB.

  Therefore, the inclination of each measurement position AP is changed into an inclination component ψ_Y (m, n) in the Y-axis direction substantially parallel to the longitudinal direction of the muscle and an inclination component ψ_X (m, n) in the X-axis direction orthogonal to the longitudinal direction. When divided, the inclination component ψ_Y (m, n) can accurately represent the inclination of each measurement position AP as compared with the inclination component ψ_X (m, n). Therefore, the surface shape of the measurement object OB can be accurately calculated by using only the inclination component ψ_Y (m, n).

  In the present embodiment, it is not necessary to calculate the inclination component ψ_X (m, n), so that the calculation cost can be reduced. That is, in this embodiment, it is possible to achieve both the effect of reducing the calculation cost and the effect of conflicting with the effect of improving the measurement accuracy.

(Embodiment 3)
In the three-dimensional shape measuring apparatus according to Embodiment 3, the light source LE is arranged so that the illumination light directed in the Y-axis direction, which is the longitudinal direction of the measurement object OB, has a higher density than the illumination light directed in the X-axis direction. It is characterized by that. FIG. 8 is a layout diagram of the light source LE according to the third embodiment of the present invention. FIG. 8 shows the arrangement of the light sources LE when the hood 11 is viewed from the inside.

  In the example of FIG. 8, the meridian Lt (0) on the Y axis, the meridians Lt (1), Lt (−1) having an angle with respect to the meridian Lt (0) and the vertex OC, for example, 15 degrees, and the meridian Lt (0 ) And the meridians Lt (2) and Lt (−2) whose angles with respect to the vertex OC are 30 degrees, for example, the same number of light sources LE are arranged. Further, in the meridian Lt (X) on the X axis, the same number of light sources LE as the meridian Lt (1) are arranged.

  Here, the illumination light directed in the longitudinal direction of the stripe corresponds to illumination light whose optical axis is within a range of ± 45 degrees from the Y axis with the vertex OC as the center. Further, the illumination light directed in the orthogonal direction corresponds to illumination light whose optical axis is in the range of ± 45 degrees around the X axis with the vertex OC as the center.

  In this way, since the illumination light directed in the longitudinal direction of the muscle becomes dense, the inclination component ψ_Y (m, n) that is important in measuring the measurement object OB having the stripe-shaped uneven shape is accurately obtained. The height H (m, n) of each measurement position AP can be accurately obtained. On the other hand, since the number of the light sources LE arranged on the meridian Lt facing in the X-axis direction can be reduced, the apparatus can be simplified and the cost can be reduced.

  In the present embodiment, the number of light sources LE arranged on each meridian Lt is the same. However, the present invention is not limited to this. For example, the density of the light sources LE may be increased toward the Y axis. For example, in FIG. 8, the meridian Lt (0) has the highest density, the meridians Lt (1) and Lt (-1) have the next highest density, and the meridians Lt (2) and Lt (-2) have the next highest density. The light source LE may be arranged so that Further, the number of light sources arranged on the meridian Lt (X) may be zero. However, in this case, there is a concern that the number of light sources LE belonging to the region D2 becomes zero, the illumination light component toward the X-axis direction becomes zero, and the measurement accuracy decreases. Therefore, in the example of FIG. 8, the light source LE is disposed only on one meridian Lt (X).

  In Embodiment 3, since the illumination light whose optical axis is in the Y-axis direction is dense, the tilt component ψ_Y (m, n) can be calculated with high accuracy, but the illumination light whose optical axis is in the X-axis direction is Since it becomes sparse, the accuracy of the tilt component ψ_X (m, n) may be deteriorated. Therefore, when the arrangement of the light source LE of the third embodiment is employed, the height H (m, n) of each measurement position AP is obtained using only the inclination component ψ_Y (m, n) shown in the second embodiment. preferable. That is, by combining Embodiment 3 and Embodiment 2, the effect of reducing the number of light sources LE in Embodiment 2 can be obtained.

  In the first to third embodiments, an object having periodic streaky irregularities is employed as the measurement object OB. However, the present invention is not limited to this, and an object having an arbitrary shape is employed. May be.

DESCRIPTION OF SYMBOLS 10 Illumination part 11 Hood 20 Imaging part 21 Area sensor 22 Case 30 Control part 31 Lighting control part 32 Imaging control part 33 Image data specific part 34 Inclination calculation part 35 Surface shape calculation part 36 Display control part 40 Display part 40 Image memory AP Measurement position D1 area D2 area G pixel L1 illumination light L2 reflected light LE light source Lt meridian OB measurement object OC vertex θ elevation angle ψ inclination ψ_X X component of inclination ψ_Y Y component of inclination

Claims (6)

A three-dimensional shape measuring apparatus for measuring the surface shape of a measurement object,
An illumination unit that includes a plurality of light sources and irradiates the measurement object with illumination light from a plurality of directions;
A lighting control unit for sequentially lighting the plurality of light sources;
An imaging unit that images the measurement object and acquires image data of the measurement object;
An imaging control unit that causes the imaging unit to acquire image data of the measurement target each time each light source is turned on,
For each pixel constituting the imaging unit, an image data specifying unit that specifies image data having a maximum luminance value from among all image data acquired by the imaging unit;
For each image data specified by the image data specifying unit, a light source position that is turned on when each image data is acquired is specified, and based on each specified light source position, the measurement object corresponding to each pixel is identified. An inclination calculator for calculating the inclination of each measurement position;
A three-dimensional shape measurement apparatus comprising: a surface shape calculation unit that calculates a height of each measurement position based on the inclination of each measurement position calculated by the inclination calculation unit and calculates a surface shape of the measurement object. The illumination unit includes a hemispherical hood that covers the measurement object,
The three-dimensional shape measuring apparatus according to claim 1, wherein the plurality of light sources are disposed on an inner surface of the hood. The measurement object is a flat object having a streaky uneven shape,
The surface shape calculation unit obtains a parallel inclination component facing the longitudinal direction of the muscle from the inclination of each measurement position calculated by the inclination calculation unit, and calculates the height of each measurement position from the parallel inclination component of each measurement position. The three-dimensional shape measuring apparatus according to claim 1 or 2, wherein the three-dimensional shape measuring apparatus calculates.   The three-dimensional shape according to claim 3, wherein the plurality of light sources are arranged such that illumination light directed in a longitudinal direction of the muscle has a higher density than illumination light directed in a direction orthogonal to the longitudinal direction of the muscle. Measuring device.   The surface shape calculation unit includes a parallel inclination component that faces the longitudinal direction of the muscle from an inclination of each measurement position calculated by the inclination calculation unit, and an orthogonal inclination component that faces an orthogonal direction perpendicular to the longitudinal direction of the muscle. The three-dimensional shape measuring apparatus according to claim 1 or 2, wherein the height of each measurement position is calculated from the parallel inclination component and the orthogonal inclination component of each measurement position. A three-dimensional shape measurement method for measuring the surface shape of a measurement object,
An illumination unit including a plurality of light sources illuminates the measurement object with illumination light from a plurality of directions, and
An imaging step in which the imaging unit acquires image data of the measurement object to the imaging unit each time each light source is turned on,
For each pixel constituting the image data, an image data specifying step for specifying image data having a maximum luminance value from all the image data acquired by the imaging step;
For each image data specified in the image data specifying step, the light source position turned on when each image data is acquired is specified, and each pixel is supported based on the specified light source position and the position of the imaging unit. An inclination calculating step for calculating an inclination of each measurement position of the measurement object;
A three-dimensional shape measurement method comprising: a surface shape calculation step of calculating a height of each measurement position based on the inclination of each measurement position calculated by the inclination calculation step and calculating a surface shape of the measurement object.