JP2014181995A - Three-dimensional shape measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional measurement device that enables three-dimensional measurement of a measurement object to be appropriately performed irrespective of magnitude of surface reflectance in the measurement object.SOLUTION: A three-dimensional measurement device 1 comprises: irradiation means 2 capable of changing irradiation intensity of slit light 11 with which a work 10 is irradiated; imaging means 3 for imaging a light cutting line 12 to be formed on a surface of the work 10 by the slit light 11 with which the work 10 is irradiated; and computation means 41 for measuring a three-dimensional shape of the work 10, using an image including the imaged light cutting line 12. The irradiation means 2 irradiates the work 10 by gradually changing the irradiation intensity of the slit light 11, and the imaging means 3 images the light cutting line 12 for each irradiation intensity. The computation means 41 measures the three-dimensional shape of the work 10 for each irradiation intensity, using the image including the light cutting line 12 for each irradiation intensity obtained by the imaging means 3, and calculates an optimal three-dimensional shape of the work 10 on the basis of a three-dimensional shape measurement result for each irradiation intensity.

Description

  The present invention relates to a three-dimensional shape measuring apparatus using an optical cutting method.

  Conventionally, there is a method called an optical cutting method as a non-contact three-dimensional shape measurement method. In such a technique, a thin sheet-like light (hereinafter referred to as “slit light”) by a laser beam or the like is irradiated onto an object to be measured (hereinafter referred to as “work”). A bright line of reflected light (hereinafter referred to as “light cutting line”) is formed on the surface of the work irradiated with the slit light in accordance with its cross-sectional shape. A light cutting line formed on the surface of the workpiece is converted into an electric signal by an image pickup device such as a PSD (Position Sensitive Detector) or an image sensor, and is imaged. Using the principle of triangulation by combining the equation of the line of sight between the optical cutting line formed from this imaged optical cutting line and the imaging sensor and the equation of the plane formed by the slit light and the optical cutting line The optical cutting line, that is, the three-dimensional coordinates of each point on the surface of the workpiece is measured. In addition, a series of measurements of the optical cutting line is performed on the entire workpiece by a method such as translating the entire workpiece with a slide table or scanning slit light using a rotating mirror, and measures the three-dimensional shape of the workpiece. .

  When imaging the light cutting line formed on the surface of the workpiece, it can be applied to workpiece surfaces with various reflectivities, such as metal parts with high reflectivity and specular reflection, and black objects with low reflectivity. Thus, it is necessary to appropriately and reliably extract the formed light section line in order to ensure the accuracy of the three-dimensional object shape measurement.

  The range of luminance that can be measured by the image sensor is limited, and the light cutting line may not be appropriately extracted depending on the combination of the irradiation intensity of the slit light source and the reflectance of the workpiece surface. Specifically, when the slit light with too high irradiation intensity irradiates the workpiece surface with a material with high reflectivity, the brightness of the reflected light reaching the image sensor exceeds the upper limit of the range that can be measured by the image sensor. Therefore, it becomes difficult to extract an appropriate light section line from the captured two-dimensional image. Conversely, when the slit light with too low irradiation intensity irradiates the workpiece surface with a low reflectivity material, the brightness of the reflected light reaching the image sensor falls below the range that can be measured by the image sensor, It becomes difficult to extract an appropriate light section line from the captured two-dimensional image.

  These problems are particularly noticeable on the workpiece surface where multiple materials are mixed, and the irradiation intensity of slit light that can extract an effective light cutting line for a workpiece surface material is different from that of a workpiece surface material having a different reflectance. On the other hand, since it does not function effectively, measurement of the three-dimensional shape of the workpiece becomes difficult, or when the deviation of the reflectance between the workpiece surface materials is significant, measurement itself may be impossible.

  Conventionally, as a method for extracting a light section line in such a captured image, the image data of the captured two-dimensional image is analyzed, and the exposure of the image sensor is adjusted by feedback control according to the analysis result. There is a method to extract the data appropriately and reliably.

  For example, in Patent Document 1, a luminance histogram is created based on image data of a captured two-dimensional image in measurement of a cross-sectional shape in the light section method, and exposure adjustment of the image sensor according to the luminance level is performed by feedback control. A method for appropriately and reliably extracting a light section line by selecting an optimum exposure is described.

  Further, in Patent Document 2, in the measurement of the cross-sectional shape in the light cutting method, based on the image data of a two-dimensional image captured in a plurality of exposure states, the image sensor according to the integrated value of the luminance values of the respective image data. A method is described in which exposure adjustment is performed by feedback control, an optimal exposure is selected, and light cutting lines are extracted appropriately and reliably.

JP 2009-250844 A JP 2009-281815 A

  In measurement of the three-dimensional shape of an object by the light cutting method, when the slit light is irradiated on the work surface, the optimum luminance intensity of the slit light is selected to maximize the measurable luminance range of the image sensor. The accuracy of the extraction of the light cutting line is improved. However, for workpieces composed of multiple materials with different reflectivities, the optimal illumination intensity of the slit light differs depending on the part of the workpiece surface that irradiates the slit light. It is difficult to make accurate measurements.

  The problem of diversity of surface reflectivity due to multiple workpiece materials can be expected to be alleviated by exposure control of the image sensor performed by the methods of Patent Document 1 and Patent Document 2, but the problem is completely overcome. It has not been done. Specifically, in the captured two-dimensional image, the region where the reflected light exceeds the upper limit of the range that can be measured by the image sensor (the exposure of the image sensor needs to be lowered when overexposed) and the reflected light is captured. Patent Document 1 and Patent Document 2 corresponding to adjusting the exposure when both of the regions that are below the measurable range of the element (in the case of underexposure and need to increase the exposure of the image sensor) occur in the same image. In this method, it is extremely difficult to normally extract the light section line.

  In both methods of Patent Document 1 and Patent Document 2, extraction of a light section line is performed based on a two-dimensional image captured by slit light having a single irradiation intensity. As described above, it is difficult for the slit light having a single irradiation intensity to cope with a wide variety of surface reflectivities caused by a mixture of a plurality of workpiece materials. For this reason, in Patent Document 1 and Patent Document 2, there is a possibility that three-dimensional shape measurement cannot be performed properly in the case of a workpiece in which a plurality of materials are mixed.

  The present invention has been made in view of the above-described problems, and appropriately performs three-dimensional measurement of a measurement object regardless of the surface reflectance of the measurement object and its diversity. It is an object to provide a three-dimensional shape measuring apparatus capable of

  In order to achieve the above object, the three-dimensional shape measuring apparatus according to claim 1, an irradiating unit capable of changing an irradiation intensity of slit light irradiated to a measurement object, and the irradiating unit being the measurement target. Using an imaging means for imaging a light cutting line formed on the surface of the measurement object by the slit light irradiated to an object, and a two-dimensional image including the light cutting line imaged by the imaging means A three-dimensional shape measuring apparatus comprising: an arithmetic means for measuring the three-dimensional shape of the measurement object, wherein the irradiation means stepwise irradiates the slit light with respect to the measurement object. Irradiation is performed, the imaging unit images a light cutting line for each irradiation intensity, and the calculation unit uses a two-dimensional image including the light cutting line for each irradiation intensity obtained by the imaging unit. And The three-dimensional shape of the measurement object is measured for each intensity, based on the three-dimensional shape measurement result for each said radiation intensity is characterized by obtaining an optimum three-dimensional shape of the measurement object.

  The three-dimensional shape measurement apparatus according to claim 2, wherein the calculation unit calculates an optimal light section line based on the two-dimensional image including the light section line for each irradiation intensity obtained by the imaging unit. The three-dimensional shape of the measurement object is obtained using the optimum light cutting line.

  The three-dimensional shape measurement apparatus according to claim 3, wherein the irradiation unit scans the measurement object with slit light having a predetermined irradiation intensity, and then applies the predetermined irradiation intensity to the measurement object. It is characterized by scanning slit light with different irradiation intensities.

  The three-dimensional shape measuring apparatus according to claim 4 is characterized in that the irradiation unit scans the measurement object with the slit light while switching the irradiation intensity.

  The three-dimensional shape measurement apparatus according to claim 5, wherein when the luminance of the light cutting line imaged by the imaging unit exceeds an upper limit of an effective luminance value of each pixel of an image obtained by the imaging unit, the light The intensity of the slit light emitted from the irradiation unit is adjusted so that the luminance of the cutting line is less than or equal to the upper limit of the effective luminance value, and the luminance of the light cutting line imaged by the imaging unit is The slit irradiated from the irradiation unit so that the luminance of the light cutting line is equal to or higher than the lower limit of the effective luminance value when the effective luminance value of each pixel of the image obtained by the imaging unit is lower than the lower limit. It is characterized by adjusting the irradiation intensity of light.

  The three-dimensional shape measuring apparatus according to claim 6 is characterized in that the irradiation means uses an infrared laser as the slit light, and the imaging means is provided with a visible light cut filter.

  According to the first aspect of the present invention, the irradiating means irradiates the measurement object with the irradiation intensity of the slit light in a stepwise manner, and the calculating means outputs the light for each irradiation intensity imaged by the imaging means. Based on the three-dimensional shape measurement result of the measurement object for each irradiation intensity measured using the two-dimensional image including the cutting line, the optimum three-dimensional shape is obtained. It is possible to appropriately measure the three-dimensional shape of the measurement object regardless of the variety of surface reflectivity caused by the measurement object formed of the above materials and the brightness of illumination in the measurement environment.

  According to the second aspect of the present invention, the calculating means calculates an optimum light cutting line based on a two-dimensional image including the light cutting line for each irradiation intensity obtained by the imaging means, and the optimum light cutting line. Is used to determine the 3D shape of the measurement object, so that the surface reflectance of the material of the measurement object, and the diversity of surface reflectivity that results from the measurement object being formed of multiple materials, measurement Regardless of the brightness of the environmental lighting, etc., it is possible to reliably extract the light section line and appropriately measure the three-dimensional shape of the measurement object.

  According to the invention described in claim 3, the irradiation means scans the measurement object with slit light having a predetermined irradiation intensity, and then the irradiation intensity different from the predetermined irradiation intensity for the measurement object. Since the slit light is scanned, the surface reflectivity of the material of the measurement object, the diversity of surface reflectivity caused by the formation of the measurement object with multiple materials, the brightness of the illumination in the measurement environment, etc. Regardless of, the three-dimensional shape of the measurement object can be measured more reliably.

  According to the invention described in claim 4, since the irradiation means scans the measurement object while switching the irradiation intensity, the light cutting line can be surely extracted from the captured image by one scanning. The three-dimensional shape of the measurement object can be appropriately measured using the obtained light section line.

  According to the fifth aspect of the present invention, it is possible to automatically calculate an appropriate irradiation intensity of the slit light corresponding to the measurement region and irradiate the surface of the measurement object with the slit light. The cutting line can be reliably extracted, and the three-dimensional shape of the measurement target can be appropriately measured using the obtained light cutting line.

  According to the invention described in claim 6, since the irradiating means uses an infrared laser as the slit light, and the imaging means is provided with a visible light cut filter, it is caused by external factors such as strong ambient light. The optical cutting line can be reliably extracted from the captured image without hindering the measurement of the reflected light from the surface of the measurement object.

It is a schematic diagram showing an example of composition of a three-dimensional shape measuring device concerning a 1st embodiment of the present invention. It is a schematic explanatory drawing for demonstrating the two-dimensional image containing the optical cutting line obtained by an imaging device. It is a flowchart which shows an example of the flow of a process by the three-dimensional shape measuring apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows another example of the flow of a process by the three-dimensional shape measuring apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the flow of the process by the three-dimensional shape measuring apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows an example of the method of the automatic adjustment of the irradiation intensity | strength of slit light.

  Hereinafter, the three-dimensional shape measuring apparatus 1 according to the first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a three-dimensional shape measuring apparatus 1 according to this embodiment is for performing three-dimensional measurement of a measurement object (hereinafter referred to as “workpiece”) 10 using a so-called light cutting method. Thus, the irradiation unit 2, the imaging device 3, and the control device 4 including the calculation unit 41 as the calculation unit are provided.

  The irradiation means 2 is for irradiating the slit light 11 on the workpiece 10. For example, as shown in FIG. 1, the irradiation means 2 is 1 for the laser light source 21 and incident light incident from the laser light source 21. A cylindrical lens (cylindrical lens) 22 that changes only in the axial direction and forms slit light 11 that is a linear beam, a mirror 23 that guides the slit light 11 to the work 10, and the work 10 by rotating the mirror 23. And a scanning mechanism 24 for scanning the slit light 11. As the slit light 11 of the irradiation means 2, for example, an infrared laser or the like can be suitably used. Note that the slit light 11 is not limited to the infrared laser, and any slit light 11 can be used as long as it can irradiate the workpiece 10, and the wavelength and visibility of the light to be irradiated are not limited. The irradiation unit 2 can arbitrarily change the irradiation intensity of the slit light 11 and may be, for example, a laser output unit having a laser transmitter or the like. Further, the irradiation means 12 may have a plurality of laser light sources 21 having different irradiation intensities, and slit light having different irradiation intensities with respect to the workpiece 10 by switching ON / OFF of the plurality of laser light sources 21 respectively. 11 may be irradiated.

  The image pickup device 3 picks up an optical cutting line 12 formed on the surface of the workpiece 10 by the slit light 11 irradiated from the irradiation means 2. For example, a CMOS image sensor, PSD (Position Sensitive Detector) or the like is used. An apparatus, a camera, or the like used as the image sensor can be used. As shown in FIG. 2, the light section line 12 imaged by the imaging device 3 is acquired as a two-dimensional image 13 on the imaging surface of the imaging device. As shown in FIG. 2, the imaging device 3 includes a lens 14 that receives reflected light derived from the surface of the workpiece 10 when the light cutting line 12 is imaged on the imaging surface. Further, the imaging device 3 is set at a position where the rear axis (light receiving axis) is shifted by a predetermined angle with respect to the irradiation direction (light projection axis direction) of the slit light 11 from the irradiation means 2. For example, the imaging device 3 is disposed in such a posture that the portion of the light cutting line 12 formed on the horizontal plane portion of the workpiece 10 is similarly horizontal in the two-dimensional image 13. Further, the imaging device 3 is provided with a visible light cut filter (not shown). By cutting visible light with the visible light visible light cut filter, the surface of the work 10 is caused by external factors such as strong ambient light. It can suppress that the detection of the reflected light from is inhibited. Further, when the two-dimensional image 13 including the light section line 12 is acquired by the imaging device 3, the image data is sent to the control device 4.

  The control device 4 is for controlling each part. For example, the irradiation intensity of the slit light 11 applied to the surface of the work 10 from the irradiation means 2 or the work 10 of the slit light 11 using the scanning mechanism 24 is applied. Controls such as scanning. Further, the calculation unit 41 provided in the control device 4 measures the three-dimensional coordinates of each point on the light cutting line 12 from the two-dimensional image 13 including the light cutting line 12 imaged by the imaging device 3, and this three-dimensional The three-dimensional shape of the workpiece 10 is measured based on the coordinates. That is, the calculation unit 41 is based on the image data of the two-dimensional image 13 captured by the imaging device 3, the position of the irradiation unit 2, the position of the lens center O1 of the light receiving lens 14, and the reflected light from the surface of the workpiece 10. Triangulation by combining the equation of the line of sight between the optical cutting line 12 formed from the incident angle with respect to the imaging device 3 and the imaging device 3 and the equation of the plane formed by the slit light 11 and the optical cutting line 12. The three-dimensional coordinates for each point (irradiation point) on the light cutting line 12 on the surface of the workpiece 10 are calculated using the above principle. That is, the three-dimensional coordinates of each point on the light cutting line 12 become measurement data (position data corresponding to the cross-sectional shape of the workpiece 10) by the calculation unit 41. The contour line as the object of the workpiece 10 is measured by the measurement data for one light cutting line 12.

  Then, the irradiation position of the slit light 11 applied to the workpiece 10 is scanned by the irradiation means 2 controlled by the control device 4, and each irradiation of the slit light 11 to the workpiece 10 is performed by measuring at a predetermined interval of the workpiece 10. A two-dimensional image 13 including the light section line 12 corresponding to the position is obtained. That is, the calculation unit 41 continuously obtains measurement data at each irradiation position of the slit light 11 on the work 10 and combines the obtained data to measure the three-dimensional shape of the work 10.

  Hereinafter, the flow of processing by the three-dimensional shape measurement apparatus 1 according to the first embodiment will be described with reference to the flowchart of FIG. In the three-dimensional shape measuring apparatus 1 according to the first embodiment, as shown in FIG. 1, first, the irradiation means 2 irradiates the surface of the workpiece 10 with the slit light 11 having a predetermined irradiation intensity (S101). Thereby, the optical cutting line 12 is formed in the surface of the workpiece | work 10 according to the cross-sectional shape.

  Next, in the three-dimensional shape measuring apparatus 1, the imaging apparatus 3 acquires a two-dimensional image 13 including the light section line 12 formed on the surface of the workpiece 10 (S102). The two-dimensional image 13 acquired by the imaging device 3 is sent to the calculation unit 41 of the control device 4.

  In the calculation unit 41, the luminance value of the pixel (u, v) is analyzed for the two-dimensional image 13 acquired in S102. That is, when the luminance measured at the pixel (u, v) is within a range that can be measured by the image sensor, the light section line 12 is extracted from the pixel (u, v) and the peripheral region (S103). The method of extracting the light cutting line 12 is not particularly limited, and a conventionally known method can be used. Note that when the luminance measured at the pixel (u, v) exceeds the range that can be measured by the imaging device 3 and appropriate measurement has not been performed, the light in the pixel (u, v) and the surrounding area The cutting line 12 is not extracted, and the data in the area is discarded. That is, it is considered that the imaged light section line 12 does not exist in the pixel (u, v) and the peripheral region. A series of analysis for the pixel (u, v) and extraction of the light section line 12 are performed for all the pixels of the two-dimensional image 13.

  Next, the control device 4 determines whether or not scanning has been performed on all regions of the workpiece 10 (S104). When it is determined that scanning has been performed on all areas of the workpiece 10 (S104: YES), the calculation unit 41 calculates the three-dimensional coordinates of each point on the light section line 12 obtained by the process of S103. The three-dimensional shape of the workpiece 10 is measured based on the three-dimensional coordinates (S105). If it is determined that the entire area of the workpiece 10 has not been scanned (S104: NO), the scanning mechanism 24 scans the workpiece 10 with the slit light 11 (S106). A series of processing from S101 to S103 is repeated until scanning of all the regions is completed (S104: YES).

  In this way, the calculation unit 41 scans the slit light 11 having a predetermined irradiation intensity from the irradiation unit 2 over the entire area of the work 10, thereby generating a two-dimensional image including the light cutting line 12 at each irradiation position. It is possible to measure the three-dimensional shape of the workpiece 10 (S105).

  Next, the control device 4 determines whether or not the three-dimensional shape measurement of the workpiece 10 has been performed using the slit light 11 having all the irradiation intensities set in advance (S107). And when the control apparatus 4 judges that the three-dimensional shape measurement of the workpiece | work 10 was performed using the slit light 11 of all the preset irradiation intensity | strengths (S107: YES), it obtained for every irradiation intensity | strength. Based on the three-dimensional shape measurement result, the optimum three-dimensional shape of the workpiece 10 is measured (S108).

  On the other hand, when the control device 4 determines that the three-dimensional shape measurement is not performed using the slit light 11 having all the preset irradiation intensities (S107: NO), the irradiation intensity of the irradiation unit 2 is The irradiation intensity is changed to a predetermined irradiation intensity different from the predetermined irradiation intensity already used for the three-dimensional shape measurement (S109), and the three-dimensional shape measurement of the workpiece 10 using the slit light 11 having all the predetermined irradiation intensity is completed. Until then, a series of processing from S101 to S105 is repeated to obtain a three-dimensional shape measurement result for each of a plurality of irradiation intensities. Then, based on the three-dimensional shape measurement result obtained for each irradiation intensity, the optimum three-dimensional shape of the workpiece 10 is measured (S108). In S108, by combining a plurality of three-dimensional measurement results with different irradiation intensities of the slit light 11, the light cutting line 12 cannot be extracted because the reflection intensity is too strong or too weak at a specific irradiation intensity, and the tertiary Even under the versatility of the surface material of the workpiece 10 that is not suitable for measuring the original shape, an optimal three-dimensional shape can be measured.

  Further, in the three-dimensional shape measurement apparatus 1 according to the first embodiment of the present invention, three-dimensional shape measurement can be performed by the process shown in the flowchart of FIG. 4 instead of the process shown in FIG. Here, first, the slit light 11 having a predetermined irradiation intensity is irradiated from the irradiation unit 2 to the surface of the work 10 as in the process of FIG. 3 (S201), and the light formed on the surface of the work 10 by the imaging device 3 The two-dimensional image 13 including the cutting line 12 is acquired (S202), and the calculation unit 41 extracts the optical cutting line 12 from the two-dimensional image 13 acquired in S202 (S203).

  Next, the control device 4 determines whether or not extraction (S203) of the light cutting line 12 formed on the surface of the workpiece 10 has been performed using the slit light 11 having all of the preset irradiation intensities (S204). . When the control device 4 determines that the three-dimensional shape measurement of the workpiece 10 has been performed using the slit light 11 having all of the preset irradiation intensities (S204: YES), the control device 4 is extracted for each irradiation intensity. Based on the light cutting line 12, the optimum light cutting line 12 is calculated (S205).

  On the other hand, when it is determined that the light cutting line 12 formed on the surface of the workpiece 10 is not extracted using the slit light 11 having all the irradiation intensities set in advance (S204: NO). Changes the irradiation intensity of the irradiation means 2 to a predetermined irradiation intensity different from the predetermined irradiation intensity already used for the three-dimensional shape measurement (S206), and uses slit light 11 of all the predetermined irradiation intensity. The series of processing from S201 to S203 is repeated until the extraction of the light cutting line 12 (S203) is completed.

  Next, the control device 4 determines whether or not scanning has been performed on all regions of the workpiece 10 (S207). When it is determined that scanning has been performed on all regions of the workpiece 10 (S207: YES), the calculation unit 41 determines the three-dimensional of each point on the optimum light section line 12 obtained by the processing of S205. The coordinates are calculated, and the three-dimensional shape of the workpiece 10 is measured based on the three-dimensional coordinates (S208). If it is determined that the entire area of the workpiece 10 has not been scanned (S207: NO), the scanning mechanism 24 scans the workpiece 10 with the slit light 11 (S209). A series of processing from S201 to S205 is repeated until scanning of all the regions is completed (S207: YES).

  Next, the flow of the process of measuring the three-dimensional shape of the workpiece 10 by the three-dimensional shape measuring apparatus 1a according to the second embodiment will be described with reference to the flowchart of FIG. The three-dimensional shape measurement apparatus 1a according to the second embodiment has substantially the same configuration as the three-dimensional shape measurement 1 according to the first embodiment, and the irradiation method of the slit light 11 of the irradiation unit 2 and The flow of processing by the calculation unit 41 is different.

  In the three-dimensional shape measuring apparatus 1a, first, as in the first embodiment, the irradiation means 2 irradiates the surface of the workpiece 10 with the slit light 11 having a predetermined irradiation intensity (S301), and the imaging device 3 causes the workpiece to be measured. The two-dimensional image 13 including the light cutting line 12 formed on the surface of 10 is acquired (S302), and the calculation unit 41 extracts the light cutting line 12 from the two-dimensional image 13 acquired in S302 (S303).

  Next, the control device 4 determines whether or not scanning has been performed on all regions of the workpiece 10 (S304). When it is determined that scanning has been performed on all areas of the workpiece 10 (S304: YES), the calculation unit 41 calculates the three-dimensional coordinates of each point on the light section line 12 obtained by the process of S303. The three-dimensional shape of the workpiece 10 is measured based on the three-dimensional coordinates (S307). If it is determined that scanning has not been performed on all areas of the workpiece 10 (S307: NO), the irradiation intensity of the irradiation means 2 is a predetermined value used for three-dimensional shape measurement in the current process. In step S305, the scanning beam 24 is scanned with the slit light 11 by the scanning mechanism 24 (S306), and the entire area of the workpiece 10 is scanned. Until the scanning is completed (S304: YES), a series of processing from S301 to S303 is repeated. As the processing of S305 and S306, for example, scanning is performed while alternately switching the slit light 11 having a high irradiation intensity and the slit light 11 having a low irradiation intensity. Thereby, even when the workpiece 10 is formed of a plurality of materials having different surface reflectances, the light section line 12 can be extracted from the two-dimensional image 13 acquired in S302. Note that the change of the irradiation intensity of the slit light 11 is not limited to two steps, and may be changed to a plurality of steps of three or more steps.

  In this way, the calculation unit 41 scans the slit light 11 having a predetermined irradiation intensity from the irradiation unit 2 over the entire area of the work 10, thereby generating a two-dimensional image including the light cutting line 12 at each irradiation position. It is possible to measure the three-dimensional shape of the workpiece 10 (S307). In the first embodiment, the number of extractions of the light cutting line 12 increases according to the number of steps of the predetermined irradiation intensity of the slit light 11, and accordingly, the time required for measuring the three-dimensional shape of the workpiece 10 increases. However, in the second embodiment, since the number of extractions of the light cutting line 12 is not affected by the number of steps of the predetermined irradiation intensity of the slit light 11, the three-dimensional shape of the workpiece 10 can be measured by one scan. As a result, measurement time can be shortened.

  Next, the irradiation intensity of the slit light 11 that can be applied in the acquisition (S102, S202, S302) of the two-dimensional image 13 using the imaging device 3 performed in common in the first and second embodiments is automatically adjusted. The method will be described with reference to the flowchart of FIG.

  First, similarly to S102, S202, and S302, the two-dimensional image 13 is acquired by the imaging device 3 (S401). The control device 4 determines whether or not the maximum luminance of the pixels in the obtained two-dimensional image 13 exceeds the upper limit of the effective luminance value of the image sensor used in the imaging device 3 (S402). When the upper limit of the effective luminance value is exceeded (S402: YES), the control device 4 adjusts the irradiation means 2 and lowers the maximum irradiation intensity of the irradiated slit light 11 so as to be lower than the upper limit of the effective luminance value. (S404). When the upper limit of the effective luminance value is not exceeded (S402: NO), the processing by the control device 4 is not performed.

  Next, the control device 4 determines whether or not the minimum luminance of the pixels in the obtained two-dimensional image 13 is lower than the lower limit of the effective luminance value of the image sensor used in the imaging device 3 (S403). When the effective brightness value is below the lower limit of the effective luminance value (S403: YES), the control device 4 adjusts the irradiation means 2 and increases the minimum irradiation intensity of the irradiated slit light 11 to be equal to or higher than the lower limit of the effective luminance value. (S405). When the lower limit of the effective luminance value is not exceeded (S403: NO), the process by the control device 4 is not performed.

  Regardless of the result of the determination of the effective luminance value of the image sensor with respect to the luminance of the pixels in the image (S402, S403), the two-dimensional image 13 is sent to the calculation unit 41 of the control device 4 after the processing is completed.

  In this way, by adjusting the irradiation means 2 with reference to the highest luminance and the lowest luminance in the two-dimensional image 13, the optimum irradiation intensity of the slit light 11 for extraction of the light cutting line 12 can be automatically set. Can do.

  The embodiment of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the scope of the idea of the present invention.

  The three-dimensional shape measurement apparatus according to the present invention can be effectively used as a technique for measuring a three-dimensional shape of a measurement object having a three-dimensional shape by nondestructive inspection.

DESCRIPTION OF SYMBOLS 1 Three-dimensional shape measuring apparatus 2 Irradiation means 3 Imaging device (imaging means)
41 Calculation unit (calculation means)
10 Workpiece (object to be measured)
11 Slit light 12 Optical cutting line 13 Two-dimensional image

Claims (6)

An irradiation means capable of changing the irradiation intensity of the slit light applied to the measurement object;
Imaging means for imaging a light cutting line formed on the surface of the measurement object by the slit light irradiated to the measurement object by the irradiation means;
A three-dimensional shape measurement apparatus comprising: a calculation unit that measures a three-dimensional shape of the measurement object using a two-dimensional image including the light cutting line imaged by the imaging unit;
The irradiation means irradiates the measurement object by changing the irradiation intensity of the slit light stepwise,
The imaging means images a light cutting line for each irradiation intensity,
The calculation means measures a three-dimensional shape of the measurement object for each irradiation intensity using a two-dimensional image including a light section line for each irradiation intensity obtained by the imaging means, and for each irradiation intensity. An optimal three-dimensional shape of the measurement object is obtained based on the three-dimensional shape measurement result.   The calculation means calculates an optimal light cutting line based on the two-dimensional image including the light cutting line for each irradiation intensity obtained by the imaging means, and uses the optimal light cutting line, 2. The three-dimensional shape measurement apparatus according to claim 1, wherein the three-dimensional shape of the measurement object is obtained.   The irradiation means scans the measurement object with slit light having a predetermined irradiation intensity and then causes the measurement object to scan with slit light having an irradiation intensity different from the predetermined irradiation intensity. The three-dimensional shape measuring apparatus according to claim 1 or 2.   The three-dimensional shape measuring apparatus according to claim 1, wherein the irradiation unit scans the measurement object with the slit light while switching the irradiation intensity.   When the luminance of the light cutting line imaged by the imaging means exceeds the upper limit of the effective luminance value of each pixel of the image obtained by the imaging means, the luminance of the light cutting line is the upper limit of the effective luminance value. The luminance of the light cutting line imaged by the imaging unit is adjusted so that the intensity of the slit light irradiated from the irradiation unit is adjusted so that the effective luminance of each pixel of the image obtained by the imaging unit is as follows: The irradiation intensity of the slit light irradiated from the irradiation unit is adjusted so that the luminance of the light cutting line is equal to or higher than the lower limit of the effective luminance value when the value is lower than the lower limit of the value. The three-dimensional shape measuring apparatus according to claim 1. The irradiation means uses an infrared laser as the slit light,
The three-dimensional shape measuring apparatus according to claim 1, wherein the imaging unit is provided with a visible light cut filter.

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