JP2008281391A - Apparatus and method for measuring three-dimensional shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure the shapes of objects to be measured even if the objects to be measured has different reflectances according to location in the case of measuring the three-dimensional shape of the object to be measured by a phase shift method. <P>SOLUTION: A three-dimensional shape measuring apparatus 1 irradiates light having a plurality of strengths to an object to be measured OB, forms fringe patterns on the object to be measured OB for every light of each strength, and computes a phase value and evaluation data on the basis of the formed fringe patterns for every case of irradiating light having a plurality of strengths. A phase value computed in the case of irradiating light having a strength most corresponding to a reflectance at the location of irradiation of irradiation light is selected from phase values computed in the case of irradiating the irradiation light having each strength by evaluating the evaluation data. By measuring the three-dimensional shape of the object to be measured OB through the sue of a phase value selected in this way, it is possible to prevent or reduce degradation of measurement accuracy of three-dimensional shape data due to reflectance changes of the object to be measured OB. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention irradiates the object to be measured with striped irradiation light composed of a bright part and a dark part, and changes the phase at each location of the striped pattern formed on the object to be measured by this irradiation light. The present invention relates to a three-dimensional shape measuring apparatus and a three-dimensional shape measuring method for measuring a three-dimensional shape of a measurement object by receiving reflected light.

  There are many methods for measuring the three-dimensional shape of the measurement object in a non-contact manner. Among them, for example, a three-dimensional shape measurement method based on a phase shift method disclosed in Patent Document 1 is known. Further, the Fourier transform phase shift method using Fourier transform when calculating the phase has an advantage that the measurement accuracy can be further improved because the phase value can be calculated with high accuracy by removing noise.

  FIG. 8 is a schematic diagram of a three-dimensional shape measuring apparatus that measures the three-dimensional shape of the measurement object by the phase shift method. According to this three-dimensional shape measuring apparatus, the controller 50 outputs an emission command to the irradiation device 11 of the three-dimensional sensor 10 in accordance with an input instruction from an operator via the input device 52. In response to this command, light is emitted from the irradiation device 11. The light emitted from the irradiation device 11 is transmitted through a liquid crystal or a slide having a striped pattern, or the light from the light source is split into two lights so that each light interferes with different optical path differences. By this method, it is set as the striped light by which the bright part and the dark part were repeated alternately, and such a striped light is irradiated to the measuring object OB. For this reason, a striped pattern is formed on the surface of the measurement object OB in which the bright part and the dark part are repeated at regular intervals. In this way, the phase at each part of the striped pattern (hereinafter referred to as the fringe phase) is shifted by moving the formation site of the striped pattern formed on the measurement object OB by a minute distance in a direction perpendicular to the line direction of the striped line. The reflected light from the measurement object OB is received by the light receiving device 12 at a predetermined movement position. The light receiving device 12 outputs a light reception signal to the data processing device 30, and the data processing device 30 creates three-dimensional shape data of the measurement object OB based on the calculation by the phase shift method. Then, the three-dimensional shape of the measurement object OB is displayed on the display device 54.

  FIG. 9A is a diagram showing a stripe pattern formed on the liquid crystal or the slide. As shown in FIG. 9 (a), the stripe pattern has a sine wave shape drawn along the direction perpendicular to the line direction of each stripe. That is, the luminance distribution along the direction perpendicular to the line direction of each stripe in the stripe pattern has a sine wave shape with a constant amplitude as shown in FIG. However, when the measurement object OB is irradiated with irradiation light reflecting such a striped pattern, the intervals between the stripes formed on the measurement object OB due to the unevenness of the measurement object OB are not uniform. Becomes a distorted shape. Therefore, the striped pattern in the captured image when the measurement object OB is captured by the light receiving device 12 also has a distorted shape. In addition, the reflectance at each location of the measurement object OB is often not constant, and the degree of shading at the darkest and lightest locations in the captured image is not constant. Therefore, in the captured image of the stripe pattern, the waveform of the light amount distribution along the direction perpendicular to the line direction of the stripe is a waveform deviated from the sine waveform, and the amplitude is not constant.

  Here, each pixel (for example, CCD or CMOS) constituting the light receiving device always receives light reflected at substantially the same location of the measurement object OB. That is, each pixel has a one-to-one correspondence with each measurement point of the measurement object OB. Therefore, if the original light distribution of the striped light has a sinusoidal waveform as shown in FIG. 9B, the striped pattern formed on the measurement object OB is moved (the stripe phase is shifted). In this case, the amount of reflected light received at each pixel (each light receiving position) also changes to a sine wave having the same frequency as the light amount distribution of the striped light. That is, when the fringe phase is shifted, the light amount curve of light received by each pixel has a sine waveform. However, the phase (initial phase) at the start point of the light amount curve of light received from each location in the stripe pattern is different. For example, considering points A, B, C, and D in the stripe pattern as shown in FIG. 9A, when the stripe phase changes, the reflected light from each point A, B, C, and D is reflected. The light amount change of the light amount curve in the light receiving pixel changes to a sine wave shape as shown in FIGS. 10A, 10B, 10C, and 10D, respectively, but the phase at the start point of the light amount curve ( The initial phases are different.

  Therefore, the phase value of the sine waveform of the luminance distribution in the striped pattern before movement (before shifting the phase), that is, the initial phase of the light amount curve is determined for each minute region (pixel) of the light receiver. In other words, the phase difference between the light amount curve and the reference sine waveform is determined. By making this phase value correspond to the stripe phase of the stripe pattern actually formed on the measurement object OB, it is possible to know from which stripe line of the irradiated stripe pattern the reflected light is received. In this case, since the phase value changes between 0 and 2π, there are a plurality of pixels and fringe phases having the same phase value. Therefore, the phase value of each pixel and the stripe line do not correspond one to one. In order to make a one-to-one correspondence, for example, by creating a point or line in which the amount of light is significantly different from the surroundings in a striped pattern, or by irradiating a point or line with light separately from the striped pattern. A place to be a mark is provided in a specific point or line in the striped pattern by a method such as performing. Then, when a location designated as the mark is detected, the location and a specific pixel of the light receiver are associated with each other in advance, so that each pixel and a striped line are paired in order from the corresponding location. Corresponding to 1. In addition to the above example, as a method for detecting a corresponding point on a one-to-one basis, detection is performed by changing the amplitude of the sine waveform in the luminance distribution of the striped pattern with regularity or changing the frequency of the sine waveform with regularity. There is also a method. Further, as described above, each pixel always receives light reflected at the same location of the measurement object OB. This indicates that the light receiving direction of the received light is always constant in each pixel. Therefore, when light is received by each pixel, a position vector whose size is undetermined is uniquely determined for each pixel. Therefore, in each pixel, the direction of the received light (position vector of undefined size; in other words, a straight line) and which stripe line of the irradiated stripe pattern (light emission source and stripe line are formed). 3D coordinates (x, y, z) on the measurement object OB can be obtained from the intersection of the plane and the straight line. That is, if the phase value is calculated for each micro area (pixel) of the light receiver, that is, for each light receiving position, and this phase value is made to correspond to the fringe phase of the irradiated light (if it corresponds to one line in the stripe pattern) ), The three-dimensional coordinates (x, y, z) on the measurement object OB can be obtained by calculation.

As described above, in the three-dimensional shape measurement by the phase shift method, it is necessary to calculate a phase value for each minute region (pixel) of the light receiver. In this case, the fringe phase is changed by adding 0, π / 2, π, 3 / 2π to the initial phase, and the light amounts (intensities) I0, I1, I2, I3 of the reflected light in the respective phase states. A method is often used in which the phase value φ is detected by the following calculation.
φ = tan ⁻¹ ((I3-I1) / (I2-I0))
In addition, the fringe phase position for detecting the amount of reflected light is increased, and the amount of reflected light is subjected to Fourier transform (or discrete Fourier transform if the amount of light data is digital data) to determine the frequency for each frequency and formed on the measurement object. By obtaining the phase at a frequency that matches the frequency of the striped pattern to be obtained, it is possible to calculate an accurate phase value from which noise due to extra reflected light such as secondary reflection is removed.
JP 2003-254732 A

  However, since the three-dimensional shape measurement by the phase shift method irradiates light with a striped pattern formed on the entire measurement object, the intensity of the irradiation light is individually controlled according to the reflectance of the irradiated portion of the irradiation light. I can't. For this reason, when the measurement object has both high reflectance and small reflectance, the pixel that receives the reflected light from the location with the high reflectance receives the light received by the light receiver near the maximum value of the reflected light. Data may be saturated. In such a case, a normal sinusoidal light amount curve may not be obtained at the pixel position (light receiving position). Further, since the intensity of the received light is too small in the pixel that receives the reflected light from the portion having a low reflectance, there is a possibility that an accurate light amount curve cannot be obtained at the pixel position (light receiving position). As described above, in the three-dimensional shape measurement by the conventional phase shift method, the waveform shape of the light amount curve may not be an appropriate shape for obtaining the phase value depending on the reflectance of the measurement object. There is a problem that the calculation accuracy deteriorates. Since the shape of the measurement object is obtained based on the phase value, the measurement accuracy of the three-dimensional shape is also deteriorated when the calculation accuracy of the phase value is deteriorated.

  The present invention has been made in view of the above problems, and its purpose is to form a stripe pattern on the measurement object, move the stripe pattern to change the stripe phase, and reflect on the surface of the measurement object. When measuring the three-dimensional shape of the measurement object by receiving the reflected light, that is, when measuring the three-dimensional shape of the measurement object by the phase shift method, the accuracy of the measurement object varies depending on the location. An object of the present invention is to provide a three-dimensional shape measuring apparatus or a three-dimensional shape measuring method capable of well measuring the shape.

  In order to achieve the above object, the present invention is characterized by light irradiation means for irradiating a measurement object with irradiation light so as to form a striped pattern in which a bright part and a dark part are periodically repeated on the measurement object, and measurement Stripe scanning means for changing the fringe phase so that the fringe phase, which is the phase at each location of the striped pattern formed on the object, becomes a plurality of different phases, and each of the plurality of different phases of the fringe phase A light receiving device that receives the reflected light of the irradiation light applied to the measurement object and outputs a light receiving signal corresponding to the amount of the received reflected light, and a light receiving signal output by the light receiving device. A phase value of a light amount curve representing a change in the amount of light received by the light receiver is calculated for each light receiving position of reflected light in the light receiver, and three-dimensional shape data of the measurement object is created based on the calculated phase value. Data processing hand And when the fringe phase is each of the plurality of different phases, the irradiation light is irradiated so as to irradiate the measurement object with a predetermined plurality of different intensities. Intensity control means for controlling the intensity, and the data processing means, for each light receiving position of the reflected light in the light receiver, based on a phase value obtained from a light reception signal output from the light receiver In each case where the measurement object is irradiated with the evaluation light regarding the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data is created based on the received light signal with the predetermined plurality of different intensities The evaluation data calculation means for calculating the measurement data and the evaluation data calculation means for each of the cases where the measurement object is irradiated with the irradiation light at the predetermined plurality of different intensities. Evaluation in which the measurement accuracy of the three-dimensional shape data is improved when the three-dimensional shape data of the measurement object is created from the evaluation data using the phase value obtained from the received light signal used to calculate the evaluation data. Evaluation data extraction means for extracting data, and shape data creation means for creating three-dimensional shape data of the measurement object based on the phase value obtained from the received light signal used for calculation of the evaluation data extracted by the evaluation data extraction means It is to be provided with.

  According to the three-dimensional shape measuring apparatus according to the invention, the intensity of the irradiation light irradiated on the measurement object is predetermined for each of the cases where the stripe phases of the stripe pattern formed on the measurement object are a plurality of different phases. Of different strengths. In addition, the reflected light of the irradiated light is received by the light receiver every time the irradiated light is irradiated to the measurement object at the predetermined plurality of different intensities, and the light receiver receives a light reception signal corresponding to the amount of the received reflected light. Output. Based on the received light signal, the evaluation data on the measurement accuracy when the three-dimensional shape of the measurement object is measured based on the phase value obtained from the received light signal is irradiated with the irradiation light at the predetermined plural different intensities. Calculated for each case. Evaluation data that improves the measurement accuracy of the three-dimensional shape data of the measurement object is extracted from the calculated evaluation data. Based on the phase value obtained from the received light signal used to calculate the evaluation data extracted in this way, three-dimensional shape data of the measurement object is created.

  Thus, the three-dimensional shape measuring apparatus of the present invention irradiates the measurement object with a plurality of intensities and forms a striped pattern on the measurement object for each light of each intensity. For this reason, the same location of the measurement object is irradiated with a plurality of irradiation lights having different intensities, and the reflected light when the irradiation lights of each intensity are irradiated is received by the light receiver and output from the light receiver. From each received light signal, evaluation data relating to the measurement accuracy of the three-dimensional shape data of the measurement object is obtained for each case where irradiation light with a plurality of intensities is irradiated. Therefore, evaluating the evaluation data calculated for each of the cases where the irradiation light of the plurality of intensities is irradiated, and extracting evaluation data from which the measurement accuracy of the three-dimensional shape data of the measurement object becomes good Therefore, it is most suitable for the reflectance at the irradiation position of the irradiated light from among the received light signals of the reflected light (or the phase value obtained from each received light signal) when the irradiation light of each intensity is irradiated. It is possible to select a light reception signal (or a phase value obtained from the light reception signal) of the reflected light received when the irradiation light having a high intensity is irradiated. Therefore, by measuring the three-dimensional shape of the measurement object using the phase value (or the selected phase value) calculated from the selected received light signal, the measurement of the three-dimensional shape data due to the change in the reflectance of the measurement object. The deterioration of accuracy can be prevented or suppressed.

  For example, the light irradiation means irradiates the measurement object with light in which the bright part and the dark part are periodically repeated, thereby forming a striped pattern in which the bright part and the dark part are periodically repeated on the measurement object. It is good to be. The light can be generated by, for example, entering laser light emitted from a laser light source into parallel light into a liquid crystal filter with a stripe pattern and projecting the transmitted light onto a measurement object. it can. Alternatively, the light can also be generated by dividing laser light emitted from a laser light source into parallel light into two laser lights and causing the two laser lights to interfere with each other in a phase-shifted state.

  The phase (stripe phase) at each location of the striped pattern is a direction perpendicular to the line direction of the striped pattern formed on the measurement object (the direction in which the brightness is continuously constant in the striped pattern). It is a phase in each part of the curve which shows the light quantity when the light quantity is detected along. This curve is generally a sinusoid. Further, the fringe scanning means may be changed so that the phase (stripe phase) at each portion of the striped pattern takes a plurality of different phases in one cycle. For example, when the fringe scanning means expresses one period of the fringe pattern as 2π, the initial phase is 0, π / 4, π / 2, 3π / 4, π, 5π / 4, 3 / 2π, 7π / 4, What can be changed into the striped pattern of the phase state which added 2 (pi) is good. Regarding the method of changing the phase, for example, when a striped pattern is formed by a liquid crystal filter, the striped phase of the striped pattern on the object to be measured is changed by changing the striped phase of the striped pattern drawn on the liquid crystal filter. A method of changing the above can be adopted.

  The light receiver receives the reflected light of the irradiation light applied to the measurement object, and outputs a light reception signal corresponding to the amount of the received reflected light. The light receiver is an area sensor in which a plurality of pixels (light receiving elements) are arranged in a predetermined region, and each pixel may output a light reception signal corresponding to the amount of reflected light received. Further, the light reception signal output from the light receiver may be amplified or discretized when used when obtaining a phase value or evaluation data.

  The intensity control means emits irradiation light so that irradiation light with a predetermined plurality of intensities can be emitted for each of the cases where the fringe phase of the stripe pattern formed on the measurement object is changed to a plurality of different phases by the fringe scanning means. It controls the intensity of the. For example, when the fringe phase changes to the initial phase added with 0, π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, 2π, In the case of (2), for example, the measurement object is irradiated with irradiation light having a large intensity, a medium intensity, and a small intensity. Although the predetermined number of different intensities is arbitrary, each value of the different intensities may be common between different fringe phases. For example, when the intensity levels of irradiation light are represented by levels 0, 1, 2 (level 0 <level 1 <level 2), three types of levels 0, 1, and 2 are obtained for each of the different fringe phases. It is preferable that the intensity of the irradiation light is controlled by the intensity control means so that the measurement object is irradiated with the intensity light.

  As a method for controlling the intensity of irradiation light, for example, when a laser light source is used as the light irradiation means, a method of controlling the intensity of irradiation light by changing the current and voltage supplied to the laser light source can be adopted. .

  The evaluation data calculation means calculates evaluation data for each case where the measurement object is irradiated with irradiation light at the predetermined plurality of different intensities. For example, when the intensity of irradiation light is changed to three levels 0, 1, and 2 as in the above example, evaluation data when the intensity is level 0, evaluation data when the intensity is level 1, and level 2 Evaluation data is calculated for each case.

  For example, the evaluation data extracting unit calculates the evaluation data when the intensity of the irradiation light is level 0, the evaluation data when it is level 1, and the evaluation data when it is level 2 as in the above example. Is used to extract evaluation data calculated based on the received light signal that improves the measurement accuracy of the three-dimensional shape data. Such extraction is performed by evaluating each evaluation data by comparing the evaluation data calculated for each irradiation light of each intensity with a predetermined value or relatively comparing them. The shape data creation means creates three-dimensional shape data of the measurement object based on the phase value obtained from the received light signal that is the basis of calculation of the evaluation data extracted by the evaluation data extraction means. In this case, the shape data creation means detects the fringe line in the striped pattern corresponding to the phase value obtained as described above, and determines the detected fringe line and the light receiving position in the light receiver that calculated the phase value. It may be used to calculate the three-dimensional coordinate value of the measurement object.

  The phase value is obtained based on a light reception signal output from the light receiver. Specifically, this phase value is received by the photoreceiver every time the fringe pattern of the striped pattern formed on the measurement object is changed to a plurality of different phases at each light receiving position (each pixel) of the photoreceiver. This is the initial phase of the light amount curve representing the change in the amount of reflected light, which can be said to be the phase difference between the light amount curve and the reference curve. The light amount curve is generally a sine wave.

  In the above invention, the data processing means measures the irradiation light at the predetermined plurality of different intensities based on the light reception signal output from the light receiver for each light reception position of the reflected light in the light receiver. A phase value calculating means for calculating a phase value for each case of irradiating an object, and a phase calculated by the phase value calculating means based on a received light signal used for calculating evaluation data extracted by the evaluation data extracting means Phase value selecting means for selecting a value, and the shape data creating means preferably creates three-dimensional shape data of the measurement object based on the phase value selected by the phase value selecting means. According to this, the phase value is calculated together with the evaluation data for each case where the measurement object is irradiated with the irradiation light at a predetermined plurality of different intensities. Then, the three-dimensional shape data of the measurement object is created using the phase value calculated based on the received light signal that is the basis for calculating the evaluation data extracted by the evaluation data extracting means.

  In the above invention, the data processing means is based on a received light signal selecting means for selecting a received light signal used for calculation of evaluation data extracted by the evaluation data extracting means, and a received light signal selected by the received light signal selecting means. Selected phase value calculating means for calculating the phase value, and the shape data creating means creates the three-dimensional shape data of the measurement object based on the phase value calculated by the selected phase value calculating means. There may be. According to this, the phase value corresponding to all the evaluation data is not calculated, and only the phase value corresponding to the extracted evaluation data is calculated. Then, the three-dimensional shape data of the measurement object is created using the calculated phase value.

In addition, another feature of the present invention is that a light irradiation means for irradiating the measurement object with irradiation light so as to form a stripe pattern in which the bright part and the dark part are periodically repeated on the measurement object, and the measurement object When the fringe scanning means changes the fringe phase so that the fringe phase, which is the phase at each location of the stripe pattern to be formed, becomes a plurality of different phases, and the fringe phase is each of the different phases A light receiver that receives reflected light of the irradiation light irradiated on the measurement object and outputs a light reception signal corresponding to the amount of the received reflected light, and the light receiver based on the light reception signal output by the light receiver Data processing for calculating a phase value of a light amount curve representing a light amount change of light received by the light receiving position for each reflected light in the light receiver, and generating three-dimensional shape data of the measurement object based on the calculated phase value Means In the three-dimensional shape measuring apparatus, the light receiver receives reflected light at a plurality of different light receiving times when the fringe phase is the plurality of different phases, and according to the amount of the received reflected light. A light reception signal is output for each case of receiving reflected light at the predetermined plurality of different light receiving times, and the data processing means is configured to output the light receiver for each light receiving position of the reflected light in the light receiver. Evaluation data relating to the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created based on the phase value obtained from the received light reception signal is calculated based on the predetermined plurality of different values based on the light reception signal. Evaluation data calculating means for calculating each case where the light receiver receives reflected light at a light receiving time;
The evaluation data calculating means obtains from the received light signal used for calculating the evaluation data from the evaluation data calculated for each case where the light receiver receives the reflected light at the predetermined different light receiving times. When the 3D shape data of the measurement object is created using the phase value obtained, the evaluation data extracting means for extracting the evaluation data that improves the measurement accuracy of the 3D shape data, and the evaluation data extracting means It is provided with shape data creating means for creating three-dimensional shape data of an object to be measured based on a phase value obtained from a received light signal for calculating evaluation data.

  According to the three-dimensional shape measuring apparatus according to the invention, when the light receiver receives the reflected light of the irradiation light irradiated on the measurement object, the stripe phase of the stripe pattern formed on the measurement object has a plurality of stripe phases. For each of the different phases, the reflected light is received at a plurality of predetermined different light receiving times, and the received light signal according to the amount of the received reflected light is received at the predetermined different light receiving times. Output for each case. Based on this received light signal, the evaluation data regarding the measurement accuracy when the three-dimensional shape of the measurement object is measured based on the phase value obtained from the received light signal is reflected by the light receiver at the predetermined different light receiving times. Is calculated for each case of receiving light. Evaluation data that improves the measurement accuracy of the three-dimensional shape data of the measurement object is extracted from the calculated evaluation data. Based on the phase value obtained from the received light signal used to calculate the evaluation data extracted in this way, three-dimensional shape data of the measurement object is created.

  As described above, in the three-dimensional shape measuring apparatus according to the present invention, when the fringe phase of the stripe pattern formed on the measurement object is each phase, the light receiver receives the reflected light at a plurality of different light receiving times. . The light receiving time represents the light receiving sensitivity when the light receiver receives the reflected light. Therefore, the light receiver receives the reflected light with a plurality of different light receiving sensitivities at the same location of the measurement object. Then, evaluation data relating to the measurement accuracy of the three-dimensional shape data of the measurement object is obtained from the light reception signal of the reflected light received at each light reception sensitivity. Therefore, the evaluation data calculated for each of the cases where the reflected light is received at the plurality of different light receiving times are evaluated, and the evaluation data that improves the measurement accuracy of the three-dimensional shape data of the measurement object is extracted from the evaluation data. Thus, the irradiation position of the irradiated light from the received light signals of the reflected light (or the phase value obtained from each received light signal) for each case where the reflected light is received during the plurality of light receiving times. It is possible to select a light reception signal (or a phase value obtained from the light reception signal) when the reflected light is received with the light reception sensitivity most suitable for the reflectivity at. Therefore, by creating the three-dimensional shape data of the measurement object using the phase value (or the selected phase value) calculated from the selected light reception signal, the three-dimensional shape data based on the change in the reflectance of the measurement object is obtained. Deterioration of measurement accuracy can be prevented or suppressed.

  The light receiving time is a time during which the light receiver receives reflected light. The light receiver preferably stores a physical quantity corresponding to the light energy of the reflected light received during the light receiving time and outputs a signal having an intensity corresponding to the stored physical quantity. As such a light receiver, a light receiver using a light receiving element such as a CCD or a CMOS can be employed. In this case, the light reception time is a time during which these elements receive reflected light, more specifically, a time during which charges are accumulated in these elements (charge accumulation time). The light receiving time can be set when a control device including a microcomputer such as a CPU, ROM, RAM outputs a command to the light receiver. In addition, the light receiver receives the reflected light in a predetermined plurality of light receiving times for each of the cases where the fringe pattern formed on the measurement object has a plurality of different phases by the fringe scanning unit. For example, when the fringe phase changes to the initial phase added with 0, π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, 2π, In this case, for example, the reflected light is received in three light receiving times each having a long, medium, and short light receiving time. The number of the predetermined different light receiving times is arbitrary, but the length of each of the different light receiving times may be common between different fringe phases. For example, when the light reception time is represented by A, B, and C (A <B <C), the light receiver reflects the reflected light in three light reception times of A, B, and C when the fringe phases are different from each other. It is recommended to receive light.

  The evaluation data calculation means calculates evaluation data for each case where the light receiver receives reflected light at the predetermined plurality of different light receiving times. For example, when the light receiver receives reflected light at three types of light receiving times A, B, and C as in the above example, the evaluation data obtained from the light receiving signal when the reflected light is received at the light receiving time A Then, evaluation data obtained from the light reception signal when the reflected light is received at the light reception time B and evaluation data obtained from the light reception signal when the reflected light is received at the light reception time C are calculated.

  The evaluation data extraction means is obtained from, for example, evaluation data obtained from the light reception signal when the reflected light is received at the light reception time A as in the above example, and from the light reception signal when the reflected light is received at the light reception time B. When the evaluation data obtained from the received light signal when the reflected light is received at the received light time C is calculated, based on the received light signal from which the measurement accuracy of the three-dimensional shape data becomes good. The calculated evaluation data is extracted. Such extraction is performed by evaluating each evaluation data by comparing the evaluation data calculated for each light receiving time with a predetermined value or relatively comparing them. The shape data creation means creates three-dimensional shape data of the measurement object based on the phase value obtained from the received light signal that is the basis of calculation of the evaluation data extracted by the evaluation data extraction means. In this case, the shape data creation means detects the fringe line in the striped pattern corresponding to the phase value obtained as described above, and determines the detected fringe line and the light receiving position in the light receiver that calculated the phase value. It may be used to calculate the three-dimensional coordinate value of the measurement object.

  In the above invention, the data processing means is configured to receive the light receiver at the predetermined plurality of different light reception times based on a light reception signal output from the light receiver for each light reception position of the reflected light in the light receiver. Phase value calculating means for calculating a phase value for each case of receiving reflected light, and a phase calculated by the phase value calculating means based on a received light signal used for calculating evaluation data extracted by the evaluation data extracting means Phase value selecting means for selecting a value is provided, and the shape data creating means creates three-dimensional shape data of the measurement object based on the phase value selected by the phase value selecting means. According to this, the phase value is calculated together with the evaluation data for each case of receiving the reflected light at a predetermined plurality of different light receiving times. Then, the three-dimensional shape data of the measurement object is created using the phase value calculated based on the received light signal from which the evaluation data extracted by the evaluation data extracting means is calculated.

  In the above invention, the data processing means is based on a received light signal selecting means for selecting a received light signal used for calculation of evaluation data extracted by the evaluation data extracting means, and a received light signal selected by the received light signal selecting means. Selected phase value calculating means for calculating the phase value, and the shape data creating means creates the three-dimensional shape data of the measurement object based on the phase value calculated by the selected phase value calculating means. There should be. According to this, the phase value corresponding to all the evaluation data is not calculated, and only the phase value corresponding to the extracted evaluation data is calculated. Then, the three-dimensional shape data of the measurement object is calculated using the calculated phase value.

  The evaluation data in the present invention is the case where the three-dimensional shape data of the measurement object is created using the received light signal corresponding to the evaluation data, that is, the phase value obtained from the received light signal from which the evaluation data is calculated. In addition, it is data related to the measurement accuracy of the three-dimensional shape data. Therefore, the quality of the measurement accuracy of the three-dimensional shape data is determined by the quality of the evaluation data. Here, since the three-dimensional shape data is obtained using the phase value, the measurement accuracy of the three-dimensional shape data depends on the accuracy of the phase value. Therefore, it can be said that this evaluation data determines whether the accuracy of the phase value is good or bad. The evaluation data may be calculated based on the received light signal received for each of the stripe patterns formed on the measurement object having a plurality of different phases. Further, since the phase value is the phase value of the light amount curve of the light received by the light receiver, the evaluation value may be obtained from this light amount curve and related to the shape of the light amount curve. In this case, the evaluation data may include data corresponding to the maximum value of the light amount curve and / or data corresponding to a deviation amount between the light amount curve and a sine curve equal to the frequency of the light amount curve. Measurement accuracy can be evaluated more accurately by setting the evaluation data to such local maximum values and deviation amounts. Further, the data corresponding to the deviation amount may be a ratio of the frequency indicating the frequency of the striped pattern to the total frequency in the frequency distribution obtained by Fourier transforming the light amount curve. According to this, the shift amount can be obtained more accurately. Further, when the light amount curve is obtained as digital data, the ratio of the frequency indicating the frequency of the striped pattern or the frequency range to the total frequency in the frequency distribution obtained by subjecting the obtained digital data to discrete Fourier transform as the deviation amount. Good.

  In addition, another feature of the present invention is that a light irradiation step for irradiating the measurement target with irradiation light so as to form a stripe pattern in which the bright part and the dark part are periodically repeated on the measurement target, and the measurement target A fringe scanning step for changing the fringe phase so that the fringe phase, which is a phase at each location of the stripe pattern to be formed, becomes a plurality of different phases, and the fringe phase is each of the different phases In addition, when the intensity change step of changing the intensity of the irradiation light so that the irradiation light is irradiated to the measurement object at a predetermined plurality of different intensities, and when the fringe phase is each of the plurality of different phases, For each case where the measurement object is irradiated with the predetermined plurality of different intensities, the receiver receives the reflected light of the irradiation light, and receives the light reception signal corresponding to the amount of the received reflected light. Receiving step output by the detector The three-dimensional shape data when the three-dimensional shape data of the measurement object is created based on the phase value obtained from the light receiving signal output from the light receiving device in the light receiving step for each light receiving position of the reflected light in the light receiving device. An evaluation data calculation step for calculating evaluation data related to measurement accuracy of shape data for each case where irradiation light with a predetermined plurality of different intensities is irradiated on the measurement object based on the received light signal, and the evaluation data calculation It is calculated based on the received light signal used to calculate the evaluation data from the evaluation data calculated for each case where the measurement object is irradiated with the irradiation light with the predetermined plurality of different intensities in the step. Extracts evaluation data that improves the measurement accuracy of the 3D shape data when the 3D shape data of the measurement object is created using the phase value An evaluation data extraction step, and a shape data creation step for creating three-dimensional shape data of the measurement object based on the phase value obtained from the light reception signal for calculating the evaluation data extracted in the evaluation data extraction step. Including a three-dimensional shape measuring method. Also by this method, when measuring the three-dimensional shape of the measurement object by the phase shift method, the shape measurement can be accurately performed even if the reflectance of the measurement object varies greatly depending on the location.

  In this case, in the above method, for each light receiving position of the reflected light in the light receiver, irradiation light is measured with the predetermined plurality of different intensities based on a light receiving signal output from the light receiver in the light receiving step. In the phase value calculating step for calculating the phase value for each case where the object is irradiated, and in the phase value calculating step based on the received light signal used for calculating the evaluation data extracted in the evaluation data extracting step A phase value selecting step for selecting the calculated phase value, and the shape data creating step includes the three-dimensional shape data of the measurement object based on the phase value selected in the phase value selecting step. It is good to create. Alternatively, the method includes a light reception signal selection step for selecting a light reception signal used for calculation of the evaluation data extracted in the evaluation data extraction step, and a phase based on the light reception signal selected in the light reception signal selection step. A selection phase value calculation step for calculating a value, and the shape data creation step includes the three-dimensional shape data of the measurement object based on the phase value calculated in the selection phase value calculation step. It may be created.

  Still another feature of the present invention is that a light irradiation step of irradiating the measurement object with irradiation light so as to form a striped pattern in which the bright part and the dark part are periodically repeated on the measurement object, and the measurement object A fringe scanning step for changing the fringe phase so that the fringe phase, which is a phase at each location of the striped pattern, is formed in a plurality of different phases; and the fringe phase is each of the plurality of different phases. A light receiving step in which the light receiver receives the reflected light of the irradiation light at a predetermined plurality of different light receiving times, and the light receiver outputs a light reception signal corresponding to the amount of the received reflected light; Measurement of the three-dimensional shape data in the case where the three-dimensional shape data of the measurement object is created based on the phase value obtained from the light reception signal output from the light receiver in the light receiving step at each light receiving position of the reflected light. Evaluation data calculation step for calculating the evaluation data for the degree of light received at the predetermined plurality of different light reception times based on the light reception signal, and the predetermined plurality of different light receptions in the evaluation data calculation step An object to be measured using a phase value calculated based on a received light signal used for calculation of the evaluation data from evaluation data calculated for each case where the light receiver receives reflected light over time. An evaluation data extraction step for extracting evaluation data that improves the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data is created, and a light reception signal for calculating the evaluation data extracted in the evaluation data extraction step A three-dimensional shape including a shape data creating step of creating three-dimensional shape data of a measurement object based on a phase value obtained from It is to a constant method. Also by this method, when measuring the three-dimensional shape of the measurement object by the phase shift method, the shape measurement can be accurately performed even if the reflectance of the measurement object varies greatly depending on the location.

  In this case, the above-described method is configured such that, for each light reception position of the reflected light in the light receiver, the light receiver at the predetermined plurality of different light reception times based on a light reception signal output from the light receiver in the light reception step. A phase value calculating step for calculating a phase value for each case of receiving reflected light, and a phase value calculating step based on the received light signal used for calculating the evaluation data extracted in the evaluation data extracting step. A phase value selecting step for selecting the calculated phase value, and the shape data creating step creates three-dimensional shape data of the measurement object based on the phase value selected in the phase value selecting step. It should be a thing. Alternatively, the method includes a light reception signal selection step for selecting a light reception signal used for calculation of the evaluation data extracted in the evaluation data extraction step, and a phase based on the light reception signal selected in the light reception signal selection step. A selection phase value calculation step for calculating a value, and the shape data creation step creates three-dimensional shape data of the measurement object based on the phase value calculated in the selection phase value calculation step. It may be a thing.

(First embodiment)
The first embodiment of the present invention will be described below. FIG. 1 is an overall configuration diagram of a three-dimensional shape measuring apparatus using a phase shift method to which the present invention is applied. The three-dimensional shape measuring apparatus 1 includes a three-dimensional sensor 10, a data processing device 30, a controller 50, an input device 52, and a display device 54. The three-dimensional sensor 10 irradiates the measurement object OB with laser light, receives reflected light of the laser light irradiated on the measurement object OB, and outputs a light reception signal. The three-dimensional sensor 10 includes an irradiation device 11 that emits laser light, a light receiving device 12 that receives reflected light of the laser light irradiated on the measurement object OB, and a control that controls the laser light emitted from the irradiation device 11. A circuit 13.

  The irradiation device 11 includes a laser light source 112, a collimating lens 114, a liquid crystal filter 116, and an expansion lens 118. The laser light source 112 is composed of a semiconductor laser or the like, and emits laser light having an intensity corresponding to a supplied current or voltage. The collimating lens 114 is disposed at a position where the laser light emitted from the laser light source 112 is incident, and the incident laser light is converted into parallel light. The liquid crystal filter 116 is disposed at a position where the laser beam that has been collimated by the collimating lens 114 is incident, and displays a predetermined image by liquid crystal. The extension lens 118 is disposed at a position where the laser light that has passed through the liquid crystal filter 116 is incident, and the incident laser light is enlarged to irradiate the entire irradiation surface of the measurement object OB with the laser light. The liquid crystal filter 116 has a striped pattern in which striped lines are periodically repeated at regular intervals based on image data supplied from an image data supply circuit 132 described later. The irradiation device 11 irradiates the measurement object OB with the laser light emitted from the laser light source 112 through the liquid crystal filter 116 on which the above-described stripe pattern is drawn, and this irradiation illuminates the measurement object OB with a bright part and a dark part. Forms a stripe pattern A that is periodically repeated, and corresponds to the light irradiation means of the present invention.

  The light receiving device 12 includes a condenser lens 122 and a photosensor 124 as a light receiver of the present invention. The condensing lens 122 is disposed at a position where the reflected light of the laser light irradiated on the measurement object OB can be incident, and condenses the incident reflected light. The photosensor 124 receives the reflected light of the laser light irradiated on the measurement object OB through the condenser lens 122 and outputs a light reception signal corresponding to the received reflected light. In the present embodiment, the photosensor 124 is an area sensor in which pixels (light receiving elements) such as CCDs or CMOSs are arranged in a plane, and each pixel outputs a signal (light reception signal) corresponding to the amount of reflected light.

  The control circuit 13 includes an image data supply circuit 132, a laser drive circuit 134, and a laser intensity control circuit 136. The image data supply circuit 132 supplies image data to the liquid crystal filter 116 based on a command signal from the controller 50 described later. The image data supply circuit 132 stores image data in a memory in the circuit. When an instruction is received from the controller 50, the image data supply circuit 132 supplies image data, which is transmittance data, to each liquid crystal constituting the liquid crystal filter 116. By this supply, the liquid crystal filter 116 forms a stripe pattern. The stripe pattern formed on the liquid crystal filter 116 has a luminance distribution in a direction perpendicular to the line direction of the stripe as a sine curve. The memory of the image data supply circuit 132 stores image data having a reference luminance distribution (reference image data) and a plurality of image data whose phases are shifted from the reference image data. In response to this command, the image data shifted by the commanded phase from the reference image data is output. For this reason, the fringe pattern formed on the measurement object OB can change the fringe phase, which is the phase at each location of the fringe pattern, within one cycle in response to a phase command from the controller 50. In the present embodiment, the image data supply circuit 132 stores reference image data and eight image data whose phases are shifted by 1 / 4π with respect to the reference image data. Therefore, by changing the image data supplied from the image data supply circuit 132 to the liquid crystal filter 116, the stripe phase of the stripe pattern formed on the measurement object OB also changes. That is, the image data supply circuit 132 can change the stripe phase of the stripe pattern formed on the measurement object OB based on a command from the controller 50 so as to have a plurality of different phases. This corresponds to the fringe scanning means of the invention.

  The laser drive circuit 134 supplies current and voltage for emitting laser light to the laser light source 112 based on commands from the controller 50 and a laser intensity control circuit 136 described later. The laser intensity control circuit 136 corresponds to the intensity control means of the present invention. The laser intensity control circuit 136 receives a command signal related to the control of the intensity of the laser beam from the controller 50 and responds to the command signal with the intensity of the laser beam emitted from the laser light source 112. The laser drive circuit 134 controls the current and voltage output to the laser light source 112 so that the laser intensity becomes high. In response to an instruction from the laser intensity control circuit 136, laser beams having different intensities are emitted from the laser light source 112. Further, the laser intensity control circuit 136 changes the intensity of the laser beam based on a command from the controller 50, thereby irradiating a plurality of intensities with respect to one state of the fringe phase of the stripe pattern formed on the measurement object OB. The intensity of the laser light is controlled so as to irradiate each light. For this reason, when the stripe phase of the stripe pattern formed on the measurement object OB is a plurality of different phases, a stripe pattern is formed by a plurality of laser beams having different intensities. In the present embodiment, the laser intensity control circuit 136 sets the intensity level of the laser beam in three stages as will be described later.

  The data processing device 30 corresponds to the data processing means of the present invention, and includes a sensor signal extraction circuit 32, a data operation circuit 34, and a three-dimensional image generation device 36. The sensor signal extraction circuit 32 outputs a signal (light reception signal) corresponding to the amount of reflected light received by each pixel of the photosensor 124 by outputting a signal to the photosensor 124, and outputs the signal in this way. Input the signal. Then, the signal input from each pixel is amplified, and the signal intensity is converted into digital data (sensor data) and output to the data calculation circuit 34. The light receiving time in the photosensor 124, that is, the time interval (charge accumulation time) for outputting a signal to each pixel is appropriately set by the controller 50. In this embodiment, the charge accumulation time is constant.

  Based on a command from the controller 50, the data operation circuit 34 selects a pixel P (α, β) (α: x in the photosensor 124) in the photosensor 124 from the sensor data output from the sensor signal extraction circuit 32. The sensor data of the pixel number in the axial direction, β: the pixel number in the y-axis direction in the photosensor 124) is fetched and stored in the memory in the circuit. In addition, based on the command from the controller 50, the phase value φ, the maximum value H of the light amount curve, and the deviation amount E from the sine curve of the light amount curve are calculated for each pixel (light receiving position) from the stored sensor data. The image is output to the image generation device 36. Details of each value to be calculated will be described later.

  The three-dimensional image generation device 36 performs processing according to the program flowchart shown in FIG. 3 based on the value input from the data operation circuit 34, and provides an optimum phase value for each pixel P (α, β) of the photosensor 124. Select φ (α, β). Then, in the same manner as the three-dimensional shape measurement by the normal phase shift method, the stripe pattern of the irradiation light having the phase value corresponding to the selected phase value φ (α, β) is detected, and the three-dimensional image is preliminarily detected. The irradiation direction θx is obtained from a table indicating the relationship between the stripe line and the irradiation direction θx stored in the generation device 36, and the light receiving position (X (α), Y) of the pixel P (α, β) of the photosensor 124 is obtained. The three-dimensional coordinate value (x, y, z) of the laser beam irradiation part on the measurement object OB is calculated from the direction of the reflected light corresponding to (β)) and the irradiation direction θx. Further, three-dimensional image data of the measurement object OB is generated from the set (point group data) of the three-dimensional coordinate values (x, y, z) and output to the display device 54.

  The irradiation direction θx is a plane including a line of predetermined stripes (for example, stripes S in FIG. 1) formed on the measurement object OB and the focal point R of the laser light emitted from the irradiation device 11; This is an angle formed by the optical axis L of the laser beam emitted from the irradiation device 11 and converted into parallel light by the collimating lens 114. In addition, when the pixel P (α, β) and the striped stripe line are associated with each other based on the phase value, the phase value changes between 0 and 2π. Exists. For this reason, in the present embodiment, in the stripe pattern in which the luminance distribution is a sine waveform in the reference image data, the light amount at one place is significantly different from the surroundings (for example, one dark line in the bright part or one line in the dark part). The bright line) is provided, and this portion is made to correspond to the predetermined pixel P (α, β) on a one-to-one basis, and the stripe line and the pixel P (α, β) To make it correspond. There are several methods for detecting a reference point for making a one-to-one correspondence between the stripe line and the pixel P (α, β). For example, the light amount at one place in the stripe pattern is significantly different from the surroundings. The above-described method of detecting a specific point by providing a point may be used, or a method of detecting a specific point by irradiating a predetermined point or line separately from the light irradiation of the stripe pattern, or the luminance distribution of the stripe pattern Alternatively, the amplitude or frequency of the sine waveform may be changed to detect a specific point based on these changes.

  The display device 54 displays a 3D image generated from the 3D image data input from the 3D image generation device 36. The input device 52 performs several settings such as an input for starting the three-dimensional shape measurement, setting of the laser light intensity, and setting of the moving position (phase shift amount value) of the striped pattern when the data calculation circuit 34 takes in the data. .

  The controller 50 includes a microcomputer composed of a CPU, ROM, RAM, and the like as main components, and outputs command signals to various circuits and the three-dimensional image generation device 36 based on input instructions from the input device 52 to operate them. It functions as a control means for controlling.

  In the three-dimensional shape measuring apparatus 1 configured as described above, when an operator inputs a measurement start command from the input device 52, the controller 50 starts the measurement program shown in FIG. Hereinafter, description will be given according to this measurement program. In this embodiment, the stripe phase of the stripe pattern formed on the measurement object OB is changed by π / 4 and the laser intensity level is changed in three stages. May be.

  This measurement program is started in step S100 in the figure, and in step S102, the phase counter n and the intensity counter m are initialized (n = 0, m = 0). In step S104, various circuits are activated. Next, in step S106, a command is output to the image data supply circuit 132 so as to output an image pattern whose phase is shifted by n · (π / 4) from the reference image. When step S106 is first passed, the phase counter n is set to 0, so that the image data supply circuit 132 outputs an image pattern with a phase shift of 0, that is, a reference image. As a result, a stripe pattern of the reference image is displayed on the liquid crystal filter 116.

  Subsequently, the controller 50 proceeds to step S108, sets the intensity level of the laser beam to level m, and outputs the set value to the laser intensity control circuit 136. Here, in the present embodiment, the intensity level of the laser beam is made up of three levels of level 0, level 1 and level 2, where level 0 is the smallest intensity, level 2 is the largest intensity, and level 1 is the level. It is an intermediate intensity between 0 and level 2. The laser intensity control circuit 136 controls the current and voltage that the laser driving circuit 134 supplies to the laser light source 112 so that the laser light has an intensity corresponding to the intensity level specified by the controller 50.

  By executing the processes from steps S102 to S108, the laser light source 112 emits laser light having an intensity level of level m. The laser light emitted from the laser light source 112 is collimated by the collimating lens 114, enters the liquid crystal filter 116, and irradiates the measurement object OB through the expansion lens 118. The liquid crystal filter 116 has an image pattern in which the phase is shifted by n · (π / 4) from the reference image. As described above, this image pattern is a striped pattern, and the luminance is sinusoidal along a direction perpendicular to the line direction of the stripe. Therefore, the striped pattern drawn on the liquid crystal filter 116 is projected onto the measurement object OB, and a striped pattern in which the bright part and the dark part are periodically repeated is formed on the entire measurement object OB (light irradiation step). The reflected light of the irradiation light that forms the stripe pattern is received by the photosensor 124. Each pixel P (α, β) constituting the photosensor 124 receives reflected light at each light receiving position, and outputs a received light signal corresponding to the amount of the received reflected light to the sensor extraction circuit 32.

  Next, the controller 50 waits for the elapse of a predetermined time T set as a time longer than the charge accumulation time of the photosensor 124 in step S109, and then proceeds to step S110. The controller 50 sends the sensor data D (n, m) Instruct to capture. As a result, the data calculation circuit 34 takes in the sensor data D (n, m) from the sensor signal take-out circuit 32. The sensor data D (n, m) is obtained when the photosensor 124 receives the reflected light of the laser beam irradiated to the measurement object OB when the phase counter is n and the intensity counter is m. This is data obtained by amplifying the light reception signal output from each pixel P (α, β) by the sensor signal extraction circuit 32 and converting the signal intensity into digital data. Therefore, it can be said that the sensor data input from the sensor signal extraction circuit 32 to the data calculation circuit 34 is a light reception signal output from each pixel P (α, β) of the photosensor 124, and each pixel (α, β) received light. Think of it as light intensity data. In this case, as described above, the photosensor 124 is an area sensor, and a plurality of pixels are arranged in the vertical direction (x direction) and the horizontal direction (y direction), and each pixel P (α, β) is Each photosensor 124 has coordinate values (X (α), Y (β)) indicating light receiving positions. In this step S110, the data calculation circuit 34 converts the light reception signal data (light reception data) in each pixel P (α, β) into coordinate values (X (α), Y (β)) that are the light reception positions of the pixels. Import in association with.

  Thereafter, the controller 50 proceeds to step S112, and determines whether the intensity counter m is 3 or more. When passing through this step for the first time, the intensity counter m is 0, so the determination in this step is “No” and the process proceeds to step S114. In step S114, the intensity counter m is incremented. Then, the process returns to step S108. In this manner, as steps S108 to S114 are repeatedly executed, the intensity counter m is incremented to 0, 1, and 2 in step S114. As a result, while the phase state of the laser light applied to the measurement object OB is a predetermined state (phase state shifted by n · (π / 4) from the reference image), the measurement object OB has a low intensity. (M = 0: level 0), medium (m = 1: level 1), and large (m = 2: level 2) are irradiated with the respective laser beams, and the measurement object OB is irradiated with the laser beams having the respective intensities. A striped pattern is formed on (strength changing step). In step S110, the data calculation circuit 34 takes in the sensor data D (n, m) every time a striped pattern is formed on the measurement object OB by the laser beams having the respective intensities. If the determination in step S112 is “Yes”, the process proceeds to step S116.

In step S116, it is determined whether the phase counter n is 9 or more. Since the phase counter n is 0 when first passing through this step, the determination in this step is “No” and the process proceeds to step S118. In step S118, the phase counter n is incremented, and in the subsequent step S120, the intensity counter m is initialized (m = 0). Then, the process returns to step S106. By repeatedly executing steps S106 to S120, the phase counter n is sequentially incremented in step S118, so that the fringe phase of the image pattern output from the image data supply circuit 132 to the liquid crystal filter 116 repeats steps S106 to S120. Are sequentially shifted by π / 4. For this reason, the measurement object OB has stripe patterns of 0, π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π that are initially formed. Nine shifted stripe patterns are sequentially formed (stripe scanning step). Further, while the striped pattern formed on the measurement object OB takes the respective phase states, the laser light intensity level sequentially changes to level 0, level 1 and level 2 by repeating steps S108 to S114. Therefore, when the phase shift amount of the fringe phase of the striped pattern formed on the measurement object OB is each of the plurality of different phases, the photosensor 124 reflects the irradiation light irradiated with three types of intensities. Are received for each of the fringe phase states (light receiving step). In step S110, the data calculation circuit 34 obtains sensor data (light reception data) obtained from the light reception signal output from the photosensor 124 for each state of the fringe phase via the sensor extraction circuit 32, and for each state. Each light receiving position (each pixel) is acquired every time irradiation light is irradiated with intensity. Therefore, the sensor data D (n, m) shown in Table 1 is taken into the data calculation circuit 34.
In Table 1, α _m represents the last number of the X coordinate of the pixel position, and β _m represents the last number of the Y coordinate of the pixel position. As can be seen from Table 1, the data calculation circuit 34 acquires sensor data when the fringe phase is in each state for each pixel P (α, β) of the photosensor 124 for each of three levels of intensity.

  When it is determined in step S116 that the phase counter n is 9 or more, the process proceeds to step S122. The fact that the phase counter n is 9 or more means that the sensor data in the phase counter n (n = 0 to 8) less than that, that is, the phase of the striped pattern is 0, π / 4, π / 2, 3π / 4, π , 5π / 4, 3π / 2, 7π / 4, and 2π, the sensor data capture is completed. Therefore, in this case, the operation of various circuits is stopped in step S122 to stop the laser light irradiation, and the process proceeds to step S124, and the phase value φ (α, β, m is sent to the data arithmetic circuit 34 in step S124. ), The maximum value H (α, β, m) of the light amount curve, and the deviation amount E (α, β, m) from the sine curve of the light amount curve are calculated. The phase value φ (α, β, m) may be calculated by applying the sensor data D (0, m) to D (8, m) to the calculation formula described in the prior art. Then, a method of calculating by a Fourier transform capable of obtaining a phase value by removing noise is used.

  That is, a curve connecting sensor data D (0, m) to D (8, m) corresponding to the pixel P (α, β) for which the phase value φ (α, β, m) is to be obtained has a sine waveform. It becomes a close periodic curve. Therefore, when the corresponding sensor data D (0, m) to D (8, m) is subjected to discrete Fourier transform to create a frequency distribution diagram divided for each predetermined frequency range, fringes formed on the measurement object OB. The frequency distribution has a peak in the frequency range near the pattern frequency. Powers outside the frequency range near the stripe pattern frequency can be regarded as noise. The value constituting the frequency in the frequency range in the vicinity of the frequency of the striped pattern is subjected to inverse Fourier transform, and the phase at the start point of the sine curve represented thereby (the phase shift from the reference sine curve) is represented by the pixel P (α, It is assumed that the phase value φ (α, β, m) at β). In this way, the data calculation circuit 34 calculates the phase value φ (α, β, m) for each light receiving position (X (α), Y (β)) of the corresponding pixel P (α, β). And it calculates | requires for every intensity | strength (namely, every intensity counter m) of the irradiated laser beam (phase value calculation step).

  The maximum value H (α, β, m) of the light amount curve is the maximum value of the curve connecting the sensor data D (0, m) to D (8, m) in the pixel P (α, β). The maximum value of the sensor data D (0, m) to D (8, m) may be simply used, or a light amount curve may be estimated by approximating a sine curve from these data, and the maximum value may be obtained. The deviation amount E (α, β, m) of the light amount curve from the sine curve is obtained by Fourier transforming the sensor data D (0, m) to D (8, m) in the pixel P (α, β) in this embodiment. This is the ratio of the frequency in the frequency range in the vicinity of the fringe pattern frequency to the total frequency when a frequency distribution diagram divided into predetermined frequency ranges is created. In this case, the frequency distribution diagram used when calculating the phase value can be used. Note that the ratio of frequencies other than frequencies in the frequency range near the frequency of the striped pattern with respect to the overall frequencies may be used as the shift amount E (α, βm). In addition, a sinusoidal curve having the same frequency as the striped pattern is obtained by the least square method based on the sensor data D (0, m) to D (8, m) without using Fourier transform, and the obtained sinusoidal curve and each sensor data D are obtained. The sum of squares of the distances from (0, m) to D (8, m) may be used as the deviation amount E (α, β, m). These local maximum values H (α, β, m) and deviation amounts E (α, β, m) are also received by the respective pixels P (α, β) in the same manner as the phase values φ (α, β, m). It is determined for each position (X (α), Y (β)) and for each laser beam intensity (that is, for each intensity counter m) (evaluation data calculation step).

In this way, the data calculation circuit 34 corresponds to the sensor data D (n, m) corresponding to all the pixels P (α, β) to which the sensor data D (0, m) to D (8, m) are input. ), The phase value φ (α, β, m), the maximum value H (α, β, m) of the light amount curve, and the deviation amount E (α of the light amount curve from the sine curve) for each intensity level of the laser light. , Β, m). These calculation data are sent from the data operation circuit 34 to the three-dimensional image generation device 36. Therefore, the values shown in Table 2 are input to the three-dimensional image generation device 36.
As shown in Table 2, for each pixel P (α, β), the phase value φ (α, β, m), the maximum value H (α, β) for each intensity level of the laser light irradiated on the measurement object OB. , M), and three data groups consisting of the deviation E (α, β, m). In each pixel, the data group shown in the upper part of the data partitioned by the dotted line in the table is the data group calculated when the intensity level of the laser beam is low (level 0), and the data group shown in the middle part is the laser. The data group calculated when the light intensity level is medium (level 1), and the data group shown in the lower part are data groups calculated when the laser light intensity level is high (level 2).

  Of the values shown in Table 2, the pixel position X (α), the pixel position Y (β), and the phase value φ (α, β, m) are used when calculating the three-dimensional shape of the measurement object OB. It is a value and corresponds to the data for shape calculation.

  When the phase value φ (α, β, m) is a value in which the value of the sensor data D (n, m) from which the phase value φ (α, β, m) is calculated coincides with a sine curve representing the phase value to be originally obtained. When the three-dimensional shape data of the measurement object OB is created using the calculated phase value, the measurement accuracy of the three-dimensional shape data is good. On the other hand, when the value of the sensor data D (n, m), which is the basis for calculating the phase value φ (α, β, m), is a value greatly deviated from the sine curve representing the phase value to be originally obtained, When the three-dimensional shape data of the measurement object OB is created using the calculated phase value, the measurement accuracy of the three-dimensional shape data is poor. Therefore, the measurement accuracy of the three-dimensional shape data of the measurement object OB depends on the value of the sensor data D (n, m), and thus the maximum value H (α, β, m) and the deviation E (α, β, m). ) Can be an index representing how much the sensor data D (n, m) is different from a sinusoidal curve representing a phase value to be originally obtained. For example, if the maximum value H (α, β, m) is too large, the sensor data D (n, m) may reach the upper limit value. In this case, the sensor data D (n, m) The value of may not be able to indicate the original sinusoidal value. Further, when the deviation amount E (α, β, m) is too small (that is, when the deviation is large), there is a possibility that the value of the sensor data D (n, m) is greatly deviated from the value on the original sine curve. There is. Thus, the maximum value H (α, β, m) and the deviation amount E (α, β, m) are determined from the sine curve representing the phase value that the sensor data D (n, m) should originally obtain. In other words, it can be said that the evaluation data represents the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data of the measurement object OB is created using the phase value.

  After the phase value and the evaluation data are calculated in step S124 and the calculation result is input to the three-dimensional image generation device 36, the controller 50 proceeds to step S126. 3 is executed to select the optimum phase value from the three phase values obtained for each pixel, and the three-dimensional shape of the measurement object OB is calculated using the selected phase value. .

  The three-dimensional shape data calculation program shown in FIG. 3 evaluates evaluation data obtained for each intensity of laser light in each pixel P (α, β) of the photosensor 124, and in the data group to which the evaluation data belongs. Evaluation data that improves the measurement accuracy when three-dimensional shape data of the measurement object OB is created using the shape calculation data, and the shape calculation data (phase value and light receiving position) of the data group to which the extracted evaluation data belongs. ), And the three-dimensional shape data of the measurement object OB is created using the selected shape calculation data. This program is started in step S200 in FIG. 3, and pixel coordinate numbers α and β are initialized (α = 0, β = 0) in step S202. In step S204, the local maximum values H (α, β, 0), H (α, β, 1), H (α, β, 2) as evaluation data obtained in the pixel P (α, β) are obtained. Take out and extract evaluation data whose value is not less than the lower limit A and not more than the upper limit B (evaluation data extraction step). The values A and B serving as the extraction reference are an upper limit value and a lower limit value that can accurately specify the maximum value of the light amount curve. By executing the processing in this step, a light amount curve such as the light amount curve shown in FIG. 4A that is too large for the sensor data D (n, m) to indicate the maximum value, Like the light amount curve shown in 4 (b), the maximum value obtained from the light amount curve in which the maximum value is too small to specify a clear maximum value is excluded. The light amount curve shown in FIG. 4A may be generated when, for example, reflected light is received when a laser beam having a high intensity is irradiated onto a portion where the reflectance of the measurement object is high. The light amount curve shown in FIG. 4B may be generated when, for example, reflected light is received when a low-intensity laser beam is irradiated onto a portion of the measurement object having a low reflectance.

  Here, there is a high possibility that the light amount curve shown in FIG. 4A and the light amount curve shown in FIG. 4B cannot show an accurate maximum value as described above. In such a case, there is a high possibility that the value of the sensor data D (n, m) is largely deviated from the value on the sine curve representing the phase value that should be originally obtained. Therefore, the accuracy of the phase value calculated using such sensor data D (n, m) is also poor, and as a result, the measurement accuracy of the three-dimensional shape data of the measurement object obtained from the phase value may be deteriorated. high. Therefore, in step S214, as described above, the data group including the evaluation data that is considered to be deteriorated in the measurement accuracy of the three-dimensional shape data of the measurement object is excluded, and the data group that is considered that the measurement accuracy is good is narrowed down. Will be.

  Next, the three-dimensional image generation apparatus 36 proceeds to step S206, and determines whether the number of evaluation data extracted in step S204 is one. If the determination in step S206 is Yes, that is, if the maximum value H extracted in step S204 is one, the process proceeds to step S210. On the other hand, if the determination in step S206 is No, the process proceeds to the next step S208.

  In step S208, deviations E (α, β, 0), E (α, β, 1), E (α, β, 2) are taken out as evaluation data obtained for each intensity of the laser beam. The largest one is selected (evaluation data extraction step). At this time, it is not necessary to extract the deviation amount E in step S208 from the data group to which the maximum value H not extracted in step S204 belongs. Further, in this case, the deviation amount E is a fringe with respect to the entire frequency when a frequency distribution diagram in which the sensor data D (0, m) to D (8, m) is Fourier-transformed and divided into predetermined frequency ranges is created. Since the frequency ratio is in the frequency range near the pattern frequency, the larger the deviation amount E, the closer the waveform of the curve represented by the sensor data D (0, m) to D (8, m) is closer to the sine waveform. When the deviation amount E is a ratio of frequencies other than the frequency range in the vicinity of the fringe pattern frequency to the total frequencies when the frequency distribution diagram is created by the Fourier transform, the smaller the deviation amount E, the more data In this case, in step S208, the one having the smallest deviation amount E is selected.

  The process of step S208 is a process of selecting a deviation amount calculated from a curve closest to the sine curve from the deviation amount E as evaluation data. In this process, for example, when the light amount curve shown in FIG. 5A and the light amount curve shown in FIG. 5B are obtained from the sensor data, both the curves are Fourier-transformed, respectively, and FIG. 6A and FIG. A frequency distribution chart as shown in FIG. 6B is created, and these frequency distribution charts are compared, and the frequency distribution in FIG. The process is the same as selecting a figure. The light amount curve represented by the deviation amount E thus selected has a shape closer to a sine waveform, and the phase value calculated from the curve having a waveform close to a sine waveform is the phase value to be originally obtained. Is predicted to be the same or close to that. Therefore, when the three-dimensional shape of the measurement object OB is measured based on such a phase value, the measurement accuracy is considered to be good. Note that this process is not a process of extracting the data corresponding to the predetermined range, but a process of comparing the evaluation data and selecting the most preferable value, so that there is always one evaluation data remaining by the process of step S208. Become.

  By executing the processes in steps S204 to S208, the three-dimensional image generation device 36 finally extracts one evaluation data (evaluation data extraction step). Then, in the next step S210, the three-dimensional image generation device 36 determines the phase value φ (α, β, m) in the data group to which the extracted evaluation data (maximum light amount evaluation data or deviation amount evaluation data) belongs. Is selected as the formal phase value φ (α, β) (phase value selection step). Next, in step S212, it is determined whether the coordinate number β of the Y coordinate value of the currently evaluated pixel P (α, β) is the last coordinate number βm. When this determination is No, a pixel P (α, β) that has not yet selected an optimum phase value φ (α, β) remains among pixels whose X coordinate value is X (α). It will be. Therefore, if the determination in step S212 is No, the process proceeds to step S214, β is incremented, and the process returns to step S204 to repeat the above extraction and selection. If the determination in step S212 is Yes, the optimum phase value φ (α, β) has been selected for all the pixels having the X coordinate value X (α). In this case, the process proceeds to step S216. .

  In step S216, it is determined whether or not the X coordinate number α of the currently evaluated pixel P (α, β) is the last coordinate number αm. When this determination is No, the pixel whose coordinate number α of the X coordinate value is α + 1 or more has not yet selected the optimum phase value φ (α, β). Accordingly, if the determination in step S216 is No, the process proceeds to step S218, α is incremented, β is initialized (β = 0) in step S220, and then the process returns to step S204 to repeat the above extraction and selection. . If the determination in step S216 is Yes, it can be considered that the extraction and selection has been completed for all pixels, and in this case, the process proceeds to step S222.

  In step S222, the irradiation direction θx (α, β) of the stripe line in the striped pattern corresponding to the selected phase value φ (α, β) is detected by calculation performed in the three-dimensional shape measurement by the phase shift method. Is done. Here, the phase value φ is repeated with a value of 0 to 2π, and the fringe phase is also repeated with a phase value of 0 to 2π. Therefore, in order to make the phase value φ (α, β) and the stripe phase of the striped pattern have a one-to-one correspondence with each light receiving position (X (α), Y (β)) of each pixel P (α, β), As described above, a line having a light amount significantly different from the surroundings is provided at one place in the stripe pattern in which the luminance distribution has a sine waveform in the reference image data, and a pair of a pixel and a stripe line is set based on this place. The pixel and the stripe line are associated with each other by the phase value in this order.

  After calculating the irradiation direction θx (α, β) of the stripe line in step S222, the three-dimensional image generation device 36 proceeds to step S224, and the position of the pixel P (α, β) (X (α), Y (Β)) (these values are values representing the direction of the reflected light) and the irradiation direction θx (α, β) of the corresponding fringe line, and the corresponding three-dimensional coordinate values ( x, y, z) is calculated. Then, the process proceeds to step S226 to finish the execution of this program.

  In this way, after the controller 50 causes the three-dimensional image generation device 36 to calculate the three-dimensional coordinate value (point cloud data) of the measurement object OB in step S126 of FIG. 2, the controller 50 proceeds to step S128. The 3D image generation device 36 generates 3D image data of the measurement object OB using the 3D coordinate values (point cloud data) (shape data generation step), and outputs the generated 3D image data to the display device 54. To do. As a result, a three-dimensional image of the measurement object OB is displayed on the display device 54 based on the input three-dimensional image data.

  As described above, the three-dimensional shape measuring apparatus 1 of the present embodiment is configured so that the irradiation light has a plurality of different intensities when the stripe phase of the stripe pattern formed on the measurement object OB is each of a plurality of different phases. Is provided with a laser intensity control circuit 136 as an intensity control means for controlling the intensity of the irradiated light so that the measurement object OB is irradiated. Further, the data processing device 30 irradiates the measurement object with the irradiation light with a predetermined plurality of different intensities based on the light reception signal (sensor data D (n, m)) output from the photosensor 124. In this case, the phase value φ (α, β, m) is calculated for each light receiving position (X (α), Y (β)), and the measured object is calculated using the calculated phase value φ (α, β, m). When the three-dimensional shape data of OB is created, the maximum value H (α, β, m) and the shift amount (α, β, m) as evaluation data relating to the measurement accuracy of the three-dimensional shape data are obtained as the received light signal (sensor Based on the data D (n, m)), the data calculation circuit 34 for calculating each of the cases where the measurement object OB is irradiated with the irradiation light with a plurality of predetermined different intensities, and the data calculation circuit 34 Measure the irradiated light at multiple different intensities From the evaluation data (maximum value H (α, β, m), deviation E (α, β, m)) calculated for each case where the object OB is irradiated, the corresponding phase value φ ( α, β, m), that is, the three-dimensional measurement object OB using the phase value φ (α, β, m) obtained from the received light signal (sensor data D (n, m)) used to calculate the evaluation data. Extracting evaluation data that improves the measurement accuracy of the three-dimensional shape data when the shape data is created, and a phase value obtained from the received light signal (sensor data D (n, m)) obtained by calculating the extracted evaluation data and a three-dimensional image generation device 36 that generates three-dimensional shape data of the measurement object OB based on φ (α, β).

  Therefore, by evaluating the maximum value H (α, β, m) and the shift amount E (α, β, m) as evaluation data, the phase value φ (α, β calculated for the irradiation light of each intensity is obtained. M), the phase value calculated when the irradiation light having the intensity most suitable for the reflectance at the irradiation position of the irradiation light, that is, the phase at which the measurement accuracy of the three-dimensional shape measurement is the best. The value φ (α, β) can be selected. By measuring the three-dimensional shape of the measurement object OB using the phase value φ (α, β) thus selected, the measurement accuracy of the three-dimensional shape data is prevented from deteriorating due to the change in the reflectance of the measurement object. Alternatively, it can be suppressed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the said 1st Embodiment, while changing the intensity | strength of the laser beam irradiated to a measuring object, for every intensity | strength based on evaluation data while calculating | requiring a phase value in each point of a light receiving element for every intensity | strength of the changed laser beam An example is shown in which the optimum phase value is selected from the calculated phase values. On the other hand, in this embodiment, the intensity of the laser beam applied to the measurement object is constant, the photosensor light reception times are set to a plurality of different light reception times, and the reflected light received at each of the different light reception times is received. A phase value and evaluation data are obtained from the data, and an optimum phase value is selected from the phase values obtained for each light receiving time based on the evaluation data. Hereinafter, the above feature points will be mainly described.

  The basic configuration of the three-dimensional shape measuring apparatus of this embodiment is the same as that of the three-dimensional shape measuring apparatus 1 shown in FIG. 1 described in the first embodiment. Therefore, the present embodiment also uses the configuration of the three-dimensional shape measuring apparatus 1 shown in FIG. 1 and the above description. However, the laser intensity control circuit 136 controls the current and voltage that the laser driving circuit 134 supplies to the laser light source 112 so that the laser light source 112 always emits laser light with a constant intensity. This is different from the first embodiment. The laser intensity control circuit 136 may be omitted, and a constant intensity command may be output from the controller 50 side to the laser drive circuit 122.

  Further, when measuring the three-dimensional shape of the measurement object OB using the three-dimensional shape measurement apparatus of the present embodiment, the controller 50 executes the shape measurement program shown in FIG. This program is started in step S300 of FIG. 7, and the phase counter n and the time counter m are initialized (n = 0, m = 0) in step S302. Next, various circuits are operated in step S304. Subsequently, in step S <b> 306, the controller 50 outputs a command to the image data supply circuit 132 so that the image data having a phase of n · (π / 4) is drawn on the liquid crystal filter 116. As a result, the laser light emitted from the laser light source 112 passes through the liquid crystal filter 116 and becomes striped light. The striped light is irradiated onto the measurement object OB, and a stripe pattern A is formed on the measurement object OB (light irradiation step). The reflected light of the irradiation light that forms the stripe pattern A is received by the photosensor 124.

  Next, the controller 50 sets the charge accumulation time τ to time τm in step S308. Here, the charge accumulation time is the light reception time when the CCD or CMOS, which is each light receiving element constituting the photosensor 124, receives reflected light, and each light receiving element accumulates charge by receiving the reflected light. It is time to do. This charge accumulation time is set by the controller 50. Specifically, the controller 50 stores three types of time τ0, τ1, and τ2 as the charge accumulation time, and sets the charge accumulation time set by the value of the time counter m (m = 0, 1, 2). Distribute. Now, since the time counter m is initialized in step S302, the charge accumulation time τm is initially set to τ0.

  When the charge accumulation time τm is set in step S308, the controller 50 instructs the photosensor 124 via the sensor signal extraction circuit 32 to receive the reflected light at the charge accumulation time τm. As a result, a light receiving element such as a CCD in the photosensor 124 receives the reflected light for the set charge accumulation time τm and outputs a light receiving signal.

  Next, in step S309, the process waits for the elapse of a predetermined time T (T> τ0, τ1, τ2), and then proceeds to step S310. In this step S310, the sensor data D (n, m) is taken into the data calculation circuit 34. To As a result, the data calculation circuit 34 takes in the sensor data D (n, m) from the photosensor 124. The sensor data D (n, m) is obtained when the photosensor 124 receives the reflected light of the laser beam irradiated to the measurement object OB when the phase counter is n and the time counter is m, and the charge accumulation time τm. This is data obtained by amplifying the light reception signal output from each pixel P (α, β) of the photosensor 124 by the sensor signal extraction circuit 32 and digitalizing the signal intensity, and corresponds to the light reception signal output from each pixel of the photosensor 124. .

  Next, the controller 50 proceeds to step S312, determines whether the time counter m is 3 or more, and proceeds to step S314 if the determination result is No. In step S314, the time counter m is incremented. Thereafter, the process returns to step S307. When the fringe phase of the fringe pattern formed on the measurement object OB is n · (π / 4) by repeating these steps S307 to S314, the photosensor 124 has three types of charge accumulation times (τ0, τ1, The reflected light is received at τ 2), and sensor data D (n, m) is taken into the data calculation circuit 34 for each charge accumulation time.

  If it is determined in step S312 that the time counter m is 3 or more, the process proceeds to step S316. In step S316, it is determined whether the phase counter n is 9 or more. If the determination result is No, the process proceeds to step S318, and the phase counter n is incremented. In step S320, the time counter m is initialized (m = 0), and the process returns to step S306. By repeating these steps S306 to S320, the phase counter n is sequentially incremented, and the fringe phase of the fringe pattern formed on the measurement object OB is sequentially changed (stripe scanning step). Each time the fringe phase changes, the reflected light of the irradiation light forming the fringe pattern is received in three types of charge accumulation times (τ0, τ1, τ2) (light receiving step), and the corresponding sensor data is data. Obtained by the arithmetic circuit 34. For this reason, the data calculation circuit 34 receives the same data as in Table 1 above.

  When it is determined in step S316 that the phase counter n is 9 or more, the process proceeds to step S322. In step S322, the operation of various circuits is stopped. Next, the controller 50 proceeds to step S324, and causes the data calculation circuit 34 to calculate a phase value and evaluation data (phase value calculation step, evaluation data calculation step). Since this calculation is the same as the calculation in step S124 described in the first embodiment, a specific description is omitted. However, in this embodiment as well, one light receiving position (pixel) is the same as in the first embodiment. For each, a plurality of phase values are calculated together with the evaluation data under conditions where parameters affecting the intensity of the received light signal are different (in this embodiment, different charge accumulation times).

  Next, the controller 50 proceeds to step S326 and causes the three-dimensional image generation device 36 to calculate the three-dimensional shape data of the measurement object OB. Since this calculation is the same as the calculation in step S126 described in the first embodiment, a detailed description thereof will be omitted. However, in this embodiment as well, as in the first embodiment, one light receiving position (pixel) is obtained. Each of the plurality of evaluation data (maximum values H (α, β, m), deviation amount E () calculated under conditions where the parameters affecting the intensity of the received light signal are different (in this embodiment, different charge accumulation times). When the three-dimensional shape data of the measurement object OB is created using the phase value φ (α, β, m) obtained from the sensor data used for calculating the evaluation data among α, β, m)) The evaluation data that improves the measurement accuracy of is extracted (evaluation data extraction step), and the phase value obtained from the sensor data calculated from the extracted evaluation data is used as the formal phase value φ (α, β) at the light receiving position Select (Phase Selection step), to create three-dimensional coordinate values of the measurement object OB (point group data) by using the phase value selected (shape data creation step). In performing the extraction, selection, and calculation, the program of FIG. 3 described in the first embodiment can be used.

  Subsequently, the controller 50 proceeds to step S328 and causes the three-dimensional image generation device 36 to create three-dimensional image data of the measurement object OB using the three-dimensional coordinate values (point cloud data) (shape data creation step). The display unit 54 is instructed to output the three-dimensional image data. As a result, a three-dimensional image of the measurement object OB is displayed on the display device 54 based on the input three-dimensional image data.

  As described above, in the three-dimensional shape measuring apparatus according to the present embodiment, the photosensor 124 has a predetermined plurality of stripes in each case where the stripe phases of the stripe pattern formed on the measurement object OB are a plurality of different phases. Each time the reflected light is received at different charge accumulation times (light receiving times) τ0, τ1, τ2, and a received light signal corresponding to the amount of the received reflected light is received at a plurality of predetermined different charge accumulation times. Output. In addition, the data processing device 30 reflects the reflected light at a plurality of predetermined different charge accumulation times τ 0, τ 1, τ 2 based on the light reception signal (sensor data D (n, m)) output from the photo sensor 124. The phase value φ (α, β, m) in each case received by 124 is calculated, and the three-dimensional shape data when the three-dimensional shape data of the measurement object OB is created using the calculated phase value. The maximum value H (α, β, m) and the shift amount E (α, β, m) as evaluation data relating to the measurement accuracy of a predetermined plurality of values are determined based on the received light signal (sensor data D (n, m)). The data calculation circuit 34 calculates for each case when the reflected light is received at different charge accumulation times, and the photosensor 124 receives the reflected light at a plurality of predetermined different charge accumulation times by the data calculation circuit 34. Measured using the phase value φ (α, β, m) obtained from the received light signal (sensor data D (n, m)) used to calculate the evaluation data from the evaluation data calculated for each light. When the three-dimensional shape data of the object OB is created, evaluation data that improves the measurement accuracy of the three-dimensional shape data is extracted, and the phase value φ (α, β) used for calculating the extracted evaluation data is extracted. And a three-dimensional image generation device 36 for generating three-dimensional shape data of the measurement object OB based on the three-dimensional image data.

  Therefore, by calculating the maximum value H (α, β, m) and the shift amount E (α, β, m) as evaluation data, calculation is performed for each case where reflected light is received in a plurality of charge accumulation times. Among the measured phase values φ (α, β, m), the phase value calculated when the reflected light is received in the charge accumulation time most suitable for the reflectance at the irradiation position of the irradiated light, that is, three-dimensional The phase value φ (α, β) that provides the best measurement accuracy of the shape measurement can be selected. By measuring the three-dimensional shape of the measurement object OB using the phase value φ (α, β) thus selected, the measurement accuracy of the three-dimensional shape data is prevented from deteriorating due to the change in the reflectance of the measurement object. Alternatively, it can be suppressed.

  The present invention can be variously modified. For example, in the above embodiment, the data calculation circuit 34 calculates the phase value φ together with the maximum value H and the shift amount E as evaluation data, and outputs the phase value φ to the 3D image generation device 36. The phase value φ that provides the best measurement accuracy of the three-dimensional shape measurement is selected by evaluating the evaluation data. Instead, the data calculation circuit 34 calculates only the maximum value H and the deviation E as the evaluation data. Then, the sensor data D (light reception signal) that is output to the three-dimensional image generation device 36 together with the sensor data D, and that the measurement accuracy of the three-dimensional shape measurement becomes the best by extracting the evaluation data by the three-dimensional image generation device 36. And the phase value φ may be calculated from the selected sensor data D. Also by this, the same effect as the above embodiment can be obtained. In this case, the three-dimensional image generation device 36 corresponds to a light reception signal selection unit that selects a light reception signal (sensor data) from which the extracted evaluation data is calculated, and a phase value based on the selected light reception signal (sensor data). This corresponds to selection phase value calculation means for calculating. Moreover, in the said embodiment, although the intensity | strength of the laser beam irradiated or the light reception time of reflected light is changed in the state which made the striped pattern of the striped pattern formed in a measuring object constant, irradiation is performed contrary to this. Repeatedly shifting the stripe phase of the striped pattern by one period of the striped pattern with the intensity of the laser beam to be received or the light receiving time of the reflected light being constant, and in each repetition, the intensity of the laser beam or the light receiving time of the reflected light It may be changed.

It is a whole block diagram of the three-dimensional shape measuring apparatus by the phase shift method to which this invention is applied. 5 is a flowchart of a measurement program executed by a controller in the three-dimensional shape measurement apparatus according to the first embodiment. 3 is a flowchart of a three-dimensional shape data calculation program executed by the three-dimensional image generation device in the three-dimensional shape measurement apparatus according to the first embodiment. It is a figure which shows the waveform pattern of the light quantity curve which cannot specify a clear maximum value, (a) is a light quantity curve which cannot specify local maximum value because light quantity is too large, (b) is too small light quantity. The light quantity curve which cannot specify local maximum is shown. It is a figure which shows the example of the light quantity curve obtained from sensor data. FIG. 6 is a frequency distribution diagram created by Fourier transforming the light amount curve of FIG. 5. It is a flowchart of the measurement program which a controller performs in the three-dimensional shape measuring apparatus which concerns on 2nd Embodiment. It is the schematic of the three-dimensional shape measuring apparatus which measures the three-dimensional shape of a measuring object using the conventional phase shift method. (A) is a figure showing the stripe pattern formed in a liquid crystal or a slide in a phase shift method, (b) is light intensity along the direction orthogonal to the line direction of the stripe pattern shown in (a). FIG. 9A is a curve showing a change in light quantity at each point when the fringe phase is shifted in FIG. 9A, and FIGS. 9A, 9B, 9C, and 9D are points in FIG. 9A, respectively. The light quantity curves in A, B, C, and D are shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Three-dimensional shape measuring apparatus, 10 ... Three-dimensional sensor, 11 ... Irradiation device (light irradiation means), 112 ... Laser light source, 114 ... Collimating lens, 116 ... Liquid crystal filter, 12 ... Light receiving device, 124 ... Photosensor (Receiver), 13 ... control circuit, 132 ... image data supply circuit (stripe scanning means), 134 ... laser drive circuit, 136 ... laser intensity control circuit (intensity control means), 30 ... data processing device (data processing means) 32 ... sensor signal extraction circuit, 34 ... data operation circuit (evaluation data calculation means, phase value calculation means), 36 ... three-dimensional image generation device (evaluation data extraction means, shape data creation means, phase value selection means), 50 ... Controller (control means), E ... Deviation amount, H ... Maximum value, τ ... Charge accumulation time, φ ... Phase value, D (n, m) ... Sensor data (light reception signal)

Claims (13)

Light irradiation means for irradiating the measurement object with irradiation light so as to form a stripe pattern in which the bright part and the dark part are periodically repeated on the measurement object, and the respective portions of the stripe pattern formed on the measurement object A fringe scanning means for changing the fringe phase so that the fringe phase which is a phase in the plurality of different phases, and irradiation light irradiated on the measurement object when the fringe phase is each of the plurality of different phases And a light receiver that outputs a light reception signal corresponding to the amount of the reflected light received, and a light amount change of the light received by the light receiver based on the light reception signal output by the light receiver. A three-dimensional shape measuring apparatus comprising: a data processing unit that calculates a phase value of a light amount curve for each light receiving position of reflected light in the light receiver and creates three-dimensional shape data of a measurement object based on the calculated phase value. In
When the fringe phase is each of the plurality of different phases, comprising intensity control means for controlling the intensity of the irradiation light so that the irradiation light is irradiated to the measurement object with a predetermined plurality of different intensity,
The data processing means includes
Measurement of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created based on the phase value obtained from the light reception signal output from the light receiver for each light receiving position of the reflected light in the light receiver. Evaluation data calculating means for calculating evaluation data on accuracy for each case where the measurement object is irradiated with irradiation light at the predetermined plurality of different intensities based on the received light signal;
Obtained from the received light signal used to calculate the evaluation data from the evaluation data calculated for each case where the evaluation data calculation means irradiates the measurement object with the irradiation light at the predetermined plurality of different intensities. Evaluation data extracting means for extracting evaluation data that improves the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created using the phase value;
Shape data creating means for creating three-dimensional shape data of a measurement object based on a phase value obtained from a received light signal used for calculation of evaluation data extracted by the evaluation data extracting means, Three-dimensional shape measuring device. The three-dimensional shape measuring apparatus according to claim 1,
The data processing means includes
A phase value for each case where the measurement object is irradiated with the irradiation light at the predetermined plurality of different intensities based on the light reception signal output from the light receiver for each light reception position of the reflected light in the light receiver. Phase value calculating means for calculating
Phase value selection means for selecting the phase value calculated by the phase value calculation means based on the received light signal used to calculate the evaluation data extracted by the evaluation data extraction means,
The three-dimensional shape measuring apparatus, wherein the shape data creating means creates three-dimensional shape data of a measurement object based on the phase value selected by the phase value selecting means. Light irradiation means for irradiating the measurement object with irradiation light so as to form a stripe pattern in which the bright part and the dark part are periodically repeated on the measurement object, and the respective portions of the stripe pattern formed on the measurement object A fringe scanning means for changing the fringe phase so that the fringe phase which is a phase in the plurality of different phases, and irradiation light irradiated on the measurement object when the fringe phase is each of the plurality of different phases And a light receiver that outputs a light reception signal corresponding to the amount of the reflected light received, and a light amount change of the light received by the light receiver based on the light reception signal output by the light receiver. A three-dimensional shape measuring apparatus comprising: a data processing unit that calculates a phase value of a light amount curve for each light receiving position of reflected light in the light receiver and creates three-dimensional shape data of a measurement object based on the calculated phase value. In
The light receiver receives reflected light at a plurality of predetermined different light receiving times when the fringe phase is the plurality of different phases, and receives a light reception signal corresponding to the amount of the received reflected light. Output for each case of receiving reflected light at different light receiving times,
The data processing means includes
Measurement of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created based on the phase value obtained from the light reception signal output from the light receiver for each light receiving position of the reflected light in the light receiver. Evaluation data calculation means for calculating evaluation data on accuracy for each case where the light receiver receives reflected light at the predetermined plurality of different light receiving times based on the light receiving signal;
The evaluation data calculating means obtains from the received light signal used for calculating the evaluation data from the evaluation data calculated for each case where the light receiver receives the reflected light at the predetermined different light receiving times. Evaluation data extraction means for extracting evaluation data that improves the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created using the phase value obtained;
Shape data creating means for creating three-dimensional shape data of a measurement object based on a phase value obtained from a received light signal used for calculation of evaluation data extracted by the evaluation data extracting means, Three-dimensional shape measuring device. The three-dimensional shape measuring apparatus according to claim 3,
The data processing means includes
A phase value for each case where the light receiver receives the reflected light at the predetermined plurality of different light reception times based on a light reception signal output from the light receiver for each light reception position of the reflected light in the light receiver. Phase value calculating means for calculating
Phase value selection means for selecting the phase value calculated by the phase value calculation means based on the received light signal used to calculate the evaluation data extracted by the evaluation data extraction means,
The three-dimensional shape measuring apparatus, wherein the shape data creating means creates three-dimensional shape data of a measurement object based on the phase value selected by the phase value selecting means. In the three-dimensional shape measuring apparatus according to claim 1 or 3,
The data processing means includes
A light reception signal selection means for selecting a light reception signal used for calculation of the evaluation data extracted by the evaluation data extraction means;
A selected phase value calculating means for calculating a phase value based on the received light signal selected by the received light signal selecting means,
The three-dimensional shape measuring apparatus, wherein the shape data creating means creates three-dimensional shape data of a measurement object based on the phase value calculated by the selected phase value calculating means. In the three-dimensional shape measuring apparatus according to any one of claims 1 to 5,
The three-dimensional shape measuring apparatus, wherein the evaluation data includes data corresponding to a maximum value of the light amount curve. The three-dimensional shape measuring apparatus according to any one of claims 1 to 6,
The evaluation data includes data corresponding to a deviation amount between the light amount curve and a sine curve equal to a frequency of the light amount curve. The three-dimensional shape measuring apparatus according to claim 7,
The data corresponding to the deviation amount is a ratio of the frequency indicating the frequency of the stripe pattern to the total frequency in the frequency distribution obtained by Fourier transforming the light amount curve, and a three-dimensional shape measuring apparatus . A light irradiation step of irradiating the measurement object with irradiation light so as to form a stripe pattern in which the bright part and the dark part are periodically repeated on the measurement object;
A fringe scanning step for changing the fringe phase so that the fringe phase, which is the phase at each location of the striped pattern formed on the measurement object, becomes a plurality of different phases;
When the fringe phase is each of the plurality of different phases, an intensity changing step of changing the intensity of the irradiation light so that the irradiation object is irradiated to the measurement object with a predetermined plurality of different intensities;
When the fringe phase is the plurality of different phases, the receiver receives the reflected light of the irradiation light in each case where the measurement object is irradiated with the predetermined plurality of different intensities. A light receiving step in which the light receiver outputs a light reception signal corresponding to the amount of reflected light received;
The three-dimensional shape when the three-dimensional shape data of the measurement object is created based on the phase value obtained from the light reception signal output from the light receiver in the light receiving step for each light receiving position of the reflected light in the light receiver. An evaluation data calculation step for calculating evaluation data related to measurement accuracy of data for each case where irradiation light of the predetermined plurality of different intensities is irradiated on the measurement object based on the light reception signal;
Based on the received light signal used to calculate the evaluation data from the evaluation data calculated for each case where the measurement object is irradiated with the irradiation light at the predetermined plurality of different intensities in the evaluation data calculation step. An evaluation data extraction step for extracting evaluation data that improves the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created using the phase value calculated
A shape data creation step for creating three-dimensional shape data of the measurement object based on a phase value obtained from the received light signal used for calculation of the evaluation data extracted in the evaluation data extraction step;
A three-dimensional shape measuring method. The three-dimensional shape measuring method according to claim 9,
For each light receiving position of the reflected light in the light receiver, each of the measurement objects is irradiated with irradiation light with the predetermined plurality of different intensities based on a light reception signal output from the light receiver in the light receiving step. A phase value calculating step for calculating a phase value in the case of
A phase value selection step of selecting the phase value calculated in the phase value calculation step based on the received light signal used for calculation of the evaluation data extracted in the evaluation data extraction step;
The shape data creation step creates 3D shape data of a measurement object based on the phase value selected in the phase value selection step. A light irradiation step of irradiating the measurement object with irradiation light so as to form a stripe pattern in which the bright part and the dark part are periodically repeated on the measurement object;
A fringe scanning step for changing the fringe phase so that the fringe phase, which is the phase at each location of the striped pattern formed on the measurement object, becomes a plurality of different phases;
When the fringe phase is each of the plurality of different phases, the light receiver receives the reflected light of the irradiation light at a predetermined plurality of different light receiving times, and receives the received light signal according to the amount of the received reflected light. A light receiving step output from the receiver;
The three-dimensional shape when the three-dimensional shape data of the measurement object is created based on the phase value obtained from the light reception signal output from the light receiver in the light receiving step for each light receiving position of the reflected light in the light receiver. Evaluation data calculation step for calculating evaluation data related to measurement accuracy of data for each case of receiving light at the predetermined plurality of different light receiving times based on the light receiving signal;
The light reception signal used for calculating the evaluation data from the evaluation data calculated for each case where the light receiver receives the reflected light at the predetermined plurality of different light reception times in the evaluation data calculation step. An evaluation data extraction step for extracting evaluation data that improves the measurement accuracy of the three-dimensional shape data when the three-dimensional shape data of the measurement object is created using the phase value calculated based on
A shape data creation step for creating three-dimensional shape data of the measurement object based on a phase value obtained from the received light signal used for calculation of the evaluation data extracted in the evaluation data extraction step;
A three-dimensional shape measuring method. The three-dimensional shape measuring apparatus according to claim 11,
For each of the light receiving positions of the reflected light in the light receiver, each of the light receivers receives the reflected light at the predetermined plurality of different light receiving times based on a light receiving signal output by the light receiver in the light receiving step. A phase value calculating step for calculating a phase value in the case of
A phase value selection step of selecting the phase value calculated in the phase value calculation step based on the received light signal used for calculation of the evaluation data extracted in the evaluation data extraction step;
The shape data creation step creates 3D shape data of a measurement object based on the phase value selected in the phase value selection step. The three-dimensional shape measuring apparatus according to claim 9 or 11,
A light reception signal selection step for selecting a light reception signal used for calculation of the evaluation data extracted in the evaluation data extraction step;
A selection phase value calculation step of calculating a phase value based on the light reception signal selected in the light reception signal selection step, and
The shape data creating step creates 3D shape data of a measurement object based on the phase value calculated in the selected phase value calculating step.