JP2016109461A - Calibration system, reflection member, and inspection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calibration system that is related to an inspection system using a time correlation camera and calibrates the position and attitude to control a surface to be inspected.SOLUTION: A calibration system for an inspection system of an embodiment comprises: a reflection member including a reflection surface that has a plurality of shape discontinuity parts generating phase discontinuities provided in a time-correlation image; an interval detection part that detects an interval between the phase discontinuities in a time-series image obtained by photographing the reflection surface, and a parameter calculation part that calculates a parameter corresponding to at least one of the position and attitude of a surface to be inspected during inspection on the basis of the detected interval.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a calibration system, a reflective member, and an inspection system.

  Conventionally, there has been proposed a technique for irradiating an object to be inspected, imaging reflected light from the surface of the object to be inspected as image data, and detecting an abnormality of the object to be inspected based on a change in luminance of the image data. Has been.

  In this case, a technique has been proposed in which the intensity of light applied to the object to be inspected is periodically changed and an abnormality is detected based on a change in luminance of the captured image data.

JP 2014-2125 A

  However, in the prior art, the light intensity is changed, but the imaged image data does not include information on time transition when the light intensity is changed. For this reason, when detecting an abnormality of the object to be inspected with the captured image data, the detection accuracy may be lowered.

  Further, when an inspection of a product or the like as an object to be inspected is performed, it is desirable that the position and orientation of the inspection target surface be set with higher accuracy or more efficiency, for example.

  The calibration system according to the embodiment includes a planar illumination unit that provides periodic temporal change and spatial change of light intensity, and a time correlation image that generates a time correlation image by a time correlation camera or an imaging system that performs an equivalent operation. From the generation unit and the time correlation image, a feature corresponding to the distribution of the normal vector on the surface to be inspected, and a feature for detecting an abnormality by at least one of a difference from the surroundings and a difference from the reference surface is calculated. A reflection system having a reflection surface provided with a plurality of shape discontinuities that cause phase discontinuities in a time-correlated image, In the time correlation image obtained by imaging the reflection surface, an interval detection unit that detects an interval between discontinuous portions of the phase, and the position and appearance of the inspection target surface at the time of inspection based on the detected interval And a parameter calculating section that calculates a parameter corresponding to at least one of.

FIG. 1 is a diagram illustrating a configuration example of an inspection system including a calibration system according to the first embodiment. FIG. 2 is a block diagram showing the configuration of the time correlation camera of the first embodiment. FIG. 3 is a conceptual diagram showing frames accumulated in time series in the time correlation camera of the first embodiment. FIG. 4 is a diagram illustrating an example of a fringe pattern irradiated by the illumination device of the first embodiment. FIG. 5 is a diagram illustrating a first detection example of abnormality of an object to be inspected by the time correlation camera according to the first embodiment. FIG. 6 is a diagram showing an example of the amplitude of light that changes in accordance with the abnormality when the abnormality shown in FIG. FIG. 7 is a diagram illustrating a second example of detection of abnormality of the inspected object by the time correlation camera according to the first embodiment. FIG. 8 is a diagram illustrating a third example of detection of abnormality of an object to be inspected by the time correlation camera of the first embodiment. FIG. 9 is a diagram illustrating an example of a fringe pattern output from the illumination control unit according to the first embodiment to the illumination device. FIG. 10 is a diagram illustrating an example of a wave shape representing a stripe pattern after passing through the screen of the first embodiment. FIG. 11 is a flowchart illustrating a procedure of abnormality detection processing based on amplitude in the abnormality detection processing unit of the first embodiment. FIG. 12 is a flowchart illustrating a procedure of an abnormality detection process based on a phase in the abnormality detection processing unit of the first embodiment. FIG. 13 is a flowchart illustrating a procedure of abnormality detection processing based on amplitude and intensity in the abnormality detection processing unit of the first embodiment. FIG. 14 is a flowchart illustrating a procedure of an inspection process for an object to be inspected in the inspection system of the first embodiment. FIG. 15 is a diagram illustrating a switching example of a fringe pattern output from the illumination control unit according to the second modification. FIG. 16 is a diagram illustrating an example in which the illumination control unit of Modification 2 irradiates the surface including the abnormality (defect) with a stripe pattern. FIG. 17 is a diagram showing the relationship between the abnormality (defect) and the stripe pattern on the screen when the stripe pattern is changed in the y direction. FIG. 18 is a diagram illustrating an example of a fringe pattern output from the illumination control unit of Modification 3 to the illumination device. FIG. 19 is an exemplary schematic diagram of an arrangement of the screen, the reflecting member, and the time correlation camera when the calibration using the reflecting member is performed by the calibration system of the embodiment. FIG. 20 is a schematic plan view of an example of a reflecting member used in calibration. FIG. 21 is a schematic side view of an example of a reflecting member used in calibration. FIG. 22 is an enlarged exemplary schematic diagram of the reflecting member when the calibration using the reflecting member is performed by the calibration system of the embodiment. FIG. 23 is a flowchart illustrating an example of a calibration procedure using a reflecting member by the calibration system of the embodiment. FIG. 24 is a schematic plan view of a first modification of the reflecting member used in calibration. FIG. 25 is a schematic side view of a first modification of the reflecting member used in calibration. FIG. 26 is a schematic plan view of a second modification of the reflecting member used in calibration. FIG. 27 is a schematic plan view of a third modification of the reflecting member used in calibration. FIG. 28 is a schematic side view of a third modification of the reflecting member used in calibration.

<Basic configuration of time correlation camera>
The inspection system of this embodiment will be described. The inspection system of the first embodiment has various configurations for inspecting an object to be inspected. FIG. 1 is a diagram illustrating a configuration example of an inspection system according to the present embodiment. As shown in FIG. 1, the inspection system of the present embodiment includes a PC 100, a time correlation camera 110, a lighting device 120, a screen 130, and a moving mechanism 140.

  The moving mechanism 140 is used to fix the inspection object 150 and changes the position and orientation of the surface of the inspection object 150 that can be imaged by the time correlation camera 110 according to control from the PC 100.

  The illuminating device 120 is a device that irradiates light to the object 150 to be inspected, and can control the intensity of irradiated light in units of regions in accordance with a stripe pattern from the PC 100. Furthermore, the illuminating device 120 can control the intensity | strength of the light of the said area unit according to periodic time transition. In other words, the lighting device 120 can give a periodic temporal change and a spatial change of the light intensity. A specific light intensity control method will be described later.

  The screen 130 diffuses the light output from the illuminating device 120 and then irradiates the test object 150 with light in a plane. The screen 130 according to the present embodiment irradiates the object 150 in a surface with the light input from the illumination device 120 and subjected to periodic time change and space change. An optical system component (not shown) such as a condensing Fresnel lens may be provided between the illumination device 120 and the screen 130.

  In addition, although this embodiment demonstrates the example which comprises the planar irradiation part which combines the illuminating device 120 and the screen 130, and gives the periodic time change and spatial change of light intensity, such a combination is demonstrated. For example, the illumination unit may be configured by arranging LEDs in a plane.

  The time correlation camera 110 includes an optical system 210, an image sensor 220, a data buffer 230, a control unit 240, and a reference signal output unit 250. FIG. 2 is a block diagram showing the configuration of the time correlation camera 110 of the present embodiment.

  The optical system 210 includes a photographic lens and the like, transmits a light beam from a subject (including an object to be inspected) outside the time correlation camera 110, and forms an optical image of the subject formed by the light beam.

  The image sensor 220 is a sensor that can output the intensity of light incident through the optical system 210 as a light intensity signal at high speed for each pixel.

  The light intensity signal of the present embodiment is a signal obtained by the illumination device 120 of the inspection system irradiating a subject (including an object to be inspected) with light and the image sensor 220 receiving reflected light from the subject.

  The image sensor 220 is, for example, a sensor that can be read out at a higher speed than a conventional sensor, and has a two-dimensional planar shape in which pixels are arranged in two kinds of directions: a row direction (x direction) and a column direction (y direction). It shall be configured. Each pixel of the image sensor 220 is defined as a pixel P (1,1),..., P (i, j),..., P (X, Y) (Note that the image size in this embodiment is X X Y). Note that the reading speed of the image sensor 220 is not limited and may be the same as the conventional one.

  The image sensor 220 receives a light beam from a subject (including an object to be inspected) transmitted by the optical system 210 and photoelectrically converts the light intensity signal (photographing) indicating the intensity of light reflected from the subject. Signal) is generated and output to the control unit 240. The image sensor 220 according to the present embodiment outputs the frame for each readable unit time.

  The control unit 240 according to the present embodiment includes, for example, a CPU, a ROM, a RAM, and the like. By executing an inspection program stored in the ROM, the transfer unit 241, the reading unit 242, and the intensity image superimposing unit 243. And a first multiplier 244, a first correlation image superimposing unit 245, a second multiplier 246, a second correlation image superimposing unit 247, and an image output unit 248. Note that the present invention is not limited to implementation with a CPU or the like, and may be implemented with an FPGA or an ASIC.

  The transfer unit 241 stores the frames composed of the light intensity signals output from the image sensor 220 in the data buffer 230 in time series order.

  The data buffer 230 accumulates frames composed of light intensity signals output from the image sensor 220 in time series.

  FIG. 3 is a conceptual diagram showing frames accumulated in time series in the time correlation camera 110 of the present embodiment. As shown in FIG. 3, the data buffer 230 of the present embodiment stores a plurality of light intensity signals G (1, 1, t), every time t (t = t0, t1, t2,..., Tn). .., G (i, j, t),..., G (X, Y, t) are combined into a plurality of frames Fk (k = 1, 2,..., N) in chronological order. Accumulated. Note that one frame created at time t is a light intensity signal G (1, 1, t),..., G (i, j, t), ..., G (X, Y, t). Composed.

  A light intensity signal (imaging signal) G (1,1, t),..., G (i, j, t),. Each pixel P (1,1),..., P (i, j),..., P (X, Y) constituting k = 1, 2,.

  The frame output from the image sensor 220 includes only a light intensity signal, in other words, it can be considered as monochrome image data. In this embodiment, an example in which the image sensor 220 generates monochrome image data in consideration of resolution, sensitivity, cost, and the like will be described. However, the image sensor 220 is not limited to a monochrome image sensor. Alternatively, a color image sensor may be used.

  Returning to FIG. 2, the reading unit 242 of the present embodiment receives the light intensity signals G (1,1, t),..., G (i, j, t),. Y, t) are read out in frame-by-frame order and output to the first multiplier 244, the second multiplier 246, and the intensity image superimposing unit 243.

  The time correlation camera 110 of the present embodiment generates image data for each output destination of the reading unit 242. In other words, the time phase camera 110 creates three types of image data.

  The time correlation camera 110 of this embodiment generates intensity image data and two types of time correlation image data as three types of image data. Note that the present embodiment is not limited to generating three types of image data, and it may be possible to generate no intensity image data or to generate one or more types of time-correlated image data. .

  As described above, the image sensor 220 of the present embodiment outputs a frame composed of a light intensity signal every unit time. However, in order to generate normal image data, a light intensity signal corresponding to the exposure time necessary for photographing is required. Therefore, in the present embodiment, the intensity image superimposing unit 243 generates intensity image data by superimposing a plurality of frames for an exposure time necessary for photographing. In addition, each pixel value (value representing the intensity of light) G (x, y) of the intensity image data can be derived from the following equation (1). The exposure time is the time difference between t0 and tn.

  Thereby, the intensity image data in which the subject (including the object to be inspected) is photographed is generated in the same manner as the conventional camera photographing. Then, the intensity image superimposing unit 243 outputs the generated intensity image data to the image output unit 248.

  The time correlation image data is image data indicating changes in light intensity according to time transition. That is, in the present embodiment, for each frame in time series order, the light intensity signal included in the frame is multiplied by the reference signal indicating the time transition, and the reference signal, the light intensity signal, and the time that is the multiplication result Temporal correlation image data is generated by generating a temporal correlation value frame composed of correlation values and superimposing a plurality of temporal correlation value frames.

  By the way, in order to detect abnormality of the object to be inspected using the time correlation image data, it is necessary to change the light intensity signal input to the image sensor 220 in synchronization with the reference signal. For this purpose, as described above, the illumination device 120 performs planar light irradiation that periodically gives temporal changes and spatial movement of the stripes via the screen 130.

In this embodiment, two types of time correlation image data are generated. The reference signal may be a signal representing a time transition, but in the present embodiment, a complex sine wave e ^−jωt is used. It is assumed that the angular frequency is ω and the time is t. The angular frequency ω is such that the complex sine wave e ^−jωt representing the reference signal correlates with one period of the above-described exposure time (in other words, the time required to generate the intensity image data and the time correlation image). It shall be set. In other words, the planar and dynamic light formed by the illumination unit 120 and the illumination unit such as the screen 130 is in a first period (time period) at each position on the surface (reflection surface) of the inspection object 150. And a distribution of increase or decrease in spatial irradiation intensity in a second period (spatial period) along at least one direction along the surface. When this planar light is reflected by the surface, it is complex-modulated according to the specifications of the surface (normal vector distribution, etc.). The time correlation camera 110 receives the light complex-modulated on the surface and performs quadrature detection (orthogonal demodulation) using the reference signal of the first period, thereby obtaining time correlation image data as a complex signal. By modulation / demodulation based on such complex time correlation image data, it is possible to detect features corresponding to the surface normal vector distribution.

The complex sine wave e ^−jωt can also be expressed as e ^−jωt = cos (ωt) −j · sin (ωt). Accordingly, each pixel value C (x, y) of the time correlation image data can be derived from the following equation (2).

  In this embodiment, in the formula (2), two types of time correlation image data are divided into a pixel value C1 (x, y) representing the real part and a pixel value C2 (x, y) representing the imaginary part. Generate.

For this reason, the reference signal output unit 250 generates and outputs different reference signals for the first multiplier 244 and the second multiplier 246, respectively. Reference signal output section 250 of this embodiment outputs the first reference signal cosωt corresponding to the real part of the complex sine wave e ^-Jeiomegati the first multiplier 244, the imaginary part of the complex sine wave e ^-Jeiomegati The corresponding second reference signal sin ωt is output to the second multiplier 246. As described above, the reference signal output unit 250 according to the present embodiment describes an example in which two types of reference signals expressed as time functions of a sine wave and a cosine wave that form a Hilbert transform pair are described. Any reference signal that changes with time transition such as a function may be used.

Then, the first multiplier 244 ^calculates the real part cosωt of the complex sine wave e ^−jωt input from the reference signal output unit 250 for each light intensity signal of the frame in units of frames input from the reading unit 242. Multiply.

  The first correlation image superimposing unit 245 performs a process of superimposing the multiplication result of the first multiplier 244 on a pixel-by-pixel basis for a plurality of frames for an exposure time necessary for photographing. Thereby, each pixel value C1 (x, y) of the first time correlation image data is derived from the following equation (3).

The second multiplier 246 multiplies the light intensity signal of the frame input from the reading unit 242 by the imaginary part sin ^ωt of the complex sine wave e ^−jωt input from the reference signal output unit 250.

  The second correlation image superimposing unit 247 performs a process of superimposing the multiplication result of the second multiplier 246 on a pixel-by-pixel basis for a plurality of frames corresponding to the exposure time necessary for photographing. Thereby, each pixel value C2 (x, y) of the second time correlation image data is derived from the following equation (4).

  By performing the processing described above, two types of time correlation image data, in other words, time correlation image data having two degrees of freedom can be generated.

Further, the present embodiment does not limit the type of reference signal. For example, in this embodiment, two types of time-correlated image data of the real part and the imaginary part of the complex sine wave e ^−jωt are created, but two types of image data based on the light amplitude and the light phase are generated. May be.

  Note that the time correlation camera 110 of the present embodiment can create a plurality of systems as time correlation image data. Thereby, for example, when light in which stripes having a plurality of types of widths are combined is irradiated, two types of time correlation image data based on the real part and the imaginary part described above can be created for each stripe width. For this purpose, the time correlation camera 110 includes a combination of two multipliers and two correlation image superimposing units for a plurality of systems, and the reference signal output unit 250 has an angular frequency suitable for each system. The reference signal by ω can be output.

  Then, the image output unit 248 outputs two types of time correlation image data and intensity image data to the PC 100. As a result, the PC 100 detects an abnormality of the object to be inspected using the two types of time correlation image data and the intensity image data. For that purpose, it is necessary to irradiate the subject with light.

  The illuminating device 120 of this embodiment irradiates the fringe pattern which moves at high speed. FIG. 4 is a diagram illustrating an example of a fringe pattern irradiated by the illumination device 120 of the present embodiment. In the example shown in FIG. 4, the stripe pattern is scrolled (moved) in the x direction. A white area is a bright area corresponding to the stripe, and a black area is an interval area (dark area) corresponding to the stripe.

  In the present embodiment, the fringe pattern irradiated by the illuminating device 120 is moved by one cycle with the exposure time when the time correlation camera 110 captures the intensity image data and the time correlation image data. Thereby, the illuminating device 120 gives the time change of the light intensity periodically by the spatial movement of the stripe pattern of the light intensity. In the present embodiment, the time during which the fringe pattern in FIG. 4 moves by one period corresponds to the exposure time, so that each pixel of the time-correlated image data relates to at least the light intensity signal for one period of the fringe pattern. Information is embedded.

  As shown in FIG. 4, in the present embodiment, an example in which the illumination device 120 irradiates a stripe pattern based on a rectangular wave will be described, but other than a rectangular wave may be used. In the present embodiment, the illumination device 120 is irradiated through the screen 130, so that the bright and dark boundary region of the rectangular wave can be blurred.

  In the present embodiment, a stripe pattern irradiated by the illumination device 120 is represented as A (1 + cos (ωt + kx), that is, the stripe pattern includes a plurality of stripes repeatedly (periodically). The intensity of the light applied to can be adjusted between 0 and 2 A, and is the light phase kx, where k is the wave number of the stripes, and x is the direction in which the phase changes.

  The fundamental frequency component of the light intensity signal f (x, y, t) of each pixel in the frame can be expressed as the following equation (5). As shown in Expression (5), the brightness of the stripe changes in the x direction.

f (x, y, t) = A (1 + cos (ωt + kx))
= A + A / 2 {e ^{j (ωt + kx)} + e ^{−j (ωt + kx)} } (5)

  As shown in Expression (5), the intensity signal of the fringe pattern irradiated by the illumination device 120 can be considered as a complex number.

  Then, the light from the illumination device 120 is reflected and input to the image sensor 220 from the subject (including the object to be inspected).

  Therefore, the light intensity signal G (x, y, t) input to the image sensor 220 can be used as the light intensity signal f (x, y, t) of each pixel of the frame when the illumination device 120 is irradiated. Therefore, when Expression (5) is substituted into Expression (1) for deriving intensity image data, Expression (6) can be derived. The phase is kx.

  From Expression (6), it can be confirmed that each pixel of the intensity image data is input with a value obtained by multiplying the exposure time T by the intermediate value A of the intensity of the light output from the illumination device 120. Further, when Expression (5) is substituted into Expression (2) for deriving time correlation image data, Expression (7) can be derived. Note that AT / 2 is the amplitude and kx is the phase.

  Thereby, the time correlation image data shown by the complex number shown by Formula (7) is replaceable with the two types of time correlation image data mentioned above. That is, the above-described time correlation image data composed of the real part and the imaginary part includes a phase change and an amplitude change in the light intensity change irradiated to the object to be inspected. In other words, the PC 100 according to the present embodiment can detect the phase change of the light emitted from the illumination device 120 and the light amplitude change based on the two types of time correlation image data. Therefore, the PC 100 according to the present embodiment, based on the time correlation image data and the intensity image data, amplitude image data representing the amplitude of light entering each pixel and phase image data representing the phase change of light entering each pixel. And generate.

  Further, the PC 100 detects an abnormality of the object to be inspected based on the generated amplitude image data and phase image data.

  By the way, when an abnormality based on the unevenness occurs in the surface shape of the object to be inspected, a change corresponding to the abnormality occurs in the distribution of normal vectors on the surface of the object to be inspected. Further, when an abnormality that absorbs light occurs on the surface of the object to be inspected, the intensity of the reflected light changes. A change in the normal vector distribution is detected as at least one of a phase change and an amplitude change of light. Thus, in the present embodiment, using the time correlation image data and the intensity image data, at least one of the light phase change and the amplitude change corresponding to the change in the normal vector distribution is detected. Thereby, the abnormality of the surface shape can be detected. Next, the relationship between the abnormality of the inspected object, the normal vector, and the phase change or amplitude change of light will be described.

  FIG. 5 is a diagram illustrating a first detection example of abnormality of an object to be inspected by the time correlation camera 110 according to the first embodiment. In the example shown in FIG. 5, it is assumed that the inspected object 500 has a projecting shape abnormality 501. In this situation, it can be confirmed that the normal vectors 521, 522, and 523 are in different directions in the region near the point 502 of the abnormality 501. The normal vectors 521, 522, 523 are directed in different directions, so that diffusion (for example, light 511, 512, 513) is generated in the light reflected from the anomaly 501, and the image sensor 220 of the time correlation camera 110. The width 503 of the fringe pattern entering the arbitrary pixel 531 is increased.

  FIG. 6 is a diagram showing an example of the amplitude of light that changes in accordance with the abnormality 501 shown in FIG. In the example shown in FIG. 6, the amplitude of light is divided into a real part (Re) and an imaginary part (Im) and is represented on a two-dimensional plane. In FIG. 6, the light amplitudes 611, 612, and 613 corresponding to the lights 511, 512, and 513 in FIG. The light amplitudes 611, 612, and 613 cancel each other, and light having an amplitude 621 is incident on the arbitrary pixel 531 of the image sensor 220.

  Therefore, in the situation shown in FIG. 6, it can be confirmed that the amplitude is small in the region where the abnormality 501 of the inspection object 500 is imaged. In other words, when there is a region that is darker than the surroundings in the amplitude image data showing the change in amplitude, it can be assumed that there is a cancellation of the amplitude of light in the region, It can be determined that an abnormality 501 has occurred at the position of the corresponding inspection object 500.

  The inspection system according to the present embodiment is not limited to the one in which the inclination changes steeply like the abnormality 501 in FIG. 5, and can also detect an abnormality that changes gently. FIG. 7 is a diagram illustrating a second example of detection of abnormality of an object to be inspected by the time correlation camera 110 according to the first embodiment. In the example shown in FIG. 7, the surface of the object to be inspected is flat (in other words, the normal line is parallel) in the normal state, but a gentle gradient 701 is generated on the object 700 to be inspected. In such a situation, the normal vectors 721, 722, and 723 on the gradient 701 also change gently. Accordingly, the light beams 711, 712, and 713 input to the image sensor 220 are also shifted little by little. In the example shown in FIG. 7, since the light amplitudes do not cancel each other due to the gentle gradient 701, the light amplitudes shown in FIGS. 5 and 6 hardly change. However, although the light originally projected from the screen 130 should enter the image sensor as it is, the light projected from the screen 130 does not enter the image sensor in a parallel state because of the gentle gradient 701. A phase change occurs in the light. Accordingly, by detecting the difference between the light phase change and the surroundings, an abnormality due to the gentle gradient 701 as shown in FIG. 7 can be detected.

  In addition, there may be an abnormality other than the surface shape of the inspection object (in other words, the distribution of the normal vector of the inspection object). FIG. 8 is a diagram illustrating a third example of detection of abnormality of an object to be inspected by the time correlation camera 110 according to the first embodiment. In the example shown in FIG. 8, since the dirt 801 is attached to the object 800, the light irradiated from the illumination device 120 is absorbed or diffusely reflected, and the dirt 801 of the time correlation camera 110 is photographed. This shows an example in which light hardly changes in intensity in an arbitrary pixel region. In other words, in an arbitrary pixel area where the dirt 801 is photographed, the light intensity causes a phase cancellation, the vibration component is canceled, and an almost DC brightness is shown.

  In such a case, in the pixel region where the dirt 801 is imaged, there is almost no light amplitude, and therefore when the amplitude image data is displayed, a region darker than the surroundings is generated. Therefore, it can be estimated that there is an abnormality 801 such as dirt at the position of the inspection object 800 corresponding to the region.

  As described above, in the present embodiment, it is possible to estimate that the object to be inspected is abnormal by detecting the change in the amplitude of the light and the change in the phase of the light based on the time correlation image data.

  Returning to FIG. 1, the PC 100 will be described. The PC 100 controls the entire detection system. The PC 100 includes a movement mechanism control unit 101, an illumination control unit 102, a control unit 103, and a storage unit 109. The storage unit 109 stores data used for arithmetic processing, arithmetic processing results, and the like.

  The movement mechanism control unit 101 controls the movement mechanism 140 in order to change the surface of the object 150 to be imaged by the time correlation camera 110. The moving mechanism 140 is, for example, a robot arm. In the present embodiment, in the PC 100, a plurality of surfaces to be imaged of the inspection object 150 are set. Then, each time the time correlation camera 110 finishes capturing the object 150, the moving mechanism control unit 101 can capture the surface on which the time correlation camera 110 is set according to the setting. The inspection body 150 is moved. Note that this embodiment does not limit the movement mechanism 140 to be moved every time shooting is completed and stopped before shooting is started, and the movement mechanism 140 may be continuously driven. . The moving mechanism 140 can also be referred to as a conveyance unit, a moving unit, a gripping unit, a position changing unit, a posture changing unit, and the like.

  The illumination control unit 102 outputs a fringe pattern irradiated by the illumination device 120 in order to inspect the inspected object 150. The illumination control unit 102 of this embodiment transfers at least three or more stripe patterns to the illumination device 120 and instructs the illumination device 120 to switch and display the stripe patterns during the exposure time.

  FIG. 9 is a diagram illustrating an example of a fringe pattern output from the illumination control unit 102 to the illumination device 120. In accordance with the rectangular wave shown in FIG. 9B, the illumination control unit 102 performs control so that the stripe pattern in which the black region and the white region shown in FIG. 9A are set is output.

  In this embodiment, the stripe interval for each stripe pattern to be irradiated is set according to the size of the abnormality (defect) to be detected, and detailed description thereof is omitted here.

  In addition, the angular frequency ω of the rectangular wave for outputting the fringe pattern is set to the same value as the angular frequency ω of the reference signal.

  As shown in FIG. 9, the fringe pattern output from the illumination control unit 102 can be shown as a rectangular wave, but the border area of the fringe pattern is blurred through the screen 130, that is, the bright area in the fringe pattern. By making the intensity change of light at the boundary between the (stripe region) and the dark region (interval region) gentle (dull), it can be approximated to a sine wave. FIG. 10 is a diagram illustrating an example of a wave shape representing a stripe pattern after passing through the screen 130. As shown in FIG. 10, the measurement accuracy can be improved by the wave shape approaching a sine wave. Further, a gray region in which the brightness changes in multiple steps may be added to the stripe, or a gradation may be given. Further, a stripe pattern including color stripes may be used.

  Returning to FIG. 1, the control unit 103 includes an amplitude-phase image generation unit 104 and an abnormality detection processing unit 105, and by intensity image data input from the time correlation camera 110 and time correlation image data, Processing is performed to calculate a feature corresponding to the distribution of the normal vector on the surface to be inspected of the inspected object 150 and detecting an abnormality based on the difference from the surroundings. In the present embodiment, in order to perform the inspection, two types of real number and imaginary part of complex number correlation image data are used instead of time correlation image data (referred to as complex time correlation image data) indicated by complex numbers. Are received from the time correlation camera 110.

  The amplitude-phase image generation unit 104 generates amplitude image data and phase image data based on the intensity image data input from the time correlation camera 110 and the time correlation image data.

  The amplitude image data is image data representing the amplitude of light entering each pixel. The phase image data is image data representing the phase of light entering each pixel.

  Although the present embodiment does not limit the calculation method of the amplitude image data, for example, the amplitude-phase image generation unit 104 has pixel values C1 (x, y) and C2 (x, From y), each pixel value F (x, y) of the amplitude image data can be derived using Equation (8).

  In the present embodiment, it is possible to determine whether there is a region where an abnormality has occurred based on the pixel value (amplitude) of the amplitude image data and the pixel value of the intensity image data. For example, an abnormality occurs in a region where the value obtained by dividing the pixel value (AT) of the intensity image data by 2 and the amplitude of the amplitude image data (which is AT / 2 when cancellation does not occur) to some extent I can guess that it is not. On the other hand, it can be presumed that the amplitude cancellation occurs in the non-matching region. A specific method will be described later.

  Similarly, the amplitude-phase image generation unit 104 uses the pixel values C1 (x, y) and C2 (x, y) to calculate each pixel value P (x, y) of the phase image data using Equation (9). Can be derived.

  The abnormality detection processing unit 105 is a feature corresponding to the distribution of the normal vector on the inspection symmetry plane based on the amplitude image data and the phase image data generated by the amplitude-phase image generation unit 104, and is based on a difference from the surroundings. Then, a feature related to the abnormality of the inspection object 150 is detected. In the present embodiment, an example in which the amplitude distribution of the complex time correlation image is used as the feature corresponding to the distribution of the normal vector will be described. The amplitude distribution of the complex time correlation image is data indicating the amplitude distribution of each pixel of the complex time correlation image, and corresponds to amplitude image data.

  Next, the abnormality detection process based on the amplitude in the abnormality detection processing unit 105 of the present embodiment will be described. FIG. 11 is a flowchart showing a procedure of the processing in the abnormality detection processing unit 105 of the present embodiment.

  First, the abnormality detection processing unit 105 determines the average amplitude of the N × N region from the light amplitude value (representing pixel value) stored in each pixel of the amplitude image data, with the pixel as a reference (for example, the center). The value is subtracted (step S1101), and average difference image data of amplitude is generated. The average difference image data of the amplitude corresponds to the gradient of the amplitude. The integer N is set to an appropriate value depending on the embodiment.

  Next, the abnormality detection processing unit 105 performs a mask process using a predetermined amplitude threshold value on the average difference image data of the amplitude generated by the subtraction (step S1102).

  Further, the abnormality detection processing unit 105 calculates a standard deviation for each pixel within the mask area of the average difference image data (step S1103). In the present embodiment, a method based on the standard deviation will be described. However, the method is not limited to the case where the standard deviation is used. For example, an average value or the like may be used.

  Then, the abnormality detection processing unit 105 detects a pixel whose amplitude pixel value obtained by subtracting the average is smaller than −4.5σ (σ: standard deviation) as a region having an abnormality (defect) (step S1104).

  By the processing procedure described above, an abnormality of the object to be inspected can be detected from the amplitude value of each pixel (in other words, the amplitude distribution). However, the present embodiment is not limited to detecting an abnormality from the amplitude distribution of the complex time correlation image. The gradient of the phase distribution may be used as a feature corresponding to the distribution of normal vectors on the inspection symmetry plane. An example using the gradient of the phase distribution will be described next.

  Next, the abnormality detection process based on the phase in the abnormality detection processing unit 105 of the present embodiment will be described. FIG. 12 is a flowchart showing a procedure of the processing in the abnormality detection processing unit 105 of the present embodiment.

  First, the abnormality detection processing unit 105 subtracts the average phase value of the N × N region from the phase value of the light of each pixel of the phase image data (a pixel value representing the pixel value) using the pixel as a reference (for example, the center). (Step S1201), phase average difference image data is generated. The phase average difference image data corresponds to the phase gradient.

  Next, the abnormality detection processing unit 105 compares the magnitude (absolute value) of the average difference image data of the phase generated by the subtraction with a threshold value, and determines pixels whose average difference image data size is equal to or greater than the threshold value. Then, it is detected as an abnormal (defect) pixel (step S1202).

  Based on the detection result of S1202, the abnormality detection processing unit 105 can determine the unevenness based on the sign of the average difference image data, that is, the magnitude relationship between the phase value of the pixel and the average phase value (step S1203). Which of the pixel phase value and the average phase value is convex depends on the setting of each part, but the unevenness differs if the magnitude relationship is different.

  An abnormality can be detected from the gradient of the phase distribution obtained by another method. For example, as another method, the abnormality detection processing unit 105 determines whether the difference between the average vector of the N × N region of the normalized time correlation image data and the normalized vector of each pixel is a threshold value. If it is larger than that, it can be detected as a pixel having an abnormality (defect). Further, the abnormality of the object to be inspected may be detected based on information corresponding to the phase distribution, not limited to the gradient of the phase distribution.

  Next, the abnormality detection process based on the amplitude and intensity in the abnormality detection processing unit 105 of the present embodiment will be described. FIG. 13 is a flowchart showing a procedure of the processing in the abnormality detection processing unit 105 of the present embodiment.

  First, the abnormality detection processing unit 105 uses the following equation (100) for each pixel from the time correlation image data and the intensity image data, and uses the following equation (100) to represent the amplitude (representing pixel value) C (x, y) (equation ( 7)) and intensity (a pixel value representing) G (x, y) (see equation (6)) R (x, y) is calculated (step S1301).

R (x, y) = C (x, y) / G (x, y) (100)

  Next, the abnormality detection processing unit 105 compares the ratio R (x, y) with a threshold value, and sets a pixel having a ratio R (x, y) value equal to or less than the corresponding threshold value to a pixel having an abnormality (defect). (Step S1302). In addition, the abnormality detection processing unit 105 compares the ratio R (x, y) with a threshold value, and determines that a pixel whose ratio R (x, y) is equal to or greater than another corresponding threshold value is uneven (dirt or the like). A pixel is detected (step S1303). When the cancellation of the amplitude (attenuation) becomes significant due to an abnormality in the distribution of the normal vector, the amplitude decreases more than the strength. On the other hand, although there is not so much abnormality in the normal vector distribution, when the light absorption becomes significant due to dirt on the surface of the object 150 to be inspected, the intensity is greatly reduced compared to the amplitude. Therefore, the abnormality detection processing unit 105 can detect the abnormality type in steps S1302 and S1303.

  Next, an inspection process for an object to be inspected in the inspection system of the present embodiment will be described. FIG. 14 is a flowchart showing a procedure of the above-described processing in the inspection system of the present embodiment. It is assumed that the inspected object 150 is already fixed to the moving mechanism 140 and is disposed at the initial position of the inspection.

  The PC 100 of this embodiment outputs a fringe pattern for inspecting the object to be inspected to the illumination device 120 (step S1401).

  The illuminating device 120 stores the fringe pattern input from the PC 100 (step S1421). And the illuminating device 120 displays the stored fringe pattern so that it may change according to a time transition (step S1422). Note that the conditions under which the illuminating device 120 starts display are not limited when the fringe pattern is stored, and may be, for example, when the inspector performs a start operation on the illuminating device 120.

  Then, the control unit 103 of the PC 100 transmits a shooting start instruction to the time correlation camera 110 (step S1402).

  Next, the time correlation camera 110 starts imaging for an area including the inspection object 150 in accordance with the transmitted imaging instruction (step S1411). Next, the control unit 240 of the time correlation camera 110 generates intensity image data and time correlation image data (step S1412). Then, the control unit 240 of the time correlation camera 110 outputs the intensity image data and the time correlation image data to the PC 100 (step S1413).

  The control unit 103 of the PC 100 receives the intensity image data and the time correlation image data (step S1403). Then, the amplitude-phase image generation unit 104 generates amplitude image data and phase image data from the received intensity image data and time correlation image data (step S1404).

  Then, the abnormality detection processing unit 105 performs abnormality detection control of the inspected object based on the amplitude image data and the phase image data (step S1405). Then, the abnormality detection processing unit 105 outputs the abnormality detection result to a display device (not shown) included in the PC 100 (step S1406).

  As an output example of the abnormality detection result, the intensity image data is displayed, and an area of the intensity image data corresponding to the area where the abnormality is detected based on the amplitude image data and the phase image data is displayed. For example, a decorative display may be used so that it can be recognized. Further, the output is not limited to visual output, and it may be output that an abnormality has been detected by voice or the like.

  The control unit 103 determines whether or not the inspection of the object to be inspected is completed (step S1407). If it is determined that the inspection has not been completed (step S1407: No), the moving mechanism control unit 101 captures the surface of the inspection object to be inspected with the time correlation camera 110 in accordance with a predetermined setting. The movement control of the arm is performed so that it can be performed (step S1408). After the arm movement control is completed, the control unit 103 transmits an imaging start instruction to the time correlation camera 110 again (step S1402).

  On the other hand, if the control unit 103 determines that the inspection of the object to be inspected has ended (step S1407: Yes), the control unit 103 outputs an end instruction to the time correlation camera 110 (step S1409) and ends the process.

  Then, the time correlation camera 110 determines whether an end instruction has been received (step S1414). If an end instruction has not been received (step S1414: NO), the processing is performed again from step S1411. On the other hand, if an end instruction has been received (step S1414: YES), the process ends.

  Note that the inspecting process of the illumination device 120 may be performed by an inspector, or may be ended in accordance with an instruction from another configuration.

  In the present embodiment, the example in which the intensity image data generated using the time correlation camera 110 and the time correlation image data are generated has been described. However, the present invention is not limited to the use of the time correlation camera 110 for generating the intensity image data and the time correlation image data, and a time correlation camera that can be realized by analog processing or an operation equivalent thereto. An imaging system may be used. For example, image data generated by a normal digital still camera is output, and the information processing apparatus superimposes a reference signal using the image data generated by the digital still camera as frame image data, thereby generating time-correlated image data. The time correlation image data may be generated by using a digital camera that superimposes a reference signal on a light intensity signal in the image sensor.

(Modification 1)
In this embodiment, an example in which a feature related to an abnormality is detected based on a difference from the surroundings has been described, but the present invention is not limited to detecting the feature based on a difference from the surroundings. The feature may be detected based on a difference from data (reference data such as time correlation data, amplitude image data, phase image data, etc.). In this case, it is necessary to align and synchronize the spatial phase modulation illumination (stripe pattern) with the reference data.

  In this modification, the abnormality detection processing unit 105 stores the amplitude image data and phase image data obtained from the reference surface, the amplitude image data and phase image data of the inspected object 150, which are stored in the storage unit 109 in advance. Are compared to determine whether there is a difference greater than or equal to a predetermined standard for any one or more of the light amplitude and the light phase between the surface of the inspection object 150 and the reference surface.

  This modification is an example in which an inspection system having the same configuration as that of the first embodiment is used and the surface of a normal object to be inspected is used as a reference surface.

  While the illuminating device 120 irradiates the fringe pattern through the screen 130, the time correlation camera 110 images the surface of a normal object to be inspected and generates time correlation image data. Then, the PC 100 receives the time correlation image data generated by the time correlation camera 110, generates amplitude image data and phase image data, and stores the amplitude image data and phase image data in the storage unit 109 of the PC 100. . Then, the time correlation camera 110 captures an object to be inspected for determining whether or not an abnormality has occurred, and generates time correlation image data. Then, the PC 100 generates the amplitude image data and the phase image data from the time correlation image data, and then compares the amplitude image data and the phase image data with the amplitude image data and the phase image data of the normal inspection object stored in the storage unit 109. At that time, the comparison result of the amplitude image data and phase image data of a normal inspection object and the amplitude image data and phase image data of the inspection object to be inspected is data indicating characteristics for detecting an abnormality. Output. Then, when the feature for detecting an abnormality is equal to or greater than the predetermined reference, it can be estimated that the inspection object 150 is abnormal.

  Thereby, in this modification, it can be determined whether there is a difference from the surface of the normal object to be inspected, in other words, whether there is an abnormality on the surface of the object to be inspected. Note that any method may be used as a method for comparing the amplitude image data and the phase image data, and thus description thereof is omitted.

  Furthermore, in the present modification, an example in which data indicating characteristics for detecting an abnormality is output based on the difference from the reference surface has been described, but the difference from the reference surface and the surroundings described in the first embodiment A feature for detecting an abnormality may be calculated by combining the differences. Since any method may be used as the method of combination, description thereof is omitted.

(Modification 2)
In the first embodiment, the example in which the fringe pattern is moved in the x direction to detect an abnormality (defect) of the inspection object has been described. However, when an abnormality (defect) in which the normal distribution changes sharply in the y direction perpendicular to the x direction is generated in the inspection object, the fringe pattern is moved in the y direction rather than in the x direction. It may be easier to detect defects. Therefore, in the modification, an example will be described in which a fringe pattern moving in the x direction and a fringe pattern moving in the y direction are alternately switched.

  The illumination control unit 102 of this modification switches the fringe pattern output to the illumination device 120 at predetermined time intervals. Thereby, the illuminating device 120 outputs the some fringe pattern extended in the different direction with respect to one test object surface.

  FIG. 15 is a diagram illustrating an example of switching the fringe pattern output by the illumination control unit 102 of the present modification. In FIG. 15A, the illumination control unit 102 changes the stripe pattern displayed by the illumination device 120 in the x direction. Thereafter, as illustrated in (B), the illumination control unit 102 causes the stripe pattern displayed by the illumination device 120 to transition in the y direction.

  And the control part 103 of PC100 performed abnormality detection based on the time correlation image data obtained from the stripe pattern irradiation of FIG. 15 (A), and obtained from the stripe pattern irradiation of FIG. 15 (B). Abnormality detection is performed based on the time correlation image data.

  FIG. 16 is a diagram illustrating an example in which the illumination control unit 102 according to the present modification irradiates a surface including an abnormality (defect) 1601 with a fringe pattern. In the example shown in FIG. 16, an abnormality (defect) 1601 extends in the x direction. In this case, the illumination control unit 102 sets the fringe pattern to move in the y direction that intersects the x direction, in other words, in the direction that intersects the longitudinal direction of the abnormality (defect) 1601. With this setting, detection accuracy can be improved.

  FIG. 17 is a diagram showing the relationship between the abnormality (defect) 1701 and the stripe pattern on the screen 130 when the stripe pattern is changed in the y direction, in other words, in the direction orthogonal to the longitudinal direction of the defect 1701. As shown in FIG. 17, when an abnormality (defect) 1701 having a narrow width in the y direction and a longitudinal direction in the x direction intersecting the y direction occurs, the light emitted from the illumination device 120 is In the y direction that intersects the x direction, the cancellation of the amplitude of light increases. Therefore, the PC 100 can detect the abnormality (defect) from the amplitude image data corresponding to the stripe pattern moved in the y direction.

  In the inspection system of this modification, when the longitudinal direction of the defect generated in the inspection object is random, the fringe pattern is displayed in a plurality of directions (for example, the x direction and the y direction crossing the x direction). Thus, the defect can be detected regardless of the shape of the defect, and the detection accuracy of the abnormality (defect) can be improved. Further, by projecting a fringe pattern that matches the shape of the abnormality, the abnormality detection accuracy can be improved.

(Modification 3)
In addition, the second modification described above is not limited to the method of switching the fringe pattern when performing abnormality detection in the x direction and abnormality detection in the y direction. Therefore, in Modification 3, an example in which the stripe pattern output from the illumination control unit 102 to the illumination device 120 is moved simultaneously in the x direction and the y direction will be described.

  FIG. 18 is a diagram illustrating an example of a fringe pattern that the illumination control unit 102 according to the present modification outputs to the illumination device 120. In the example shown in FIG. 18, the illumination control unit 102 moves the fringe pattern in the direction 1801.

  The stripe pattern shown in FIG. 18 includes a stripe pattern with one period 1802 in the x direction and a stripe pattern with one period 1803 in the y direction. That is, the stripe pattern shown in FIG. 18 has a plurality of stripes extending in crossing directions having different widths. It is necessary to make the width of the stripe pattern in the x direction different from the width of the stripe pattern in the y direction. Thereby, when generating the time correlation image data corresponding to the x direction and the time correlation image data corresponding to the y direction, the corresponding reference signals can be made different. In addition, since the period (frequency) of the change in the intensity of light due to the stripe pattern may be changed, the moving speed of the stripe pattern (stripe) may be changed instead of changing the width of the stripe.

  Then, the time correlation camera 110 generates time correlation image data corresponding to the stripe pattern in the x direction based on the reference signal corresponding to the stripe pattern in the x direction, and based on the reference signal corresponding to the stripe pattern in the y direction. Thus, time correlation image data corresponding to the stripe pattern in the y direction is generated. After that, the control unit 103 of the PC 100 detects an abnormality based on the time correlation image data corresponding to the stripe pattern in the x direction, and then detects an abnormality based on the time correlation image data corresponding to the stripe pattern in the y direction. I do. Thereby, in this modification, it becomes possible to detect regardless of the direction in which the defect occurs, and the detection accuracy of the abnormality (defect) can be improved.

<Calibration of control position and control attitude by moving mechanism>
As shown in FIG. 1, the control unit 103 of the PC 100 of the inspection system calibrates the control position and control posture of the object 150 to be inspected by the moving mechanism 140, so that the parameter acquisition unit 106, the interval detection unit 107, A parameter calculation unit 108 and the like are included. The functions of these units will be described later. In the present embodiment, the PC 100 also functions as a calibration system that performs calibration. The calibration is performed in a state where the moving mechanism 140 supports the reflecting member 160 instead of the inspection object 150. The reflective member 160 may also be referred to as a reference member, a reference member, a calibration member, an alignment member, and the like, and the reflective surface 161 may also be referred to as a reference surface, a reference surface, a calibration surface, an alignment surface, and the like. In the calibration system, the position and orientation of the moving mechanism 140 may be detected by the sensor 141.

  FIG. 19 is an exemplary schematic diagram of the arrangement of the screen 130, the reflection member 160, and the time correlation camera 110 when calibration using the reflection member 160 is performed. In order to obtain a time correlation image of the reflecting surface 161 of the reflecting member 160, for example, a fringe pattern that moves along the direction Dp is projected onto the screen 130. The light with the fringe pattern projected on the screen 130 functioning as an illumination unit enters the reflection surface 161, is reflected by the reflection surface 161, and enters the time correlation camera 110. The control unit 103 uses an arithmetic process based on the time correlation image of the reflecting surface 161 to set the inspection target surface (inspected surface) of the inspection object 150 to a predetermined inspection position and inspection posture (inspection angle) during inspection. A control parameter for the moving mechanism 140 is calculated. At this time, the control unit 103 can calculate the control parameter based on the time correlation image of the reflection surface 161 of the reflection member 160 having a plurality of positions P1 and P2 and posture.

  An example of the reflecting member 160 is shown in FIGS. 20 is a front view of the reflecting surface 161, and FIG. 21 is a side view of the reflecting member 160 as viewed from below in FIG. In the reflecting member 160, a plurality of concave portions 163 having the same width and extending along the first direction (the vertical direction in FIG. 20 and the direction perpendicular to the paper surface in FIG. 21) are orthogonal to the first direction. Are arranged at a constant interval (pitch) in the second direction (the left-right direction in FIGS. 20 and 21). The width of the recess 163 and the distance between the two recesses 163 and 163 adjacent to each other are set to be the same. In other words, the reflecting member 160 has a plurality of convex portions 164 having the same width and extending along the first direction (the vertical direction in FIG. 20 and the direction perpendicular to the paper surface in FIG. 21). Are arranged at a constant interval (pitch) in a second direction (left-right direction in FIGS. 20 and 21) orthogonal to the first direction.

  In the reflective surface 161, the top surface of the convex portion 164 is configured as the first reflective surface 161a, and the bottom surface of the concave portion 163 is configured as the second reflective surface 161b. The plurality of first reflecting surfaces 161a are arranged on a first virtual plane (not shown), and the plurality of second reflecting surfaces 161b are on a second virtual plane (not shown) parallel to the first virtual plane. Is arranged. That is, the first reflecting surface 161a and the second reflecting surface 161b are parallel. Moreover, both the 1st reflective surface 161a and the 2nd reflective surface 161b are comprised as a mirror surface.

  At a boundary portion between the first reflecting surface 161a and the second reflecting surface 161b, a pointed portion 162 extending along the first direction (vertical direction in FIG. 20) is provided. The point 162 is an example of a shape discontinuity. In addition, although the recessed part 163 is comprised by the 2nd reflective surface 161b as a bottom face, and a pair of side surface orthogonal to the 2nd reflective surface 161b, it is not limited to this, For example, a bottom face and a side face The corner between the two may be a curved surface, or may form a curved surface in which a bottom surface and a pair of side surfaces are continuous. Further, in the pointed portion 162, the first reflecting surface 161a and the side surface of the recess 163 form a right angle, but the bottom surface and the side surface may form an angle of 180 ° or less on the substantial side, not the right angle. May be. In addition, the apex 162 may be referred to as a corner, a ridge, or a ridge line.

  In FIG. 22, the directions of incident light and reflected light with respect to the reflecting surface 161 are illustrated in an enlarged state as compared with FIG. In FIG. 22, the light emitted from the screen 130 (not shown) enters the reflecting surface 161 along the direction Di to the right in FIG. The stripe pattern extends in a direction perpendicular to the paper surface of FIG. 22, and moves on the reflective surface 161 toward the lower right side and the lower side of FIG. 22. The reflected light from the reflecting surface 161 travels along the direction Dr downward in FIG. 22 and enters a time correlation camera 110 (not shown in FIG. 22).

  In the configuration and arrangement illustrated in FIG. 22, the optical path greatly changes between the upper side (left side) and the lower side (right side) of FIG. Therefore, in the time correlation image (phase image) of the reflective surface 161, a phase discontinuity (a large change) occurs at a position (line) corresponding to the cusp 162. A phase discontinuity (phase discontinuity) in the time correlation image can be detected by a calculation process on the time correlation image. Specifically, for example, it can be detected as a position where the phase gradient in the time correlation image is larger than a predetermined threshold. Here, in the case of FIG. 22, the interval between the phase discontinuities (phase discontinuity lines) corresponding to the two adjacent cusps 162 in the time correlation image is between the two adjacent cusps 162. This is proportional to the distance D in the direction Ds perpendicular to the optical axis of the image sensor of the time correlation camera 110. This distance D varies depending on the position and posture of the reflecting surface 161. For example, when the reflecting member 160 and the reflecting surface 161 are rotated slightly clockwise from the state of FIG. 22, the distance D in that state becomes narrower than the distance D in the state of FIG. Conversely, when the reflecting member 160 and the reflecting surface 161 are slightly rotated counterclockwise from the state of FIG. 22, the distance D in that state becomes wider than the distance D in the state of FIG. Thereby, in the time correlation image, it is possible to calculate the position and orientation of the reflecting surface 161 by detecting the interval between two phase discontinuities adjacent to each other and performing a geometric operation based on the interval. I understand. In this case, the control unit 103 may calculate the position and orientation of the reflecting surface 161 based on the time correlation image of the reflecting surface 161 at a plurality of positions and orientations. Note that regarding the calibration, a small change in the characteristics of the time correlation image based on scratches on the reflecting surface 161 need not be considered.

  FIG. 23 shows an example of the calibration procedure. That is, the control unit 103 first functions as the parameter acquisition unit 106 and acquires the control parameters of the moving mechanism 140 corresponding to the position and orientation in a state where calibration is performed using the reflection member 160 ( S1). The control parameter may be a control command value or a value detected by the sensor 141. Next, the control unit 103 functions as the interval detection unit 107, and between two adjacent phase discontinuity parts (phase discontinuity lines) in the time correlation image of the reflection surface 161 obtained by the time correlation camera 110. Is detected (S2). Next, the control unit 103 functions as the parameter calculation unit 108 and calculates a control parameter of the moving mechanism 140 at the time of inspection (S3). In S3, for example, the control unit 103 first calculates the position and orientation of the reflecting surface 161 from the geometric calculation based on the interval detected in S2. Next, the parameter calculation unit 108 calculates the calculated position and orientation of the reflecting surface 161, the correlation between the previously acquired position and orientation of the reflecting surface 161 and the control parameter of the moving mechanism 140, and the inspected object 150. Control parameters for setting each inspection target surface (inspected surface) of the inspection object 150 to a predetermined inspection position and inspection posture are calculated from specifications such as shape and size. Then, the control unit 103 stores the calculated control parameter in the storage unit 109 (S4). The moving mechanism control unit 101 can use the control parameters stored in the storage unit 109 at the time of inspection.

  As described above, in the present embodiment, for example, a reflective member having a reflective surface 161 provided with a plurality of cusps 162 (shape discontinuities) that cause phase discontinuities in a time correlation image. 160 is used. The interval detection unit 107 detects the interval between the discontinuous portions of the phase in the time correlation image obtained by imaging the reflection surface 161, and the parameter calculation unit 108 detects the inspection target surface at the time of inspection based on the detected interval. A parameter corresponding to at least one of the position and orientation is calculated. Therefore, according to the present embodiment, for example, a control position and a control posture for performing an inspection at a position and posture with less inconvenience for the inspected object 150 using the reflecting member 160 having a prescribed shape. Calibration can be performed. Therefore, according to the present embodiment, it is possible to perform inspection with higher accuracy or higher efficiency.

  In the present embodiment, the reflecting surface 161 has a plurality of cusps 162 parallel to each other. Therefore, for example, the posture in the direction in which the interval between the cusps 162 changes can be calibrated.

  In the present embodiment, the reflective surface 161 is provided with a plurality of recesses 163 parallel to each other. Therefore, for example, the reflecting surface 161 provided with the pointed portion 162 can be obtained relatively easily.

<Modified example of reflecting member>
24 and 25 illustrate the reflective member 160A of the first modification. As shown in FIGS. 24 and 25, in the reflecting member 160A, the recesses 163 having the same width and the same interval are arranged in a lattice shape in the vertical direction and the horizontal direction. Thereby, the some convex part 164 of the same width as the recessed part 163 is arrange | positioned at lattice point shape. In FIG. 24, for convenience, the concave portion 163 is hatched. The cross-sectional shapes of the concave portion 163 and the convex portion 164 are the same as those of the reflecting member 160 shown in FIGS. According to the reflecting member 160A, a plurality of parallel cusps 162 (for example, first cusps) extending in the vertical direction in FIG. 24 can be obtained, and a plurality of parallel cusps extending in the left-right direction in FIG. 162 (eg, a second apex) can be obtained. Therefore, according to this modification, two stripe patterns orthogonal to each other, that is, a first stripe pattern that moves along the direction Dp2 that moves along the direction Dp1, and a direction that moves along the direction Dp2. Using the second stripe pattern extending along Dp1, the position and orientation of the inspection target surface (surface to be inspected) can be calibrated in two directions orthogonal to each other.

  FIG. 26 illustrates a reflective member 160B of the second modified example. The arrangement of the concave portions 163 and the convex portions 164 of the reflecting member 160B of FIG. 26 is opposite to that of the reflecting member 160A shown in FIGS. That is, in the reflecting member 160B, the convex portions 164 having equal widths and equal intervals are arranged in a lattice pattern in the vertical direction and the horizontal direction. Thereby, the several recessed part 163 of the same width as the convex part 164 is arrange | positioned at lattice point shape. In FIG. 26, the concave portion 163 is hatched. The same effect as that of the reflective member 160A can be obtained by the reflective member 160B. That is, also according to this modification, two stripe patterns orthogonal to each other, that is, a first stripe pattern that moves along the direction Dp2 that moves along the direction Dp1, and a direction Dp1 that moves along the direction Dp2 The position and orientation of the inspection target surface (surface to be inspected) can be calibrated in two directions orthogonal to each other using the second stripe pattern extending along.

  27 and 28 illustrate a reflective member 160C of the third modification. As shown in FIGS. 27 and 28, the reflecting member 160 </ b> C has a triangular cross section and extends in a first direction (the vertical direction in FIG. 27, the direction perpendicular to the paper surface in FIG. 28). In other words, a plurality of parallel recesses having a triangular cross section and extending in the first direction are provided, and a plurality of parallel cusps 162 are formed as ridge lines of the protrusions. Is provided. Then, two mirror-like plane portions 161c and 161d having different normal directions are provided so as to be adjacent to each other with the pointed portion 162 interposed therebetween. Also in this case, the same effects as those of the above embodiment and the modification can be obtained.

  The inspection program and the calibration program executed by the PC 100 according to the above-described embodiment are files in an installable or executable format, such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), and the like. And recorded on a computer-readable recording medium.

  Further, the inspection program and the calibration program executed by the PC 100 according to the above-described embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Moreover, you may comprise so that the test | inspection program and calibration program which are performed with PC100 of embodiment mentioned above may be provided or distributed via networks, such as the internet.

  Although some embodiments and modifications of the present invention have been described, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and modifications can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 100 ... PC (inspection system, calibration system) 101 ... Movement mechanism control part (control part), 104 ... Amplitude-phase image generation part (time correlation image generation part), 105 ... Abnormality detection processing part (arithmetic processing part), DESCRIPTION OF SYMBOLS 107 ... Space | interval detection part, 108 ... Parameter calculation part, 110 ... Time correlation camera, 120 ... Illuminating device (illuminating part), 130 ... Screen (illuminating part), 140 ... Moving mechanism, 160 ... Reflecting member, 161, 161a, 161b ... reflecting surface, 162 ... point (discontinuous shape).

Claims (7)

A planar illumination unit that gives periodic temporal and spatial changes in light intensity, a time correlation image generation unit that generates a time correlation image by a time correlation camera or an imaging system that operates equivalently, and the time correlation An arithmetic processing unit that calculates a feature corresponding to the distribution of the normal vector of the surface to be inspected from the image and that detects a feature based on at least one of a difference from the surroundings and a difference from the reference surface Calibration system for an inspection system,
A reflective member having a reflective surface provided with a plurality of shape discontinuities that cause phase discontinuities in the time correlation image;
In the time correlation image obtained by imaging the reflection surface, an interval detection unit that detects an interval between discontinuous portions of the phase;
A parameter calculation unit that calculates a parameter corresponding to at least one of the position and orientation of the inspection target surface at the time of inspection based on the detected interval;
A calibration system comprising:   The calibration system according to claim 1, wherein the reflective surface has a plurality of cusps parallel to each other as the shape discontinuity.   The shape discontinuity portion has a first apex extending along a first direction and a second apex extending along a second direction intersecting the first direction. Item 3. The calibration system according to Item 1 or 2.   The calibration system according to claim 1, wherein the reflective surface is provided with a plurality of recesses parallel to each other.   The calibration system according to any one of claims 1 to 3, wherein the reflection surface includes a plurality of plane portions that are adjacent to each other with the shape discontinuity portion and have different normal directions.   The reflection member used with the calibration system as described in any one of Claims 1-5. A planar illumination unit that provides periodic temporal and spatial changes in light intensity;
A time correlation image generating unit that generates a time correlation image by a time correlation camera or an imaging system that performs an equivalent operation;
An arithmetic processing unit that calculates a feature that detects an abnormality based on at least one of a difference from the surroundings and a difference from the reference surface, which is a feature corresponding to the distribution of normal vectors on the inspection target surface from the time correlation image; ,
Based on the calculation result of the time correlation image obtained by imaging the reflection surface of the reflecting member having the reflection surface provided with the plurality of shape discontinuities that cause the phase discontinuity in the time correlation image. A control unit for controlling at least one of the position and orientation of the inspection target surface;
With inspection system.

Images