JP2006329898A - Measuring method and device of surface distortion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect surface distortion without visual observation by an inspector. <P>SOLUTION: A surface distortion determining device 30 collates a photographed image of an actual reflected pattern formed on a surface of a panel P by irradiation of a test pattern with a simulation image representing an ideal reflected pattern, quantitatively measures the degree of surface distortion of the panel P based on the gap between the actual reflected pattern and the ideal reflected pattern, and determines the pass-fail of the surface distortion according to a predetermined determination reference, based on the degree of the measured surface distortion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface strain measurement method and a measurement apparatus for measuring the surface strain of an object such as an automobile body.

  Conventionally, the pass / fail determination in the surface quality inspection of an automobile body or the like is performed by sensory determination of an inspector. As a sensory determination method, for example, a visual inspection called a highlight inspection is known. This highlight inspection forms a striped light pattern on the surface of the object by irradiating the object with light from a plurality of fluorescent lamps arranged in parallel at regular intervals, and the flow pattern of the light pattern. This is a method for inspecting the surface distortion of an object. A light beam pattern formed on the surface of an object in this highlight inspection is usually called a highlight line.

  Patent Document 1 discloses a method of projecting a striped image on the surface of a mirror-coated panel from an oblique direction, visually evaluating the disturbance of the striped image projected on the panel surface, and evaluating the distortion of the panel. ing.

  In Patent Document 2, the surface to be measured is irradiated with light beams of seven colors parallel to each other, and the light beams of seven colors are moved perpendicularly to the light beams on the surface to be measured. A method for detecting distortion is disclosed.

Japanese Patent Laid-Open No. 11-153420 JP-A-5-315530

  However, in the above method, since the visual inspection is performed by the inspector, the inspection results vary depending on the inspector's ability difference, fatigue level, inspection environment, and the like. When variation occurs in the sensory determination, there is a possibility that an object that should actually be rejected may be determined to be acceptable, or an object that should be acceptable may be determined to be unacceptable. As a result, an object that should be rejected may be left uncorrected, or a time loss may be caused by arranging to correct the object that should be acceptable.

  Therefore, the present invention provides a surface strain measurement method and a measurement apparatus that make it possible to inspect a surface strain without visual inspection by an inspector.

  The surface strain measurement method according to the present invention is a surface strain measurement method for measuring the surface strain of an object, and a photographed image of an actual pattern formed on the surface of the object by irradiation of a test pattern; A simulation image representing an ideal pattern is collated, and the degree of surface distortion of the object is quantitatively measured based on the deviation between the actual pattern and the ideal pattern.

  In a preferred aspect of the present invention, the acceptance / rejection of the surface strain of the object is further determined according to a predetermined criterion based on the measured degree of surface strain.

  The surface strain measuring device according to the present invention is a surface strain measuring device for measuring the surface strain of an object, and obtains a photographed image of an actual pattern formed on the surface of the object by irradiation of a test pattern. A captured image acquisition means, a simulation image acquisition means for acquiring a simulation image representing an ideal pattern formed on the surface of the object by irradiation of the test pattern, a captured image acquired by the captured image acquisition means, A measurement unit that compares the simulation image acquired by the simulation image acquisition unit and quantitatively measures the degree of surface distortion of the object based on the deviation between the actual pattern and the ideal pattern. It is characterized by.

  In a preferred aspect of the present invention, the apparatus further includes a determination unit that determines whether or not the surface strain of the object is acceptable according to a predetermined determination criterion based on the degree of the surface strain measured by the measurement unit.

  ADVANTAGE OF THE INVENTION According to this invention, the measuring method and measuring apparatus of a surface strain which make it possible to test | inspect a surface strain without visual inspection by an inspector can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a surface strain determination system 1 including a surface strain measurement device according to the present embodiment. The surface strain determination system 1 is used for surface quality inspection of an automobile body or the like, and quantitatively determines the pass / fail of the surface strain of an object (here, a panel P of a vehicle). In FIG. 1, the surface strain determination system 1 includes an imaging system 10, a simulation device 20, and a surface strain determination device 30.

  The imaging system 10 is a system that irradiates a panel P with a predetermined test pattern and thereby images a reflection pattern formed on the surface of the panel P. The imaging system 10 includes a test pattern irradiation device 11 and a reflection pattern imaging device 12.

  The test pattern irradiation device 11 is a device that irradiates the panel P with a predetermined test pattern. Here, the test pattern irradiation device 11 irradiates the surface of the panel P with a predetermined angle from a predetermined position with striped light beams from a plurality of fluorescent lamps 11a arranged in parallel at regular intervals. Thereby, a striped light ray / shadow pattern is formed on the surface of the panel P as a reflection pattern. Each light ray portion or shadow portion constituting this light ray / shadow pattern is called a highlight line.

  The reflection pattern imaging device 12 captures a reflection pattern formed on the surface of the panel P by irradiating a test pattern to obtain a captured image. Here, the reflection pattern imaging device 12 is a CCD camera that captures, as data, an image of a highlight line formed on the surface of the panel P from a predetermined position at a predetermined angle.

  The simulation device 20 is a device that generates a simulation image representing an ideal reflection pattern formed on the surface of the panel P by irradiation with a test pattern. Specifically, the simulation apparatus 20 is a computer that generates a simulation image representing a virtual reflection pattern formed on the surface of the virtual panel P by irradiation with a virtual test pattern by three-dimensional modeling. . Preferably, the simulation image is zebra line image data of a design design used for design evaluation at the design stage. Further, a mold for the panel P is created based on the data of the virtual panel P, and the actual panel P is manufactured using the mold.

  Specifically, the simulation apparatus 20 renders the three-dimensional model data of the panel P based on the light source condition (light source position, number, size, direction, etc.) and the viewpoint condition (viewpoint position, direction, etc.). By performing the processing, a simulation image that is two-dimensional image data is created. Here, the three-dimensional model data of the panel P includes three-dimensional shape data (including a plurality of coordinate values, for example) representing the three-dimensional shape of the panel P, and optical characteristics (reflectance, etc.) of the surface of the panel P. Optical characteristic data shown. The three-dimensional model data may be created by the simulation device 20 or may be created externally and taken into the simulation device 20. The light source condition and the viewpoint condition may be input from the outside or may be set in advance. The rendering process preferably includes a projection conversion process, a hidden surface removal process, and a shading process. The projection conversion process is a process of projecting a three-dimensional model defined by three-dimensional model data onto a two-dimensional plane (projection plane) based on viewpoint conditions by coordinate conversion calculation. The hidden surface erasure processing is processing for erasing a surface (hidden surface) that is hidden behind the object when viewed from the viewpoint, and is realized by, for example, a Z buffer method or a scan line method. The shading process is a process of calculating a shadow based on the light source condition and the viewpoint condition to add a shadow to the three-dimensional model, and is realized by, for example, a glow shading method or a von shading method. Since these processes are widely known, detailed description thereof is omitted here.

  Preferably, the simulation apparatus 20 is a CAD (Computer Aided Design) apparatus, and creates zebra line image data using a widely known zebra mapping function or highlight line display function.

  The surface strain determination device 30 is a device that quantitatively measures the degree of surface strain of the panel P and quantitatively determines whether the surface strain is acceptable based on the measured degree of surface strain. Here, the surface strain determination device 30 is configured by a computer including a CPU, ROM, RAM, hard disk, and the like, and the function thereof is realized by a CPU executing a predetermined program stored in a storage medium such as a ROM. The In FIG. 1, the surface distortion determination apparatus 30 includes a captured image acquisition unit 31, a simulation image acquisition unit 32, a measurement unit 33, and a determination unit 34 as functional blocks.

  The captured image acquisition unit 31 acquires a captured image of an actual reflection pattern captured by the imaging system 10.

  The simulation image acquisition unit 32 acquires a simulation image representing an ideal reflection pattern generated by the simulation device 20.

  The measurement unit 33 collates the captured image acquired by the captured image acquisition unit 31 with the simulation image acquired by the simulation image acquisition unit 32, and based on the difference between the actual reflection pattern and the ideal pattern. The degree of surface distortion of the panel P is quantitatively measured.

  The determination unit 34 determines whether or not the surface strain of the panel P is acceptable according to a predetermined criterion based on the degree of the surface strain measured by the measurement unit 33.

  FIG. 2 is a flowchart showing an operation procedure of the surface strain determination device 30. Hereinafter, the operation of the surface strain determination apparatus 30 will be specifically described with reference to FIG.

  The simulation image acquisition unit 32 acquires zebra line image data of a design design as a simulation image from the simulation apparatus 20 via a communication line, a recording medium, or the like (S1).

  The captured image acquisition unit 31 acquires CCD camera image data of a highlight line as a captured image from the imaging system 10 via a communication line or a recording medium (S2).

  The measurement unit 33 includes an image (zebra line image) indicated by the zebra line image data of the design design acquired in step S1 and an image (highlight) indicated by the CCD camera image data of the highlight line acquired in step S2. The line CCD camera image) is overlaid and collated (S3). At this time, the measurement unit 33 appropriately performs coordinate conversion processing or the like on the zebra line image data or the CCD camera image data to unify the dimensions and orientations of the zebra line image and the highlight line CCD camera image. Further, the measurement unit 33 converts the zebra line and the highlight line into lines having no width so that the zebra line included in the zebra line image can be compared with the highlight line included in the highlight line CCD camera image. replace. FIG. 3 is a diagram illustrating an example of an image in which a zebra line image and a highlight line CCD camera image are superimposed. In FIG. 3, a solid line represents a zebra line, and a broken line represents a highlight line. In FIG. 3, the highlight line is deviated from the zebra line, and it can be seen that the panel P has surface distortion.

  Next, the measurement unit 33 calculates the degree of surface distortion of the panel P based on the deviation between the zebra line and the highlight line in the image superimposed in step S3 (S4). Specifically, as shown in FIGS. 4A and 4B, the measurement unit 33 has a range of how many mm between the zebra line and the highlight line in each of the vertical direction and the horizontal direction of the image. The number of mm deviations, that is, the deviation range and the deviation amount are quantified.

  The determination unit 34 determines whether or not the surface distortion of the panel P is acceptable (OK or NG) according to a predetermined determination criterion based on the shift range and the shift amount digitized in step S4 (S5). For example, the determination unit 34 classifies the surface strain level from A zone to C zone according to the part / part according to the part / part determination criterion, and follows the comprehensive determination standard based on the level classification result for each part / part. The final pass / fail for panel P is determined. Here, it is preferable that the determination criterion is set according to the vehicle grade in accordance with market needs. The determination result of the determination unit 34 is output as appropriate, for example, displayed on a display screen.

  In addition, when surface distortion inspection is performed for a plurality of panels P of the same type, after the process of step S1 is executed only once, the processes of steps S2 to S5 are repeated a plurality of times.

  As described above, in the present embodiment, a captured image of an actual pattern formed on the surface of an object by irradiation of a test pattern is compared with a simulation image representing an ideal pattern, The degree of surface distortion of the object is quantitatively measured based on the deviation from the ideal pattern. For this reason, according to this Embodiment, it becomes possible to determine quantitatively the pass / fail of the surface distortion of a target object based on the degree of the surface distortion measured quantitatively.

  Further, according to the present embodiment, since the pass / fail of the surface strain is determined according to a predetermined determination criterion based on the degree of the surface strain quantitatively measured, the surface is not determined by a sensory determination such as visual inspection by an inspector. Strain inspection can be performed. As a result, variations in determination of surface distortion can be eliminated.

  In addition, this invention is not limited to the said embodiment, It can change variously within the range which does not deviate from the summary of this invention. For example, the test pattern irradiated on the object is preferably a striped pattern, but may be another pattern such as a lattice pattern. In the above embodiment, the deviation range and the deviation amount are measured as the degree of the surface strain. However, other amounts of the degree of the surface distortion such as the area of the region surrounded by the zebra line and the highlight line are measured. May be measured.

It is a figure which shows the structure of the surface strain determination system containing the surface strain measuring apparatus which concerns on embodiment. It is a flowchart which shows the operation | movement procedure of a surface distortion determination apparatus. It is a figure which shows an example of the image on which the zebra line image and the highlight line CCD camera image were superimposed. It is a figure which shows the deviation | shift range and deviation | shift amount about each of the vertical direction of an image, and a horizontal direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Surface distortion determination system, 10 Imaging system, 11 Test pattern irradiation apparatus, 12 Reflection pattern imaging apparatus, 20 Simulation apparatus, 30 Surface distortion determination apparatus, 31 Captured image acquisition part, 32 Simulation image acquisition part, 33 Measurement part, 34 determination Department, P Panel (object).

Claims (4)

A surface strain measurement method for measuring the surface strain of an object,
Based on the difference between the actual pattern and the ideal pattern by comparing the captured image of the actual pattern formed on the surface of the object with the test pattern irradiation and the simulation image representing the ideal pattern. A method for measuring surface strain, characterized by quantitatively measuring the degree of surface strain of an object. The method for measuring surface strain according to claim 1,
Furthermore, based on the degree of the measured surface strain, whether or not the surface strain of the object is acceptable is determined according to a predetermined determination criterion. A surface strain measuring device for measuring the surface strain of an object,
A captured image acquisition means for acquiring a captured image of an actual pattern formed on the surface of the object by irradiation of the test pattern;
Simulation image acquisition means for acquiring a simulation image representing an ideal pattern formed on the surface of the object by irradiation of the test pattern;
By comparing the captured image acquired by the captured image acquisition means with the simulation image acquired by the simulation image acquisition means, the degree of surface distortion of the object is determined based on the deviation between the actual pattern and the ideal pattern. A measuring means for quantitative measurement;
An apparatus for measuring surface strain, comprising: The surface strain measuring device according to claim 3,
An apparatus for measuring surface strain, further comprising determination means for determining whether or not the surface strain of the object is acceptable based on a degree of surface strain measured by the measurement means in accordance with a predetermined determination criterion.

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