Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
  • G01B11/167—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by projecting a pattern on the object
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
  • G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
  • G01B11/2518—Projection by scanning of the object
  • G01B11/2522—Projection by scanning of the object the position of the object changing and being recorded
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/8806—Specially adapted optical and illumination features
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
  • G01N21/8914—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the material examined
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
  • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
  • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
  • G01N21/898—Irregularities in textured or patterned surfaces, e.g. textiles, wood
  • G01N21/8986—Wood
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/46—Wood
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T7/00—Image analysis
  • G06T7/0002—Inspection of images, e.g. flaw detection
  • G06T7/0004—Industrial image inspection
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T7/00—Image analysis
  • G06T7/50—Depth or shape recovery
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T7/00—Image analysis
  • G06T7/50—Depth or shape recovery
  • G06T7/55—Depth or shape recovery from multiple images
  • G06T7/586—Depth or shape recovery from multiple images from multiple light sources, e.g. photometric stereo
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/56—Cameras or camera modules comprising electronic image sensors; Control thereof provided with illuminating means
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/90—Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2207/00—Indexing scheme for image analysis or image enhancement
  • G06T2207/10—Image acquisition modality
  • G06T2207/10024—Color image
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2207/00—Indexing scheme for image analysis or image enhancement
  • G06T2207/10—Image acquisition modality
  • G06T2207/10028—Range image; Depth image; 3D point clouds
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2207/00—Indexing scheme for image analysis or image enhancement
  • G06T2207/30—Subject of image; Context of image processing
  • G06T2207/30108—Industrial image inspection
  • G06T2207/30161—Wood; Lumber

Definitions

• Patent Document 2 states that stripes appear in the captured image due to vibrations of the test object that occur when the test object passes over the inspection surface of the displacement sensor, but that by taking the difference between the first displacement data and the second displacement data, it is possible to obtain an image in which the change in surface height caused by the vibrations of the test object is offset.
• the shape of the plywood in the thickness direction measured at a location other than the gap between the conveyors is a shape measured without being affected by vibrations that occur when the plywood overcomes the gap and is transported, and defects due to deformation of the plywood are detected based on depth information corrected on the basis of this shape information.
• the first lighting/imaging units 1F and 1B each include a first lighting and an imaging device.
• the first lighting irradiates a first lighting light for color image capture.
• the first lighting light can be composed of visible light such as white, blue, or green.
• the first lighting/imaging units 1F and 1B are installed vertically above and below the gap 51 of the belt conveyors 5U and 5D, and irradiate the first lighting light vertically toward the front and back of the plywood 10 located in the gap 51. That is, the first lighting/imaging unit 1F installed above the gap 51 irradiates the first lighting light toward the front of the plywood 10 located in the gap 51.
• the first lighting/imaging unit 1B installed below the gap 51 irradiates the first lighting light toward the back of the plywood 10 located in the gap 51.
• first lighting/imaging unit 1F, 1B in which the first lighting and imaging device are integrally provided has been shown here, the first lighting and imaging device may also be configured as separate entities.
• the shape measuring units 3F, 3B correspond to the shape measuring device in the claims, and are installed in a location different from the gap 51 in the conveying direction of the belt conveyors 5U, 5D to measure the shape in the thickness direction of the plywood 10 and generate shape information.
• the shape measuring units 3F, 3B are installed at positions vertically above and below the gap 51 at a sufficient distance on the downstream belt conveyor 5D side.
• a position on the downstream belt conveyor 5D that is sufficiently away from the gap 51 is a position where the plywood 10 can be stably conveyed without being affected by bouncing at the gap 51.
• Figure 3A shows a state in which the portion of the plywood 10 near the tip on the downstream side in the conveying direction is located in the gap 51, and the portion near the tip is lower than the reference position. Therefore, the depth information of the plywood 10 is obtained as information indicating a shape that is recessed downward from the reference position. The portion near the tip of the plywood 10 continues to descend until the tip of the plywood 10 rests on the downstream belt conveyor 5D, as shown in Figure 3B. Therefore, the depth information also continues to recess downward.
• the correction processing unit 44 corrects the depth information acquired by the depth information acquisition unit 42 based on the shape information acquired by the shape information acquisition unit 43. For example, when the shape in the thickness direction of the plyboard 10 indicated by the depth information acquired by the imaging device of the first lighting and imaging units 1F, 1B differs from the shape in the thickness direction of the plyboard 10 indicated by the shape information acquired by the laser displacement sensor of the shape measurement units 3F, 3B at the same position as the position where the depth information was acquired, the correction processing unit 44 corrects the depth information based on the shape information.
• the position where the depth information is acquired and the position where the shape information is acquired are the same means that the position of the plywood 10 photographed by the imaging device in the gap 51 of the belt conveyors 5U, 5D are the same as the position of the plywood 10 measured after the plywood 10 is transported from there to the position of the shape measurement units 3F, 3B.
• the same position on the plywood 10 can be identified, for example, based on the transport distance after the end of the plywood 10 is detected by the captured image. Alternatively, it can also be identified from the transport distance from the first lighting/imaging units 1F, 1B to the shape measurement units 3F, 3B and the transport speed of the belt conveyor 5.
• the correction processing unit 44 calculates the difference between the depth information and the shape information at the same position described above, and corrects the depth information by using the difference as a correction value for the depth information.
• FIG. 5 is a diagram for explaining the processing content of this correction processing unit 44.
• FIG. 5 shows the depth information D1, D2 generated by the first illumination and imaging units 1F, 1B as in FIG. 3 and the shape information F1, F2 generated by the shape measurement units 3F, 3B as in FIG. 4, superimposed so that the same positions correspond to each other.
• the depth information D1, D2 is corrected in such a way that defects such as warping or bending of the plywood 10 are not removed by the correction, and only the differences from the actual shape of the plywood 10 are removed.
• the corrected depth information accurately represents the shape of the plywood 10, similar to the shape information F1, F2 in FIG. 4.
• the depth information D1, D2 is corrected when the shape of the plywood 10 indicated by the depth information D1, D2 differs from the shape of the plywood 10 indicated by the shape information F1, F2, but the depth information D1, D2 may be corrected without determining whether the shapes differ.
• correction is performed by setting the difference value between the depth information D1, D2 and the shape information F1, F2 to zero, which is essentially equivalent to correcting the depth information D1, D2 only for the parts where the shapes are different.
• the defect detection unit 45 detects multiple types of defects in the plywood 10 based on the flat color image acquired by the color image acquisition unit 41.
• the multiple types of defects detected based on the flat color image include discoloration (mold, dirt, bark inclusion, etc.) on the front and back surfaces of the plywood 10, blind holes, loopholes, insect holes, dirt inclusion, and piled-up dirt. Note that these defects can be detected by applying known technology, and detailed explanations will be omitted.
• the defect detection unit 45 detects defects due to deformation such as warping or bending of the plywood 10 based on the depth information acquired by the depth information acquisition unit 42.
• the defect detection unit 45 detects defects such as warping or bending of the plywood 10 based on the corrected depth information.
• the corrected depth information accurately represents the shape of the plywood 10, making it possible to accurately detect defects such as warping or bending.
• step S2 it is determined whether acquisition of the planar color image, depth information, and shape information for the entire plywood 10 has been completed, and if not, the process returns to step S1 to continue. On the other hand, if it is determined that acquisition of information for the entire plywood 10 has been completed, the correction processing unit 44 corrects the depth information based on the shape information (step S3). Then, the defect detection unit 45 detects multiple types of defects in the plywood 10 based on the color image, and detects defects due to deformation such as warping or bending of the plywood 10 based on the corrected depth information (step S4). This completes the process of the flowchart shown in Figure 6.
• the defect inspection system according to the modified example is provided with side image capture devices 6L, 6R on the left and right sides at a sufficient distance from the gap 51 toward the downstream belt conveyor 5D.
• the distance from the gap 51 to the positions where the side image capture devices 6L, 6R are installed is the same as the distance from the gap 51 to the positions where the shape measurement units 3F, 3B are installed.
• FIGS. 7(b) and (c) in the defect inspection system according to the modified example, only one set of shape measurement units 3F, 3B is provided at the central position in the width direction of the downstream belt conveyor 5D. Note that three or more sets may be provided, as in FIG. 1.
• the shape measurement units 3F, 3B and the side image capture devices 6L, 6R are all installed on the downstream belt conveyor 5D side, but one or both may be installed on the upstream belt conveyor 5U side.

Landscapes

• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Immunology (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Pathology (AREA)
• Textile Engineering (AREA)
• Computer Vision & Pattern Recognition (AREA)
• Wood Science & Technology (AREA)
• Theoretical Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Quality & Reliability (AREA)
• Food Science & Technology (AREA)
• Medicinal Chemistry (AREA)
• Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
• Length Measuring Devices By Optical Means (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=95395512

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Citations (6)

Family Cites Families (1)

• 2024
  • 2024-09-03 JP JP2025509159A patent/JP7763448B2/ja active Active
  • 2024-09-03 FI FI20265194A patent/FI20265194A1/en unknown
  • 2024-09-03 WO PCT/JP2024/031552 patent/WO2025079367A1/ja active Pending
  • 2024-09-03 US US19/133,259 patent/US12602765B2/en active Active

Patent Citations (6)

Also Published As

Similar Documents

Legal Events