WO1991005984A1 - Procede et dispositif de determination du sens longitudinal de copeaux de bois et analogue - Google Patents

Procede et dispositif de determination du sens longitudinal de copeaux de bois et analogue

Info

Publication number
WO1991005984A1
WO1991005984A1 PCT/FI1990/000243 FI9000243W WO9105984A1 WO 1991005984 A1 WO1991005984 A1 WO 1991005984A1 FI 9000243 W FI9000243 W FI 9000243W WO 9105984 A1 WO9105984 A1 WO 9105984A1
Authority
WO
WIPO (PCT)
Prior art keywords
chip
longitudinal direction
chips
shadows
wood chips
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/FI1990/000243
Other languages
English (en)
Inventor
Seppo Korhonen
Pertti Puumalainen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IGGESUND PULP FIBRE Oy AB
Original Assignee
IGGESUND PULP FIBRE Oy AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IGGESUND PULP FIBRE Oy AB filed Critical IGGESUND PULP FIBRE Oy AB
Publication of WO1991005984A1 publication Critical patent/WO1991005984A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes

Definitions

  • the present invention relates to a method of determining the longitudinal direction of wood chips or the like comprising at least one ridge on at least one surface of the chip, wherein said surface is illuminated and imaged by a detector.
  • the invention is also concerned with a device for realizing the method.
  • logs are chopped in a chopper into chips which are transported on a conveyor belt to the cooking step.
  • the chopper knives are adjusted so that the length of the result- ing chips is suitable for cooking.
  • the length of a chip means its dimension in the fibre direction.
  • Chips on the conveyor belt are therefore sampled at regular intervals ,and their length is measured.
  • the object of the present invention is to provide a simple and reliable method of determining the longitudinal direction of wood chips and the like.
  • the main characteristic features of the method are disclosed in the attached claim 1.
  • the present invention utilizes ridges formed by fibres on the two opposite surfaces of a chip. By obliquely illuminating such a surface, shadows are created behind the fibre ridges. The longitudinal direction of the chips is then determined by imaging these shadows by a detector.
  • the method is simple and can be realized by a device described in the Finnish Patent Application titled "A method and a device for measuring the height of a piece of material", filed on the same day as the present patent application. It has proved that a suitable direction of illuminating wood chips is characterized in that said surface of the chip is illuminated in a direction forming an angle between 20° and 50°, preferably an angle of 35°, with the main plane of the surface.
  • the present invention is also concerned with a device for determining the longitudinal direction of wood chips or the like comprising at least one ridge on at least one surface of the chip, the device com ⁇ prising a source of light for illuminating said sur- face of the chip, and a detector for imaging the illuminated surface.
  • a device for determining the longitudinal direction of wood chips or the like comprising at least one ridge on at least one surface of the chip, the device com ⁇ prising a source of light for illuminating said sur- face of the chip, and a detector for imaging the illuminated surface.
  • Figure 1 is a general side view of a device of the invention.
  • Figure 2 is a planar view of the device.
  • Figure 1 shows a wood chip 1 which rests in an arbitrary position on a conveyor belt 2.
  • One broad surface 3 of the chip faces the conveyor belt while the opposite surface 4 faces upwards.
  • a source of light formed by one or more lamps 7 is provided above the plane of the conveyor belt 2 to illuminate the upper surface 4 of the chip.
  • a camera 8 is also positioned above the plane of the conveyor belt 2 to image the upper surf ce 4 of the chip 1. The camera is preferably directed downwards substan ⁇ tially perpendicular to the main plane of the surface
  • the light beams thus form an acute angle, i.e. an angle smaller than 90° with respect to the main plane of the surface 4, which, with wood chips, is substantially parallel with the conveyor belt.
  • the ridges 5 cast narrow shadows 9 on the surface 4. These narrow shadows are parallel with the wood fibres.
  • the longitudinal direction of the chips is determined b ' recording these shadows with the camera 8.
  • the grooves 6 extend perpendicular to the light beams from the lamp 7, whereby the shadows 9 are of the maximum width.
  • the shadows are the narrower the closer the direction of the ridges and the grooves is to the direction of the light beams from the lamp. If a chip lies on the conveyor belt in such a way that the ridges and the grooves are parallel with the light beams, no shadows are formed on the side surface 4.
  • the fibre direction of the chip can nevertheless be determined, because it is known that the fibres are in this case parallel with the light beams.
  • the inclination of the light beams with respect to the upper surface 4 of the chip is selected so that shadows 9 of a suitable width are obtained. The inclination thereby varies with the shape of the sur ⁇ face.
  • an angle between 20" and 50°, preferably an angle of 35A be ⁇ tween the light beams and the surface 4 is suitable.
  • the surface 4 of the chip is parallel with the surface of the conveyor belt 2, so that the angle between the light beams and the conveyor belt is sub- stantially equal to that between the light beams and the surface 4.
  • the invention has been described with reference to wood chips, but the in ⁇ vention can also be applied to determine the longitudinal direction of any other material pieces in which at least one surface comprises at least one ridge.
  • the word ridge may even refer to the edge of a groove.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

Procédé et dispositif de détermination du sens longitudinal de copeaux de bois ou analogue. La longueur des copeaux produits par un couperet, fournit des informations sur le fonctionnement du couperet. La longueur des copeaux détermine leur dimension dans le sens des fibres, ce qui a été auparavant mesuré manuellement puisque les dispositifs de mesure automatique ne pouvaient pas fair la distinction entre la longueur et la largeur des copeaux. Si une surface (4) de copeaux cassés d'une pièce de bois est éclairée obliquement à partir du dessus, les nervures (5) des fibres produisent des ombres étroites (9) sur la surface (4). Par imagerie de ces ombres à l'aide d'une caméra (8) le dispositif obtient des informations sur le sens longitudinal du copeau.
PCT/FI1990/000243 1989-10-18 1990-10-17 Procede et dispositif de determination du sens longitudinal de copeaux de bois et analogue Ceased WO1991005984A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI894961A FI894961A7 (fi) 1989-10-18 1989-10-18 Menetelmä ja laite hakepalojen ja sentapaisten pituussuunnan toteamiseksi
FI894961 1989-10-18

Publications (1)

Publication Number Publication Date
WO1991005984A1 true WO1991005984A1 (fr) 1991-05-02

Family

ID=8529184

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1990/000243 Ceased WO1991005984A1 (fr) 1989-10-18 1990-10-17 Procede et dispositif de determination du sens longitudinal de copeaux de bois et analogue

Country Status (2)

Country Link
FI (1) FI894961A7 (fr)
WO (1) WO1991005984A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015111128A (ja) * 2014-12-19 2015-06-18 キヤノン株式会社 位置姿勢計測装置、位置姿勢計測方法、およびプログラム

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976382A (en) * 1972-11-14 1976-08-24 A/S Kongsberg Vapenfabrik Procedure and apparatus for determining the geometrical shape of a surface
GB2032618A (en) * 1978-09-18 1980-05-08 Eastman Kodak Co Inspection of elongate articles for surface irregularities

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976382A (en) * 1972-11-14 1976-08-24 A/S Kongsberg Vapenfabrik Procedure and apparatus for determining the geometrical shape of a surface
GB2032618A (en) * 1978-09-18 1980-05-08 Eastman Kodak Co Inspection of elongate articles for surface irregularities

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015111128A (ja) * 2014-12-19 2015-06-18 キヤノン株式会社 位置姿勢計測装置、位置姿勢計測方法、およびプログラム

Also Published As

Publication number Publication date
FI894961A0 (fi) 1989-10-18
FI894961A7 (fi) 1991-04-19

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