CA2298335A1 - Wood differentiating system - Google Patents
Wood differentiating system Download PDFInfo
- Publication number
- CA2298335A1 CA2298335A1 CA 2298335 CA2298335A CA2298335A1 CA 2298335 A1 CA2298335 A1 CA 2298335A1 CA 2298335 CA2298335 CA 2298335 CA 2298335 A CA2298335 A CA 2298335A CA 2298335 A1 CA2298335 A1 CA 2298335A1
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- CA
- Canada
- Prior art keywords
- wood
- lumber
- line
- computer
- laser
- 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.)
- Abandoned
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Classifications
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- 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
- 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
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Textile Engineering (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
A wood differentiating system comprising a line-forming laser, a camera and a computer is described herein. The line-forming laser projects a line of laser light onto wood lumber and the camera takes a picture of the illuminated area of the wood lumber. By determining the width of the scattered light in the fibres of the wood lumber, the computer is capable of differentiating between lumbers made of fir and lumbers made of spruce, for example.
Description
TITLE OF THE INVENTION
WOOD DIFFERENTIATING SYSTEM
FIELD OF THE INVENTION
The present invention relates to wood differentiating systems. More specifically, the present invention is concerned with a system designed to differentiate different species of wood.
BACKGROUND OF THE INVENTION
The similar geographic range and common occurrence of mixed strands of spruce and fir, for example in Eastern Canada and Northeast United States, has led to the practice of harvesting these two species without separation.
Since spruce and fir demonstrate different drying time and shrinkage potential, kiln drying schedules must be based on the longest drying time, i.e. the drying time of fir, to ensure complete drying of the mixed load. Of course, this often results in over-drying of the spruce lumber whose tendency towards twisting is thereby increased, leading to the downgrading of the spruce lumber.
There is therefore a need for a wood differentiating system designed to efficiently and cost effectively differentiate between different species of wood, such as, for example, spruce and fir, before they are further processed.
OBJECTS OF THE INVENTION
An object of the present invention is therefore to provide a wood differentiating system.
Other objects, advantages and features of the present invention will become more apparent upon reading of the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWIN S
In the appended drawings:
Figure 1 is a schematic view of a wood differentiating system according to an embodiment of the present invention;
Figure 2 is a schematic view of a spruce lumber as seen from the camera of the system of Figure 1; and Figure 3 is a schematic view of fir lumber as seen from the camera of the system of Figure 1.
WOOD DIFFERENTIATING SYSTEM
FIELD OF THE INVENTION
The present invention relates to wood differentiating systems. More specifically, the present invention is concerned with a system designed to differentiate different species of wood.
BACKGROUND OF THE INVENTION
The similar geographic range and common occurrence of mixed strands of spruce and fir, for example in Eastern Canada and Northeast United States, has led to the practice of harvesting these two species without separation.
Since spruce and fir demonstrate different drying time and shrinkage potential, kiln drying schedules must be based on the longest drying time, i.e. the drying time of fir, to ensure complete drying of the mixed load. Of course, this often results in over-drying of the spruce lumber whose tendency towards twisting is thereby increased, leading to the downgrading of the spruce lumber.
There is therefore a need for a wood differentiating system designed to efficiently and cost effectively differentiate between different species of wood, such as, for example, spruce and fir, before they are further processed.
OBJECTS OF THE INVENTION
An object of the present invention is therefore to provide a wood differentiating system.
Other objects, advantages and features of the present invention will become more apparent upon reading of the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWIN S
In the appended drawings:
Figure 1 is a schematic view of a wood differentiating system according to an embodiment of the present invention;
Figure 2 is a schematic view of a spruce lumber as seen from the camera of the system of Figure 1; and Figure 3 is a schematic view of fir lumber as seen from the camera of the system of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Generally stated, the embodiment of the present invention described hereinbelow has been developed to differentiate between spruce and fir using the principle of light and color scattering in the wood. The wood lumber is illuminated by a line-forming laser and at least one image is captured by a camera. The width of the light scattered along the fibres of the wood is measured and averaged to differentiate between spruce and fir. This information is then used to mechanically separate the spruce and fir lumber for further processing.
Turning now to Figure 1 of the appended drawings, a wood differentiating system 10 according to an embodiment of the present invention will be described.
The wood difFerentiating system 10 includes a computer 12 provided with a monitor 14, a sensor 16, a line-forming laser 18 and a camera 20. The sensor 16, laser 18 and camera 20 are connected to the computer 12.
As can be seen from this figure, the sensor 16, laser 18 and camera 20 are mounted above a conveyor assembly 22 that transversally moves lumbers 24 (see arrows 26).
The sensor 16 is so mounted that it detects a leading edge of a lumber 24 and transfers this data to the computer 12. The laser 18 is so mounted that the line it projects is upon a lumber when the leading edge of this lumber is detected by the sensor 16. The camera 20 is so mounted that it may capture images of the laser line on the lumber when the lumber is detected by the sensor 16.
The'bidirectional link between the camera 20 and the computer 12 is such that the computer may trigger the camera 20 and receive images therefrom for further processing. Similarly, the link between the laser 18 and the computer 12 allows the computer to control the state of the laser. It is to be noted that the link between the laser 18 and the computer 12 is optional. Indeed, the laser 18 could be powered on when the system 10 is energized and powered on a continuous basis without control by the computer.
Turning now to Figure 4 of the appended drawings, illustrating a schematic flow chart of the computer program running in the computer 12, and to Figures 2-3 illustrating images taken by the camera 20, the operation of the wood differentiating system 10 will be described.
The first step is the start of the wood differentiating system 10 (step 100). The system is then initialized in step 102. In step 104, the system waits for the sensor 16 to detect the front edge of a lumber 24.
When a lumber 24 is detected, the system 10 is ready to take a predetermined number N of pictures of the scattered light from the line producing laser 18. In step 106, a counter ("number of pictures") is set to zero (0) before a first image is taken (step 108). The "number of pictures" counter is then incremented in step 110.
The picture is then processed to remove the portion of the image that is directly illuminated by the laser 18 (step 112). This directly illuminated portion is identified by numeral 30 in Figures 2 and 3.
The remaining of the illuminated portion (see numerals 32 and 34 in 5 Figures 2 and 3, respectively) of the lumber is therefore illuminated due to the scattered light along the fibres of the wood.
In step 114, the width of the scattered light on both sides of the laser line is averaged. This width is represented by arrows 36 and 38 in Figures 2 and 3, respectively.
The system then verifies if the "number of pictures"
counter is equal to the predetermined number N of pictures to be taken (step 116). If this is not the case, steps 108-116 are repeated until N
pictures have been taken.
When the predetermined number N of pictures has been taken, the system exits the loop and the system then calculates the average of the average width of the N pictures (step 118).
Turning now briefly to Figures 2 and 3, it is to be noted that Figure 2 schematically illustrates a typical image captured by the camera 20 when the lumber 24 is made of fir while Figure 3 schematically illustrates a typical image captured by the camera 20 when the lumber 24 is made of spruce. As will be appreciated by one skilled in the art, the average width of the scattered light in the fir lumber is thinner than the average width of the scattered light in the spruce lumber. It is therefore possible to discriminate the species of wood by detecting and calculating the average width of the scattered light.
In step 120, the system determines if the average width is less than a predetermined number. If so, the lumber is determined to be fir (step 122) and this information may be supplied to the conveyor system for further action. If not, the lumber is determined to be spruce (step 124). Again, this information may be supplied to the conveyor system for further action.
Example:
As a non limitative example, a wood differentiating system having the following features has been found appropriate.
Sensor 16: model 42SRP-6002 made by Allen-Bradley Laser 18: model 670-30-20-30 made by Lasiris Vavelength: 670 nm;
optical power: 30 mW;
fan angle: 20°;
working distance: 30 mm Camera 20: model M2SC/HSS1 made by IVP Integrated Vision Products AB; the distance from the camera and the lumber is on the order of 3 to 4 inches.
The computer 12 is provided with a data acquisition card made by IVP under model SC adapter board #10 (7.51 PLD). This card is advantageously able to quickly acquire image data at about 330 Mbits per second. The predetermined number N of pictures to be taken of each lumber has been set to 25. This relatively large number of pictures to be taken of each lumber is advantageous since it significantly decreases the importance of the average width of the scattered light of each picture in the final average of the width for the entire array of pictures, thereby increasing the reliability of the system.
With this setup, it has been found that the cut-off number of pixels to determine if the lumber is made of fir or spruce is 64, 1 p i.e., if the final average width is greater than 64 pixels, the lumber is spruce, if not, it is fir.
Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.
Generally stated, the embodiment of the present invention described hereinbelow has been developed to differentiate between spruce and fir using the principle of light and color scattering in the wood. The wood lumber is illuminated by a line-forming laser and at least one image is captured by a camera. The width of the light scattered along the fibres of the wood is measured and averaged to differentiate between spruce and fir. This information is then used to mechanically separate the spruce and fir lumber for further processing.
Turning now to Figure 1 of the appended drawings, a wood differentiating system 10 according to an embodiment of the present invention will be described.
The wood difFerentiating system 10 includes a computer 12 provided with a monitor 14, a sensor 16, a line-forming laser 18 and a camera 20. The sensor 16, laser 18 and camera 20 are connected to the computer 12.
As can be seen from this figure, the sensor 16, laser 18 and camera 20 are mounted above a conveyor assembly 22 that transversally moves lumbers 24 (see arrows 26).
The sensor 16 is so mounted that it detects a leading edge of a lumber 24 and transfers this data to the computer 12. The laser 18 is so mounted that the line it projects is upon a lumber when the leading edge of this lumber is detected by the sensor 16. The camera 20 is so mounted that it may capture images of the laser line on the lumber when the lumber is detected by the sensor 16.
The'bidirectional link between the camera 20 and the computer 12 is such that the computer may trigger the camera 20 and receive images therefrom for further processing. Similarly, the link between the laser 18 and the computer 12 allows the computer to control the state of the laser. It is to be noted that the link between the laser 18 and the computer 12 is optional. Indeed, the laser 18 could be powered on when the system 10 is energized and powered on a continuous basis without control by the computer.
Turning now to Figure 4 of the appended drawings, illustrating a schematic flow chart of the computer program running in the computer 12, and to Figures 2-3 illustrating images taken by the camera 20, the operation of the wood differentiating system 10 will be described.
The first step is the start of the wood differentiating system 10 (step 100). The system is then initialized in step 102. In step 104, the system waits for the sensor 16 to detect the front edge of a lumber 24.
When a lumber 24 is detected, the system 10 is ready to take a predetermined number N of pictures of the scattered light from the line producing laser 18. In step 106, a counter ("number of pictures") is set to zero (0) before a first image is taken (step 108). The "number of pictures" counter is then incremented in step 110.
The picture is then processed to remove the portion of the image that is directly illuminated by the laser 18 (step 112). This directly illuminated portion is identified by numeral 30 in Figures 2 and 3.
The remaining of the illuminated portion (see numerals 32 and 34 in 5 Figures 2 and 3, respectively) of the lumber is therefore illuminated due to the scattered light along the fibres of the wood.
In step 114, the width of the scattered light on both sides of the laser line is averaged. This width is represented by arrows 36 and 38 in Figures 2 and 3, respectively.
The system then verifies if the "number of pictures"
counter is equal to the predetermined number N of pictures to be taken (step 116). If this is not the case, steps 108-116 are repeated until N
pictures have been taken.
When the predetermined number N of pictures has been taken, the system exits the loop and the system then calculates the average of the average width of the N pictures (step 118).
Turning now briefly to Figures 2 and 3, it is to be noted that Figure 2 schematically illustrates a typical image captured by the camera 20 when the lumber 24 is made of fir while Figure 3 schematically illustrates a typical image captured by the camera 20 when the lumber 24 is made of spruce. As will be appreciated by one skilled in the art, the average width of the scattered light in the fir lumber is thinner than the average width of the scattered light in the spruce lumber. It is therefore possible to discriminate the species of wood by detecting and calculating the average width of the scattered light.
In step 120, the system determines if the average width is less than a predetermined number. If so, the lumber is determined to be fir (step 122) and this information may be supplied to the conveyor system for further action. If not, the lumber is determined to be spruce (step 124). Again, this information may be supplied to the conveyor system for further action.
Example:
As a non limitative example, a wood differentiating system having the following features has been found appropriate.
Sensor 16: model 42SRP-6002 made by Allen-Bradley Laser 18: model 670-30-20-30 made by Lasiris Vavelength: 670 nm;
optical power: 30 mW;
fan angle: 20°;
working distance: 30 mm Camera 20: model M2SC/HSS1 made by IVP Integrated Vision Products AB; the distance from the camera and the lumber is on the order of 3 to 4 inches.
The computer 12 is provided with a data acquisition card made by IVP under model SC adapter board #10 (7.51 PLD). This card is advantageously able to quickly acquire image data at about 330 Mbits per second. The predetermined number N of pictures to be taken of each lumber has been set to 25. This relatively large number of pictures to be taken of each lumber is advantageous since it significantly decreases the importance of the average width of the scattered light of each picture in the final average of the width for the entire array of pictures, thereby increasing the reliability of the system.
With this setup, it has been found that the cut-off number of pixels to determine if the lumber is made of fir or spruce is 64, 1 p i.e., if the final average width is greater than 64 pixels, the lumber is spruce, if not, it is fir.
Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.
Claims (2)
1. A wood differentiating system comprising:
a computer;
a line-forming laser connected to said computer; said line-forming laser being configured and positioned to selectively project a line onto wood lumber;
a camera connected to said computer; said camera being configured and positioned to have said line into its field of view;
wherein said computer determines the width of the scattered light in the wood lumber to differentiate between species.
a computer;
a line-forming laser connected to said computer; said line-forming laser being configured and positioned to selectively project a line onto wood lumber;
a camera connected to said computer; said camera being configured and positioned to have said line into its field of view;
wherein said computer determines the width of the scattered light in the wood lumber to differentiate between species.
2. A wood differentiating method comprising:
projecting a line of laser light onto wood lumber;
capturing an image of said line of laser light;
determining the width of scattered light in said wood lumber;
determining the species of the wood lumber by comparing the width of scattered light with a predetermined width.
projecting a line of laser light onto wood lumber;
capturing an image of said line of laser light;
determining the width of scattered light in said wood lumber;
determining the species of the wood lumber by comparing the width of scattered light with a predetermined width.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2298335 CA2298335A1 (en) | 2000-02-14 | 2000-02-14 | Wood differentiating system |
| CA 2335784 CA2335784A1 (en) | 2000-02-14 | 2001-02-13 | Wood differentiating system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2298335 CA2298335A1 (en) | 2000-02-14 | 2000-02-14 | Wood differentiating system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2298335A1 true CA2298335A1 (en) | 2001-08-14 |
Family
ID=4165289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2298335 Abandoned CA2298335A1 (en) | 2000-02-14 | 2000-02-14 | Wood differentiating system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2298335A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004044566A1 (en) * | 2002-11-14 | 2004-05-27 | Microtec S.R.L. | Device and method for the recording of the surface characteristics of a fibrous structured long object |
-
2000
- 2000-02-14 CA CA 2298335 patent/CA2298335A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004044566A1 (en) * | 2002-11-14 | 2004-05-27 | Microtec S.R.L. | Device and method for the recording of the surface characteristics of a fibrous structured long object |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |