Language selection

Search

Patent 2514788 Summary

Third-party information liability

Some of the information on this Web page has been provided by external sources. The Government of Canada is not responsible for the accuracy, reliability or currency of the information supplied by external sources. Users wishing to rely upon this information should consult directly with the source of the information. Content provided by external sources is not subject to official languages, privacy and accessibility requirements.

Claims and Abstract availability

Any discrepancies in the text and image of the Claims and Abstract are due to differing posting times. Text of the Claims and Abstract are posted:

  • At the time the application is open to public inspection;
  • At the time of issue of the patent (grant).
(12) Patent Application: (11) CA 2514788
(54) English Title: SYSTEM AND METHOD FOR THE DETECTION OF BLUESTAIN AND ROT ON WOOD
(54) French Title: SYSTEME ET METHODE DE DETECTION DU BLEUISSEMENT ET DE LA POURRITURE SUR LE BOIS
Status: Deemed Abandoned and Beyond the Period of Reinstatement - Pending Response to Notice of Disregarded Communication
Bibliographic Data
(51) International Patent Classification (IPC):
  • G01N 21/47 (2006.01)
  • G01N 21/89 (2006.01)
  • G01N 33/46 (2006.01)
(72) Inventors :
  • LAURENT, JOHN (Canada)
  • TALBOT, MARIO (Canada)
  • ETHIER, DANIEL (Canada)
(73) Owners :
  • INSTITUT NATIONAL D'OPTIQUE
  • AUTOLOG INC.
(71) Applicants :
  • INSTITUT NATIONAL D'OPTIQUE (Canada)
  • AUTOLOG INC. (Canada)
(74) Agent: ROBIC AGENCE PI S.E.C./ROBIC IP AGENCY LP
(74) Associate agent:
(45) Issued:
(22) Filed Date: 2005-08-08
(41) Open to Public Inspection: 2006-02-06
Availability of licence: N/A
Dedicated to the Public: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): No

(30) Application Priority Data:
Application No. Country/Territory Date
2,478,737 (Canada) 2004-08-06

Abstracts

English Abstract


A system for detecting bluestain and rot in wood in a wood processing plant
including a conveyor for conveying a piece of wood through a scanning area
includes a scanning unit comprising a plurality of scanners arranged to scan a
face
of the piece of wood in a direction perpendicular to a conveying direction.
Each of
the scanners include a light for illuminating a point on the piece of wood; a
collector for collecting light reflected from the piece of wood; a splitter
for splitting
the collected light into at least two beams; a filter for filtering out of
each of the
beams a wavelength associated with each of the beams, each of the wavelengths
being different; a collector for collecting the filtered light, the collector
being
adapted to output a signal related to an intensity of the filtered light; and
a
comparator for comparing the output of each of the collector, the comparator
being
adapted to output a signal when a ratio between the signal between each of the
collector exceeds a predetermined threshold.


Claims

Note: Claims are shown in the official language in which they were submitted.


8
CLAIMS
1. A system for detecting bluestain and rot in wood in a wood processing
plant, said wood processing plant including a conveyor for conveying a piece
of
wood through a scanning area, said system comprising:
a scanning unit comprising a plurality of scanners arranged to scan a face
of said piece of wood in a direction perpendicular to a conveying direction of
said
piece of wood, each of said scanners comprising:
a light for illuminating a point on said piece of wood;
a collector for collecting light reflected from said piece of wood;
a splitter for splitting said collected light into at least two beams;
a filter for filtering out of each of said beams a wavelength associated
with each of said beams, each of the wavelengths being different;
a collector for collecting the filtered light, said collector being adapted
to output a signal related to an intensity of said filtered light; and
a comparator for comparing the output of each of the collector, said
comparator being adapted to output a signal when a ratio between said signal
between each of said collector exceeds a predetermined threshold.
2. A system according to claim 1, wherein said light is adapted to shine a
point
on said piece of wood that is stable in intensity over a depth of 3 inches.
3. A system according to claim 1, wherein said light is in the range of 900-
1200 nm.
4. A system according to claim 1, wherein said system includes 12 scanners,
aligned with each other in a direction perpendicular to said conveying
direction of
said piece of wood, each of the scanners being separated by an inch.
5. A system according to claim 4, wherein said system is comprised of 12
individual scanners.

9
6. A system according to claim 4, wherein said system is comprised of 12
scanners monolithically assembled in one piece.
7. A system according to claim 1, wherein said system is further operatively
connected to a data collector which synchronizes said output of said
comparator
with the passage of said wood piece through said scanning area in order to
scan
said wood piece at a predetermined interval.
8. A system according to claim 7, wherein said interval is between 0.125 and
0.500 inches.
9. A system for grading a piece of wood based on the detection of bluestain
and rot, said system comprising:
a first scanning unit according to claim 1 for scanning a top of said piece of
wood;
a second scanning unit according to claim 1 for scanning a bottom of said
piece of wood;
a data collector which synchronizes said output of said comparator with the
passage of said wood piece through said scanning area in order to scan said
wood piece at a predetermined interval, for collecting said output of each of
said
comparator; and
a grading computer for grading said piece of wood according to data
collected by said data collector.
10. A system according to claim 9, wherein said system further includes:
a third scanning unit according to claim 1, said third scanning unit being
located adjacent said first scanning unit, and offset from said first scanning
unit;
and
a fourth scanning unit according to claim 1, said fourth scanning unit being
located adjacent said second scanning unit, and offset from said second
scanning
unit.

10
11. A method for detecting bluestain and rot in wood comprising the steps of:
(a) providing a scanning unit comprising a plurality of scanners
arranged to scan a face of said piece of wood in a direction
perpendicular to a conveying direction of said piece of wood;
(b) with said scanning unit:
(i) illuminating a point on said piece of wood;
(ii) collecting light reflected from said piece of wood;
(iii) splitting said collected light into at least two beams;
(iv) filtering out of each of said beams a wavelength
associated with each of said beams, each of the
wavelengths being different;
(v) collecting the filtered light with a collector adapted to
output a signal related to an intensity of said filtered
light;
(vi) comparing the output of each of the collector; and
(vii) outputting a signal when a ratio between said signal
between each of said collector exceeds a
predetermined threshold.

Description

Note: Descriptions are shown in the official language in which they were submitted.


CA 02514788 2005-08-08
1
SYSTEM AND METHOD FOR THE DETECTION
OF BLUESTAIN AND ROT ON WOOD
FIELD OF THE INVENTION
The present invention relates to a system and method for the detection of
bluestain and rot on wood. More specifically, the present invention concerns
such
a system and method where the detection is made by spectrally analysing tight
reflected off the wood.
DESCRIPTION OF THE PRIOR ART
The quantity of wood that is stained with bluestain is constantly increasing,
particularly since the forests of British Columbia have been infested with an
insect
known as mountain pine beetle. This type of wood is easily distinguished from
other woods by its blue colour, due to the fungi carried by the insect. The
volume
of bluestain wood treated by mills increases, but consumers are reluctant to
use
this wood, even though studies have demonstrated that the physical properties
of
the wood are unaffected. Mill operators would like to the able to grade
bluestain
wood during the early stages of classification, either at the planing step or
at the
cutting step. The colour of bluestain wood, varying from grey to black, is
also akin
to that of rot. Hence, a sensor for detecting bluestain must detect not only
bluestain but also rot, without being affected by the other natural defects of
the
wood.
There is not presently technology available in sawmills (and particularly
those of
first transformation) which permits the detection of bluestain. There are
scanners
that exist, but they are used in mills of secondary transformation. Most of
the

CA 02514788 2005-08-08
2
scanners are based on 2D colour cameras, the image of which is then analysed
by
a computer program. The problem is that the colour of the bluestain is
difficult to
determine with any certainty from a colour image, and is easily mistaken for
other
defects. Furthermore, the computer programs are based on complicated
algorithms which compare regions of the image in order to make a
determination,
which makes the processing of the image heavy and difficult to implement in
real
time. The detection level being low, human intervention is generally required
to
make a final classification of the wood.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system and method for
detecting bluestain and rot on a piece of wood which is based on a spectral
analysis of the piece of wood.
In accordance with one aspect of the invention, there is provided a system for
detecting bluestain and rot in wood in a wood processing plant, said wood
processing plant including a conveyor for conveying a piece of wood through a
scanning area, said system comprising:
a scanning unit comprising a plurality of scanners arranged to scan a face
of said piece of wood in a direction perpendicular to a conveying direction of
said
piece of wood, each of said scanners comprising:
a light for illuminating a point on said piece of wood;
a collector for collecting light reflected from said piece of wood;
a splitter for splitting said collected light into at least two beams;
a filter for filtering out of each of said beams a wavelength associated
with each of said beams, each of the wavelengths being different;
a collector for collecting the filtered light, said collector being adapted
to output a signal related to an intensity of said filtered light; and

CA 02514788 2005-08-08
3
a comparator for comparing the output of each of the collector, said
comparator being adapted to output a signal when a ratio between said signal
between each of said collector exceeds a predetermined threshold.
In accordance with another aspect of the invention, there is provided a system
for
grading a piece of wood based on the detection of bluestain and rot, said
system
comprising:
a first scanning unit according to claim 1 for scanning a top of said piece of
wood;
a second scanning unit according to claim 1 for scanning a bottom of said
piece of wood;
a data collector which synchronizes said output of said comparator with the
passage of said wood piece through said scanning area in order to scan said
wood piece at a predetermined interval, for collecting said output of each of
said
comparator; and
a grading computer for grading said piece of wood according to data
collected by said data collector.
In accordance with yet another aspect of the invention, there is provided a
method
for detecting bluestain and rot in wood comprising the steps of:
(a) providing a scanning unit comprising a plurality of
scanners arranged to scan a face of said piece of wood
in a direction perpendicular to a conveying direction of
said piece of wood;
(b) with said scanning unit:
(i) illuminating a point on said piece of wood;
(ii) collecting light reflected from said piece of wood;
(iii) splitting said collected light into at least two
beams;

CA 02514788 2005-08-08
4
(iv) filtering out of each of said beams a wavelength
associated with each of said beams, each of the
wavelengths being different;
(v) collecting the filtered light with a collector
adapted to output a signal related to an intensity
of said ~Itered light;
(vi) comparing the output of each of the collector;
and
(vii) outputting a signal when a ratio between said
signal between each of said collector exceeds a
predetermined threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detailed in the following description
of a
preferred embodiment of the invention, made with reference to the following
drawings in which:
Figure 1 is schematic representation of a system for grading a piece of wood
conveyed in a longitudinal direction, consisting of two scanning units, a data
collector and a grading computer;
Figure 2 is cross-sectional view of Figure 1 showing only the top scanning
unit;
Figure 3 is a schematic representation of the arrangement of the light, the
lens and
the filters and detectors;
Figure 4 is a bottom view of a scanning unit;
Figure 5 is a detailed view of the scanner, showing details different from
those of
Fig. 3; and

CA 02514788 2005-08-08
Figure 6 is a schematic view of two scanning units for each surface of the
piece of
wood, offset from each other.
5 DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
As mentioned previously, the present invention is based on a spectral analysis
of
the piece of wood. This provides the advantage that the detection does not
depend on the interpretation of an image, as in the scanners of the prior art,
but
rather depends on the reaction of the wood to certain specific wavelengths of
light
reflected off the piece of wood.
More specifically, the present invention concerns a system for detecting
bluestain
and rot in wood in a wood processing plant, the wood processing plant
including a
conveyor 10 for conveying a piece of wood through a scanning area 12.
The system includes a scanning unit 20 comprising a plurality of scanners 22
arranged to scan a face of the piece of wood in a direction perpendicular to a
conveying direction of said piece of wood. The scanning unit can be
monolithical,
in that it is made of a single piece, or could be made of a plurality of
individual
scanners mounted together. In Fig. 1, the scanners are individual.
Referring now to Figs. 2, 3 and 5, each of the scanners includes a light 23
for
illuminating a point on said piece of wood. There is also provided a collector
25 for
collecting light reflected from the piece of wood; a splitter 27 for splitting
the
collected light into at least two beams 29, 31; and a filter 33, 34 for
filtering out of
each of the beams 29, 31 a wavelength associated with each of the beams, each
of the wavelengths being different. The scanners further include a collector
35, 36
for collecting the filtered light, the collector being adapted to output a
signal related
to an intensity of said filtered light; and a comparator 37 for comparing the
output
of each of the collector, the comparator being adapted to output a signal when
a

CA 02514788 2005-08-08
6
ratio between the signal between each of said collector exceeds a
predetermined
threshold.
As better shown in Figs. 3 and 5, the light 23 is preferably LEDs. More
preferably,
the LEDs are arranged in a line (which is parallel to the conveying direction
of the
piece of wood). In order to provide better results, the LEDs are further
disposed on
either side of the collector 25, which is in a preferred embodiment a lens.
Further
preferably, the LEDs are selected to emit light in the spectrum of 900 to 1200
nm.
Given the fact that pieces of wood have varying thicknesses, the LEDs are
adapted to illuminate the piece of wood with a stable intensity for a depth of
3
inches (see Fig. 2). Thus, the scanning unit 22 is preferably placing 6 inches
away
from the conveyor 10.
As shown in Fig. 3, the splitter 27 and filter 34 are a single component, as a
person skilled in the art of optics would readily understand. The detectors
35, 36,
as shown in Fig. 5, are preferably mounted on PCBs, which further include the
electronic components required to output the signal related to the intensity
of light.
Such detectors are well known, and are readily available.
The comparator 27 is also a well known component, and details of its
construction
are not included herein. However, the output of the comparator is preferably
an
analog signal, varying for example between 0-10 V, indicative of the strength
of
the signals received by the collectors.
As mentioned previously, the present invention is based on a spectral analysis
of
the light reflected from the piece of wood. It has been found that although a
single
wavelength may be used for the purpose of detecting bluestain and rot, the
efficiency and accuracy of the system is further increased by comparing a
ratio
between the intensity of at least two wavelengths. It should be noted that the
ration
can compare three or more wavelengths, but accuracy does not necessarily
increase.

CA 02514788 2005-08-08
7
The inventors have found that the best results occur in the range of 900-1200
nm.
Two combinations of wavelengths have been found to be the best: the ratio of
985
nm over 965 nm (or 980 nm over 960 nm) and 1140 nm over 955 nm. The choice
will most likely depend on the impact of false detections caused by knots. If
a false
detection would have no impact, then the first pair of wavelengths should be
selected; otherwise the second should be considered.
In order to provide optimal scanning, the wood is conveyed longitudinally, and
the
scanning unit is provided with twelve scanners, separated from each other by a
distance of one inch (see Fig. 4). Of course, if the piece of wood is scanned
transversely, then the scanning unit should have enough scanners to scan the
whole length of the piece of wood.
The system of the present invention is further preferably connected to a data
collector which is operatively associated with the conveyor. This enables the
data
collector to synchronize the collection of data as the piece of wood passes
through
the scanning area 12. Preferably, the piece of wood is scanned at every 0.125
to
every 0.500 inch, depending on the accuracy required.
As is typical in sawmills, there are also grading computers, which permit the
grading of a piece of wood according to a variety of surface defects, etc. The
data
collector can then be integrated into a grading system.
In order to provide even greater accuracy, as shown in Fig. 6, two scanning
units
can be placed over each surface of the piece of wood. In such a case, the
scanning units on one side a offset by approximately'/2 inch.
Although the present invention has been explained hereinabove by way of a
preferred embodiment thereof, it should be pointed out that any modifications
to
this preferred embodiment within the scope of the appended claims is not
deemed
to alter or change the nature and scope of the present invention.

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

2024-08-01:As part of the Next Generation Patents (NGP) transition, the Canadian Patents Database (CPD) now contains a more detailed Event History, which replicates the Event Log of our new back-office solution.

Please note that "Inactive:" events refers to events no longer in use in our new back-office solution.

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Event History , Maintenance Fee  and Payment History  should be consulted.

Event History

Description Date
Application Not Reinstated by Deadline 2010-08-09
Time Limit for Reversal Expired 2010-08-09
Deemed Abandoned - Failure to Respond to Maintenance Fee Notice 2009-08-10
Application Published (Open to Public Inspection) 2006-02-06
Inactive: Cover page published 2006-02-06
Inactive: IPC assigned 2006-02-03
Inactive: IPC assigned 2006-02-03
Inactive: IPC assigned 2006-02-03
Inactive: First IPC assigned 2006-02-03
Letter Sent 2006-01-11
Letter Sent 2006-01-11
Inactive: Applicant deleted 2006-01-10
Inactive: Single transfer 2005-11-23
Inactive: Correspondence - Formalities 2005-11-23
Inactive: Correspondence - Formalities 2005-11-15
Inactive: Compliance - Formalities: Resp. Rec'd 2005-11-15
Inactive: Filing certificate - No RFE (English) 2005-09-20
Application Received - Regular National 2005-09-20

Abandonment History

Abandonment Date Reason Reinstatement Date
2009-08-10

Maintenance Fee

The last payment was received on 2008-06-09

Note : If the full payment has not been received on or before the date indicated, a further fee may be required which may be one of the following

  • the reinstatement fee;
  • the late payment fee; or
  • additional fee to reverse deemed expiry.

Patent fees are adjusted on the 1st of January every year. The amounts above are the current amounts if received by December 31 of the current year.
Please refer to the CIPO Patent Fees web page to see all current fee amounts.

Fee History

Fee Type Anniversary Year Due Date Paid Date
Application fee - standard 2005-08-08
2005-11-15
Registration of a document 2005-11-23
MF (application, 2nd anniv.) - standard 02 2007-08-08 2007-07-26
MF (application, 3rd anniv.) - standard 03 2008-08-08 2008-06-09
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
INSTITUT NATIONAL D'OPTIQUE
AUTOLOG INC.
Past Owners on Record
DANIEL ETHIER
JOHN LAURENT
MARIO TALBOT
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
Documents

To view selected files, please enter reCAPTCHA code :



To view images, click a link in the Document Description column. To download the documents, select one or more checkboxes in the first column and then click the "Download Selected in PDF format (Zip Archive)" or the "Download Selected as Single PDF" button.

List of published and non-published patent-specific documents on the CPD .

If you have any difficulty accessing content, you can call the Client Service Centre at 1-866-997-1936 or send them an e-mail at CIPO Client Service Centre.


Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Description 2005-08-07 7 284
Abstract 2005-08-07 1 26
Drawings 2005-08-07 3 49
Claims 2005-08-07 3 99
Drawings 2005-11-14 4 48
Representative drawing 2006-01-10 1 15
Filing Certificate (English) 2005-09-19 1 157
Courtesy - Certificate of registration (related document(s)) 2006-01-10 1 104
Courtesy - Certificate of registration (related document(s)) 2006-01-10 1 104
Reminder of maintenance fee due 2007-04-10 1 109
Courtesy - Abandonment Letter (Maintenance Fee) 2009-10-04 1 172
Reminder - Request for Examination 2010-04-11 1 121
Correspondence 2005-09-19 1 25
Correspondence 2005-11-14 5 74
Correspondence 2005-11-22 4 105
Fees 2007-07-25 1 40
Fees 2008-06-08 1 43