OPTICAL INSPECTION APPARATUS AND METHOD

• US 20120274758A1
• Filed: 07/15/2011
• Published: 11/01/2012
• Est. Priority Date: 04/28/2011
• Status: Active Grant

• Current Assignee: Centre de recherche industrielle du Québec
• Original Assignee: Centre de recherche industrielle du Québec
• Inventors: Lessard, Denis
• Granted Patent: US 8,723,945 B2
• Time in Patent Office: Days
• US Class Current: 348/92
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence

Abstract

An optical apparatus and method for simultaneously scanning the profile of at least two adjacent surfaces of an article such as a wooden board moving along a travel path axis passing through an inspection area located at a central plane transverse to the travel path axis, involve first and second scanning zones sufficiently spaced one with another along the travel path axis to substantially prevent mutual scanning interference between the profile sensors used, while providing a compact arrangement of profile sensors. For so doing, one the first sensing field and the first laser beam of the first profile sensor is crossing the central plane toward the other one of the first sensing field and the first laser beam, and one the second sensing field and the second laser beam of the second profile sensor is crossing the central plane toward the other one of the second sensing field and the second laser beam.

Claims

1. An optical inspection apparatus for simultaneously scanning the profile of at least two adjacent surfaces of an article moving along a travel path axis passing through an inspection area located at a central plane transverse to said travel path axis, the apparatus comprising:

a first profile sensor unit having a first optical sensing field directed toward said travel path axis and defining a first scanning zone associated with a first one of said adjacent surfaces as intersected by said first sensing field, and a first laser source directing at angle with said first sensing field a first fan-shaped laser beam toward the first scanning zone to define an associated first scanning plane transverse to said travel path axis, to generate first sensor output data related to the profile of said first article surface; and

a second profile sensor unit having a second optical sensing field directed toward said travel path axis and defining a second scanning zone associated with a second one of said adjacent surfaces as intersected by said second sensing field, and a second laser source directing at angle with said second sensing field a second fan-shaped laser beam toward the second scanning zone to define an associated second scanning plane transverse to said travel path axis, to generate second sensor output data related to the profile of said second article surface;

wherein the first and second profile sensor units are disposed one with respect to another so that;

their respective first and second scanning zones are sufficiently spaced one with another along said travel path axis to substantially prevent mutual scanning interference between said first and second profile sensor units; and

one of said first sensing field and said first laser beam is crossing the central plane toward the other one of said first sensing field and said first laser beam, one of said second sensing field and said second laser beam is crossing the central plane toward the other one of said second sensing field and said second laser beam, to provide a compact arrangement of said first and second profile sensor units.

2. The optical inspection apparatus according to claim 1, wherein said first laser beam is directed toward the first scanning zone within said first scanning plane, said second laser beam is directed toward the second scanning zone within said second scanning plane, said first sensing field is crossing the central plane toward said first laser beam, said second sensing field is crossing the central plane toward said second laser beam.

3. The optical inspection apparatus according to claim 1, wherein said first sensing field is directed toward said travel path axis within said first scanning plane, said second sensing field is directed toward said travel path axis within said second scanning plane, said first laser beam is crossing the central plane toward said first sensing field, said second laser beam is crossing the central plane toward said second sensing field.

4. The optical inspection apparatus according to claim 1, wherein said first surface is a main surface associated with a first dimension transverse to said travel path axis and of a value selected from a first range of dimension values, said second surface is a side surface associated with a second dimension transverse to said travel path axis and of a value selected from a second range of dimension values, said first optical sensing field having a depth adapted to define said first scanning zone for any selected value of said second dimension, said second optical sensing field having a depth adapted to define said second scanning zone for any selected value of said first dimension.

5. The optical inspection apparatus according to claim 1, wherein said first profile sensor unit includes:

a first digital camera defining said first sensing field and capturing a two-dimensional image of a first reflected laser line formed by said first laser beam onto said first surface to generate corresponding first two-dimensional image data; and

first data processing means for deriving said profile-related output data from said first two-dimensional image data;

and wherein said second profile sensor unit includes;

a second digital camera defining said second sensing field and capturing a two-dimensional image of a second reflected laser line formed by said second laser beam onto said second surface to generate corresponding second two-dimensional image data; and

second data processing means for deriving said profile-related output data from said second two-dimensional image data.

6. An optical inspection apparatus for simultaneously scanning the profile of an article having a top surface and a first side surface adjacent thereto, a bottom surface and a second side surface adjacent thereto, said article moving along a travel path axis passing through an inspection area located at a central plane transverse to said travel path axis, the apparatus comprising:

a first profile sensor unit having a first optical sensing field directed toward said travel path axis and defining a first scanning zone associated with said top surface as intersected by said first sensing field, and a first laser source directing at angle with said first sensing field a first fan-shaped laser beam toward the first scanning zone to define an associated first scanning plane transverse to said travel path axis, to generate first sensor output data related to the profile of said top article surface;

a second profile sensor unit having a second optical sensing field directed toward said travel path axis and defining a second scanning zone associated with said first side surface as intersected by said second sensing field, and a second laser source directing at angle with said second sensing field a second fan-shaped laser beam toward the second scanning zone to define an associated second scanning plane transverse to said travel path axis, to generate second sensor output data related to the profile of said first side article surface;

wherein the first and second profile sensor units are disposed one with respect to another so that;

their respective first and second scanning zones are sufficiently spaced one with another along said travel path axis to substantially prevent mutual scanning interference between said first and second profile sensor units; and

one of said first sensing field and said first laser beam is crossing the central plane toward the other one of said first sensing field and said first laser beam, one of said second sensing field and said second laser beam is crossing the central plane toward the other one of said second sensing field and said second laser beam, to provide a compact arrangement of said first and second profile sensor units;

a third profile sensor unit having a third optical sensing field directed toward said travel path axis and defining a third scanning zone associated with said bottom surface as intersected by said third sensing field, and a third laser source directing at angle with said third sensing field a third fan-shaped laser beam toward the third scanning zone to define an associated third scanning plane transverse to said travel path axis, to generate third sensor output data related the profile of said bottom article surface;

a fourth profile sensor unit having a fourth optical sensing field directed toward said travel path axis and defining a fourth scanning zone associated with said second side surface as intersected by said fourth sensing field, and a fourth laser source directing at angle with said fourth sensing field a fourth fan-shaped laser beam toward the fourth scanning zone to define a fourth associated scanning plane transverse to said travel path axis, to generate fourth sensor output data related the profile of said second side article surface;

wherein the second and fourth profile sensor units are disposed one with respect to another so that;

their respective third and fourth scanning zones are sufficiently spaced one with another along said travel path axis to substantially prevent mutual scanning interference between said third and fourth profile sensor units; and

one of said third sensing field and said third laser beam is crossing the central plane toward the other one of said third sensing field and said third laser beam, one of said fourth sensing field and said fourth laser beam is crossing the central plane toward the other one of said fourth sensing field and said fourth laser beam, to provide a compact arrangement of said third and fourth profile sensor units.

7. The apparatus according to claim 6, wherein said first and third scanning planes are substantially coplanar, said second and fourth scanning planes are substantially coplanar.

8. The inspection apparatus according to claim 6, wherein:

said first laser beam is directed toward the first scanning zone within said first scanning plane, said second laser beam is directed toward the second scanning zone within said second scanning plane, said first sensing field is crossing the central plane toward said first laser beam, said second sensing field is crossing the central plane toward said second laser beam;

said third laser beam is directed toward the third scanning zone within said third scanning plane, said fourth laser beam is directed toward the fourth scanning zone within said fourth scanning plane, said third sensing field is crossing the central plane toward said third laser beam, said fourth sensing field is crossing the central plane toward said fourth laser beam.

9. The inspection apparatus according to claim 6, wherein:

said first sensing field is directed toward said travel path axis within said first scanning plane, said second sensing field is directed toward said travel path axis within said second scanning plane, said first laser beam is crossing the central plane toward said first sensing field, said second laser beam is crossing the central plane toward said second sensing field;

said third sensing field is directed toward said travel path axis within said third scanning plane, said fourth sensing field is directed toward said travel path axis within said fourth scanning plane, said third laser beam is crossing the central plane toward said third sensing field, said fourth laser beam is crossing the central plane toward said fourth sensing field.

10. The inspection apparatus according to claim 6, wherein:

said first profile sensor unit includes;

a first digital camera defining said first sensing field and capturing a two-dimensional image of a first reflected laser line formed by said first laser beam onto said top surface to generate corresponding first two-dimensional image data; and

first data processing means for deriving said profile-related output data from said first two-dimensional image data;

said second profile sensor unit includes;

a second digital camera defining said second sensing field and capturing a two-dimensional image of a second reflected laser line formed by said second laser beam onto said first side surface to generate corresponding second two-dimensional image data; and

second data processing means for deriving said profile-related output data from said second two-dimensional image data;

said third profile sensor unit includes;

a third digital camera defining said third sensing field and capturing a two-dimensional image of a third reflected laser line formed by said third laser beam onto said bottom surface to generate corresponding third two-dimensional image data; and

third data processing means for deriving said profile-related output data from said third two-dimensional image data;

said fourth profile sensor unit includes;

a fourth digital camera defining said fourth sensing field and capturing a two-dimensional image of a fourth reflected laser line formed by said fourth laser beam onto said second side surface to generate corresponding fourth first two-dimensional image data; and

fourth data processing means for deriving said profile-related output data from said fourth two-dimensional image data.

11. An optical method for simultaneously scanning the profile of at least two adjacent surfaces of an article moving along a travel path axis passing through an inspection area located at a central plane transverse to said travel path axis, the method comprising the steps of:

directing a first optical sensing field of a first profile sensor toward said travel path axis, said first sensing field defining a first scanning zone associated with a first one of said adjacent surfaces as intersected by said first sensing field;

directing at angle with said first sensing field a first fan-shaped laser beam toward the first scanning zone to define an associated first scanning plane transverse to said travel path axis, causing said first profile sensor to generate first sensing output data related the profile of said first article surface;

directing a second optical sensing field of a second sensor toward said travel path axis, said second sensing filed defining a second scanning zone associated with a second one of said adjacent surfaces as intersected by said second sensing field;

directing at angle with said second sensing field a second fan-shaped laser beam toward the second scanning zone to define an associated second scanning plane transverse to said travel path axis, causing said second profile sensor to generate second sensor output data related the profile of said second article surface;

wherein the first and second scanning zones are sufficiently spaced one with another along said travel path axis to substantially prevent mutual scanning interference between said first and second profile sensors; and

one of said first sensing field and said first laser beam is crossing the central plane toward the other one of said first sensing field and said first laser beam, one of said second sensing field and said second laser beam is crossing the central plane toward the other one of said second sensing field and said second laser beam, to provide a compact arrangement of said first and second profile sensors.

12. The optical scanning method according to claim 11, wherein said first laser beam is directed toward the first scanning zone within said first scanning plane, said second laser beam is directed toward the second scanning zone within said second scanning plane, said first sensing field is crossing the central plane toward said first laser beam, said second sensing field is crossing the central plane toward said second laser beam.

13. The optical scanning method according to claim 11, wherein said first sensing field is directed toward said travel path axis within said first scanning plane, said second sensing field is directed toward said travel path axis within said second scanning plane, said first laser beam is crossing the central plane toward said first sensing field, said second laser beam is crossing the central plane toward said second sensing field.

14. The optical scanning method according to claim 11, wherein said first surface is a main surface associated with a first dimension transverse to said travel path axis and of a value selected from a first range of dimension values, said second surface is a side surface associated with a second dimension transverse to said travel path axis and of a value selected from a second range of dimension values, said first optical sensing field having a depth adapted to define said first scanning zone for any selected value of said second dimension, said second optical sensing field having a depth adapted to define said second scanning zone for any selected value of said first dimension.