Apparatus and method for detecting surface defects

An apparatus for detecting missing wood on at least one surface of a wooden article having at least one pair of opposed surfaces, said article being conveyed in a scanning direction, the apparatus comprising:

• surface shape inspection means for obtaining profile data of said at least one pair of opposed surfaces at a cross-section, said profile data being referenced to a reference system;
• data processing means for deriving at least a pair of base reference curves through a curve fitting algorithm applied to generally regular portions of said profile data;
• and
• missing wood detecting means for measuring spacing between said pair of base reference curves to recognize a defect induced spacing departure from a predetermined minimum spacing to produce a defect output signal.

An apparatus for detecting longitudinal surface defects on an article being conveyed in a scanning direction, the apparatus comprising:

• surface shape inspection means for obtaining profile data of at least one surface of said article at successive cross-sections, said profile data being referenced to a reference system;
• data processing means for deriving a plurality of successive base reference curves from generally regular portions of said profile data;
• and
• defect detecting means comparing adjacent ones of said base reference curves to recognize position shifts for corresponding adjacent ones of said cross-sections and to produce a defect output signal indicative of a surface defect extending along said surface whenever values of said position shifts are higher than a predetermined defect threshold value.

An apparatus for detecting surface defects on an article, the apparatus comprising:

• surface shape inspection means for obtaining profile data of at least one surface at successive cross-sections, said profile data being referenced to a reference system, said surface shape inspection means being displaceable with respect to said at least one surface in a scanning direction;
• data processing means for deriving successive base reference curves through a curve fitting algorithm applied to generally regular portions of said profile data;
• and
• defect detecting means comparing said profile data with said successive base reference curves to recognize a defect induced departure of said data with respect to said base reference curves and to produce a defect output signal.

A method for detecting surface defects on an article the method comprising steps of:

• i) obtaining profile data of at least one surface of said article at a cross-section, said profile data being reference to a reference system;
• ii) deriving a base reference curve through a curve fitting algorithm applied to generally regular portions of said profile data:
• iii) comparing said profile data with said base reference curve to recognize a defect induced departure of said profile data with respect to said base reference curve;
• and
• iv) producing a defect output signal.

A method for detecting missing wood on at least one surface of a wooden article having at least one pair of opposed surfaces, comprising steps of:

• i) generating profile data of said at least one pair of opposed surfaces at a cross-section, said profile data being referenced to a reference system;
• ii) deriving at least a pair of base reference curves through a curve fitting algorithm applied to generally regular portions of said profile data;
• iii) measuring spacing between said pair of base reference curves to recognize a defect induced spacing departure from a predetermined minimum spacing;
• and
• iv) producing a defect output signal.

A method for detecting longitudinal surface defects on an article comprising steps of:

• i) generating profile data of at least one surface of said article at successive cross-sections, said profile data being referenced to a reference system;
• ii) deriving a plurality of successive base reference curves from generally regular portions of said profile data;
• iii) comparing adjacent ones of said base reference curves to recognize position shifts for corresponding adjacent ones of said cross-sections;
• iv) producing a defect output signal indicative of a surface defect extending along said surface whenever values of said position shifts are higher than a predetermined defect threshold value.