Apparatus for determining the distances of points on a surface from a reference axis

An apparatus for monitoring and determining the distances of points on a surface of a strip of material from a pre-determined reference axis, comprising:

• means for projecting a stationary light beam of small diameter along an optical axis towards the surface;
• means along the axis for dividing the stationary beam into a plurality of angularly spaced apart smaller beams directed towards the surface and extending along a common plane intersecting with the surface to produce a plurality of linearly spaced apart spots of light on the surface;
• first means for gathering reflected light from the points on the surface and projecting real images of the spots onto a straight line along a first photodetector plane;
• and
• first linear photodetector means having a plurality of pre-defined zones positioned along the line extending along the first photodetector plane to receive respective individual images of the spots, the first linear photodetector means providing a quantified signal output representing the positions of the images in respective zones along the line representing the positions on the strip surface where the spots of light occur relative to the reference axis.

An apparatus for monitoring and determining the distances of points on a surface of a strip of material from a predetermined reference axis, comprising:

• means for projecting a stationary light beam of small diameter along an optical axis towards the surface;
• means along the axis for dividing the stationary beam into a plurality of angularly spaced-apart smaller beams directed towards the surface and extending along a common plane intersecting with the surface to produce a plurality of linearly spaced apart spots of light on the surface;
• first means for gathering reflected light from the points on the surface and projecting real images of the spots onto a straight line along a first photodetector plane;
• first linear photodetector means for determining the positions of the real images of the spots along the line extending along the first photodetector plane, the first linear photodetector means including a linear charge coupled image sensor having a plurality of adjacent ones, each said zone being positioned to receive the real image of one of the spots of light, the first linear photodetector means providing a quantified signal output representing the positions of the images along the line representing the positions on the strip surface where the spots of light occur relative to the reference axis.

An optical apparatus comprising:

• light projecting means for projecting a main beam of light of relatively small diameter along an axis;
• beam splitting means positioned along the axis for splitting the beam into a plurality of discrete fractional beams of light;
• means for angularly displacing the fractional beams relative to each other so the beams extend along a common plane towards a position for an object;
• photodetector array means positioned to receive the fractional beams after the fractional beams are reflected off the object, the photodetector array means having a plurality of adjacent zones;
• light gathering means for gathering the fractional beams of light reflected off the object and for projecting the real image of each fractional beam onto a different said zone;
• and
• means for scanning each of the zones sequentially to determine the positions of each of the real images within each of the zones.

An apparatus for monitoring and determining the distances of points on a surface of a strip of material from a pre-determined reference axis, comprising:

• means for projecting a plurality of angularly spaced apart beams of light directed towards the surface and extending along a common plane intersecting with the surface to produce a plurality of linearly spaced apart spots of light on the surface;
• first means for gathering reflected light from the points on the surface and projecting real images of the spots onto a straight line along a first photodetector plane;
• and
• first linear photodetector means having a plurality of pre-defined zones positioned along the line extending along the first photodetector plane to receive respective individual images of the spots, the zones being positioned and dimensioned so that each said image impinges upon a different said zone, whereby the point on the surface corresponding to each beam of light can be determined from the zone upon which each said image impinges, the first linear photodetector means providing a quantified signal output representing the position of each said image in its respective zone along the line representing the position on the strip surface where each said spot of light occurs relative to the reference axis.