Method and apparatus for determining the fiber orientation of paper by measuring the intensity of a light beam at eight or more locations distributed on the circumference of a circle

A method for determining the fiber orientation of paper while on-line, comprising the steps of:

• projecting an unpolarized light beam perpendicularly to a surface of the paper moving in a paper machine;
• measuring the intensity of a light beam reflected by the surface of the paper substantially in the same instant at eight or more locations distributed on a circumference of circle, on the side of the paper upon which the unpolarized light beam is incident, the circle defined in a plane extending in parallel to said surface of the paper and around a point at which an axis of the unpolarized light beam intersects the plane;
• scanning a spot on the surface of the paper being illuminated by the unpolarized light beam transversely of the paper machine;
• and
• calculating fiber orientation characteristics of the paper, including the fiber orientation index value and the fiber orientation angle, from the intensity of reflected light beam measured at each of the eight locations.

An apparatus for determining the fiber orientation of paper, said apparatus comprising:

• a projector for projecting an unpolarized light beam perpendicularly to a surface of paper which is at a standstill or moving;
• eight or more light receivers distributed on the circumference of a circle defined by a plane extending in parallel to the surface of the paper and having a center of a point where an axis of the incident light beam intersects the plane, each light receiver including photoconductive elements adapted to measure the intensity of a light beam reflected by the surface of the paper;
• a light information processor coupled to said receivers and adapted to process a signal representing an intensity of the reflected light beam measured by each of said light receivers and applied to said light information processor to output a light intensity information signal;
• and
• an arithmetic circuit to calculate fiber orientation characteristics such as a fiber orientation index value and a fiber orientation angle from the output signal of said light information processor.

An apparatus for determining the fiber orientation of paper in a paper machine, said apparatus comprising:

• a projector to project an unpolarized light beam perpendicularly to an incident surface of paper moving in the paper machine;
• eight or more light receivers distributed on the incident surface side of the paper and around a circumference of a circle defined in a plane extending in parallel to the incident surface of the paper and having a center point at which an axis of the incident light beam intersects the plane, each of the light receivers including photoconductive elements adapted to measure the intensity of a light beam reflected by the incident surface of the paper;
• a light information processor coupled to said light receivers for processing a signal representing an intensity of the reflected light beam measured by each of the light receivers and applied to the processor to output a light intensity information signal;
• an arithmetic circuit to calculate fiber orientation characteristics such as a fiber orientation index value and a fiber orientation angle from the output signal of the light information processor;
• and
• said projector means and said light receivers scanning the paper transversely of the paper machine.