Confocal measurement method and apparatus in a paper machine

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• focusing the collected light onto a plurality of targets;
• measuring an amount of light focused on said plurality of targets using at least one light detector;
• generating output signals from said at least one light detector;
• establishing an exact position of a focal point of said focused light;
• and
• determining the distance to the object using said exact position of the focal point.

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• focusing the collected light toward at least one target;
• establishing an exact position of a focal point of said focused light;
• and
• determining the distance to the object using said exact position of said focal point.

In a paper machine, an apparatus for determining a distance to a fiber web, comprising:

• a light source;
• a lens for focusing light from said light source onto the fiber web, and collecting light that is reflected and scattered from the fiber web;
• at least one splitter for splitting the collected light into at least two beams;
• a plurality of targets, each said target having a respective said split beam focused thereon, each said target being at a different fixed location relative to a focal point of said focused split beams;
• and
• an electrical processing circuit for establishing an exact position of a focal point of said split light, and determining a distance to the object using said exact position of said focal point.

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• splitting the collected light into at least two beams;
• focusing each said split beam toward a respective pinhole, each said pinhole being at a different fixed location relative to a focal point of said focused split beams;
• positioning at least one light detector behind each said pinhole;
• and
• determining the distance to the object using output signals from each said light detector.

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• focusing the collected light toward an array of light detectors;
• and
• determining the distance to the object using output signals from each said light detector.

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• splitting the collected light into at least two beams;
• focusing each said split beam toward a respective array of light detectors, each said array of light detectors being at a different fixed location relative to a focal point of said focused split beams;
• and
• determining the distance to the object using output signals from each said light detector.

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• focusing the collected light toward a bundle of fibers ends in a fiber optic cable;
• guiding light focused on a center area of said fiber ends to one light detector and guiding light focused on other areas of said fiber ends to a plurality of other light detectors;
• establishing an exact position of a focal point of said focused light using output signals from said light detectors;
• and
• determining the distance to the object using said exact position of said focal point.

A method of determining a distance to an object, comprising the steps of:

• focusing light from a light source onto the object using a lens;
• collecting light that is reflected and scattered from the object using said lens;
• splitting the collected light into at least two beams;
• focusing each said split beam toward a respective fiber optic cable end, each said fiber optic cable end having a bundle of fibers ends, each said fiber optic cable end being at a different fixed location relative to a focal point of said focused split beams;
• guiding light focused on a center area of said fiber ends of each said fiber optic cable end to one light detector and guiding light focused on other areas of said fiber ends of each said fiber optic cable end to a plurality of other light detectors;
• establishing an exact position of a focal point of said focused split beams using output signals from each of said light detectors;
• and
• determining the distance to the object using said exact position of said focal point.

On a paper machine, a method of determining a distance to a moving web, comprising the steps of:

• focusing light from a light source onto the web using a lens;
• collecting light that is reflected and scattered from the web using said lens;
• splitting the collected light into at least two beams;
• focusing each said split beam toward a respective pinhole, each said pinhole being at a different fixed location relative to a focal point of said focused split beams;
• positioning at least one light detector behind each said pinhole;
• and
• determining the distance to the web using output signals from each said light detector.

On a paper machine, a method of determining a distance to a moving web, comprising the steps of:

• focusing light from a light source onto the web using a lens;
• collecting light that is reflected and scattered from the web using said lens;
• splitting the collected light into at least two beams;
• focusing each said split beam toward a respective fiber optic cable end, each said fiber optic cable end being at a different fixed location relative to a focal point of said focused split beams;
• guiding light focused on fiber ends of each said fiber optic cable end to at least one light detector;
• and
• determining the distance to the web using output signals from each said light detector.

On a paper machine, a method of determining a distance to a moving web, comprising the steps of:

• focusing the light from a light source onto the web using a lens;
• collecting light that is reflected and scattered from the web using said lens;
• splitting the collected light into at least two beams;
• focusing each said split beam toward a respective array of light detectors, each said array of light detectors being at a different fixed location relative to a focal point of said focused split beams;
• and
• determining the distance to the web using output signals from each said array of light detectors.

On a paper machine, a method of determining a distance to a moving web, comprising the steps of:

• focusing the light from a light source onto the web using a lens;
• collecting light that is reflected and scattered from the web using said lens;
• focusing the collected light toward an array of light detectors;
• and
• determining the distance to the web using output signals from said array of light detectors.

On a paper machine, a method of determining a distance to a moving web, comprising the steps of:

• focusing the light from a light source onto the web using a lens;
• collecting light that is reflected and scattered from the web using said lens;
• focusing the collected light toward a bundle of fiber ends in a fiber optic cable;
• guiding light focused on a center area of said fiber ends to one light detector and guiding light focused on other areas of said fiber ends to a plurality of other light detectors;
• and
• determining the distance to the web using output signals from each said light detector.