SWEEP MEASURING SCHEME

• US 3,806,253 A
• Filed: 12/13/1972
• Issued: 04/23/1974
• Est. Priority Date: 12/13/1972
• Status: Expired due to Term

• Current Assignee: Eric B. Denton
• Original Assignee: Eric B. Denton
• Inventors: Denton, Eric B.
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Morrison, Steven K.
• Application Number:
  US05/314,850
• Time in Patent Office: 496 Days
• Field of Search: 250/219TH,209 144/312,29R,29A,29B,29C 350/138,139,146,157,156,163,167
• US Class Current: 356/601
• CPC Class Codes: G01B 11/105 using photoelectric detection means
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01B 5/0035 Measuring of dimensions of trees
• CPC Class Codes: G01V 8/20 using multiple transmitters or receivers

Abstract

A system for measuring the sweep of an object, particularly logs, where sweep may be defined as the spatial deviation of the actual center line of the log from an imaginary line drawn as if the log had been perfectly true. The system utilizes two light sensitive detectors, placed at a distance from the log and spaced apart at a substantial angle. Each sensor obtains information concerning the cross-section of the log relative to the sensor'"'"''"'"'s location. Known methods of triangulation, utilizing the information obtained from the two sensors, are then used to determine the center point of the log at a first location of the log. Successive determinations are then made of the log at predetermined intervals, and the results compared with those of first location to determine the sweep at the successive log locations.

Claims

1. A method for determining the sweep of an elongated object comprising the steps of:

measuring a geometric center point of an elongated object at a first specified location along the longitudinal axis of said elongAted object relative to a first fixed three-dimensional reference axis, which reference axis substantially parallels the longitudinal direction of said object;

measuring a geometric center point of said elongated object at a second specified location along said longitudinal axis relative to said fixed reference axis; and

comparing said first and second measurements, a difference between said first and second measurements being indicative of the sweep of said elongated object at said second location, relative to said first location.

2. The method according to claim 1, including the step of measuring a geometric center point of said elongated object at more than two specified locations in the longitudinal direction of said elongated object, each of said measurements being made with respect to said fixed reference axis, said measurements being made in a plane normal to said longitudinal direction of said elongated object at each specified location.

3. The method according to claim 2 wherein the steps of measuring include detecting two opposing edges of said elongated object relative to each of at least two reference points removed from the surface of said elongated object, said reference points being angularly removed from one another and lying substantially in said plane normal to said longitudinal direction of said elongated object at each said specified location.

4. The method according to claim 3 wherein the step of measuring includes actuating at least two light sensitive detectors located at said reference points, output signals of each of said detectors being dependent upon the outside dimensions of said elongated object with respect to each of said detectors.

5. The method according to claim 4 wherein said elongated object is a log, substantially round in cross section.

6. The method according to claim 5 wherein said measurements are made at successive intervals of no more than four feet along the longitudinal axis of the log.

7. A method in accordance with claim 6 wherein the step of comparing includes comparing each of said measurements at said specified locations with said measurement at said first specified location.

8. The method according to claim 1 wherein the steps of measuring include positioning a plurality of sensors around an elongated object, each of said plurality of sensors being located substantially in a plane normal to the longitudinal direction of said elongated object, at each said specified location, each sensor being actuated so as to provide output signals related to the location of a plurality of center lines through said geometric center of said elongated object in said plane from each of said sensors, the intersection of said plurality of center lines indicating the geometric centerpoint of said elongated object in said first plane.

9. The method according to claim 8 wherein the steps of measuring include determining a first angle relative to a first sensor of said plurality of sensors, said first angle extending from a connecting line connecting said first sensor and a second sensor to a first center line associated with said first sensor, said first center line passing through a point equidistant from the two opposite edges of said elongated object visible to said first sensor, said first angle indicative of the location of said first center line associated with said first sensor.

10. The method according to claim 9 wherein the steps of measuring further include determining a second angle relative to a second sensor of said plurality of sensors, said second angle extending from said connecting line to a second center line associated with said second sensor, said second center line passing through a point equidistant from the two opposite edges of said elongated object visible to said second sensor, said second angle indicative of the location of said center line associated with said second sensor passing through said geometric center of said elongated object in said plane, and determining the intersection of said center liNes associated with said first and second sensor, said intersection occurring at a point within said elongated object, representing the geometric centerpoint of said elongated object in said first plane.

11. The method according to claim 10 wherein said plurality of sensors is actuated by light which is reflected from said elongated object.

12. The method according to claim 1 wherein the steps of measuring include positioning at least two light sensitive detectors at a distance from said elongated object, said detectors being receptive to light from at least one light source, and moving said elongated object and said detectors in relation to one another such that said elongated object passes between said light source and each of said detectors.

13. The method according to claim 12 including the step of determining a lateral distance traveled by said elongated object, as said elongated object passes between said elongated light source and said elongated object during a period wherein light is blocked from a specified photo detector by said elongated object.