Method and apparatus for measuring the surface of an object

Claim 2

In a method of measuring and recording the circumferential surface of an article moving continuously along a longitudinal axis thereof, the steps comprising: impinging at least one laser beam at an angle with said longitudinal axis onto at least a portion of said circumferential surface to form an illuminated spot thereon, the characteristics of the laser rays reflected from the illuminated spot varying in dependence of the topography of said circumferential surface, scanning said part of said circumferential surface with the laser beam, the laser beam having a point of origin, measurable and reference distances being defined between said point of origin and said circumferential surface, reflecting the laser beam from said circumferential surface, focusing the reflected laser beam so as to obtain a focal image of the illuminated spot, said focal image having a substantially predetermined diameter and defining with the illuminated spot an optical axis, defocused spot regions existing on opposite sides of the focal image along the optical axis, measuring the light intensity within said predetermined diameter along said defocused spot regions and said focal image, the light intensity reaching a peak when said predetermined diameter coincides with said focal image, the peak corresponding to said reference distance being defined as a reference peak, the peaks corresponding to said measurable distances being defined as measured peaks, respectively, and measuring the time deviation between said reference peak and corresponding of said measured peaks, the distance from the origin of the laser beam to said circumferential surface being determinable solely as a function of said time deviation between said reference peak and corresponding of said measured peaks, and said reference distance, respectively, transforming the measured time deviations obtained into recordable electrical signals, and recording said electrical signals.

Claim 3

A method as defined in claim 1, wherein said impinging step includes focusing the laser beam onto said surface.

Claim 4

A method as defined in claim 1, wherein the article is elongated, and has a longitudinal axis, and further comprising the step of moving the article along the longitudinal axis, the laser beam subtending a predetermined angle with the longitudinal axis.

Claim 5

A method as defined in claim 1, wherein the scanning step is performed within a frequency range of approximately 1 to 10 Hertz.

Claim 6

A method as defined in claim 1, and further comprising additional impinging, measuring, and scanning steps relating to another part of said surface, and synchronizing all of said impinging, measuring and scanning steps with one another.

Claim 7

A method as defined in claim 5, wherein all of said impinging steps are performed so as to scan at least mutually adjacent regions of the surface being measured, and wherein said synchronizing step includes converting the electrical signals into a single signal representative of the entire topography of said surface.

Claim 8

A method as defined in claim 6 and further comprising the step of visually displaying said single signal.

Claim 9

A method as defined in claim 1, and further comprising the step of displaying the results of the measuring step in visual form.

Claim 10

A method as defined in claim 1, further comprising the step of continuously rotating said laser beam around said article.

Claim 11

A method as claimed in claim 1 further comprising the step of smoothing out said measured deviations prior to the transformation thereof to said electrical signals.

Claim 14

A laser-optical system for measuring the circumferential surface of an article moving continuously along a longitudinal axis thereof comprising, in combination: means for directing at least one laser beam at an angle with said longitudinal axis onto the circumferential surface to be measured to form an illuminated spot thereon, the laser rays reflected from the illuminated spot varying in dependence on the topography of the circumferential surface; means for scanning the laser beam across said circumferential surface, wherein said laser beam has a point of origin, a plurality of measurable distances, inclusive of a reference distance, being defined between said point of origin and said circumferential surface to be measured, means for measuring the characteristics of the laser rays reflected from the illuminated spot, including a light stop and moving means for periodically moving said light stop between two extreme positions in an additional light path, an intermediate point between said two extreme positions corresponding to said reference distance, the illuminated light spot being substantially focusable onto said light stop at a plurality of determinable distances from one of said extreme positions, so as to define peaks of light intensity occurring at measurable time deviations from respective predetermined time slots, each predetermined time slot corresponding to said reference distance, each measurable time deviation corresponding to a respective measurable incremental distance from said reference distance, the sum of respective incremental distances and of said reference distance corresponding to said measurable distances, whereby said measurable distances, and consequently, a contour of a cross-section of said article is obtainable from said measurable time deviations.

Claim 15

A laser-optical system for measuring the circumferential surface of an article moving continuously along a longitudinal axis thereof comprising, in combination: means for directing at least one laser beam at an angle with said longitudinal axis onto the circumferential surface to be measured to form an illuminated spot thereon, the laser rays reflected from the illuminated spot varying in dependence on the topography of the circumferential surface; means for scanning the laser beam across said circumferential surface, wherein said laser beam has a point of origin, a plurality of measurable distances, inclusive of a reference distance, being defined between said point of origin and said circumferential surface to be measured, means for measuring the characteristics of the laser rays reflected from the illuminated spot, including a light stop and moving means for periodically moving said light stop between two extreme positions in an additional light path, an intermediate point between said two extreme positions corresponding to said reference distance, the illuminated light spot being substantially focusable onto said light stop at a plurality of determinable distances from one of said extreme positions, so as to define peaks of light intensity occurring at measurable time deviations from respective predetermined time slots, each predetermined time slot corresponding to said reference distance, each measurable time deviation corresponding to a respective measurable incremental distance from said reference distance, the sum of respective incremental distances and of said reference distance corresponding to said measurable distances, whereby said measurable distances, and consequently, a contour of a cross-section of said article is obtainable from said measurable time deviations.

Claim 16

A system as defined in claim 12, wherein the means for directing the laser beam into the surface includes a laser from which the laser beam exits in one direction for travel in a predetermined path, and further comprising: a collimating lens and a collecting lens arranged in series in said path, and wherein said means from measuring said characteristics includes a one-way mirror extending across, and at an acute angle to said path, and being permeable to the laser beam traveling in said one direction, but at least partly reflecting any light rays traveling in said path opposite to said one direction into said additional path, and a light sensor arranged in said additional path.

Claim 17

A system as defined in claim 13, and wherein said means for measuring said characteristics further includes an additional collecting lens arranged in said additional path between said one-way mirror and said light sensor.

Claim 18

A system as defined in claim 13, further comprising voltage-controlled oscillator means postcoupled to said light sensor for smoothing said measurable time deviations so as to obtain a smooth contour of said cross-section of said article.

Claim 19

A system as defined in claim 12, further comprising smoothing means connected to said moving means for providing a substantially continuous signal corresponding to said determinable distances.

Claim 20

A system as defined in claim 16, wherein said moving means includes an oscillator, and wherein said smoothing means includes a lock-in detector having two inputs, and an output, one of said inputs being connected to said light sensor, the other to said oscillator, said output providing said substantially continuous signal.

Claim 21

A system as defined in claim 16, further comprising signal evaluating means including a measurement result decoder connected to said smoothing means, an electronic data processor connected to said decoder, and parameter-feeding, and indicating means connected to said data processor.

Claim 22

A system as defined in claim 12, wherein said means for directing one laser beam onto said surface, said means for measuring said characteristics, and said means for scanning the laser beam across said surface together form a laser-optical unit; and further comprising a ring-shaped support member, and wherein said laser-optical unit is mounted on said support member for being circumferentially adjusted thereon.

Claim 23

A system as defined in claim 19, further comprising at least one additional laser-optical unit, similar to said laser-optical unit, and also mounted on said support member, and circumferentially adjustable thereon.

Claim 24

A system as defined in claim 12, wherein said means for scanning the laser beam across the surface includes a refracting grating having a controllable index of refraction.

Claim 25

In a method of measuring and recording the circumferential surface of an article moving continuously along a longitudinal axis thereof, the steps comprising: impinging at least one laser beam at an angle with said longitudinal axis onto first and second positions of said circumferential surface to form illuminated spots thereon, the characteristics of the laser ray reflected from the illuminated spots varying in dependence of the topography of said circumferential surface, scanning said positions of said circumferential surface with the laser beam, the laser beam having a point of origin, measurable and reference distances being defined between said point of origin and said circumferential surface, reflecting the laser beam from said first and second positions of said circumferential surface, focusing the reflected laser beam so as to obtain focal images of the illuminated spots, each focal image having a substantially predetermined diameter and defining with each illuminated spot an optical axis, defocused spot regions existing on opposite sides of each focal image along the optical axis, measuring the light density within said predetermined diameter along corresponding of said defocused spot regions and said focal image, the light intensity reaching a peak when said predetermined diameter coincides with said focal image, the peak corresponding to said reference distance being defined as a reference peak, the peaks corresponding to said measurable distances being defined as measured peaks, respectively, and measuring the time deviation between said reference peak and corresponding of said measured peaks, the distance from the origin of the laser beam to said circumferential surface being determinable solely as a function of said time deviation between said reference peak and corresponding of said measured peaks, and said reference distance, respectively, transforming the measured time deviations into recordable electrical signals, recording said electrical signals, and synchronizing all of said impinging, measuring and scanning steps with one another.

Claim 26

In a method of measuring and recording the circumferential surface of an article moving continuously along a longitudinal axis thereof, the steps comprising: impinging at least one laser beam at an angle with said longitudinal axis onto first and second positions of said circumferential surface to form illuminated spots thereon, the characteristics of the laser ray reflected from the illuminated spots varying in dependence of the topography of said circumferential surface, scanning said positions of said circumferential surface with the laser beam, the laser beam having a point of origin, measurable and reference distances being defined between said point of origin and said circumferential surface, reflecting the laser beam from said first and second positions of said circumferential surface, focusing the reflected laser beam so as to obtain focal images of the illuminated spots, each focal image having a substantially predetermined diameter and defining with each illuminated spot an optical axis, defocused spot regions existing on opposite sides of each focal image along the optical axis, measuring the light density within said predetermined diameter along corresponding of said defocused spot regions and said focal image, the light intensity reaching a peak when said predetermined diameter coincides with said focal image, the peak corresponding to said reference distance being defined as a reference peak, the peaks corresponding to said measurable distances being defined as measured peaks, respectively, and measuring the time deviation between said reference peak and corresponding of said measured peaks, the distance from the origin of the laser beam to said circumferential surface being determinable solely as a function of said time deviation between said reference peak and corresponding of said measured peaks, and said reference distance, respectively, transforming the measured time deviations into recordable electrical signals, recording said electrical signals, and synchronizing all of said impinging, measuring and scanning steps with one another.