# US 11,994,381 B2 · Apparatus for and method of measuring surface > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,381 B2 - Document ID: US11994381B2 - Status: Granted - Kind: B2 - Application number: 17/182,797 - Filed: 2021-02-23 - Published: 2021-08-26 - Granted: 2024-05-28 - Earliest claimed: 2020-02-24 - Assignees: Senfit Oy - Applicants: Senfit Oy - Inventors: Pekka Jakkula; Juha Heikkinen; Matti Limingoja; Mikko Vuolteenaho - Web page: https://patentgrep.com/patent/US11994381B2 ## CPC - G01B 11/046: {for measuring width} - G01B 15/04: for measuring contours or curvatures - G01B 11/026: {by measuring distance between sensor and object (G01B11/0608 takes precedence)} - G01B 11/06: for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)} - G01B 15/00: Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons (characterised by the use of optical techniques G01B9/00, G01B11/00) - G01B 15/02: for measuring thickness - G01N 22/00: Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more (G01N3/00 - G01N17/00, G01N24/00 take precedence) - G01N 33/20: Metals - G01S 7/4056: {specially adapted to FMCW} - G01S 13/06: Systems determining position data of a target - G01S 13/878: {Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector (G01S13/874 takes precedence)} - G01S 13/88: Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) - G01B 2210/44: with detectors on both sides of the object to be measured - G01S 7/025: {involving the transmission of linearly polarised waves} - G01S 13/75: using transponders powered from received waves, e.g. using passive transponders {, or using passive reflectors} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract An apparatus for measuring a surface comprises first sensors, which are distributed two-dimensionally in space, said first sensors interacting with the surface in a contactless manner using a microwave range of electromagnetic signals, and the first sensors receive at least two of the microwave signals of the interaction with information relating to distances between the sensors and the surface as a reflection, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the first sensors. A data processing unit receives said information on the distances, and determines at least one geometrical parameter of the surface on the basis of the information. ## Claims ### Claim 1 An apparatus for measuring a moving surface, comprising: at least three first transceivers distributed two-dimensionally in space, at least two of the at least three first transceivers being distributed parallel with a longitudinal extent of a surface of a first edge of a sheet, the at least two first transceivers being configured to have an interaction with the surface of the first edge in a contactless manner using a microwave range of electromagnetic signals, the at least two first transceivers being configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least two first transceivers and the first edge at different longitudinal sections of the sheet, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least three first transceivers; and a data processing unit configured to receive the information, determine at least one geometrical parameter of the first edge based on the information. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the data processing unit is configured to determine an angle of the first edge with respect to a direction of a desired direction of the sheet as the at least one geometrical parameter of the sheet based on the information relating to a difference of distances between the at least two first transceivers and the surface of the sheet. ### Claim 3 (depends on 1) The apparatus of claim 1, further comprising at least two second transceivers distributed parallel with a longitudinal extent of a second edge of the sheet and opposite to the first edge; wherein the at least two second transceivers are configured to have an interaction with the surface of the second edge in the contactless manner using the microwave range of the electromagnetic signals; wherein the at least two second transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least two second transceivers and the second edge at different longitudinal sections of the sheet; and wherein the data processing unit is configured to receive the information, and determine the at least one geometrical parameter of the second edge based on the information. ### Claim 4 (depends on 3) The apparatus of claim 3, further comprising a first additional transceiver sensor that is configured to transmit a microwave signal over the sheet in a direction that has a component parallel to a normal of the first and second edges to a first reflecting reference that has a known location with respect to the at least two second transceivers; wherein the first additional transceiver sensor is configured to receive a reflection of the microwave signal from the first reflecting reference with transverse information relating to a distance between the first additional transceiver sensor and the first reflecting reference; and wherein the data processing unit is configured to receive the transverse information, and determine a width of the sheet based on the transverse information, a location of the first edge and a location of the second edge, which are included in the geometrical parameters of the first edge and the second edge. ### Claim 5 (depends on 3) The apparatus of claim 3, wherein one of the at least two first transceivers is configured to transmit a microwave signal in a direction that has a component parallel to a normal of the first edge to a second reflecting reference that is located over the sheet; wherein the one of the at least two first transceivers is configured to receive a reflection of the microwave signal from the second reflecting reference with first reference information relating to a distance between the one of the at least three first transceivers and the second reflecting reference; wherein the one of the at least two second transceivers is configured to transmit a microwave signal in a direction that has a component parallel to a normal of the second edge to a second reflecting reference; wherein the one of the at least two second transceivers is configured to receive a reflection of the microwave signal from the second reflecting reference with second reference information relating to a distance between the one of the at least two second transceivers and the second reflecting reference; and wherein the data processing unit is configured to receive the first reference information and the second reference information, and determine a width of the sheet based on the first transverse information, the second reference information, a distance between the first reflecting reference and the second reflecting reference, a location of the first edge and a location of the second edge, which are included in the geometrical parameters of the first edge and the second edge. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the at least three first transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least three first transceivers and the first edge of the sheet as a reflection in a direction parallel to a normal of the first edge, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least three first transceivers; and wherein the data processing unit is configured to receive said-the information on the distances, and determine, as the at least one geometrical parameter, a shift of the sheet in the vertical direction based on the basis of the information. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the at least three first transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least three first transceivers and a first main surface as a reflection, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least three first transceivers; and wherein the data processing unit is configured to receive the information on the distances, and compare the first main surface to a desired reference based on the distances between the at least three first transceivers and the first main surface included in the information for determining a deviation. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the at least three first transceivers comprise at least four transceivers, which are configured to receive at least three of the microwave signals of the interaction with information relating to distances between the at least four first transceivers and a first main surface as a reflection from the first main surface, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least four first transceivers; and wherein the data processing unit is configured to receive said-the information on the distances, and determine a waviness of the first main surface based on differences of the distances between the at least four first transceivers sensors and the first main surface included in the information. ### Claim 9 (depends on 7) The apparatus of claim 7, further comprising at least three second transceivers at a known distance from the at least three first transceivers; wherein the at least three second transceivers are distributed two-dimensionally in space, the at least three second transceivers being configured to have an interaction with a second main surface of a sheet opposite to the first main surface in a contactless manner using a microwave range of electromagnetic signals, and at least two of the at least three second transceivers being configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least three second transceivers and the second main surface as a reflection, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least three second transceivers; and wherein the data processing unit is configured to receive the information on the distances, and determine a thickness of the sheet based on the distances between the at least three first transceivers and the first main surface, between the at least three second transceivers and the second main surface included in the information from both sides of the sheet, and the known distance between the at least three first transceivers and the at least three second transceivers. ### Claim 10 (depends on 1) The apparatus of claim 1, comprising: one or more processors; and one or more memories including computer program code; wherein the one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus at least to receive the information on the distances, and determine the at least one geometrical parameter based on the information. ### Claim 11 A method of measuring a surface, the method comprising: transmitting, with at least three first transceivers, electromagnetic signals of a microwave range to the surface for causing an interaction with the surface in a contactless manner, the at least three first transceivers being distributed two-dimensionally in space; receiving, by at least two of the at least three first transceivers at least two of the microwave signals of the interaction with information relating to distances between the at least three first transceivers and the surface as a reflection, the microwave signals of the interaction representing both dimensions of the space of the two-dimensional distribution of the at least three first transceivers, the microwave signals of the interaction representing both dimensions of the space of the two-dimensional distribution of the at least three first transceivers; and receiving, by a data processing unit, the information on the distances, and determining, by the data processing unit, at least one geometrical parameter of the surface based on the information. ### Claim 12 (depends on 2) The apparatus of claim 2, further comprising at least two second transceivers distributed parallel with a longitudinal extent of a second edge of the sheet and opposite to the first edge; wherein the at least two second transceivers are configured to have an interaction with the surface of the second edge in the contactless manner using the microwave range of the electromagnetic signals; wherein the at least two second transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least two second transceivers and the second edge at different longitudinal sections of the sheet; and wherein the data processing unit is configured to receive the information, and determine the at least one geometrical parameter of the second edge based on the information. ### Claim 13 (depends on 11) The method of claim 11, further comprising determining an angle of the first edge with respect to a direction of a desired direction of the sheet as the at least one geometrical parameter of the sheet based on the information relating to a difference of distances between the at least two first transceivers and the surface of the sheet. ### Claim 14 (depends on 13) The method of claim 13, wherein at least two second transceivers are distributed parallel with a longitudinal extent of a second edge of the sheet and opposite to the first edge; wherein the at least two second transceivers are configured to have an interaction with the surface of the second edge in the contactless manner using the microwave range of the electromagnetic signals; wherein the at least two second transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least two second transceivers and the second edge at different longitudinal sections of the sheet; and wherein the data processing unit is configured to receive the information, and determine the at least one geometrical parameter of the second edge based on the information. ### Claim 15 (depends on 11) The method of claim 11, wherein at least two second transceivers are distributed parallel with a longitudinal extent of a second edge of the sheet and opposite to the first edge; wherein the at least two second transceivers are configured to have an interaction with the surface of the second edge in the contactless manner using the microwave range of the electromagnetic signals; wherein the at least two second transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least two second transceivers and the second edge at different longitudinal sections of the sheet; and wherein the data processing unit is configured to receive the information, and determine the at least one geometrical parameter of the second edge based on the information. ### Claim 16 (depends on 15) The method of claim 15, wherein a first additional transceiver sensor that is configured to transmit a microwave signal over the sheet in a direction that has a component parallel to a normal of the first and second edges to a first reflecting reference that has a known location with respect to the at least two second transceivers; wherein the first additional transceiver sensor is configured to receive a reflection of the microwave signal from the first reflecting reference with transverse information relating to a distance between the first additional transceiver sensor and the first reflecting reference; and wherein the data processing unit is configured to receive the transverse information, and determine a width of the sheet based on the transverse information, a location of the first edge and a location of the second edge, which are included in the geometrical parameters of the first edge and the second edge. ### Claim 17 (depends on 15) The method of claim 15, wherein one of the at least two first transceivers is configured to transmit a microwave signal in a direction that has a component parallel to a normal of the first edge to a second reflecting reference that is located over the sheet; wherein the one of the at least two first transceivers is configured to receive a reflection of the microwave signal from the second reflecting reference with first reference information relating to a distance between the one of the at least three first transceivers and the second reflecting reference; wherein the one of the at least two second transceivers is configured to transmit a microwave signal in a direction that has a component parallel to a normal of the second edge to a second reflecting reference; wherein the one of the at least two second transceivers is configured to receive a reflection of the microwave signal from the second reflecting reference with second reference information relating to a distance between the one of the at least two second transceivers and the second reflecting reference; and wherein the data processing unit is configured to receive the first reference information and the second reference information, and determine a width of the sheet based on the first transverse information, the second reference information, a distance between the first reflecting reference and the second reflecting reference, a location of the first edge and a location of the second edge, which are included in the geometrical parameters of the first edge and the second edge. ### Claim 18 (depends on 11) The method of claim 11, wherein the at least three first transceivers comprise at least four transceivers, which are configured to receive at least three of the microwave signals of the interaction with information relating to distances between the at least four first transceivers and a first main surface as a reflection from the first main surface, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least four first transceivers; and wherein the data processing unit is configured to receive the information on the distances, and determine a waviness of the first main surface based on differences of the distances between the at least four first transceivers and the first main surface included in the information. ### Claim 19 (depends on 11) The method of claim 11, wherein the at least three first transceivers are configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least three first transceivers and a first main surface as a reflection, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least three first transceivers; and wherein the data processing unit is configured to receive the information on the distances, and compare the first main surface to a desired reference based on the distances between the at least three first transceivers and the first main surface included in the information for determining a deviation. ### Claim 20 (depends on 19) The method of claim 19, wherein at least three second transceivers are provided at a known distance from the at least three first transceivers; wherein the at least three second transceivers are distributed two-dimensionally in space, the at least three second transceivers being configured to have an interaction with a second main surface of a sheet opposite to the first main surface in a contactless manner using a microwave range of electromagnetic signals, and at least two of the at least three second transceivers being configured to receive at least two of the microwave signals of the interaction with information relating to distances between the at least three second transceivers and the second main surface as a reflection, the microwave signals of the interaction representing both dimensions of the space of two-dimensional distribution of the at least three second transceivers; and wherein the data processing unit is configured to receive the information on the distances, and determine a thickness of the sheet based on the distances between the at least three first transceivers and the first main surface, between the at least three second transceivers and the second main surface included in the information from both sides of the sheet, and the known distance between the at least three first transceivers and the at least three second transceivers.