# US 6,724,483 B2 · Method for three-dimensionally, optically measuring measuring objects > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,724,483 B2 - Document ID: US6724483B2 - Status: Granted - Kind: B2 - Application number: 10/081,769 - Filed: 2002-02-20 - Published: 2002-10-17 - Granted: 2004-04-20 - Earliest claimed: 2001-02-21 - Assignees: Robert Bosch GmbH - Inventors: Jochen Straehle - Web page: https://patentgrep.com/patent/US6724483B2 ## CPC - G01B 9/023: for contour producing (G01B9/025 - G01B9/029 take precedence) - G01B 11/2441: {using interferometry} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A method is for three-dimensionally, optically measuring measuring objects by comparison with a reference object, where image data of the measuring object are acquired and compared to image data of the reference object, and the measuring object is directly or indirectly assessed with regard to deviations from the reference object. A quick and, at the same time, reliable assessment of the measuring object is achieved in that the measuring object and/or the reference object or a holographic recording of the measuring object and/or of the reference object are/is rotated relative to one another about at least one axis, the image data of the measuring object being acquired and the comparison being performed in various, relative rotational positions, in that an evaluation regarding a maximum agreement of the measuring object with the reference object is performed in the different comparisons, and in that the deviation is assessed in the rotational position determined by the maximum agreement. ## Claims ### Claim 1 A method for three-dimensionally, optically measuring a measuring object by comparison to a reference object, comprising the steps of: acquiring image data of the measuring object; comparing the image data of the measuring object to image data of the reference object; assessing, one of directly and indirectly, the measuring object with regard to deviations from the reference object; rotating at least one of the measuring object and the reference object relative to one another about at least one axis, the acquiring and the comparing steps being performed at various, relative rotational positions; and evaluating regarding a maximum agreement of the measuring object with the reference object in accordance with the different comparisons, the deviation being assessed in the assessing step in a rotational position in accordance with the maximum agreement. ### Claim 2 (depends on 1) The method according to claim 1, wherein the assessing step is performed during a production process. ### Claim 3 (depends on 1) The method according to claim 1, further comprising the step of storing data that three-dimensionally represent the reference object from a start in an evaluation unit, the comparing and assessing steps being performed in the evaluation unit. ### Claim 4 (depends on 1) The method according to claim 1, further comprising the step of recording image data of at least one of the measuring object and the reference object by a camera. ### Claim 5 (depends on 1) The method according to claim 1, wherein the assessing step includes the substep of directly assessing the deviations of the measuring object from the reference object following an interferometric superimposition of the measuring object and the reference object by comparing an obtained interference pattern to a reference interference pattern. ### Claim 6 (depends on 5) The method according to claim 5, further comprising the steps of: arranging one of the reference object and a holographic recording of the reference object in a reference arm of an interferometer; arranging one of the measuring object and a holographic recording of the measuring object in an object arm of the interferometer; superimposing a reference light wave from the one of the reference object and the holographic recording of the reference object and an object light wave from the one of the measuring object and the holographic recording of the measuring object at a beam splitter; and recording an interference pattern obtained by a camera. ### Claim 7 (depends on 6) The method according to claim 6, further comprising the step of obtaining a holographic recording of at least one of the reference object and the measuring object by a device configured to generate a beam path of the interferometer. ### Claim 8 (depends on 5) The method according to claim 5, further comprising the steps of: illuminating the measuring object and a light-deflecting element; directing light waves from the measuring object and the light-deflecting element at a hologram of the reference object while a hologram of the reference object is rotated; and recording light superimposed on the hologram of the reference object by a camera. ### Claim 9 (depends on 8) The method according to claim 8, further comprising the step of obtaining a holographic recording of at least one of the reference object and the measuring object by a device configured to generate a beam path of the interferometer. ### Claim 10 (depends on 1) The method according to claim 1, further comprising the assessing step includes the substep of assessing on the basis of a representation of prepared image data generated by an evaluation unit one of visually at a display device and automatically in the evaluation unit on the basis of one of predefined and predefinable criteria. ### Claim 11 A method for three-dimensionally, optically measuring a measuring object by comparison to a reference object, comprising the steps of: acquiring image data of the measuring object; comparing the image data of the measuring object to image data of the reference object; assessing, one of directly and indirectly, the measuring object with regard to deviations from the reference object; rotating a holographic recording of at least one of the measuring object and the reference object relative to one another about at least one axis, the acquiring and the comparing steps being performed at various, relative rotational positions; and evaluating regarding a maximum agreement of the measuring object with the reference object in accordance with the different comparisons, the deviation being assessed in the assessing step in a rotational position in accordance with the maximum agreement. ### Claim 12 (depends on 11) The method according to claim 11, further comprising the step of holographically recording the measuring object during a production process. ### Claim 13 (depends on 11) The method according to claim 11, wherein the assessing step is performed during a production process. ### Claim 14 (depends on 11) The method according to claim 11, further comprising the step of storing data that three-dimensionally represent the reference object from a start in an evaluation unit, the comparing and assessing steps being performed in the evaluation unit. ### Claim 15 (depends on 11) The method according to claim 11, further comprising the step of recording image data of at least one of the measuring object and the reference object by a camera. ### Claim 16 (depends on 11) The method according to claim 11, wherein the assessing step includes the substep of directly assessing the deviations of the measuring object from the reference object following an interferometric superimposition of the measuring object and the reference object by comparing an obtained interference pattern to a reference interference pattern. ### Claim 17 (depends on 16) The method according to claim 16, further comprising the steps of: arranging one of the reference object and the holographic recording of the reference object in a reference arm of an interferometer; arranging one of the measuring object and the holographic recording of the measuring object in an object arm of the interferometer; superimposing a reference light wave from the one of the reference object and the holographic recording of the reference object and an object light wave from the one of the measuring object and the holographic recording of the measuring object at a beam splitter; and recording an interference pattern obtained by a camera. ### Claim 18 (depends on 17) The method according to claim 17, further comprising the step of obtaining a holographic recording of at least one of the reference object and the measuring object by a device configured to generate a beam path of the interferometer. ### Claim 19 (depends on 16) The method according to claim 16, further comprising the steps of: illuminating the measuring object and a light-deflecting element; directing light waves from the measuring object and the light-deflecting element at a hologram of the reference object while the hologram of the reference object is rotated; and recording light superimposed on the hologram of the reference object by a camera. ### Claim 20 (depends on 11) The method according to claim 11, further comprising the assessing step includes the substep of assessing on the basis of a representation of prepared image data generated by an evaluation unit one of visually at a display device and automatically in the evaluation unit on the basis of one of predefined and predefinable criteria.