Grupe, Dirk Bernhard Willi

A method (300) for calibrating a measuring head (105; 405; 505) comprises positioning (305) the measuring head (105; 405; 505) relative to a calibration object (O) such that the calibration object (O) is in the measuring field (M) of the measuring head (105; 405; 505) in accordance with a calibration position of the measuring head (105; 405; 505) and the calibration object (O); varying (310) a position of a variable mirror arrangement (122, 124) of the measuring head (105; 405; 505); receiving (315), from the variable mirror arrangement (122, 124), one or more position signals (SP) indicative of the varying position of the variable mirror arrangement (122, 124); operating (320) a laser device (110) of the measuring head (105; 405; 505), comprising switching the laser device (110) between an activated state and a deactivated state in accordance with a calibration dynamic projection pattern (CDP1; CDP2) depending on the varying position of the variable mirror arrangement (122, 124), the varying position of the variable mirror arrangement (122, 124) determined based at least partially on the one or more position signals (SP) and one or more calibration parameters applied to the one or more position signals (SP); receiving (325), from an image sensor arrangement (130, 132, 134), image sensor data (SL1, SL2) indicative of a varying position of scattered light (L_S) of the laser beam (L_D) in at least one image plane of the image sensor arrangement (130, 132, 134), the scattered light (L_S) comprising light (L_S) of the laser beam (L_D) which has been scattered by the calibration object (O) towards the image sensor arrangement (130, 132, 134); identifying (335), based on an analysis of image information (210; 220) encoded in the image sensor data (SL1, SL2), at least one topographic landmark of the calibration dynamic projection pattern (CDP1; CDP2) represented in the image information (210; 220); determining (340) a deviation between a position of the at least one topographic landmark in the image information (210; 220) and a reference position of the at least one topographic landmark; determining (345), based on the deviation, one or more replacement calibration parameters configured to compensate at least partially the deviation when, in the operating (320) of the laser device (110), the varying position of the variable mirror arrangement (122, 124) is determined based at least partially on the one or more position signals (SP) and the one or more replacement calibration parameters applied to the one or more position signals (SP), wherein determining (345) the one or more replacement calibration parameters is performed at least partially based on a geometric model which comprises a set of geometric angles (φ, ϑ, α, β, γ, ε), the set of geometric angles (φ, ϑ, α, β, γ, ε) representing at least the varying position of the variable mirror arrangement (122, 124), in particular with respect to a body of the measuring head (105; 405; 505), and a direction of the deflected laser beam (L_D) with respect to the varying position of the variable mirror arrangement (122, 124); and, setting (350) the one or more replacement calibration parameters as the one or more calibration parameters.

An Optical Coherence Tomography, OCT, device (100; 200; 410), in particular for an endoscopic measuring system (400), comprises at least one light source (110; 210); at least one cascaded interferometer arrangement (120, 140; 220, 240) having at least a first interferometer (120; 220) configured to receive light (L_S) emitted by the light source (110; 210) and at least a second interferometer (140; 240), the second interferometer (240) arranged behind the first interferometer (120) with respect to an optical path (L_S, L_IL, L_IM) of the OCT device (100; 200; 410); at least one image sensor (180; 280); and; at least one image fiber (160; 260) arranged between the cascaded interferometer arrangement (120, 140; 220, 240) and the image sensor (180; 280) with respect to the optical path (L_S, L_IL, L_IM) of the OCT device (100; 200; 410). The image fiber (160; 260) is configured to receive at least one interferometric image (L_IM) output by the second interferometer (140; 240) and to transmit the interferometric image (L_IM) towards the image sensor (180; 280) for detection of the interferometric image (L_IM) by means of the image sensor (180; 280).

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