Method for assessing a depression, in particular a bore, in a workpiece

A device for examining or measuring at least one wall portion of a depression introduced into a workpiece by means of an optical measurement method, wherein the device introduces at least one light beam into the depression through a lance, and wherein the device measures by means of the at least one light beam the geometry or reflectivity of the at least one wall portion, wherein the device is designed such that for each circumferential region in the direction of a longitudinal extension of the lance at least five adjacent pixels are detected by a sensor array of the device or pixels detected in the direction of the longitudinal extension of the lance correspond to at least 0.1 μm on the circumferential region of the lance by the sensor array of the device, wherein the device rotates the lance about the longitudinal extension of the lance or moves the lance along the longitudinal extension of the lance;

• wherein the lance has at least one beam splitter which is arranged and configured to deflect the at least one light beam in such a way that the at least one light beam exits from the lance in a plurality of adjacent planes perpendicular to the longitudinal extension of the lance, and that the device is configured to guide light which has emerged and reflected back at the at least two regions through the lance and out of the lance, and to use the light outside the lance for determining the geometry or reflectivity of the at least one wall portion, wherein the device is configured to detect at least one distance value or at least one intensity or reflectivity value via each of at least two peripheral regions for at least 1,000 pixels in which the pixels have a 2- or 3-dimensional arrangement, or wherein the at least two peripheral regions each span at least 0.1 mm, or have at least an extent of five pixels or at least 0.5 μm and wherein the device is configured to determine the geometry or reflectivity interferometrically;
• wherein the at least one light beam is deflected in the depression in such a way that at least two regions of the at least one wall portion are illuminated simultaneously;
• and
• wherein the at least two regions illuminated simultaneously are disjointed.