Patent ID: 11889979
Assignee: BARCO N.V.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC A  G  H | IPC A  G  H

Claim 20:
21. A method for calibrating an inspection unit for direct application to a skin surface of a patient, wherein a skin includes layers below the skin surface, said inspection unit comprising an optical array of elements comprising at least one light source having a first spectral bandwidth centred on a first wavelength, an image capturing device configured to capture images and having a field of view, a reference viewing surface through which the image capturing device is able to capture images, an imaging lens having a radius of curvature and a focal length, wherein the imaging lens is configured to define a position of a focus point of the image capturing device that extends beyond the reference viewing surface along an optical axis at said first wavelength, and a reference viewing surface, a focusing means for changing the focus position along the optical axis as a function of driving values, wherein the method comprises the steps of:
providing a fixed first calibration pattern located at a fixed position with respect to said reference viewing surface and located external to the reference viewing surface for contacting the skin surface and in the field of view of the image capturing device, the fixed first calibration pattern being located at the fixed position that is at a depth that corresponds to at least one layer of the layers of the skin below the skin surface,
capturing by the image capturing device an image of the fixed first calibration pattern, as a first image, and capturing by the image capturing device an image of the skin below the skin surface, as a second image,
establishing a relationship between adjustments of the focusing means and the positions of the focus points below the skin surface, the adjustments including a first adjustment value for the position of the focus point of the image capturing device at the fixed position of the fixed first calibration pattern,
wherein the focusing means are provided by the imaging lens which is a liquid lens, and
wherein the fixed first calibration pattern is configured to be used for focus calibration.