Steerable focal adjustment for optical coherence tomography

A method of surface inspection of an object using optical coherence tomography (OCT), the OCT comprising a steerable scanner head, the scanner head having an associated depth of field comprising a distance range, a working distance comprising a distance from the scanner head to a respective region on the surface of the object, the method comprising:

• determining a present angle of the steerable scanner head where the working distance to a present region on the surface of the object is within the distance range of the depth of field;
• steering the steerable scanner head to the present angle;
• and
• performing a scan of the object at the present region.

A system for surface inspection of an object using optical coherence tomography (OCT), the system comprising:

• a steerable scanner head for performing a scan of the object by directing optical beams towards the object and detecting optical beams returning from the object, the scanner head having an associated depth of field comprising a distance range, a working distance comprising a distance from the scanner head to a respective region on the surface of the object;
• and
• a steering module to:
• determine a present angle of the steerable scanner head where the working distance to a present region on the surface of the object is within the distance range of the depth of field;
• and
• steer the steerable scanner head to the present angle where the steerable scanner head performs the scan of the object.