Determination of illuminator obstruction by known optical properties

A system, comprising a computer including a processor and a memory, the memory storing instructions executable by the processor to:

• illuminate an object external to a vehicle with an illuminator;
• determine that the object has a known optical property;
• determine the optical property of the object from a database;
• calculate luminance of the illuminator based at least on the optical property of the object;
• and
• clean a lens of the illuminator based at least on the luminance of the illuminator.

A method comprising:

• illuminating an object;
• determining the that the object has a known optical property;
• determining the optical property of the object from a database;
• calculating luminance of the illuminator based at least on the optical property of the object;
• and
• adjusting at least one of the illuminator, an image sensor, and a computer based at least on the luminance of the illuminator.