As reported in the official ImgBurn guide,
Performing Optimum Power Calibration (OPC ) is a special technique used in newer CD/DVD recordable drives to perform a test write and read in an area inside of the lead-in, in order to determine the best laser power for recording and to adjust to each recordable disc, which may vary slightly from different manufacturers, or for other reasons.
I don't know if your drive support OPC
However, the default setting in ImgBurn is disabled, and I don't use it.
The purpose of OPC is to improve writing quality when using low quality media, to be sure that the disc will be burned at the best speed. However, using low quality discs is anyway a risk, because no drive can transform them in good discs.
Using good quality media OPC becomes pretty useless.