This document discusses high accuracy camera calibration. It covers the importance of robust calibration and current approaches using tools like OpenCV and Matlab that can have errors. Problems are identified with locating features precisely and systematic noise from location and luminance errors. The document introduces achieving subpixel accuracy through techniques like digital image correlation on circular markers and bundle adjustment that accounts for real feature locations. It emphasizes eliminating errors from correlation and optimization to contribute improved calibration methods to open source tools like OpenCV.