Aperture compensation method based on projection error

To address the errors caused by the non-coincidence of the hole surface with the calibration plane in machine vision-based aperture measurement, as well as the edge degradation encountered during edge extraction, an aperture diameter compensation method based on perspective projection error was proposed. Edge detection was performed using an adaptive median filtering algorithm, and the aperture diameter was determined by employing quadratic curve invariant. Perspective projection error was then introduced to obtain the corrected hole diameter. A visual inspection experimental platform was constructed, and the test results demonstrate that the proposed compensation method achieves a measurement error within ± 0.002 mm, and a measurement accuracy of 0.001 mm. The method demonstrates a better compensation effect and can meet the enterprise's accuracy requirements.