Method for reducing phase errors due to CCD nonlinearity

The three-step phase-shifting and mean value methods are combined to reduce phase errors due to charge coupled device (CCD) nonlinearity. The CCD nonlinearity induced phase error value is obtained by combining the output fringe intensity phase values obtained from ideal and nonlinear CCD after phase unwrapping. Assuming CCD nonlinearity, the new phase value is offset by π/3 from the ideal CCD result. The mean of the new and original phase error values yields the final phase error value. The CCD nonlinearity induced phase errors are significantly reduced using our method than with previous methods. Computer simulation and experimental results verify the correctness of the basic principle analysis.