Automatic microscope focusing is one of the important problems with wide applications. It saves a lot of labor and time. We have developed the method of estimation of the focus position based on wavelet analysis. It uses the asymmetry of wavelet coefficients at various levels with a pronounced peak at the focus. The Figure demonstrates the application of this method to microscope focusing at a blood sample.

Clicking the next frame button, one moves the microscope to the next position, and it is shown by the red point. The peak region corresponds to the focus location.

Original cell image. Focus decision curve.
Original cell image Focus decision curve