US 5,790,710 A · Autofocus system for scanning microscopy

Abstract

Reliable autofocus is required to obtain accurate measurements of fluorescent stained cellular components from a system capable of scanning multiple microscope fields. Autofocus could be performed directly with fluorescence images, but due to photobleaching and destructive fluorescence by-products, it is best to minimize fluorescence exposure for photosensitive specimens and live cells. This exposure problem could be completely avoided by using phase-contrast microscopy, implemented through the same optics as fluorescence microscopy. Functions for both phase-contrast and fluorescence autofocus were evaluated using the present invention and the suitability of phase-contrast autofocus for fluorescence microscopy was determined. The present autofocus system for scanning microscopy can be performed at least as fast as 0.25 s/field without loss of precision.

Claims20

Dependent claims

A sequential method of autofocus for a microscope having a focus mechanism, the method comprising:

scanning a specimen on a microscope stage;
sequentially receiving digital images of the specimen at a plurality of vertical positions along a Z axis;
for each vertical position of the plurality of vertical positions:
applying a digital filter to a digital image acquired at the vertical position to obtain a filtered image;
and
applying a measurement function to the filtered image to obtain a value representing a degree of focus;
applying a weight to the value representing a degree of focus to obtain a weighted value;
applying a non-interative function to a plurality of weighted values of focus to obtain a focus position;
and
causing the microscope stage to move to a vertical position corresponding to the focus position.

7 more elements

Dependencies are inferred from the claim text.

Autofocus system for scanning microscopy

Life of this patent

Autofocus system for scanning microscopy

Life of this patent

Abstract

Claims20