AUTOFOCUS METHOD AND APPARATUS FOR IMAGING MICROSCOPY USING A PREDETERMINED VISUAL IMAGING FEATURE

A method of, and apparatus for, automatically focussing a microscope objective (18). The apparatus includes an image detector (26) for obtaining an image, through the microscope objective, of a surface having at least one visual feature. The apparatus further includes a processor (28) for determining, from the image, a plurality of overlapping curves, each of which represents a quality of focus for different areas of the feature. The apparatus also includes an actuator (32), controlled by the processor, for positioning the microscope objective at an optimum focus position, relative to the surface, based upon the shape, specifically the sign of the slope, of the overlapping curves.