Automatic microscopic focus system and method for analysis of transparent or low contrast specimens

摘要

A microscope system and method empirically determines the boundaries of the depth of field of an objective lens. The system and method are largely automated, with the manipulation of a specimen to be imaged being carried out by processors and associated equipment. Calculations of the empirical depth of field are also likewise automated. Upon empirically determining the boundaries of the depth of field, the specimen, particularly when transparent or translucent, can be accurately imaged at user-defined depths smaller than the depth of field.

主权项

1. A method for empirically determining a boundary of the depth of field of an objective lens of a microscope system by employing a transparent specimen, the microscope system having a microscope, an F-stop, an image sensor, and one or more processors, the method comprising the steps of:
placing a focal face of a transparent specimen at a first position outside of the depth of field of the objective lens, wherein the focal face is chosen from a proximal focal face, relative to the objective lens, and a distal focal face, relative to the objective lens; projecting an edge of the F-stop onto the focal face at the first position to produce an F-stop projection thereon; effecting incremental relative movement between the specimen and the objective lens to place the focal face of the specimen at different incremental positions relative to the objective lens and projecting an edge of the F-stop to produce an F-stop projection on the focal face at said incremental positions, wherein said step of effecting incremental relative movement brings the focal face to a position at the boundary of the depth of field; electronically imaging, with the image sensor, the F-stop projection on the focal face at the first position and the incremental positions; performing a contrast analysis of the images of the F-stop projection on the focal face at the first position and at the incremental positions as provided by the image sensor in said step of electronically imaging, said step of performing a contrast analysis being carried out by said one or more processors and establishing when the focal face is at a position at the boundary of the depth of field.