Sample applicator sensing and positioning

Abstract

Systems and methods for positioning a sample applicator relative to a substrate include: (a) obtaining an image of the sample applicator in proximity to the substrate, where the image includes a direct image region corresponding to the sample applicator and a first reflected image region corresponding to an image of the sample applicator reflected from a surface of the substrate; (b) determining a position of an edge of the sample applicator in the direct image region; (c) determining a position of a reflected edge of the sample applicator in the first reflected image region; (d) determining a distance between the edge of the sample applicator and the reflected edge of the sample applicator; and (e) determining the position of the sample applicator relative to the substrate based on the distance between the edges.

What is claimed is: 
     
         1 . A method for positioning a sample applicator relative to a substrate, the method comprising:
 obtaining an image of the sample applicator in proximity to the substrate, the image comprising a direct image region corresponding to the sample applicator and a first reflected image region corresponding to an image of the sample applicator reflected from a surface of the substrate;   determining a position of an edge of the sample applicator in the direct image region;   determining a position of a reflected edge of the sample applicator in the first reflected image region;   determining a distance between the edge of the sample applicator and the reflected edge of the sample applicator; and   determining the position of the sample applicator relative to the substrate based on the distance between the edges.