An adaptive enhanced focusing technique for whole slide imaging using contextual information

Abstract

Optical imaging systems especially microscopy systems under higher magnifications often have relatively limited depth of field. This constraint results in partial focusing in the image. To overcome this partial focusing problem, enhanced focusing (EF) techniques are introduced to generate all-well-focused images. A sequence of images for each field is acquired at the same image field and along the same optical axis at different acquisition depths. The images are partitioned into tiles where the best focused sub-images for each tile among the sequence is found. The final image is the mosaicking of the found sub-images. Whole slide imaging (WSI) is an emerging imaging technology since the mid-1990s. It automatically acquires digital images from a biomedical slide field by field using robotic microscopic devices at high resolution and then stitches them together to form a large-dimensional high-resolution montage. Each field is just a small window of the large scene of the slide. In the context of WSI, all fields are to be focused and such an EF-WSI procedure could be very slow. In this work, we have proposed a new adaptive focusing method using contextual information in the slide for EF-WSI. We can reduce about 1/3 of computation time while maintaining good image quality.