Abstract Detail

Biodiversity Informatics & Herbarium Digitization

Skema, Cynthia [1], Barber, Anne [1], Mancini, Michelle [1], Block, Timothy [1].

FineFocus: A tool for the objective evaluation of focus quality in herbarium specimen imaging.

The use of autofocus alone in herbarium specimen imaging with a digital single-lens reflex camera does not yield consistently sharp images, even with relatively two-dimensional specimens and a proper selection of focus point. These disparities in focus quality may have a negative impact on downstream use of specimen images in research, e.g., in morphometric work. Employing contrast as a proxy for focus quality, the FineFocus technique provides a numeric value reflective of focus quality through the analysis of an image of a standard text target, using two freeware programs run through a batch script. The resulting values are both specimen- and condition-dependent, and therefore only comparable for images of a single sheet taken with a specific imaging rig with identical settings (e.g., aperture, lighting levels). FineFocus can be used as a tool to objectively evaluate focus quality in developing imaging protocols for a digitization workflow, and can also be used as a step within an imaging protocol to "lock in" a high level of focus quality before proceeding with imaging specimens. This work was developed through the Mid-Atlantic Megalopolis Project, a digitization project funded by the National Science Foundation's Advancing Digitization of Biodiversity Collections program.

Related Links:
MAM Project website
MAM Portal

1 - Morris Arboretum Of The University Of Pennsylvania, 100 E. Northwestern Ave., Philadelphia, PA, 19119, United States

Keywords:
herbarium specimen imaging
herbarium digitization
focus quality
digitization workflow.

Presentation Type: Oral Paper
Session: 12, Biodiversity Informatics & Herbarium Digitization
Location: 105/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 2:15 PM
Number: 12004
Abstract ID:356
Candidate for Awards:None