Biodiversity Information Science and Standards : Conference Abstract
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Conference Abstract
Assessing Herbarium Specimen Image Quality with FineFocus
expand article infoAnne Barber, C. Skema, Michelle Mancini, Timothy Block
‡ University of Pennsylvania, Philadelphia, United States of America
Open Access

Abstract

The Mid-Atlantic Megalopolis Thematic Collections Network, a digitization project funded by the U.S. National Science Foundation, seeks to digitize ca. 800,000 herbarium specimens through imaging, transcription, and georeferencing. 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. The FineFocus technique provides a way of assessing contrast, as a proxy for focus quality, through analysis of a standard text target using two freeware programs run through a batch script. By calculating a numeric value, this protocol provides an objective way to obtain a high level of focus quality for a specific imaging rig with given conditions before proceeding with imaging. Adjusting focus with FineFocus yields noticeably sharper images, allowing users to see fine details otherwise obscured by poor focus, such as secondary venation. This technique can be easily implemented in herbarium digitization workflows to improve the quality of specimen images.

Keywords

digitization, herbarium, imaging

Presenting author

Anne Barber

Funding program

Advancing Digitization of Biodiversity Collections (ADBC)

Grant title

The Mid-Atlantic Megalopolis: Achieving a greater scientific understanding of our urban world