Automatic segmentation and classification of seven-segment display digits on auroral images

• Published in: Geoscientific Instrumentation, Methods and Data Systems
• Main Authors: Savolainen, Tuomas, Keith Whiter, Daniel, Partamies, Noora
• Other Authors: Design Factory, University of Southampton, University Centre in Svalbard, Aalto-yliopisto, Aalto University
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Sodankylä; Northern Finland
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/25564; https://doi.org/10.5194/gi-5-305-2016

In this paper we describe a new and fully automatic method for segmenting and classifying digits in seven-segment displays. The method is applied to a dataset consisting of about 7 million auroral all-sky images taken during the time period of 1973-1997 at camera stations centred around Sodankylä observatory in northern Finland. In each image there is a clock display for the date and time together with the reflection of the whole night sky through a spherical mirror. The digitised film images of the night sky contain valuable scientific information but are impractical to use without an automatic method for extracting the date-time from the display. We describe the implementation and the results of such a method in detail in this paper. Peer reviewed