Abstract
Great efforts are presently taken in the scientific community to develop computerized and (fully) automated image processing methods allowing for an efficient and automatic monitoring of sea birds and marine mammals in ever-growing amounts of aerial imagery. Currently the major part of the processing, however, is still conducted by especially trained professionals, visually examining the images and detecting and classifying the requested subjects. This is a very tedious task, particularly when the rate of void images regularly exceeds the mark of 90%. In the content of this contribution we will present our work aiming to support the processing of aerial images by modern methods from the field of image processing. We will especially focus on the combination of local, region-based feature detection and piecewise global image segmentation for automatic detection of different sea bird species. Large image dimensions resulting from the use of medium and large-format digital cameras in aerial surveys inhibit the applicability of image processing methods based on global operations. In order to efficiently handle those image sizes and to nevertheless take advantage of globally operating segmentation algorithms, we will describe the combined usage of a simple performant feature detector based on local operations on the original image with a complex global segmentation algorithm operating on extracted sub-images. The resulting exact segmentation of possible candidates then serves as a basis for the determination of feature vectors for subsequent elimination of false candidates and for classification tasks.
Highlights
Since fall 2013, the monitoring of sea birds and marine mammals in the context of environmental impact studies concerning offshore wind energy plants within the German exclusive economic zone (EEZ) is relying solely on digital aerial imaging
Great efforts are presently taken in the community to develop computerized image processing methods allowing an efficient and automatic processing of the ever-growing amounts of aerial imagery
The northern band was captured using a Vexcel UltraCam Eagle equipped with a 260Mpx sensor and a 100.5 mm lens at a ground sampling distance (GSD) of approx. 0.03m
Summary
Since fall 2013, the monitoring of sea birds and marine mammals in the context of environmental impact studies concerning offshore wind energy plants within the German exclusive economic zone (EEZ) is relying solely on digital aerial imaging. Whereas images captured at good conditions show a homogeneous dark water surface which makes it easy to detect individual bird subjects, survey flights conducted in acceptable but non-perfect conditions often result in image data where the dark water surface is cluttered with artefacts from sun glitter, wave crests and disturbed water. These artefacts usually manifest themselves as bright or white, saturated image areas in different sizes and of irregular shape which massively complicate the processing (both, manually as well as automated) of those images. - The impact of the GSD of aerial image data on the performance of the above method
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
