Getting Started Using a UAV for Generating Field Imagery: Creating Orthomosaic Images

An orthomosaic is an aerial panorama that has been generated using computer software that geometrically corrects and connects overlapping images to make a uniform photograph. Unlike uncorrected aerial photographs, an orthophotograph can be used to gauge true distances, because it is a true representation of the Earth's surface. We use orthomosaics to better understand management practices for agricultural producers by surveying fields for irrigation water distribution, plant health assessments, field plant stand counts, and plant growth determinations. There are many different programs available to make these types of pictures. We have used free programs such as Microsoft Image Composite Editor (ICE), moderately priced programs such as Stitcher 4 and a higher priced program, Agrisoft Photoscan. We found that Photoscan is a robust program that can import large numbers of field pictures, required for large fields when captured by a small UAV (Unmanned Aerial Vehicle) platform. Microsoft Ice and Stitcher 4 are able to complete an orthomosaic rendering that contains a small set of pictures but at times struggles with larger image sets. This presentation will review the basic steps in generating an orthomosaic from a small collection of images that were captured by a UAV. While all software programs discussed in this presentation can generate othomosiac imagery, careful consideration must be employed when selecting an appropriate program to utilize.