Submitted to: National Agricultural Aviation Association Meeting
Publication Type: Proceedings
Publication Acceptance Date: 4/13/2007
Publication Date: 5/10/2007
Publication URL: http://apmru.usda.gov/Aerial/2006ASAE/AA06-001paper.pdf
Citation: Thomson, S.J., Price, R.R., Smith, L. 2007. Integrating Spray Plane-Based Remote Sensing and Rapid Image Processing with Variable-Rate Aeral Application. NAAA/ASABE Paper No. AA06-001. National Agricultural Aviation Association, Washington, D.C. Available: http://apmru.usda.gov/Aerial/2006ASAE/AA06-001paper.pdf Interpretive Summary: Agricultural aircraft can serve as a complete solution for precision aerial application of agrichemicals as they are convenient and easily scheduled platforms. Remote sensing of field variables has been demonstrated to work well from this platform to provide data for site specific application or targeted spraying of chemical. An example remote sensing application from a weed detection experiment showed success in discriminating weeds from crop and in distinguishing broadleaf from grass weeds. A variable rate flow controller was tested for flowrate accuracy and its ability to change spray rates at the desired field location. Tests showed a slightly delayed system response to an abrupt change in flowrate from 0 to 210 L/min. This was partially due to the method used to activate the pump. Position error for aiming spray at a specified field target was less than 5.2 meters when switching from zero flow to 56 L/ha. A missing link for a totally integrated variable rate aerial application system has been a near real-time method to analyze and reference images to GPS coordinates so that their data could be processed quickly for generation of field prescriptions. Preliminary testing of an image processing method showed that GPS error could be reduced by accounting for errors that are consistent between runs and improving synchronization of GPS position data with images.
Technical Abstract: A remote sensing and variable rate application system was configured for agricultural aircraft. This combination system has the potential of providing a completely integrated solution for all aspects of aerial site-specific application and includes remote sensing, image processing and georegistration, prescription generation, and variable-rate application. A missing link has been the ability to rapidly process and georeference images obtained during flight for creation of field prescriptions that can be applied on the next pass of the airplane. Success using the remote sensing system for detection of weeds is described, and evaluation of a variable-rate system indicated fast response to changing flowrates and accurate placement of material in preliminary testing. Evaluation of a scheme for rapid image processing showed that georegistration error could be reduced by accounting for systematic GPS error and improving synchronization of GPS position data with images.