Count on this

In November 2010, Nursery Management readers were the first to learn about the concept of using an aerial platform and object-based software to automate the inventory process. Since 2010, our collaborative team of researchers has made great strides in counting field- and container-grown plants in open-field settings. This progress has been made possible by continued efforts of the team, funding by the Oregon Association of Nurseries, and the addition of graduate students at Arkansas and Florida.

The key to the success of this collaborative effort is to find or develop grower-friendly software that can reliably count plants in production settings. Since software specific to plant inventory does not currently exist, the team is using a two-pronged approach to move forward. Ying She, a Ph.D. student at the University of Florida, is developing her own image processing solution that could be developed into a stand-alone software program for plant inventory. Josue Leiva Lopez, a MS student at the University of Arkansas, is trying to adapt off-the-shelf object- based (OB) software. Typically OB software is used to identify objects in satellite images. Table 1 (see page 30) illustrates some preliminary results from an analysis of images using two different software programs. Both students are early in their graduate programs, so it is too premature to know how robust these programs are in counting plants under a variety of nursery conditions. However, the team is optimistic that it is moving in a positive direction.

The University of Florida and Oregon State University have also been conducting some preliminary research on taking individual images that are subsequently stitched and then analyzed using OB software. Plant count of images stitched from video taken at a Florida nursery was 98 percent accurate. The group is also interested in comparing images taken individually versus images extracted from a video file. Oregon State University has been working on still and video images collected over Christmas tree farms. Plant counts have been as high as 97 percent. All of these efforts are focused on addressing broader issues related to the collection and processing of images from large production blocks or fields. Blocks of newly planted plants are fairly easy to count; however, during shipping season, rows or blocks of plants begin to look like Swiss cheese, making human counts difficult.

The foundational objective of these collective efforts is to either develop from scratch, or adapt currently available OB software, to count and analyze for inventory purposes, plants in open-field nurseries. In either case, the process is dependent on obtaining aerial images on an as-needed basis. This is another aspect of this research project that is pushing the technology envelope. Since May 2010 the team has been utilizing a lightweight unmanned aerial vehicle (UAV) to obtain images.
 

While this aspect of the project may be the most “cool,” it has also proven the most frustrating. In May 2010 the research team began to encounter challenges regarding the use of UAV’s commercially. Public and commercial use of UAVs is currently caught in a quagmire of interim rules from the FAA. This is a clear example of technology outpacing regulations. We are hopeful that the operational guidelines to be released by September 2015 will allow for increased public and commercial uses of UAVs. Other hurdles include solar flare and weather impact on flights, battery life and durability of aerial platforms, to mention a few.

Even with these significant challenges, the collaborative team is still optimistic that a practical system can be developed to help automate certain aspects of the inventory process for open-field nurseries. Stay tuned as we continue our adventure.

The team would like to express their thanks to J. Frank Schmidt & Sons Nursery (Boring, Ore.), Bailey Nurseries (Yamhill, Ore.), Yule Tree Farm (Aurora, Ore.), Greenleaf Nursery (Park Hill, Okla.), Brantley Nurseries (Winter Garden, Fla.), Cherry Lake Tree Farm (Groveland, Fla.), Parks Brothers Greenhouses (Van Buren, Ark.) and the Oregon Association of Nurseries.

Authors: Jim Robbins, extension horticulture specialist (jrobbins@uaex.edu), and Josue Nahun Leiva, graduate assistant, University of Arkansas, Division of Agriculture; Ying She, Ph.D. student, and Reza Ehsani, associate professor, University of Florida; Jim Owen, assistant professor of horticulture, Virginia Tech; Dharmendra Saraswat, associate professor, University of Arkansas, Division of Agriculture; Joe Mari Maja, postdoctoral association, University of Florida; Heather Stoven, faculty research assistant, and Chal Landgren, professor, Oregon State University.