Photo GRID: A Graphic Tool to Process Aerial Images for ...zzlab.net/GRID/napb_2019_GRID.pdf ·...

Zhiwu.Zhang@wsu.edu

Photo GRID: A Graphic Tool to Process Aerial Images for High-Throughput Phenotyping

Chunpeng James Chen and Zhiwu ZhangDepartment of Crop and Soil Sciences, Washington State University, Pullman, WA 99164, USA

ProblemsAerial images have shown their great potential in high-throughput phenotyping, being able to saveconsiderable manual work in the field investigation andaccelerate the breeding process. However, to define thearea of interest (AOI) from an image, it usually requiresintensive time and effort from researchers. The existinganalytical software either ask users to draw the areamanually or request stringent-defined files beforecarrying out any further analyses. In this work, we'representing a python package,GRID (GReenField Image Decoder),that is designed to alleviate abovechallenges in this type of analyses.

ObjectivesPrecision

Define area of interest with less background noiseincluding shaded areas.

EfficiencyIncrease the efficiency by providing several built-inalgorithms that are commonly used in image analyses.

InteractiveWrap the workflow into an intuitive graphical userinterface (GUI). From this GUI, users can interactivelypreview the results given different settings in real-time.

AcknowledgementThis project was in part supported by USDA, DOE, NSF, Washington State University and Washington Grain Commission.

Reference1. Bradski, G. The OpenCV Library. Dr. Dobb’s journal of Software Tools. (2000)2. Stéfan van der Walt, S. Chris Colbert and Gaël Varoquaux. The NumPy Array: A

Structure for Efficient Numerical Computation, Computing in Science &Engineering, 13, 22-30 (2011)

http://zzlab.netChun-Peng.Chen@wsu.edu

Results / ConclusionsTo show the performance of GRID, we usednumber of AOI pixels as predictions on alfalfabiomass from an aerial image (fig. 1a). The AOIdefined manually (in QGIS) took around 6 hours tofinish and have mild accuracy (R2=0.47). Whereasone made by GRID only took seconds andproduced much more accurate results (R2=0.7).Hence, GRID can not only save researchers’ timebut achieve more convincing results.

Methods/Interface

Figure 1a. Raw image of alfalfa canopy; 1b. Pixel-wiseclustering by k-mean clustering; 1c. Assign clusters asvegetation area based on the cluster centers; 1d. Removebackground noise and shaded area by 2-d convolutionaloperations; 1e. Find all the local maxima by comparisonsof neighboring values; 1f. Dynamically expand theboundaries from its local maximum point.

Figure 2. Interface of GRID.

Figure 3. Correlation between alfalfa biomass and predictionlearned from manually-defined (Left) and GRID-defined AOI (Right).