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Title: ALGORITHMS FOR PARAMETERIZATION OF DYNAMICS OF INERTIA-BASED APPLE ORIENTATION

Author
item Lefcourt, Alan
item NARAYANAN, PRIYA - GRAD STUDENT, UMBC
item TASCH, URI - PROFESSOR, UMBC
item ROSTAMIAN, ROUBEN - PROFESSOR, UMBC
item Kim, Moon
item Chen, Yud

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2007
Publication Date: 6/1/2008
Citation: Lefcourt, A.M., Narayanan, P., Tasch, U., Rostamian, R., Kim, M.S., Chen, Y.R. 2008. Algorithms for parameterization of dynamics of inertia-based apple orientation. Applied Engineering in Agriculture. 24(1):123-129.

Interpretive Summary: Development of machine vision systems to inspect fruit for quality and contamination problems has been stalled due to lack of a commercially-viable method for appropriately orienting fruit for imaging. We recently discovered that apples could be oriented based-on inertial properties. Apples were rolled down a ramp consisting of two parallel rails. When the angular velocity reached a threshold, the apples repositioned themselves so that the stem/calyx axis was perpendicular to the direction of travel and parallel to the plane of the track. Many question remain concerning the underlying dynamic principles that govern this phenomenon. A photographic studio was constructed and an imaging system was developed to allow movies of the orientation process to be acquired. Software was written to allow detailed parameterization of the dynamics of the orientation process. Sequential 640x480 monochrome images are acquired at 60 fps and 1/500 sec exposure. The images are converted to movies using the AVI-format, and software was written to find the center of the apple in each frame as well as the center of the stem or calyx region if it is visible in the frame. As preliminary tests indicated that the compliance of the track plays a key role in the orientation process, the software also measures the movement (oscillation) of the track over time. The software-derived parameters are written to a text file to allow for more detailed analyses of orientation dynamics. Narrative: The use of automated systems to inspect fruit during processing offers the potential to increase the safety and quality of food consumed by the public. Such systems use cameras to take pictures of the fruit and computer software to determine if the fruit is contaminated, or if it is damaged or diseased. For apples, attempts to use automated inspection have been hindered by the difficulty of differentiating the stem and calyx regions of the apple from problem areas. One way of improving the effectiveness of automated inspection is to orient fruit prior to taking pictures so that the location of the stem and calyx is known. We discovered that rolling apples down a track consisting of two parallel rails can orient apples so that the location of the stem or calyx is always in the same location. To get a better understanding of factors that effect this orientation process, computer software was written that identifies the apple in each frame of a movie of an apple rolling down the track as well as the location of the stem or calyx, if it is visible in the frame. The software also monitors the movement of the track, as track flexing seems to be an important factor in the orientation process. This software will facilitate development of a practical system for orienting apples for imaging.

Technical Abstract: Development of machine vision systems to inspect fruit for quality and contamination problems has been stalled due to lack of a commercially-viable method for appropriately orienting fruit for imaging. We recently discovered that apples could be oriented based-on inertial properties. Apples were rolled down a ramp consisting of two parallel rails. When the angular velocity reached a threshold, the apples repositioned themselves so that the stem/calyx axis was perpendicular to the direction of travel and parallel to the plane of the track. Many questions remain concerning the underlying dynamic principles that govern this phenomenon. A photographic studio was constructed and an imaging system was developed to allow movies of the orientation process to be acquired. Software was written to allow detailed parameterization of the dynamics of the orientation process. Sequential 640x480 monochrome images are acquired at 60 fps and 1/500 sec exposure. The images are converted to movies using the AVI-format, and software was written to find the center of the apple in each frame as well as the center of the stem or calyx region if it is visible in the frame. As preliminary tests indicated that the compliance of the track plays a key role in the orientation process, the software also measures the movement (oscillation) of the track over time. The software-derived parameters are written to a text file to allow for more detailed analyses of orientation dynamics.