Image Analysis Procedure
While shaking the trees an image analysis procedure using 300 frames per second was used to determine the rate of fruit removal. This image analysis procedure was implemented to determine the harvest rate of fruit removal over time for the total duration of the shake tests. The recorded video images were analyzed with the “Tracker” software developed by Douglas Brown and the “Image J” software developed by Wayne Rasband.
A white target was placed on the ground as a reference frame for the image analysis. The area of harvested fruits covering the white reference was correlated with number of pixels in the framed image. The higher the number of fruit covering the white frame the higher the number of computed pixels. The use of the this approach made it possible to look at the video images frame by frame to extract the information while the tree was being harvested by the particular shaker head. The high-speed videos were recorded at a speed of 300 frames per second.
Figures 1, 2 & 3 (below) illustrate the process: Figure 1 shows a sample image of the white target used as a reference and the respective image with the corresponding number of computed pixels. Figure 2 below shows typical images of actual harvested fruits, right, analyzed and converted to pixels. Figure 3 demonstrates how a typical percent area of harvested fruit divided by the original reference frame area was obtained.