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Fig. 5 | Plant Methods

Fig. 5

From: Quantifying cereal crop movement through hemispherical video analysis of agricultural plots

Fig. 5

Signal processing visual. The red color value for each frame is normalized to the red color value for the red square on the panel, generating a waveform of both plant movement and outdoor lighting conditions over the video (Column a). The waveforms in column a are then bandpassed, centering the signal at 0 and removing the low frequency (< 0.5 Hz) components of the signal (Column b). Peaks within the bandpassed signals are identified with a minimum prominence of 0.005 Normalized Red Value, with the distance between each peak (in frames) calculated and divided by the frame rate to estimate the natural frequency (ωn, in Hz) to the next peak. The mean of the distribution of these frequencies constitutes the ωn for the plot (Column c—red lines)

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