Journal: PLoS ONE
Article Title: How Lovebirds Maneuver Rapidly Using Super-Fast Head Saccades and Image Feature Stabilization
doi: 10.1371/journal.pone.0129287
Figure Lengend Snippet: (A) The downstroke / upstroke phase ratio vs . instantaneous flap frequency distribution for individual wingbeats of five birds. A phase ratio of 1 indicates up- and downstrokes of equal duration, values <1 indicate longer upstrokes, values >1 longer downstrokes. Normalized bimodal Gaussian fits are shown for flap frequency (top) and for downstroke / upstroke time ratios (right). The bird-specific bimodal distribution parameters for the flapping frequency are: 2dg: μ 1 = 9.78, σ 1 = 1 . 61 , μ 2 = 17.26, σ 2 = 1 . 01 ; 2lg: μ 1 = 10.26, σ 1 = 1 . 83 , μ 2 = 18.14, σ 2 = 0 . 91 ; 2y: μ 1 = 9.39, σ 1 = 1 . 1 , μ 2 = 17.19, σ 2 = 0 . 86 ; 1y: μ 1 = 8.97, σ 1 = 0 . 6 , μ 2 = 15.76, σ 2 = 0 . 96 ; 3g: μ 1 = 9.49, σ 1 = 2 . 3 , μ 2 = 16.72, σ 2 = 1 ; For downstroke / upstroke periods the obtained bimodal distribution parameters are: 2dg: μ 1 = 0.5, σ 1 = 0.07, μ 2 = 1.26, σ 2 = 0.27; 2lg: μ 1 = 0.56, σ 1 = 0.13, μ 2 = 1.43, σ 2 = 0.17; 2y: μ 1 = 0.48, σ 1 = 0.07, μ 2 = 1.26, σ 2 = 0.27; 1y: μ 1 = 0.62, σ 1 = 0.09, μ 2 = 1.49, σ 2 = 0.17; 3g: μ 1 = 0.48, σ 1 = 0.12, μ 2 = 1.3, σ 2 = 0.17. The horizontal gray line separates the bimodal distributions at a downstroke / upstroke ratio of 0.94 (average midpoint between bimodal distribution peaks among birds). The vertical gray line separates the bimodal distribution at a flap frequency of 13.3 Hz (average among birds); n = 697 wing beats, N = 5 birds. Due to the 2000 fps sample frequency, and the fact that wingbeat, downstroke, and upstroke time are all integer values measured in number of frames, the data appear in a raster and can overlap precisely among wings beats, flights and birds. (B) The normalized saccade distributions illustrate when a saccade was started and ended during the downstroke vs . the upstroke phase. Shown is the average across birds (solid lines) and the standard deviation (shaded area). Binning: 0:10:100; n = 72 saccades, N = 5 birds.
Article Snippet: Wingbeat and downstroke / upstroke periods were analyzed for bimodal distributions using the Gaussian mixture models algorithm (GMM) of the MATLAB statistics toolbox.
Techniques: Standard Deviation