Effect of threshold selection on Ising model parameters and square density.

<p>The figure shows how parameter estimates from the Ising model change when using different threshold values to obtain binary images from decorrelation agiograms of the choriocapillaris. The threshold has been increased at 0.1 steps and applied to all images each time to calculate the density. In each plot, the blue line represents the mean of the parameter estimates at each threshold value, the red dots represent the value calculated for each image and the pink arrow point highlights the threshold value used in this study. The plot on the far left shows how the density estimate on the square area used for the Ising model calculations changes with different threshold values. As for the plot in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185256#pone.0185256.g003" target="_blank">Fig 3</a> the selected threshold is centered on the sigmoid shaped curve of the mean density values. The middle and rightmost plots show how parameter estimates from the Ising model change when using different threshold values. The selected threshold is in the center of the interval where stable measures are obtained. Note how the parameter estimates become unstable with extreme threshold values.