Figure 2
From: Digital image processing to detect subtle motion in stony coral
Displacements of the coral tissue surface from digital image correlation. (a) The displacements \(u_{x}\) along horizontal direction between the reference picture and the second picture at day and night are shown in the left and right panel, respectively. (b) The displacement \(u_{y}\) along vertical direction between the reference picture and the second picture at day and night are shown in the left and right panel, respectively. Green curves in (a) and (b) represents the edge of the fragment and white curves enclose the polyps. (c) The percentage histograms of displacement \(u_{x}\) and displacement \(u_{y}\) are shown in the left and right panels, respectively. The red and blue curves indicate the means of each displacement during day and night. The pink and cyan regions are variations during day and night, respectively.
