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Fig. 7 | EURASIP Journal on Image and Video Processing

Fig. 7

From: Inner lips feature extraction based on CLNF with hybrid dynamic template for Cued Speech

Fig. 7

The left figure shows lips ROI with CLNF lips landmarks (20 black stars). The blue line in the left figure corresponds to the middle point of the inner lower lips, and all the curves in the right figure are plotted according to this blue line. On the right figure, the blue curve is the original luminance variation. The red curve is the smoothed luminance. The green curve is the first derivative of the smoothed luminance. Four lines with blue, red, green, and magenta colors correspond to four middle CLNF landmarks around the blue middle line in the left figure. In (a), the luminance decreases from the teeth to lower lips which corresponds to a local minimal point in the right figure. In (b, c), it becomes complicated to find the local minimal point corresponding to lower inner lips boundary. However, the outer lower lips boundary is always corresponding to a local minimal point on the local “V” curve in the right figure for these three cases

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