Fig. 3
From: Automated recognition and analysis of body bending behavior in C. elegans
The general process of feature point extraction algorithm. a The original grayscale image whose head and tail coordinates have been marked. b Clean binary image of nematode. c The contour point division of the nematode body. The red side is the dorsal side of the nematode, and the blue side is the ventral side of the nematode. d The centerline of nematode. e The pharynx of nematode, is marked with a purple dot. f The inflection points of the centerline of the nematode's body is marked by blue dots. g The peak points of the centerline of the nematode body, are marked by yellow dots. The red line is the line between the pharynx and the tail of the nematode. The vertical distance di from the peak point to the line is indicated by a dotted green line. h The angle αi between each peak point and two adjacent inflection points