title: Using shape contexts method for registration of contra lateral breasts in thermal images.
abstract: OBJECTIVE
  To achieve symmetric boundaries for left and right breasts boundaries in thermal images by registration.
  
  
  METHODS
  The proposed method for registration consists of two steps. In the first step, shape context, an approach as presented by Belongie and Malik was applied for registration of two breast boundaries. The shape context is an approach to measure shape similarity. Two sets of finite sample points from shape contours of two breasts are then presented. Consequently, the correspondences between the two shapes are found. By finding correspondences, the sample point which has the most similar shape context is obtained.
  
  
  RESULTS
  In this study, a line up transformation which maps one shape onto the other has been estimated in order to complete shape. The used of a thin plate spline permitted good estimation of a plane transformation which has capability to map unselective points from one shape onto the other. The obtained aligning transformation of boundaries points has been applied successfully to map the two breasts interior points. Some of advantages for using shape context method in this work are as follows: (1) no special land marks or key points are needed; (2) it is tolerant to all common shape deformation; and (3) although it is uncomplicated and straightforward to use, it gives remarkably powerful descriptor for point sets significantly upgrading point set registration. Results are very promising. The proposed algorithm was implemented for 32 cases. Boundary registration is done perfectly for 28 cases.
  
  
  CONCLUSIONS
  We used shape contexts method that is simple and easy to implement to achieve symmetric boundaries for left and right breasts boundaries in thermal images.
authors.affiliation: Mahnaz Etehadtavakol, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan University, Isfahan 81745-319, Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Etehadtavakol
authors.affiliation: Mahnaz Etehadtavakol, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan University, Isfahan 81745-319, Iran.
authors.forename: Eddie Yin-Kwee
authors.initials: EY
authors.lastname: Ng
authors.affiliation: Mahnaz Etehadtavakol, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan University, Isfahan 81745-319, Iran.
authors.forename: Niloofar
authors.initials: N
authors.lastname: Gheissari
keywords: Breast thermal images; Cancer detection; Infrared; Registration; Shape contexts