Detection of skin line in computed radiographs for improved tone scale

An algorithm for the detection of the skin-line transitions in computed radiographic imagery is presented. Knowledge of the gray-level values associated with the skin-line transition can be utilized by a tone-scaling algorithm to prevent the loss of visibility of the skin line. Features associated with the line profile of the significant transitions (in terms of gray-level value) are used to identify the skin-line transition in digital radiographs. A Gaussian maximum likelihood classifier is used to separate the skin-line transitions from those associated with the background-foreground, background-hardware, and other significant transitions. Results are presented for a set of operational computed radiography exams.