Patent ID: 6748257
Filing Date: 2004-06-08
Classification: A61B,G16H,Y10S

Abstract:
A system for detecting a ribcage boundary for computer-aided diagnosis requiring anatomical structure information to be detected from a digital chest image, comprising:means for obtaining a horizontal profile of smoothed pixel-value integrated averages in each of right and left lung fields of the image in the vicinity of &frac15; lung length; means for deciding a threshold for each of the right and left lung fields with each of the horizontal profiles taken as a reference; means for searching each of the right and left lung fields from a central part of each lung field outwardly on the digital chest image so as to determine a position exceeding each of the thresholds when the position being set as an outer search limit point for a series of upper lung ribcage boundary candidate points for a ribcage boundary; means for calculating a first derivative of the horizontal profile for examining changes in pixel value within each of the right and left lung fields in cases when the position exceeding each of the thresholds is not found; and means for searching not only a position from the central part of each of the right and left lung fields outwardly on the digital chest image within a predetermined search range, the position showing a maximum change in the first derivative, but also a position showing a maximal value in the horizontal profile within the search range for each of the right and left lung fields; and means for deciding a median between the maximal value and the position showing a maximum change in the first derivative as the outer search limit point for each of the right and left lung fields.