Method for automatic detection of a relevant part for a digital X-ray detector using a filtered histogram

摘要

A method for automatically forming a filtered subset of digital values from a first set of digital values corresponding to a plurality of picture elements representing a radiographic exposure of a subject for use in displaying a radiograph of said subject, the method comprising: (1) generating a first histogram of the first set of digital values; (2) generating an integral curve representing an integral of the first histogram; (3) identifying an inflection point and corresponding digital value Vpeak1 on the first histogram integral where the integral curve first changes slope in a direction decreasing from the highest digital value; (4) calculating a parameter Vtest=Vpeak1-AR wherein AR represents an anatomical range of the subject; (5) spatially dividing the first set of digital values into multiple block subsets of digital values, each block subset comprising digital values from a neighborhood of pixels consisting of a predetermined number of picture elements; (6) constructing a subset histogram representing the frequency of occurrence of digital values within each block subset; (7) determining a low point of each block subset, BVlow, corresponding to a predetermined low point of the subset histogram; (8) comparing each BVlow to Vtest; and (9) forming the filtered subset of digital values from the digital values of all the block subsets having BVlow greater than Vtest.