Patent ID: 6094152
Filing Date: 2000-07-25
Classification: A61N

Abstract:
A system for setting an analog to digital (A/D) window control for image acquisition in a radiotherapy system comprising the steps of:means for setting an initial estimate of a dark region within a histogram, the histogram including pixel counts and pixel values related to the pixel counts;means for determining two dominant peaks inside the dark region, one of the two dominant peaks being below a first predetermined value and the other of the two dominant peaks being between the first predetermined value and a second predetermined value, if the one dominant peak is more than two times the standard deviation of the other dominant peak, then a first local minimum to the right of the one dominant peak will be the revised boundary, if the other dominant peak is more than two times the standard deviation of the one dominant peak, then a first local minimum to the left of the other dominant peak will be the revised boundary; otherwise the average value of the two dominant peaks will be the revised boundary;means for counting the number of pixels outside the revised boundary;means for determining a mean pixel value outside the revised boundary based upon the pixel count;means for accumulating pixel counts in one direction from the mean pixel value until a predetermined percentage of the pixel counts outside the revised boundary is reached to determine the lower cutoff value;means for accumulating pixel counts in an opposite direction form the one direction from the mean pixel value until a predetermined percentage is reached to determine the upper cutoff value; andmeans for utilizing the upper and lower cutoff values to set the A/D window.