Patent ID: 7936921

Claim:
A fixed-point digital signal processor, comprising: a processing unit; a computer readable medium coupled to the processing unit; and program code within the computer readable medium that when executed by the processing unit causes the fixed-point digital signal processor to perform: calculating a cumulative histogram of a signal; calculating a weighted histogram of the signal; calculating an objective function value without using divides, wherein calculating the objective function value without using divides comprises: calculating N−N(k) as a first value, wherein N is the cumulative histogram and N(k) is a k th cumulative histogram; calculating M·N(k) as a second value, wherein M is the weighted histogram and N(k) is the k th cumulative histogram; calculating (k·A 1 +M(k)) as a third value, wherein A 1 is the first value and M(k) is a k th weighted cumulative histogram; calculating N·M(k)+A 2 as a fourth value, wherein N is the cumulative histogram, M(k) is the k th weighted cumulative histogram, and A 2 is the second value; and calculating 2·N(k)·B 1 −B 2 as the objective function value, wherein B 1 is the third value, B 2 is the fourth value, and N(k) is the k th cumulative histogram; determining an initial estimate threshold value; calculating a threshold; and analyzing the signal with the threshold.