title: Why correlation uses multiplication rather than subtraction in signal matching?
body: <p>When correlating two signals or data set, would not subtracting give more accurate match between two signals rather that convolution, i.e less the error (by subtraction), gives an idea on how similar the signals are. Also convolution adds up DC offset which may bringing the value of correlating two different signals to have higher value than similar signals. (Which can be solved by subtracting means from signal)</p>