Cross correlation

Cross-correlation is a measurement that tracks the movements of two or more sets of time series data relative to one another. It is used to compare multiple time series and objectively determine how well they match up with each other and, in particular, at what point the best match occurs.

1. What is the formula for cross-correlation?
2. What is cross-correlation of two signals?
3. What is cross-correlation of two vectors?
4. What is the difference between cross-correlation and Pearson correlation?

What is the formula for cross-correlation?

Cross-correlation between X_i and X_j is defined by the ratio of covariance to root-mean variance, ρ i , j = γ i , j σ i 2 σ j 2 . γ ^ i , j = 1 N ∑ t = 1 N [ ( X i t − X ¯ i ) ( X j t − X ¯ j ) ] .

What is cross-correlation of two signals?

Correlation of two signals is the convolution between one signal with the functional inverse version of the other signal. The resultant signal is called the cross-correlation of the two input signals. The amplitude of cross-correlation signal is a measure of how much the received signal resembles the target signal.

What is cross-correlation of two vectors?

Cross-correlation measures the similarity between a vector x and shifted (lagged) copies of a vector y as a function of the lag. If x and y have different lengths, the function appends zeros to the end of the shorter vector so it has the same length as the other.

What is the difference between cross-correlation and Pearson correlation?

In the realm of statistics, cross-correlation functions provide a measure of association between signals. The Pearson product-moment correlation coefficient is simply a normalized version of a cross-correlation. When two times series data sets are cross-correlated, a measure of temporal similarity is achieved.