1. A correlation filter for determining if a physical test target in at least one test image obtained using an imaging device matches a physical training target in at least one training image, comprising: a) a conjugate transpose module configured to generate a conjugate transpose S H of an image matrix S that includes at least one training image vector, each of the at least one training image vector including a vectorized representation of the at least one training image; b) a power spectrum module configured to generate a power spectrum matrix D x using at least one test image vector x, each of the at least one test image vector x including a vectorized representation of the at least one test image; and c) a correlation processor configured to generate correlation-peak-strength and distance-from-origin data using the conjugate transpose SH and power spectrum matrix D x according to h=(D x +ÎµI) âˆ’1 S[S H (D x +ÎµI) âˆ’1 S] âˆ’1 d; and wherein: i) Îµ is a regularization constant; ii) I is an identity matrix; and iii) D x is a vector desired response with elements corresponding to at least one of the at least one training image vector in matrix S.