Multiple-peak model fitting function for DCT sign phase correlation with non-integer shift precision

We propose two fitting functions for shift estimation using discrete cosine transform sign phase correlation (DCT-SPC) with non-integer accuracy. The DCT-SPC can be used in order to estimate the shift values and the similarity between two signals. However, the estimated shift values are limited to integer numbers. The proposed fitting functions enable the DCT-SPC to estimate the non-integer shift values using only the sign of the DCT coefficients. The multiple-peak model in the proposed fitting functions provides more accurate values than other models. Simulations are presented to demonstrate the effectiveness of the proposed fitting functions.