Combination of Top-Hat and Bottom-Hat Transforms for Frequency Estimation

A frequency of the signal generally is estimated using conventional strategies based on Fourier transforms. This method uses a complex calculation process and also need to combine with other strategies in order to get a good estimation, and as a result, making a burden in a calculation and time-consuming in their process. In this paper, the combination of the top-hat and bottom-hat transforms is presented as a new strategy in estimating the frequency of the signal in the time domain. These methods, top-hat and bottom-hat transforms are based on Mathematical Morphology that using simple calculations and as a result reducing the complexity of the calculations. In this strategy, the signal is processed using both transforms, then the results are compared with each other to find the frequency estimation of the signal. The results of the simulation in Matlab show this strategy has the ability to estimate the frequency of the signal accurately for both noise-free signal and signal with SNR at higher than 30dB specially for the frequency between 30 to 100 Hz.