Filtering ultrasonic echo of bottom sediment in drilling hole by parameters constrained gabor filter

Ultrasonic is a good means to measure the thickness of bottom sediment in drilling hole. The echo signal of the sediment is weak and with high noise usually. This paper adopts Gabor filter to process the ultrasonic echos. The constrainted relationships between Gabor filter´s parameters and frequency characteristics have been analyzed and presented. The time-domain standard deviation sigma_t and oscillation frequency f₀ of the filter are designed by these relationship and the features of ultrasonic transducer. Some echos including noise with different intensity have been filtered by the designed Gabor filter. The results show that Gabor filter is suitable for processing the ultrasonic echo and its effect of improving the SNR is much prominent especially when the included noise is very high.