Error calibration method for electric field positioning demodulation system

Abstract

The invention relates to the technical field of electric field positioning in medical instruments, and in particular to an error calibration method for an electric field positioning demodulation system. The method comprises the following steps: calculating the size of a DFT sampling window and DFT processing frequency; calculating an amplitude and a phase value of an obtained electric field signalby combining a real part and an imaginary part of an electric field signal subjected to short-time sliding DFT demodulation; calculating amplitude values and phase values obtained by DFT demodulationin different directions on different channels; carrying out normalization processing on the amplitude values and the phase values to obtain a gain and a phase error vector; performing calculating toobtain a final amplitude value and a phase value after calibration in different directions on different channels; and obtaining a calibrated positioning coordinate of a catheter. Compared with the prior art, the method saves resource consumption of FFT in acquiring an amplitude and phase of specific frequency; real-time performance, convenience and stability of positioning are enhanced; and the gain error and the phase error of different channels are subjected to normalized calibration to obtain a relatively accurate relative position relation.

Description

technical field [0001] The invention relates to the technical field of electric field positioning in medical equipment, in particular to an error calibration method for an electric field positioning demodulation system. Background technique [0002] Catheter ablation is currently the routine treatment for complex arrhythmias. During the operation, the precise positioning of the ablation catheter is a key factor for the smooth progress of the operation. The positioning method can be divided into two-dimensional plane positioning and three-dimensional space positioning according to the different presentation methods. The two-dimensional method mainly uses X-rays to irradiate the human body to obtain a perspective view of the human body in a specific orientation, so that the exact position of the catheter in the human body can be observed. There are obvious defects in this method, that is, patients and medical staff must be exposed to radiation for a long time, which will caus...

AI Technical Summary

Problems solved by technology

The difficulty of this method is to restore the carrier locally. In the demodulation process, devices such as digitally controlled oscillators or phase-locked loops are often required, and the circuit is very complicated.

Because the effect of recovering the carrier signal is directly related to the final output effect and error, the requirements for the device are extremely high and it consumes a lot of resources.

At the same time, when multiple positioning electrodes are positioned at the same time, the slight difference in the capacitance distribution in the circuit will cause the phase delay of the signal, and the difference between the amplifiers will also cause a gain error, which will lead to inaccurate final measurement results

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