A metal sensor and a method for the metal sensor to detect objects enclosed in a medium

Abstract

Provided are a method for detecting an object surrounded by a medium using a metal sensor, and a metal sensor. The method comprises obtaining attribute and location information about a surrounded object by analysing a measurement signal, the measurement signal being a vector signal obtained by subtracting a signal, which is generated by a receiving coil end when the sensor detects a status, from a pre-set signal, and the pre-set signal being a signal generated by the receiving coil end of the sensor without the presence of an object. The metal sensor can increase sensitivity of detection on a target object, and does not form a blind zone for measurement, which significantly improves the measurement accuracy.

Description

technical field [0001] The invention relates to the field of detection and positioning, in particular to a metal sensor and a method for the metal sensor to detect objects enclosed in a medium. Background technique [0002] Metal detectors are mainly used to locate metal objects. Existing detectors are divided into many categories and operate on various principles. For example, its main component is a sensor. The sensor is formed by a coil. The transmitting coil is used to transmit a continuous alternating field. The alternating field is received by the receiving coil. When the object to be measured is affected, the induced voltages generated on the receiving coil cancel each other out, so that the output of the induced voltage is close to 0. When the object to be measured is affected, the object to be measured will change the original alternating field, which is more accurate In other words, the object to be measured will generate another alternating field, which will be t...

AI Technical Summary

Problems solved by technology

There is following defective by this sensor location object: (1) the sensor of this prior art can only be used for detecting the existence of metal, and can't determine its attribute; (2) because transmitting coil produces a very big alternating field, and The reverse field generated by the measured object through induction is extremely small, so when detecting the alternating field generated by the extremely weak measured object, the receiving coil must ignore the alternating field generated by the huge transmitting coil, so that the receiving coil and the There is no inductive coupling in the transmitting coil. In the coil layout mode in the prior art, the first receiving wire loop 1 and the second receiving wire loop 2 must be wound in opposite directions, so that the alternating field generated by the target must also be offset to reduce the Sensitivity of detection; (3) When the object to be tested is located at a certain position, the induced voltage induced by the second magnetic field in the receiving coil will be in a state of complete cancellation, which will form a blind area of ​​measurement, and the target object cannot be detected. The target exists, that is to say, there is a measurement blind spot or the area with the lowest sensitivity; (4) Since the first coil and the second coil have different coaxial radii, changing the magnetic flux is mainly achieved by changing the area, in order to reach a larger For range compensation, the radius difference between the two coils should not be too small, it can only be realized by increasing the size of the circuit board, which will inevitably occupy the space of the circuit board

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