JPH0373885A - Ultrasonic method and device for searching internal substance with multilayer structure - Google Patents

Abstract

PURPOSE:To improve searching accuracy by changing the phase setting condition of an array sensor, analyzing the frequency of a reflected wave from a target and minimizing a half band width. CONSTITUTION:Phase conditions are set up by a phase condition setting circuit 8 so that a phase difference between two individual elements in an array sensor l is variously set up to 4.0, 4.1 to 5.9, 6.0m sec for an optimum target at 5m sec real time. Wide phase conditions are also set up in other sensors. An ultrasonic wave is transmitted in the condition corresponding to 4.0m sec phase difference to obtain a receiving waveform and extract only signals reflected from the vicinity of the target. the frequency analysis of the extracted signals is executed by a signal processing part 7 to find out a half band width W and the processing is applied to all the phase conditions to find out the width W corresponding to respective conditions. When the target is most focused, the received waveform is maximized, the width W is minimized, so that the target can be accurately searched.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention adds hardware and software improvement techniques to the ultrasonic method for array sensors. The present invention relates to a method and device for detecting internal objects in a multilayer structure using an ultrasonic method to accurately detect existing objects.

[Prior Art] Fig. 6 shows a method of measuring a multilayer structure using a conventional array sensor. In Fig. 6, 61 is an array sensor for transmitting ultrasonic waves;
62 is an ultrasonic receiving sensor, 63 is a transmitting and receiving code, 64 is a transmitting circuit having a phase control circuit, 65 is a receiving circuit, and 66 is a display section.

67 is the ground surface, 68 is the interface, 69 is the ultrasonic wave emitted from the array sensor aiming at a certain point, 70 is the route % where the ultrasonic wave 69 actually travels 71 is the certain point that you originally want to aim at, 72
is the range where the actual ultrasound waves are collected. That is, a plurality of ultrasonic transmitting array sensors 61 are provided facing the object, and each ultrasonic transmitting array sensor 61 is connected to a transmitting circuit 64 having a phase control circuit. Ultrasonic reception sensor 6
2 is provided facing the object, and this ultrasonic receiving sensor 62 is connected to a receiving circuit 65. This receiving circuit 65
In the conventional array sensor technology, which is connected to the display section 66 and to the transmitter circuit 64 having the phase control circuit, the array sensor 61 transmits phase-controlled ultrasonic pulses, thereby transmitting ultrasonic pulses in a certain direction. Alternatively, they adopt a method of emitting supersonic waves toward a single point. but,
As shown in Figure 6, in the case of an object with a complex structure, this method assumes that the inside is uniform and uses ultrasonic waves by controlling the phase, since each layer inside the object has a different density and Young's modulus. Even when transmitted, the ultrasonic waves do not travel straight through the internal layer interface 68, but are bent at a certain angle. Therefore, the ultrasonic waves cannot be transmitted in a targeted direction or toward a single targeted point 71, and are concentrated in a wide range 72, resulting in a disadvantage that the intensity of the received signal is low. As a result, the effect of using the array sensor was not necessarily fully demonstrated.

[Problem to be solved by the invention] The present invention has been made in view of the above circumstances.

A method for detecting objects inside a multilayer structure using an ultrasonic method that can accurately detect objects existing inside a multilayer structure by adding improved hardware and software technology to the ultrasonic method of an array sensor. The purpose is to provide a detection device.

[Means and effects for solving the problem] In order to achieve the above object, the present invention uses an ultrasonic method using an array sensor to transmit ultrasonic waves toward a single point inside by controlling the phase. When receiving reflected waves from inside, we find the frequency distribution of only the reflected waves from one target point, and control the phase of the array sensor so that the half-width of that frequency distribution is minimized. , it is possible to detect objects existing inside a multilayer structure with higher accuracy than before.

[Embodiment] Fig. 1 shows an embodiment of the present invention. In Fig. 1, 1 is an array sensor for transmitting ultrasonic waves, 2 is a sensor for receiving reflected waves, and 3 is a sensor for transmitting and receiving ultrasonic waves. 4 is a transmitting circuit having a phase control circuit that transmits phase-controlled ultrasonic waves from the array sensor, 5 is a receiving circuit, 6 is a display section, and 7 is a reflected wave from the target object in the received waveform. 8 is a phase condition setting circuit that provides a wide range of phase setting conditions; 9 is an ultrasonic wave emitted from the array sensor;
10 is an ultrasonic wave reflected and received by a receiving sensor, 11 is a ground surface, 12 is an interface, and 13 is a point where the ultrasonic waves are concentrated.

A plurality of ultrasonic transmitting array sensors 1 are provided facing an object, and each ultrasonic transmitting array sensor 1 is connected to a transmitting circuit 4 having a phase control circuit. A phase condition setting circuit 8 is connected to the transmitting circuit 4 having this phase control circuit. The ultrasonic reception sensor 2 is provided facing the object, and the ultrasonic reception sensor 2 is connected to a reception circuit 5. The receiving circuit 5 is connected to a display section 6 via a signal processing section 7t which performs frequency analysis and half-width calculation, and is also connected to the transmitting circuit 4 having the phase control circuit.

That is, first, as in the conventional array sensor technology, phase-controlled ultrasonic waves are transmitted from the array sensor 1 toward a target point inside. If the interior has a multilayer structure, the ultrasonic waves do not travel straight at the r- boundary surface 12, but are bent at a certain angle. For this reason, the actual ultrasonic waves are not concentrated at a single target point, and the effect of employing an array sensor is hardly exhibited. At this time, the reflected wave from the target object should be observed on a certain time axis of the received waveform received by the center 2, but the waveform itself does not necessarily reflect enough information from the target object. Not included.

FIG. 1 shows the procedure for solving this problem. First, the phase condition setting circuit 8 provides a wide range of phase setting conditions. For example, for a target where the phase difference between the two individual elements forming the array sensor 1 is expected to be 5 m5ec in real time, the optimum phase difference is 1 phase difference t-4, 0, 4, 1, 4,
2...4.9, 5.0, 5.1...5.9゜6
, 0 ms@c and various phase differences are provided, and a wide range of phase conditions are similarly provided for the other array sensors 1. First, an ultrasonic wave is transmitted under conditions corresponding to a phase difference of 4.0 mse, and the received waveform is taken. Second
Of this received waveform, an example of which is shown in the figure, only the signals near the target point are extracted. The signal processing section 7 performs frequency analysis of this waveform. Example of the result No. 3
The half width W shown in the figure and also shown in FIG. 3 is determined. If this is carried out for all phase conditions, the half width w2 can be determined for each phase condition. Figure 4 shows the half price fF when changing the phase setting conditions! This shows the behavior of AW. In actual measurements, the target point may be the most focused among these conditions. In that case, the received waveform is the largest, so the half-width W is the smallest (point A in Figure 4). Figure 5 shows the result of simply setting the conventional phase condition and the case of using the present invention. Compare and show the results.

(&) is an actual stratum cross section, (b) is a display result using a conventional 7A aided array/s, and (c) is a display result according to the present invention. 51 is the ground surface, 52, 53. Objects inside multilayer structures can be detected with high precision.

[Effects of the Invention] As described above, the phase setting conditions of the array sensor are variously changed, and the frequency of the reflected wave from the target object in the received waveform at that time is analyzed to minimize its half width. By selecting such a phase condition, it is possible to detect an object existing inside a multilayer structure with higher precision than before.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment using the present invention, FIG. 2 is a diagram showing an example of a waveform received by a reception sensor according to the present invention, and FIG. FIG. 4 is a diagram showing an example of the change in half-width when the phase difference according to the present invention is changed, and FIG. 5 is a diagram showing an example of the frequency analysis result of the received signal near the point where 6th diagram showing an example of the display result by the two-sided array sensor and the display result by the present invention.
The figure is a configuration explanatory diagram showing a method for measuring a multilayer structure using a conventional array sensor. 1... Array sensor for ultrasonic transmission, 2... Sensor for ultrasonic reception, 3... Cord for transmission and reception, 4...
Transmission circuit having phase control circuit, 5...Reception circuit M, 6
...Display unit, 7...Signal processing unit (frequency analysis, half width calculation), 8...Phase condition setting circuit, 9...Ultrasonic wave emitted from array sensor, 10...Reflected 11...Ground surface, 12...Interface. 13... Point where ultrasonic waves are concentrated. Time (msec) Figure 2 Received waveform

Claims (2)

[Claims] (1) In the ultrasonic method using an array sensor, when transmitting ultrasonic waves toward one point inside the interior and receiving reflected waves from inside by controlling the phase, only the reflected waves from the target point are transmitted. A method for detecting an internal object in a multilayer structure using an ultrasonic method, characterized by determining a frequency distribution and controlling the phase of an array sensor so that the half width of the frequency distribution is minimized. (2) Provide a wide range of phase setting conditions for a plurality of array sensors for transmitting ultrasonic waves, a transmitting circuit having a phase control circuit for transmitting phase-controlled ultrasonic waves from the array sensor, and a transmitting circuit having this phase control circuit. a phase condition setting circuit, an ultrasonic reception sensor and a receiving circuit that receive reflected waves of the ultrasonic waves transmitted from the array sensor, and a frequency of the reflected wave from the target object in the received waveform from the receiving circuit. Using an ultrasonic method characterized by comprising a signal processing unit that performs analysis and half-width calculation of frequency distribution and minimum value calculation of the half-width, and a display unit that displays the processing results of this signal processing unit. A device for detecting internal objects with a multilayer structure.