JPS6279368A - Processing of waveform signal to be displayed on crt - Google Patents

Abstract

PURPOSE:To analyze a waveform signal at a high speed, by a method wherein the waveform signal is picked up with a TV camera, the video signal is converted into digital from analog while being transmitted to an image input/ output unit to store into an image memory and the data being stored is computed through a signal processor. CONSTITUTION:A detector 2 transmits or receives an ultrasonic wave with a probe 1 and amplifies a sound pressure signal of the waveform received to be displayed on a CRT of (A) scope display. The waveform displayed is picked up with a TV camera 3 and the video signal is transmitted to an image input/ output unit 4, which converts the video signal transmitted into digital from analog to memorize a signal level into an image memory. The data stored is transferred to a signal processor 5 for computation. Thus, the waveform signal can be analyzed at a high speed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a processing method for analyzing waveform signals displayed on a CRT, and in particular to automatically inspecting defects in a member using ultrasonic waves. The present invention relates to a processing method suitable for automatic ultrasonic flaw detection and analysis of high-frequency signals emitted in repeated cycles.

[Background of the invention]

There is a need to detect internal defects in so-called thin materials, such as those with a thickness of 1 piece or less, as well as defects near the surface and minute internal defects of fragile materials such as ceramics. In recent years, it has become increasingly important in various technical fields to ensure the high quality of industrial materials. Conventionally, such a request has been met by using a high frequency probe and its flaw detection device due to the wavelength. An example of automatic ultrasonic flaw detection will be explained with reference to FIG. A probe 1 is generally immersed in a liquid in a liquid tank, emits ultrasonic waves to a subject in the liquid tank, and receives reflected waves reflected from the subject. 2' is a flaw detector connected to probe 1 by a high-frequency cable, which causes probe 1 to transmit and receive the ultrasonic waves, amplifies the received waveform sound pressure signal, and displays it on the CRT displayed on the A scope. to be displayed. The flaw detector 2' is the CRT
and sends the signal to the digitizer 6. The digitizer 6 A/D converts the sent signals, stores them in memory, and then transfers the data to the signal processing device 5. The signal processing device 5 inputs signals to determine the presence or absence of a defect in the object to be inspected, and the shape and position of the object.

It has built-in software that judges dimensions, etc., and has functions such as displaying the judgment results on the display device in the signal processing device 5, and issuing a warning and notifying the inspector if the judgment criteria are not passed. There is. When such an automatic ultrasonic flaw detector uses a high frequency to inspect the above-mentioned minute defects, the number of measurement points increases and the number of signals increases, so it is necessary to shorten the A/D conversion time of the digitizer 6. Since the amount of data also increases, the time required for transfer from the digitizer 6 to the signal processing device 5 also increases.

Increasing the A/D conversion time has the problem that not only the digitizer 6 but also other devices become expensive, and this problem becomes more severe as the frequency becomes higher.

Next, an example of a method for processing a waveform signal displayed on a CRT of an oscilloscope using a high frequency signal emitted in a repetitive period will be explained with reference to FIGS. 4 and 5. FIG. 4 is a diagram showing one pattern of a waveform displayed on the CRT of an oscilloscope. The horizontal axis is divided into equally spaced corners, and the points on the divided waveform, that is, the measurement points are sequentially a, b, c, . . .・・・
...g.

When the waveform level at each measurement point is A/D converted by the digitizer 6 and stored in the memory, the result shown in FIG. 5 is obtained. In this case, the storage in the memory is carried out by the so-called equivalent sampling method in which one point is taken in each repetition period, and the digitizer 6 must operate for each measurement point and take in the number N of measurement points.

For example, if N is 100, the digitizer 6 operates 100 times. By the way, when a high frequency signal with a repetition period of 5 KHz is processed using the equivalent sampling method described above, N is 1.
, 000, the time required to complete storage in the memory is approximately 0.2 to 0.3 seconds. Considering that the same amount of time is required to process many other waveform signals that appear subsequently, it will take a considerable amount of time to test a single object, and if the number of measurement points N is increased, The time required will increase proportionally. This poses a major problem in terms of work efficiency when a large number of subjects are automatically and continuously processed.

[Object of the Invention] The present invention solves the problems of the prior art described above, and analyzes waveform signals displayed on a CRT easily and at extremely high speed, at low cost, without being affected by an increase in the number of measurement points. The purpose is to provide a processing method that can.

[Summary of the invention]

The present invention provides a waveform signal processing method in which a waveform signal displayed on a CRT is A/D converted, and the A/D converted signal is processed through a signal processing device. and convert the video signal into an A/D
By transmitting the data to an image input/output device that converts and stores it in an image memory, and arithmetic processing the stored data through the signal processing device, the waveform signal displayed on the CRT is This is a processing method that allows for extremely high-speed, low-cost, and easy analysis without undergoing any processing.

[Embodiments of the invention]

Embodiments of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, the same reference numerals as in FIG. 3 indicate the same thing.

1 is a probe, and 2 is a flaw detector.

Unlike the flaw detector 2' shown in FIG. 3, which is connected to the digitizer 6, the flaw detector 2 has the probe 1 transmit and receive ultrasonic waves, and amplifies the received waveform sound pressure signal. It is only necessary to display it on a CRT with an A-1 display. The displayed waveform is photographed by a television camera 3, and the video signal is transmitted to an image input/output device 4. The image input/output device 4 A/D converts the transmitted video signal and records the signal level in the image memory. The recorded data is sent to the signal processing device 5.
is transferred to and processed.

The data stored in the image memory is stored in the television camera 3.
Since the video signal is A/D converted from a video signal taken by can be imported in its entirety. Since the captured waveform is a video signal, the position data on the coordinates of the waveform is already the memory address itself, and signal processing can be performed simply by finding an address where the video brightness level is above a certain value. In addition, in the prior art, the waveform is loaded into the memory at each measurement point on the waveform, and as the number of measurement points increases, the A/D conversion time of the digitizer increases proportionally, but in the method of the present invention, the CR
Since it is performed for each screen on T, the A/D of the waveform signal is completely unaffected by the number of measurement points for that screen.
The conversion time is constant and unchanged for each changing screen.

Therefore, the processing speed is increased by about one order of magnitude compared to the conventional processing method, and this difference becomes larger as the number of measurement points increases. Although this embodiment has been described in the case of ultrasonic flaw detection, it goes without saying that it can be similarly applied to the case of high frequency signals emitted at the above-mentioned repetition period.

Next, when the brightness level of the video is A/D converted, 1
An example is shown in FIG. The numbers in the figure indicate A/D conversion values corresponding to the waveform in FIG. 4, where 30 indicates the brightness level of the screen, and 150 indicates the measurement points a and b of the waveform.

. . . is a value indicating the luminance level of g. Since the waveform data is stored in the image memory in this state,
For example, when detecting the peak value of a waveform, it is sufficient to search for addresses with a brightness level of 150 for each row from the first row, and detect the one at the address closest to the first row. When detecting an interval, search for an address with a brightness level of 150 in each row from the first row, and also search in each column from the first column. It is sufficient to detect the object at the address. This search can be performed extremely easily and at high speed, and the same processing as that of the conventional expensive digitizer can be performed with an inexpensive combination of the television camera 3 and the image input/output device 4.

〔Effect of the invention〕

As explained above, the method of the present invention is a method for processing a waveform signal displayed on a CRT. Since the data is transmitted to the output device and the stored data is processed through the signal processing device, the waveform signal displayed on the CRT can be processed at extremely high speed without being affected by the increase in the number of measurement points. It has an excellent effect that it can be analyzed easily and at low cost.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the present invention in detail, and FIG. 2 is a diagram showing A/D conversion values of the brightness level of an image taken by a television camera. Figure 3 is a diagram explaining a waveform signal processing method in conventional automatic ultrasonic flaw detection, Figure 4 is a diagram showing one pattern of waveforms displayed on the CRT of an oscilloscope, and Figure 5 is a diagram explaining the waveform signal processing method in conventional automatic ultrasonic flaw detection.
It is a figure which shows the memory storage value which A/D-converted each measurement point on the waveform shown in the figure by the digitizer. DESCRIPTION OF SYMBOLS 1... Probe, 2, 2'... Flaw detector, 3... Television camera, 4... Image input/output device, 5... Signal processing device, 6... Digitizer. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. The waveform signal displayed on the CRT is A/D converted,
In the waveform signal processing method, the A/D-converted signal is subjected to arithmetic processing via a signal processing device, in which the waveform signal is photographed with a television camera, the video signal is A/D-converted, and stored in an image memory. image input/output device,
A method for processing a waveform signal displayed on a CRT, characterized in that the stored data is subjected to arithmetic processing via the signal processing device.