JPH0572981B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention detects defects in metal materials, for example,
An object visualization method using ultrasonic non-destructive inspection equipment that can display the defect image in high resolution and in real time, or a synthesis method that uses electromagnetic waves to visualize the situation on the ground surface remotely from the sky. This invention relates to an object imaging method using an aperture radar. [Prior art] The method used in conventional ultrasonic non-destructive testing is to focus the ultrasonic beam and measure the spatial information of a single point on the object to be imaged based on the propagation time from the transmission to reception of the reflected signal. , an ultrasonic transmitter/receiver is sequentially scanned electronically or mechanically, and the object image to be visualized is visualized and displayed as a collection of point information. Although the device itself is simple, the resolution in the scanning direction, that is, the azimuth resolution, depends on the degree of narrowing of the ultrasound beam.
In other words, the spread of the ultrasound beam itself gives lateral resolution, and since the spread of the ultrasound beam is proportional to the distance to the object, the lateral resolution deteriorates in proportion to the distance to the object. It was hot. For this reason, it is not always sufficient to meet the recent demands for quantifying the shape of defects in materials in order to evaluate the soundness and remaining life of structural materials such as welded parts of piping in nuclear power plants, thermal power plants, etc. using fracture mechanics techniques. The current situation is that this is not possible. Ultrasonic non-destructive testing using the synthetic aperture method attempts to eliminate the drawbacks of the pulse echo method mentioned above.
In addition to improving the azimuth resolution, this method has the feature that a constant azimuth resolution can be obtained regardless of the distance to the object to be visualized. This will be explained using FIGS. 6 and 7. In Figure 6, 1
is an ultrasonic transmitter/receiver that has an aperture d and can transmit and receive ultrasonic waves, 2 is an ultrasound beam transmitted from the ultrasonic transmitter/receiver 1 and has a beam spread of θω, and 3 is an object to be imaged; It is treated as an object. 4 is a propagation medium interposed between the ultrasound transceiver 1 and the object to be imaged 3; 5 is a scanning line (plane) of the ultrasound transceiver 1; The center frequency of the transmitted ultrasound from the ultrasound transceiver 1 is f, the speed of sound in the propagation medium 4 is C, and the scanning of the ultrasound transceiver 1 is such that the ultrasound beam 2 can see the imaging target object 3. Let L be the length of the range. If the scanning direction of the ultrasound transmitter/receiver 1 is taken as the x-axis, and the depth direction orthogonal to the x-axis is taken as the z-axis, the imaging target object 3 is located at (Xo, Zo) in the x-z plane, and the ultrasound The transceiver element scans the scanning line 5 while transmitting and receiving ultrasonic waves, and its position is set at (x, o). FIG. 7 shows the received signals of the ultrasonic transmitter/receiver 1 due to reflections from the imaging target object 3 at each scanning point (transmission point) in FIG. 6 with respect to time from transmission.
Here, the time from transmission to reception of the ultrasonic reception signal of the ultrasonic transmitter/receiver 1 at the scanning point (x, o) is t(x), that is, the phase delay is t(x)=2/c√(-) ² + ² ... is given by (1). The phase history given by this equation (1) becomes a hyperbola as shown by the chain double-dashed line in FIG. By coherently (in-phase) adding the received signals received within the range of length L, the signal intensity due to the object reflection that is spatiotemporally dispersed on the hyperbola in FIG. 7 is visualized on the target object 3. This means that the corresponding point can be compressed onto the corresponding point. This means that each scanning point on the scanning line 5 in FIG. This is physically equivalent to irradiating the imaging object 3 with the L ultrasonic transmitter/receiver.
This length L is called a synthetic aperture length, and the method of forming an image of the object 3 to be visualized in this way is called a synthetic aperture method. At this time, the azimuth resolution δ _x is given by the ultrasound wavelength λ as δ _x = λ/LZo (2), where L is the spread of the ultrasound beam λ/d and the distance Zo to the imaging target object 3. Given L=λ/dZo...(3), so substituting L determined by equation (3) into equation (2),
In the end, the azimuth resolution becomes δ _x = d...(4). As can be seen from equation (4), the azimuth resolution by the above synthetic aperture method is the distance Zo to the imaging target object 3.
It is constant at approximately the aperture d of the ultrasonic transmitter/receiver 1, without depending on . For example, the object imaging method using the synthetic aperture method is
A case in which the process is performed on the xz plane in the figure will be explained using FIG. 8. In FIG. 8, the area reproduced using the received signal group at all scanning points within the range of the synthetic aperture length L is each point on the imaging target line segment l of the center line of the synthetic aperture length L,
The received signal group necessary to reproduce the imaging target point l _K on the imaging target line segment l is the value of the received signal on the hyperbola indicated by the two-dot chain line in the figure. At this time, the synthetic aperture length L is z to be imaged on the x-z plane.
It is defined corresponding to the position with the greatest distance in the direction. Further, the range in which the hyperbola is defined is determined by the spread of the ultrasonic beam of the ultrasonic transmitter/receiver, and is indicated by a dotted line. In other words, in order to image an area with a synthetic aperture length L in the scanning direction, a group of received signals from all scanning points in a scanning range of 2L, which is twice the synthetic aperture length, is required. be. In the figure, the received signal group necessary to image the imaging area AR1 having a width L in the x-axis direction is that the entire receiving signal group in the scanning range SC1 having a length of 2L is the same as that in the imaging area AR2 having a width L. As for the received signal group necessary for imaging, the entire received signal group of the scanning range SC2 having a length of 2L becomes necessary. When attempting to image a wide range of imaging areas using this method, the phase history line indicated by the hyperbola for image reproduction has different values in the z-axis direction (direction perpendicular to the scanning direction). Since the shapes of these functions differ for each point, the received signal string at each scanning point is A/D converted and stored in memory, and all the received signal strings for each scanning point are converted in one direction to the scanning point. The received signal at each scanning point determined from the phase history line corresponding to the point to be imaged is captured into a two-dimensional memory consisting of a two-dimensional configuration in which one direction corresponds to time, that is, distance in the z-axis direction. It is necessary to sequentially pick up and add up the signal values in the column. This processing operation will be repeatedly executed for all the imaging target points. [Problems to be solved by the invention] Since the conventional object imaging method using ultrasonic waves or electromagnetic waves is configured as described above, the imaging area must be updated sequentially and a wide range of areas must be imaged. In the case of non-destructive inspection of piping, etc., unless considerable effort is made to store the received signal sequences of scanning points and process for image reproduction, large-capacity memory to store the huge number of received signal groups will be required. This requires an extremely long image reproduction processing time, and the image reproduction results are affected by the spatial propagation characteristics of ultrasound or electromagnetic waves, that is, the beam spread characteristics, attenuation due to propagation distance, etc. There were problems in that physical information such as the scattering coefficient of the target object could not be appropriately obtained without some kind of correction. This invention was made to solve the above-mentioned problems, and it is possible to reduce memory requirements and speed up image reproduction processing time in an object imaging method using ultrasonic waves or electromagnetic waves using the synthetic aperture method. The purpose of the present invention is to obtain a method for imaging objects using ultrasonic waves or electromagnetic waves, which can realize real-time processing and obtain high-quality images. [Means for Solving the Problems] A method for imaging an object using ultrasound or electromagnetic waves according to the present invention receives a reflected wave of an ultrasound or electromagnetic wave beam from a target object, and processes the received signal from transmission to reception. In an object imaging method based on the synthetic aperture method that obtains a target object image using a phase history line along the scanning direction determined by the phase delay, the discrete digital values obtained by converting the received signal sequence at each scanning point from analog to digital are converted into 1 When sequentially storing a group of received signals within the synthetic aperture range into a waveform memory, the data in the waveform memory section is line-shifted one scan at a time, and one synthetic aperture range is always created with the latest scanning point as the end point. The received signal groups within the range are stored in the waveform memory section, each data group in the waveform memory section is read out using each address information group corresponding to each phase history line, and the data is accumulated for each data group. Obtain data for a line image of the center line of the synthetic aperture range with the latest scanning point as the end point, and add data to this line image data based on the direct distance from the scanning line (plane) of the ultrasonic or electromagnetic wave transmission/reception system. The image is corrected by being multiplied by a determined image correction value, and the corrected line image data is obtained one after another as described above and visualized. [Operation] The object imaging method using ultrasonic waves or electromagnetic waves according to the present invention is that when storing the discrete digital values obtained by converting the received signal sequence at each scanning point into analog/digital values in the waveform memory section, The received signal group up to the scanning point immediately before the latest scanning point is line-shifted by one scanning point, and the reception signal group corresponding to the latest scanning point is transferred to the area where the received signal sequence corresponding to the immediately preceding scanning point was stored. 1. Store the signal sequence and set the latest scanning point in the waveform memory section as the termination point.
The received signal groups obtained from the synthetic aperture range are stored in a matrix, each data group in the waveform memory section is read out using each address information group corresponding to each phase history line, and each data group is accumulated. 1 Obtain line image data corresponding to the center line of the synthetic aperture range, and multiply the line image data by an image correction value determined by the direct distance from the scanning line (plane) of the ultrasound or electromagnetic wave transmission/reception system. This corrected line image data is obtained for each transmission and reception of ultrasound or electromagnetic waves at each scanning point and sequentially visualized. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings. First, in order to make the embodiment of the present invention easier to understand, the principle of the embodiment of the present invention will be explained. 1 In order to image the imaging target line segment l of the center line within the synthesis range, the phase history lines corresponding to each pixel to output data of each pixel constituting the line image of the imaging target line segment l are mutually They are different. However, the functional forms of these phase history lines in one synthetic aperture range are the same as the functional forms of the phase history lines in another synthetic aperture range, respectively. In other words, each phase history line for each received signal group within each synthetic aperture range for reproducing an image of each line segment to be visualized in the direction directly below the scanning point (for example, the z direction in FIG. 6) is used to reproduce the image. We focused on the fact that the received signal groups within each synthetic aperture range corresponding to each line segment to be imaged can be used in common even if the synthetic aperture ranges are at different positions. The phase history line is used for image data processing. The synthetic aperture range here is defined as the range that corresponds to the farthest distance from the scanning point from which an image is to be reproduced. This will be explained using FIG. 5. In FIG. 5, when reproducing the image of the line segment l1 to be imaged, which is the center line of the synthetic aperture range SA1, the phase history line table section PT shown in the figure is used for the received signal group of the synthetic aperture range SA1. Using the address information of the phase history line PL, it is possible to sequentially reproduce the imaging target points on the imaging target line segment l1. For example, the phase history table section PT stores a group of address information regarding a hyperbolic phase history line PL of a line segment l to be imaged with each imaging target point as its apex. Let l1 be the line segment to be imaged for the synthetic aperture range SA1, and one point _l1K to be imaged on this line segment to be imaged l1. Let l _K be the imaging symmetric point on the imaging target line segment l corresponding to this l1 _K , and let the phase history line PL _K for this point l _K be the phase history line PL _K
The address information for the phase history line table PT
The address information of the received signal group within the synthetic aperture range SA1, that is, the phase history line PL _K
The above received signals are taken out from the waveform memory section, which will be described later, and added to generate uncorrected data of one pixel corresponding to the imaging target point _l1K . If this is done for all the imaging target points of the imaging target line segment l1, one line of uncorrected data for the line image for imaging the imaging target line segment l1 can be obtained. . Next, the synthetic aperture range SA1 is one scan.
When imaging the imaging target line segment l2 for the synthetic aperture range SA2 shifted by P', the received signal group of the common range CA that is common to the synthetic aperture range SA1 and the synthetic aperture range SA2 is the line of the imaging target line segment l2. It is also commonly used when calculating image data. Therefore, the received signal group for this range CA is the imaging target line segment l1
The data for the line image before correction is also left after calculation. Scanning point SCP2 is applied to such a group of received signals.
Add the received signal train obtained by scanning with
As in the case of SA1, the received signal group for the synthetic aperture range SA2 is processed to obtain uncorrected line image data for the line segment l2 to be imaged. Here, the imaging target point on the imaging target line segment l2
If l2 _K corresponds to point l _K on the line segment l to be imaged, address information regarding the same phase history line PL _K as point l1 _K can be used in common. In this way, the address information regarding the phase history line PL stored in the phase history line table section PT can be used in common to obtain data for each line image for each received signal group in each synthetic aperture range. . By sequentially repeating the above processing operations and correcting the line image data each time as described below, a two-dimensional image will be successively reproduced as a collection of line images. At this time, for example, in the received signal group of the synthetic aperture range SA1 and the synthetic aperture range SA2, the received signal sequence of the leftmost scanning point SCP1 of the synthetic aperture range SA1 and the rightmost scanning point SCP2 of the synthetic aperture range SA2 shown in FIG. Note that the received signal groups of only the common range CA are exactly the same, with the only difference being that. That is, it has a two-dimensional storage memory (hereinafter referred to as a waveform memory unit) that can store a group of received signals for one synthetic aperture range, and sequentially scans the ultrasonic transceiver.
After transmitting and receiving ultrasonic waves and performing analog/digital conversion (hereinafter referred to as A/D conversion) of the received signal,
When storing in the waveform memory section, all received signal groups in the waveform memory section are line-shifted by one scan, and the received signal sequence corresponding to the scanning point immediately before the latest scanning point to be stored is shifted by one line. This received signal string is stored in the stored column after line shifting. Next, the phase history line table section PT
Regenerate the line image data using , output and display it,
It can be seen that it is sufficient to sequentially repeat the processing operation of moving to the next scanning point. In addition, before outputting and displaying the line image, by performing correction based on the ultrasound propagation characteristics for each imaging target point of the line image, which is the imaging target line segment l, the ultrasound propagation distance, ultrasound beam spread, etc. It is possible to output and display a reproduced image from which the influence of At this time, correction of the reproduced image can be performed by multiplying the line image data of each imaging target point on the line image by a correction value for that point, and this correction value is further applied to each image on the line image. If the correction values for the points to be converted are made into a table, they can be used commonly for all line images. It should be noted that when processing the above received signal group, it has been explained that the received signal group corresponding to one synthetic aperture range is stored in the waveform memory section, but even if the waveform memory section has a larger capacity. good. FIG. 1 is a block diagram of an apparatus to which an embodiment of the present invention is applied. In the figure, 1 is an ultrasonic transmitter/receiver that has an aperture d and is capable of transmitting an ultrasonic beam having a spread angle θω and receives the echo; 6 is a material to be inspected; The purpose is to image the inside of the material 6 to be inspected and visualize internal defects. 7 is ultrasonic transmitter/receiver 1
8 is a pulse generator for applying a spike-like pulse voltage to transmit an ultrasonic signal into the test material 6; 8 is for amplifying the harmonic reception signal obtained by the ultrasonic transceiver 1; The reception amplifier 9 is an A/D converter, which A/D converts the reception signal amplified to a predetermined level by the reception amplifier 8, obtains a digital value, and converts the continuous signal at a predetermined sampling time. Discretize. Reference numeral 10 denotes a transmission/reception timing controller, which generates a timing signal for applying a pulse voltage from the pulse generator 7 to the ultrasonic receiver 1, and also controls the start time for the A/D converter 9 to A/D convert the received signal. Generates timing signals to control. 11 provides a control signal for generating a timing signal to the transmission/reception timing controller 10, and also generates a control signal for causing the ultrasonic transceiver 1 to scan the surface of the specimen 6; 1 is a measurement system control unit that controls the timing of capturing position information during ultrasound transmission and reception via the scan drive unit encoder of the ultrasound transceiver 1; This is a scanning drive unit for causing the child 1 to scan. 13 is a waveform memory section for storing the received signal sequence at each scanning point converted into discrete digital values by the A/D converter 9 while sequentially line-shifting the entire area data; 14 is the aforementioned waveform memory section; This is a phase history line table section for reproducing images of each point on the imaging target line l from a group of received signals within the synthetic aperture range, and the phase history line table section 14 reproduces images of each point on the imaging target line l as described later. A group of address information for reading out corresponding values in the received signal sequence corresponding to each scanning point from the waveform memory unit 13 is written in accordance with each phase history line necessary for image reproduction of the imaging target point. It is also an address table. Reference numeral 15 denotes a correction value table section for correcting the reproduced image corresponding to each point on the line to be imaged, and as described later, this correction value is
A correction value determined only by the z coordinate value in the figure is calculated and stored in advance. Reference numeral 16 denotes an image reproduction control section, in which the discrete digital values obtained by the A/D converter 9 are written into the waveform memory according to the T address and address information of the phase history line table section 14 for writing into the waveform memory section 13. Part 1
(i, J) address for reading the value from 3,
The values in the waveform memory section 13 are read out sequentially or in parallel along the phase history line, and the result of addition or accumulation of the read values corresponds to the number of the imaging target point on the imaging target line l. A signal for reading a correction value from the correction value table 15 is generated under control in synchronization with the k address to perform image correction on the addition result, which is the reproduced image value. 17 is an image playback control section 16
An accumulator 18 is a multiplier for adding or accumulating the values read out from the waveform memory unit 13 in accordance with the (i, J) address signal from the image reproduction control unit 16. The correction value for correcting the reproduced image read from the correction value table section 15 in accordance with the k address signal which is the target point information is multiplied by the accumulation result which is the output of the accumulator 17. Reference numeral 19 denotes an image memory unit into which corrected image reproduction values, which are the outputs of the multiplier 18, are sequentially written in accordance with the k address signal from the image reproduction control unit 16, and the reproduced image of the line to be imaged is stored; and 20, an image display unit. The two-dimensional image is displayed in such a way that the image area is continuously updated by displaying the reproduced image values in the image memory section 19 while sequentially line-shifting (scrolling) them. 2 to 4 show the configurations of the waveform memory section 13, phase history line table section 14, and correction value table section 15 shown in FIG. 1 when the test material 6 is in the shape of a circular pipe. be. The configuration of the waveform memory section 13 and phase history line table section 14 shown in FIG. 1 will be described below with reference to FIG. 2 in the case where the specimen 6 is in the shape of a circular pipe. In the figure, the outer radius of the pipe from the pipe center O to the pipe outer wall T0 is Ro, and the pipe inner radius from the pipe center O to the pipe inner wall T1 is Ri. Assume that the surface is being scanned in the circumferential direction. The aperture of the ultrasonic transmitter/receiver 1 being scanned is d, the speed of sound in the piping material is c, the center frequency of the transmitted ultrasonic wave is f, and one point on the inner wall T1 of the piping is the piping where the ultrasonic beam can be expected. If the synthetic aperture length on the outer wall T0 surface is L, the angle at the pipe center O looking into this synthetic aperture length L is α, and the spread angle of the ultrasonic beam of the ultrasonic transmitter/receiver 1 is θω, then the ultrasonic wavelength λ is λ =c/f...(5), and the spread angle θω of the ultrasonic beam is θ=λ/d...(6). The synthetic aperture length L is calculated using the angle α as L=Ro・α (7), and in this case α is

It is given by [ ]. Next, consider a scanning point Q (for example, Qi) on the pipe outer wall surface that corresponds to the pipe center angle θ (for example, θi) from the line segment l to be imaged. In the figure, the depth Zo on the line segment l to be imaged (Z _OK when the variable K is specified as one value) is the position of one value of Zo up to the image target point _lK at this scanning point Q (for example, Qi ) is the expected distance from Z (if the variable K is specified as one value, Z _K is the scanning point Qi, and the imaging target point is l _K , then 1 of Z)
Z=√ ² (−) ² −2(−)

......(9), the angle θ ^max _ZO between the scanning point located at the farthest point that the ultrasonic beam can expect from a point with a distance Zo and the line segment l to be imaged as the reference line at the piping center point O is It is limited by the sound wave beam spread angle θω and is given by the following equation.

[C] Therefore, the possible range of the angle θ _ZO with the line segment l to be imaged at the scanning point piping center O at the scanning point where the ultrasonic beam can be expected to reach the point of depth Zo as the reference line is |θ _ZO | lθ ^max _ZO is given by (11). Piping inner wall TI with line segment l to be imaged
The scanning point on the surface where the ultrasonic beam can be expected, that is, the outer wall of the pipe with a synthetic opening length L, indicated by L in the figure.
The distance Z ^max between the scan points at both ends on the T0 plane and that point on the TI plane of the pipe inner wall If the received signal train must include the ultrasonic signal propagating _ZO=RO-Ri, the line to be imaged in the figure All points in the division l will not be reproduced as images.
Z ^max _ZO=RO-Ri is given by the following formula.

[ ] Therefore, the capacity (M
×N frame memory configuration), the number of rows M corresponds to the angular pitch of the scanning pitch of the ultrasonic transmitter/receiver 1 at the piping center O. Using Δθ, M = [L/Ro・Δθ] Gauss symbol + 1... ...(13), and the number of columns N is the A/D of the ultrasonic reception signal.
Assuming the sampling time during conversion as Δt _R , N=[2・Z ^max / _ZO=RO-Ri /C・Δt _R +0.5
] Gauss sign + 1...(14) is given. However, [ ] Gauss symbol is
[ ] Indicates an operator that converts the value in parentheses into an integer. Here, when reproducing the image of the Kth imaging target point l _K at depth Z _OK on the imaging target line segment l, the ultrasonic reception signal group of the waveform memory section 13 in FIG. 1 is as follows. The peak values of addresses (i, J) are read out and added, and the K-th pre-correction reproduced image value is obtained. It is sufficient here to describe how to obtain the J address corresponding to the i-th row of received signal sequences in the waveform memory section 13 of FIG. The depth Z _OK of the K-th imaging symmetric point l _K on the line segment l to be imaged is given by Z _OK = 1/2 (K-1) C・Δt _R ...(15), and the i-th line The second angle, which is the angle between the scanning point Qi and the line segment l to be imaged, corresponding to the received signal sequence of
The angle θi in the figure becomes θi=(M+1/2−i)Δθ (16) using the number of rows M determined by equation (13) of the waveform memory unit 13 in FIG. The distance between this operating point Qi and the imaging target point l _K
Z _K is given by the following equation using Z _OK and θi in equations (15) and (16). Z _K = √ ² + (+ _OK ) ² −2 (
- _OK )...(17) The column address J of the value to be read from the i-th received signal string of the waveform memory unit 13 for the above distance Z _K is J = [2・Z _K /C・Δt _R +0.5] Gauss sign +1...(
18) is given by However, here, the range of scanning points _Qi that can be defined in the waveform memory unit 13, that is, the range of row addresses i, with respect to the imaging target point lK is
i ^min determined by the following equation from equations (10), (11), (15), and (16)
_K ~
It is specified that it can take the value i ^max _K.

〔Effect of the invention〕

As described above, according to the present invention, in the object imaging method based on the synthetic aperture method with excellent lateral resolution, an ultrasound or electromagnetic wave beam is irradiated onto the imaging exercise object, and reflected waves from the object to be visualized are received. Then, the received signal group for one synthetic aperture range is stored in the waveform memory section, and data is accumulated for each data group using each data group in the waveform memory section corresponding to each phase history line, and the data for the synthetic aperture range is calculated. Output the data for the line image of the center line, and convert this data for the line image to the scanning line (area)
It is configured to perform correction using an image correction value determined by the direct distance from the line image, display the corrected line image data sequentially, and visualize the spatial area to be imaged while scanning the ultrasound or electromagnetic wave transmitting/receiving system. Therefore, it is possible to save the necessary memory capacity and make effective use of the limited memory area, and at the same time, it is possible to realize faster image playback processing time (real time).
Furthermore, there is an effect that high-quality image reproduction can be realized regardless of distance.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram for explaining in more detail one embodiment of the object imaging method of the present invention, and FIG. 2 is a diagram for explaining the waveform memory section and phase history table section shown in FIG. 1. , FIG. 3 is an explanatory diagram for explaining the correction value table section in FIG. 1, and FIG. 4 is a phase history line in FIG. 1 for an embodiment of the object imaging method according to another invention of the present invention. FIG. 5 is a diagram for explaining the relationship between the table section and the waveform memory section, FIG. 5 is a diagram for explaining the object imaging method according to the present invention, and FIG. 6 is a diagram for explaining the object image reproduction method based on the conventional synthetic aperture method. FIG. 7 is a diagram for explaining the received signal when the ultrasonic transmitter/receiver in FIG. 1 receives the ultrasonic received signal reflected by the imaging object point along the scanning line (plane) A diagram showing the phase history from transmission to reception. Figure 8 shows the imaging area (line to be imaged) in the object imaging method based on the synthetic aperture method, the ultrasonic reception signal group necessary for image reproduction, and its reception. FIG. 3 is a diagram for explaining the required scanning range of an ultrasonic transmitter/receiver necessary to obtain a signal group. 1 is an ultrasonic transceiver, 2 is an ultrasonic beam, 5 is a scanning line (surface), 6 is a material to be inspected, 7 is a pulse generator,
8 is a reception amplifier, 9 is an A/D converter, 10 is a transmission/reception timing controller, 11 is a measuring meter control section, 12 is a scanning drive section, 13 is a waveform memory section, 14 is a phase history line table section, and 15 is a correction section. Value table section, 16
17 is an accumulator, 18 is a multiplier, 19 is an image memory section, and 20 is an image display section. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. When visualizing an image of a target object using ultrasonic waves or electromagnetic waves, the ultrasonic wave or electromagnetic wave transmitting/receiving system is mechanically or electronically scanned and the target object is spatially spread. A beam of turbulent ultrasound or electromagnetic waves is irradiated, a reflected wave from the target object is received, and an image of the target object is created using a phase history line along the scanning direction determined by the phase delay between the transmission and reception of the received signal. In an object imaging method using ultrasound or electromagnetic waves based on a synthetic aperture method, while scanning the ultrasound or electromagnetic wave transmission/reception system,
When storing the discrete digital values obtained by analog/digital conversion of the received signal sequence at each scanning point in the waveform memory section consisting of a two-dimensional frame memory configuration corresponding to the scanning points only within one synthetic aperture range, the All the received signal train groups in the waveform memory section up to the scanning point immediately before the latest scanning point are line-shifted by one scanning point, and are transferred to the area where the received signal train corresponding to the most recent scanning point was stored. Storing the received signal string corresponding to the latest scanning point, and accumulating data for each data group using each data group in the waveform memory section read out by each address information group corresponding to each phase history line. and output data for a line image of the center line of the synthetic aperture range with the latest scanning point as the end point, and include the scanning line of the ultrasonic or electromagnetic wave transmitting/receiving system or directly below the scanning plane in the data for the line image. The image correction value determined by the distance is multiplied and corrected, and the corrected line image data of the center line of the synthetic aperture range is sequentially displayed as an image, and the spatial region to be imaged of the target object is A method for imaging an object using ultrasound or electromagnetic waves, which is characterized by imaging an ultrasound or electromagnetic wave transmission/reception system while scanning it. 2. Calculate in advance the image correction value determined from the direct distance corresponding to each imaging target point on the center line of the synthetic aperture range from the scanning line or the scanning plane, create a table, and store it in a one-dimensional line memory. . The method for imaging an object using ultrasound or electromagnetic waves according to claim 1, characterized in that each of the image correction values is read out from the line memory in correspondence with each of the image target points and multiplied.