JPH0573173B2 - - 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 was scanned electronically or mechanically in sequence, and the image of the object to be visualized was visualized and displayed as a collection of point information. The device using this method is simple, but the resolution in the scanning direction, that is, the azimuth resolution, depends on the degree of narrowing down of the ultrasound beam; in other words, the spread of the ultrasound beam itself gives the azimuth resolution. Since the spread of the ultrasonic beam is proportional to the distance to the object, the lateral resolution deteriorates in proportion to the distance to the object. For this reason, there is a demand 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, especially in recent years.
The current situation is that it is not always possible to adequately respond. 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 FIG. 5 and FIG. 6. In Figure 5,
1 is an ultrasonic transmitter/receiver that has an aperture d and can transmit and receive ultrasound; 2 is an ultrasound beam transmitted from the ultrasonic transmitter/receiver 1 and has a beam divergence angle θ; 3 is an object to be visualized; Here, it is assumed to be a point 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 transmitter/receiver 1 is the speed of sound in the propagation medium 4, and the scanning range of the ultrasound transmitter/receiver 1 in which the ultrasound beam 2 can see the object 3 to be visualized. The length of is L. If the scanning direction of the ultrasound transmitter/receiver 1 is taken as the x-axis, and the depth direction perpendicular to the x-axis is taken as the z-axis, the imaging target object 3 is located at (X _p , Z _p ) in the x-z plane, The ultrasonic transceiver 1 scans the scanning line 5 while transmitting and receiving ultrasonic waves, and its position is set at (x, o). FIG. 6 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. 5 with respect to the time from transmission. Here, the time t(x) from transmission to reception of the ultrasonic reception signal of the ultrasonic transceiver 1 at the scanning point (x, o) is t(x)=2/c√( _-p ) ² + ² _p ……(1) is given. The round trip propagation time trajectory 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 object reflections that are spatiotemporally dispersed on the hyperbola in Fig. 6 is determined from the object to be visualized. 3
The image can be reproduced on the corresponding object 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 an ultrasonic transceiver having an aperture of length L. 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 the ultrasonic waveform λ, and δ _x = λ/L・Z _p ...(2) where L is the spread of the ultrasonic beam 2 λ/d and the object to be imaged 3 It is given by _the distance Z _p to
In the end, the azimuth resolution is δ _x = d (4). As can be seen from equation (4), the azimuth resolution according to the synthetic aperture method does not depend on the distance Z _p to the object 3 to be imaged, but becomes constant with the aperture d of the ultrasound transmitter/receiver 1 . A case where the object imaging method using the synthetic aperture method is applied to, for example, the xz plane in FIG. 5 will be explained using FIG. 7. In FIG. 7, 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 FIG. The synthetic aperture length L at this time is defined corresponding to the position with the greatest distance in the z-axis direction to be imaged on the xz plane. Further, the range in which the hyperbola is defined is determined by the spread of the ultrasonic beam 2 of the ultrasonic transmitter/receiver 1, and is shown by the dotted line in the middle of FIG.
That is, in order to image an area with a length of synthetic aperture length L in the scanning direction, 2 of the synthetic aperture length L must be
This means that a group of received signals from all scanning points in a scanning range of 2L is required. In Fig. 7, the received signal group necessary to image the imaging area AR1 having a width L in the x-axis direction is such that the entire received signal group in the scanning range SC1 having a length of 2L is the same as the imaging area having a width L. As for the received signal group necessary to image AR2, 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 round trip propagation time locus shown by the hyperbola for image reproduction has different values in the z-axis direction (direction perpendicular to the x-axis in the scanning direction). Since the shapes of these functions are different for the reproduction target point with ,
Once the received signal string at each scanning point is A/D converted and stored in memory, one direction corresponds to the scanning point and one direction corresponds to time, that is, the z-axis direction. The signal value in the received signal train at each scanning point determined from the round trip propagation time trajectory corresponding to the object point to be imaged is sequentially picked up. You need to add it up. This processing operation is repeatedly executed for all 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 sections, etc., where there is no damage, considerable effort must be taken in the storage of the received signal sequence at the scanning point and the processing for image reproduction. This requires memory and an extremely long image reproduction processing time, and the image reproduction result is subject to the spatial propagation characteristics of ultrasound or electromagnetic waves, that is, beam spread characteristics, attenuation due to propagation distance, etc. However, there were problems in that it was not possible to appropriately obtain physical information such as the scattering coefficient of the target object without some kind of correction. This invention was made to solve the above-mentioned problems, and it is possible to save memory capacity 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 achieve 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, which obtains an image of a target object using a round-trip propagation time trajectory along the scanning direction determined by the round-trip propagation time, a discrete digital signal is obtained by converting the received signal sequence at each scanning point from analog to digital. When sequentially storing values in the waveform memory section that stores received signal groups within one synthetic aperture range, the address information of the waveform memory section corresponding to each round trip propagation time trajectory is stored in the focus table section. The data is line-shifted annularly by one scanning point at a time, and the data for the line image of the center line of the synthetic aperture range is displayed sequentially, with the latest scanning point as the terminal point. The area is visualized while being scanned by ultrasound or electromagnetic wave transmission/reception system. [Operation] The object imaging method using ultrasonic waves or electromagnetic waves according to the present invention is such that when discrete digital values obtained by converting a received signal sequence at each scanning point into analog/digital values are sequentially stored in the waveform memory section, the waveform memory The storage line of the section is updated in a circular manner. At this time, all address data groups are stored in the focus table section which stores address data for reading data from the waveform memory section corresponding to each round trip propagation time locus in order to reproduce the image of the center line of one synthetic aperture range. The waveform is shifted circularly by one scanning point at a time, so that the center line of one synthetic aperture range with the latest scanning point as the terminal point can always be used for image reconstruction for the received signal group in the waveform memory section. Each memory line of the data in the memory section and the data in the focus table section are made to correspond to each other, and each data group corresponding to each round trip propagation time trajectory is extracted from the waveform memory section according to the address data of the focus table section. The data for the line image of the center line of the synthetic aperture range is read out and added for each data group, and the line image data is displayed sequentially, while the ultrasound or electromagnetic wave transmitting/receiving system scans the spatial region to be imaged of the target object. It will be 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 synthetic aperture range, the imaging target line segment l
The round trip propagation time trajectories corresponding to each pixel for outputting the data of each pixel constituting the line image are different from each other. However, the functional forms of these round trip propagation time trajectories in one synthetic aperture range are the same, corresponding to the shapes of the round trip propagation time trajectories in the other one synthetic aperture range. In other words, each round trip propagation time locus for each received signal group within each synthetic aperture range for image reproduction of each line segment to be visualized in the direction directly below the scanning point (for example, the z-axis direction in FIG. 5) is We focused on the point that the received signal groups within each synthetic aperture range corresponding to each imaging target line segment to be reproduced can be commonly used even if the synthetic aperture ranges are at different positions. , this common round trip propagation time trajectory 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. 4. In FIG. 4, when reproducing an image of the line segment l1 to be imaged, which is the center line of the synthetic aperture range SA1, the focus table part PT shown in FIG. Using the address information of the round trip propagation time locus PL, it is possible to sequentially reproduce the imaging target points on the imaging target line segment l1. For example, focus table section
PT stores a group of address information regarding a hyperbolic round trip propagation time trajectory PL with each imaging target point of the imaging target line segment l as its apex. Let l1 be the line segment to be imaged for the synthetic aperture range SA1, and let l1 _k be one point to be imaged on this line segment l1 to be imaged. If the imaging target point on the imaging target line segment l corresponding to this l1 _k is l _k , and the round trip propagation time locus for this point l _K is PL _k , then the address information regarding the round trip propagation time locus PL _k is in focus. The address information of the received signal group within the synthetic aperture range SA1, that is, the received signal on the round-trip propagation time locus PL _k , is taken out from the table part PT and added from the waveform memory part, which will be described later. Uncorrected data for one pixel corresponding to point l1 _k is generated. In this case, the line segment l1 to be imaged
If this is performed for all the imaging target points, one line of uncorrected data for a line image for imaging the imaging target line segment l1 can be obtained. Next, when imaging the line segment l2 to be imaged for the synthetic aperture range SA2 which is shifted by one scanning amount P' from the synthetic aperture range SA1, the synthetic aperture range SA1 and the synthetic aperture range
The received signal group in the common range CA common to SA2 is also used in common when calculating data for the line image of the line segment l2 to be imaged. Therefore, this common range
The received signal group for CA is left even after calculating the data for the uncorrected line image of the line segment l1 to be imaged. Adding the received signal sequence obtained by scanning at scanning point SCP2 to this received signal group, the synthetic aperture range is calculated.
In the same way as SA1, the received signal group for the synthetic aperture range SA2 is processed to create the line segment l2 to be imaged.
It is possible to obtain line image data before correction. Here, if the imaging target point l2 _k on the imaging target line segment l2 corresponds to the imaging target point l _k on the imaging target line segment l, the round trip propagation time is the same as that of the imaging target point l1 _k . Address information regarding trajectory PL _k can be used in common. In this way, the address information regarding the round trip propagation time locus PL stored in the focus table unit 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-described 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 scanning point SCP at the left end of the synthetic aperture range SA1 shown in FIG.
Note that the only difference is the received signal strings of the scan point SCP2 at the right end of the synthetic aperture range SA2 and the synthetic aperture range SA2, and that the received signal strings of the common range CA are exactly the same. That is, it has a two-dimensional storage memory (hereinafter referred to as a waveform memory section) that stores only a group of received signals for one synthetic aperture range, and sequentially scans the ultrasonic transceiver to transmit and receive ultrasonic waves. , analog/digital conversion of the received signal (hereinafter referred to as A/D conversion)
After that, they are sequentially stored in the waveform memory section. At this time, for example, if the waveform memory section is filled with received signals at all scanning points within one synthetic aperture range after the start of scanning, the received signal corresponding to the oldest scanning point will be stored as the received signal at the next scanning point. The received signals at each scanning point are stored in a circular manner in the waveform memory section in the sense that the above storage method is repeated. On the other hand, in the focus table section, each time the received signal of one scanning point is stored in the waveform memory section, all address data is stored for one scanning point in the waveform memory section. The round trip propagation time locus in the focus table unit is synchronized with each scan in the waveform memory unit so that the center line of the synthetic aperture range can be reproduced by circularly shifting the line in the same direction as the sequence and always ending with the latest scan point. It follows the received signal group at the point. In this way, when the received signal at a certain scanning point is stored in the waveform memory section, the data for the line image of the center line of the synthetic aperture range with this scanning point as the terminal point is reproduced, output and displayed, and the data for the line image of the center line of the synthetic aperture range with this scanning point as the terminal point is reproduced and output and displayed. It can be seen that it is sufficient to sequentially repeat the processing operation of moving to . In addition, 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, before outputting and displaying the line image, it is possible to It is possible to output and display a reproduced image from which the effects of expansion and the like have been removed. 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. However, the number of lines corresponding to the scanning direction of the focus table section and the waveform memory section must match. FIG. 1 is a block diagram showing 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 can transmit an ultrasonic beam having a spread angle θ〓 and receive the echoes; 6 is a material to be inspected; The purpose is to image the inside of the material 6 to be inspected and to visualize internal defects. 7 is a pulse generator for applying a spike-like pulse voltage to the ultrasonic transmitter/receiver 1 to transmit an ultrasonic signal into the test material 6; 8 is a signal obtained by the ultrasonic transmitter/receiver 1; A reception amplifier 9 is an A/D converter for amplifying the ultrasonic reception signal, and the reception signal amplified to a predetermined level by the reception amplifier 8 is A/D converted to obtain a digital value and converted into a continuous signal. is discretized at a certain sampling time. 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 transceiver 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 generates a control signal for causing the ultrasonic transceiver 1 to scan the surface of the specimen 6; A measurement system control section 12 controls the timing of capturing position information when transmitting and receiving ultrasonic waves through the scan drive encoder of the ultrasonic transceiver 1, etc.; This is a scanning drive unit for scanning 1. Reference numeral 13 denotes a waveform memory section for sequentially annularly storing the received signal sequence at each scanning point converted into discrete digital values by the A/D converter 9; This is a focus table unit for reproducing images of each point on the line to be imaged from a group of received signals, and the focus table unit 1
4 receives a received signal corresponding to each scanning point from the waveform memory unit 13 in accordance with each round trip propagation time locus necessary for image reproduction of each imaging target point on the imaging target line segment l, as described later. It is also an address table in which a group of address information for reading out corresponding values in a column is written. Reference numeral 15 denotes a correction value table section for correcting the reproduced image corresponding to each point on the imaging target line, and as described later, this correction value is calculated based on the z coordinate of each point on the imaging target line in FIG. A correction value determined only by the value is calculated and stored in advance. Reference numeral 16 denotes an image reproduction control section, which controls the waveform memory section according to the T address and address information of the focus table section 14 for writing the discrete digital values obtained by the A/D converter 9 into the waveform memory section 13. (i, J) address for reading values from 13, reads values in the waveform memory section 13 sequentially or in parallel along the round trip propagation time locus, and adds or accumulates the read values. In order to perform image correction on the K address, which is the information on which imaging target point corresponds to the imaging target point on the imaging target line l, and the addition result, which is the reproduced image value, image correction is performed in synchronization with the above K address. A signal for reading a correction value from the value table section 15 is generated under control. 17 is an accumulator for adding or accumulating values read out from the waveform memory section 13 in accordance with the (i, J) address signal from the image reproduction control section 16; 18 is a multiplier; K, which is the imaging target point information 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 address signal is multiplied by the accumulation result which is the output of the accumulator 17. Reference numeral 19 denotes an image memory unit in 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; 20, an image memory unit; It is a display section, and displays a planar image in a manner in which the image area is continuously updated by displaying the reproduced image values of the image memory section 19 while sequentially line-shifting (scrolling) them. FIGS. 2 and 3 are diagrams for explaining the configurations of the waveform memory section 13, focus table section 14, and correction value table section 15 shown in FIG. 1 when the specimen 6 has a circular pipe shape. It is something. Here, regarding the waveform memory section 13 and focus table section 14 shown in FIG.
The configuration in the case where the pipe has a circular pipe shape will be explained with reference to FIG. In the same figure, the outer radius of the pipe from the pipe center O to the pipe outer wall T0 is R _p , and the pipe center O
The inner radius of the pipe from T1 to the pipe inner wall T1 is R _i , and the first
It is assumed that the ultrasonic transmitter/receiver 1 shown in the figure is scanning the surface of the pipe outer wall T0 in the circumferential direction. The aperture of the ultrasonic transmitter/receiver 1 being scanned is d, the sound speed in the piping material is c, and the center frequency of the ultrasonic wave being transmitted is the piping where the ultrasonic beam can be expected to reach one point on the inner wall T1 surface of the piping. If the synthetic aperture length on the outer wall T0 surface is L, the angle at the pipe center O into which this synthetic aperture length L is viewed is α, and the spread angle of the ultrasonic beam of the ultrasonic transmitter/receiver 1 is θ, then the ultrasonic wavelength λ is , λ=c/...(5), and the spread angle θ of the ultrasonic beam is θ=λ/d...(6). The synthetic aperture length L is calculated using the angle α, L=R _p・α (7), and at this time, α is

It is given by [ ]. Next, consider a scanning point Q (for example, Q _i ) on the surface of the pipe outer wall T0 that corresponds to the pipe center angle θ (for example, θ _i ) from the line segment l to be imaged. The position of the depth Z _p (when variable K is specified as one value, Z _pk is one value of Z _p up to the image object point l _k ) on the imaging target line l in Fig. 2 is The distance seen from this scanning point Q (for example, Q _i ) is Z (if the variable K is specified as one value, Z _k is the scanning point Q _i , and the imaging point is l _k , then one of Z value), then Z=√ ² ₀ + ( ₀ − ₀ ) ² −2 ₀ ( ₀ −
₀ )...(9) is the angle θ ^max that the farthest scanning point that the ultrasonic beam can expect from the point at depth Z ₀ forms at the pipe center O with the line segment l to be imaged as the reference line. _Z0 is given by the following equation, which is limited by the spread angle θ of the ultrasound beam.

[C] Therefore, the possible range of the angle θ _Z0 with respect to the line segment l to be imaged at the piping center O at the scanning point where the ultrasonic beam can be expected to reach the depth Z _p is |θ _Z0 | θ ^max _Z0 is given by (11). Piping inner wall TI with line segment l to be imaged
The distance between the scanning point on the surface where the ultrasonic beam can predict a point on the surface, that is, the scanning point at both ends of the pipe outer wall T0 surface with the synthetic aperture length L shown by L in FIG. 2, and that point on the pipe inner wall TI surface. If the received signal sequence does not include the ultrasonic signal that propagates Z ^max _Z0 = R _p -R _i , all the points on the line segment l to be imaged in FIG. 2 will not be reproduced as images. Z ^max _Z0 = R _p − R _i is given by the following equation.

[ ] Therefore, the capacity (M
line x N frame memory configuration), the number of lines M
is the scanning pitch of the ultrasonic transmitter/receiver 1 corresponding to the angular pitch at the pipe center O. Using Δθ, M=[L/R _p・Δθ]+1...(13) It is given in Gaussian symbol, and the number of columns is N is A/ of the received ultrasonic signal.
When the sampling time at the time of D conversion is Δt _R , N=[2·Z ^max / _Z0 = R _p −R _i /c·Δt _R +0.5] + 1 (14) is given in Gaussian symbols. However, [ ] Gauss symbol is
[ ] Indicates an operator that converts the value in parentheses into an integer. Here, when reproducing the image of the K-th imaging target point l _k at depth Z _pk on the imaging target line segment l, the received ultrasound signal of the waveform memory unit 13 in FIG. The peak values of the (i, J) address from the group are read out and added up to obtain the K-th uncorrected reproduced image value. J corresponding to the i-th row of received signal sequences in the waveform memory section 13 in FIG.
It is sufficient here to describe how to obtain the address. Kth imaging target point on imaging target line segment l
The depth Z _pk of l _k is given by Z _pk = 1/2(K-1)c・Δt _R ...(15) Imaging the scanning point Q _i corresponding to the i-th received signal sequence The angle θ _i in FIG. 2, which is the angle of the target line segment l, is calculated using the number of lines _M determined by equation (13) of the waveform memory unit 13 in FIG.・Δθ ……(16) becomes. The distance between this scanning point Q _i and the imaging target point l _k
Z _k is given by the following equation using Z _pk and θ _i of equations (15) and (16). Z _k = √ ² ₀ + ( _p − _pk ) ² −2 _p ( _p −
_pk ) _i ...(17) The J address (column) 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〕+1 ...(18) Given as a Gaussian signal. However, here, for the imaging target point l _k , the range of scanning points Q _i that can be defined in the waveform memory unit 13, that is, the range of i addresses (rows), is equation (10), equation (11), and (15 ) and (16), it is determined by the following equation.
It is specified that it can take the value i ^min _k to 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 object to be imaged, and reflected waves from the object to be imaged are received. Then, the received signal group for one synthetic aperture range is stored in the waveform memory section, and the data is accumulated or added for each data group using each data group in the waveform memory section corresponding to each round trip propagation time locus and synthesized. The data for the line image of the center line of the aperture range is sequentially displayed as an image,
Imaging the target object Since the target spatial region is visualized while scanning the ultrasonic or electromagnetic wave transmitting/receiving system, it is possible to save the required memory capacity and use the limited memory area effectively. In addition, there are excellent effects in that image reproduction processing time can be increased (in real time), and high-quality image reproduction can be realized regardless of distance.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing an apparatus to which an embodiment of the object imaging method using ultrasound or electromagnetic waves of the present invention is applied, and FIG. 2 illustrates the waveform memory section and focus table section shown in FIG. 1. 3 is a diagram for explaining the correction value table section shown in FIG. 1. FIG. 4 is a diagram for explaining the object imaging method using ultrasound or electromagnetic waves according to the present invention. Fig. 5 is a diagram for explaining the object imaging method based on the conventional synthetic aperture method, and Fig. 6 shows the received signal of the ultrasonic wave reflected by the object to be imaged by the ultrasonic transmitter/receiver shown in Fig. 5. A diagram for explaining the round-trip propagation time trajectory from transmission to reception of a received signal when it is received along a scanning line (plane). Figure 7 is an object imaging method based on the synthetic aperture method shown in Figure 5. To explain the imaging area (line to be imaged), the ultrasound reception signal group necessary for image reproduction, and the necessary scanning range of the ultrasound transmitter/receiver necessary to obtain the reception signal group. This is a diagram. In the figure, 1 is an ultrasonic transmitter/receiver, 2 is an ultrasonic beam, 5 is a scanning line (plane), 6 is a material to be inspected, 7 is a pulse generator, 8 is a receiving amplifier, 9 is an A/D converter, 10 1 is a transmission/reception timing controller, 11 is a measurement system control unit, 12 is a scanning drive unit, 13 is a waveform memory unit, 14 is a focus table unit, 15 is a correction value table unit, 16 is an image reproduction control unit, and 17 is an accumulation unit. 18 is a multiplier, 19 is an image memory section, and 20 is an image display section. In addition, the same symbols in the figures are the same,
or a corresponding portion.

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. The target object is irradiated with a turbulent ultrasonic wave or electromagnetic wave beam, receives the reflected wave from the target object, and uses a round-trip propagation time trajectory along the scanning direction determined by the round-trip propagation time from transmission to reception of the received signal. In an object imaging method using ultrasonic waves or electromagnetic waves based on a synthetic aperture method to obtain an image of When storing sequentially in the waveform memory section consisting of a two-dimensional frame memory configuration corresponding to scanning points only within one synthetic aperture range, at the same time, the received signals of each scanning point are stored in a circular manner using a ring count address.
1 All the address data in the focus table section in which the corresponding address data in the waveform memory section corresponding to the plurality of reciprocating propagation time trajectories necessary to reproduce the image of the center line of the synthetic aperture range are tabulated.
The line is shifted circularly by a ring count by each scanning point, and the latest scanning point is always the terminal point1.
The received signal data array in the waveform memory section and the address data array in the focus table section are read out using each address information group in the focus table section in which the received signal data arrangement in the waveform memory section and the address data arrangement in the focus table section are made to correspond so as to reproduce an image of the center line of the synthetic aperture range. Accumulating data for each data group using each data group in the waveform memory section, and sequentially displaying data for a line image of a center line of a synthetic aperture range with the latest scanning point as a terminal point. A method for imaging an object using ultrasonic waves or electromagnetic waves, characterized in that the spatial region to be imaged of the target object is visualized while scanning with the ultrasonic wave or electromagnetic wave transmitting/receiving system. 2 correcting the line image data by multiplying it by an image correction value determined by the distance directly below the scanning line or scanning surface of the ultrasound or electromagnetic wave transmission/reception system;
2. The object imaging method using ultrasonic waves or electromagnetic waves according to claim 1, wherein data for line images whose center lines of the synthetic aperture range have been corrected are displayed sequentially. 3. Calculate in advance the image correction value determined by the direct distance corresponding to each imaging target point on the center line of the synthetic aperture range from the scanning line or scanning plane, create a table, and store it in a one-dimensional line memory. Object imaging using ultrasound or electromagnetic waves according to claim 2, wherein the image correction values are read out from the line memory corresponding to each imaging target point and multiplied by each image correction value. Method.