JPH0572980B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention detects defects in metal materials, for example,
An object imaging device in an ultrasonic non-destructive inspection device that can display the defect image in high resolution and in real time, or a synthetic aperture that can visualize the condition of the ground surface from a distance in the sky using electromagnetic waves. This invention relates to an object imaging device using 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 in this method, 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 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, especially in recent years, nuclear power
It is not always possible to fully meet the demands for quantifying the shape of defects in materials in order to evaluate the soundness and remaining life of structural materials such as welded joints of piping in plants such as thermal power plants using fracture mechanics methods. This is the current situation. 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. 10 and 11. In Fig. 10, 1 is an ultrasonic transmitter/receiver that has an aperture d and can transmit and receive ultrasound, 2 is an ultrasonic beam transmitted from the ultrasonic transmitter/receiver 1 and has a beam divergence angle θω, and 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 ultrasonic wave from the ultrasonic transmitter/receiver 1 is f, and the sound speed in the propagation medium 4 is c.
In addition, the ultrasonic beam 2 is directed to the object 3 to be imaged.
Let L be the length of the scanning range of the ultrasonic transmitter/receiver 1 that can be expected. The scanning direction of the ultrasonic transceiver 1 is defined as the x-axis, and the depth direction perpendicular to the x-axis is defined as z.
When viewed from the axis, the object to be visualized 3 is located at (Xo, Zo) in the ). FIG. 11 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. 10 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√ (x- Xo) ² + Zo ² ……(1) is given. 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 received signals received within a range of length L,
The signal intensity due to object reflection, which is spatiotemporally dispersed on the hyperbola in the figure, can be compressed onto the corresponding object point, which is the object 3 to be visualized. This means that each scanning point on the scanning line 5 in FIG. 10 sequentially occupies an aperture of an ultrasonic transceiver having an aperture of length L determined by the spread angle θω of the ultrasonic beam 2. In other words, this is physically equivalent to irradiating the imaging target object 3 with an ultrasonic transmitter/receiver having an aperture L. This length L is called a synthetic aperture length, and the method of forming an image of the imaging object 3 in this way is called a synthetic aperture method. At this time, the azimuth resolution δx is given by the ultrasound wavelength λ: δx = λ/LZo (2), where L is given by the spread of the ultrasound beam λ/d and the distance ZO to the imaging object 3. L=λ/dZo...(3), so substituting L determined by equation (3) into equation (2),
In the end, the azimuth resolution becomes δx=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 xz plane in FIG. 0 is to be implemented will be described using FIG. 12. 1st
In Fig. 2, the area reconstructed 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, and this image Point to be imaged on line segment to be imaged l _K
The received signal group necessary for reproducing is the value of the received signal on the hyperbola indicated by the two-dot chain line in the figure. The synthetic aperture length L at this time is defined corresponding to the position with the greatest distance in the z direction to be imaged on the xz plane. Further, the range in which the hyperbola of the phase history is defined is determined by the spread of the ultrasound beam of the ultrasound transmitter/receiver, and is indicated by a dotted line in the figure. That is, in order to image an area with the length of the synthetic aperture length L in the scanning direction, it is necessary to
This means that the received signal groups of all scanning points in the 2L scanning range are required. In the figure, the received signal group necessary to image the imaging area AR1 with a width L in the x-axis direction is the entire received signal group in the scanning range SC1 with a length of 2L.
Similarly, the received signal group required to image the imaging area AR2 having the width L becomes the entire received signal group of the scanning range SC2 having a length of 2L. When attempting to image a wide range of imaging target areas using this method, the phase history line indicated by a hyperbola for image reproduction is an image having different values in the z-axis direction (direction orthogonal to the scanning direction). Since the shapes of these functions differ for the points to be converted, the received signal string at each scanning point is A/D converted and stored in memory, and the received signal string for each scanning point is all unidirectional. corresponds to a scanning point, and one direction corresponds to time, that is, distance in the Z-axis direction. It is necessary to sequentially pick out and add up the signal values in the received signal sequence. 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 device 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. There were problems such as an extremely long image reproduction processing time. 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 device using ultrasonic waves or electromagnetic waves using the synthetic aperture method. The purpose of this invention is to obtain an object imaging device using ultrasonic waves or electromagnetic waves that can perform real-time imaging. [Means for Solving the Problems] The object imaging device using ultrasonic waves or electromagnetic waves according to the present invention uniquely solves the problem from the phase delay of the received signal from the time when the ultrasonic wave or electromagnetic wave beam is transmitted to the target object to when it is received. In an object imaging device based on the synthetic aperture method that obtains a target object image using a phase history line along a determined scanning direction, the received signal is discretized at a certain sampling time using A/D conversion means. Discrete digital values are stored in the A/D memory means for one line at one scanning point,
The digital value group stored in the waveform memory means, which sequentially stores the digital value string stored in the D memory means, is sequentially line-shifted by the equivalent of one scanning line by the latch gate means, and the phase history line calculated in advance is simultaneously reading and adding digital values in the waveform memory means corresponding to one phase history line by an adding means according to address information obtained from a phase history line table means storing corresponding address information in the waveform memory means; The data of one pixel obtained from this addition means is stored sequentially, the line image data corresponding to the center line within the synthetic aperture range is stored in the image memory means, and the line image data in the image memory is digitally/ The image is displayed while being scrolled sequentially while being converted to analog. [Operation] The image object generation device using ultrasonic waves or electromagnetic waves according to the present invention irradiates a target object with ultrasonic waves or electromagnetic waves as a beam, receives an echo signal from the target object, and converts it into analog/digital data using an A/D conversion means.
Digital conversion (hereinafter referred to as A/D conversion),
The A/D converted digital signal is sequentially stored in the waveform memory means for one line at each scanning point, and when the data for each scanning point is stored, the data already stored in the waveform memory means is removed by the latch gate means. The entire data is shifted by an amount equivalent to one line, and the digital values in the waveform memory means for one phase history line are simultaneously read and added by the adding means according to the address information obtained from the phase history line table means, and one pixel data is obtained. This process is repeated sequentially to obtain line image data corresponding to the center line within the synthetic aperture range, and the line image data obtained for each synthetic aperture range is sequentially scrolled and displayed to image the target object. become [Example] Hereinafter, an example of the present invention will be described with reference to the drawings. First, in order to make the invention easier to understand, the basic principles of the embodiments of the invention will be explained. 1
In order to image the line segment l to be imaged of the center line within the synthetic aperture range, the phase history lines corresponding to each pixel for outputting the data of each image constituting the line image of the line segment l to be imaged 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. That is, each phase history line for each received signal group within each synthetic aperture range for image reproduction of each imaging target line segment in the direction directly below the scanning point (for example, the z direction in FIG. 10) is The common phase is The history line is what is used for image data processing. The synthetic aperture range here is defined as the one corresponding to the position farthest from the scanning point where the image is to be reproduced. This will be explained using FIG. 9. In FIG. 9, 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 of the phase history line table PT shown in the figure is required for the received signal group of the synthetic aperture range SA1. Using the address information of the 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 line table section PT stores address information regarding a hyperbolic phase history line PL with each store of the line segment l to be imaged as its apex.
A line segment l1 to be imaged for the synthetic aperture range SA1 is assumed, and one point to be imaged on this line segment l1 to be imaged _{is l1K} . If the imaging target point on the imaging target line segment l corresponding to this l1 _K is l _K , and the phase history line for this point l _K is PL _K , the address information regarding the phase history line PL _K is stored in the phase history line table. Department 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 one pixel data corresponding to the imaging target point _l1K . If such a process is performed for all the imaging target points of the imaging target line segment l1, one line worth of 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 that is shifted by one scan P _S from the synthetic aperture range SA1, the common range CA that is common to the synthetic aperture range SA1 and the synthetic aperture range SA2 is received. The signal group is also commonly used when calculating data for the line image of the line segment l2 to be imaged. Therefore, the received signal group for this range CA is left even after calculating the line image data of the line segment l1 to be imaged. The received signal sequence obtained by scanning at the scanning point SCP2 is added to such a received signal group, and the received signal group for the synthetic aperture range SA2 is processed in the same way as for the synthetic aperture range SA1 to obtain the line segment to be imaged. Line image data for l2 can be obtained. Here, if the imaging target point l2 _K on the imaging target line segment l2 corresponds to the l _K point on the imaging target line segment l, the address information regarding the same phase history line PL _K as point l1 _K is shared. It can be used for. In this way, the address information regarding the phase history line PL stored in the phase history line table section PL 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 processing operations described above, 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 leftmost scanning point SCP1 of the synthetic aperture range SA1 and the rightmost scanning point of the synthetic aperture range SA2 shown in FIG.
Note that the received signal sequences of the common range CA are exactly the same, only the received signal sequence of SCP2 is different. 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. , the received signal is A/
When storing in the waveform memory unit after D conversion, all received signal groups in the waveform memory unit are line shifted by one scan, and the received signal sequence corresponding to the scan point immediately before the scan point to be stored is line shifted. This received signal sequence is stored in the previously stored column after line shifting. Next, it is understood that the processing operations of reproducing the line image data using the phase history line table section PT, outputting and displaying it, and moving to the next scanning point can be repeated in sequence. In addition,
When processing the received signal group, it has been described that the received signal group corresponding to one synthetic aperture range is stored in the waveform memory section, but the waveform memory section may have a larger capacity. FIG. 1 is a block diagram of an object imaging apparatus using ultrasonic waves or electromagnetic waves according to an embodiment of the present invention. In the figure, 1 is an ultrasonic transmitter/receiver that has an aperture d and transmits an ultrasonic beam with a divergence angle θω and receives an echo, and 6 is a material to be inspected. The purpose is to image the inside of the 6 and visualize internal defects. 11 is a pulse generator for applying a spike-like pulse voltage to the ultrasonic transmitter/receiver 1 and causes the ultrasonic transmitter/receiver 1 to transmit an ultrasonic signal into the test material 6; A reception amplification section 13 converts the reception signal amplified to a predetermined level by the reception amplification section 12 to obtain a digital value, and converts the continuous signal (analog signal) to a certain predetermined value. This is an A/D converter for discretization using the specified sampling time. 14 generates a timing signal for applying a pulse voltage from the pulse generator 11 to the ultrasonic transceiver 1, and
The A/D conversion unit 13 is a transmission/reception timing control unit that controls the start timing of A/D conversion of the received signal. Reference numeral 15 denotes a measurement system control unit for comprehensively controlling the measurement system, for example, from a microcomputer, which provides the transmission/reception timing control unit 14 with a control signal for generating the timing signal, and also controls the ultrasonic transceiver 1. A control signal is generated to scan the surface of the specimen 6, and furthermore, an encoder, etc. (not shown) of a scan drive unit 16 (described later) of the ultrasonic transceiver 1 generates a control signal to scan the surface of the specimen 6, and transmits positional information when the ultrasonic transceiver 1 transmits and receives ultrasonic waves. (2) control the timing of capture. Reference numeral 16 indicates a scanning drive unit for scanning the ultrasonic transmitter/receiver 1 using the scanning control signal from the measurement system control unit 15, and 17 indicates a discrete digital value obtained by the A/D conversion unit 13 at each scanning point. No. 1
This is an image reproduction processing section consisting of a waveform memory, etc., which sequentially stores each measurement and sequentially performs image reproduction processing while referring to a phase history line table section 18, which will be described later. 1
Reference numeral 8 denotes a phase history line table section used for reproducing images of each point on the imaging target line from the received signal group within the synthetic aperture range, and as described later, the image reproduction processing section 17 Following each phase history line necessary to image reconstruct each line,
It is also an address table in which address information for reading out the corresponding value in the received signal string corresponding to each scanning line is written, and the above-mentioned image reproduction processing section 17
has provided the above address information. Reference numeral 19 denotes an image display section, in which 1 obtained by the image reproduction processing section 17 is displayed.
The reproduced image values for the lines are digital-to-analog converted and displayed while sequentially shifting the lines, thereby displaying a planar image in a manner that continuously updates the image area. FIG. 2 is a detailed block diagram of the image reproduction processing section 17. In the same figure, 21 is the above A/
This is an A/D memory unit that sequentially stores the discrete digital value string obtained by the D conversion unit 13.
3 (not shown) at one scanning point.
A line data string (that is, a digital value discretized at a certain sampling period) is temporarily stored. 22 is a waveform memory unit that sequentially stores one line data string transferred from the A/D memory unit 21, and each row in the figure represents one line memory, and this is the number of rows. The address and chip select signal for each line memory are independently supplied from an address switching section 26 (to be described later), and the read/write
A write signal (hereinafter referred to as R/W signal) is commonly transmitted to each line memory by the image reproduction control unit 2, which will be described later.
It is supplied by 7. That is, in the waveform memory section 22, all the row line memories are accessed at the same time using independent addresses. Reference numeral 23 denotes a latch gate section that operates when simultaneously line shifting the waveform memory section 22 and storing the data string of the A/D memory section 21 in the line memory of the top row in the figure of the waveform memory section 22. The data in the i-th row of the waveform memory unit 22 is latched and connected to the i+1-th memory of the waveform memory unit 22 via the gate. That is, the latch gate unit 23 is configured to latch the data of one j column of each row of the waveform memory 22, shift it downward by one row, and store it in each row within the same j column of the waveform memory 22, and, It is configured to latch the j-column data received from the A/D memory section 21 and store it in the j-column of the top row of the waveform memory section 22. Reference numeral 24 denotes an adding unit that simultaneously adds the data group obtained by the waveform memory 22 in parallel, and 25 stores the added one-pixel data in sequence at the address indicated by the K address, thereby storing one line of image data. This is an image memory section formed by 2
Reference numeral 6 denotes an address switching unit which converts a line memory chip select signal and address information J supplied independently from the phase history line table unit 18, and a line memory chip select signal supplied from an image reproduction control unit 27 (described later). The memory address signal S S via the memory shift address bus including the memory address signal S _S is selected by the switching signal S _A , and the address and chip select signal are independently supplied to each line memory of the waveform memory section 22. Reference numeral 27 denotes an image reproduction control section that comprehensively controls the above-mentioned image processing system, and uses address information calculated and stored in advance in the phase history line table section 18, that is, a line memory in the waveform memory section 22. A T address for simultaneously reading and controlling a memory group having the same structure as the waveform memory section 22 that stores the chip select signal and column address data J of the rows of , line shift of the waveform memory section 22, and data strings to the waveform memory section 22. the memory shift address specified when inputting the line, the address switching signal S _A of the address switching unit 26, the R/W signal that controls reading and writing of the waveform memory 22, and the latch/gate unit 23 that operates during the line shift. A latch signal S _R and a gate signal S _G ,
When writing one pixel data to the image memory section 25,
The K address and R/W signal specifying the position are controlled respectively. T address to the phase history line table section 18 and address K to the image memory section 25
are similar, and fixed addressing is performed sequentially from 1 to the address of the image memory unit 25 each time. The configuration of the waveform memory unit 22 and phase history line table 18 shown in FIG. 2 will be described below with reference to FIG. 3 when the test material 6 is in the shape of a circular pipe. In the same figure, the pipe radius from the pipe center O to the pipe outer wall TO is R _O , the pipe inner radius from the pipe center O to the pipe inner diameter TI is Ri, and the ultrasonic transmission/reception signal 1 shown in Fig. 1 is the pipe outer wall TO Assume that the surface is being scanned in the circumferential direction. The aperture of the ultrasonic transmitter/receiver 1 being scanned is d, the sound velocity in the piping material is C, the center frequency of the ultrasonic wave being transmitted is f, and the ultrasonic beam can be expected to hit one point on the TI surface of the inner wall of the piping. If the synthetic opening length on the pipe outer wall TO is L, the angle at the pipe center O into which this synthetic opening length L is viewed is α, and the spread angle of the ultrasonic beam of the ultrasonic transmission/reception signal 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 P (for example, Pi) 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. Depth Zo of the line segment l to be imaged in the figure (if variable K is specified as one value, Z _OK is the position of one value of Zo up to the image target point l _K )
The expected distance from this scanning point P (for example, Pi) is Z
(If the variable K is specified as one value, Z _K is the scanning point
√ ² + ₍ -) ² -2 (-
)
cos θ ...(9), and the angle θ ^max _ZO that the farthest scanning point that can be expected from the ultrasonic beam from a point with a distance Z _O makes with the line segment l to be imaged as the reference line at the pipe center O is It is limited by the ultrasound beam divergence angle θ and is given by the following equation.

[ ] Therefore, the line segment l to be imaged at the piping center O of the scanning point where the ultrasonic beam can be expected to reach a point with depth Z _O
The possible range of the angle θ _ZO with reference line θ ZO is given by |θ _ZO | θ ^max _Zp ...(11). Piping inner wall TI with line segment l to be imaged
A scanning point on the surface where the ultrasonic beam can be detected, that is, the outer wall of the pipe with a synthetic aperture length L indicated by L in the figure.
The imaging target line in the figure must be defined as the received signal train up to the ultrasonic signal propagating the distance Z ^max _Zp=Rp-Ri between the scanning points at both ends on the TO surface and that point on the TI surface of the pipe inner wall. Therefore, all of the portion 1 will not be reproduced as an image.
Z ^max _Zp=Rp-Ri is given by the following equation.

[ ] Therefore, the capacity (M
×N frame memory configuration), the number of rows M corresponds to the angular pitch at the piping center O of one scan pitch of the ultrasonic transmitting/receiving signal. Using Δθ, M = [L/Ro・Δθ] Gaussian signal + 1... (13), and the number of columns N is the A/D of the ultrasonic received signal.
Assuming the sampling time during conversion as Δt _R , N=[2・Z ^max / _Zp=Rp-Ri /C・Δt _R +0.5
] Gaussian signal +1 ...(14) is given. Here, when reproducing the image of the K-th point l _K at depth Z _OK on the line segment l to be imaged, from the ultrasonic reception signal group (i, J) Read and add the peak values of the addresses, and also add them to the image memory section 1 in Figure 2.
It will be written to the K address of 8. It is sufficient here to describe how to obtain the column address J corresponding to the received signal column in the i-th row (row address i) of the waveform memory section 22. The depth Z _OK of the K-th image target point l _K on the imaging target line segment l is given by Z _OK = 1/2 (K-1) C・Δt _R ...(15), and the i-th line The angle between the scanning point Pi corresponding to the received signal sequence and the line segment l to be imaged, that is, the third
The angle θi in the figure is determined by equation (13) in the waveform memory section 2.
Using the number M of rows in 2, θi=(M+1/2+i)Δθ (16). The distance between this scanning point Pi and the imaging target point l _K
Z _K is given by the following equation similarly to equation (9) using Z _OK and θi of equations (15) and (16). √ ² + (+ _OK ) ² +2 (-
_OK )...(17) The column address J of the value to be read from the i-th received signal column of the waveform memory unit 22 for the above distance Z _K is J = [2・Z _K /C・Δt _R +0.5] Gauss The signal +1 is given by (18). However, here, for the imaging target point l _K , the range of scanning points Pi that can be defined in the waveform memory unit 22, that is, the range of row addresses i, is (10)
i ^min _K ~i determined by the following equation from equations, (11), (15), and (16)
^max _K
It is specified that it can take the value of .

〔Effect of the invention〕

As described above, according to the present invention, an object imaging method using ultrasonic waves or electromagnetic waves based on the synthetic aperture method with excellent azimuth resolution is used to A/D convert the received signal obtained at the scanning point by the transmitter/receiver. The digital value is stored in the waveform memory section, and during this storage, all the data for one synthetic aperture range already stored in the waveform memory section is shifted by one row pitch,
In the waveform memory section corresponding to one phase history line of the phase history line table section according to the address information obtained from the phase history line table section storing the corresponding address information in the waveform memory section according to the phase history line calculated in advance. The digital values of are simultaneously read out and added to obtain one pixel data, and the pixel data obtained in this way is stored sequentially to obtain line image data corresponding to the center line within the synthetic aperture range, This line image data is sequentially scrolled and displayed while being D/A converted, and the above operation is performed at each scanning point.
Since it is configured to repeat, it is possible to save the necessary memory and make effective use of the limited memory area, and at the same time, it has the effect of achieving faster image playback processing time (real-time processing). .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an overview of an embodiment of the object imaging device of the present invention, FIG. 2 is a detailed block configuration diagram of the image reproduction processing section shown in FIG. 1, and FIG. 4 is a flowchart of calculation processing for specifically determining the phase history line table section, and FIGS. 5 and 6 are diagrams for explaining the waveform memory section and phase history line table section shown in An explanatory diagram showing the array format in which the address information obtained in the above-mentioned FIG. 4 of the phase history line table section is stored, FIG. FIG. 9 is a block diagram showing another embodiment of the object imaging device according to the present invention, and FIG. 9 is a diagram for explaining the principle of the object imaging method of the object imaging device according to the present invention.
Fig. 10 is a diagram for explaining an object image reproduction method based on the conventional synthetic aperture method, and Fig. 11 is an ultrasonic reception signal obtained by the ultrasonic transceiver in Fig. 10 reflected by the object to be visualized. Figure 12 shows the phase history from transmission to reception of the received signal when it is received along the scanning line (plane). Figure 12 shows the imaging area (imaging target line) in the object imaging method based on the synthetic aperture method. FIG. 3 is a diagram for explaining a group of ultrasonic reception signals necessary for image reproduction, and a necessary scanning range of an ultrasonic transmitter/receiver necessary to obtain the group of reception signals. In the figure, 1 is an ultrasonic transceiver, 11 is a pulse generator, 12 is a reception amplification unit, 13 is an A/D conversion unit, 14 is a transmission/reception timing control unit, 15 is a measurement system control unit, 16 is a scan drive unit, 17 is an image reproduction processing section, 18 is a phase history table section, 19 is an image display section, 21 is an A/D memory section, 22 is a waveform memory section, 23 is a latch/gate section, 24 is an addition section, 2
5 is an image memory section, 27 is an image reproduction control section, 31
is an antenna, 32 is a position detection section, 33 is a measurement system control section, 34 is a pulse generation section, 35 is a reception amplification section,
36 is a transmission/reception timing control section. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. When visualizing an image of a target object using ultrasound or electromagnetic waves, the ultrasound or electromagnetic waves spatially spread to the target object while mechanically or electronically scanning the ultrasound or electromagnetic wave transmission/reception system. While irradiating the beam, the 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 that is uniquely determined from the phase delay of the received signal from transmission to reception. In an object imaging device using ultrasonic waves or electromagnetic waves based on a synthetic aperture method to obtain a digital signal, an A/D conversion means for discretizing the received signal at a certain sampling time to obtain a digital value; A/D memory means for storing discrete digital values for one line at one scanning point, waveform memory means for sequentially storing the digital value string stored in the A/D memory means, and the waveform memory. latch/gate means configured to sequentially line shift a group of digital values stored in the means by an amount equivalent to one scanning line; and corresponding address information in the waveform memory means based on a pre-calculated phase history line. Simultaneously reading and adding digital values in the waveform memory means corresponding to one phase history line of the phase history line table means according to the stored phase history line table means and address information obtained from the phase history line table means. an adding means, an image memory means for sequentially storing the data of one pixel obtained by the adding means, and an image memory means for storing data of a line image corresponding to the center line within the synthetic aperture range; 1. An object imaging device using ultrasonic waves or electromagnetic waves, comprising: image display means for sequentially scrolling and displaying line image data while digital/analog converting the data.