JPS6334738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus that scans and converts an ultrasonic image, which is scanned so that extended lines of scanning lines intersect at one point, into a standard television image signal and displays the signal.

As is well known, the fan-shaped scanning ultrasonic diagnostic apparatus sequentially emits ultrasound pulses in each direction in a fan shape, and displays the signals returned from each direction in a fan shape on a display. When using the standard television system for this display, the fan-shaped image must be scan-converted to standard television scanning. conventionally,
A scan conversion method is used in which the ultrasonic wave is deflected to an angle in which the tangent of the deflection angle is proportional. FIG. 1 is a diagram illustrating the relationship between ultrasonic scanning lines according to such a conventional method, in which an ultrasonic probe 10 performs scanning indicated by ultrasonic scanning lines 1, 2, . . . 9.
The scanning lines of the television display are 1', 2', ... 7', and the tangent of the deflection angle is proportional, so the ultrasonic scanning lines 1, 2, ... 9 are the television scanning lines 1', 2'. ,…
...The length ΔY that cuts 7' is constant on one television scanning line.

In such conventional systems, the scanning pitch of the ultrasonic beam is uniquely determined by the deflection angle and the number of scanning lines, and the scanning density cannot be freely set depending on the deflection direction. Furthermore, this has limited the deflection methods of the ultrasonic probe.

The present invention has been made in view of such conventional problems, and is not limited to fan-shaped scanning, but also applies to ultrasonic beam scanning in which the extended lines of scanning lines intersect equivalently at one point. The present invention also provides an ultrasonic diagnostic device that can convert scans with arbitrarily set scan densities into standard television scans and display them using a simple method.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram for explaining a fan-shaped scanning method that is more general than that shown in FIG. 1, and the scanning line density changes depending on the angle. The ultrasonic video signal is sampled at the black circle points indicating the intersections of the ultrasonic scanning lines 1, 2, . . . 9 and the television scanning lines 1', 2', . . . 7'. Since the television scanning lines are equally spaced, this sampling interval is a fixed time determined for each ultrasonic scanning line. The angle of the ultrasonic scanning line is not uniform but irregular because the scanning line density is set arbitrarily. For example, the black circles on the television scanning line 7' are arranged at irregular intervals as shown by ΔY ₁ , ΔY ₂ , . . . ΔY ₈ .

FIG. 3 is a block diagram showing one embodiment of the present invention. The scanning line counter 11 sequentially selects the scanning lines of the fan-shaped scan and supplies the ultrasonic scanning line number N to the transmitter control section 12, ROM 15, pulse generator 19, and write address generator 20. Under the control of the transmitter control unit 12, the transmitter 13 generates 32 transmission pulses at energization timings determined by the ultrasonic scanning line number N. This transmitted pulse is
An ultrasonic probe 10 composed of an array of 32 ultrasonic transducers sends pulses of a specified directional ultrasonic beam into the subject. Furthermore, the reflected ultrasound from within the subject is received by the ultrasound probe 10 and delayed by a predetermined time by the variable delay section 14. The variable delay section 14 is detailed
It is composed of 32 variable extension lines DL ₁ , DL ₂ , _. By adding the outputs of these 32 delay lines in an adder 16, a reception directivity determined by the ultrasonic scanning line number N is obtained. This addition output signal is amplified and detected by a detector 17. A sampling pulse is generated by a pulse generator 19 at a timing corresponding to the black circle in FIG. 2 determined by the ultrasonic scanning line number N from the scanning line counter 11. Using this sampling pulse, the output of the detector 17 is converted from analog to digital by an analog to digital converter 18, and this output is stored in the main storage section 21. Furthermore, this sampling pulse controls the writing timing of the main memory section 21. Further, the write address generator 20 generates the write address in the main storage unit 21 based on the position in the ultrasonic scanning direction obtained by counting the sampling pulses and the ultrasonic scanning line number N which is a signal from the scanning line counter 11. Control. The readout control section 22 of the main storage section 21 reads data for one horizontal scanning line of the television from the main storage section 21 and transfers it to the buffer storage section 24 . This transfer is performed sequentially from the end of the ultrasonic scanning line, and during this transfer process, the latch 23 simultaneously transfers data shifted by one ultrasonic scanning line to the buffer storage unit 2.
Transfer and store to 4. The buffer storage unit 24 is composed of line memories A and B having the same configuration, one for writing and the other for reading, and the memory is switched for every horizontal scanning line of the television.

The read address generating section 25, which is a circuit that controls selective reading of display data from the buffer storage section 24, interpolates the number N of the television scanning line corresponding to the horizontal position on the television display by one-fourth. Operate and output using the included type. Let M be a signal that selects this interpolated data. Furthermore, M is 0, 1, 2,
The data to be displayed is expressed as D _N,M with a value of 3 and O indicating no interpolation. Output N of address generator 25
Data D _N,0 of TV scanning line N and TV scanning line N+1 is sent from the buffer storage unit 24 using the address .
and D _N+1,0 in parallel. These two pieces of data are added by the adder 26-1 to obtain 1/2 interpolated data D _N,2
make. Further, adder 26-2 adds D _N,0 and D _N,2 ,
Add D _N,2 and D _N+1,0 by adder 26-3,
Create quarter interpolated data D _N,1 and D _N,3 . To show the relationship between D _N,M, D _N,2 = 1/2 (D _N,0 + D _N+1,0 ) D _N,1 = 1/2 (D _N,0 + D _N,2 ) D _{N ,3} = 1/2 (D _N,2 +D _N+1,0 ).

The data selector 27 selects M from among D _N,0 , D _N,1 , D _N,2 , and D _N,3 by the signal M that selects the interpolation data output by the read address generation section 25 . Select the corresponding data. The selected data is converted into an analog signal by a DA converter 28, mixed with a standard television synchronization signal by a video mixer 29, and displayed on a television monitor 30.

FIG. 4 shows the read address generation section 25 of FIG.
This is a block diagram illustrating the pitch data generation ROM 25-1 as the first sub-storage section in more detail.
, an adder 25-2, a latch 25-3, an address converter 25-4 as a second sub-storage section, and a switch 25-5. Pitch data generation
The ROM 25-1 generates a display pitch signal P of about 18 bits determined by the television horizontal scanning line from the readout control 22. In the display shown in FIG. 2, this display pitch P has a smaller value as the television scanning line goes lower, and is inversely proportional to the distance between the intersection of the ultrasonic scanning lines and the television scanning line. On a television display, display points are arranged at equal intervals across the entire screen, and these points constitute an image. For each display point, the display pitch P is accumulated by an accumulative adder constituted by an adder 25-2 and a latch 25-3 to obtain a standardized scanning line number N'. Until now, the number of ultrasonic scanning lines was 10, but since then it has become more practical.
The explanation will be based on the assumption that there are about 100 pieces. In this case, the scanning line number N is a 7-bit signal. In addition, it is appropriate for a TV display to display approximately 512 points in the horizontal direction. Therefore, the appropriate display fineness is about 9 bits.
For the above reasons, the precision of N' is determined by the upper 9 bits of the cumulative addition result. Since this standardized scanning line number is the result of cumulative addition, the difference between two adjacent points in the horizontal direction on the TV display does not change with horizontal movement, and this data N' is used to store buffers. If the address is a readout address from the section, black circles will be displayed at equal intervals in the television scanning direction as shown in FIG. 1 of the conventional example. Even if the black circles are arranged at unequal intervals in the television scanning direction as shown in FIG. 2, the ratio of the intervals is constant with respect to the television scanning line. Therefore, the address in the buffer storage section 24 of the target data to be displayed is determined by the address converter 25-4, which is unchanged depending on the television scanning line. The output of this address converter is 7
A bit scanning line number N and a 2-bit interpolation data selection signal M can be obtained simultaneously. Further, the address converter 25-4 can be configured with a 4608-bit read-only memory that obtains a 9-bit output from a 9-bit input. The output N of the address conversion and the transfer address signal of the read control unit 22 are connected to the switch 25-
5, they are switched in accordance with the horizontal scanning period of the television display, and serve as the read and write addresses of the buffer storage section, respectively. The data read from buffer memory is D _N,0 as mentioned above.
D _N+1,0 . Further, the interpolation data selection signal M is supplied to the data selector 27 to select interpolation data.

As described above, according to the present invention, the fan-shaped ultrasonic scanning line density can be arbitrarily set depending on the deflection direction, and therefore, the optimum scanning line density matching the purpose can be selected. Moreover, since the display position is determined entirely in digital quantities, high-precision display is achieved, and optimal interpolation suitable for the display position is performed, resulting in good image quality and a simple configuration.

FIG. 5 is a block diagram illustrating another embodiment of the present invention, which is an improved version of the address converter shown in FIG. 4. The most significant bit of the 9-bit normalized scanning line number N' obtained in the same way as in the previous case changes from 0 to 1.The most significant bit of the ultrasound scanning line number N where the horizontal position of the television display is displayed. Set the display pitch P to match the 65th line where the bit changes from 0 to 1. As a result, the most significant bit of the standardized scanning line number N' matches the most significant bit of the ultrasonic scanning line N. However, the output of the address converter 25-4 shown in FIG. 4 is reduced from 9 bits to 8 bits as shown in FIG.

As described above, the capacity of the read-only memory of the address converter can be reduced to 4096 bits. Moreover, when the output of the address converter becomes 8 bits as shown in the example, commercially available ROM and
It is very useful because many parts have 4-bit or 8-bit RAM.

FIG. 6 is a diagram showing the relationship between ultrasonic scanning lines and television scanning lines, explaining another embodiment of the present invention. The ultrasonic probe 10' has transducers arranged on an arc, and emits and receives ultrasonic beams indicated by 1, 2, . . . 9 outward from the center of the arc. The transducers are evenly spaced and scanning is performed at equal angular pitch. When displaying images on a standard television that performs such scanning, the black circles that are the intersections with the television scanning lines ₁ ', ₂ ', . The values are different as shown by △Y ₄ . However, the relative positional relationship of the black circles is only that a part of the scanning shown in FIG. 2 is specialized to equiangular scanning, and the same configuration can be used to convert and display a standard television display.

As explained above, the present invention is not limited to fan-shaped scanning ultrasonic probes. An object of the present invention is to provide an ultrasonic diagnostic apparatus that can easily convert scanning into standard television scanning even when the scanning density is arbitrarily set and scanning is performed in various formats.

Further, the address converter 25-4 shown in FIG.
The pitch data generation ROM 25-1 and the address converter 25-4' shown in FIG. Once set, any scanning density can be freely and quickly set.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between ultrasound scanning lines of a conventional fan-shaped ultrasound diagnostic device and television scanning lines, and FIG. 2 is a diagram showing the relationship between ultrasound scanning lines and scanning lines of a standard television display in an embodiment of the present invention. FIG. 3 is a block diagram of a fan-shaped scanning ultrasonic diagnostic apparatus according to an embodiment of the present invention, FIG. 4 is a block diagram of the main part of the apparatus of FIG. 3, and FIG. FIG. 6 is a block diagram illustrating another example of the structure of the read address generating section shown in FIG. 6, and is a diagram showing the relationship between ultrasonic scanning lines and standard television scanning lines in still another embodiment of the present invention. 1-9...Ultrasonic scanning line, 1'-7'...Television scanning line, 10...Ultrasonic probe, 13...Transmitter, 18...A-D converter, 21...Main memory Department,
24...Buffer storage unit, 25...Read address generation unit, 25-1...Pitch data generation
ROM, 25-2...Adder, 25-3...Latch, 25-4...Address converter, 25-4'...
...Address converter, 27...Data selector, 2
8...D-A converter, 29...Mixer, 30...
TV monitor.

Claims (1)

[Scope of Claims] 1. A main memory section that stores an ultrasound image signal obtained by scanning an ultrasound beam so that extension lines of ultrasound scanning lines intersect at approximately one point, and a main memory section that stores information in the main memory section.
a readout control circuit for reading out a video signal, and the readout control circuit calculates the reciprocal of the distance from a point corresponding to the substantially one point to each TV scanning line when the TV video signal is displayed on a TV. a first sub-memory unit that outputs an output according to a scanning line; an accumulator that cumulatively adds the reciprocal; and a second sub-memory that stores a read address of the main memory unit that corresponds to the output of the accumulative adder. An ultrasonic diagnostic device comprising: 2. Claim 1, characterized in that the TV video signal is a signal obtained by interpolating information in the main storage, and the second sub-storage has the interpolation means. The ultrasonic diagnostic device described. 3. Ultrasonic diagnosis according to claim 2, characterized in that the read address of the main storage section is specified by the highest output of the cumulative adder and the output of the second sub-storage section. Device.