JPH03155847A - Ultrasonic observing device - Google Patents

Abstract

PURPOSE:To exactly recognize the difference of quality by a state on an image by providing a transmitting means, a receiving means and a storage means for storing a reference wave corresponding to a tissue, and providing an image forming means for forming an image based on a mutual correlation by an arithmetic means with respect to a mutual correlation of a receiving chirp signal and the reference wave. CONSTITUTION:By a control circuit 13, a relay 11 is switched at every frame. First of all, data of a ROM(1) 8 passes through the relay 11 and applied to a multiplier 12 corresponding to each tap of a delay line 7, multiplied by a voltage of each part of a receiving chirp wave, added by an adder 15, and a mutual correlation of the receiving chirp wave and a reference wave is derived. An output of the adder 15 is stored in a DSC 17 from an A/D converter 16. The control circuit 13 connects the DSC 17 and a frame memory A 19 by controlling a relay 18 and scan-converts an image onto the frame memory A 19. In the same way, the image is scan-converted onto a frame memory B 20 and a frame memory C 21. In such a way, the image is display simultaneously on monitored 22-24.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to an ultrasonic observation device that makes it possible to recognize differences in properties depending on tissues. [Prior Art 1] Conventionally, there are ultrasonic observation devices that use ultrasonic waves to diagnose tissues, organs, etc. inside the body. Recently, ultrasound endoscopes have also been used that allow observation from within a body cavity by endoscopically inserting a probe into the body cavity. By the way, conventionally, diagnosis of tissue properties using an ultrasonic observation device has been performed while looking at the shading of a diagnostic image. However, such a diagnosis requires advanced knowledge and experience, and in order to make a more accurate diagnosis, it is necessary to cut out and examine the tissue of the subject. To deal with this, Japanese Patent Application Laid-Open No. 61-244332 discloses an apparatus that creates a histogram based on received echoes and makes it possible to determine tissue properties from differences in histogram data due to tissue differences. There is. [Problems to be Solved by the Invention] However, the device described above is capable of detecting tissues based on differences in data obtained by forming a histogram of luminance on an image after linearly amplifying a received echo, amplifying it by 100, and A/D converting it. Although it is used to know the properties, there is a problem in that it is difficult to obtain subtle differences in brightness depending on the tissue from the histogram. The present invention has been made in view of the above circumstances, and allows us to accurately identify differences in properties depending on the tissue on an image! ! The purpose of this project is to provide an ultrasonic observation device that can be used to detect [Means for Solving Problem 1] The ultrasonic observation device of the present invention includes a transmitting means for transmitting a chirp-wave ultrasonic wave toward a tissue, and a receiving means for receiving an echo from the tissue to obtain a received chirp signal. , storage means for storing a reference wave according to the tissue, calculation means for calculating the cross-correlation between the received chirp signal obtained by the reception means and the reference wave stored in the storage means, and the calculation means and an image forming means for forming an image based on the cross-correlation calculated by. [Operation] In the present invention, a chirp wave ultrasonic wave is transmitted toward the tissue by the transmitting means, and an echo from the tissue is received by the receiving means to obtain a received chirp signal. The calculating means calculates the cross-correlation between the received chirp signal and the reference wave stored in the storage means, and the image forming means forms an image based on the cross-correlation. [Example] Hereinafter, the present invention will be described in detail with reference to the drawings. FIGS. 1 to 4 relate to a first embodiment of the present invention.
The figure is a block diagram showing the configuration of the ultrasonic observation device, Figure 2 is a waveform diagram showing the transmitted chirp wave, Figure 3 is a waveform diagram showing the received chirp wave, and Figure 4 is the correlation between the received chirp wave and the reference wave. It is a waveform diagram which shows a subsequent waveform. As shown in Figure 1, the ultrasonic observation device
11, an image processing device 2 to which this ultrasonic gift 1t1 is connected, and three monitors 22, 23, and 24 connected to this image processing device 2. The ultrasonic endoscope 1 has an elongated and flexible insertion section 41, and an operation section 42 is provided at the rear end of the insertion section 41. Although not shown, the distal end of the insertion section 41 is provided with an illumination window and an observation window. A light distribution lens is provided inside the illumination window, and a light guide is connected to the rear end of the light distribution lens. This light guide has an insertion section 41. It is inserted through the operating section 42 and a universal cord (not shown) and connected to a light source device (not shown). Illumination light from the light source device is irradiated onto the subject through the light guide and the light distribution lens. Further, an objective lens system is provided inside the observation window, and the front end surface of the image guide is disposed at the imaging position of the objective lens system. This image guide is for insertion section 4.
1 and the operating section 42, and extends to an eyepiece section (not shown) provided at the rear end of the operating section 42. The object image formed by the objective lens system is guided to an eyepiece by an image guide, and is observed from the eyepiece. In addition, instead of the image guide and eyepiece section, a COD is installed at the imaging position of the objective lens system.
It is also possible to provide a solid-state image pickup device such as a solid-state image pickup device, and use this solid-state stone image device to capture an image of the subject and display it on a monitor. Furthermore, the ultrasonic transducer 3 is rotatably provided at the distal end of the insertion section 41 so as to radially scan the inside of the body. A cable 4 is connected to this vibrator 3,
This cable 4 is connected to the image processing device 2. In the image processing device 2, a transmitting circuit 5 connected to the vibrator 3 via the cable 4 and a signal processing circuit 6 are provided. The output of the signal processing circuit 6 is input to a delay line 7. This delay line 7 has a plurality of taps each having a different delay m, and the delays m of each tap are equally spaced in time. The output of each tap of the delay line 7 is applied to a multiplier 12, respectively. Furthermore, the first
In the figure, only the multiplier corresponding to one tap is shown. Also, R○M (read only memory) that stores reference waves corresponding to each tissue (1) 8. ROM(2)9. ROM
(3) 10 are provided. One of the data in the ROMs 8 to 10 is selected by a relay 11 with three inputs and one output, and the multiplication is applied to a multiplier 12. Although only one relay 11 is shown in FIG. 1, a plurality of relays 11 are provided in each layer corresponding to the calculators 12. The relay 11 is configured to be switched by a control circuit 13. The operation of the control circuit 13 is started by a switch 14. A calculator 12 in each layer multiplies the output of the delay line 7 and the data of the selected ROM. Each layer 12
The output of is added t1 at addition rJZ15, and each addition
The output is converted into a digital signal by an A/D converter 16 and input to a DSC (digital scan converter) 17. The output of this 08C17 is applied to the input end of a relay 18 which is controlled by a control circuit 13 and has three outputs for one person. Each output terminal of this relay 18 has a frame memory A.
19. Frame memory B20. A frame memory C21 is connected. This frame memory 19.20.21
Each output is sent to the monitor A22. Monitor B23.
The information is input to the monitor 024. Next, the operation of this embodiment will be explained with reference to FIGS. 2 to 4. The transmitting circuit 5 generates a chirp waveform as shown in FIG. The frequency of this chirp waveform changes linearly, for example, from a low frequency fL to a high frequency fH during a sweep time T. The frequency sweep width is Δf-fH-fL. Consider the case where this chirp wave is applied to fat, muscle, etc. The absorption coefficients of fat and muscle are 0.051 nel)
er/Cm, muscle 0.1 neper/cm, which is very different. Also, the speed of sound is 1476 m/s for fat and 156 m/s for muscle.
It differs by about 6% from 8m/s. As described above, since fat and muscle have different absorption coefficients, sound speeds, etc., even if the same chirp waveform is transmitted, the received chirp waveforms will be significantly different as shown in FIG. 3. FIG. 3(a) shows a received chirp wave corresponding to muscle, and FIG. 3(b) shows a received chirp wave corresponding to fat. By the way, as used in pulse compression, when the correlation between two chirp waves is high, the peak of the waveform after cross-correlation becomes large, and when the correlation is low, the peak of the waveform after cross-correlation becomes small. . Therefore, for example, a reference wave is created based on the received chirp wave data actually received from each muscle, the reference wave is multiplied by the received chirp wave corresponding to the muscle, and the cross-correlation is calculated.The waveform is as follows. As shown in FIG. 4(a), the peak becomes higher. On the other hand, when cross-correlation is taken with the received chive waveform corresponding to fat and the reference wave of meat, the peak becomes lower as shown in FIG. 4(b). In this way, the waveform after correlation has a large peak when the correlation is high, as shown in FIG. 4(a), and a small peak when the correlation is low, as shown in FIG. 4(b). Therefore, by cross-correlating the received chirp wave with the reference wave corresponding to each tissue, it is possible to determine which tissue the received chirp wave corresponds to. In this embodiment, this principle is applied. A transmission chirp wave as shown in FIG. 2 generated by the transmission circuit 5 is sent to the vibrator 4, and is emitted from the vibrator 4 as an ultrasonic wave toward the living tissue. In addition, the vibrator 3 is
For example, it is rotated to perform mechanical radial scanning. The echo from the tissue is received by the mole generator 4 and a received chirp wave is obtained. This received chirp wave passes through the signal processing circuit 6 and is input to the delay liner. The delay amount of each tap of this delay line 7 is at equal intervals in time, and the receiving channel

[The j-wave is sampled at the time interval between its taps. A voltage corresponding to each part of the received chirp wave appears from each tap, and each layer is applied to the calculator 12. In this embodiment, the ROM (1) 8 stores the received waveform of the transmitted chirp wave applied to the muscle tissue as a reference wave. Similarly, the ROM (2) 9 stores the received waveform of fat tissue as a reference wave, and the ROM (3) 10 stores the received waveform of the key tissue as a reference wave. When the switch 14 is turned on, the control circuit 13 operates and switches the relay 11 for each frame. First, the data in the ROM (1) 8 passes through the relay 11, and the multipliers corresponding to each tap of the delay line 7 are applied to the calculator 12, where the voltages and multipliers of each part of the received chirp wave are summed. In this way, the received chirp wave and the reference wave are multiplied, and a correlated waveform as shown in FIG. 4 is created. The outputs of each multiplier 12 are added by an adder 15. That is, the cross-correlation between the received wave 11 and the reference wave is determined. The output of the adder 15 is converted into a digital signal by an A/D converter 16 and stored in the DSCl 7. Here, when the reference wave of ROM (1) 8 is selected, the control circuit 13 controls the relay 18 to connect the DSCl 7 and the frame memory A 19. And DSCl
8 scans and converts the image onto the frame memory A19. In this way, the frame memory A19 stores one screen with high brightness on the image of a portion highly correlated with the muscle tissue reference wave.
After the frame is created, this screen is displayed on the monitor A22. Similarly, in the next frame, control circuit 13 controls relay 1
1.18 ROM (2) 9 and frame memory B20
Select. As a result, the multiplication is 1, and the multiplication is done by the calculator 12 in the ROM (
2) The reference wave data of 9 is multiplied by the received chirp wave to create a waveform as shown in FIG. Each multiplication is a calculator 1
The output of 5 is converted into a digital signal by the A/D converter 16, and the image is scan-converted onto the frame memory B20 by the DSCl7.
One frame of the screen with high brightness on the image of the part highly correlated with the adipose tissue reference wave is created, and this screen is displayed on monitor B.
It will be shown on the 23rd. Furthermore, in the next frame, the 1IIJ control circuit 13 selects the ROM (3) 10 and the frame memory C21 using the relay 11.18. As a result, the multiplication is RO in the calculator 12.
The reference wave data of M(3) 10 and the received chirp wave are multiplied, and the output of each multiplier 15 is converted into a digital signal by the A/D converter 16, and by the DSCl 7,
The image is scan-converted onto the frame memory C21, one frame screen is created in the frame memory C21 where the brightness of the part of the image that is highly correlated with the reference wave of the frog tissue is old, and this screen is displayed on the monitor C24. . As described above, images showing areas highly correlated with muscle, fat, and IL tissues are simultaneously displayed on each monitor 22, 23, and 24. As described above, according to this embodiment, the surgeon can monitor the monitors 22 to 2.
By comparing the brightness of multiple screens displayed simultaneously, it is possible to accurately recognize and diagnose differences in tissue properties, making it possible to diagnose the properties of a patient's diseased tissue without cutting out the tissue of the patient. It can be carried out. Furthermore, by reflecting the transmitted chirp wave on mucous membrane tissue, cancerous tissue, etc., and creating a reference wave using the received signal, diagnosis of cancer, etc. becomes possible. In addition, by creating a reference wave for bilirubin gallstones and phosphate gallstones, it becomes possible to diagnose gallstone ladders and determine the type of gallstone dissolving agent to be administered. While conventional ultrasonic diagnosis is merely a morphological diagnosis, this embodiment has a great effect in that it enables qualitative diagnosis as described above. In this embodiment, there are three ROMs and three frame memories each, but any number of these may be provided depending on the type of tissue to be identified. Further, the ROM may be replaceable. FIG. 5 is a block diagram showing the configuration of an ultrasonic observation apparatus according to a second embodiment of the present invention. In this embodiment, a buffer 25 is connected to each tap of the delay line 7 in the first embodiment. The output end of each buffer 25 is connected to the input end of the relay 11 via a resistor string 26 as shown below. Rinawara, the buffer connected to the first tap? The output end of 25 is
It is connected to the first input terminal of the relay 11 through the resistor 51a, and connected to the second input terminal of the relay 11 through the resistor 51b, and also connected to the third input terminal of the relay 11 through the resistor 51c. connected to the end. Similarly, the output terminal of the buffer 25 connected to the second tap is a resistor 52a,
The output terminal of the buffer 25, which is connected to each input terminal of the relay 11 via resistors 52b and 52c and connected to the third tap, is connected to each input terminal of the relay 11 via resistors 53a, 53b and 53c. There is. Although only three taps are shown in Figure 5, in reality there are many taps.
A buffer 25 and three resistors are connected to each tap. The output terminal of the relay 11 has a Ti current-voltage (I-V
) is connected to the A/D converter 16 via a converter 27. In this way, in this embodiment, the ROMs 8 to 10 of the first embodiment are
The other configurations are the same as in the first embodiment, except that the adder 15 is replaced with a buffer 25 and a resistor string 26, and the adder 15 is replaced with an IV transformer 27. Next, the operation of this embodiment will be explained. The input terminal of the relay 11 is switched every frame, and the first
In the frame , the output end of each buffer 25 is connected to the IV converter 27 via resistors 51a, 52a, and 53a, respectively. Therefore, depending on the output voltage of each buffer 25, the resistor 51a. The currents flowing through 52a and 53a are manipulated and converted into voltage by the IV converter 27. Similarly, in the next frame, the output terminals of each buffer 25 are connected to the resistors 51b and 51b, respectively.
It is connected to the IV converter 27 via 52b and 53b, and resistors 51b and 52 are connected depending on the output voltage of each buffer 25.
b, l flowing to 53b! The current is added to the I-V converter 2
7, it is converted to voltage. Furthermore, in the next frame, the output ends of each buffer 25 are connected to resistors 51c and 52, respectively.
c, 53c to the IV converter 27, and resistors 5Ic, 52c,
The currents flowing through 53c are added and converted into voltage by the IV converter 27. When the output voltage of the buffer 25 is 2, the resistance value of the resistor connected to this buffer 25 is R1, and the current flowing through this resistor is I, it is expressed as 1-V.(1/R). Therefore, a set of resistors (51a, 51b, 51c, .), (51b
, 52b, 53b, ...), (51c, 52G
, 53G, . . .) by appropriately setting the reciprocal of each resistance value, a reference wave corresponding to each tissue can be formed. Then, the result of multiplication with this reference wave appears as a current, and the current for each tap is added, and the relay 1
1, and is converted into a voltage by an IV converter 27. In this way, similar to the first embodiment, cross-correlation between the received chirp wave and the reference wave is performed. Other functions and effects are similar to those of the first embodiment. FIG. 6 is a block diagram showing the configuration of an ultrasonic observation apparatus according to a third embodiment of the present invention. In this embodiment, as many correlation calculating means as there are types of tissue to be identified are provided for each tap of the delay line 7. That is, three l-toke Fi 312a, 12b, 12c are connected to each tap of the delay line 7 via three buffers y25a, 25b, 25c. Each multiplication calculator 12a, 12b, 12c has a ROM.
(1)8. ROM (2) 9° ROM (3) 10 is connected. The outputs of the multipliers 12a, 12b, and 12c are input to adders 15a, 15b, and 15c, respectively. Note that FIG. 6 shows only one tap of the delay line 7, which is the 8-channel tap 315a. In 15b and 15c, the multiplication for each tap is performed by adding the outputs of the multipliers. Each multiplication is the output of the calculators 15a, 15b, 15c, l;t, and the difference, respectively, A/D:l:/converted to a digital signal by the barks 16a, 16b, 16C, and sent to the DSCl 7a, 17b.
, 17c, '7L/- Mme E 1,119. 20.21. The other configurations are the same as in the first embodiment. Next, the operation of this embodiment will be explained. The output of each tap of the delay line 7 is multiplied by three multipliers 12a, 12b, and 12c, and then stored in the ROM (1) 8. ROM
(2)9. ROM (3) 10 (7) Reference wave data and multiplication are calculated. And each joining device 15a, 15b, 15
At step c, the results of the multiplication with each irradiated wave data of each ROM 8.9°10 are added. Each adder 15a, 15b, 1
The output of 5c is A/D:1 inverter 16a,
16b and 16C are converted into digital signals and sent to DSC.
Frame memory 19 via l 7a, 17b, 17c
stored in ゜20.21, each frame memory 19゜20
．． At 21, one frame screen is created in which the images of parts highly correlated with the reference waves of muscle, fat, and stored tissue have high brightness, and this screen is displayed on monitors 22, 23, and 24. In this way, in the first embodiment, the data in each ROM was switched for each frame and the output of each tap of the delay line 7 was multiplied, whereas in this embodiment, the data for each tissue was calculated in one frame. Correlation screening is performed in parallel. When ultrasonic diagnosis is performed using the mechanical radial scan method, the image rate is limited to about 10 frames per second. Now, when tissue diagnosis is performed using three reference waves, in the first embodiment, the limit is 3 frames per second on the image, and the movement of the tissue in the body cannot be followed. On the other hand, according to the present embodiment, the number of times corresponding to the number of reference waves is multiplied by the Korean 6 adder, the A/D
Since a converter and DSC are provided, images corresponding to each tissue can be formed and displayed in the same frame.
It is possible to follow the movement of the tissue. Other functions and effects are similar to those of the first embodiment. 7 and 8 relate to a fourth embodiment of the present invention, FIG. 7 is a block diagram showing the configuration of an ultrasonic observation device, and FIG. 8 is an explanatory diagram for explaining the operation of this embodiment. be. In this embodiment, the frame memory 19 in the first embodiment is
, 20.21 are outputted from color filters A28. Color fill B29. The colors are colored green, red, and yellow by the color filter C30, respectively. The outputs of the color filters 28, 29, and 30 are input to a brightness comparison circuit 31, and input data with high brightness is selected and stored in the frame memory 32. The output of this frame memory 32 is then input to a color monitor 33. The other configurations are the same as in the first embodiment. Next, the operation of this embodiment will be explained. As in the first embodiment, images corresponding to each tissue are scan-converted into frame memories 19, 20, and 21 for each frame. As shown in FIG. 8, the data in each frame memory 19, 20.21 is luminance data expressed in, for example, 64 gradations. Note that the numbers in the frame memories 19, 20, 21 in FIG. 8 indicate brightness. Each piece of data in the frame memories 19, 20, and 21 is colored green, red, and yellow by color filters 28, 29, and 30, and input to the brightness comparison circuit 31. The r4 degree comparison circuit 31 selects the input data with the highest brightness and stores it in the frame memory 32. Therefore, frame memory 32
The data will be colored with a color unique to the frame memories 19, 20 and 21 corresponding to the data with the highest brightness. Then, on the color monitor 33, each part having a high correlation with the reference wave of muscle, fat, and one tissue is displayed in a different color. As described above, according to this embodiment, differences in tissue can be displayed in color in one image, and the distribution of tissue properties on the screen can be accurately diagnosed. Further, in this embodiment, the data in the frame memory 32 at any point or area on the screen may be displayed on the screen or may be displayed as a histogram. Note that the present invention is not limited to the above-mentioned embodiments, and, for example, normal ultrasound images similar to conventional ones may also be displayed at the same time. In addition, the images obtained by cross-correlation may be normalized to eliminate the influence of brightness differences other than differences in tissue properties by performing inter-image calculations between the normal ultrasound image and the image obtained by cross-correlation. . Further, image processing such as contour enhancement may be performed on the image obtained by cross-correlation. Alternatively, only one reference wave may be prepared and a specific tissue corresponding to the reference wave may be extracted on the image. Furthermore, the present invention is applicable to various ultrahigh wave observation devices other than ultrasonic endoscopes. [Effects of the Invention] As explained above, according to the present invention, by forming an image based on the cross-correlation between a received chirp signal and a reference wave according to the tissue, it is possible to accurately identify differences in properties depending on the tissue on the image. This has the effect of making it recognizable.

[Brief explanation of the drawing]

FIGS. 1 to 4 relate to a first embodiment of the present invention.
The figure is a block diagram showing the configuration of the ultrasonic observation device, Figure 2 is a waveform diagram showing the transmitted chirp wave, Figure 3 is a waveform diagram showing the received chirp wave, and Figure 4 is the correlation between the received chirp wave and the reference wave. FIG. 5 is a block diagram showing the configuration of the ultrasonic observation device according to the second embodiment of the present invention, and FIG. 6 is a waveform diagram showing the configuration of the ultrasonic observation device according to the third embodiment of the present invention. The block diagrams shown in FIGS. 7 and 8 relate to the fourth embodiment of the present invention,
Figure 7 is a block diagram showing the configuration of the ultrasonic observation device, Figure 8
The figure is an explanatory diagram for explaining the operation of this embodiment. 1... Ultrasound endoscope 2... Image processing device 3...
・Ultrasonic transducer 5... Transmission circuit 6... Delay line 8.9.10-ROM 12... Multiplication calculator 15... Adder 17...
DSC 19, 20, 21...Frame memory 22.23.2
4...Monitor (a) (a) Fig. 2 Fig. 3 Fig. 4 Fig. 4 (b) (b) Fig. 8

Claims (1)

[Scope of Claims] Transmitting means for transmitting chirp wave ultrasound toward tissue; receiving means for receiving echoes from the tissue to obtain received chirp signals; and storage means for storing reference waves corresponding to the tissue. and a calculation means for calculating a cross-correlation between the received chirp signal obtained by the reception means and a reference wave stored in the storage means, and an image forming unit for forming an image based on the cross-correlation calculated by the calculation means. An ultrasonic observation device characterized by comprising: means.