JP2000300555A - Ultrasonic image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an ultrasonic image by which a blood running condition in its vessel can be expressed in a three-dimensional manner. SOLUTION: A voxel space 100 is sliced into a plurality of blocks to execute a predetermined operation for each block. An intermediate image 102 is generated to show a blood vessel only for each block. The intermedium images 102 are superposed giving priority to the ones closer to a viewpoint side while being weighed by a depth queuing method. By doing this, a superposed image 104 is formed. By matching a vision with the direction of an ultrasonic beam, the processing becomes faster, and in this case, an inversely binarizing or a depth queuing processing can be executed for each unit of vision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ultrasonic image processing apparatus, and more particularly to an apparatus for forming an ultrasonic image having a three-dimensional representation.

[0002]

2. Description of the Related Art An apparatus that transmits and receives ultrasonic waves to and from a three-dimensional region in a living body and forms a three-dimensional image based on three-dimensional echo data obtained by the ultrasonic wave has been put to practical use. In such an apparatus, for example, a virtual viewpoint is set on one side of a three-dimensional area, a virtual screen is set on the other side, and echo data is sequentially integrated along each line of sight coming out of the viewpoint. Then, a process of setting the integrated value as a pixel value on the screen is executed. This is a process according to the integration method. In the apparatus described in Japanese Patent Application Laid-Open No. H10-33538, each echo data is sequentially referred to along an echo data sequence acquired on each ultrasonic beam based on a volume rendering method, and a predetermined amount of transmitted light is obtained. Are sequentially calculated to calculate the final output light quantity, that is, the pixel value.

In any case, in the conventional three-dimensional image processing method, basically, the entire three-dimensional area is collectively set as a processing range, and each echo data is obtained until a predetermined calculation end condition is satisfied for each line of sight. Are sequentially performed.

[0004]

In the case where blood vessels existing in a living body are extracted and displayed three-dimensionally,
A three-dimensional image can also be formed using Doppler information (velocity information) of the blood flow. However, in order to secure the accuracy of the Doppler information, transmission and reception must be performed a plurality of times in one direction, and there is a problem that it takes too much time to construct an image. On the other hand, it is also possible to three-dimensionally display the state of the blood vessel on the basis of the level of the echo data, but if the above-described integration method or volume rendering method is simply applied, the entire three-dimensional region is processed, There is a problem that information of real tissue becomes more dominant than blood vessels. For example, in a situation where there is not much difference between the echo intensities of the blood vessel and the real tissue, as shown in FIG. 1A, when the three-dimensional data acquisition probe 8 is used to acquire three-dimensional echo data. When the calculation based on the integration or the volume rendering method is performed along the beam direction B, as shown in FIG.
Is very small. As a result, it is difficult to clearly express the running state of the blood vessel existing in the three-dimensional space even if it is imaged.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to clearly express an image of a tissue (for example, a blood vessel in a liver) having a small luminance difference from surrounding tissues.

[0006]

(1) In order to achieve the above object, the present invention provides an ultrasonic image in which a plurality of lines of sight are set in a data acquisition space and a pixel value is determined for each line of sight. A processing unit that divides each line of sight into a plurality of sections by slicing the data capture space into a plurality of blocks from a viewpoint side, and a unit that performs a predetermined data calculation in a section unit for each of the sight lines And a tissue extraction unit that determines a section in which an operation result that satisfies a tissue extraction condition is first obtained as a visualization section when viewed from the viewpoint side, and determines a pixel value of the line of sight according to the depth of the visualization section. And a synthesizing means for forming an ultrasonic image.

[0007] According to the above configuration, the data capture space as a three-dimensional space is sliced into a plurality of blocks, and the processing is executed for each block. Specifically, a predetermined calculation is performed on the echo data for each line of sight in each block, and the calculation is performed until a section (visualization section) that satisfies a predetermined tissue extraction condition is basically found for each line of sight. Be executed.

For example, the calculation is performed from the first section, and if the tissue extraction condition is satisfied in the predetermined section, the section is regarded as a visualization section, and the calculation for the subsequent sections on the same line of sight can be omitted. is there. here,
If the tissue extraction condition is not satisfied even if the calculation is advanced to the final section, the line of sight may be treated as if there is no visualization section, or a pixel value may be assigned under an appropriate condition.

When the visualization section is specified for each line of sight,
A pixel value is assigned to each line of sight according to the depth of each visualization section from the viewpoint. For example, a line of sight having a visualization section at a shallow position is given greater brightness,
A smaller luminance is given to a line of sight having a visualization section at a deep position. According to such a depth queuing method, a tissue in a living body can be three-dimensionally represented by shading.

[0010] According to the present invention, since the tissue located in front of the viewpoint can be emphasized and expressed with priority, for example, the running state of the blood vessel can be clearly expressed. In particular, even when the luminance difference between tissues is small, the echo data can be integrated and evaluated for each block (for each section) based on the integration method or volume rendering method.
The luminance difference can be more reliably discriminated. In addition, since the echo data is not integrated and evaluated uniformly over the entire data capturing space (the entire line of sight), a problem that a specific tissue is buried in a certain tissue can be solved.

Although the line of sight may be set at an arbitrary position, if the ultrasonic beam direction is matched with the line of sight, the advantage is that the above processing can be applied as it is in the chronological order of the echo data. Can be obtained. Therefore, real-time display becomes possible.

Preferably, the tissue extraction means performs a predetermined operation on the data in the section for each section, and a binarization processing which performs a binarization process on a calculation result of the calculation means. Means for determining whether the section is a visualization section based on the value after the binarization.

According to the above configuration, the calculation result is evaluated by discrimination based on the threshold value. That is, it is possible to determine whether the organization is the target organization.

Preferably, the calculation means executes a calculation according to a volume rendering method. Preferably, the calculation means executes a calculation according to an integration method.
Preferably, in the binarization processing, inversion binarization of data is performed based on a threshold value. For example, when extracting a blood vessel in an organ, the blood vessel echo is determined to be smaller than the organ echo, and it is desirable to perform inversion binarization processing.
That is, the smaller one is extracted using the luminance difference.

Preferably, a means for variably setting the threshold value is included. According to this variable threshold value, the extraction target can be set freely. Further, appropriate observation conditions can be set according to the constitution and the observation site.

Preferably, the apparatus further comprises means for variably setting a depth width of the block. According to experiments, the depth width of the block is preferably set to, for example, 10 to 20 data when expressing a blood vessel, but is more desirably configured to be appropriately changed according to an observation target or the like.

(2) In order to achieve the above object, the present invention provides an intermediate image generating means for slicing a data capture space into a plurality of blocks from the viewpoint side and forming an intermediate image for each block; It is characterized by including a synthesizing unit that synthesizes the intermediate image according to a predetermined condition while performing weighting according to the order from the viewpoint side, and a display unit that displays the ultrasonic image after the synthesis.

According to the above arrangement, an intermediate image is formed for each block in order to make the tissue structure in each block more apparent, instead of imaging the data capture space all at once. The composition is performed on the premise of weighting according to the depth.

Preferably, the intermediate image generating means performs a predetermined data calculation for each line of sight passing through the plurality of blocks, and a calculation result of the calculation means using a predetermined threshold value. Binarizing means for generating an intermediate image by inverting binarization.

Preferably, the synthesizing means weights the binarized intermediate image for each line of sight in accordance with the depth from the viewpoint, and the plurality of intermediate images for each line of sight. A pixel value determining unit that extracts the largest weight value in the image and uses the extracted value as the pixel value of each line of sight.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIGS. 2 and 3 show the basic principle of the image processing method according to the present embodiment. In the present embodiment, as shown in FIG. 3, the voxel space 100 is sliced by a plurality of blocks. Here, each block is set so as to pass through a plurality of lines of sight coming out of the viewpoint. The voxel space 100 is a space formed by a probe for capturing three-dimensional echo data, that is, a three-dimensional space formed by three-dimensionally scanning an ultrasonic beam. In the present embodiment, a scanning surface is formed by electronically scanning the array transducer as described later, and the voxel space 100 is formed by mechanically moving the scanning surface in a direction orthogonal to the scanning surface. That is, the voxel space 100 is a space constituted by three-dimensional echo data captured in the three-dimensional space.

Incidentally, in FIG. 3, the X direction corresponds to the electronic scanning direction, the Y direction corresponds to the mechanical scanning direction for moving the scanning surface, and the Z direction corresponds to the ultrasonic beam direction, that is, the depth direction. Is equivalent. If the line-of-sight direction is made to coincide with the beam direction, real-time image processing can be performed as described later in detail. Of course, the viewpoint may be arbitrarily set independently of the direction of the ultrasonic beam. In any case, a plurality of blocks are defined so as to intersect with each line of sight from the viewpoint side.

FIG. 2A shows a specific scanning plane in the voxel space 100. Here, the scanning surface corresponds to a B-mode image.

As described above, the voxel space 100 is divided by a plurality of blocks, and as a result, each line of sight is divided into a plurality of sections. In the present embodiment, the beam direction and the line-of-sight direction match, and more specifically, the beam is divided by a specific beam B or a plurality of sections W. And
A predetermined operation is performed for each section W.

Here, the calculation is performed according to Japanese Patent Laid-Open No. Hei 10-335.
It is preferable that the calculation is an operation based on the volume rendering method described in Japanese Patent Publication No. 38 or the like or an integration operation. That is, in this method, the echo data is sequentially referred to from the viewpoint side in each section, and all the echo data in the section are integrated to obtain a calculation result. Of course, various calculation methods can be applied.

FIG. 2B shows the calculation results for each block. (B1) shows the operation result in block 1, and similarly (B2), (B2)
3) and (B4) show the calculation results of block 2, block 3 and block 4, respectively. As shown in (B), for example, in the block 2 including the blood vessel 10, the calculation result is largely open between the blood vessel portion and the real tissue 12. That is, it is understood that discrimination of blood vessels can be performed more accurately. Here, the symbol D shown in (B2) represents the difference between the calculation results of the real tissue 12 and the blood vessel 10. Conventionally, since there is no concept such as a block or a section, volume rendering and integration are performed over the entire line of sight, and therefore, echo data of a blood vessel part has been evaluated relatively low. According to this, as shown in (B2), by subdividing the calculation range of a block, it is possible to more accurately recognize a target tissue that exists locally.

In the present embodiment, the operation result of each section is subjected to an inversion binarization process using a predetermined threshold value, and the operation result exceeding the threshold value is converted to the lowest luminance. , The operation result not exceeding the threshold value is converted to the highest luminance. As a result, in the example shown in FIG. 2, the highest luminance is given to the part where the blood vessel exists.

When the above-described decision binarization processing is executed for each block, an intermediate image 102 after inversion binarization is generated for each block as shown in FIG. That is, the intermediate image 102 is positioned as an image representing a blood vessel included in each block. In the present embodiment, a weighting process corresponding to the depth when each block is viewed from the viewpoint, that is, a depth queuing process, is performed on the intermediate image 102, and the intermediate image 102 is located in front of the intermediate image 102 when viewed from the viewpoint side. The synthesis process of the plurality of intermediate images is executed while selecting the weight value to be performed. As a result, a composite image 104 is obtained.

Therefore, in the composite image 104, a density value is assigned according to the depth of the block in which the blood vessel exists, and a plurality of blood vessels traveling three-dimensionally are three-dimensionally expressed. Become. Here, since the synthesis is performed with priority given to the near side when creating the synthesized image, the blood vessels existing on the back side are basically deleted. In this case, it is possible to omit the operation for such a portion to be erased in advance.

As described above, according to the present embodiment, the blood vessels existing in three dimensions can be expressed in three-dimensional density while giving priority to the blood vessels existing in the foreground when viewed from the viewpoint side. There is an advantage that the information can be provided. Although a blood vessel is represented in the above example, the above method can be applied to a case where a malignant tumor or the like is three-dimensionally displayed. The composite image 104 can be displayed in black and white shades, but may be colored, for example. In any case, according to this embodiment, since the three-dimensional representation can be finally performed while extracting the target tissue for each block, the difference can be emphasized and expressed even between tissues where the difference in echo intensity is small. There are advantages.

FIG. 4 is a block diagram showing a preferred embodiment of the ultrasonic image processing apparatus according to the present embodiment. This ultrasonic image processing device is an ultrasonic diagnostic device.

The three-dimensional echo data capturing probe 8 is, for example, a probe used in contact with the surface of a living body. An array transducer and a mechanism for mechanically scanning the array transducer are provided inside the probe. The ultrasonic beam is electronically scanned by electronically scanning a plurality of transducers constituting the array transducer, and the voxel space 100 described above can be formed as a result by mechanically scanning the array transducer. It is also possible to use a 2D array transducer in which a plurality of diagnostic elements are two-dimensionally arranged. Further, another probe may be used.

The transmission / reception section 14 supplies a transmission signal to the three-dimensional echo data acquisition probe 8 and processes a reception signal output from the three-dimensional echo data acquisition probe 8. Circuit. The transmitting and receiving unit 14 forms a transmission beam and a reception beam. The scanning and focusing of the beam are controlled by the scanning control unit 16.

The image forming section 18 is a circuit for forming an ultrasonic three-dimensional image by the method shown in FIGS.
The image forming unit 18 may be configured as dedicated hardware, or may be configured by a device such as a computer, for example. The threshold value setting device 20 is a device for variably setting the threshold value shown in FIG. 2 by the user, and the block width setting device 22 sets the depth width (width in the line of sight) of the sliced block by the user. This is a device for variably setting. The setting devices 20 and 22 are configured by input devices such as a keyboard and a trackball. The display unit 24 is configured by a display such as a CRT.

FIG. 7 is a flowchart showing the processing contents in the image forming section 18. Incidentally, in the image forming unit 18 shown in FIG. 4, slightly different from the method shown in FIGS. 2 and 3, the same processing as described above is executed for each beam. That is, instead of performing processing in units of blocks, data processing is performed along a time series in beam units by matching the line of sight to the beam.

In S101, an ultrasonic beam is formed for a specific beam address (azimuth). In S102, 0 is substituted for i indicating the block number, and in S103, a predetermined calculation is performed on the echo data on the ultrasonic beam in the block i (in the section i). The predetermined calculation is, for example, a calculation based on the volume rendering method as described above, or a calculation based on the integration method. By this S103, the calculation result for each section on the beam is obtained.

In step S104, as shown in FIG. 2B, for example, in order to extract only a blood vessel part, an inversion binarization process is performed on the operation result. That is, each calculation result is compared with the threshold value, the calculation result exceeding the threshold value is converted into the lowest luminance, and the echo data below the threshold value is converted into the highest luminance. Of course, if the extracted organ has a higher level than the background organ, it is not necessary to perform the inversion processing.

When the inversion binarization process is performed on the operation result of the section currently being processed, in S105, it is determined whether or not the operation result of the section has been converted to the highest luminance as a result. . Here, if it is determined that the luminance has been converted to the highest luminance, S108 is executed, while if it is determined that the luminance has been converted to the lowest luminance, S10 is executed.
6 is executed. In S106, it is determined whether or not the block number has reached the final number. If not, i is incremented by one in S107, and
Each step from 102 is repeatedly executed. If the highest luminance is determined in S105 during such repeated execution, the process proceeds to S108. Thus, for example, it is possible to omit the calculation after the detection of the blood vessel.

In S108, the number of the section in which the maximum luminance is determined, that is, the block number i is stored in association with the beam address.

In step S109, it is determined whether or not the beam has reached the final beam. If the beam has not reached the beam, the beam address is changed in step S110 to form an ultrasonic beam on a new address. Is done. Then, in S111, pixel values are mapped for each beam address, that is, for each line of sight in the present embodiment. Specifically, for example, a pixel value is determined for each line of sight according to a relational expression between i corresponding to the block depth and the pixel value size I as shown in FIG. Thereby, for example, a mapping image 106 as shown in FIG. 5 is configured. That is, a pixel value corresponding to i is given for each line of sight, and a three-dimensional ultrasonic image is constituted by the whole. In S112, such an ultrasonic image is displayed on the display unit 24. Incidentally, as shown in FIG. 6, various relational expressions between i and I can be selectively used as shown by reference numerals 301 and 302, for example.

In the flowchart shown in FIG.
Reference numeral 103 is regarded as including a function as a block dividing unit. Also, S104 and S105
Is also positioned as a tissue extraction means. And S1
11 can be positioned as a combining means. From another point of view, S103 and S104 are positioned as intermediate image generation means. It is desirable to set, for example, 10 to 20 pixels as the depth width of the block.

According to the above embodiment, for example, even when extracting a blood vessel, the Doppler information is not used.
Since the imaging can be performed using the level of the echo data itself, there is an advantage that the calculation speed can be increased, and the state of the blood vessel traveling three-dimensionally can be more clearly expressed.

[0044]

As described above, according to the present invention,
It is possible to clearly express an image of a tissue having a small luminance difference from the surrounding tissue.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a problem of a calculation result based on a conventional method.

FIG. 2 is a diagram for explaining the principle of the present invention.

FIG. 3 is a diagram for explaining the principle of the present invention.

FIG. 4 is a block diagram illustrating an overall configuration of an ultrasonic image processing apparatus according to the present embodiment.

FIG. 5 is an explanatory diagram showing a mapping image.

FIG. 6 is a diagram showing weighting conditions.

FIG. 7 is a flowchart illustrating specific processing contents in an image forming unit.

[Explanation of symbols]

8 Probe for 3D echo data acquisition, 10 blood vessels, 1
2 real organization, 14 transmitting / receiving unit, 16 scanning control unit, 18
Image forming unit, 20 threshold setting unit, 22 block width setting unit, 24 display unit, 100 voxel space, 102
Intermediate image, 104 composite image.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4C301 BB13 BB22 BB28 BB29 EE20 GB02 JB23 JC14 KK17 5B057 AA07 BA05 CA13 CB13 CE08 CE20 DA08 DB03 DB08 5C054 AA01 AA05 CA08 CF05 FC05 FC12 FD01 HA12 5J083 AA19 AB

Claims (10)

[Claims] 1. An ultrasonic image processing apparatus for setting a plurality of lines of sight in a data capture space and determining a pixel value for each line of sight, wherein the data capture space is sliced into a plurality of blocks from a viewpoint side. Dividing means for dividing each line of sight into a plurality of sections, and means for executing predetermined data calculation for each section for each line of sight. A tissue extraction unit that determines the obtained section as a visualization section; and a combining unit that determines a pixel value of the line of sight according to the depth of the visualization section, thereby forming an ultrasound image. Ultrasonic image processing apparatus. 2. The apparatus according to claim 1, wherein the tissue extracting means performs a predetermined operation on data within the section for each section, and binarizes a result of the operation of the calculating means. An ultrasonic image processing apparatus comprising: a binarization processing unit that performs processing; and a determination unit that determines whether the section is a visualization section based on the value after the binarization. 3. An ultrasonic image processing apparatus according to claim 2, wherein said calculation means executes a calculation according to a volume rendering method. 4. The ultrasonic image processing apparatus according to claim 2, wherein said calculation means executes a calculation according to an integration method. 5. The ultrasonic image processing apparatus according to claim 2, wherein in said binarization processing, inversion binarization of data is executed based on a threshold value. 6. The ultrasonic image processing apparatus according to claim 5, further comprising means for variably setting said threshold value. 7. The ultrasonic image processing apparatus according to claim 1, further comprising means for variably setting a depth width of said block. 8. An intermediate image generating means for slicing a data capturing space into a plurality of blocks from the viewpoint side and forming an intermediate image for each block, and for each of the intermediate images according to an order from the viewpoint side. An ultrasonic image processing apparatus comprising: synthesizing means for synthesizing each intermediate image according to predetermined conditions while performing weighting; and display means for displaying the ultrasonic image after the synthesis. 9. The apparatus according to claim 8, wherein the intermediate image generating means performs predetermined data calculation for each line of sight passing through the plurality of blocks, and calculates a calculation result of the calculation means in a predetermined manner. An ultrasonic image processing apparatus, comprising: a binarizing unit configured to generate an intermediate image by performing inversion binarization using a threshold value. 10. The apparatus according to claim 9, wherein the synthesizing unit weights the binarized intermediate image on a line-of-sight basis according to a depth from a viewpoint. An ultrasonic image processing apparatus, comprising: a pixel value determining unit that extracts a largest weight value among the plurality of intermediate images for each line of sight and sets the extracted value as a pixel value of each line of sight.