JP2018157872A - Ultrasonic image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve shielding processing suitable for an ultrasonic image.SOLUTION: An evaluation region 52 is a rectangular region (a cube) around coordinates P corresponding to the depth of a pixel of attention. A shielding ratio calculation part calculates a shielding ratio of the pixel of attention based on a plurality of differential values acquired from a plurality of visual lines 34 passing through the inside of the evaluation region 52 by acquiring a differential value between a depth to a shield portion and a depth to a border of the evaluation region 52 for each visual line 34 passing through the inside of the evaluation region 52. The shielding ratio calculation part calculates the differential value between the depth to the shield portion and the depth to the border of the evaluation region 52 for each visual line 34 passing through the inside of the evaluation region 52 using depth data stored in a depth data storage part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ultrasonic image processing apparatus.

  A typical example of an ultrasonic image processing apparatus that forms an ultrasonic image based on data obtained by transmitting and receiving ultrasonic waves is an ultrasonic diagnostic apparatus. As the ultrasound image, for example, a two-dimensional image such as a B-mode image or a color Doppler image is well known. Also known is an apparatus that forms an ultrasonic image (three-dimensional ultrasonic image) that three-dimensionally displays a tissue or fetus in a living body based on volume data obtained three-dimensionally by transmitting and receiving ultrasonic waves. (For example, refer to Patent Document 1).

  Meanwhile, in the field of computer graphics, an image processing technique called ambient occlusion (environmental shielding) is known (see, for example, Patent Document 2). In ambient occlusion, the influence of ambient light on each pixel is evaluated according to how much each pixel in the image is shielded by the surrounding scene. Ambient occlusion can provide a natural shading effect to the image.

JP 2012-5593 A U.S. Pat. No. 8,878,849

  For example, it is expected that a natural shading effect is also given to an ultrasonic image by using a shielding process (image processing) such as ambient occlusion. However, for example, since the amount of computation for shielding processing such as ambient occlusion is enormous, it is desirable to realize shielding processing suitable for an ultrasound image.

  Therefore, an object of the present invention is to realize a shielding process suitable for an ultrasonic image. For example, it is desirable to realize a shielding process capable of obtaining a natural shadow effect with a relatively small amount of calculation.

  An ultrasonic image processing apparatus suitable as an aspect of the present invention uses the luminance information obtained for each line of sight from a plurality of lines of sight by calculation based on ultrasonic volume data, as the pixel value of each pixel in the image plane, According to the calculation means for obtaining pixel values of a plurality of pixels in the image plane, and each pixel in the image plane as a target pixel, and according to the ratio of the shielding part in the three-dimensional evaluation area at a depth corresponding to the target pixel A means for calculating the degree of occlusion of the target pixel, and for each line of sight passing through the evaluation area, a plurality of values passing through the evaluation area by obtaining a difference value between the depth to the shielding part and the depth to the boundary of the evaluation area. Based on a plurality of difference values obtained from the line of sight, a shielding degree calculating means for calculating a shielding degree of the target pixel and a shielding degree calculated for each pixel with each of the plurality of pixels in the image plane as the target pixel are used. The pixel value of each pixel Based on the pixel value after the shielding process of the plurality of pixels in the image plane and the shielding processing means for obtaining the pixel value after the shielding process of the plurality of pixels in the image plane by correctly setting the pixel value after the shielding process. It has the image formation means which forms an ultrasonic image, It is characterized by the above-mentioned.

  In the above apparatus, a plurality of difference values obtained from a plurality of lines of sight passing through the evaluation region by obtaining a difference value between the depth to the shielding part and the depth to the boundary of the evaluation region for each line of sight passing through the evaluation region. Based on this, the degree of occlusion of the target pixel is calculated. According to the above apparatus, since the degree of shielding is calculated based on the difference value between the depth to the shielding part and the depth to the boundary of the evaluation region, for example, using computation such as spatial integration with a large amount of computation Compared with the case of calculating the shielding degree, the amount of calculation can be greatly reduced. Moreover, in the said apparatus, the pixel value after the shielding process is obtained by correcting the pixel value of each pixel using the shielding degree calculated for each pixel. Thereby, for example, an ultrasonic image having a natural shadow can be formed.

  For example, in the three-dimensional coordinate system including the X axis corresponding to two directions in the image plane, the Y axis, and the Z axis corresponding to the direction of each line of sight, the shielding degree calculating unit It is desirable that a three-dimensional region that extends in the Y-axis direction and the Z-axis direction and surrounds the coordinates corresponding to the target pixel is the evaluation region. The Z-axis direction corresponds to the direction of each line of sight, and a plurality of lines of sight are two-dimensionally arranged in a plane specified by, for example, the X-axis direction and the Y-axis direction. In this configuration, the evaluation area extends in the X-axis direction, the Y-axis direction, and the Z-axis direction, and an evaluation area suitable for the geometrical arrangement of a plurality of lines of sight is realized. In addition, although the preferable specific example of the shape of an evaluation area | region is a rectangular parallelepiped or a cube, it is not limited to these shapes. For example, the evaluation region may have a columnar shape (a cylinder, an elliptical column, a triangular column, a polygonal column) having a height in the Z-axis direction.

  The shielding degree calculation means calculates the difference value as a calculation result in the Z-axis direction for each line of sight passing through the evaluation area, and passes through the evaluation area in a two-dimensional manner in the X-axis direction and the Y-axis direction. It is desirable to calculate the degree of occlusion of the target pixel corresponding to the evaluation region based on a plurality of the difference values obtained as a calculation result in the Z-axis direction from a plurality of lines of sight. According to this configuration, the degree of occlusion of the pixel of interest can be calculated by obtaining a difference value for each line of sight from a plurality of lines of sight passing through the evaluation region. For example, the difference value may be obtained from all the lines of sight that pass through the evaluation area, or the difference value may be obtained from a plurality of lines of sight that are discretely selected from all the lines of sight that pass through the evaluation area. .

  Further, when correcting the pixel value of each pixel using the shielding degree, the shielding processing unit adds a correction according to the magnification ratio of the ultrasonic image, and calculates the pixel value after the shielding process of each pixel. It is desirable to obtain. According to this configuration, the degree of the shielding process can be adjusted according to the magnification rate of the ultrasonic image. For example, it is possible to improve the appearance impression of the ultrasonic image by increasing the degree of shielding as the enlargement ratio increases.

  The ultrasonic image processing apparatus further includes storage means for storing depth data indicating the depth to the shielding portion for each line of sight of the plurality of lines of sight, and the shielding degree calculation means is stored in the storage means. It is desirable to calculate a difference value between the depth to the shielding part and the depth to the boundary of the evaluation region for each line of sight passing through the evaluation region using the obtained depth data. According to this configuration, since the depth difference value can be calculated using the depth data stored in the storage unit, the calculation load on the shielding degree calculation unit is reduced.

  Furthermore, the function corresponding to each part with which the above-mentioned suitable ultrasonic image processing apparatus (including a desirable specific example) is provided may be realized by a computer (including a tablet terminal). For example, the computer described above is preferable by a program that causes a computer to realize the function as the calculation unit, the function as the shielding degree calculation unit, the function as the shielding processing unit, and the function as the image forming unit. It can function as an ultrasonic image processing apparatus. The program may be stored in a computer-readable storage medium such as a disk or a memory, and may be provided to the computer via the storage medium, or may be provided to the computer via an electric communication line such as the Internet. May be provided.

  According to the present invention, a shielding process suitable for an ultrasonic image is realized. For example, according to a preferred aspect of the present invention, by calculating the shielding degree based on the difference value between the depth to the shielding part and the depth to the boundary of the evaluation region, for example, a spatial integration with a large amount of calculation, etc. Compared to the case where the degree of shielding is calculated using calculation, the calculation amount can be greatly reduced. Further, according to a preferred aspect of the present invention, for example, a natural shadow is obtained by correcting the pixel value of each pixel using the shielding degree calculated for each pixel to obtain a pixel value after the shielding process. An ultrasonic image can be formed.

1 is an overall configuration diagram of an ultrasonic diagnostic apparatus that is a preferred specific example of the present invention. It is a figure which shows the specific example of a rendering calculation. It is a figure which shows the specific example of a three-dimensional evaluation area | region. It is a figure for demonstrating the expansion rate of an ultrasonic image.

  FIG. 1 is an overall configuration diagram of an ultrasonic diagnostic apparatus which is a preferred specific example of an ultrasonic image processing apparatus according to the present invention. The probe 10 is an ultrasonic probe for a three-dimensional image, and transmits and receives ultrasonic waves in a three-dimensional space including a diagnostic object such as a fetus. For example, the probe 10 is preferably a two-dimensional array probe (matrix array probe) including a plurality of vibration elements arranged two-dimensionally or a mechanical probe that mechanically moves a plurality of vibration elements arranged one-dimensionally. This is a specific example.

  The transmission / reception unit 12 has functions as a transmission beamformer and a reception beamformer. That is, the transmission / reception unit 12 forms a transmission beam by outputting a transmission signal to each of the plurality of vibration elements included in the probe 10, and further receives a plurality of reception signals obtained from the plurality of vibration elements. A reception beam is formed by performing phasing addition processing or the like.

  In addition, the transmission / reception unit 12 three-dimensionally scans the ultrasonic beam (transmission beam and reception beam) in a three-dimensional space including the diagnosis target. Thereby, ultrasonic reception data is collected from within the three-dimensional space including the diagnosis target.

  The volume construction unit 20 forms volume data corresponding to the three-dimensional space by performing a reconstruction process on the received data obtained from the three-dimensional space. The volume configuration unit 20 performs reconstruction processing such as coordinate conversion processing and interpolation processing on the received data obtained in the scanning coordinate system (for example, rθφ coordinate system), and supports the orthogonal coordinate system (for example, xyz coordinate system). Formed volume data. The volume data is composed of, for example, a plurality of voxel data arranged three-dimensionally in a data space of an orthogonal coordinate system.

  The rendering calculation unit 30 performs a rendering calculation (voxel calculation) based on a plurality of voxel data constituting the volume data.

  FIG. 2 is a diagram illustrating a specific example of the rendering operation. In the rendering calculation (rendering process), a virtual viewpoint for calculation is set outside the volume data 32 corresponding to the three-dimensional space, and a plurality of lines of sight (rays) 34 are formed with respect to the volume data 32 from the viewpoint side. Is set. Further, an arithmetic screen 36 that functions as an image plane is set. In FIG. 2, the screen 36 is illustrated on the opposite side of the viewpoint with the volume data 32 interposed therebetween, but is disposed on the viewpoint side with respect to the volume data 32, and a depth reference that will be described in detail later. It may be a position.

  In the rendering operation, for each line of sight set for the volume data 32, a plurality of voxel data corresponding to the line of sight is processed. For example, a plurality of voxel data corresponding to each line of sight (aligned on each line of sight) is obtained from a plurality of voxel data constituting the volume data 32 by interpolation processing or the like.

  Returning to FIG. 1, the rendering calculation unit 30 sets the luminance information obtained for each line of sight from a plurality of lines of sight by using the luminance rendering calculation to obtain the pixel value of each pixel, so that a plurality of pixels in the screen (image plane) are obtained. Get the pixel value. Thereby, projection image data of luminance information with the screen as the projection plane is formed.

  In luminance rendering processing, for each line of sight, voxel computation based on a rendering method using opacity (opacity) is sequentially performed on a plurality of voxel data (luminance information of voxels) corresponding to the line of sight from the viewpoint side. To be executed. Then, luminance information corresponding to the line of sight is determined for each line of sight as a result of the final voxel calculation, and the luminance information obtained for each line of sight from a plurality of lines of sight is mapped to each pixel in the screen, thereby making the screen Projection image data of luminance information as a projection plane is formed. The projection image data of the luminance information is output to the shielding processing unit 60.

  The rendering calculation unit 30 forms projection image data of depth information in which depth information obtained for each line of sight from a plurality of lines of sight is associated with each pixel. A preferred specific example of the projection image data of depth information is the distance projection image data described in Patent Document 1.

Rendering computer 30, for example by performing a rendering process of a distance which is detailed in the 0023 paragraph etc. of Patent Document 1 calculates the distance D _out for each line of sight of the plurality of line of sight, is calculated for each line of sight by associating that distance D _out to each pixel in the screen (image plane) to obtain the distance projection image data for the screen and the projection plane. The distance D _out is calculated by, for example, Equation 1.

In Equation 1, the distance D _i is the distance of the i-th voxel (i is a natural number) existing on each line of sight, and is calculated from, for example, the voxel pitch in the volume data. A _i is the opacity corresponding to the luminance value of the i-th voxel present on each line of sight, and A _out−1, which is an integrated value of the opacity, is calculated by Equation 2.

The distance D _out calculated by the distance rendering process is obtained by integrating the distances D _i of a plurality of voxels arranged on each line of sight using the opacity A _i , and is the same as the luminance rendering process on the line of sight. Integration ends with the condition (A _out = 1 or the last voxel on the line of sight).

The distance _Dout is an integrated distance from a reference position on each line of sight (for example, a screen position set on the viewpoint side with respect to the volume data), and corresponds to a depth viewed from the reference position side on each line of sight. Therefore, for example, the distance D _out calculated for each line of sight is stored in the depth data storage unit 40 as depth data for each line of sight.

  The shielding processing unit 60 executes shielding processing for giving a shadow effect to the ultrasound image obtained by the rendering operation, for example, projection image data of luminance information that three-dimensionally represents a diagnosis target such as a fetus. In order to obtain a natural shadow effect, it is evaluated how much the attention point in the ultrasonic image is affected by the ambient light, which is light from the surrounding environment. In the evaluation, for example, it is desirable to use the concept of ambient occlusion (environmental shielding).

  Ambient occlusion (environmental occlusion) considers how much the point of interest is occluded by the surrounding environment. That is, the degree of shielding (degree of shielding) at the point of interest is evaluated. A specific example of a numerical value for evaluating the degree of shielding is the shielding rate, which is calculated by the shielding rate calculation unit 50.

  The shielding rate calculation unit 50 uses each pixel in the screen (image plane) as a target pixel, and according to the proportion of the target region in the three-dimensional evaluation region at a depth corresponding to the target pixel, The shielding rate is calculated.

  FIG. 3 is a diagram illustrating a specific example of a three-dimensional evaluation region. FIG. 3 shows a rectangular (cubic) evaluation area 52. In the XYZ coordinate system shown in FIG. 3, the X axis corresponds to the horizontal direction of the screen 36, and the Y axis corresponds to the vertical direction of the screen 36. Further, the Z axis corresponds to the direction of each line of sight 34 orthogonal to the screen 36.

  The evaluation area 52 of the specific example shown in FIG. 3 is a sample whose width in each axial direction of the X axis, the Y axis, and the Z axis is (2K + 1) (K is a natural number) with the coordinate P corresponding to the depth of the target pixel as the center. A rectangular area (cube) corresponding to the point. For example, a total of (2K + 1) × (2K + 1) lines of sight 34 (2K + 1) in the X-axis direction and (2K + 1) in the Y-axis direction pass through the evaluation region 52.

  The shielding rate calculation unit 50 (FIG. 1) obtains a difference value between the depth to the shielding part and the depth to the boundary of the evaluation region 52 for each line of sight 34 that passes through the evaluation region 52. Based on a plurality of difference values obtained from a plurality of lines of sight 34 that pass through, a shielding rate of the target pixel is calculated.

  The shielding rate calculation unit 50 uses the depth data stored in the depth data storage unit 40 (FIG. 1) to determine the depth to the shielding part and the boundary of the evaluation region 52 for each line of sight 34 that passes through the evaluation region 52. The depth difference value is calculated.

The depth data storage unit 40 stores depth data indicating the depth to the shielding part for each line of sight 34. For example, by rendering the distance in rendering computer 30 (FIG. 1), the distance D _out which is calculated for each line of sight 34 is a preferred embodiment of the depth data, the distance D _out is calculated for each line of sight 34 It is the depth to the shielding part.

Based on the depth data stored in the depth data storage unit 40, the shielding rate calculation unit 50 uses, for example, Equation 3 to cover the shielding rate k _A (x, y) of the pixel of interest at the coordinates (x, y). ) Is calculated.

  In Equation 3, z (x + i, y + j) is the depth data of the line of sight 34 that passes through the coordinates (x + i, y + j). z (x, y) is depth data of the line of sight 34 passing through the coordinates (x, y), and corresponds to the depth of the target pixel. Further, (z (x, y) −K) is a depth at a position shallower than the depth z (x, y) of the target pixel by the distance K, and the z coordinate (on the Z axis) of the start surface of the evaluation region 52 Position).

  Further, i of the sample number in the X-axis direction (number for identifying the line of sight as a sample) is a value in the range of −K to + K, and j for the sample number in the Y-axis direction (number for identifying the line of sight as a sample). Is also in the range of -K to + K.

  In the calculation using Equation 3, it is desirable to target all lines of sight 34 that pass through the evaluation area 52. In addition, since the calculation of Formula 3 is to evaluate the ratio (ratio) of the shielding part in the evaluation area 52, it is sampled discretely without targeting all the lines of sight 34 that pass through the evaluation area 52. The calculation may be simplified only for a plurality of lines of sight 34.

  In the calculation using Equation 3, since the depth difference value is used in the Z-axis direction, that is, the line-of-sight direction, the calculation result corresponding to the case where all points (all voxels) arranged in the line-of-sight direction are subject to sampling. Can be obtained.

  The shielding rate calculation unit 50 uses all the pixels in the screen 36 as the target pixel, and calculates the shielding rate for each pixel by using, for example, Equation 3.

  Referring back to FIG. 1, the shielding processing unit 60 shades an ultrasound image obtained by luminance rendering calculation by the rendering calculation unit 30, for example, projection image data of luminance information that three-dimensionally represents a diagnosis target such as a fetus. The shielding process for giving an effect is executed. The shielding processing unit 60 uses the shielding rate calculated for each pixel in the screen by the shielding rate calculation unit 50 to correct the pixel value of the pixel to obtain a pixel value after the shielding process. Pixel values after the shielding process are obtained for all the pixels.

  The shielding processing unit 60 calculates the pixel value (luminance value) after the shielding processing for each pixel in the screen by using, for example, Equation 4.

In Equation 4, I _org (x, y) is a pixel value (luminance value) of the pixel at the coordinate (x, y) in the screen before the shielding process, and k _A (x, y) is a coordinate ( x (y, y) is the shielding rate of the pixel, and I _new (x, y) is the pixel value (luminance value) after the shielding processing of the pixel at coordinates (x, y).

  The shielding processing unit 60 calculates all the pixels in the screen, that is, all the pixels constituting the projection image data of the luminance information, and calculates the pixel value after the shielding processing by, for example, Equation 4 for each pixel.

  The image forming unit 70 forms an ultrasonic image based on the pixel values after the shielding process for a plurality of pixels in the screen. For example, the image forming unit 70 forms an ultrasonic image based on the pixel values (luminance values) after the shielding process for all the pixels constituting the projection image data of the luminance information obtained from the shielding processing unit 60. As a result, for example, an ultrasonic image having a natural shadow effect while three-dimensionally expressing a diagnosis target such as a fetus is formed and displayed on the display unit 72.

  In addition, when correcting the pixel value of each pixel using the shielding ratio, the shielding processing unit 60 performs correction according to the magnification ratio of the ultrasonic image to obtain a pixel value after the shielding processing of the pixel. May be.

  FIG. 4 is a diagram for explaining an enlargement ratio of an ultrasonic image. FIG. 4 shows specific examples of ultrasonic images before and after enlargement. The ultrasonic images before enlargement and after enlargement are images showing the same diagnosis object. For example, an ultrasound image in which the whole body of the fetus is displayed as an image before enlargement is formed, and an ultrasound image in which the same fetus face is greatly projected is formed as an image after enlargement.

The enlargement ratio S is defined as “S = D _L / D _S ”, for example. Here, D _S is the diagnostic object display size before enlargement (e.g. size on the display screen of the display unit 72), D _L is the display size after the enlargement of the same diagnostic object.

  When correction according to the magnification rate S of the ultrasonic image is applied, the shielding processing unit 60 calculates a pixel value (luminance value) after the shielding processing for each pixel in the screen using, for example, Equation 5.

In Equation 5, I _org (x, y) is a pixel value (luminance value) before the shielding process of a pixel at coordinates (x, y) in the screen, and k _A (x, y) is a coordinate ( x is the shielding rate of the pixel located at x), S is the magnification rate, and I _new (x, y) is the pixel value (luminance value) after the shielding process for the pixel located at the coordinates (x, y). .

  By adding a correction according to the enlargement ratio of the ultrasonic image and increasing the darkness of the shielded position in proportion to the display size, for example, the display size can be reduced for the eyes of users such as doctors and laboratory technicians. The larger the size is, the more shadows are shielded, and a shadow effect with a sense of reality can be given.

  Note that the density of the plurality of lines of sight 34 (FIG. 3) may be changed according to the magnification of the ultrasonic image. For example, the density of the plurality of lines of sight 34 may be increased as the enlargement ratio increases. For example, when forming an ultrasonic image in which a fetal face is greatly projected as an enlarged image, a plurality of lines of sight 34 are intensively arranged in a region corresponding to the fetal face. In addition, it is desirable to fix the size of the evaluation region 52 (FIG. 3) in the real space before and after the enlargement of the ultrasonic image, but the size of the evaluation region 52 in the real space may be set as necessary. It may be adjusted.

  Returning to FIG. 1, the control unit 100 generally controls the inside of the ultrasonic diagnostic apparatus in FIG. 1. The overall control by the control unit 100 also reflects an instruction received from a user such as a doctor or a laboratory technician via the operation device 80.

  In the configuration shown in FIG. 1, each of the transmission / reception unit 12, the volume configuration unit 20, the rendering calculation unit 30, the shielding rate calculation unit 50, the shielding processing unit 60, and the image forming unit 70 is, for example, an electric / electronic circuit or a processor It can be realized using hardware, and a device such as a memory may be used as necessary in the realization. Further, at least a part of the functions corresponding to the above-described units may be realized by a computer. That is, at least a part of the functions corresponding to the above-described units may be realized by cooperation between hardware such as a CPU, a processor, and a memory and software (program) that defines the operation of the CPU and the processor.

  The depth data storage unit 40 can be realized by a storage device such as a semiconductor memory or a hard disk drive. A suitable specific example of the display unit 72 is a liquid crystal display, an organic EL (electroluminescence) display, or the like. The operation device 80 can be realized by at least one of a mouse, a keyboard, a trackball, a touch panel, and other switches, for example. And the control part 100 is realizable by cooperation with hardwares, such as CPU, a processor, a memory, and the software (program) which prescribes | regulates operation | movement of CPU, a processor, for example.

  In the configuration shown in FIG. 1, for example, the functions of the rendering calculation unit 30, the shielding rate calculation unit 50, the shielding processing unit 60, and the image forming unit 70 are realized by a computer, and the computer is caused to function as an ultrasonic image processing device. May be.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above is only a mere illustration in all the points, and does not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof.

  DESCRIPTION OF SYMBOLS 10 Probe, 12 Transmission / reception part, 20 Volume structure part, 30 Rendering calculation part, 40 Depth data storage part, 50 Shielding rate calculation part, 60 Shielding process part, 70 Image formation part, 72 Display part, 80 Operation device, 100 Control part .

Claims (5)

Calculating means for obtaining pixel values of a plurality of pixels in the image plane by using luminance information obtained for each line of sight from a plurality of lines of sight by calculation based on ultrasonic volume data; ,
A means for calculating the degree of occlusion of a pixel of interest according to the proportion of the occluded part occupying the three-dimensional evaluation area at a depth corresponding to the pixel of interest, with each pixel in the image plane as the pixel of interest. A pixel of interest based on a plurality of difference values obtained from a plurality of lines of sight passing through the evaluation region by obtaining a difference value between the depth to the shielding part and the depth to the boundary of the evaluation region for each line of sight passing through the inside A shielding degree calculating means for calculating the shielding degree of
By correcting the pixel value of each pixel using the degree of shielding calculated for each pixel with each of the plurality of pixels in the image plane as the target pixel to obtain a pixel value after the shielding process, a plurality of pixels in the image plane are obtained. Shielding processing means for obtaining a pixel value after pixel shielding processing;
An image forming means for forming an ultrasonic image based on pixel values after the shielding processing of a plurality of pixels in the image plane;
Having
An ultrasonic image processing apparatus. The ultrasonic image processing apparatus according to claim 1,
In the three-dimensional coordinate system configured by the X-axis and Y-axis corresponding to two directions in the image plane and the Z-axis corresponding to the direction of each line of sight, the shielding degree calculating means A three-dimensional region that extends in the direction and the Z-axis direction and surrounds the coordinates corresponding to the target pixel is defined as the evaluation region.
An ultrasonic image processing apparatus. The ultrasonic image processing apparatus according to claim 2,
The degree-of-shielding calculation means calculates the difference value as a calculation result in the Z-axis direction for each line of sight passing through the evaluation area, and is arranged two-dimensionally in the X-axis direction and the Y-axis direction through the evaluation area. Based on a plurality of the difference values obtained as a calculation result in the Z-axis direction from a plurality of lines of sight, a degree of occlusion of the target pixel corresponding to the evaluation region is calculated.
An ultrasonic image processing apparatus. The ultrasonic image processing apparatus according to any one of claims 1 to 3,
The shielding processing unit, when correcting the pixel value of each pixel using the shielding degree, adds a correction according to the magnification ratio of the ultrasonic image to obtain a pixel value after the shielding processing of each pixel,
An ultrasonic image processing apparatus. The ultrasonic image processing apparatus according to any one of claims 1 to 4,
Storage means for storing depth data indicating the depth to the shielding part for each line of sight;
The shielding degree calculating means calculates a difference value between the depth to the shielding part and the depth to the boundary of the evaluation area for each line of sight passing through the evaluation area using the depth data stored in the storage means.
An ultrasonic image processing apparatus.