JP4703144B2 - Ultrasonic diagnostic apparatus and image processing method - Google Patents

Description

  The present invention relates to an ultrasound diagnostic apparatus for obtaining ultrasound diagnostic information in a subject by transmitting ultrasound to the subject and receiving a reflected wave from the subject, and an image processing method for generating an ultrasound image About.

  In recent years, in the medical field where diagnosis and treatment are performed, an image created on a medical image diagnosis apparatus such as an ultrasonic diagnosis apparatus, an X-ray CT apparatus, or an MRI apparatus is displayed as a three-dimensional image for diagnosis and treatment. Used for.

  For example, in an ultrasonic diagnostic apparatus, development of a two-dimensional ultrasonic probe that can three-dimensionally transmit and receive an ultrasonic beam to and from a space in a subject is proceeding and is about to enter a practical stage. In this two-dimensional ultrasonic probe, piezoelectric elements that transmit and receive ultrasonic waves are arranged in a matrix (lattice) shape, and the ultrasonic wave is transmitted and received three-dimensionally by scanning, and spreads radially from the surface of the probe. The three-dimensional data is collected. Then, ultrasonic diagnostic information obtained as three-dimensional data is subjected to image processing to generate a three-dimensional image.

  A typical technique for creating a three-dimensional image is volume rendering (hereinafter, sometimes referred to as VR processing). This volume rendering is a three-dimensional display method widely used in medical image diagnostic apparatuses such as X-ray CT apparatuses and MRI apparatuses other than ultrasonic diagnostic apparatuses. In three-dimensional image processing by a medical image diagnostic apparatus such as an ultrasonic diagnostic apparatus, cubic data called voxels is once created from collected three-dimensional image data, and a three-dimensional image is generated based on the voxel data. Note that, in an information processing apparatus that handles three-dimensional image data other than the medical image diagnostic apparatus, the image data is often voxel data.

  In this volume rendering, a predetermined line-of-sight direction (projection direction of projected light) is determined for voxel data, ray tracing processing is performed from an arbitrary viewpoint, and an integrated value of a voxel value (luminance value, etc.) on the line of sight or By outputting the weighted cumulative addition value to the image pixels on the projection plane, the organs and the like are three-dimensionally extracted to generate a three-dimensional image.

  The generation of a three-dimensional image by volume rendering will be described with reference to FIG. An image by volume rendering is obtained by passing a voxel data set 80 through a projection ray 82 having a specific direction based on a specific viewpoint 81 to a pixel 84 projected on a projection plane 83 perpendicular to the projection ray 82. Based on. An integrated value or a weighted cumulative added value is calculated from each voxel value penetrated by the projection light ray 82, and the obtained integrated value or weighted added value is stored in the pixel 84. Finally, a three-dimensional image is generated by collecting a plurality of pixels 84 storing voxel values.

  On the other hand, the operator can arbitrarily set the projection direction of projection light beam 82 (the direction in which voxel data is desired from the viewpoint). The projection ray 82 and the projection plane 83 can be set by a simple equation using the XYZ coordinates in FIG. An image generated by volume rendering is generated by a plurality of pixels 84 projected on the projection surface 83 and finally displayed on a monitor.

  In addition to a three-dimensional image generated by volume rendering, a maximum / minimum-value projection image, an MPR image, or the like is generated from voxel data depending on the application.

  An image generated by calculating a maximum value among the voxel values penetrated by the projection light ray 82 and storing the obtained maximum value in the pixel 84 is referred to as a maximum value projection image. An image generated by calculating the minimum value from the voxel values and storing the obtained minimum value in the pixel 84 is referred to as a minimum value projection image.

  An image generated by a cut surface obtained by cutting voxel data along a specific plane (cut plane) is referred to as an MPR (Multi Plane Reconstruction: MPR) image. The MPR image will be described with reference to FIG. FIG. 15A is a schematic view of the voxel data set 85 cut along a cutting plane 86. FIG. 15B is a schematic diagram showing a cut surface 87 obtained by cutting the voxel data set 85 along the cut plane 86. The pixel on the cutting plane 87 stores the value of the voxel at which the cutting plane 86 intersects the voxel data set 85.

  On the other hand, the operator can set a cutting plane 86 in a three-dimensional space (a space formed by XYZ coordinates). The cutting plane 86 can be set by a simple equation using the XYZ coordinates in FIG.

  Here, a method for generating voxel data will be described. In order to describe a method for generating voxel data in an ultrasonic diagnostic apparatus, first, with reference to FIGS. 16 to 16, image data collection and imaging (eg, Patent Document 1) in an ultrasonic diagnostic apparatus including a one-dimensional ultrasonic probe This will be described with reference to FIG. FIG. 16 is a functional block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to the prior art. FIG. 17 is a diagram for explaining a process of converting into a two-dimensional image in an orthogonal coordinate system. FIG. 18 is a detailed functional block diagram of a digital scan converter (DSC).

  As shown in FIG. 16, a conventional ultrasonic diagnostic apparatus 100 includes a one-dimensional ultrasonic probe 101, a transmission / reception circuit 102, a B-mode processing circuit 103, a CFM (Color Flow Mapping) processing circuit 104, and the like. , A storage device 105, a DSC (Digital Scan Converter) 106, a display device 107, and a controller 108.

  Echo data obtained by the one-dimensional ultrasonic probe 101 is sent to the B-mode processing circuit 103 and the CFM processing circuit 104 via the transmission / reception circuit 102. The B-mode processing circuit 103 visualizes echo amplitude information. The CFM processing circuit 104 visualizes moving blood flow information. Data generated by the B-mode processing circuit 103 is referred to as B-mode ultrasonic raster data, and data generated by the CFM processing circuit 104 is referred to as color ultrasonic raster data.

  The B-mode ultrasound raster data obtained by the B-mode processing circuit 103 and the color ultrasound raster data obtained by the CFM processing circuit 104 are stored in the storage device 105 and sent to the DSC 106. The DSC 106 creates an image to be displayed on the display device 107. The controller 108 controls the operation of the entire ultrasonic diagnostic apparatus.

  The DSC 106 converts ultrasonic raster data into image data represented by orthogonal coordinates in order to obtain an image represented by an orthogonal coordinate system. This conversion process will be described with reference to FIGS.

  The ultrasonic raster data 90 is obtained in a coordinate system expressed by a distance R and an angle θ as shown in FIG. Here, the point O is the center of the surface of the ultrasonic probe 101, and a line perpendicular to the surface of the ultrasonic probe 101 at the point O is defined as the X axis. Further, the Y axis (depth direction) perpendicular to the X axis is set as shown in FIG.

The distance R is the distance between the ultrasonic transmission / reception point (the position of the one-dimensional ultrasonic probe 101) and the ultrasonic sample point 90a, and the angle θ is the swing angle of the ultrasonic beam. The DSC 106 converts the ultrasonic raster data 90 obtained in the (R, θ) coordinate system into image data 91 in an orthogonal coordinate system as shown in FIG. 17B (scan conversion process: SC process). The following relational expression (1) is established between the coordinate system (R, θ) of the ultrasonic raster data 90 and the coordinate system (X, Y) of the image data 91 for display.
Formula (1) R = (x ² + y ² ) ^1/2
θ = arctan (x / y)
The DSC 106 performs the above-described coordinate transformation to create image data 91 represented by a display coordinate system (X, Y).

  Here, the configuration of the DSC 106 will be described with reference to FIG. Under the control of the sequencer 106a, the X coordinate generator 106b and the Y coordinate generator 106c generate position information (X, Y) of image pixels to be generated. A signal indicating the information is sent to the R address converter 106d and the θ address converter 106e, and a coordinate conversion process is performed based on the above equation (1).

  Then, position information indicating R is output from the R address converter 106d, position information indicating θ is output from the θ address converter 106e, and the address converter 106f refers to the storage device 105 from the position information. Address information of the storage device 105 is calculated. Based on this address information, ultrasonic raster data at coordinates (R, θ) is read from the storage device 105. The ultrasonic raster data at the coordinates (R, θ) corresponds to the coordinates (X, Y) after conversion.

  The ultrasonic raster data is input to the interpolation processing circuit 106g, image data for display is generated by the interpolation processing circuit 106g, and an ultrasonic image represented by orthogonal coordinates is displayed on the display device 107. Since ultrasonic raster data is collected discretely, a plurality of ultrasonic raster data is read from the storage device 105, and image data is generated by interpolation processing. In the interpolation processing, for example, linear interpolation processing is performed using surrounding ultrasonic raster data surrounding the coordinate of interest. In this case, the interpolation coefficient is output from the R address converter 106d and the θ address converter 106e to the interpolation processing circuit 106g, and image data is generated by the interpolation processing.

  Next, a case where three-dimensional ultrasonic raster data is collected using a two-dimensional ultrasonic probe and voxel data is created will be described with reference to FIGS. FIG. 19 is a conceptual diagram for explaining that voxel data is generated by scan converter processing. FIG. 20 is a diagram for explaining a process of converting into a three-dimensional image in an orthogonal coordinate system. FIG. 21 is a detailed functional block diagram of a digital scan converter (DSC).

  FIG. 19A shows the geometry of three-dimensional ultrasonic raster data collected using a two-dimensional ultrasonic probe. Point O is the center point of the two-dimensional ultrasonic probe surface, and a line perpendicular to the ultrasonic probe surface at point O is defined as the X axis. Further, a Y axis and a Z axis which are perpendicular to the X axis and perpendicular to each other are set as shown in FIG. Then, scan conversion processing is performed on the ultrasonic raster data, and voxel data 94 represented by an orthogonal coordinate system as shown in FIG. 19B is generated.

This coordinate conversion will be described in detail with reference to FIG. The ultrasonic raster data 93 is obtained in a coordinate system represented by a distance R, an angle θ, and an angle φ as shown in FIG. The distance R, angle θ, and angle φ are defined by definition (1) shown below.
Definition (1)
Distance R: Distance between the ultrasonic transmission / reception point (position of the two-dimensional ultrasonic probe) and the ultrasonic sampling point 93a Angle θ: When the trajectory of the ultrasonic beam is projected on the XY plane, the projected trajectory is the Y axis Angle φ: Angle formed when the trajectory of the ultrasonic beam is projected on the YZ plane and the projected trajectory forms the Y axis

The DSC converts the ultrasonic raster data 93 expressed in the coordinate system (R, θ, φ) into voxel data 94 expressed in the orthogonal coordinate system as shown in FIG. The following relational expression (2) is established between the coordinate system (R, θ, φ) of the ultrasonic raster data and the coordinate system (X, Y, Z) of the voxel data.
Formula (2) R = (x ² + y ² + z ² ) ^1/2
θ = arctan (x / y)
φ = arctan (z / y)
The DSC performs the coordinate conversion described above to create voxel data represented by a coordinate system (X, Y, Z).

  Here, the configuration of the DSC will be described with reference to FIG. The function of each circuit is the same as the DSC shown in FIG. For conversion into voxel data represented in three dimensions, a Z coordinate generator 106h and a φ address converter 106i are provided in addition to the DSC shown in FIG.

  Then, as in the two-dimensional coordinate conversion based on the above equation (2), the coordinates (R, θ, φ) are converted into orthogonal coordinates (X, Y, Z), as shown in FIG. In addition, voxel data 94 expressed in an orthogonal coordinate system is generated. The voxel data is subjected to processing such as volume rendering and maximum / minimum value projection processing to generate an ultrasonic image. Note that since the ultrasonic raster data is collected discretely, when generating voxel data, for example, linear interpolation processing (Tri-Linear interpolation processing) using eight surrounding ultrasonic raster data surrounding the target voxel is performed. Done.

Japanese Patent Laid-Open No. 11-104133 (paragraphs [0021]-[0022], FIG. 3)

  In volume rendering, as shown in FIG. 14, the operator can set the line of sight from an arbitrary direction. However, the conversion from the coordinate system (R, θ, φ) to the orthogonal coordinate system (X, Y, Z) in the conventional scan conversion process is fixed, and the arrangement of the orthogonal coordinates is not arbitrarily set. Not. That is, the Cartesian coordinate system (X, Y, Z) for representing voxel data is fixedly set with respect to the ultrasonic probe, and the X axis is set regardless of the direction of the line of sight (projection direction of the projected ray). It is defined as an axis perpendicular to the ultrasonic probe surface, and the Y axis and the Z axis are defined as axes perpendicular to each other and perpendicular to the X axis.

  When a line of sight is set from a slanting direction with respect to voxel data and projection light rays are advanced at a fixed interval, voxel data does not always exist at each interval, so it is necessary to perform interpolation processing in volume rendering is there. As this interpolation processing, for example, it is necessary to perform linear interpolation processing (Tri-Linear interpolation processing) using eight surrounding voxels surrounding the target voxel.

  As described above, in the conventional ultrasonic diagnostic apparatus and image processing method, in addition to the interpolation processing performed when generating voxel data by DSC scan conversion processing, interpolation is also performed when generating image data by volume rendering. It is necessary to perform processing. Therefore, it is necessary to perform two-stage interpolation processing before generating image data from ultrasonic raster data, but generally there is a problem that the spatial resolution of an image deteriorates as the number of interpolation processing increases. .

  Further, in the conventional scan conversion process, the generation order of voxel data is fixed. For example, as shown in FIG. 22, when the voxel data set 95 is generated in the order shown in the figure (1, 2, 3, 4,...), The voxel data set 95 is close to the projection surface 97 of volume rendering. Generation was later in the entire voxel, and volume rendering could not be started until the scan conversion process was completed. That is, the ray tracing process cannot be performed unless all the voxels located on the predetermined line of sight are generated. Such processing delay greatly impairs the real-time property that is one of the advantages of the ultrasonic diagnostic apparatus.

  Furthermore, the volume rendering is generally processed by software using a personal computer (PC), a workstation or the like. The ultrasonic diagnostic apparatus is required to be portable. However, if a PC or the like is connected to the ultrasonic diagnostic apparatus, the portability is impaired. Also, connection of a PC or the like becomes a factor that greatly increases the power consumption of the entire medical system. For this reason, in order to realize a reduction in size and power consumption of the system, it is desirable to process volume rendering with hardware such as an ASIC. However, it is necessary for the operator to arbitrarily set the line of sight for volume rendering, and in particular, realization with hardware such as ray tracing processing increases the complexity and increases the circuit scale.

  The present invention solves the above-described problems, and allows an orthogonal coordinate system for representing voxel data to be arbitrarily set for an ultrasonic probe, and in particular, one direction of voxel data is parallel to the line-of-sight direction. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that does not need to perform an interpolation process when an ultrasonic image is generated by setting an orthogonal coordinate system to be. An object of the present invention is to improve the spatial resolution by reducing the number of interpolation processes.

  Another object of the present invention is to reduce the load on the CPU (central processing unit) when processing by software by reducing the number of interpolation processes, and to simplify the circuit design when processing by hardware.

  Furthermore, when generating voxel data, an ultrasonic diagnostic apparatus capable of starting the process of generating an ultrasonic image without waiting for the completion of the scan conversion process by setting the generation order to the order along the line-of-sight direction. The purpose is to provide. Accordingly, it is an object of the present invention to improve the efficiency of ultrasonic image generation processing and provide an ultrasonic diagnostic apparatus that does not impair real-time performance.

According to the first aspect of the present invention, an ultrasonic probe that transmits / receives ultrasonic waves to / from a subject, a transmission / reception unit that drives the ultrasonic probe to scan the inside of the subject, and the transmission / reception unit receives the ultrasonic probe A projection direction setting unit that sets a projection position and a projection direction when generating a display image based on a reception signal, and a coordinate system of the projection direction based on a reception signal obtained by scanning of the transmission / reception unit. And voxel data generating means for generating voxel data in the order along the projection direction, and image generating means for generating a display image in the projection direction based on the voxel data. Device.

  A second aspect of the present invention is the ultrasonic diagnostic apparatus according to the first aspect, wherein the voxel data generating means makes the projection direction and one direction of the voxel data parallel to each other. Is.

A third aspect of the present invention is the ultrasonic diagnostic apparatus according to the first or second aspect, wherein the voxel data generation means includes the coordinate system of the projection direction and the collected coordinates where the received signal is received. The voxel data is generated by associating with a system and reading out the received signal in the acquired coordinate system based on the coordinate system in the projection direction .

The invention according to claim 4 is the ultrasonic diagnostic apparatus according to any one of claims 1 to 3, further comprising an input means for receiving an input operation, wherein the projection direction setting means is the input An arbitrary projection position and projection direction are set based on the operation .

The invention according to claim 5 is the ultrasonic diagnostic apparatus according to any one of claims 1 to 4 , further comprising a region-of-interest specifying means for specifying a region of interest in which an ultrasonic image is to be generated. The voxel data generation means generates voxel data based on a received signal in the region of interest .

The invention according to claim 6 is the ultrasonic diagnostic apparatus according to claim 1 , further comprising storage means for storing the received signal in association with the collection coordinate system collected by the transmission / reception means, The voxel data generating means converts a voxel generator that outputs a coordinate system of the projection direction set based on the projection direction, and converts the coordinate system of the projection direction into a three-dimensional orthogonal coordinate system orthogonal to the ultrasound probe. A coordinate converter for converting the converted three-dimensional orthogonal coordinate system to the acquired coordinate system, and storing the received signal based on the acquired coordinate system converted by the coordinate converter To generate the voxel data associated with the coordinate system of the projection direction .

  The ultrasonic probe according to the present invention includes a one-dimensional ultrasonic probe or a two-dimensional ultrasonic probe. When a one-dimensional ultrasonic probe is used, ultrasonic raster data expressed in three dimensions is collected by mechanically moving the probe. When generating voxel data represented by a three-dimensional orthogonal coordinate system from the three-dimensional ultrasonic raster data collected by these ultrasonic probes, the line-of-sight direction (projection direction of the projected ray) and one direction of the voxel data Voxel data is generated so that the line-of-sight direction and the predetermined plane of the voxel data are orthogonal to each other. That is, a three-dimensional orthogonal coordinate system is set so that an arbitrarily set line-of-sight direction and one direction of a three-dimensional orthogonal coordinate system for representing voxel data are parallel, and the voxel data is determined by the three-dimensional coordinate system. Represents.

  A three-dimensional orthogonal coordinate system fixedly set for the ultrasonic probe and a three-dimensional orthogonal coordinate system for expressing voxel data in which the line-of-sight direction and one direction are parallel are, for example, by linear transformation. Correlate. The voxel data generation means obtains a three-dimensional orthogonal coordinate system in which the line-of-sight direction and one direction are parallel based on the relationship of the primary transformation and the vector information of the line-of-sight direction. Represents voxel data. Thus, by performing the coordinate system conversion process, it is possible to make the line-of-sight direction and one direction of the voxel data parallel.

  When the line-of-sight direction and one direction of the voxel data are parallel, for example, when generating a three-dimensional ultrasound image by volume rendering, performing a maximum or minimum value projection process, Interpolation processing is not necessary when generating an MPR image that has been averaged in the thickness direction as a direction, and ray tracing processing becomes relatively easy.

  In addition, in a state where the line-of-sight direction is set obliquely with respect to the voxel data, the setting of the region of interest (calculation for calculating the generation start position and generation end position of the voxel data) becomes complicated. By setting the line-of-sight direction and one direction of voxel data in parallel as in the present invention, the setting of the region of interest is simplified.

Claim 1, claim 2, claim 6,請 Motomeko 7, claim 8, and according to the invention described in claim 12, and one direction of the line-of-sight direction and the voxel data by changing the orientation of the voxel data By making them parallel, an interpolation process for generating an ultrasonic image from voxel data becomes unnecessary, so that the spatial resolution of the ultrasonic image can be improved. In addition, the burden on the CPU in software processing can be reduced, and circuit design in hardware processing can be simplified.

According to the first and seventh aspects of the invention, by generating voxel data in the order along the line-of-sight direction, an ultrasonic image (three-dimensional ultrasonic image, maximum value projection) is generated based on the generated voxel data. Images, etc.) can be generated sequentially. As a result, generation of an ultrasonic image can be started before all the voxel data is generated, so that the time required for image generation can be shortened, and the efficiency of image generation can be improved.

According to the fifth and eleventh aspects of the present invention, it is possible to reduce the number of voxel data processes in the conversion unit and the image generation unit by generating the voxel data based on the received signal in the region of interest. Accordingly, it is possible to generate an image at a high speed. In addition, since the setting of the region of interest is simplified by making the line-of-sight direction and one direction of voxel data parallel, the hardware configuration is simplified and the time required for image generation is shortened compared to the conventional case. It becomes possible to do.

  Hereinafter, an ultrasonic diagnostic apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 13.

[First Embodiment]
An ultrasonic diagnostic apparatus and an image processing method according to a first embodiment of the present invention will be described with reference to FIGS.

(Constitution)
The configuration of the ultrasonic diagnostic apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a functional block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to the first embodiment of the present invention.

  The ultrasonic diagnostic apparatus 1 according to the first embodiment includes a two-dimensional ultrasonic probe 2, a transmission / reception circuit 3, a B-mode processing circuit 4, a CFM processing circuit 5, a storage device 6, a DSC 7, The rendering processing device 8 includes a display device 9, a console 10, a coordinate system setting circuit 11, and a controller 12.

  The two-dimensional ultrasonic probe 2 is configured such that piezoelectric elements that transmit and receive ultrasonic waves are arranged in a matrix (lattice), and the ultrasonic waves are transmitted and received three-dimensionally by scanning, and spread radially from the surface of the probe. Are received as echo signals.

  The transmission / reception circuit 3 supplies an electrical signal to the two-dimensional ultrasonic probe 2 to generate an ultrasonic wave, and receives an echo signal received by the two-dimensional ultrasonic probe 2. The echo signal is output to the B-mode processing circuit 4 or the CFM processing circuit 5 depending on the purpose of processing.

  The B-mode processing circuit 4 visualizes echo amplitude information and generates B-mode ultrasonic raster data from the echo signal. The CFM processing circuit 5 visualizes the moving blood flow information and generates color ultrasonic raster data. Blood flow information includes information such as speed, dispersion, and power, and blood flow information is obtained as binarized information. The ultrasonic raster data is temporarily stored and held in the storage device 6 including a memory.

  The DSC 7 converts the ultrasonic raster data into voxel data represented by orthogonal coordinates in order to obtain an image represented by the orthogonal coordinate system. The detailed configuration and operation of the DSC 7 will be described later. The DSC 7 corresponds to the “voxel data generation means” of the present invention.

  The volume rendering processing circuit 8 performs volume rendering on the voxel data output from the DSC 7 to generate a three-dimensional image. The three-dimensional image created by the volume rendering processing circuit 8 is displayed on a display device 9 made up of a CRT or the like.

  The console 10 includes a keyboard, a mouse, a trackball, and the like. The console 10 is connected to the controller 12 and designates the projection direction (line-of-sight direction) of the projected light beam with respect to the voxel data by the operation of the operator. The console 10 corresponds to the “projection direction setting means” of the present invention. The coordinate system setting circuit 11 receives unit vector information indicating the line-of-sight direction from the console 10 and outputs the information to the DSC 7. Moreover, the controller 12 is connected to each circuit which comprises the ultrasonic diagnosing device 1, and performs those control.

(Operation)
Next, the operation of the ultrasonic diagnostic apparatus according to the first embodiment will be described with reference to FIGS. FIG. 2 is a functional block diagram showing a detailed configuration of a digital scan converter (DSC) provided in the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 3 is a flowchart for sequentially explaining operations of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 4 is a diagram for explaining coordinate conversion processing in DSC. FIG. 5 is a schematic diagram showing a state in which projected light rays and voxel data are aligned on a straight line.

  First, three-dimensional ultrasonic raster data is collected using the two-dimensional ultrasonic probe 2 (step S01). The collected three-dimensional ultrasonic raster data is shown in FIG. The point O is the center point of the surface of the two-dimensional ultrasonic probe 2 and a line perpendicular to the ultrasonic probe surface at the point O is defined as the X axis. Further, a Y axis and a Z axis that are perpendicular to the X axis and are perpendicular to each other are set as shown in FIG. The coordinate system (X, Y, Z) is fixedly set with respect to the two-dimensional ultrasonic probe 2 (the coordinate system (R, θ, φ) for representing the ultrasonic raster data 20). A coordinate system for collecting ultrasonic raster data is a coordinate system (R, θ, φ), and a coordinate system (X, Y, Z) that is an orthogonal coordinate system. The coordinate system (R, θ, φ) corresponds to the “collection coordinate system” of the present invention.

  The DSC 7 receives the coordinate information (X ′, Y ′, Z ′) of the voxel data necessary for generating the voxel data 21 from the ultrasonic raster data 20 shown in FIG. The voxel data 21 is generated so that the projection direction of the projection light beam 22 indicated by an arrow in (b) is parallel to one direction of the voxel data 21 (the projection direction and a predetermined plane of the voxel data 21 are orthogonal). To do. The coordinate system of the voxel data 21 is (X ′, Y ′, Z ′), and FIG. 4C shows the coordinate system (X, Y, Z), the coordinate system (X ′, Y ′, Z ′), and Voxel data 21 is shown. The DSC 7 converts a coordinate system (X ′, Y ′, Z ′) in which the X ′ axis, the Y ′ axis, and the Z ′ axis are orthogonal to a direction in which the direction of the Z ′ axis is parallel to the projection direction of the projection light beam 22. .

  Here, the relationship between the coordinate system (X, Y, Z) and the coordinate system (X ′, Y ′, Z ′) will be specifically described. The coordinate system (X, Y, Z) and the coordinate system (X ′, Y ′, Z ′) are associated with each other so that conversion can be performed by primary conversion based on a unit vector indicating the projection direction. One example thereof will be described with reference to the coordinate system shown in FIG.

Here, a unit vector indicating the projection direction (line-of-sight direction) of the projection light beam 22 is assumed to be (X, Y, Z) = (α, β, γ) (α ² + β ² + γ ² = 1). The origin of both coordinate systems is the same point. At this time, the following relational expression (3) is established between the two coordinate systems.
Formula (3)

  The DSC 7 generates the voxel data 21 represented by the coordinate system (X ′, Y ′, Z ′) by performing the coordinate transformation of Expression (3).

  Here, a detailed configuration of the DSC 7 that performs coordinate conversion will be described with reference to FIG. In order to convert from the coordinate system (X, Y, Z) to the coordinate system (X ′, Y ′, Z ′), in addition to the conventional DSC, an X ′ coordinate generator 71a, a Y ′ coordinate generator 71b, and An X′Y′Z ′ coordinate generator 71 composed of a Z ′ coordinate generator 71c is provided. Furthermore, instead of the X coordinate generator 106b and the Y coordinate generator 106c, an XYZ coordinate converter 72 including an X coordinate converter 72a, a Y coordinate converter 72b, and a Z coordinate converter 72c is provided. Further, the coordinate system setting circuit 11 is connected to the XYZ coordinate converter 72.

  First, under the control of the sequencer 76, the X′Y′Z ′ coordinate generator 71 generates position information (X ′, Y ′, Z ′) corresponding to each voxel for generating voxel data (step S02). . The sequencer 76 and the X′Y′Z ′ coordinate generator 71 generate information specifying the voxel and its position, and correspond to the “voxel generator” of the present invention. A signal indicating the position information is sent to the XYZ coordinate converter 72.

  Further, the coordinate system setting circuit 11 sends information indicating the projection direction of the projection light beam 22 arbitrarily set by the operator for line-of-sight setting to the XYZ coordinate converter 72 (step S03). The projective coordinate system setting circuit 11 is connected to the console 10, and when the operator sets the line of sight in an arbitrary direction, signals corresponding to unit vectors (α, β, γ) indicating the line of sight direction are displayed on the console. 10 is output to the coordinate system setting circuit 10, and the coordinate system setting circuit 10 outputs a signal indicating the unit vector to the XYZ coordinate converter 72.

  The setting of the line-of-sight direction by the operator is performed based on an image that has been volume-rendered in the line-of-sight direction set in advance as a default. When the operator sets an arbitrary line-of-sight direction for the default image displayed on the display device 9, unit vectors (α, β, γ) of the line-of-sight direction are converted into XYZ coordinates via the coordinate system setting circuit 10. The data is output to the converter 72, and coordinate conversion processing is performed.

  Then, the XYZ coordinate converter 72 converts the voxel position information (X ′, Y ′, Z ′) sent from the X′Y′Z ′ coordinate generator 71 into a super-vector based on the unit vector indicating the line-of-sight direction. Conversion into position information (X, Y, Z) in an XYZ orthogonal coordinate system fixed to the coordinate system representing the sonic raster data 20 (step S04). This conversion is performed according to the above equation (3).

  Then, the position information converted according to the equation (3) is output to the R address converter 73a, the θ address converter 73b, and the φ address converter 73c, and in the Rθφ coordinate system according to the equation (2), as in the prior art. Is converted into position information (R, θ, φ) (step S05).

  The position information of (R, θ, φ) is output from the Rθφ address converter 73, and the address converter 74 calculates the address information of the recording device 6 for referring to the storage device 6 from the position information (step S06). ). Based on this address information, ultrasonic raster data at coordinates (R, θ, φ) is read from the storage device 6 (step S07). This ultrasonic raster data corresponds to the coordinates (X, Y, Z) after conversion. Then, voxel data is generated by the interpolation processing circuit 75 (step S08).

  In the above description, only one point in the voxel data has been described. However, in order to generate all the voxel data, after generating data for one voxel, the data is created by shifting the coordinates, and all the voxels are generated. Create data.

  Since the ultrasonic raster data is collected discretely, a plurality of ultrasonic raster data is read from the storage device 6, and voxel data is generated by interpolation processing. For the interpolation processing, linear interpolation processing (Tri-Linear interpolation processing) using eight surrounding ultrasonic raster data surrounding the target voxel is used. In this case, the interpolation coefficient is output from the Rθφ address converter 73 to the interpolation processing circuit 75, the interpolation processing is performed using the interpolation coefficient to generate voxel data, and the voxel data is output to the volume rendering processing circuit 8.

  FIG. 5 schematically shows the voxel data 21 after the coordinate conversion. By converting to the X′Y′Z ′ coordinate system, the projection direction of the projection light beam 22 and a predetermined plane of the voxel data 21 can be made orthogonal as shown in FIG. That is, one direction of the voxel data 21 and the projection direction can be made parallel. As a result, as shown in FIG. 5B, the voxel data 21a is arranged on a straight line in the projection direction of the projected light beam 22, so that ray tracing becomes easy. In other words, since the coordinate system of voxel data is fixedly set for the ultrasonic probe in the past, when the projection direction is set obliquely for the voxel data, interpolation processing is necessary in the ray tracing process. In the present embodiment, since they are arranged in a straight line in the projection direction, interpolation processing in volume rendering becomes unnecessary.

  The volume rendering processing circuit 8 receives the coordinate-converted voxel data from the interpolation processing circuit 75, calculates an integral value and a weighted cumulative addition value from each voxel value penetrated by the projection light, and stores the voxel value. Three-dimensional image data in which a plurality of pixels are collected is generated. The display device 9 receives the three-dimensional image data and displays an ultrasonic image displayed in three dimensions on the screen.

  As described above, since the voxel data is arranged in a straight line in the projection direction with one direction of the voxel data parallel to the projection direction, it is not necessary to perform an interpolation process at the time of volume rendering. The spatial resolution is improved compared to Further, since ray tracing becomes easy, it is possible to reduce the load on the CPU when processing by software, and it is possible to simplify the circuit configuration when processing by hardware.

  Further, when voxel data is generated by the scan conversion process by the DSC 7, the voxel data may be generated in the order along the line-of-sight direction. This process will be described with reference to FIG. FIG. 6 is a schematic diagram for explaining the generation order of voxel data.

  As shown in FIG. 6A, first, a voxel data set 21a of a portion through which the projection light beam 22a penetrates is generated. When the generation of the voxel data set 21a on the projection ray 22a is completed, the voxel data set 21b of the portion through which the projection ray 22b passes is then generated. Furthermore, the voxel data set 21c of the part which the projection ray 22c penetrates is produced | generated. In this way, voxel data is sequentially generated along the projected light beam.

  Specifically, in order to obtain voxel data, data is generated for one voxel, and then data with coordinates shifted in the Z ′ direction (projection direction) is generated. Thus, voxel data as shown in FIG. 6A is obtained by generating voxels by shifting in the Z ′ direction. The X′Y′Z ′ coordinate generator 71 generates coordinates including unit vectors (α, β, γ), and then generates coordinates shifted in the Z ′ direction.

  Then, as shown in FIG. 6B, volume rendering is performed in parallel from the portion where the voxel data is generated, and an ultrasonic image expressed in three dimensions is generated. For example, after generating the voxel data set 21a on the projection ray 22a, the volume rendering is performed on the voxel data 21a on the projection ray 22a while the voxel data 21b on the projection ray 22b is being generated. A three-dimensional image is partially generated. Similarly, while generating the voxel data 21c on the projection ray 22c, volume rendering is performed on the voxel data 21b on the projection ray 22b to partially generate a three-dimensional image. Thus, volume rendering can begin before all voxel data is generated.

  Such processing is performed on all the voxel data, and an ultrasonic image expressed in three dimensions is generated. As described above, the scan conversion (SC) process and the volume rendering (VR) process can be simultaneously processed by pipelining. Since parallel processing is possible, delay in image generation can be eliminated and throughput can be improved. As a result, it is possible to generate an ultrasonic image without impairing the real-time property that is an advantage of the ultrasonic diagnostic apparatus.

  Further, in the process of volume rendering, a process called “cropping” may be performed. This “cropping” is a process of visualizing the region of interest by removing unnecessary voxels that exist between the viewpoint and the region of interest (ROI). The region of interest is designated by the console 10. This “cropping” process will be described with reference to FIG. FIG. 7 is a schematic diagram for explaining the cropping process.

  The voxel data 21 is generated only from the region to be visualized without generating the voxel data in the region 25 subjected to the “cropping” process indicated by the broken line in FIG. This process can be executed by changing the voxel data generation start position 26a, as shown in FIG. The generation position of the voxel data is changed by the X′Y′Z ′ coordinate generation circuit 71 under the control of the sequencer 76 that receives the region of interest designation signal from the console 10. By performing this “cropping” process, the voxel data generated by the scan conversion process is reduced, and further, the voxel data for volume rendering is reduced, so that an ultrasonic image can be generated at a higher speed. Become.

  Further, in the state where the projection direction is set obliquely with respect to the voxel data as in the prior art, which part of the voxel data is cropped, that is, the calculation for calculating the generation start position of the voxel data (How to give parameters for calculation) becomes complicated. As a result, when this calculation is performed by hardware, the hardware configuration becomes complicated, and when processing is performed by software, there is a problem that it takes time. According to this embodiment, one direction of the voxel data and the projection direction are parallel (the predetermined plane of the voxel data and the projection direction are orthogonal), and the voxel data is arranged in a straight line in the line-of-sight direction. “Cropping” processing is easier than before, and hardware processing and software processing problems can be solved.

  In the present embodiment, the processing of the DSC 7 is realized by hardware, but may be realized by software using a DSP (Digital Signal Processor) or the like.

[Second Embodiment]
Next, an ultrasonic diagnostic apparatus and an image processing method according to the second embodiment of the present invention will be described with reference to FIGS. The ultrasonic diagnostic apparatus according to the second embodiment generates an image by calculating a maximum value or a minimum value from among the voxel values penetrated by the projection light and storing the obtained values in pixels. Is.

  The configuration of the ultrasonic diagnostic apparatus according to the second embodiment will be described with reference to FIG. FIG. 8 is a functional block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to the second embodiment of the present invention.

  The ultrasonic diagnostic apparatus 30 according to the second embodiment has substantially the same circuit as the ultrasonic diagnostic apparatus 1 according to the first embodiment, but the maximum value / minimum instead of the volume rendering processing circuit 8. A value projection processing device 31 is provided. Similar to the first embodiment, the processes in steps S03 to S08 shown in FIG. 3 are performed. In the second embodiment, after the voxel data is generated in step S08, the maximum / minimum value projection processing device 31 calculates the maximum value or the minimum value from among the voxel values penetrated by the projection rays, A maximum value (minimum value) projection image is generated by storing the obtained maximum value or minimum value in a pixel.

  Even when the maximum value projection process (or the minimum value projection process) is performed from the voxel data to perform the maximum value projection image (or the minimum value projection image), the DSC 7 performs the coordinate conversion as in the first embodiment. Therefore, as shown in FIG. 9, one direction of the voxel data set 32 and the projection direction of the projection light beam 33 are parallel (a predetermined surface of the voxel data set 32 and the projection direction of the projection light beam 33 are orthogonal), Voxel data is arranged in a straight line in the projection direction of the projection light beam 33. This eliminates the need for an interpolation process when performing the ray tracing process, improving the spatial resolution, reducing the CPU load, and simplifying the circuit.

  When the maximum value or minimum value projection processing is performed, the projection direction and voxel range are specified by the console 10, and the coordinate system setting circuit 11 outputs a signal indicating them to the DSC 7, thereby setting the projection direction and the like. . The voxel range (start point and end point of voxel generation) is set by the sequencer 76 in the DSC 7 and the X′Y′Z ′ coordinate generation circuit 71 in the same manner as the “cropping” process. Further, as in the first embodiment, the generation order of voxel data may be generated along the projection direction.

[Third Embodiment]
Next, an ultrasonic diagnostic apparatus and an image processing method according to the third embodiment of the present invention will be described with reference to FIGS. The ultrasonic diagnostic apparatus according to the third embodiment cuts voxel data along a specific plane, generates an MPR image from the cut surface, and further adds a plurality of MPR images orthogonal to the thickness direction to obtain an average. By doing so, an image (referred to as an MPR image with thickness) is generated. FIG. 10 is a functional block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to the third embodiment of the present invention. FIG. 11 is a schematic diagram for explaining processing for generating an MPR image.

  The ultrasonic diagnostic apparatus 40 according to the third embodiment has substantially the same circuit as that of the first embodiment, but includes an MPR generation processing circuit 41 instead of the volume rendering processing circuit 8. Similar to the first embodiment, the processes in steps S03 to S08 shown in FIG. 3 are performed. However, in the third embodiment, processing is performed with the line-of-sight direction as the thickness direction.

  When the DSC 7 performs coordinate conversion in step S04, the DSC 7 performs coordinate conversion so that the thickness direction 44 shown in FIG. 11 and one direction of the voxel data set 42 are parallel to each other. That is, the DSC 7 performs coordinate conversion so that the thickness direction 44 and a predetermined surface of the voxel data set 42 are orthogonal to each other. By this conversion, the direction of the Z ′ axis of the converted coordinates and the thickness direction 44 become parallel. Similar to the conversion process in which the projection direction and one direction of the voxel data set are made parallel in the first embodiment, the DSC 7 makes the thickness direction 44 and one direction of the voxel data set 42 parallel.

  The thickness-added MPR image 45 is generated by adding and averaging a plurality of MPR images orthogonal to the thickness direction 44. When the number of added images is one, the MPR image 45 becomes a normal MPR image.

  When generating an MPR image with thickness generated from a cut surface, it is not necessary to perform the scan conversion process for all regions, and an MPR image can be obtained by generating only voxels within the thickness range. The voxel generation start position and end position are set in the same manner as the “cropping” process. In step S03 shown in FIG. 3, the console 10 designates a thickness that is a range to be added to the thickness direction 44 (designated range 43 shown in FIG. 11), and the coordinate system setting circuit 11 outputs the signals indicated by them to the DSC 7. As a result, the thickness direction 44 and the like are set. The range (start point and end point of voxel generation) is set by the sequencer 76 and the X′Y′Z ′ coordinate generation circuit 71 in the DSC 7, as in the “cropping” process.

  In step S04 and step S05 shown in FIG. 3, the DSC 7 performs coordinate conversion so that the thickness direction 44 and one direction of the voxel data set 42 are parallel to each other. Thus, by converting into the coordinate system in which the thickness direction 44 and one direction of the voxel data set 42 are parallel to each other, the voxel data set 42 can be arranged in a straight line in the thickness direction 44. As in the first embodiment, it is not necessary to perform interpolation processing when generating a thick MPR image. Further, as in the first embodiment, the generation order of voxel data may be generated along the projection direction.

[Fourth Embodiment]
Next, an ultrasonic diagnostic apparatus and image processing method according to the fourth embodiment of the present invention will be described with reference to FIG. The ultrasonic diagnostic apparatus according to the fourth embodiment generates a three-dimensional image using a one-dimensional ultrasonic probe in which piezoelectric elements are divided in a direction perpendicular to the scanning direction. The configuration of the ultrasonic diagnostic apparatus according to the present embodiment is the same as the configuration of the ultrasonic diagnostic apparatus according to the first embodiment, and the configuration of the digital scan converter (DSC) is also the same.

(Operation)
The operation of the ultrasonic diagnostic apparatus according to the fourth embodiment will be described with reference to FIG. FIG. 12 is a diagram for explaining coordinate conversion processing by the ultrasonic diagnostic apparatus according to the fourth embodiment.

Three-dimensional ultrasound raster data is collected by mechanically or manually scanning the one-dimensional ultrasound probe in a direction perpendicular (or substantially perpendicular) to the scan cross section. In FIG. 12, the scanning plane (ultrasonic scanning plane) is the XY plane, and the moving direction of the ultrasonic probe is defined as the Z-axis direction. A plurality of two-dimensional ultrasonic raster data 50 is collected by moving the ultrasonic probe in the Z-axis direction and scanning. A coordinate system of the plurality of two-dimensional ultrasonic raster data is represented by a coordinate system (R, θ, Z) as shown in FIG. The following relational expression (4) is established between the coordinate system (R, θ, Z) of the ultrasonic raster data and the coordinate system (X, Y, Z) of the image data for display.
Formula (4) R = (x ² + y ² ) ^1/2
θ = arctan (x / y)
z = z (constant)
The definitions of distance R and angle θ are shown below.
Distance R: Distance between ultrasonic transmission / reception point (position of one-dimensional ultrasonic probe) and ultrasonic sampling point Angle θ: When the trajectory of the ultrasonic beam is projected on the XY plane, the projected trajectory is Angle to make

  The DSC 7 shown in FIG. 2 generates voxel data from a plurality of two-dimensional ultrasonic raster data 50 shown in FIG. The DSC 7 generates voxel data by performing the processing from step 02 to step S08 shown in FIG. 3 as in the first embodiment. As in the first embodiment, the position information is converted in accordance with Expression (3) in step S04, and the converted position information is converted into the R address converter 73a and the θ address converter 73b shown in FIG. , Φ is output to the address converter 73c.

  The coordinate conversion in step S05 is performed according to the equation (4) and converted into position information (R, θ, z) in the RθZ coordinate system. In this embodiment, the Z component is constant, and the φ address converter 73c shown in FIG. 2 does not perform the conversion process and outputs the Z component as it is.

  Then, the position information of (R, θ, Z) is output from the Rθφ address converter 73, and the address converter 74 calculates address information for referring to the storage device 6 from the position information (step S06). Based on this address information, ultrasonic raster data is read from the storage device 6 (step S07), and voxel data is generated by the interpolation processing circuit 76 (step S08). In this way, voxel data represented by the coordinate system (X ′, Y ′, Z ′) is generated. This voxel data is output to the volume rendering processing circuit 8 to generate a three-dimensional ultrasound image.

  Also in the present embodiment, “cropping” processing, generation of voxel data in order along the line-of-sight direction, maximum / minimum value projection processing, and addition processing in the thickness direction of the MPR image may be performed.

  In this way, even when the three-dimensional ultrasonic raster data is collected by moving the one-dimensional ultrasonic probe, the ray tracing process is facilitated by making the projection direction parallel to one direction of the voxel data. This eliminates the need for interpolation processing in volume rendering or the like.

[Fifth Embodiment]
Next, an ultrasonic diagnostic apparatus and image processing method according to the fifth embodiment of the present invention will be described with reference to FIG. The ultrasonic diagnostic apparatus according to the fifth embodiment generates a three-dimensional image using a one-dimensional ultrasonic probe as in the fourth embodiment. The configuration of the ultrasonic diagnostic apparatus according to the present embodiment is the same as that of the ultrasonic diagnostic apparatus according to the first embodiment, and the configuration of the DSC is also the same.

(Operation)
The operation of the ultrasonic diagnostic apparatus according to the fifth embodiment will be described with reference to FIG. FIG. 13 is a diagram for explaining coordinate conversion processing by the ultrasonic diagnostic apparatus according to the fifth embodiment.

  Three-dimensional ultrasonic raster data is collected by rotating the one-dimensional ultrasonic probe around the living body contact surface of the subject. In FIG. 13, the scanning plane (ultrasonic scanning plane) is the XY plane, and the ultrasonic probe is rotated around the X axis to collect three-dimensional ultrasonic raster data. The rotation angle around the X axis is φ. The ultrasonic raster data obtained in this way is represented in the (R, θ, φ) coordinate system, as shown in FIGS. FIG. 13B is a diagram of the ultrasound raster data viewed from the Z-axis direction, and FIG. 13C is a diagram of the ultrasound raster data viewed from the X-axis direction.

The following relational expression (5) is established between the coordinate system (R, θ, φ) of the ultrasonic raster data and the coordinate system (X, Y, Z) of the image data for display.
Formula (5) R = (x ² + y ² + z ² ) ^1/2
θ = arctan {x / (y ² + z ² ) ^1/2 }
φ = arctan (z / y)
The definitions of distance R and angle θ are shown below.
Distance R: Distance between ultrasonic transmission / reception point (position of one-dimensional ultrasonic probe) and ultrasonic sampling point Angle θ: Angle formed by ultrasonic beam on two-dimensional ultrasonic raster data 60 and Y axis Angle φ: The angle formed by the two-dimensional ultrasonic raster data 60 and the XY plane

  The DSC 7 shown in FIG. 2 generates voxel data from the plurality of two-dimensional ultrasonic raster data 60 shown in FIG. As in the first embodiment, the DSC 7 performs the processing from step S02 to step S08 shown in FIG. 3 to generate voxel data. As in the first embodiment, the position information is converted in accordance with Expression (3) in step S04, and the converted position information is converted into the R address converter 73a and the θ address converter 73b shown in FIG. , Φ is output to the address converter 73c.

  The conversion process in step S05 is performed according to equation (5), and is converted into position information (R, θ, z) in the RθZ coordinate system.

  The position information (R, θ, φ) is output from the Rθφ address converter 73, and the address converter 74 calculates address information for referring to the storage device 6 from the position information (step S06). Based on this address information, ultrasonic raster data is read from the storage device 6 (step S07), and voxel data is generated by the interpolation processing circuit 75 (step S08). In this way, voxel data represented by the coordinate system (X ′, Y ′, Z ′) is generated. This voxel data is output to the volume rendering processing circuit 8 to generate a three-dimensional ultrasound image. Also in this embodiment, a “cropping” process or the like may be performed.

  As described above, even when the three-dimensional ultrasonic raster data is collected by rotating the one-dimensional ultrasonic probe, the ray tracing process becomes easy as in the first embodiment, and volume rendering, etc. No interpolation processing is required.

1 is a functional block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. It is a functional block diagram which shows the detailed structure of the digital scan converter (DSC) with which the ultrasound diagnosing device which concerns on 1st Embodiment is equipped. It is a flowchart for demonstrating operation | movement of the ultrasound diagnosing device which concerns on 1st Embodiment in order. It is a figure for demonstrating the coordinate conversion process by a digital scan converter (DSC). It is a schematic diagram which shows the state which the projection light ray and the voxel data were located in a line. It is a schematic diagram for demonstrating the production | generation order of voxel data. It is a schematic diagram for demonstrating a cropping process. It is a functional block diagram which shows schematic structure of the ultrasonic diagnosing device which concerns on 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the process which produces | generates a maximum value / minimum value projection image. It is a functional block diagram which shows schematic structure of the ultrasonic diagnosing device which concerns on 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the process which produces | generates an MPR image. It is a figure for demonstrating the coordinate transformation process by the ultrasonic diagnosing device which concerns on 4th Embodiment of this invention. It is a figure for demonstrating the coordinate transformation process by the ultrasonic diagnosing device which concerns on 5th Embodiment of this invention. It is a schematic diagram for demonstrating the image generation by volume rendering. It is a schematic diagram for demonstrating the method to produce | generate an MPR image. It is a functional block diagram which shows schematic structure of the ultrasonic diagnosing device which concerns on a prior art. It is a figure for demonstrating the process converted into the two-dimensional image of a rectangular coordinate system. It is a functional block diagram which shows the detailed structure of the digital scan converter (DSC) based on a prior art. It is a figure for demonstrating that voxel data are produced | generated by a scan conversion process. It is a figure for demonstrating the process converted into the three-dimensional image of a rectangular coordinate system. It is a functional block diagram which shows the detailed structure of the digital scan converter (DSC) based on a prior art. It is a schematic diagram for demonstrating the production | generation order of voxel data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 30, 40 Ultrasonic diagnostic apparatus 2 Two-dimensional ultrasonic probe 3 Transmission / reception circuit 4 B mode processing circuit 5 CFM processing circuit 6 Memory | storage device 7 DSC (digital scan converter)
8 Volume rendering processing circuit (VR processing circuit)
DESCRIPTION OF SYMBOLS 9 Display apparatus 10 Console 11 Coordinate system setting circuit 12 Controller 71 X'Y'Z 'coordinate generator 72 XYZ coordinate converter 73 R (theta) phi coordinate converter 74 Address converter 75 Interpolation processing circuit 76 Sequencer

Claims (12)

An ultrasound probe that transmits and receives ultrasound to and from the subject;
Transmitting / receiving means for driving the ultrasonic probe to scan the inside of the subject;
A projection direction setting means for setting a projection position and a projection direction when generating a display image based on a reception signal received by the transmission / reception means;
Voxel data generation means for generating voxel data represented in the coordinate system of the projection direction in order along the projection direction, based on a reception signal obtained by scanning of the transmission / reception means;
Image generating means for generating a display image in the projection direction based on the voxel data;
An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein the voxel data generation unit makes the projection direction parallel to one direction of the voxel data.   The voxel data generation means associates the coordinate system in the projection direction with the collection coordinate system from which the reception signal is received, reads out the reception signal in the collection coordinate system based on the coordinate system in the projection direction, The ultrasonic diagnostic apparatus according to claim 1, wherein the voxel data is generated. It further has an input means for receiving an input operation,
The ultrasonic diagnostic apparatus according to claim 1, wherein the projection direction setting unit sets an arbitrary projection position and projection direction based on the input operation. A region of interest designating unit for designating a region of interest for which an ultrasound image is to be generated;
The ultrasonic diagnostic apparatus according to claim 1, wherein the voxel data generation unit generates voxel data based on a reception signal in the region of interest. Storage means for storing the received signal in association with the collection coordinate system collected by the transmission / reception means;
The voxel data generation means includes
A voxel generator that outputs a coordinate system of the projection direction set based on the projection direction;
A coordinate converter for converting the coordinate system of the projection direction into a three-dimensional orthogonal coordinate system orthogonal to the ultrasonic probe, and converting the converted three-dimensional orthogonal coordinate system into the collection coordinate system;
2. The voxel data associated with the coordinate system of the projection direction is generated by reading the received signal from the storage unit based on the acquired coordinate system converted by the coordinate converter. An ultrasonic diagnostic apparatus according to 1. A first step of performing transmission / reception of an ultrasonic wave to / from a subject with an ultrasonic probe and setting a projection position and a projection direction when generating a display image based on the received signal;
A second step of generating, in the order along the projection direction, xel data represented by the coordinate system of the projection direction based on the received signal obtained in the first step;
A third step of generating a display image based on the voxel data;
An image processing method comprising: The image processing method according to claim 7 , wherein in the second step, the projection direction and one direction of the voxel data are made parallel to each other. In the second step, the coordinate system of the projection direction is associated with the acquisition coordinate system from which the reception signal is received, and the reception signal in the acquisition coordinate system is read based on the coordinate system of the projection direction, the image processing method according to claim 7 or claim 8, characterized in that generating the voxel data. In the first step, receives an input operation, an image processing method according to any one of claims 7 to 9, characterized in that to set the arbitrary projection position and projection direction based on the input operation . A fourth step of specifying a region of interest that specifies a region of interest in which ultrasound is to be generated;
In the second step, the image processing method according to any one of claims 7 to 10, characterized in that to generate the voxel data based on the received signal in the ROI. A fifth step of storing the received signal in a storage device in association with the collection coordinate system collected by the transmission / reception means;
The second step includes
A sixth step of outputting a coordinate system of the projection direction set based on the projection direction;
Converting the coordinate system in the projection direction into a three-dimensional orthogonal coordinate system orthogonal to the ultrasonic probe, and converting the converted three-dimensional orthogonal coordinate system into the collection coordinate system. ,
The voxel data associated with the coordinate system in the projection direction is generated by reading out the received signal from the storage device based on the acquired coordinate system converted in the seventh step. 8. The image processing method according to 7 .

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