JP5813986B2 - Image processing system, apparatus, method and program - Google Patents

Description

  Embodiments described herein relate generally to an image processing system, apparatus, method, and program.

  Conventionally, a monitor capable of stereoscopically viewing a two-parallax image taken from two viewpoints using a dedicated device such as stereoscopic glasses has been put into practical use. In recent years, monitors that can stereoscopically view multi-parallax images (for example, 9 parallax images) taken from a plurality of viewpoints using a light beam controller such as a lenticular lens have been put into practical use. Note that a 2-parallax image or a 9-parallax image displayed on a stereoscopically viewable monitor may be generated by estimating the depth information of an image taken from one viewpoint and performing image processing using the estimated information. .

  On the other hand, a medical image diagnostic apparatus such as an X-ray CT (Computed Tomography) apparatus, an MRI (Magnetic Resonance Imaging) apparatus, or an ultrasonic diagnostic apparatus is practically capable of generating three-dimensional medical image data (hereinafter referred to as volume data). It has become. From the volume data generated by the medical image diagnostic apparatus, a volume rendering image (parallax image) having an arbitrary number of parallaxes can be generated at an arbitrary parallax angle. In view of this, it has been studied to display a two-dimensional volume rendering image generated from volume data in a stereoscopic manner on a stereoscopically visible monitor that has recently been put into practical use.

  However, for example, when a process for generating a nine-parallax image from volume data is executed in real time according to an observer's operation (volume data rotation or enlargement / reduction, panorama display, clipping, etc.), the amount of computation of the volume rendering process is reduced. Because of this, it has been difficult to display interactive processing results to the observer.

JP 2005-84414 A

  The problem to be solved by the present invention is to provide an image processing system, apparatus, method, and program capable of generating an image for stereoscopic viewing according to the request of the observer in a time that does not give stress to the observer. That is.

The image processing system according to the embodiment includes a rendering processing unit and a control unit. The rendering processing unit generates a parallax image group, which is a parallax image having a predetermined number of parallaxes displayed on the stereoscopic display device, from a volume data that is three-dimensional medical image data by a rendering process. The control unit performs the rendering process so as to change an image generation parameter related to a data amount of the parallax image group according to a change frequency per unit time of a rendering condition changing operation by an operator who refers to the stereoscopic display device. Control part.

FIG. 1 is a diagram for explaining a configuration example of an image processing system according to the first embodiment. FIG. 2 is a diagram for explaining an example of a stereoscopic display monitor that performs stereoscopic display using two parallax images. FIG. 3 is a diagram for explaining an example of a stereoscopic display monitor that performs stereoscopic display using nine parallax images. FIG. 4 is a diagram for explaining a configuration example of the workstation according to the first embodiment. FIG. 5 is a diagram for explaining a configuration example of the rendering processing unit shown in FIG. FIG. 6 is a diagram for explaining an example of volume rendering processing according to the first embodiment. FIG. 7 is a diagram for explaining a configuration example of the terminal device according to the first embodiment. FIG. 8 is a diagram for explaining an example of a rendering condition change request. FIG. 9 is a diagram (1) for explaining an example of the rendering control process of the control unit according to the first embodiment. FIG. 10 is a diagram (2) for explaining an example of the rendering control process of the control unit according to the first embodiment. FIG. 11 is a flowchart for explaining the rendering control processing of the workstation according to the first embodiment. FIG. 12 is a diagram (1) for explaining an example of the rendering control process of the control unit according to the second embodiment. FIG. 13 is a diagram (2) for explaining an example of the rendering control process of the control unit according to the second embodiment. FIG. 14A is a diagram (3) for explaining an example of the rendering control process of the control unit according to the second embodiment. FIG. 14-2 is a diagram (4) illustrating an example of the rendering control process of the control unit according to the second embodiment. FIG. 15 is a flowchart for explaining the rendering control process of the workstation according to the second embodiment. FIG. 16 is a diagram for explaining a modification of the first embodiment and the second embodiment.

  Hereinafter, embodiments of an image processing system and an image processing apparatus will be described in detail with reference to the accompanying drawings. In the following, an image processing system including a workstation having a function as an image processing apparatus will be described as an embodiment. Here, the terms used in the following embodiments will be described. The “parallax image group” is an image generated by performing volume rendering processing by moving the viewpoint position by a predetermined parallax angle with respect to volume data. It is a group. That is, the “parallax image group” includes a plurality of “parallax images” having different “viewpoint positions”. The “parallax angle” is an adjacent viewpoint position among the viewpoint positions set for generating the “parallax image group” and a predetermined position in the space represented by the volume data (for example, the center of the space). ). The “parallax number” is the number of “parallax images” necessary for stereoscopic viewing on the stereoscopic display monitor. The “9 parallax images” described below is a “parallax image group” composed of nine “parallax images”. The “two-parallax image” described below is a “parallax image group” composed of two “parallax images”.

(First embodiment)
First, a configuration example of the image processing system according to the first embodiment will be described. FIG. 1 is a diagram for explaining a configuration example of an image processing system according to the first embodiment.

  As shown in FIG. 1, the image processing system 1 according to the first embodiment includes a medical image diagnostic apparatus 110, an image storage apparatus 120, a workstation 130, and a terminal apparatus 140. Each apparatus illustrated in FIG. 1 is in a state where it can communicate with each other directly or indirectly by, for example, an in-hospital LAN (Local Area Network) 2 installed in a hospital. For example, when a PACS (Picture Archiving and Communication System) is introduced into the image processing system 1, each apparatus transmits and receives medical images and the like according to DICOM (Digital Imaging and Communications in Medicine) standards.

  The image processing system 1 generates a parallax image group from volume data that is three-dimensional medical image data generated by the medical image diagnostic apparatus 110, and displays the parallax image group on a stereoscopically viewable monitor. Provide medical images that can be viewed stereoscopically to doctors and laboratory technicians working in hospitals. Specifically, in the first embodiment, the workstation 130 performs various image processing on the volume data to generate a parallax image group. In addition, the workstation 130 and the terminal device 140 have a monitor that can be viewed stereoscopically, and displays a parallax image group generated by the workstation 130 on the monitor. Further, the image storage device 120 stores the volume data generated by the medical image diagnostic device 110 and the parallax image group generated by the workstation 130. That is, the workstation 130 and the terminal device 140 acquire volume data and a parallax image group from the image storage device 120, process them, and display them on a monitor. Hereinafter, each device will be described in order.

  The medical image diagnostic apparatus 110 includes an X-ray diagnostic apparatus, an X-ray CT (Computed Tomography) apparatus, an MRI (Magnetic Resonance Imaging) apparatus, an ultrasonic diagnostic apparatus, a SPECT (Single Photon Emission Computed Tomography) apparatus, and a PET (Positron Emission computed Tomography). ) Apparatus, a SPECT-CT apparatus in which a SPECT apparatus and an X-ray CT apparatus are integrated, a PET-CT apparatus in which a PET apparatus and an X-ray CT apparatus are integrated, or a group of these apparatuses. Further, the medical image diagnostic apparatus 110 according to the first embodiment can generate three-dimensional medical image data (volume data).

  Specifically, the medical image diagnostic apparatus 110 according to the first embodiment generates volume data by imaging a subject. For example, the medical image diagnostic apparatus 110 collects data such as projection data and MR signals by imaging the subject, and medical image data of a plurality of axial surfaces along the body axis direction of the subject from the collected data. By reconfiguring, volume data is generated. For example, the medical image diagnostic apparatus 110 reconstructs 500 pieces of medical image data on the axial plane. The 500 axial medical image data groups are volume data.

  Further, the medical image diagnostic apparatus 110 according to the first embodiment transmits the generated volume data to the image storage apparatus 120. The medical image diagnostic apparatus 110 identifies, for example, a patient ID for identifying a patient, an examination ID for identifying an examination, and the medical image diagnostic apparatus 110 as supplementary information when transmitting volume data to the image storage apparatus 120. A device ID, a series ID for identifying one shot by the medical image diagnostic device 110, and the like are transmitted.

  The image storage device 120 is a database that stores medical images. Specifically, the image storage device 120 according to the first embodiment stores the volume data transmitted from the medical image diagnostic device 110 in a storage unit and stores it. Further, the image storage device 120 according to the first embodiment can store a parallax image group generated from the volume data by the workstation 130 in a storage unit and store the parallax image group. In such a case, the workstation 130 transmits the generated parallax image group to the image storage device 120, and the image storage device 120 stores the parallax image group transmitted from the workstation 130 in the storage unit and stores it. In the present embodiment, the workstation 130 illustrated in FIG. 1 and the image storage device 120 may be integrated by using the workstation 130 that can store a large-capacity image. That is, this embodiment may be a case where volume data or a parallax image group is stored in the workstation 130 itself.

  In the first embodiment, the volume data and the parallax image group stored in the image storage device 120 are stored in association with the patient ID, examination ID, device ID, series ID, and the like. Therefore, the workstation 130 and the terminal device 140 acquire necessary volume data and a parallax image group from the image storage device 120 by performing a search using a patient ID, an examination ID, a device ID, a series ID, and the like.

  The workstation 130 is an image processing apparatus that performs image processing on medical images. Specifically, the workstation 130 according to the first embodiment performs various rendering processes on the volume data acquired from the image storage device 120 to generate a parallax image group. A parallax image group is a plurality of parallax images taken from a plurality of viewpoints. For example, a parallax image group displayed on a monitor capable of stereoscopically viewing nine parallax images with the naked eye has a viewpoint position. It is nine different parallax images.

  In addition, the workstation 130 according to the first embodiment includes a stereoscopically visible monitor (hereinafter, stereoscopic display monitor) as a display unit. The workstation 130 generates a parallax image group and displays the generated parallax image group on the stereoscopic display monitor. As a result, the operator of the workstation 130 can perform an operation for generating a parallax image group while confirming a stereoscopically visible medical image displayed on the stereoscopic display monitor.

  Further, the workstation 130 transmits the generated parallax image group to the image storage device 120. In addition, when transmitting the parallax image group to the image storage device 120, the workstation 130 transmits, for example, a patient ID, an examination ID, a device ID, a series ID, and the like as incidental information. Further, the incidental information transmitted when transmitting the parallax image group to the image storage device 120 includes incidental information regarding the parallax image group. The incidental information regarding the parallax image group includes the number of parallax images (for example, “9”), the resolution of the parallax images (for example, “466 pixels × 350 pixels”), and the like. In addition, the workstation 130 can also transmit the generated parallax image group to the terminal device 140 in response to a stereoscopic view request from the terminal device 140.

  Here, the workstation 130 according to the first embodiment generates a parallax image group in real time according to an operator's request. For example, the workstation 130 according to the first embodiment generates a parallax image group in response to a request from the operator of the own apparatus. Alternatively, the workstation 130 according to the first embodiment generates a parallax image group in response to a request from an operator of the terminal device 140 described below, and transmits the generated parallax image group to the terminal device 140.

  The terminal device 140 is a device that allows a doctor or laboratory technician working in a hospital to view a medical image. For example, the terminal device 140 is a PC (Personal Computer), a tablet PC, a PDA (Personal Digital Assistant), a mobile phone, or the like operated by a doctor or laboratory technician working in a hospital. Specifically, the terminal device 140 according to the first embodiment includes a stereoscopic display monitor as a display unit. Further, the terminal device 140 acquires a parallax image group from the workstation 130 or the image storage device 120, and displays the acquired parallax image group on the stereoscopic display monitor. As a result, a doctor or laboratory technician who is an observer can view a medical image that can be viewed stereoscopically.

  Here, the stereoscopic display monitor included in the workstation 130 and the terminal device 140 will be described. A general-purpose monitor that is most popular at present displays a two-dimensional image in two dimensions, and cannot display a two-dimensional image in three dimensions. If an observer requests stereoscopic viewing on a general-purpose monitor, an apparatus that outputs an image to the general-purpose monitor needs to display two parallax images that can be viewed stereoscopically by the observer in parallel by the parallel method or the intersection method. is there. Alternatively, an apparatus that outputs an image to a general-purpose monitor, for example, uses an after-color method with an eyeglass that has a red cellophane attached to the left eye portion and a blue cellophane attached to the right eye portion. It is necessary to display a stereoscopically viewable image.

  On the other hand, as a stereoscopic display monitor, there is a stereoscopic display monitor that enables a stereoscopic view of a two-parallax image (also referred to as a binocular parallax image) by using dedicated equipment such as stereoscopic glasses.

  FIG. 2 is a diagram for explaining an example of a stereoscopic display monitor that performs stereoscopic display using two parallax images. An example shown in FIG. 2 is a stereoscopic display monitor that performs stereoscopic display by a shutter method, and shutter glasses are used as stereoscopic glasses worn by an observer who observes the monitor. Such a stereoscopic display monitor emits two parallax images alternately on the monitor. For example, the monitor shown in FIG. 2A alternately emits a left-eye image and a right-eye image at 120 Hz. Here, as shown in FIG. 2A, the monitor is provided with an infrared emitting unit, and the infrared emitting unit controls the emission of infrared rays in accordance with the timing at which the image is switched.

  Moreover, the infrared rays emitted from the infrared ray emitting portion are received by the infrared ray receiving portion of the shutter glasses shown in FIG. A shutter is attached to each of the left and right frames of the shutter glasses, and the shutter glasses alternately switch the transmission state and the light shielding state of the left and right shutters according to the timing when the infrared light receiving unit receives the infrared rays. Hereinafter, the switching process between the transmission state and the light shielding state in the shutter will be described.

  As shown in FIG. 2B, each shutter has an incident-side polarizing plate and an output-side polarizing plate, and a liquid crystal layer between the incident-side polarizing plate and the output-side polarizing plate. Have Further, as shown in FIG. 2B, the incident-side polarizing plate and the outgoing-side polarizing plate are orthogonal to each other. Here, as shown in FIG. 2B, in the “OFF” state where no voltage is applied, the light that has passed through the polarizing plate on the incident side is rotated by 90 ° by the action of the liquid crystal layer, and is emitted on the outgoing side. Is transmitted through the polarizing plate. That is, a shutter to which no voltage is applied is in a transmissive state.

  On the other hand, as shown in FIG. 2B, in the “ON” state where a voltage is applied, the polarization rotation action caused by the liquid crystal molecules in the liquid crystal layer disappears. It will be blocked by the polarizing plate on the exit side. That is, the shutter to which the voltage is applied is in a light shielding state.

  Therefore, for example, the infrared emitting unit emits infrared rays during a period in which an image for the left eye is displayed on the monitor. The infrared light receiving unit applies a voltage to the right-eye shutter without applying a voltage to the left-eye shutter during a period of receiving the infrared light. Accordingly, as shown in FIG. 2A, the right-eye shutter is in a light-shielding state and the left-eye shutter is in a transmissive state, so that an image for the left eye is incident on the left eye of the observer. On the other hand, the infrared ray emitting unit stops emitting infrared rays while the right-eye image is displayed on the monitor. The infrared light receiving unit applies a voltage to the left-eye shutter without applying a voltage to the right-eye shutter during a period in which no infrared light is received. Accordingly, the left-eye shutter is in a light-shielding state and the right-eye shutter is in a transmissive state, so that an image for the right eye enters the right eye of the observer. As described above, the stereoscopic display monitor illustrated in FIG. 2 displays an image that can be viewed stereoscopically by the observer by switching the image displayed on the monitor and the state of the shutter in conjunction with each other. As a stereoscopic display monitor capable of stereoscopically viewing a two-parallax image, a monitor adopting a polarized glasses method is also known in addition to the shutter method described above.

  Furthermore, as a stereoscopic display monitor that has been put into practical use in recent years, there is a stereoscopic display monitor that allows a viewer to stereoscopically view a multi-parallax image such as a 9-parallax image with the naked eye by using a light controller such as a lenticular lens. . Such a stereoscopic display monitor enables stereoscopic viewing based on binocular parallax, and also enables stereoscopic viewing based on motion parallax that also changes the image observed in accordance with the viewpoint movement of the observer.

  FIG. 3 is a diagram for explaining an example of a stereoscopic display monitor that performs stereoscopic display using nine parallax images. In the stereoscopic display monitor shown in FIG. 3, a light beam controller is arranged on the front surface of a flat display surface 200 such as a liquid crystal panel. For example, in the stereoscopic display monitor shown in FIG. 3, a vertical lenticular sheet 201 whose optical aperture extends in the vertical direction is attached to the front surface of the display surface 200 as a light beam controller. In the example shown in FIG. 3, the vertical lenticular sheet 201 is pasted so that the convex portion of the vertical lenticular sheet 201 becomes the front surface, but the convex portion of the vertical lenticular sheet 201 is pasted so as to face the display surface 200. There may be.

  As shown in FIG. 3, the display surface 200 has an aspect ratio of 3: 1 and pixels in which three sub-pixels, red (R), green (G), and blue (B), are arranged in the vertical direction. 202 are arranged in a matrix. The stereoscopic display monitor shown in FIG. 3 converts a nine-parallax image composed of nine images into an intermediate image arranged in a predetermined format (for example, a lattice shape), and then outputs it to the display surface 200. For example, a nine-parallax image is converted into an intermediate image in a grid-like format in which nine images are arranged in “3 rows and 3 columns” and output to the display surface 200. That is, the stereoscopic display monitor shown in FIG. 3 assigns and outputs nine pixels at the same position in nine parallax images to nine columns of pixels 202. The nine columns of pixels 202 constitute a unit pixel group 203 that simultaneously displays nine images with different viewpoint positions.

  The nine parallax images simultaneously output as the unit pixel group 203 on the display surface 200 are emitted as parallel light by, for example, an LED (Light Emitting Diode) backlight, and further emitted in multiple directions by the vertical lenticular sheet 201. As the light of each pixel of the nine-parallax image is emitted in multiple directions, the light incident on the right eye and the left eye of the observer changes in conjunction with the position of the observer (viewpoint position). That is, the parallax angle between the parallax image incident on the right eye and the parallax image incident on the left eye differs depending on the viewing angle of the observer. Thereby, the observer can visually recognize the photographing object in three dimensions at each of the nine positions shown in FIG. 3, for example. In addition, for example, the observer can view the image three-dimensionally in a state of facing the object to be imaged at the position “5” shown in FIG. 3, and at each position other than “5” shown in FIG. It can be visually recognized in a three-dimensional manner with the direction of the object changed. Note that the stereoscopic display monitor shown in FIG. 3 is merely an example. As shown in FIG. 3, the stereoscopic display monitor that displays a nine-parallax image may be a horizontal stripe liquid crystal of “RRR..., GGG..., BBB. .. ”” May be used. The stereoscopic display monitor shown in FIG. 3 may be a vertical lens system in which the lenticular sheet is vertical as shown in FIG. 3 or a diagonal lens system in which the lenticular sheet is diagonal. There may be. Further, the format of the intermediate image is not limited to the “3 rows × 3 columns” grid. For example, the format of the intermediate image may be an arbitrary format according to the monitor specification, such as “1 row 9 column” or “9 row 1 column”.

  Hereinafter, the stereoscopic display monitor described with reference to FIG. 2 is referred to as a two-parallax monitor. Hereinafter, the stereoscopic display monitor described with reference to FIG. 3 is referred to as a 9-parallax monitor. That is, the two-parallax monitor is a stereoscopic display device that enables stereoscopic viewing with binocular parallax. In addition, the 9-parallax monitor enables stereoscopic viewing by binocular parallax, and further displays the 9 images (9-parallax images) at the same time so that the observer can respond according to the “observer's viewpoint movement (motion parallax)”. This is a stereoscopic display device capable of changing an image to be observed.

  So far, the configuration example of the image processing system 1 according to the first embodiment has been briefly described. Note that the application of the image processing system 1 described above is not limited when PACS is introduced. For example, the image processing system 1 is similarly applied when an electronic medical chart system that manages an electronic medical chart to which a medical image is attached is introduced. In this case, the image storage device 120 is a database that stores electronic medical records. Further, for example, the image processing system 1 is similarly applied when a HIS (Hospital Information System) and a RIS (Radiology Information System) are introduced. The image processing system 1 is not limited to the configuration example described above. The functions and sharing of each device may be appropriately changed according to the operation mode.

  Next, a configuration example of the workstation according to the first embodiment will be described with reference to FIG. FIG. 4 is a diagram for explaining a configuration example of the workstation according to the first embodiment. In the following, the “parallax image group” is a group of stereoscopic images (volume rendering image group) generated by performing volume rendering processing on volume data. Further, the “parallax image” is an individual image constituting the “parallax image group”. That is, the “parallax image group” includes a plurality of “parallax images” having different viewpoint positions.

  The workstation 130 according to the first embodiment is a high-performance computer suitable for image processing and the like, and as illustrated in FIG. 4, an input unit 131, a display unit 132, a communication unit 133, and a storage unit 134. And a control unit 135 and a rendering processing unit 136. In the following, a case where the workstation 130 is a high-performance computer suitable for image processing or the like will be described. However, the present invention is not limited to this, and may be any information processing apparatus. For example, any personal computer may be used.

  The input unit 131 is a mouse, a keyboard, a trackball, or the like, and receives input of various operations on the workstation 130 from an operator. Specifically, the input unit 131 according to the first embodiment receives input of information for acquiring volume data to be subjected to rendering processing from the image storage device 120. For example, the input unit 131 receives input of a patient ID, an examination ID, a device ID, a series ID, and the like. Further, the input unit 131 according to the first embodiment receives an input of a condition (rendering condition) related to rendering processing.

  The display unit 132 is a liquid crystal panel or the like as a stereoscopic display monitor, and displays various information. Specifically, the display unit 132 according to the first embodiment displays a GUI (Graphical User Interface) for receiving various operations from the operator, a parallax image group, and the like. For example, the display unit 132 is a 2-parallax monitor or a 9-parallax monitor. Below, the case where the display part 132 is a 9 parallax monitor is demonstrated. The communication unit 133 is a NIC (Network Interface Card) or the like, and performs communication with other devices.

  The storage unit 134 is a hard disk, a semiconductor memory element, or the like, and stores various types of information. Specifically, the storage unit 134 according to the first embodiment stores volume data acquired from the image storage device 120 via the communication unit 133. In addition, the storage unit 134 according to the first embodiment stores volume data during rendering processing, a group of parallax images generated by the rendering processing, and the like.

  The control unit 135 is an electronic circuit such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), and the entire workstation 130. Take control.

  For example, the control unit 135 according to the first embodiment controls the display of the GUI and the display of the parallax image group on the display unit 132. For example, the control unit 135 controls transmission / reception of volume data and a parallax image group performed with the image storage device 120 via the communication unit 133. For example, the control unit 135 controls the rendering process performed by the rendering processing unit 136. For example, the control unit 135 controls reading of volume data from the storage unit 134 and storage of the parallax image group in the storage unit 134.

  The rendering processing unit 136 performs various rendering processes on the volume data acquired from the image storage device 120 under the control of the control unit 135 to generate a parallax image group. Specifically, the rendering processing unit 136 according to the first embodiment reads volume data from the storage unit 134 and first performs preprocessing on the volume data. Next, the rendering processing unit 136 performs volume rendering processing on the pre-processed volume data to generate a parallax image group. Subsequently, the rendering processing unit 136 generates a two-dimensional image in which various kinds of information (scale, patient name, examination item, etc.) are drawn, and superimposes it on each of the parallax image groups, thereby outputting 2 for output. Generate a dimensional image. Then, the rendering processing unit 136 stores the generated parallax image group and the output two-dimensional image in the storage unit 134. In the first embodiment, the rendering process is the entire image process performed on the volume data. The volume rendering process is a two-dimensional image reflecting three-dimensional information in the rendering process. It is a process to generate. For example, a parallax image corresponds to the medical image generated by the rendering process.

  FIG. 5 is a diagram for explaining a configuration example of the rendering processing unit shown in FIG. As illustrated in FIG. 5, the rendering processing unit 136 includes a preprocessing unit 1361, a 3D image processing unit 1362, and a 2D image processing unit 1363. The preprocessing unit 1361 performs preprocessing on the volume data, the 3D image processing unit 1362 generates a parallax image group from the preprocessed volume data, and the 2D image processing unit 1363 stores various information on the parallax image group. A two-dimensional image for output on which is superimposed is generated. Hereinafter, each part is demonstrated in order.

  The preprocessing unit 1361 is a processing unit that performs various types of preprocessing when rendering processing is performed on volume data, and includes an image correction processing unit 1361a, a three-dimensional object fusion unit 1361e, and a three-dimensional object display area setting. Part 1361f.

  The image correction processing unit 1361a is a processing unit that performs image correction processing when processing two types of volume data as one volume data, and as shown in FIG. 5, a distortion correction processing unit 1361b, a body motion correction processing unit, 1361c and an inter-image registration processing unit 1361d. For example, the image correction processing unit 1361a performs image correction processing when processing volume data of a PET image generated by a PET-CT apparatus and volume data of an X-ray CT image as one volume data. Alternatively, the image correction processing unit 1361a performs image correction processing when processing the volume data of the T1-weighted image and the volume data of the T2-weighted image generated by the MRI apparatus as one volume data.

  In addition, the distortion correction processing unit 1361b corrects the data distortion caused by the collection conditions at the time of data collection by the medical image diagnostic apparatus 110 in each volume data. Further, the body motion correction processing unit 1361c corrects the movement caused by the body motion of the subject at the time of collecting the data used for generating the individual volume data. Further, the inter-image registration processing unit 1361d performs registration (Registration) using, for example, a cross-correlation method between the two volume data subjected to the correction processing by the distortion correction processing unit 1361b and the body motion correction processing unit 1361c. ).

  The three-dimensional object fusion unit 1363e fuses a plurality of volume data that has been aligned by the inter-image registration processing unit 1361d. Note that the processing of the image correction processing unit 1361a and the three-dimensional object fusion unit 1361e is omitted when rendering processing is performed on single volume data.

  The three-dimensional object display region setting unit 1361f is a processing unit that sets a display region corresponding to the display target organ designated by the operator, and includes a segmentation processing unit 1361g. The segmentation processing unit 1361g is a processing unit that extracts organs such as the heart, lungs, and blood vessels designated by the operator by, for example, a region expansion method based on pixel values (voxel values) of volume data.

  Note that the segmentation processing unit 1361g does not perform the segmentation process when the display target organ is not designated by the operator. The segmentation processing unit 1361g extracts a plurality of corresponding organs when a plurality of display target organs are designated by the operator. Further, the processing of the segmentation processing unit 1361g may be executed again in response to an operator fine adjustment request referring to the rendered image.

  The 3D image processing unit 1362 performs volume rendering processing on the pre-processed volume data processed by the preprocessing unit 1361. As a processing unit that performs volume rendering processing, a three-dimensional image processing unit 1362 includes a projection method setting unit 1362a, a three-dimensional geometric transformation processing unit 1362b, a three-dimensional object appearance processing unit 1362f, and a three-dimensional virtual space rendering unit 1362k. Have

  The projection method setting unit 1362a determines a projection method for generating a parallax image group. For example, the projection method setting unit 1362a determines whether to execute the volume rendering process by the parallel projection method or the perspective projection method.

  The three-dimensional geometric transformation processing unit 1362b is a processing unit that determines information for transforming volume data on which volume rendering processing is performed into a three-dimensional geometrical structure. The three-dimensional geometric transformation processing unit 1362b includes a parallel movement processing unit 1362c, a rotation processing unit 1362d, and an enlargement unit. A reduction processing unit 1362e is included. The parallel movement processing unit 1362c is a processing unit that determines the amount of movement to translate the volume data when the viewpoint position when performing the volume rendering processing is translated, and the rotation processing unit 1362d performs the volume rendering processing. This is a processing unit that determines the amount of movement by which the volume data is rotationally moved when the viewpoint position during the rotation is rotationally moved. The enlargement / reduction processing unit 1362e is a processing unit that determines the enlargement rate or reduction rate of the volume data when enlargement or reduction of the parallax image group is requested.

  The three-dimensional object appearance processing unit 1362f includes a three-dimensional object color processing unit 1362g, a three-dimensional object opacity processing unit 1362h, a three-dimensional object material processing unit 1362i, and a three-dimensional virtual space light source processing unit 1362j. The three-dimensional object appearance processing unit 1362f performs a process of determining the display state of the displayed parallax image group in response to an operator's request, for example.

  The three-dimensional object color processing unit 1362g is a processing unit that determines a color to be colored for each region segmented by the volume data. The three-dimensional object opacity processing unit 1362h is a processing unit that determines the opacity (Opacity) of each voxel constituting each region segmented by volume data. It should be noted that the area behind the area having the opacity of “100%” in the volume data is not drawn in the parallax image group. In addition, an area in which the opacity is “0%” in the volume data is not drawn in the parallax image group.

  The three-dimensional object material processing unit 1362i is a processing unit that determines the material of each region segmented by volume data and adjusts the texture when the region is rendered. The three-dimensional virtual space light source processing unit 1362j is a processing unit that determines the position of the virtual light source installed in the three-dimensional virtual space and the type of the virtual light source when performing volume rendering processing on the volume data. Examples of the virtual light source include a light source that emits parallel light rays from infinity and a light source that emits radial light rays from the viewpoint.

  The three-dimensional virtual space rendering unit 1362k performs volume rendering processing on the volume data to generate a parallax image group. The three-dimensional virtual space rendering unit 1362k performs various types of information determined by the projection method setting unit 1362a, the three-dimensional geometric transformation processing unit 1362b, and the three-dimensional object appearance processing unit 1362f as necessary when performing the volume rendering process. Is used.

  Here, the volume rendering process by the three-dimensional virtual space rendering unit 1362k is performed according to the rendering conditions. For example, the rendering condition is “parallel projection method” or “perspective projection method”. For example, the rendering condition is “reference viewpoint position and parallax angle”. Further, for example, the rendering conditions are “translation of viewpoint position”, “rotational movement of viewpoint position”, “enlargement of parallax image group”, and “reduction of parallax image group”. Further, for example, the rendering conditions are “color to be colored”, “transparency”, “texture”, “position of virtual light source”, and “type of virtual light source”. Such a rendering condition may be accepted from the operator via the input unit 131 or may be initially set. In any case, the three-dimensional virtual space rendering unit 1362k receives a rendering condition from the control unit 135, and performs volume rendering processing on the volume data according to the rendering condition. At this time, the projection method setting unit 1362a, the three-dimensional geometric transformation processing unit 1362b, and the three-dimensional object appearance processing unit 1362f determine various pieces of necessary information according to the rendering conditions, so the three-dimensional virtual space rendering unit 1362k. Generates a parallax image group using the determined various pieces of information.

  FIG. 6 is a diagram for explaining an example of volume rendering processing according to the first embodiment. For example, as shown in FIG. 6A, the three-dimensional virtual space rendering unit 1362k accepts the parallel projection method as a rendering condition, and further sets the reference viewpoint position (5) and the parallax angle “1 degree”. Suppose you accept. In such a case, the three-dimensional virtual space rendering unit 1362k sets a light source that emits parallel light rays from infinity along the line-of-sight direction, as shown in FIG. Then, the three-dimensional virtual space rendering unit 1362k translates the position of the viewpoint from (1) to (9) so that the parallax angle is every “1 degree”, and the parallax angle (gaze direction) by the parallel projection method. Nine parallax images with different angles are generated by 1 degree.

  Alternatively, as shown in FIG. 6B, the three-dimensional virtual space rendering unit 1362k accepts a perspective projection method as a rendering condition, and further sets the reference viewpoint position (5) and the parallax angle “1 degree”. Suppose you accept. In such a case, as shown in FIG. 6B, the three-dimensional virtual space rendering unit 1362k sets a point light source and a surface light source that irradiates light three-dimensionally radially around the line-of-sight direction at each viewpoint. . For example, the three-dimensional virtual space rendering unit 1362k sets the position of the viewpoint (1) to (9) so that the parallax angle is every “one degree” around the center (center of gravity) of the cut surface of the volume data. Nine parallax images having different parallax angles by 1 degree are generated by the perspective projection method. When performing the perspective projection method, the viewpoints (1) to (9) may be translated depending on the rendering conditions. As shown in FIGS. 6A and 6B, the line-of-sight direction is a direction from the viewpoint toward the center (center of gravity) of the cut surface of the volume data.

  Alternatively, as shown in FIG. 6C, the three-dimensional virtual space rendering unit 1362k radiates light in a two-dimensional manner centering on the line-of-sight direction with respect to the vertical direction of the displayed volume rendering image. For the horizontal direction of the volume rendering image to be displayed, a volume rendering process that uses both the parallel projection method and the perspective projection method by setting a light source that emits parallel light rays from infinity along the viewing direction. May be performed.

  The nine parallax images generated in this way are a parallax image group. In the first embodiment, the nine parallax images are converted into intermediate images arranged in a predetermined format (for example, a lattice shape) by the control unit 135, for example, and are output to the display unit 132 as a stereoscopic display monitor. Then, the operator of the workstation 130 can perform an operation for generating a parallax image group while confirming a stereoscopically viewable medical image displayed on the stereoscopic display monitor.

  In the example of FIG. 6, the case where the projection method, the reference viewpoint position, and the parallax angle are received as the rendering conditions has been described. However, the three-dimensional virtual space is similarly applied when other conditions are received as the rendering conditions. The rendering unit 1362k generates a parallax image group while reflecting each rendering condition.

  The three-dimensional virtual space rendering unit 1362k has a function of reconstructing an MPR image from volume data by performing not only volume rendering but also a cross-section reconstruction method (MPR: Multi Planer Reconstruction). The three-dimensional virtual space rendering unit 1362k also has a function of performing “Curved MPR” and a function of performing “Intensity Projection”.

  Subsequently, the parallax image group generated from the volume data by the three-dimensional image processing unit 1362 is set as an underlay. Then, an overlay (Overlay) on which various types of information (scale, patient name, examination item, etc.) are drawn is superimposed on the underlay, thereby obtaining a two-dimensional image for output. The two-dimensional image processing unit 1363 is a processing unit that generates an output two-dimensional image by performing image processing on the overlay and the underlay. As illustrated in FIG. 5, the two-dimensional object drawing unit 1363a, A two-dimensional geometric transformation processing unit 1363b and a luminance adjustment unit 1363c are included. For example, the two-dimensional image processing unit 1363 superimposes one overlay on each of nine parallax images (underlays) in order to reduce the load required to generate a two-dimensional image for output. Thus, nine output two-dimensional images are generated.

  The two-dimensional object drawing unit 1363a is a processing unit that draws various information drawn on the overlay, and the two-dimensional geometric transformation processing unit 1363b performs parallel movement processing or rotational movement processing on the position of the various information drawn on the overlay. Or a processing unit that performs an enlargement process or a reduction process of various types of information drawn on the overlay.

  The luminance adjustment unit 1363c is a processing unit that performs luminance conversion processing. For example, the gradation of an output destination stereoscopic display monitor, an image such as a window width (WW: Window Width), a window level (WL: Window Level), or the like. This is a processing unit that adjusts the brightness of the overlay and the underlay according to the processing parameters.

  The output two-dimensional image generated in this way is temporarily stored in the storage unit 134 by the control unit 135, for example, and then transmitted to the image storage device 120 via the communication unit 133. For example, when the terminal device 140 acquires the two-dimensional image for output from the image storage device 120, converts it to an intermediate image arranged in a predetermined format (for example, a lattice shape), and displays it on a stereoscopic display monitor, A doctor or a laboratory technician can view a stereoscopically viewable medical image in a state where various types of information (scale, patient name, examination item, etc.) are drawn. Alternatively, the output two-dimensional image is directly transmitted to the terminal device 140 by the control unit 135 via the communication unit 133, for example.

  As described above, the terminal device 140 according to the first embodiment is a device that allows a doctor or laboratory technician working in a hospital to view a medical image, and is rendered from the image storage device 120 or the workstation 130. The parallax image group (two-dimensional image for output) generated by the processing unit 136 is acquired. FIG. 7 is a diagram for explaining a configuration example of the terminal device according to the first embodiment.

  As illustrated in FIG. 7, the terminal device 140 according to the first embodiment includes an input unit 141, a display unit 142, a communication unit 143, a storage unit 144, a control unit 145, and a two-dimensional image processing unit 146. And have.

  The input unit 141 is a mouse, a keyboard, a trackball, or the like, and receives input of various operations on the terminal device 140 from an operator. Specifically, the input unit 141 according to the first embodiment receives a stereoscopic request from the operator. For example, the input unit 141 accepts input of patient ID, examination ID, device ID, series ID, and the like for designating volume data that the operator desires to display for interpretation as a stereoscopic request.

  The display unit 142 is a liquid crystal panel or the like as a stereoscopic display monitor, and displays various types of information. Specifically, the display unit 142 according to the first embodiment displays a GUI (Graphical User Interface) for receiving various operations from the operator, a stereoscopic image, and the like. For example, the display unit 142 is a 2-parallax monitor or a 9-parallax monitor. Below, the case where the display part 142 is a 9 parallax monitor is demonstrated.

  The communication unit 143 is a NIC (Network Interface Card) or the like, and performs communication with other devices. For example, the communication unit 143 according to the first embodiment transmits information regarding the stereoscopic request received by the input unit 141 to the image storage device 120. Further, the communication unit 143 according to the first embodiment receives a parallax image group or the like transmitted by the image storage device 120 or the workstation 130 in response to a stereoscopic view request.

  The storage unit 144 is a hard disk, a semiconductor memory element, or the like, and stores various types of information. Specifically, the storage unit 144 according to the first embodiment stores a parallax image group acquired from the image storage device 120 or the workstation 130 via the communication unit 143. The storage unit 144 also stores incidental information (the number of parallaxes, resolution, and the like) of the parallax image group acquired from the image storage device 120 or the workstation 130 via the communication unit 143.

  The control unit 145 is an electronic circuit such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), or an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). Take control.

  For example, the control unit 145 transmits / receives information regarding a stereoscopic request made to / from the image storage device 120 via the communication unit 143, and communicates with the image storage device 120 or the workstation 130 via the communication unit 143. Controls transmission / reception of a parallax image group and the like to be performed. For example, the control unit 145 controls storage of the parallax image group or the like in the storage unit 144 and reading of the parallax image group or the like from the storage unit 144.

  In addition, the control unit 145 according to the first embodiment controls the display of the GUI and the display of the parallax image group on the display unit 142. The control unit 145 according to the first embodiment converts the parallax image group into an intermediate image arranged in a predetermined format (for example, a lattice shape), and displays the intermediate image on the display unit 142 which is a 9-parallax monitor.

  Further, the control unit 145 according to the first embodiment controls image processing by the two-dimensional image processing unit 146.

  The two-dimensional image processing unit 146 has the same function as the two-dimensional image processing unit 1363 described with reference to FIG. That is, the two-dimensional image processing unit 146 generates an overlay on the parallax image group as the underlay generated by the three-dimensional image processing unit 1362 and superimposes the two-dimensional image for output to the display unit 142. An image can be generated.

  As described above, the rendering processing unit 136 generates a parallax image group from the volume data under the control of the control unit 135. In addition, the terminal device 140 acquires a parallax image group and displays it on the display unit 142. As a result, a doctor or laboratory technician who is an operator of the terminal device 140 can browse a stereoscopically viewable medical image in a state where various information (scale, patient name, examination item, etc.) is drawn.

  However, in response to a request (rotation or enlargement / reduction of the volume data, panorama display, clipping, etc.) via the input unit 141 by the operator of the terminal device 140 (observer of the display unit 142), 9 parallax images are obtained from the volume data. When the processing to be generated is executed in real time, it is difficult to display an interactive processing result to the observer due to the large amount of calculation of the volume rendering processing.

  That is, in order to generate a 9-parallax image in real time according to the change of the rendering condition, the workstation 130 is required to have a high image processing capability. For this reason, depending on the image processing capability of the workstation 130, there will be a time difference from when the request is input by the observer until the display of the nine parallax images. Note that the above problem similarly occurs even when the observer is an observer of the display unit 132 (an operator of the workstation 130).

  For example, the operator of the terminal device 140 sets a reference viewpoint in the coordinate system of the medical image diagnostic apparatus 110 that has generated the volume data, and uses eight viewpoints with a parallax angle of 1 degree from the reference viewpoint. Thus, it is required to generate nine parallax images by the parallel projection method. The nine parallax images generated by the workstation 130 in response to the request are displayed on the display unit 142 and referred to by the operator of the terminal device 140. FIG. 8 is a diagram for explaining an example of a rendering condition change request.

  Further, when the operator of the terminal device 140 wants to refer to the volume data from different angles, for example, as shown in FIG. 8A, the position of the viewpoint when performing volume rendering is input via the input unit 141. Make a change request. In the example shown in FIG. 8A, the operator of the terminal device 140 searches the viewpoint position that the terminal device 140 wants to refer to by rotating the viewpoint on the XY plane or rotating the viewpoint on the XZ plane.

  The request is transmitted from the communication unit 143 to the communication unit 133 under the control of the control unit 145, and further transferred from the communication unit 133 to the control unit 135. The control unit 135 controls the rendering processing unit 136 so as to generate a parallax image group (9 parallax images) by performing processing that matches the transferred request. For example, as shown in FIG. 8B, in accordance with the rotational movement of the viewpoint, the rendering processing unit 136 causes the “reference viewpoint (see the hatched circle in the figure) and the white outline in the eight viewpoint diagrams. 9 ”is newly set sequentially, and volume rendering processing by parallel projection is performed to sequentially generate 9 parallax images. The nine parallax images (images (1) to (9)) are sequentially converted into intermediate images in the terminal device 140 and output to the display unit 142, as shown in (C) of FIG.

  However, for example, when a request for rotational movement is made in a short time, the generation of 9 parallax images at different viewpoint positions shown in FIG. A delay will occur with respect to the request of the person. Note that FIG. 8 is merely an example, and as a rendering condition change request, a viewpoint position translation request, a projection method change request, a parallax angle change request, a parallax number change request, a parallax image group change request, There is a request for scaling. The generation of the parallax image group is also delayed with respect to the observer's request depending on the magnitude of the change amount per unit time of the change request.

  Therefore, the workstation 130 according to the first embodiment performs rendering processing control of the control unit 135 so as to generate a stereoscopic image according to the request of the observer in a time that does not give stress to the observer. Done.

  That is, the control unit 135 according to the first embodiment generates a parallax image group, which is a parallax image having a predetermined number of parallaxes displayed on the stereoscopic display monitor, by rendering processing from volume data that is three-dimensional medical image data. The following control is performed on the rendering processing unit 136. Specifically, the control unit 135 according to the first embodiment displays an image related to the data amount of the parallax image group according to the amount of change regarding the rendering condition changing operation by the operator who refers to the stereoscopic display monitor. The rendering processing unit 136 is controlled to change the generation parameter.

  More specifically, the control unit 135 according to the first embodiment changes the resolution of the parallax image group as an image generation parameter according to the amount of change. More specifically, the control unit 135 according to the first embodiment changes the density of the projection light (Ray) set when generating the parallax image group according to the magnitude of the change amount. 9 and 10 are diagrams for explaining an example of the rendering control process of the control unit according to the first embodiment.

  For example, as shown in FIG. 9, the control unit 135 sets a low resolution (Low Resolution), a medium resolution (Middle Resolution), and a high resolution (High Resolution) as the resolution level. “Level: low resolution”, as shown in FIG. 9A, sets a low-resolution parallax image group generated from volume data by setting the projection light irradiated from the viewpoint to the projection plane at a low density. Is. In addition, “level: medium resolution” indicates that a group of parallax images generated from volume data is set to medium resolution by setting the projection light irradiated from the viewpoint to the projection surface at medium density, as shown in FIG. 9B. It is what.

  In addition, “level: high resolution” indicates that the parallax image group generated from the volume data is set to high resolution by setting the projection light to be projected from the viewpoint to the projection plane at a high density as shown in FIG. To do. For example, the control unit 135 normally sets the projection light density for generating a parallax image group that matches the resolution of the image optimally displayed on the display unit 142 as the “level: high resolution” projection light density. . In FIG. 9, the case where the projection light is parallel light used in the parallel projection method has been described. However, the change in resolution accompanying the change in the projection light density is also applicable when the projection light is a radial light beam used in the perspective projection method.

  The control unit 135 transmits the nine parallax images generated based on the initial conditions to the terminal device 140, and then, for example, the rendering condition of the operator using the input unit 141 via the communication unit 143 and the communication unit 133. Get the amount of change per unit time of the change operation. Specifically, in the control unit 135, the operator inputs a scroll bar for rotational movement, a scroll bar for parallel movement, a scroll bar for enlargement / reduction, and the like displayed as a GUI on the display unit 142. The amount of movement of the rendering condition change operation input by operating with the mouse is acquired together with the time information. Alternatively, for example, the control unit 135 includes an input unit 141 for a scroll bar for changing the number of parallaxes displayed on the display unit 142 as a GUI, a scroll bar for changing the parallax angle, a projection method changeover switch, and the like. The amount of movement of the rendering condition change operation input by operating with the mouse is acquired together with the time information. As a result, the control unit 135 acquires the amount of change in the movement amount per unit time. When the amount of change exceeds a predetermined threshold, the control unit 135 reduces the data amount (resolution) of the parallax image group, and when the amount of change is equal to or less than the predetermined threshold after performing the data amount reduction control, The resolution that is the image generation parameter is changed so that the data amount (resolution) of the parallax image group is returned to the data amount (resolution) before the reduction.

  As an example, the control unit 135 changes the amount of change in viewpoint position movement (such as rotational movement) per unit time while the amount of change in viewpoint position movement amount (such as rotational movement amount) per unit time is large. Is large, the volume rendering process is executed with a coarse resolution. Thereafter, for example, when the amount of change becomes small as the user operation is completed, the volume rendering process is executed at a high resolution.

  Here, in the first embodiment, the control unit 135 uses a plurality of threshold values as the predetermined threshold value. That is, the control unit 135 according to the first embodiment sets the first threshold value and the second threshold value as threshold values for the amount of change because the resolution level has three levels.

  For example, as illustrated in FIG. 10, when “0 ≦ change amount <first threshold value”, the control unit 135 generates a parallax image group whose resolution level is “high resolution (High)”. Further, as illustrated in FIG. 10, when “first threshold ≦ change amount <second threshold”, the control unit 135 generates a parallax image group having a resolution level of “Middle”. In addition, as illustrated in FIG. 10, when “second threshold ≦ amount of change”, the control unit 135 generates a parallax image group whose resolution level is “low resolution (Low)”.

  That is, the rendering processing unit 136 generates a parallax image group with reduced resolution so that the processing load is reduced under the control of the control unit 135 when the frequency of changing the rendering condition requested by the observer is high. . Also, the rendering processing unit 136 has a processing load that can respond to the request of the observer under the control of the control unit 135 when the frequency of changing the rendering condition requested by the observer is low. A parallax image group returned to the resolution is generated.

  Next, processing of the image processing system 1 according to the first embodiment will be described with reference to FIG. FIG. 11 is a flowchart for explaining the rendering control processing of the workstation according to the first embodiment.

  As illustrated in FIG. 11, the workstation 130 of the image processing system 1 according to the first embodiment determines whether or not a stereoscopic display request has been received from the operator of the terminal device 140 (step S <b> 101). Here, when the display request is not accepted (No at Step S101), the workstation 130 waits until the display request is accepted.

  On the other hand, when a display request is received (Yes at Step S101), the control unit 135 performs control so as to generate a high-resolution nine-parallax image (Step S102). Then, the control unit 135 starts to acquire the amount of change related to the rendering condition changing operation by the operator of the terminal device 140 transferred via the communication unit 133 (step S103). For example, the control unit 135 calculates the amount of change per unit time (1 second) by acquiring the movement amount of the rendering condition change operation every “0.2 seconds”.

  Then, the control unit 135 determines whether or not the amount of change is less than the first threshold (step S104). Here, when the amount of change is less than the first threshold (Yes at Step S104), the control unit 135 performs control so as to generate a high-resolution nine-parallax image (Step S105).

  On the other hand, when the amount of change is greater than or equal to the first threshold (No at Step S104), the control unit 135 determines whether or not the amount of change is less than the second threshold (Step S106). Here, when the amount of change is less than the second threshold (Yes at Step S106), the control unit 135 performs control so as to generate a medium-resolution nine-parallax image (Step S107).

  On the other hand, when the amount of change is equal to or greater than the second threshold (No at Step S106), the control unit 135 performs control so as to generate a low-resolution nine-parallax image (Step S106).

  After the process of step S105, step S107, or step S108, the control unit 135 determines whether a display end request has been received (step S109). Here, when the display end request is not accepted (No at Step S109), the control unit 135 returns to Step S104 and performs a comparison process between the next obtained change amount and the first threshold value.

  On the other hand, when the display end request is received (Yes at Step S109), the control unit 135 ends the rendering control process.

  As described above, in the first embodiment, the resolution of the parallax image group is changed according to the amount of change in the rendering condition changing operation of the observer. That is, in the first embodiment, during the period when the observer frequently changes the rendering condition, the observer can determine whether or not a stereoscopic image to be interpreted is displayed although the resolution is coarse. Can be generated and displayed smoothly. In addition, when the observer determines that the stereoscopic image to be interpreted is displayed, an image with the resolution restored can be generated and displayed smoothly. Therefore, in the first embodiment, an image for stereoscopic viewing according to the request of the observer can be generated in a time that does not give stress to the observer.

  In the first embodiment, since the resolution level is set in multiple stages, a plurality of threshold values used for level change are set, so that the granularity of data amount control can be improved.

(Second Embodiment)
In the second embodiment, a case will be described in which change control of an image generation parameter related to the data amount is performed by a method different from the first embodiment.

  The control unit 135 according to the second embodiment changes the number of images constituting the parallax image group (number of parallaxes) as an image generation parameter according to the amount of change. 12, 13, 14-1, and 14-2 are diagrams for explaining an example of the rendering control process of the control unit according to the second embodiment.

  For example, as illustrated in FIG. 12, the control unit 135 sets 3 parallaxes, 5 parallaxes, and 9 parallaxes as the level of the number of parallaxes. “Level: 3 parallax”, as shown in FIG. 12A, generates a parallax image group (3 parallax images) from volume data from three viewpoints having a designated parallax angle between parallax images. It is something to be made. In addition, “level: 5 parallax” is a group of parallax images (5 parallax images) from volume data based on five viewpoints having a designated parallax angle between parallax images, as shown in FIG. Is generated.

  In addition, “level: 9 parallax” is a group of parallax images (9 parallax images) from volume data based on nine viewpoints that have designated parallax angles between parallax images, as shown in FIG. Is generated. That is, “level: 9 parallax” is to generate the upper limit number of images that can be simultaneously displayed on the display unit 142.

  For example, the control unit 135 reduces the number of images generated by the volume rendering process while the amount of change, which is the movement amount (rotational movement or the like) of the viewpoint position per unit time, is large. After that, for example, when the amount of change decreases with the completion of the user operation, the number of images generated by the volume rendering process is returned to the normal number of images. As described above, the amount of change is a change per unit time of a request for translation of the viewpoint position, a request for changing the projection method, a request for changing the parallax angle, a request for changing the number of parallaxes, and a request for changing the number of parallax images. It may be an amount.

  That is, the control unit 135 reduces the number of images of the parallax image group when the change amount exceeds the predetermined threshold value, and when the change amount becomes equal to or smaller than the predetermined threshold value after performing the data amount reduction control, The number of images (the number of parallaxes), which is an image generation parameter, is changed so that the number of images is returned to the number of images before reduction.

  Here, also in the second embodiment, the control unit 135 uses a plurality of thresholds as the predetermined threshold. That is, the control unit 135 according to the second embodiment sets the first threshold value and the second threshold value as threshold values for the amount of change because the level of the number of images is three levels.

  For example, as illustrated in FIG. 13, the control unit 135 generates nine parallax images when “0 ≦ change amount <first threshold value”. In addition, as illustrated in FIG. 13, the control unit 135 generates a 5-parallax image when “first threshold ≦ change amount <second threshold”. In addition, as illustrated in FIG. 10, the control unit 135 generates a three-parallax image when “second threshold ≦ change amount”.

  That is, the rendering processing unit 136 generates a parallax image group in which the number of parallaxes is reduced under the control of the control unit 135 so that the processing load is reduced when the rendering condition requested by the observer is frequently changed. To do. In addition, the rendering processing unit 136 has a processing load that can respond to the request of the observer under the control of the control unit 135 when the frequency of changing the rendering condition requested by the observer is low. A group of parallax images returned to the normal number of parallaxes is generated.

  In addition, said 3 parallax image is corresponded to image (4)-(6) in image (1)-(9) shown to (C) of FIG. When the control unit 135 generates a three-parallax image, as illustrated in (A) of FIG. 14A, as an image instead of the images (1) to (3) and the images (7) to (9), for example, The rendering processing unit 136 generates an image B in which the color of all pixels is black. Then, the control unit 135 causes the terminal device 140 to transmit the image group as a 9-parallax image. As illustrated in FIG. 14A, the control unit 145 of the terminal device 140 converts the received nine parallax images into “image B, image B, image B”, “image (4), and image (5)”. , “Image (6)” and “Image B, Image B, Image B” are converted into intermediate images arranged in three rows and three columns and output to the display unit 142.

  Moreover, said 5 parallax image is corresponded to image (3)-(7) in image (1)-(9) shown to (C) of FIG. When the control unit 135 generates a five-parallax image, as illustrated in (B) of FIG. 14A, the image B is used as an image instead of the images (1), (2), (8), and (9). Is generated by the rendering processing unit 136. Then, the control unit 135 causes the terminal device 140 to transmit the image group as a 9-parallax image. As illustrated in FIG. 14B, the control unit 145 of the terminal device 140 converts the received nine parallax images into “image B, image B, image (3)”, “image (4), image ( 5), “Image (6)” and “Image (7), Image B, Image B”, which are converted into intermediate images arranged in three rows and three columns, and output to the display unit 142.

  Here, in the example illustrated in FIG. 14A, the control unit 135 uses the viewpoint moved by the operator of the terminal device 140 as a reference viewpoint, and becomes a disparity angle with a specified disparity angle around the reference viewpoint 2 By setting one viewpoint or four viewpoints, a three-parallax image (images (4) to (6)) or a five-parallax image (images (3) to (7)) is generated. Such a 3-parallax image and 5-parallax image are a group of stereoscopic images suitable for the case where the operator observes the display unit 142 at a directly facing position. That is, the 3 parallax image and the 5 parallax image are images that can be stereoscopically viewed when the line-of-sight direction of the operator is perpendicular to the display unit 142. In other words, the “parallax image group in which the number of parallaxes is reduced” illustrated in FIG. 14A is an image group that cannot be stereoscopically viewed by an operator whose viewing direction is a direction other than the vertical direction with respect to the display unit 142. There is.

  Therefore, the control unit 135 according to the second embodiment may perform the control described below on the rendering processing unit 136. That is, when changing the number of images (number of parallaxes) as the image generation parameter, the control unit 135 generates a parallax image group according to the line-of-sight direction of the operator (observer) with respect to the stereoscopic monitor (display unit 142). The rendering processing unit 136 is controlled so as to change the viewpoint position. For example, the control unit 135 acquires the line-of-sight direction of the operator with respect to the display unit 142 using a camera having a face recognition function attached to the display unit 142. For example, the camera tracks (tracks) the face of the operator in the real space by the face recognition function, and further determines the line-of-sight direction with respect to the display unit 142 of the operator from the recognized face direction. The line-of-sight direction acquired by the camera is transferred to the control unit 135 via the communication unit 143 and the communication unit 133.

  Here, for example, when the line-of-sight direction is the direction facing the display unit 142 and “second threshold ≦ amount of change”, the control unit 135 specifies the parallax angle centered on the reference viewpoint. By setting two viewpoints to be parallax angles, three parallax images (images (4) to (6)) are generated as shown in FIG. Further, the control unit 135 generates an image B as an image instead of the images (1) to (3) and the images (7) to (9).

  Alternatively, when the line-of-sight direction is the direction facing the display unit 142 and “first threshold ≦ change amount <second threshold”, the control unit 135 designates the parallax angle around the reference viewpoint. By setting four viewpoints to be the parallax angles, five parallax images (images (3) to (7)) are generated as shown in FIG. Further, the control unit 135 generates an image B as an image instead of the images (1), (2), (8), and (9).

  On the other hand, as illustrated in FIG. 14B, when the acquired line-of-sight direction is not directly facing the display unit 142, the control unit 135 determines a viewpoint position for performing volume rendering according to the line-of-sight direction. Change it. Specifically, the control unit 142 renders a rendering processing unit so that a parallax image group that should originally be observed by an operator who refers to the 9 parallax images is generated at a position centered on the acquired line-of-sight direction. 136 is controlled.

  When “second threshold ≦ change amount”, the control unit 135, for example, as illustrated in FIG. 14B according to the angle between the acquired line-of-sight direction and the direction facing the display unit 142. As described above, a three-parallax image “image (2), image (3), and image (4)” is generated. Furthermore, the control unit 135 generates an image B as an image instead of the image (1) and the images (5) to (9).

  Alternatively, when “first threshold ≦ change amount <second threshold”, the control unit 135 determines, for example, according to the angle between the acquired line-of-sight direction and the direction facing the display unit 142, for example, FIG. As shown in (B) of FIG. 5, a five-parallax image “image (1), image (2), image (3), image (4) and image (5)” is generated. Further, the control unit 135 generates an image B as an image instead of the images (6) to (9).

  As described above, when performing the change control of the number of parallaxes, the operator further performs the change control of the viewpoint position at the time of rendering in accordance with the line-of-sight direction with respect to the display unit 142, so that the operator The group of images can be reliably referred to on the display unit 142. Note that the line-of-sight direction acquisition process may be performed by attaching a position sensor such as a magnetic sensor to the operator and the display unit 142 in addition to the face recognition function.

  Next, processing of the image processing system 1 according to the second embodiment will be described with reference to FIG. FIG. 15 is a flowchart for explaining the rendering control process of the workstation according to the second embodiment.

  As illustrated in FIG. 15, the workstation 130 of the image processing system 1 according to the second embodiment determines whether or not a stereoscopic display request has been received from the operator of the terminal device 140 (step S <b> 201). Here, when the display request is not accepted (No at Step S201), the workstation 130 waits until the display request is accepted.

  On the other hand, when a display request is received (Yes at Step S201), the control unit 135 performs control so as to generate a nine-parallax image (Step S202). Then, the control unit 135 starts acquisition of a change amount related to the rendering condition changing operation by the operator of the terminal device 140 transferred via the communication unit 133 (step S203).

  Then, the control unit 135 determines whether or not the amount of change is less than the first threshold (step S204). Here, when the amount of change is less than the first threshold (Yes at Step S204), the control unit 135 performs control so as to generate a nine-parallax image (Step S205).

  On the other hand, when the amount of change is greater than or equal to the first threshold (No at Step S204), the control unit 135 determines whether or not the amount of change is less than the second threshold (Step S206). Here, when the amount of change is less than the second threshold (Yes at Step S206), the control unit 135 performs control so as to generate a 5-parallax image (Step S207).

  On the other hand, when the amount of change is equal to or greater than the second threshold (No at Step S206), the control unit 135 performs control to generate a three-parallax image (Step S206).

  After the process of step S205, step S207, or step S208, the control unit 135 determines whether a display end request has been received (step S209). Here, when the display end request is not accepted (No at Step S209), the control unit 135 returns to Step S204 and performs a comparison process between the next obtained change amount and the first threshold value.

  On the other hand, when the display end request is received (Yes at Step S209), the control unit 135 ends the rendering control process.

  As described above, in the second embodiment, the number of images in the parallax image group is changed in accordance with the amount of change in the rendering condition changing operation of the observer. That is, in the second embodiment, during the period in which the observer frequently changes the rendering condition, whether or not a stereoscopic image to be interpreted is displayed, although the number of stereoscopically viewable image pairs decreases due to motion parallax. It is possible to smoothly generate and display an image that allows an observer to determine whether or not. Further, at the time when the observer determines that the stereoscopic image to be interpreted is displayed, all image pairs that can be changed with motion parallax can be smoothly generated and displayed on the stereoscopic monitor. Therefore, in the second embodiment, as in the first embodiment, a stereoscopic image according to the request of the observer can be generated in a time that does not give stress to the observer.

  In the second embodiment, since the number of images is set to multiple levels, a plurality of threshold values used for level change are set, so that the granularity of data amount control can be improved.

  In addition, said 1st and 2nd embodiment may be a case where the modification illustrated in FIG. 16 is performed. FIG. 16 is a diagram for explaining a modification of the first embodiment and the second embodiment.

  In the first embodiment and the second embodiment, the case where the data amount change level is three stages and two threshold values are used has been described. However, for example, in the first embodiment, as shown in FIG. 16A, two levels of “high resolution (High)” and “low resolution (Low)” are set, and the first threshold is set. It may be executed by using a threshold value. In such a case, as illustrated in FIG. 16A, the control unit 135 generates a parallax image group whose resolution level is “High resolution” when “0 ≦ change amount <first threshold value”. Let Further, as illustrated in FIG. 16A, the control unit 135 generates a parallax image group whose resolution level is “low resolution (Low)” when “first threshold ≦ change amount”.

  Further, for example, as shown in FIG. 16B, the second embodiment is executed by setting two levels of “9 parallax” and “3 parallax” and using the first threshold as the threshold. It may be the case. In such a case, as illustrated in FIG. 16B, the control unit 135 generates a nine-parallax image when “0 ≦ change amount <first threshold value”. In addition, as illustrated in FIG. 16B, the control unit 135 generates a three-parallax image when “first threshold ≦ change amount”.

  Further, each of the first embodiment and the second embodiment may be a case where the data amount change level is four or more levels, and three or more threshold values are used.

  Further, the data amount change control may be executed by using both the resolution and the number of parallaxes. For example, as illustrated in FIG. 16C, the control unit 135 generates a nine-parallax image with a resolution level of “High” when “0 ≦ change amount <first threshold”. . In addition, as illustrated in FIG. 16C, the control unit 135 displays a five-parallax image having a resolution level of “high resolution (Middle)” when “first threshold ≦ change amount <second threshold”. Generate. Further, as illustrated in FIG. 16C, the control unit 135 generates a three-parallax image having a resolution level of “low resolution (Low)” when “first threshold ≦ amount of change”.

  Furthermore, the data amount change control may be executed by using the resolution and the number of parallaxes in combination to further change the data amount change level. For example, the control unit 135 sets four threshold values from a first threshold value to a fourth threshold value, as shown in FIG. Then, as illustrated in FIG. 16D, the control unit 135 generates a nine-parallax image having a resolution level of “High” when “0 ≦ change amount <first threshold”. . Further, as illustrated in FIG. 16D, the control unit 135, when “first threshold ≦ change amount <second threshold”, has a resolution level of “high resolution (High)”. Generate an image.

  In addition, as illustrated in FIG. 16D, the control unit 135, when “second threshold ≦ change amount <third threshold”, displays a 5-parallax image whose resolution level is “high resolution (Middle)”. Generate. In addition, as illustrated in FIG. 16D, the control unit 135, when “third threshold ≦ change amount <fourth threshold”, displays a 5-parallax image whose resolution level is “low resolution (Low)”. Generate. In addition, as illustrated in FIG. 16D, the control unit 135 generates a three-parallax image having a resolution level of “low resolution (Low)” when “fourth threshold value ≦ change amount”.

  Also in the modification shown in FIG. 16, it is possible to generate an image for stereoscopic viewing according to the request of the observer in a time that does not give stress to the observer.

  In the above embodiment, the case where the control unit 135 of the workstation 130 performs both the change amount acquisition processing and the data amount change control has been described. However, the above embodiment is not limited to this. For example, the control unit 145 of the terminal device 140 may perform change amount acquisition processing, and the control unit 135 of the workstation 130 may perform data amount change control. Alternatively, the control unit 145 of the terminal device 140 may perform both the change amount acquisition process and the data amount change control.

  Further, in the above-described embodiment, the medical image diagnostic apparatus 110 may be the apparatus that performs the rendering process. That is, in the above-described embodiment, the medical image diagnostic apparatus 110 performs change amount acquisition processing and data amount change control, and the observer who is the change amount acquisition target is an operator of the workstation 130 or the terminal device 140. There may be. Further, when the apparatus that performs the rendering process is the medical image diagnostic apparatus 110 and the observer who is the acquisition target of the change amount is the operator of the workstation 130, the control unit 135 performs the change amount acquisition process, and the medical image diagnosis The apparatus 110 may perform data amount change control, or the control unit 135 may perform both change amount acquisition processing and data amount change control. Similarly, when the medical image diagnostic apparatus 110 is the device that performs the rendering process and the observer who is the acquisition target of the change amount is the operator of the terminal device 140, the control unit 145 performs the change amount acquisition process, and the medical image The diagnosis apparatus 110 may perform data amount change control, or the control unit 145 may perform both change amount acquisition processing and data amount change control.

  Further, when “acquisition of change amount, data amount change control and display of parallax image group” described in the above embodiment is performed only by the medical image diagnostic apparatus 110 or only by the workstation 130, the terminal device It may be a case where only 140 is performed.

  That is, the processing described in the above embodiment is configured to be functionally or physically distributed / integrated in an arbitrary unit according to various loads or usage conditions of each device included in the image processing system 1. be able to. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  The image processing method described in the above embodiment can be realized by executing an image processing program prepared in advance on a computer such as a personal computer or a workstation. This image processing program can be distributed via a network such as the Internet. The program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, a DVD, or a Blu-ray Disc (registered trademark), and is read from the recording medium by the computer. Can also be implemented.

  As described above, according to the first embodiment, the second embodiment, and the modification, the stereoscopic image corresponding to the request of the observer is generated in a time that does not stress the observer. Can do.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1 Image processing system 2 Hospital LAN (Local Area Network)
DESCRIPTION OF SYMBOLS 110 Medical diagnostic imaging apparatus 120 Image storage apparatus 130 Workstation 131 Input part 132 Display part 133 Communication part 134 Storage part 135 Control part 136 Rendering process part 140 Terminal apparatus 141 Input part 142 Display part 143 Communication part 144 Storage part 145 Control part 146 2D image processor

Claims (8)

A rendering processing unit that generates a parallax image group, which is a parallax image having a predetermined number of parallaxes, displayed by a stereoscopic display device from volume data, which is three-dimensional medical image data, by rendering processing;
The rendering processing unit is controlled to change an image generation parameter related to the data amount of the parallax image group according to a change frequency per unit time of a change operation of a rendering condition by an operator who refers to the stereoscopic display device. A control unit;
An image processing system comprising: When the change frequency exceeds a predetermined threshold, the control unit reduces the data amount of the parallax image group, and after performing the data amount reduction control, when the change frequency becomes equal to or less than the predetermined threshold, The image processing system according to claim 1, wherein the image generation parameter is changed so that the data amount of the parallax image group is returned to the data amount before reduction.   The image processing system according to claim 2, wherein the control unit uses a plurality of threshold values as the predetermined threshold value. The image processing system according to claim 1, wherein the control unit changes the resolution of the parallax image group as the image generation parameter according to the magnitude of the change frequency. . The said control part changes the number of images which comprise the said parallax image group as said image generation parameter according to the magnitude | size of the said change frequency , The Claim 1 characterized by the above-mentioned. Image processing system. A rendering processing unit that generates a parallax image group, which is a parallax image having a predetermined number of parallaxes, displayed by a stereoscopic display device from volume data, which is three-dimensional medical image data, by rendering processing;
A change frequency per unit time of a rendering condition change operation by an operator who refers to the stereoscopic display device is acquired, and an image generation parameter related to the data amount of the parallax image group is changed according to the acquired change frequency. A control unit for controlling the rendering processing unit,
An image processing apparatus comprising: The stereoscopic display device is referred to a rendering processing unit that generates a parallax image group that is a parallax image having a predetermined number of parallax images displayed on the stereoscopic display device from volume data that is three-dimensional medical image data. A control step for controlling to change an image generation parameter related to a data amount of the parallax image group according to a change frequency per unit time of a rendering condition change operation by an operator;
An image processing method comprising: The stereoscopic display device is referred to a rendering processing unit that generates a parallax image group that is a parallax image having a predetermined number of parallax images displayed on the stereoscopic display device from volume data that is three-dimensional medical image data. A control procedure for controlling to change an image generation parameter related to the data amount of the parallax image group according to a change frequency per unit time of a change operation of rendering conditions by an operator;
An image processing program for causing a computer to execute.

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