JP6210739B2 - Image processing apparatus and medical image diagnostic apparatus - Google Patents

Description

  Embodiments described herein relate generally to an image processing apparatus and a medical image diagnostic apparatus.

  Conventionally, various image processing has been performed to make it easier to observe an observation target included in an image. For example, in an image including a linear signal as an observation target, the linear signal is separated from a signal other than the linear signal (for example, the background) to enhance the linear signal or suppress the signal other than the linear signal. Such image processing is known. As an example, an image processing method is known in which a linear signal is detected from an image and enhancement processing is performed on the detected linear signal.

  By using the image processing method described above, for example, a linear structure such as a catheter can be accurately detected and displayed in a fluoroscopic image captured by an X-ray diagnostic apparatus. However, in the above-described prior art, there is a certain limit in detecting a linear signal included in an image.

JP 2001-111835 A

  The problem to be solved by the present invention is to provide an image processing apparatus and a medical image diagnostic apparatus that can improve the accuracy of detection of a linear signal included in an image.

An image processing apparatus according to an embodiment includes an image data acquisition unit and a signal detection unit. The image data acquisition means acquires medical image data including a linear device image . The signal detection means sets a signal detection area including independent detection ranges at both ends in the longitudinal direction at each of a plurality of positions in the medical image data in a plurality of directions, and detects a signal in each of the detection ranges. when, signal included in the signal detecting region by judging that the linear signal to detect the linear signal included in the medical image data.

FIG. 1 is a diagram illustrating an example of a configuration of an image processing system according to the first embodiment. FIG. 2 is a diagram for explaining an example of detection of a linear signal according to the related art. FIG. 3 is a diagram illustrating an example of the configuration of the image processing apparatus according to the first embodiment. FIG. 4 is a diagram for explaining an example of linear signal detection by the signal detection unit according to the first embodiment. FIG. 5 is a flowchart illustrating a processing procedure performed by the image processing apparatus according to the first embodiment. FIG. 6 is a diagram for explaining processing by the display image generation unit according to the second embodiment. FIG. 7 is a diagram for explaining an example of enhancement processing by the display image generation unit according to the second embodiment. FIG. 8 is a diagram illustrating an example of the shape of a template according to the third embodiment. FIG. 9 is a diagram for explaining a modification according to the third embodiment.

(First embodiment)
Details of the image processing apparatus according to the present application will be described below. In the first embodiment, an image processing system including the image processing apparatus according to the present application will be described as an example. FIG. 1 is a diagram illustrating an example of a configuration of an image processing system 1 according to the first embodiment.

  As illustrated in FIG. 1, the image processing system 1 according to the first embodiment includes an image processing device 100, a medical image diagnostic device 200, and an image storage device 300. Each apparatus illustrated in FIG. 1 is in a state where it can communicate with each other directly or indirectly by, for example, a hospital LAN (Local Area Network) 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 medical image diagnostic apparatus 200 includes, for example, 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). A 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. Then, the medical image diagnostic apparatus 200 collects medical images according to the operations of the respective engineers.

  The medical image diagnostic apparatus 200 transmits the collected image data to the image processing apparatus 100 or the image storage apparatus 300. The medical image diagnostic apparatus 200 identifies, for example, a patient ID that identifies a patient, an examination ID that identifies an examination, and the medical image diagnostic apparatus 200 as supplementary information when transmitting image data to the image storage apparatus 300. A device ID, a series ID for identifying one shot by the medical image diagnostic apparatus 200, and the like are transmitted.

  The image storage device 300 is a database that stores medical images. Specifically, the image storage apparatus 300 stores the image data transmitted from the medical image diagnostic apparatus 200, the incidental information of each image data, and the like in the storage unit and stores them.

  The image processing apparatus 100 acquires image data from the medical image diagnostic apparatus 200 or the image storage apparatus 300, and executes image processing that improves the accuracy of detection of a linear signal included in the image. Here, the accuracy of detection of a linear signal included in an image in the conventional technique will be described. As described above, in the prior art, in order to make it easy to observe the linear signal, the linear signal included in the image data is detected, and the detected linear signal is subjected to enhancement processing, or linear For example, suppression processing is performed on signals other than signals. Here, the conventional technique has a certain limit in the accuracy of detection of the linear signal.

FIG. 2 is a diagram for explaining an example of detection of a linear signal according to the related art. For example, in the prior art, as shown in FIG. 2A, a linear signal is detected by template matching using a rectangular template. For example, in the conventional technology, as shown in FIG. 2A, the template is rotated in 16 directions of M _{0 to} M ₁₅ for each pixel, and pixels of pixels included in the template at each position. A linear signal is detected based on the value. That is, in the prior art, an average value of pixel values of pixels included in the template is calculated at each of the template positions M _{0 to} M ₁₅ , and a linear signal is detected based on the calculated average value.

For example, when the detection target is a linear shadow of only the black-side signal, a template M ₉ whose pixel value average is the minimum value M _min is extracted as shown in FIG. Then, as shown in FIG. 2 (B), the average vector of the extracted region of the template M ₉ by calculating the to calculate the direction and strength of the linear shadow. In the detection of the linear shadow (linear signal), all the linear signals included in the image data are detected by executing the above-described processing for all the pixels.

  Here, in the prior art, when there is a large noise near the center of the rectangular template, the noise may be detected as a linear signal. If enhancement processing is performed on the noise, the noise may be detected. It will be emphasized. Thus, in the prior art, there is a certain limit in the accuracy of detecting a linear signal. Therefore, the image processing apparatus 100 according to the first embodiment improves the accuracy of detection of a linear signal with a detailed configuration described below.

  FIG. 3 is a diagram illustrating an example of the configuration of the image processing apparatus 100 according to the first embodiment. As illustrated in FIG. 3, the image processing apparatus 100 includes an input unit 110, a display unit 120, a communication unit 130, a storage unit 140, and a control unit 150. For example, the image processing apparatus 100 is a workstation, an arbitrary personal computer, or the like, and is connected to the medical image diagnostic apparatus 200, the image storage apparatus 300, and the like via a network.

  The input unit 110 is a mouse, a keyboard, a trackball, or the like, and receives input of various operations on the image processing apparatus 100 from an operator. Specifically, the input unit 110 accepts an input for acquiring image data and the like.

  The display unit 120 is a liquid crystal panel or the like as a monitor, and displays various types of information. Specifically, the display unit 120 displays a GUI (Graphical User Interface) for receiving various operations from the operator and a processing result by the control unit 150 described later. The communication unit 130 is a NIC (Network Interface Card) or the like, and performs communication with other devices.

  The storage unit 140 is, for example, a semiconductor memory device such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk, and a medical image acquired by the control unit 150 described later. The image data etc. are stored. The storage unit 140 stores various information used by the control unit 150 described later. For example, the storage unit 140 stores information on a signal detection area used by the control unit 150 (described later) to detect a linear signal. The signal detection area will be described later in detail.

  The control unit 150 is, for example, 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 an image processing apparatus 100 total control is performed. As illustrated in FIG. 3, the control unit 150 includes, for example, a data acquisition unit 151, a signal detection unit 152, and a display image generation unit 153.

  The data acquisition unit 151 acquires data from the medical image diagnostic apparatus 200 or the image storage apparatus 300 via the communication unit 130. Specifically, the data acquisition unit 151 acquires image data or the like from the medical image diagnostic apparatus 200 or the image storage apparatus 300 in accordance with an instruction received from the operator via the input unit 110 and stores it in the storage unit 140. Store. For example, the data acquisition unit 151 acquires image data of a medical image including a linear signal.

  The signal detection unit 152 detects a linear signal included in the image data using a signal detection region including independent detection ranges on both ends in the longitudinal direction. FIG. 4 is a diagram for explaining an example of linear signal detection by the signal detection unit 152 according to the first embodiment. Here, in FIG. 4, (A) in FIG. 4 shows an example of a signal detection region used by the signal detection unit 152. The signal detection region is a template used for template matching when detecting a linear signal (hereinafter, the signal detection region may be referred to as a template). In FIG. 4, (B) and (C) of FIG. 4 show an example of detection of a linear signal using a signal detection region.

  For example, as shown in FIG. 4A, the signal detection unit 152 uses the template 10 having the detection ranges 11 at both ends in the longitudinal direction and the hollow range 12 between the two detection ranges 11. A linear signal is detected. Here, the detection range 11 included in the template 10 means a range in which a signal within the range is detected. The hollow range 12 means a range where no detection is performed even when a signal is present within the range.

The signal detection unit 152 performs template matching of image data using the template 10 as shown in FIG. That is, the signal detection unit 152 rotates the template 10 in 16 directions of M _{0 to} M ₁₅ for each pixel of the image data, and based on the pixel values of the pixels included in the template 10 at each position, the linear signal Is detected. Here, the signal detection unit 152 determines that the signal included in the image data is a linear signal when a signal is detected in each of the detection ranges 11 included independently at both ends in the longitudinal direction in the template 10. To do.

  For example, as shown by A in FIG. 4B, the signal detection unit 152 detects a signal in each of the detection ranges 11 at both ends when template matching is performed by rotating a template at each pixel. If it is determined that a linear signal has been detected. Therefore, when there is a signal in the hollow area 12 as indicated by B in FIG. 4B, the signal detection unit 152 does not detect a signal in the hollow area 12. Further, as indicated by C in FIG. 4B, the signal detection unit 152 does not detect a signal even when there is a signal in one detection range 11.

  Thus, since the signal detection unit 152 according to the first embodiment does not detect a signal in the hollow range 12 of the template 10, even if there is noise at the center of the template ((B) of FIG. 4). In the figure, the state B), the linear signal is not erroneously detected.

  Here, in the template 10 used by the signal detection unit 152, the detection range 11 in the template 10 is determined based on the number of pixels, the ratio, or the size. For example, when the template 10 is determined by the number of pixels, the longitudinal direction is 30 to 40 pixels, the short direction is 3 to 4 pixels, and the hollow range 12 is 10 to 20 pixels. With this number of pixels, for example, the length in the longitudinal direction can be set to the optimum length that can be detected as a straight line when detecting a linear signal, or it is optimal according to the size of noise. A hollow area 12 can be set. These settings may be set according to the type of medical image to be processed, or may be set based on experience.

  Similarly, the structure of the template 10 may be determined by a ratio (eg, the ratio of the length of the hollow region 12 to the length in the longitudinal direction) or by the size (eg, mm). Good. These settings may also be set according to the type of the target medical image as in the case of the number of pixels, or may be set based on experience. In addition, the setting may be switched from the setting of the number of pixels to these settings.

  And the signal detection part 152 calculates the direction and intensity of a linear shadow by calculating the average of the vector in the detection range 11, as shown to (C) of FIG. As described above, the image processing apparatus 100 according to the first embodiment detects a linear signal using the template 10 having the hollow range 12, thereby reducing false detection of noise, and the lines included in the image. The accuracy of detection of the state signal is improved.

  Returning to FIG. 3, the display image generation unit 153 performs enhancement processing or smoothing processing on the linear signal detected by the signal detection unit 152. For example, the display image generation unit 153 emphasizes and displays the linear shadow of the X-ray image. As described above, the image processing apparatus 100 enhances the diagnostic accuracy or allows the procedure to be executed more efficiently by highlighting and displaying the linear signal detected by the signal detection unit 152 with high accuracy. Can do.

  Here, the display image generation unit 153 according to the first embodiment can also generate a display image based on the template 10. For example, the display image generation unit 153 performs addition averaging or weighted averaging on the pixels within the detection range 11 included in the template 10 to enhance only the linear signal and obtain an image with less influence of noise. be able to.

  Next, a processing procedure of the image processing apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart illustrating a processing procedure performed by the image processing apparatus 100 according to the first embodiment. FIG. 5 shows a case where a linear shadow is detected as a linear signal.

  As illustrated in FIG. 5, in the image processing apparatus 100 according to the first embodiment, when the data acquisition unit 151 acquires image data (step S101), the signal detection unit 152 performs template matching for one pixel. Execute (Step S102). Here, the signal detection unit 152 detects a line where a line is detected in the detection range 11 at both ends of the template 10 as a linear shadow (step S103).

  Thereafter, the signal detection unit 152 calculates the direction of the linear shadow by calculating the vector average within the detection range 11 (step S104). Then, the signal detection unit 152 determines whether or not template matching has been executed for all the pixels (step S105). If it is determined that template matching has not been executed for all pixels (No at Step S105), the signal detection unit 152 returns to Step S102 and executes template matching for unprocessed pixels. .

  On the other hand, when it is determined that the template matching has been executed for all the pixels (Yes at Step S105), the display image generation unit 153 generates a display image using the detection result by the signal detection unit 152 (Step S106). ).

  As described above, according to the first embodiment, the data acquisition unit 151 acquires image data. The signal detection unit 152 detects a linear signal included in the image data by using the template 10 including the independent detection ranges 11 on both ends in the longitudinal direction. Therefore, the image processing apparatus 100 according to the first embodiment can suppress erroneous detection of noise in the vicinity of the center of the template 10 and can improve the accuracy of detection of the linear signal included in the image. To.

  Further, according to the first embodiment, when the signal detection unit 152 detects a signal in each of the detection ranges 11 included independently at both ends in the longitudinal direction in the template 10, the signal included in the image data Is a linear signal. Therefore, the image processing apparatus 100 according to the first embodiment can accurately detect a long linear signal instead of a short signal such as noise.

  Further, according to the first embodiment, the template 10 has the detection range 11 in the template determined based on the number of pixels, the ratio, or the size. Therefore, the image processing apparatus 100 according to the first embodiment can cope with various conditions.

  Further, according to the first embodiment, the display image generation unit 153 generates a display image based on the position of the detection range of the template 10. Therefore, the image processing apparatus 100 according to the first embodiment can generate a display image by selectively using the range in the template 10.

  Further, according to the first embodiment, the display image generation unit 153 performs the smoothing process or the enhancement process on the pixels in the detection range 11 included in the template 10. Therefore, the image processing apparatus 100 according to the first embodiment can perform processing only on a true linear signal, and can provide an image that is easier to observe.

(Second Embodiment)
In the first embodiment described above, the case where a linear signal is detected in the detection range 11 of the template 10 and the detected linear signal is emphasized has been described. In the second embodiment, a case will be described in which a linear signal is detected in the detection range 11 and a portion located in the hollow range 12 in the detected linear signal is emphasized. Note that the image processing apparatus 100 according to the second embodiment differs from the image processing apparatus 100 according to the first embodiment in the processing content of the display image generation unit 153. Hereinafter, these will be mainly described.

  When a signal is detected in each of the detection ranges 11 included in the template 10, the display image generation unit 153 according to the second embodiment performs enhancement processing on pixels in a range different from the detection range 11. To do. FIG. 6 is a diagram for explaining processing by the display image generation unit 153 according to the second embodiment. As shown in FIG. 6, the display image generation unit 153 according to the second embodiment emphasizes the signal near the center (hollow range 12) when signals are detected in the detection ranges 11 at both ends.

  FIG. 7 is a diagram for explaining an example of enhancement processing by the display image generation unit 153 according to the second embodiment. For example, as illustrated in FIG. 7A, the display image generation unit 153 according to the second embodiment applies to the pixels included in the hollow area 12 when a linear shadow is detected in the template 10. To execute the emphasis process. In this case, since the display image generation unit 153 emphasizes the true linear shadow, it is possible to provide an image that is easier to observe.

  Further, for example, as shown in FIG. 7B, when a linear pattern generated by noise is included in the hollow area 12 in the template 10, there is no signal in the detection range 11. In the processing of 152, no detection is performed, and the display image generation unit 153 does not emphasize the noise in the hollow range 12.

  In addition, for example, as shown in FIG. 7C, when a linear pattern generated by noise is detected in one of the detection ranges 11 of the template 10, only one is detected, so that signal detection is performed. The unit 152 does not determine that the signal is a linear signal. Therefore, the display image generation unit 153 does not emphasize the pixels in the hollow range 12.

  For example, as shown in FIG. 7D, when a linear pattern generated by noise is detected in both of the detection ranges 11 of the template 10, the signal detection unit 152 detects a linear shadow. It is determined that As a result, the display image generation unit 153 executes an enhancement process for pixels included in the hollow range 12. However, since the hollow area 12 does not include a black signal, even if the enhancement process is executed, signals other than the linear shadow are not enhanced.

  As described above, according to the second embodiment, when a signal is detected in each of the detection ranges 11 included in the template 10, the display image generation unit 153 has pixels in a range different from the detection range 11. The emphasis process is executed for. Therefore, the image processing apparatus 100 according to the second embodiment can emphasize a signal only when it is a linear signal, and can suppress unnecessary signal enhancement.

(Third embodiment)
Although the first and second embodiments have been described above, the present invention may be implemented in various different forms other than the first and second embodiments described above.

  In the first and second embodiments described above, the case where a rectangular template is used as the template 10 has been described as an example. However, the embodiment is not limited to this, and templates having various shapes may be used. FIG. 8 is a diagram illustrating an example of the shape of the template 10 according to the third embodiment. In FIG. 8, the squares constituting the template 10 indicate one pixel.

  For example, as illustrated in FIG. 8A, the template 10 may have an ellipse detection range as the detection range 11. Further, for example, as illustrated in FIG. 8B, the template 10 may have a triangular detection range as the detection range 11. For example, as illustrated in FIG. 8C, the template 10 may have a fan-shaped detection range as the detection range 11. By using such a template, the signal detection unit 152 can detect not only a straight line but also a curved linear signal.

  Further, as shown in FIG. 8D, a case where two templates (sub-templates 10a and 10b) function as one template 10 in pairs may be used. In such a case, the signal detection unit 152 performs pattern matching using each of the sub-templates 10a and 10b. That is, in the case of pattern matching in 16 directions, pattern matching is performed on one pixel in 16 directions with the sub template 10a and 16 directions with the sub template 10b (double pattern matching is performed as usual). To detect.

  Note that the example illustrated in FIG. 8 is merely an example, and the embodiment is not limited thereto. In other words, any shape may be used as long as it has a detection range 11 at both ends in the longitudinal direction. Further, the detection range 11 may not be in contact with the end of the template 10. That is, it is only necessary that the independent detection ranges 11 are arranged on both ends in the longitudinal direction from the center of the template 10. Further, the number of detection ranges 11 is not limited to two, and three or more detection ranges 11 may be arranged on the template 10.

  In the first and second embodiments described above, the case of detecting a linear signal included in a two-dimensional image has been described. However, the embodiment is not limited to this, and may be a case where a linear signal included in the three-dimensional image data is detected. FIG. 9 is a diagram for explaining a modification according to the third embodiment. FIG. 9 shows the template 10 in the three-dimensional image data.

  For example, when detecting a linear signal included in the three-dimensional image data, the signal detection unit 152 according to the third embodiment has detection ranges 11 at both ends in the longitudinal direction, as shown in FIG. Then, a linear signal is detected using a square column template 10 having a hollow area 12 in the center. In such a case, the signal detection unit 152 performs pattern matching in a predetermined direction for each voxel.

  For example, the signal detection unit 152 detects the linear signals included in the three-dimensional space by sequentially executing pattern matching in 16 directions while gradually changing the angle of the template 10. It should be noted that the shape of the template used for the three-dimensional image data can take various shapes as in the case of the two-dimensional template.

  In the above-described embodiment, the case where the image processing apparatus 100 detects a linear signal has been described. However, the embodiment is not limited to this. For example, the medical image diagnostic apparatus 200 may detect a linear signal. That is, for example, the above-described image processing apparatus 100 may be incorporated in the medical image diagnostic apparatus 200. In other words, the control unit of the medical image diagnostic apparatus 200 may include the above-described data acquisition unit 151, signal detection unit 152, and display image generation unit 153, and execute the above-described processing.

  According to the image processing apparatus of at least one embodiment described above, it is possible to improve the accuracy of detection of a linear signal included in an image.

  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.

DESCRIPTION OF SYMBOLS 100 Image processing apparatus 110 Input part 120 Display part 150 Control part 151 Data acquisition part 152 Signal detection part 153 Display image generation part 200 Medical image diagnostic apparatus

Claims (6)

Image data acquisition means for acquiring medical image data including an image of a linear device ;
In each of a plurality of positions in the medical image data , a signal detection region including a detection range that is independent on both ends in the longitudinal direction is set in a plurality of directions, and when a signal is detected in each of the detection ranges, by signal included in the signal detecting region is judged to be a linear signal, a signal detecting means for detecting the linear signal included in the medical image data,
An image processing apparatus comprising: The image processing apparatus according to claim 1, wherein the detection range in the signal detection area is determined based on the number of pixels, the ratio, or the size of the signal detection area. The signal on the basis of the position of the detection range in the detection area, the image processing apparatus according to claim 1 or 2, further comprising a display image generating means for generating a display image. The image processing apparatus according to claim 3 , wherein the display image generation unit performs a smoothing process or an enhancement process on pixels within a detection range included in the signal detection area. The display image generation means, when a signal is detected in each of the detection ranges included in the signal detection region, executes enhancement processing for pixels in a range different from the detection range. Item 4. The image processing apparatus according to Item 3 . The medical image diagnostic apparatus characterized by comprising an image processing apparatus according to any one of claims 1-5.