Image processing apparatus and control method of image processing apparatus

Abstract

The image processing apparatus (1) includes: an accuracy calculating section (13) that analyzes an ultrasonic image of a subject by frame and calculates accuracy of a blood vessel in the ultrasonic image; a blood vessel detecting section (16) that detects a blood vessel whose accuracy calculated by the accuracy calculating section (13) is higher than an accuracy threshold value; and an accuracy threshold value changing section (15) that changes the accuracy threshold value in accordance with a plurality of accuracies calculated by the accuracy calculating section (13) with respect to a plurality of ultrasonic images.

Description

Technical Field

[0001] The present invention relates to an image processing device for detecting blood vessels in an ultrasonic image and a method for controlling the image processing device. Background Art

[0002] Conventionally, ultrasound images of the subject have been observed to identify the blood vessels within the ultrasound image, for example, in preparation for inserting a puncture needle into a blood vessel. It is known that physicians and other examiners typically require a certain level of expertise to accurately identify the location of blood vessels by observing ultrasound images. Therefore, to facilitate the examination of blood vessels within ultrasound images, a device has been developed that detects blood vessels within ultrasound images by analyzing ultrasound images, as disclosed in Patent Document 1.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2012 / 147505 Summary of the Invention

[0006] Technical issues to be solved by the invention

[0007] For example, if the subject has high body fat, the overall brightness of the ultrasound image increases, potentially causing artifacts to appear within blood vessels. Furthermore, if gas is trapped within the subject, the boundary between blood vessels and surrounding tissue in the ultrasound image may become blurred. Thus, the way blood vessels are observed in ultrasound images varies depending on the subject. Therefore, even using the technology disclosed in Patent Document 1, it is still impossible to accurately detect blood vessels in ultrasound images in some subjects.

[0008] An object of the present invention is to provide an image processing device and a method for controlling the image processing device that can detect blood vessels in an ultrasonic image with high accuracy.

[0009] Means for solving technical problems

[0010] The image processing device according to the present invention is characterized by comprising: an accuracy calculation unit that analyzes an ultrasonic image of a subject frame by frame and calculates the accuracy of blood vessels in the ultrasonic image; a blood vessel detection unit that detects blood vessels whose accuracy calculated by the accuracy calculation unit is higher than an accuracy threshold; and an accuracy threshold change unit that changes the accuracy threshold based on multiple accuracies calculated by the accuracy calculation unit for multiple frames of ultrasonic images.

[0011] The image processing device may include an ultrasonic probe and an image generating unit that generates an ultrasonic image analyzed by the accuracy calculating unit based on transmission and reception of an ultrasonic beam using the ultrasonic probe.

[0012] Furthermore, the image processing device may include an accuracy memory for storing the accuracy calculated by the accuracy calculation unit.

[0013] Furthermore, the image processing device can include a device control unit that controls storage of the accuracy in the accuracy memory.

[0014] The device control unit can determine whether the ultrasonic probe is stationary, and when it is determined that the ultrasonic probe has been stationary for a predetermined time or longer, the accuracy is stored in the accuracy memory.

[0015] Furthermore, the device control unit can determine whether the ultrasonic probe is in contact with the body surface of the subject, and store the accuracy in the accuracy memory when it is determined that the ultrasonic probe is in contact with the body surface of the subject.

[0016] Furthermore, when the device control unit determines that the moving speed of the ultrasonic probe is lower than a predetermined moving speed, the device control unit can store the accuracy in the accuracy memory.

[0017] Furthermore, the device control unit can store the accuracy calculated based on the ultrasonic image of the frame selected at the frame interval corresponding to the moving speed of the ultrasonic probe from among the plurality of ultrasonic image frames generated by the image generating unit in the accuracy memory.

[0018] The accuracy threshold value changing unit may calculate a change value by multiplying the highest value of a plurality of accuracy values ​​calculated for a plurality of frames of ultrasonic images by a predetermined ratio, and may change the accuracy threshold value to the change value.

[0019] Furthermore, the accuracy threshold changing unit may calculate a change value by statistically analyzing a plurality of accuracies calculated for a plurality of frames of ultrasonic images, and change the accuracy threshold to the change value.

[0020] Preferably, the accuracy threshold changing unit changes the accuracy threshold to the changed value when the changed value is lower than the accuracy threshold of the blood vessel detection unit.

[0021] The image processing apparatus may include a change notification unit that notifies a user of a change in the accuracy threshold.

[0022] Furthermore, the image processing apparatus may include an accuracy threshold memory for storing the accuracy threshold changed by the accuracy threshold changing unit for each subject.

[0023] Furthermore, the image processing apparatus may include an input device for a user to perform input operations, and a manual changing unit that changes the accuracy threshold value in accordance with the input operations performed via the input device.

[0024] The control method of the image processing device involved in the present invention is characterized by including the following steps: analyzing an ultrasonic image of a subject frame by frame to calculate the accuracy of blood vessels in the ultrasonic image, detecting blood vessels whose accuracy exceeds an accuracy threshold, and changing the accuracy threshold based on multiple accuracies calculated for multiple frames of ultrasonic images.

[0025] Effects of the Invention

[0026] According to the present invention, the image processing device includes: an accuracy calculation unit that analyzes multiple frames of ultrasonic images of a subject on a frame-by-frame basis to calculate the accuracy of blood vessels within the ultrasonic images; a blood vessel detection unit that detects blood vessels whose accuracy calculated by the accuracy calculation unit is higher than an accuracy threshold; and an accuracy threshold changing unit that changes the accuracy threshold based on the multiple accuracies calculated by the accuracy calculation unit, thereby enabling high-precision detection of blood vessels within the ultrasonic images. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a block diagram showing the configuration of an image processing device according to the first embodiment of the present invention.

[0028] Figure 2 FIG. 1 is a diagram showing an example of an ultrasonic image including blood vessels.

[0029] Figure 3 This is a diagram showing an example of a seek bar (SeekBar) displayed on a display in the first embodiment of the present invention.

[0030] Figure 4 This is a diagram showing an example of a dialog box in the first embodiment of the present invention.

[0031] Figure 5 It is a diagram showing another example of the dialog box in the first embodiment of the present invention.

[0032] Figure 6 This is a flowchart showing the operation of the image processing device according to the first embodiment of the present invention.

[0033] Figure 7 This is a block diagram showing the configuration of an ultrasonic diagnostic apparatus according to a second embodiment of the present invention.

[0034] Figure 8 This is a block diagram showing the configuration of a transmission and reception circuit in a second embodiment of the present invention.

[0035] Figure 9 This is a block diagram showing the configuration of an image generating unit in the second embodiment of the present invention.

[0036] Figure 10 This is a flowchart showing the operation of the ultrasonic diagnostic apparatus according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0038] The following description of the constituent elements is based on representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0039] In addition, in this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0040] In this specification, “same” and “identical” include an error range generally allowed in the technical field.

[0041] First embodiment

[0042] Figure 1 The configuration of an image processing apparatus 1 according to a first embodiment of the present invention is shown. The image processing apparatus 1 receives an ultrasonic image from an external device (not shown) such as an ultrasonic diagnostic apparatus, and displays and analyzes the ultrasonic image.

[0043] The image processing device 1 includes a display control unit 11, to which a display 12 is connected. Furthermore, the image processing device 1 includes an accuracy calculation unit 13, to which an accuracy memory 14 is connected, and to which an accuracy threshold value changing unit 15 is connected. Furthermore, the accuracy threshold value changing unit 15 is connected to a blood vessel detection unit 16, an accuracy threshold value memory 17, and a change notification unit 19. The accuracy threshold value memory 17 is connected to the blood vessel detection unit 16. Furthermore, the image processing device 1 includes a manual change unit 18, which is connected to the blood vessel detection unit 16 and the change notification unit 19. Furthermore, the blood vessel detection unit 16 and the change notification unit 19 are connected to the display control unit 11.

[0044] Furthermore, a device control unit 20 is connected to the display control unit 11, the accuracy calculation unit 13, the accuracy memory 14, the accuracy threshold value change unit 15, the blood vessel detection unit 16, the accuracy threshold value memory 17, the manual change unit 18, and the change notification unit 19. Furthermore, an input device 21 is connected to the device control unit 20.

[0045] The display control unit 11 , the accuracy calculation unit 13 , the accuracy threshold change unit 15 , the blood vessel detection unit 16 , the manual change unit 18 , the change notification unit 19 , and the device control unit 20 constitute a processor 22 .

[0046] Furthermore, an ultrasonic image is inputted to the display control unit 11 and the accuracy calculation unit 13 from an external device (not shown) such as an ultrasonic diagnostic apparatus.

[0047] The accuracy calculation unit 13 analyzes the ultrasound image of the subject frame by frame and calculates the accuracy of the blood vessels within the ultrasound image. The accuracy of the blood vessels within the ultrasound image is an indicator that indicates the likelihood of a blood vessel-like structure contained in the ultrasound image, for example, expressed by the probability that the structure is a blood vessel. The accuracy calculation unit 13 calculates the accuracy for each blood vessel-like structure within the ultrasound image. The blood vessels for which the accuracy calculation is performed include veins and arteries.

[0048] The accuracy calculation unit 13 can calculate the accuracy of blood vessels by applying, for example, a simple template matching method, a machine learning method described in Csurka et al.: Visual Categorization with Bags of Keypoints, Proc. of ECCV Workshop on Statistical Learning in Computer Vision, pp. 59-74 (2004), or a general image recognition method using deep learning described in Krizhevsk et al.: ImageNet Classification with Deep Convolutional Neural Networks, Advances in Neural Information Processing Systems 25, pp. 1106-1114 (2012) to the ultrasonic image.

[0049] Figure 2 An example of an ultrasonic image U including blood vessel-like structures A1, A2, and A3 is shown. When calculating the accuracy of the ultrasonic image U, the accuracy calculation unit 13 calculates the accuracy for each of the structures A1, A2, and A3.

[0050] The accuracy memory 14 is a memory for storing the accuracy calculated by the accuracy calculation unit 13. The accuracy stored in the accuracy memory 14 is sent to the accuracy threshold value changing unit 15 under the control of the device control unit 20.

[0051] Furthermore, as the accuracy memory 14, for example, a flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), FD (Flexible Disc), MO (Magneto-Optical Disc), MT (Magnetic Tape), RAM (Random Access Memory), CD (Compact Disc), DVD (Digital Versatile Disc), SD card (Secure Digital card), USB memory (Universal Serial Bus memory) and other recording media can be used.

[0052] The blood vessel detection unit 16 has an accuracy threshold value for the accuracy of the blood vessels and detects blood vessels whose accuracy calculated by the accuracy calculation unit 13 is higher than the accuracy threshold value. When the accuracy calculated by the accuracy calculation unit 13 is lower than the accuracy threshold value, the blood vessel detection unit 16 does not detect the blood vessels with the accuracy. For example, Figure 2 Among the three structures A1, A2, and A3 shown, when the accuracy for structures A1 and A2 is greater than the accuracy threshold and the accuracy for structure A3 is less than the accuracy threshold, structures A1 and A2 are detected as blood vessels, while structure A3 is not detected as a blood vessel.

[0053] Thus, the accuracy threshold determines the ease of blood vessel detection. That is, the higher the accuracy threshold, the less likely structures A1, A2, and A3 are to be detected as blood vessels, while the lower the accuracy threshold, the easier it is for structures A1, A2, and A3 to be detected as blood vessels.

[0054] The accuracy threshold changer 15 calculates an accuracy change value for each of the structures A1 , A2 , and A3 based on the multiple accuracies calculated by the accuracy calculator 13 for the multiple frames of ultrasonic images U, and changes the accuracy threshold of the blood vessel detector 16 to the changed value.

[0055] The accuracy threshold changing unit 15 can calculate the change value by, for example, multiplying the highest value of a plurality of accuracy values ​​calculated for a plurality of frames of ultrasonic images U by a predetermined ratio smaller than 1.0, such as 0.8.

[0056] In this case, the accuracy threshold value changing unit 15 preferably excludes accuracy values ​​having values ​​corresponding to so-called outliers. For example, the accuracy threshold value changing unit 15 calculates the average value and standard deviation of a plurality of accuracy values ​​and excludes accuracy values ​​having values ​​equal to or greater than the sum of the average value and three times the calculated standard deviation from the plurality of accuracy values. This can eliminate accuracy values ​​corresponding to outliers.

[0057] Furthermore, the accuracy threshold changing unit 15 can also calculate the change value by performing a statistical analysis on the multiple accuracy values ​​calculated for the multiple frames of ultrasonic images U. Performing a statistical analysis on the multiple accuracy values ​​means analyzing the distribution of the multiple accuracy values. For example, the accuracy threshold changing unit 15 can sort the multiple accuracy values ​​in ascending or descending order, set the highest accuracy value as the first position, and calculate the change value using the accuracy values ​​that are in a predetermined order, such as the top 20%, relative to the total number of the multiple accuracy values. Furthermore, the accuracy threshold changing unit 15 can sort the multiple accuracy values ​​in ascending or descending order, set the highest accuracy value as the first position, and calculate the change value using the accuracy values ​​that are in a predetermined order relative to the total number of the multiple accuracy values.

[0058] Furthermore, as an example of statistically analyzing a plurality of accuracy levels, the accuracy threshold value changing unit 15 can also calculate, as the change value, a sum of a constant times the standard deviation of the plurality of accuracy levels and an average value of the plurality of accuracy levels.

[0059] The accuracy threshold memory 17 is a memory that stores the accuracy threshold values ​​changed by the accuracy threshold changing unit 15, classified by subject. The accuracy threshold values ​​stored in the accuracy threshold memory 17 are transmitted to the blood vessel detection unit 16, for example, under the control of the device control unit 20, at the start of an examination of a subject corresponding to the accuracy threshold value, and are used as the initial value of the accuracy threshold value of the blood vessel detection unit 16.

[0060] As the accuracy threshold memory 17 , for example, a recording medium such as a flash memory, HDD, SSD, FD, MO optical disc, MT, RAM, CD, DVD, SD card, or USB memory can be used.

[0061] The input device 21 is a device used by a user to perform input operations and is composed of devices such as a keyboard, a mouse, a trackball, a touch pad, and a touch panel.

[0062] The manual change unit 18 changes the accuracy threshold to a specified value according to the input operation performed by the user via the input device 21. Examples of the input operation performed by the user via the input device 21 include: Figure 3The input operation using the drag bar B is shown. The drag bar B has a slide button B1 that slides between its two ends, and an accuracy threshold corresponding to the position of the slide button B1 can be specified. For example, in order to make it easy for the user to intuitively understand the meaning of the accuracy threshold, the specified range of accuracy can be made to correspond to the range of detection ease of 0 to 100, and the left end of the drag bar B can be displayed as "Detection Ease 0" and the right end as "Detection Ease 100" on the display 12. In this case, the closer the slide button B1 is to "Detection Ease 0" at the left end of the drag bar B, the lower the accuracy threshold can be specified, and the closer the slide button B1 is to "Detection Ease 100" at the right end of the drag bar B, the higher the accuracy threshold can be specified.

[0063] The change notification unit 19 notifies the user of the change in the accuracy threshold value.

[0064] For example, Figure 4 As shown, when the accuracy threshold is to be changed, the change notification unit 19 can display a dialog box P1 on the display 12 for selecting whether to execute or cancel the change of the accuracy threshold. The dialog box P1 includes a message "Do you want to change the detectability of the blood vessel?", the values ​​of the detectability before and after the change, an execute button C1 for executing the change of the accuracy threshold, and a cancel button C2 for canceling the change of the accuracy threshold.

[0065] Furthermore, when the accuracy threshold is changed, the change notification unit 19 can further classify the ease of detecting blood vessels into multiple levels such as "very difficult to detect", "difficult to detect", "average", "easy to detect", and "very easy to detect", and display the classification level instead of the values ​​of the ease of detecting before and after the change in the dialog box P1. Figure 5 In the dialog box P2 shown, “Easy to detect” is displayed as the detection ease before the change, and “Normal” is displayed as the detection ease after the change.

[0066] The device control unit 20 controls each unit of the image processing device 1 according to a pre-recorded program or the like.

[0067] Under the control of the device control unit 20 , the display control unit 11 performs predetermined processing on the ultrasonic image U and the structures A1 and A2 detected as blood vessels by the blood vessel detection unit 16 , and displays the resulting images on the display 12 .

[0068] The display 12 performs various displays under the control of the display control unit 11. The display 12 includes, for example, a display device such as an LCD (Liquid Crystal Display) or an organic EL display (Organic Electroluminescence Display).

[0069] The processor 22, which includes the display control unit 11, the accuracy calculation unit 13, the accuracy threshold change unit 15, the blood vessel detection unit 16, the manual change unit 18, the change notification unit 19, and the device control unit 20, is composed of a CPU (Central Processing Unit) and a control program for causing the CPU to perform various processes. However, the processor 22 may be composed of an FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), or another IC (Integrated Circuit), or a combination thereof.

[0070] Furthermore, the display control unit 11, accuracy calculation unit 13, accuracy threshold change unit 15, blood vessel detection unit 16, manual change unit 18, change notification unit 19, and device control unit 20 of the processor 22 may be partially or entirely integrated into a single CPU.

[0071] Next, use Figure 6 The flowchart shown in FIG. 1 illustrates the operation of the image processing apparatus 1 according to the first embodiment of the present invention. It is assumed that multiple frames of ultrasonic images U capturing the same part of the same subject are input to the image processing apparatus 1 from an external device such as an ultrasonic diagnostic apparatus (not shown).

[0072] First, in step S1, the device control unit 20 receives a command to start a series of processes for detecting blood vessels (the processes of steps S2 to S6). For example, when a user issues a command to start a series of processes for detecting blood vessels through an input operation on the input device 21, the device control unit 20 receives this command.

[0073] Next, in step S2, the accuracy calculation unit 13 calculates the accuracy of blood vessels for each ultrasonic image U input from an external device such as an ultrasonic diagnostic apparatus. Figure 2 As shown, when the ultrasonic image U includes three blood vessel-like structures A1, A2, and A3, the accuracy is calculated for each ultrasonic image U for each of the three structures A1, A2, and A3.

[0074] The plurality of accuracies calculated in this manner are stored in the accuracy memory 14 .

[0075] In the subsequent step S3, the accuracy threshold changing unit 15 calculates a change value for the accuracy threshold of the blood vessel detection unit 16 for each of the structures A1 to A3 within the ultrasonic image U, based on the multiple accuracy levels calculated in step S2 and stored in the accuracy memory 14. The accuracy threshold changing unit 15 calculates the change value by, for example, multiplying the highest value of the multiple accuracy levels calculated for multiple frames of ultrasonic image U by a predetermined ratio such as 0.8.

[0076] For example, if an ultrasound image of a subject with high body fat is known to have high overall brightness, the blood vessels in the ultrasound image may contain artifacts. Furthermore, if gas is trapped within the subject, the boundaries between the blood vessels and surrounding tissues in the ultrasound image may be blurred. Therefore, when calculating the accuracy of blood vessels in an ultrasound image where the blood vessels are difficult to see, the calculated accuracy may be lower than the accuracy calculated for an ultrasound image where the blood vessels are clearly visible.

[0077] The change value calculated by the accuracy threshold change unit 15 has a value lower than the highest value of multiple accuracy values ​​calculated for multiple frames of ultrasonic images U of the same subject. Therefore, even if the structures A1 to A3 in the ultrasonic image U become difficult to see due to the state of the subject, the structures A1 to A3 can be easily detected as blood vessels.

[0078] In step S4 , the accuracy threshold changing unit 15 changes the accuracy threshold of the blood vessel detecting unit 16 to the changed value calculated in step S3 .

[0079] When the accuracy threshold changing unit 15 wants to change the accuracy threshold of the blood vessel detecting unit 16, the change notification unit 19 can notify the user of the change of the accuracy threshold. Figure 4 As shown, the change notification unit 19 can display a dialog box P1 on the display 12, allowing the user to select whether to execute or cancel the change in the accuracy threshold. At this time, if the user selects the execute button C1 via the input device 21, the accuracy threshold change unit 15 changes the accuracy threshold of the blood vessel detection unit 16 to the changed value calculated in step S3. If the user selects the cancel button C2, the change in the accuracy threshold by the accuracy threshold change unit 15 is canceled.

[0080] By notifying the user of the change in the accuracy threshold in this manner, the user can clearly understand the change in the ease of detecting a blood vessel.

[0081] Furthermore, in step S4, in addition to the change of the accuracy threshold by the accuracy threshold change unit 15, the accuracy threshold can also be changed by the manual change unit 18. Figure 3As shown, the user specifies the accuracy threshold by sliding the slide button B1 of the drag bar B via the input device 21 , and the manual changing unit 18 changes the accuracy threshold to the value specified by the user.

[0082] By changing the accuracy threshold value in accordance with the input operation performed via the input device 21 in this manner, the ease of detecting blood vessels can be adjusted in more detail.

[0083] The accuracy threshold value changed in step S4 is stored for each subject in the accuracy threshold value memory 17. The stored accuracy threshold value is read under the control of the device control unit 20, for example, at the start of the next examination of the same subject, and can be used as the initial value of the accuracy threshold value of the blood vessel detection unit 16.

[0084] In step S5, the blood vessel detection unit 16 detects blood vessels with a higher accuracy than the accuracy threshold value changed in step S4. Figure 2 When the calculated accuracy for structures A1 and A2 shown is higher than the accuracy threshold and the calculated accuracy for structure A3 is lower than the accuracy threshold, structures A1 and A2 are detected as blood vessels, while structure A3 is not detected as a blood vessel.

[0085] Finally, in step S6, the blood vessel detection unit 16 displays the structures A1 and A2 detected as blood vessels in step S5 in an enhanced manner on the display 12. Although not shown, the blood vessel detection unit 16 can, for example, display the outlines of the structures A1 and A2 detected as blood vessels superimposed on the ultrasound image U on the display 12. Furthermore, for example, the structures A1 and A2 can be enhanced by giving them a color different from their surroundings. This allows the user to easily understand that the structures A1 and A2 are blood vessels.

[0086] As can be seen from the above description, according to the image processing device 1 involved in the first embodiment of the present invention, the accuracy threshold is changed according to the multiple accuracies calculated by the accuracy calculation unit 13 for the multiple frames of ultrasonic images U. Therefore, even if the blood vessels in the ultrasonic image U are difficult to see clearly due to the condition of the subject, the blood vessels can still be detected with high accuracy.

[0087] Furthermore, in step S4 , the accuracy threshold changing unit 15 preferably does not change the accuracy threshold when the change value calculated in step S3 is equal to or greater than the initial value of the accuracy threshold of the blood vessel detecting unit 16 , to prevent blood vessels from becoming difficult to detect.

[0088] Furthermore, if the accuracy threshold is significantly lower than a typical value, the likelihood of false blood vessel detection increases. Conversely, if the accuracy threshold is significantly higher than a typical value, blood vessels may not be detected. Therefore, it is preferable to set upper and lower limits for the accuracy threshold. For example, 0.8 times the initial value of the accuracy threshold can be set as the lower limit, and 1.2 times the initial value can be set as the upper limit. As a more specific example, if the initial value of the accuracy threshold is set to 0.75, the lower limit can be set to 0.60, and the upper limit can be set to 0.90.

[0089] Furthermore, while the change notification unit 19 has been described as notifying the user of a change in the accuracy threshold when the accuracy threshold changing unit 15 intends to change the accuracy threshold, it is also possible to notify the user that the accuracy threshold has been changed. This allows the user to clearly understand the accuracy threshold change and smoothly identify blood vessels.

[0090] Second embodiment

[0091] The image processing apparatus 1 of the first embodiment receives ultrasonic images U from an external device (not shown), but this method is not particularly limited. For example, the image processing apparatus 1 may be an ultrasonic diagnostic apparatus equipped with an ultrasonic probe and capable of analyzing ultrasonic images U captured by the ultrasonic probe.

[0092] Figure 7 The configuration of an ultrasonic diagnostic apparatus 1A according to the second embodiment is shown.

[0093] The ultrasonic diagnostic apparatus 1A includes an ultrasonic probe 2 and a diagnostic apparatus main body 3 , and the ultrasonic probe 2 and the diagnostic apparatus main body 3 are connected to each other.

[0094] The ultrasonic probe 2 includes a transducer array 31 , and a transceiver circuit 32 is connected to the transducer array 31 .

[0095] The diagnostic device main body 3 is configured as follows: An image generation unit 33 is added to the image processing device 1 of the first embodiment, and the device control unit 20 is replaced with a device control unit 20A. The processor 22 is replaced with a processor 22A including the image generation unit 33. The image generation unit 33 is connected to the transceiver circuit 32. Furthermore, the display control unit 11 and the accuracy calculation unit 13 are connected to the image generation unit 33. Compared to the device control unit 20 of the first embodiment, the device control unit 20A is further connected to the transceiver circuit 32 and the image generation unit 33.

[0096] The transducer array 31 of the ultrasonic probe 2 includes multiple transducers arranged in a one-dimensional or two-dimensional array. These transducers transmit ultrasonic waves in response to a drive signal supplied by the transceiver circuit 32, and receive ultrasonic echoes from the subject, outputting signals based on the ultrasonic echoes. Each transducer is constructed by forming electrodes at both ends of a piezoelectric material, such as a piezoelectric ceramic represented by PZT (Lead Zirconate Titanate), a polymer piezoelectric element represented by PVDF (Poly Vinylidene Di Fluoride), or a piezoelectric single crystal represented by PMN-PT (Lead Magnesium Niobate-Lead Titanate solid solution).

[0097] The transceiver circuit 32 transmits ultrasonic waves from the transducer array 31 under the control of the device control unit 20A and generates an acoustic ray signal based on the received signal obtained by the transducer array 31. Figure 8 As shown, the transmission and reception circuit 32 includes a pulse generator 41 connected to the transducer array 31 , and an amplifier 42 , an AD (Analog Digital) converter 43 , and a beamformer 44 connected in series in this order from the transducer array 31 .

[0098] The pulse generator 41, for example, includes multiple pulse generators and supplies drive signals to the multiple transducers by adjusting the delay amount according to a transmission delay pattern selected based on a control signal from the device control unit 20A, so that the ultrasonic waves emitted from the multiple transducers in the transducer array 31 form an ultrasonic beam. In this manner, when a pulsed or continuous-wave voltage is applied to the electrodes of the transducers in the transducer array 31, the piezoelectric body expands and contracts, generating pulsed or continuous-wave ultrasonic waves from each transducer. The combined wave of these ultrasonic waves forms an ultrasonic beam.

[0099] The transmitted ultrasonic beam is reflected by an object, such as a part of a subject, and propagates toward the transducer array 31 of the ultrasonic probe 2. The ultrasonic echoes thus propagated toward the transducer array 31 are received by each transducer constituting the transducer array 31. At this time, each transducer constituting the transducer array 31 expands and contracts upon receiving the propagated ultrasonic echoes, generating received signals as electrical signals, and outputting these received signals to the amplifier 42.

[0100] The amplifier 42 amplifies the signals input from each transducer constituting the transducer array 31 and transmits the amplified signals to the AD converter 43. The AD converter 43 converts the signals transmitted from the amplifier 42 into digital received data and transmits this received data to the beamformer 44. The beamformer 44 performs so-called receive focusing processing by adding together the received data converted by the AD converter 43 and applying delays to each data point according to the speed of sound or its distribution. This speed of sound or its distribution is set according to a receive delay pattern selected by a control signal from the device control unit 20A. This receive focusing processing generates a sound line signal obtained by adding together the received data points converted by the AD converter 43 in phase, with the focus of the ultrasonic echo narrowed. This sound line signal is transmitted to the image generator 33.

[0101] like Figure 9 As shown, the image generating section 33 has a structure in which a signal processing section 45 , a DSC (Digital Scan Converter) 46 , and an image processing section 47 are sequentially connected in series.

[0102] The signal processing unit 45 corrects the attenuation caused by distance on the acoustic ray signal transmitted by the transmitting and receiving circuit 32 according to the depth of the ultrasonic reflection position, and then performs envelope detection processing to generate a B-mode image signal which is tomographic image information related to the tissue in the subject.

[0103] The DSC 46 converts (raster converts) the B-mode image signal generated by the signal processing unit 45 into an image signal conforming to a scanning method of a general television signal.

[0104] Image processing unit 47 performs various necessary image processing, such as grayscale processing, on the B-mode image signal input from DSC 46, and then transmits the B-mode image signal to display control unit 11 and accuracy calculation unit 13 in accordance with instructions from device control unit 20. The B-mode image signal processed by image processing unit 47 is simply referred to as ultrasonic image U.

[0105] Next, use Figure 10 The flowchart shown in FIG. 1A is used to explain the operation of the ultrasonic diagnostic apparatus 1A according to the second embodiment. Steps S14 and S16 to S19 in the flowchart are respectively Figure 6 Steps S2 and S3 to S6 of the flowchart in the first embodiment shown are the same.

[0106] First, in step S11 , the user brings the ultrasonic probe 2 into contact with the body surface of the subject to capture an ultrasonic image U, thereby capturing an image of the blood vessels of the subject to be examined.

[0107] At this time, under the control of the device control unit 20A, the transceiver circuit 32 performs receive focusing processing using a preset sound velocity value to generate an acoustic line signal. The acoustic line signal generated by the transceiver circuit 32 is transmitted to the image generator 33. The image generator 33 generates an ultrasonic image U using the acoustic line signal transmitted from the transceiver circuit 32. The generated ultrasonic image U is transmitted to the display control unit 11 and displayed on the display 12.

[0108] In step S12, the device control unit 20A determines whether it has received a command to start a series of processes for blood vessel detection (the processes of steps S13 to S19). If, for example, the user has not input a command to start a series of processes for blood vessel detection through input operation on the input device 21, the device control unit 20A determines that the command has not been received and returns to step S11. If a new ultrasonic image U is generated in step S11, the process proceeds to step S12. Thus, while it is determined that the command to start a series of processes for blood vessel detection has not been received, steps S11 and S12 are repeated.

[0109] The user confirms the ultrasonic image U generated sequentially by repeating step S11 and step S12, for example, Figure 2 As shown, upon recognizing that an ultrasonic image U including the blood vessel-like structures A1 to A3 of the subject being examined has been obtained, a command to start a series of processes for detecting blood vessels is input via the input device 21. Thus, when the command to start a series of processes is input, the device control unit 20A determines in step S12 that the command to start a series of processes has been received, and the process proceeds to step S13.

[0110] In step S13 , an ultrasonic image U is generated in the same manner as in step S11 .

[0111] In step S14 , the accuracy calculator 13 analyzes the ultrasonic image U generated in step S13 and calculates the accuracy of the structures A1 to A3 in the ultrasonic image U. The blood vessel accuracy calculated for the structures A1 to A3 is stored in the accuracy memory 14 under the control of the device controller 20A.

[0112] In step S15, the device control unit 20A determines whether the number of frames of ultrasonic images U for which the vascular accuracy has been calculated in step S14 is N. N is an integer greater than or equal to 2, and for example, 20 to 100 is set as N. At the current time, only one frame of ultrasonic images U has been calculated for which the vascular accuracy has been calculated in step S14. Therefore, the device control unit 20A determines that the number of frames of ultrasonic images U for which the vascular accuracy has been calculated in step S14 is not N, and the process returns to step S13. Steps S13 to S15 are repeated in this manner until the number of frames of ultrasonic images U for which the vascular accuracy has been calculated in step S14 reaches N, and the calculated accuracy is sequentially stored in the accuracy memory 14.

[0113] In step S15 , if it is determined that the number of frames of the ultrasonic image U for which the accuracy of the blood vessel has been calculated in step S14 is N, the process proceeds to step S16 .

[0114] In step S16 , the accuracy threshold changing unit 15 calculates a change value for the accuracy threshold of the blood vessel detecting unit 16 based on a plurality of accuracy levels calculated for the N frames of ultrasonic images U by repeating steps S13 to S15 .

[0115] In step S17 , the accuracy threshold changing unit 15 changes the initial value of the accuracy threshold of the blood vessel detecting unit 16 to a changed value.

[0116] In step S18, the blood vessel detection unit 16 detects blood vessels with an accuracy higher than the accuracy threshold changed in step S17 for the latest ultrasonic image U that is generated last when steps S13 to S15 are repeated. Figure 2 Among the blood vessel-like structures A1 to A3 shown, when the accuracy of structures A1 and A2 exceeds the accuracy threshold and the accuracy of structure A3 falls below the accuracy threshold, the blood vessel detection unit 16 detects structures A1 and A2 as blood vessels.

[0117] Finally, in step S19 , the blood vessel detection unit 16 displays the structures A1 and A2 detected as blood vessels in step S18 on the latest ultrasonic image U in an enhanced manner on the display 12 .

[0118] As can be seen from the above description, the ultrasonic diagnostic apparatus 1A according to the second embodiment of the present invention changes the accuracy threshold value based on the multiple accuracies calculated by the accuracy calculation unit 13 for N frames of ultrasonic images U. Therefore, even if the blood vessels in the ultrasonic image U are difficult to see clearly due to the condition of the subject, the blood vessels can still be detected with high accuracy, similar to the image processing apparatus 1 according to the first embodiment.

[0119] In addition, if Figure 7As shown, the transceiver circuit 32 is provided in the ultrasonic probe 2 , but may be provided in the diagnostic apparatus main body 3 instead of the ultrasonic probe 2 .

[0120] Furthermore, the image generating unit 33 is provided in the diagnostic apparatus main body 3 , but may be provided in the ultrasonic probe 2 instead of the diagnostic apparatus main body 3 .

[0121] And, as Figure 9 As shown, the image generator 33 includes a signal processor 45 , a DSC 46 , and an image processor 47 . The signal processor 45 may also be included in the ultrasonic probe 2 .

[0122] Furthermore, the connection method between the ultrasonic probe 2 and the diagnostic apparatus main body 3 is not particularly limited, and may be a wired connection or a wireless connection.

[0123] Furthermore, the diagnostic device body 3 may be a so-called handheld type that is easy for the user to carry, or a so-called fixed type.

[0124] Furthermore, in step S12, when the user inputs a command to start a series of processes for detecting blood vessels via the input device 21, the device control unit 20A determines that the command has been received. However, the trigger for determining that the command to start a series of processes for detecting blood vessels has been received is not specifically limited to inputting a command via the input device 21.

[0125] For example, the device control unit 20A can determine whether the ultrasonic probe 2 is in contact with the subject's body surface, and when it is determined that the ultrasonic probe 2 is in contact with the subject's body surface, determine that a command to start a series of processes for detecting blood vessels has been received.

[0126] Regarding the determination of whether the ultrasonic probe 2 is in contact with the surface of the subject, for example, a pressure sensor (not shown) for measuring the contact pressure of the ultrasonic probe 2 on the surface of the subject is installed on the ultrasonic probe 2. When the pressure value measured by the pressure sensor exceeds a specified pressure threshold, the device control unit 20A can determine that the ultrasonic probe 2 is in contact with the surface of the subject, and when the measured pressure value is below the specified pressure threshold, it can determine that the ultrasonic probe 2 has left the surface of the subject.

[0127] Furthermore, it is known that when the ultrasonic probe 2 is in contact with the surface of the subject, it captures an ultrasonic image U corresponding to the tissue within the subject, having a brightness exceeding a certain level. However, when the ultrasonic probe 2 is removed from the surface of the subject, in a so-called airborne state, the ultrasonic echoes do not propagate to the transducer array 31, resulting in the capture of an entirely black ultrasonic image U. Therefore, the device control unit 20A determines that the ultrasonic probe 2 is in contact with the surface of the subject when an ultrasonic image U having a brightness exceeding a certain level is captured, and determines that the ultrasonic probe 2 is removed from the surface of the subject when an entirely black ultrasonic image U is captured.

[0128] Furthermore, for example, the device control unit 20A can also determine that a command to start a series of processes for detecting blood vessels has been received when imaging of the ultrasonic image U is started.

[0129] By determining that a command to start a series of processes for detecting a blood vessel has been received using these methods, the user can save time and effort in performing input operations via the input device 21 and can more smoothly execute the series of processes for detecting a blood vessel.

[0130] The processes of steps S13 to S15 are repeated until the accuracy of blood vessels is calculated for a predetermined number of N frames of ultrasonic images U. However, the processes of steps S13 to S15 may be repeated from the time the process of the first step S13 is started until a predetermined time has passed. In this case, in step S15, the device control unit 20A determines whether the predetermined time has passed since the start of the first step S13. The predetermined time can be set, for example, to 1 to 5 seconds.

[0131] Furthermore, the predetermined number of frames of the ultrasonic image U used for the determination in step S15 and the time elapsed from the initial step S13 can be set in advance by the user via the input device 21 .

[0132] Each user of the ultrasonic diagnostic apparatus 1A can set these frame numbers and elapsed time values, which are then stored in the apparatus control unit 20A. For example, at the start of an examination of a subject, the user using the ultrasonic diagnostic apparatus 1A is authenticated, and the stored frame number or elapsed time corresponding to the authenticated user can be read and used in the determination of step S15.

[0133] As examples of user authentication, there are a method of inputting an identification code corresponding to the user from the input device 21, a method of providing a fingerprint sensor (not shown) in the ultrasonic diagnostic device 1A to identify the user's fingerprint, a method of providing a camera (not shown) in the ultrasonic diagnostic device 1A and identifying the user's face photographed by the camera, a method of photographing the user's eyes with a camera to identify the user's iris, a method of providing a microphone (not shown) in the ultrasonic diagnostic device 1A and identifying the voiceprint based on the user's voice recorded by the microphone, a method of reading a barcode (one-dimensional code) corresponding to the user, a method of reading a two-dimensional code such as a QR (Quick Response) code (registered trademark) corresponding to the user, and the like.

[0134] Furthermore, in step S14 , the device control unit 20A stores the accuracy in the accuracy memory 14 every time the accuracy calculation unit 13 calculates the accuracy. However, the timing of storing the accuracy is not particularly limited thereto.

[0135] Typically, when an ultrasonic image U containing a blood vessel is captured, the ultrasonic probe 2 is mostly stationary. Therefore, for example, it is also possible to determine whether the ultrasonic probe 2 is stationary, and when it is determined that the ultrasonic probe 2 has been stationary for more than a specified time, the calculated accuracy is saved in the accuracy memory 14.

[0136] For example, motion sensors such as acceleration sensors and gyro sensors and pressure sensors for detecting the motion of the ultrasonic probe 2 are installed, and the device control unit 20A can determine whether the ultrasonic probe 2 is stationary based on the values ​​measured by these sensors.

[0137] Furthermore, when the ultrasonic probe 2 is stationary, similar ultrasonic images U are often captured continuously. Therefore, the device control unit 20A can, for example, calculate the similarity of all ultrasonic images U continuously generated by the image generation unit 33, and determine that the ultrasonic probe 2 is stationary when the calculated similarity is above a predetermined similarity threshold.

[0138] Furthermore, when the ultrasonic probe 2 has left the surface of the subject, the accuracy of the blood vessels cannot be calculated. Therefore, the device control unit 20A can determine whether the ultrasonic probe 2 is in contact with the surface of the subject by, for example, analyzing the ultrasonic image U or using the measured value of the pressure sensor installed on the ultrasonic probe 2, and save the accuracy when it is determined that the ultrasonic probe 2 is in contact with the surface of the subject, and stop saving the accuracy when it is determined that the ultrasonic probe 2 has left the surface of the subject.

[0139] Furthermore, when the user is unable to image the subject's blood vessels, the ultrasonic probe 2's movement speed is often high, while when the user is able to image the subject's blood vessels, the ultrasonic probe 2's movement speed is often low. Therefore, the device control unit 20A can determine whether the ultrasonic probe 2's movement speed is below a predetermined speed, and preserve accuracy if it is determined that the ultrasonic probe 2's movement speed is below the predetermined speed.

[0140] The moving speed of the ultrasonic probe 2 can be measured, for example, by an acceleration sensor (not shown) attached to the ultrasonic probe 2. In this case, the device control unit 20A can determine whether the moving speed measured by the sensor attached to the ultrasonic probe 2 is lower than a predetermined moving speed.

[0141] Furthermore, it is assumed that when the moving speed of the ultrasonic probe 2 is low, the similarity between the ultrasonic images U successively generated by the image generator 33 is greater, and when the moving speed of the ultrasonic probe 2 is high, the similarity between the ultrasonic images U successively generated is smaller. Therefore, the device control unit 20A calculates the similarity between frames successively generated by the image generator 33, for example, and can determine that the greater the calculated similarity, the higher the moving speed of the ultrasonic probe 2, and the smaller the calculated similarity, the lower the moving speed of the ultrasonic probe 2. Therefore, the device control unit 20A estimates the moving speed of the ultrasonic probe 2 based on the similarity between the ultrasonic images U successively generated by the image generator 33, and can also determine whether the estimated moving speed is lower than a predetermined moving speed.

[0142] Furthermore, the moving speed of the ultrasonic probe 2 is often higher when the user cannot photograph the blood vessels of the examination object, and is often lower when the user can photograph the blood vessels of the examination object. Therefore, in order to improve the accuracy of the change value calculated by the accuracy threshold change unit 15, it is preferably set that the lower the moving speed of the ultrasonic probe 2, the greater the number of saved accuracies, and the higher the moving speed of the ultrasonic probe 2, the fewer the number of saved accuracies.

[0143] Therefore, the device control unit 20A can, for example, store the accuracy corresponding to the ultrasonic image U selected at a longer frame interval in the accuracy memory 14 when the moving speed of the ultrasonic probe 2 is higher, and store the accuracy corresponding to the ultrasonic image U selected at a shorter frame interval in the accuracy memory 14 when the moving speed of the ultrasonic probe 2 is lower. In this way, the device control unit 20A can store the accuracy calculated based on the ultrasonic image U of the frame selected at the frame interval corresponding to the moving speed of the ultrasonic probe 2 among the multiple frames of ultrasonic image U generated by the image generator 33 in the accuracy memory 14.

[0144] And, in Figure 10The flowchart shown shows a method in which the accuracy threshold is changed only once. However, if ultrasonic images U are continuously generated after the accuracy threshold is changed, a change value can be calculated each time the accuracy for N frames of ultrasonic images U is calculated, and the accuracy threshold of the blood vessel detection unit 16 can be changed to the change value. In this case, the accuracy threshold can be sequentially changed to a change value with higher accuracy.

[0145] Furthermore, if ultrasound images U continue to be generated after the accuracy threshold is changed, the accuracy threshold can be changed a predetermined number of times, such as one to five times, after which the accuracy threshold change can cease. If a blood vessel in ultrasound image U cannot be detected for some reason, it can be difficult to determine whether the cause is the ultrasound image U or the change in the accuracy threshold. Therefore, by specifying the number of times the accuracy threshold can be changed, even if blood vessels in ultrasound image U cannot be detected, the user can easily determine the cause and take appropriate measures.

[0146] Furthermore, the changed accuracy threshold can be reset to its initial value. For example, the accuracy threshold changing unit 15 can reset the accuracy threshold by the user inputting a reset command via input device 21. Furthermore, if the accuracy threshold has been changed multiple times, the accuracy threshold can be reset to the accuracy threshold before the most recent change, rather than to the initial value of the accuracy threshold, so as to perform a reset process by changing to the previous accuracy threshold for a predetermined number of changes. By resetting the accuracy threshold in this manner, for example, even if the accuracy threshold deviates from an appropriate value for some reason, the accuracy threshold changing unit 15 can still change the accuracy threshold back to an appropriate value.

[0147] Explanation of symbols

[0148] 1-Image processing device, 1A-Ultrasonic diagnostic device, 2-Ultrasonic probe, 3-Diagnostic device body, 11-Display control unit, 12-Display, 13-Accuracy calculation unit, 14-Accuracy memory, 15-Accuracy threshold change unit, 16-Vascular detection unit, 17-Accuracy threshold memory, 18-Manual change unit, 19-Change notification unit, 20, 20A-Device control unit, 21-Input device, 22, 22A-Processor, 31-Vibrator array, 32-Transmitting and receiving circuit, 33-Image generation unit, 41-Pulse generator, 42-Amplifier, 43-AD conversion unit, 44-Beamformer, 45-Signal processing unit, 46-DSC, 47-Image processing unit, A1-A3-Structures, B-Drag bar, B1-Slide button, C1-Execute button, C2-Cancel button, P1, P2-Dialog box, U-Ultrasonic image.

Claims

1. An image processing device comprising: an accuracy calculation unit that analyzes an ultrasonic image of a subject frame by frame and calculates the accuracy of a blood vessel-like structure in the ultrasonic image; a blood vessel detecting unit configured to detect the blood vessel-like structure for which the accuracy calculated by the accuracy calculating unit is higher than an accuracy threshold; and The accuracy threshold value changing unit changes the accuracy threshold value based on the plurality of accuracy values ​​calculated by the accuracy calculating unit for the plurality of frames of the ultrasonic image.

2. The image processing device according to claim 1, comprising: Ultrasound probe; and An image generating unit generates the ultrasonic image analyzed by the accuracy calculating unit based on transmission and reception of ultrasonic beams using the ultrasonic probe.

3. The image processing device according to claim 2, comprising: An accuracy memory stores the accuracy calculated by the accuracy calculation unit.

4. The image processing device according to claim 3, comprising: A device control unit controls storage of the accuracy in the accuracy memory.

5. The image processing apparatus according to claim 4, wherein: The device control unit determines whether the ultrasonic probe is stationary, and when it is determined that the ultrasonic probe has been stationary for a predetermined time or longer, stores the accuracy in the accuracy memory. The image processing apparatus according to claim 4 , wherein: The device control unit determines whether the ultrasonic probe is in contact with the body surface of the subject, and stores the accuracy in the accuracy memory when it is determined that the ultrasonic probe is in contact with the body surface of the subject.

7. The image processing apparatus according to claim 4, wherein: The device control unit stores the accuracy in the accuracy memory when determining that the moving speed of the ultrasonic probe is lower than a predetermined moving speed.

8. The image processing apparatus according to claim 4, wherein: The device control unit stores the accuracy calculated based on the ultrasonic image of the following frames, which are selected at a frame interval corresponding to the moving speed of the ultrasonic probe from among the multiple frames of ultrasonic images generated by the image generating unit, in the accuracy memory.

9. The image processing apparatus according to any one of claims 1 to 8, wherein: The accuracy threshold value changing unit calculates a change value by multiplying the highest value of the plurality of accuracy values ​​calculated for the plurality of frames of ultrasonic images by a predetermined ratio, and changes the accuracy threshold value to the change value.

10. The image processing apparatus according to any one of claims 1 to 8, wherein: The accuracy threshold changing unit calculates a change value by statistically analyzing the plurality of accuracies calculated for the plurality of frames of ultrasonic images, and changes the accuracy threshold to the change value.

11. The image processing apparatus according to claim 9, wherein: The accuracy threshold changing unit changes the accuracy threshold to the changed value when the changed value is lower than the accuracy threshold of the blood vessel detecting unit.

12. The image processing device according to any one of claims 1 to 8, comprising: A change notification unit notifies a user of the change in the accuracy threshold.

13. The image processing device according to any one of claims 1 to 8, comprising: The accuracy threshold memory stores the accuracy threshold changed by the accuracy threshold changing unit for each subject.

14. The image processing device according to any one of claims 1 to 8, comprising: An input device for a user to perform input operations; and A manual changing unit changes the accuracy threshold value according to an input operation performed via the input device.

15. A method for controlling an image processing device, comprising the following steps: analyzing a plurality of ultrasonic images of the subject frame by frame to calculate the accuracy of the blood vessel-like structure in the ultrasonic image; detecting the blood vessel-like structure with the accuracy being higher than an accuracy threshold; and The accuracy threshold is changed according to the plurality of accuracies.

Images