Ultrasonic observation device, working method of ultrasonic observation device, and working procedure of ultrasonic observation device

Abstract

An ultrasonic observation device generates a plurality of ultrasonic images along a time series based on ultrasonic signals obtained by an ultrasonic transducer transmitting and receiving an observation object, and includes a processor configured to perform the following operations: for each ultrasonic image located before and after each other along the time series, calculate a correlation value using a block matching method for each of a plurality of regions set in each ultrasonic image, calculate a contrast that is a ratio of the correlation values ​​calculated for the plurality of regions, calculate a distribution of the contrast in each ultrasonic image, and select an ultrasonic image based on the contrast and the distribution of the contrast. Thus, an ultrasonic observation device with high accuracy in selecting an image useful for observation by a user is provided.

Description

Technical Field

[0001] The present invention relates to an ultrasonic observation device, a working method of the ultrasonic observation device and a working procedure of the ultrasonic observation device. Background Art

[0002] Conventionally, an ultrasonic observation device has been used in the medical field. The ultrasonic observation device generates an ultrasonic image as a scanned image of a cross section of a subject based on an ultrasonic signal obtained by transmitting and receiving an ultrasonic transducer disposed at the front end of an insertion portion for insertion into a subject. Among the ultrasonic observation devices, an ultrasonic observation device having a freeze function is known in which an image of a desired timing is displayed by a user while a display device displays the subject image in real time. In addition, an ultrasonic observation device having a pre-frame function is also known in which a subject image of a fixed period is always temporarily stored, and an image with less jitter caused by relative movement is selected from the temporarily stored images as a freeze image at the time when the user presses a freeze switch.

[0003] As a technique for selecting an image with little motion by a pre-frame function, there is known an ultrasonic observation apparatus that selects a freeze-frame image based on information on motion within an ultrasonic image (for example, see Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-131100 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, in the technology of Patent Document 1, there is a situation in which an image showing the influence of multiple reflections caused by a strong ultrasonic reflector (such as the housing of the ultrasonic transducer, air, etc.) existing in the subject is judged as an image with little movement, and an image useful for observation by a user such as a doctor is not selected. In addition, in the technology of Patent Document 1, an image useful for observation by a user such as an image containing a puncture needle cannot be selected.

[0009] The present invention has been made in view of the above, and an object of the present invention is to provide an ultrasonic observation device that can select an image useful for observation by a user with high accuracy, an operating method of the ultrasonic observation device, and an operating program of the ultrasonic observation device.

[0010] Solutions for solving problems

[0011] In order to solve the above-mentioned problems and achieve the purpose, an ultrasonic observation device involved in one embodiment of the present invention generates multiple ultrasonic images along a time series based on ultrasonic signals obtained by an ultrasonic vibrator transmitting and receiving an observation object. The ultrasonic observation device is characterized in that it includes a processor, and the processor is configured to perform the following actions: for each ultrasonic image located before and after along the time series, a correlation value is calculated using a block matching method for each of a plurality of regions set in each ultrasonic image, a contrast is calculated as a ratio of the correlation values ​​calculated for the plurality of regions, a distribution of the contrast in each ultrasonic image is calculated, and an ultrasonic image is selected based on the contrast and the distribution of the contrast.

[0012] In addition, in the ultrasonic observation apparatus according to one aspect of the present invention, the contrast is a ratio between a maximum value and a minimum value of the correlation value within a predetermined range including each region.

[0013] In an ultrasonic observation apparatus according to one aspect of the present invention, the processor is configured to detect a multiple reflection region based on the distribution of the contrast and select an ultrasonic image based on a size of the multiple reflection region.

[0014] In addition, the ultrasonic observation device involved in one embodiment of the present invention is characterized in that the processor is configured to detect an area formed by continuous areas with a contrast greater than a threshold centered on a transducer area as the multiple reflection area, and the transducer area is the ultrasonic transducer displayed in the ultrasonic image.

[0015] In addition, an ultrasonic observation device involved in one embodiment of the present invention is characterized in that the processor is configured to calculate the movement amount based on the correlation value, and is configured to select an ultrasonic image based on the contrast, the distribution of the contrast and the movement amount, wherein the movement amount is the amount of movement of the subject between ultrasonic images located before and after along the time series.

[0016] In the ultrasonic observation apparatus according to one aspect of the present invention, the processor is configured to select an ultrasonic image having a large contrast in a predetermined region within each ultrasonic image based on the distribution of the contrast.

[0017] In the ultrasonic observation apparatus according to one aspect of the present invention, the processor is configured to select an ultrasonic image based on the contrast and the distribution of the contrast when receiving an input of a freeze instruction signal.

[0018] In the ultrasonic observation apparatus according to one aspect of the present invention, the processor is configured to calculate a correlation value for each of a plurality of regions set in each ultrasonic image between the ultrasonic images located successively in time series.

[0019] In addition, regarding an operating method of an ultrasonic observation device involved in one embodiment of the present invention, the ultrasonic observation device generates a plurality of ultrasonic images along a time series by a processor based on an ultrasonic signal obtained by an ultrasonic vibrator transmitting and receiving an observation object, and the operating method of the ultrasonic observation device is characterized in that it includes the following steps: a correlation value calculation step of calculating a correlation value for each of a plurality of regions set in each ultrasonic image, using a block matching method, for each ultrasonic image located before and after along the time series; a contrast calculation step of calculating a contrast that is a ratio of the correlation values ​​calculated for the plurality of regions; a distribution calculation step of calculating a distribution of the contrast in each ultrasonic image; and an image selection step of selecting an ultrasonic image based on the contrast and the distribution of the contrast.

[0020] In addition, regarding an operation program of an ultrasonic observation device involved in one embodiment of the present invention, the ultrasonic observation device generates a plurality of ultrasonic images along a time series based on an ultrasonic signal obtained by an ultrasonic vibrator transmitting and receiving an observation object, the operation program of the ultrasonic observation device is characterized in that a processor of the ultrasonic observation device is caused to execute the following steps: a correlation value calculation step of calculating a correlation value using a block matching method for each of a plurality of regions set in each ultrasonic image, for each of ultrasonic images located before and after each other along the time series; a contrast calculation step of calculating a contrast that is a ratio of the correlation values ​​calculated for the plurality of regions; a distribution calculation step of calculating a distribution of the contrast in each ultrasonic image; and an image selection step of selecting an ultrasonic image based on the contrast and the distribution of the contrast.

[0021] Effects of the Invention

[0022] According to the present invention, it is possible to realize an ultrasonic observation device that can select an image useful for observation by a user with high accuracy, an operating method of the ultrasonic observation device, and an operating program of the ultrasonic observation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a block diagram showing the configuration of an ultrasonic diagnostic system including the ultrasonic observation apparatus according to the first embodiment of the present invention.

[0024] Figure 2 The diagram shows the measurement area (block) set in the image in order to calculate the correlation value.

[0025] Figure 3 It is a diagram showing a situation of calculating a correlation value.

[0026] Figure 4 : is a flowchart showing an outline of a process of selecting an ultrasonic image by the ultrasonic observation apparatus.

[0027] Figure 5 This is a diagram showing an example of blocks set in an ultrasonic image.

[0028] Figure 6 Yes means Figure 5 The diagram shown is a diagram of the distribution of correlation values ​​of block Bmn centered on the calculated position of the minimum correlation value.

[0029] Figure 7 Yes means Figure 5 The diagram shown is a diagram of the distribution of correlation values ​​of the block Bxy centered at the calculated position of the minimum correlation value.

[0030] Figure 8 Yes means Figure 2 A diagram of multiple reflection areas in an ultrasound image is shown.

[0031] Fig. 9 The figure shows an ultrasonic image including a puncture needle. DETAILED DESCRIPTION

[0032] The following is an explanation of the embodiments of the ultrasonic observation device, the working method of the ultrasonic observation device, and the working program of the ultrasonic observation device according to the present invention with reference to the accompanying drawings. In addition, the present invention is not limited to these embodiments. The present invention can be generally applied to the ultrasonic observation device, the working method of the ultrasonic observation device, and the working program of the ultrasonic observation device.

[0033] In addition, in the description of the drawings, the same or corresponding elements are appropriately marked with the same symbols. In addition, it should be noted that the drawings are schematic, and the relationship between the dimensions of the elements, the ratio of the elements, etc. are sometimes different from the actual. Sometimes, even between the drawings, there are parts where the relationship and ratio of the dimensions are different from each other.

[0034] (Implementation Method)

[0035] Figure 1 This is a block diagram showing the configuration of an ultrasonic diagnostic system including the ultrasonic observation apparatus according to the first embodiment of the present invention. Figure 1 The ultrasonic diagnostic system 1 shown includes: an ultrasonic endoscope 2 that transmits ultrasonic waves to a subject to be observed and receives ultrasonic waves reflected by the subject; an ultrasonic observation device 3 that generates an ultrasonic image based on the ultrasonic signal acquired by the ultrasonic endoscope 2; and a display device 4 that displays the ultrasonic image generated by the ultrasonic observation device 3.

[0036] The ultrasonic endoscope 2 has an ultrasonic transducer 21 at its front end, which converts the electrical pulse signal received from the ultrasonic observation device 3 into an ultrasonic pulse (sound pulse) and then irradiates the subject, and converts the ultrasonic echo reflected by the subject into an electrical echo signal represented by a voltage change for output. The ultrasonic transducer 21 is arranged at the front end of the insertion part for insertion into the subject. The ultrasonic transducer 21 is a radial type in which the scanning surface of the ultrasonic transducer 21 is arranged along the insertion direction of the insertion part of the endoscope, but it can also be a convex type or a linear type. In addition, the ultrasonic endoscope 2 can either cause the ultrasonic transducer 21 to scan mechanically, or a plurality of elements can be arranged in an array as the ultrasonic transducer 21, and the elements related to transmission and reception can be electronically switched or the transmission and reception of each element can be delayed to perform scanning electronically.

[0037] The ultrasonic endoscope 2 generally has an imaging optical system and an imaging element, and can be inserted into the digestive tract (esophagus, stomach, duodenum, large intestine) or respiratory organs (trachea, bronchi) of the subject to be examined to image the digestive tract, respiratory organs and their surrounding organs (pancreas, gallbladder, bile duct, bile duct, lymph nodes, mediastinal organs, blood vessels, etc.). In addition, the ultrasonic endoscope 2 has a light guide that guides the illumination light irradiated to the subject during imaging. The front end of the light guide reaches the front end of the insertion portion of the ultrasonic endoscope 2 inserted into the subject, and on the other hand, the base end of the light guide is connected to a light source device that generates illumination light.

[0038] The ultrasonic observation device 3 generates a plurality of ultrasonic images in time series based on ultrasonic signals transmitted and received by the ultrasonic transducer 21 to the observation object. The ultrasonic observation device 3 includes a transceiver 31 , a controller (processor) 32 , a frame memory 33 , an input unit 34 , and a storage unit 35 .

[0039] The transmitting and receiving unit 31 is electrically connected to the ultrasonic endoscope 2 , transmits a transmission signal (pulse signal) composed of a high voltage pulse based on a predetermined waveform and transmission timing to the ultrasonic transducer 21 , and receives an echo signal as an electrical reception signal from the ultrasonic transducer 21 .

[0040] The frequency band of the pulse signal transmitted by the transmitting and receiving unit 31 may be a wide frequency band that substantially covers the linear response band of the electroacoustic conversion of the pulse signal in the ultrasonic transducer 21 into an ultrasonic pulse.

[0041] The transmitting and receiving unit 31 also has a function of transmitting various control signals outputted from the control unit 32 to the ultrasonic endoscope 2 , and receiving various information including an ID for identification from the ultrasonic endoscope 2 and transmitting the various information to the control unit 32 .

[0042] The control unit (processor) 32 controls the entire ultrasonic diagnostic system 1. The control unit 32 is implemented using a CPU (Central Processing Unit) having calculation and control functions, various calculation circuits, etc. The control unit 32 reads information stored and saved in the storage unit 35 from the storage unit 35, and controls the ultrasonic observation device 3 in a unified manner by executing various calculation processes related to the working method of the ultrasonic observation device 3.

[0043] The control unit (processor) 32 includes an addition phase adjustment unit 32a, a signal processing unit 32b, a scan converter 32c, an image processing unit 32d, a block setting unit 32e, a correlation value calculation unit 32f, a movement amount calculation unit 32g, a contrast calculation unit 32h, a distribution calculation unit 32i, a multiple reflection detection unit 32j, and an image selection unit 32k. However, the control unit 32 and any one of the addition phase adjustment unit 32a to the image selection unit 32k may be configured using other CPUs or the like.

[0044] The phase addition unit 32a receives the echo signal from the transmitting and receiving unit 31 to generate and output digital high-frequency (RF: Radio Frequency) signal data (hereinafter referred to as RF data). The phase addition unit 32a performs STC (Sensitivity Time Control) correction to amplify the echo signal with a higher amplification factor as the receiving depth increases, performs filtering and other processing on the amplified echo signal, and then generates RF data in the time domain by performing A / D conversion, and outputs the RF data to the signal processing unit 32b. In addition, when the ultrasonic endoscope 2 has a structure in which the ultrasonic transducer 21 with a plurality of elements arranged in an array is electronically scanned, the phase addition unit 32a has a multi-channel circuit for beam synthesis corresponding to the plurality of elements.

[0045] The signal processing unit 32b generates digital B-mode reception data based on the RF data received from the addition phase unit 32a. The signal processing unit 32b performs known processing such as bandpass filtering, envelope detection, and logarithmic transformation on the RF data to generate digital B-mode reception data. In the logarithmic transformation, the common logarithm of the amount obtained by dividing the RF data by the reference voltage Vc is taken and expressed in decibels. The signal processing unit 32b outputs the generated B-mode reception data to the image processing unit 32d.

[0046] The scan converter 32c converts the scanning direction of the B-mode reception data received from the signal processing unit 32b to generate frame data. Specifically, the scan converter 32c converts the scanning direction of the B-mode reception data from the scanning direction of ultrasound to the display direction of the display device 4.

[0047] The image processing unit 32d generates B-mode image data (hereinafter, also simply referred to as image data) including an ultrasonic image which is a B-mode image obtained by converting the amplitude of an echo signal into brightness for display. The image processing unit 32d generates B-mode image data by performing signal processing using known techniques such as gain processing and contrast processing on the frame data from the scan converter 32c, and performing data thinning according to a data step size determined according to the display range of the image in the display device 4. The B-mode image is a grayscale image obtained by aligning the values ​​of variables, namely, R (red), G (green), and B (blue) when the RGB color system is used as the color space.

[0048] The image processing unit 32d performs coordinate transformation on the B-mode reception data from the signal processing unit 32b so as to rearrange the scanning range correctly in space, and then performs interpolation processing between the B-mode reception data to fill the gaps between the B-mode reception data to generate B-mode image data.

[0049] Figure 2 is a diagram showing the measurement area (block) set for the image in order to calculate the correlation value. Figure 2 As shown, the block setting unit 32e sets the ultrasonic image IM which is the latest ultrasonic image. n The blocks B11 to Bpq are set in a grid shape with a length of p and a width of q (p and q are natural numbers greater than or equal to 2). Figure 2 The approximate center of includes the transducer region T, which is the ultrasonic transducer 21 displayed in the ultrasonic image. In addition, the example using the radial type ultrasonic transducer 21 in which the transducer region T is located in the center of the ultrasonic image is described here, but the ultrasonic transducer 21 may also be a convex type or a linear type.

[0050] The correlation value calculation unit 32f calculates the correlation value for each of the plurality of regions set in each ultrasonic image, for each ultrasonic image located before and after (hereinafter, in the present embodiment, as an example, adjacent to each other in the time series) in the time series, using the block matching method. Specifically, the correlation value calculation unit 32f calculates the Sum of Absolute Difference (SAD) value of the pixel values, which is a type of correlation value, using the block matching method, for example.

[0051] Figure 3 It is a diagram showing a situation of calculating a correlation value. Figure 3 It means calculation Figure 2 The figure shows the movement amount of block Bmn. Figure 3 As shown, the correlation value calculation unit 32f follows Figure 3 The arrows shown will sequentially move the n-1Set, and the ultrasound image IM n A plurality of positions are set as the calculation positions of the correlation value, including the block Bmn' included in the search area SA set on the periphery of the block Bmn having the same position as the set block Bmn, and the correlation values ​​SAD indicating the similarity between the set block Bmn' and the block Bmn are calculated in sequence. In addition, here, SAD is used as the correlation value in the block matching method, but other correlation values ​​(such as SSD: Sum of Squared Difference) may also be used.

[0052] The movement amount calculation unit 32g calculates the movement amount of the subject between the ultrasonic images located before and after (adjacent to each other) in the time series based on the correlation value SAD. Specifically, the movement amount calculation unit 32g calculates the movement amount of the ultrasonic image IM of the latest frame among the plurality of ultrasonic images stored in the frame memory 33. n The movement amount is the amount by which the subject captured in the ultrasonic image of the previous frame moves relative to the subject captured in the ultrasonic image of the previous frame. When the correlation value calculation unit 32f calculates the correlation values ​​SAD of all blocks at the calculation positions included in the search area SA, the movement amount calculation unit 32g calculates the vector from the center of the block Bmn to the center of the block with the smallest correlation value SAD as the movement amount. Then, the movement amount calculation unit 32g repeatedly calculates the movement amount for each block, thereby calculating the ultrasonic image IM n Finally, the movement amount calculation unit 32g calculates the frame movement amount representing the movement of the entire image based on the statistical values ​​(average value, mode value, etc.) of the movement amounts of multiple blocks.

[0053] The contrast calculation unit 32h calculates the contrast related to the correlation value SAD for each block Bmn. Here, the contrast is assumed to be the ratio of the maximum value to the minimum value of the correlation value SAD within the specified range of the search area SA mentioned above (wherein, there are other definitions for contrast, and those definitions may also be used). Specifically, the contrast calculation unit 32h calculates the ratio of the maximum value to the minimum value of the correlation value SAD within a specified range centered on the calculation position where the correlation value SAD is the smallest in the search area SA (for example, within a range including calculation positions that are 5 calculation positions apart from each other in the top, bottom, left, and right directions) as the contrast. In addition, the contrast calculation unit 32h may also change the size of the specified range for calculating the contrast according to the range of the ultrasonic image. For example, when the range of the ultrasonic image is large (a large range is captured), the contrast calculation unit 32h sets the specified range to be small. This is because the pattern of multiple reflections described later becomes smaller when the range is large.

[0054] The distribution calculation unit 32i calculates the distribution of contrast in each ultrasonic image. Specifically, the distribution calculation unit 32i compares the contrast value of each block calculated by the contrast calculation unit 32h with the ultrasonic image IM nto associate with the position in .

[0055] The multiple reflection detection unit 32j detects the multiple reflection area based on the contrast distribution calculated by the distribution calculation unit 32i. The multiple reflection area refers to the area where the ultrasonic image appears due to the influence of a strong reflector such as the housing of the ultrasonic transducer 21. Figure 2 The multiple reflection detection unit 32j detects a region formed by a series of regions with a contrast greater than a threshold value centered on the transducer region T as a multiple reflection region. The threshold value is, for example, an average value of the contrast of the ultrasonic image, but may also be a statistical value such as a central value or a mode value, or may be a preset value or a user-set value.

[0056] The image selection unit 32k selects an ultrasonic image based on the contrast and the distribution of the contrast. Specifically, the image selection unit 32k selects an ultrasonic image based on the size of the multiple reflection area detected by the multiple reflection detection unit 32j. In addition, the image selection unit 32k may also select an ultrasonic image based on the contrast, the distribution of the contrast, and the amount of movement. When receiving the input of the freeze instruction signal, the image selection unit 32k selects an ultrasonic image based on the contrast and the distribution of the contrast.

[0057] The frame memory 33 is implemented by using, for example, a ring buffer, and stores a fixed amount (predetermined number of frames N) of ultrasonic images generated by the image processing unit 32d in a time series. When the capacity is insufficient (when the predetermined number of frames of B-mode image data are stored), the oldest B-mode image data is overwritten with the latest B-mode image data, thereby storing the latest ultrasonic images of the predetermined number of frames in the order of the time series. Figure 1 As shown in FIG. 1 , the frame memory 33 stores the latest ultrasonic image, that is, the ultrasonic image IM of the nth frame (n is a natural number greater than or equal to 2). n A plurality of ultrasonic images (IM n-1 ,IM n-2 ,IM n-3 , ...). Furthermore, the frame memory 33 stores the correlation value calculated by the correlation value calculator 32f, the movement amount calculated by the movement amount calculator 32g, the contrast calculated by the contrast calculator 32h, and the distribution of the contrast calculated by the distribution calculator 32i in association with the ultrasonic image.

[0058] The input unit 34 is implemented using a user interface such as a keyboard, a mouse, or a touch panel, and receives input of various information. The input unit 34 receives input of a freeze instruction signal, which is an instruction input for causing the display device 4 to display a freeze image by the freeze function.

[0059] The storage unit 35 stores various programs including a working program for executing the working method of the ultrasonic observation device 3. The working program can also be recorded in a computer-readable recording medium such as a hard disk, a flash memory, a CD-ROM, a DVD-ROM, a floppy disk, etc. and circulated widely. In addition, the various programs mentioned above can also be obtained by downloading via a communication network. The communication network mentioned here can be realized, for example, through an existing public line network, a LAN (Local Area Network), a WAN (Wide Area Network), etc., whether wired or wireless.

[0060] The storage unit 35 having the above configuration is realized by using a ROM (Read Only Memory) in which various programs are installed in advance, a RAM (Random Access Memory) for storing calculation parameters and data for each process, and the like.

[0061] Next, the process of selecting an ultrasonic image by the ultrasonic diagnostic system 1 will be described. Figure 4 FIG. 4 is a flowchart showing an overview of the process of selecting an ultrasonic image by an ultrasonic observation apparatus. Figure 4 As shown, the adder phase adjustment unit 32a, the signal processing unit 32b, the scan converter 32c, and the image processing unit 32d perform predetermined signal processing on the echo signal output by the ultrasonic endoscope 2 and received by the transmitting and receiving unit 31 to generate an ultrasonic image IM. n (Step S1).

[0062] Next, the block setting unit 32e sets the ultrasonic image IM n Grid-shaped blocks are set (step S2).

[0063] Then, the correlation value calculation unit 32f calculates the correlation value of the ultrasonic image IM n The correlation value SAD of each block is set (step S3).

[0064] Then, the movement amount calculation unit 32g calculates the movement amount between adjacent ultrasonic images based on the correlation value SAD (step S4).

[0065] Furthermore, the contrast calculation unit 32h calculates the contrast related to the correlation value SAD (step S5). Figure 5 FIG. 4 is a diagram showing an example of a block set in an ultrasonic image. Figure 5 The ultrasound image shown in IM n The contrast between the block Bmn and the block Bxy set in FIG.

[0066] The block Bmn is a region strongly affected by multiple reflections of white portions with high brightness and black portions with low brightness that are periodically continuous around the transducer region T. Figure 6 Yes means Figure 5 The diagram shown is a diagram of the distribution of correlation values ​​of block Bmn centered on the calculated position of the minimum correlation value. Figure 6 The correlation value SAD shown is a value that decreases as the regions are more similar. In block Bmn, due to the influence of multiple reflections, the correlation value increases rapidly as the distance from the calculation position of the minimum correlation value increases. As a result, in block Bmn, the contrast = maximum value A1 / minimum value A2 is large.

[0067] On the other hand, the block Bxy is a region that is not affected by multiple reflections. Figure 7 Yes means Figure 5 The distribution of correlation values ​​of the block Bxy shown is centered on the calculated position of the minimum correlation value. Figure 7 As shown, in block Bxy, the correlation value gradually increases as the distance from the calculated position of the minimum correlation value increases. As a result, in block Bxy, the contrast = maximum value A3 / minimum value A4 is small.

[0068] Then, the distribution calculation unit 32i calculates the ultrasonic image IM n The distribution of contrast within (step S6).

[0069] Then, the multiple reflection detection section 32 j detects the multiple reflection area based on the distribution of the contrast calculated by the distribution calculation section 32 i (step S7 ). Figure 8 Yes means Figure 2 Figure 2 shows a diagram of multiple reflection areas in an ultrasound image. Figure 8 As shown, the multiple reflection detection unit 32j detects the area B1 formed by the continuous areas with a contrast greater than a threshold value centered on the vibrator area T as a multiple reflection area. Specifically, the multiple reflection detection unit 32j detects the area B1 formed by the continuous areas with a contrast greater than a threshold value centered on the vibrator area T in four directions of up, down, left, and right as a multiple reflection area. On the other hand, the multiple reflection detection unit 32j does not detect the areas B21, B22, and B23 that are not continuous from the vibrator area T although the contrast is greater than the threshold value as multiple reflection areas. In addition, the multiple reflection detection unit 32j may also detect the areas B1 and B23 as areas formed by the continuous areas with a contrast greater than a threshold value centered on the vibrator area T in eight diagonal directions of up, down, left, and right as multiple reflection areas.

[0070] The control unit 32 determines whether a freeze instruction signal is input (step S8 ). Specifically, the control unit 32 determines whether a predetermined instruction for instructing a freeze is input from the input device to the input unit 34 .

[0071] When the control unit 32 determines that the freeze instruction signal has not been input (step S8: No), the process returns to step S1 and continues the process.

[0072] On the other hand, when the control unit 32 determines that the freeze instruction signal is input (step S8: "Yes"), the image selection unit 32k selects an ultrasonic image to be displayed as a freeze image on the display device 4 (step S9). Specifically, the image selection unit 32k selects an ultrasonic image in which the multiple reflection area calculated by the multiple reflection detection unit 32j is small and the movement amount calculated by the movement amount calculation unit 32g is small as the freeze image.

[0073] Then, the display device 4 displays a freeze-frame image based on the input from the ultrasonic observation device 3 (step S10 ).

[0074] As described above, according to the ultrasonic observation device 3, the image selection unit 32k selects an ultrasonic image with a small multiple reflection area, thereby preventing an ultrasonic image greatly affected by multiple reflections from being selected as a freeze-frame image. Therefore, the ultrasonic observation device 3 is an ultrasonic observation device with high accuracy in selecting images useful for the user's observation.

[0075] In addition, since the image selection unit 32 k selects an image with a small amount of movement, it is possible to prevent an image with a large amount of movement when the subject is photographed from being selected as a still image.

[0076] In addition, being located one after the other in time series means that the display order of two ultrasonic images set in time series among a plurality of ultrasonic images is very close to each other (for example, an order of being adjacent), and being adjacent in time series is not limited to, for example, ultrasonic images IM n With IM n-1 That is, directly adjacent in time series, including, for example, ultrasound images IM n With IM n-2 In the time series, as in the relationship of , one to a predetermined number of images are adjacent to each other (adjacent to each other at one interval, adjacent to each other at a predetermined interval).

[0077] (Variant 1)

[0078] The image selection unit 32k may select an ultrasonic image having a large contrast in a predetermined region in each ultrasonic image based on the contrast distribution. Specifically, the image selection unit 32k selects an ultrasonic image including a puncture needle based on the contrast and the contrast distribution.

[0079] Fig. 9 is a diagram showing an ultrasonic image including a puncture needle. Fig. 9As shown in FIG. 1 , when the ultrasonic endoscope 2 having the convex ultrasonic transducer 21 is used, the puncture needle N is projected into the ultrasonic image from the direction corresponding to the base end side of the insertion portion of the ultrasonic endoscope 2 toward the center of the ultrasonic image. The puncture needle N captured in the ultrasonic image is a region with high brightness. As a result, the edge of the puncture needle N captured in the ultrasonic image has a high contrast in relation to the correlation value SAD.

[0080] The image selection unit 32k selects an image with high contrast at a preset position on the upper right side of the ultrasonic image, that is, the proximal end side of the puncture needle N. As a result, the image selection unit 32k can select an image in which the puncture needle N is photographed, and the user can selectively browse the image in which the puncture needle N is photographed.

[0081] (Variant 2)

[0082] The image selection unit 32k may also select an ultrasonic image after excluding images of structures that obstruct observation, such as air, that are captured in a predetermined amount or more. The air captured in the ultrasonic image is an area with extremely low brightness. As a result, the edge of the air captured in the ultrasonic image has a large contrast with respect to the correlation value. For example, the image selection unit 32k may select an ultrasonic image after excluding an ultrasonic image in which an area with a large contrast is greater than a predetermined amount as an ultrasonic image in which a large amount of air is captured. In addition, the image selection unit 32k may exclude ultrasonic images in which air is captured, taking into account the position of the area with a large contrast.

[0083] Those skilled in the art can easily deduce further effects and variations. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the concept of the general invention defined by the claims and their equivalents.

[0084] Description of Reference Numerals

[0085] 1: ultrasonic diagnostic system; 2: ultrasonic endoscope; 3: ultrasonic observation device; 4: display device; 21: ultrasonic transducer; 31: transmitting and receiving unit; 32: control unit; 32a: addition phase adjustment unit; 32b: signal processing unit; 32c: scan converter; 32d: image processing unit; 32e: block setting unit; 32f: correlation value calculation unit; 32g: movement amount calculation unit; 32h: contrast calculation unit; 32i: distribution calculation unit; 32j: multiple reflection detection unit; 32k: image selection unit; 33: frame memory; 34: input unit; 35: storage unit.

Claims

1. An ultrasonic observation device that generates a plurality of ultrasonic images in a time series based on an ultrasonic transducer transmitting an ultrasonic wave to an observation object and receiving an ultrasonic signal obtained by the ultrasonic wave reflected by the observation object, wherein: A processor is provided, wherein the processor is configured to perform the following operations: For each ultrasonic image located before and after each other in the time series, a correlation value is calculated for each of a plurality of regions set in each ultrasonic image, wherein: The correlation value indicates the similarity between a pixel value of one of the plurality of calculation positions of the ultrasonic image located in the front, middle and back and a pixel value of a corresponding calculation position of the ultrasonic image located in the back, middle and back. calculating a contrast of the correlation values ​​calculated for the plurality of regions, wherein the contrast is a ratio of a maximum value to a minimum value of the correlation values ​​within a predetermined range including each region, calculating the spatial distribution of the contrast within each ultrasound image, An ultrasound image is selected based on the contrast and the spatial distribution of the contrast.

2. The ultrasonic observation device according to claim 1, characterized in that: The processor is configured to detect a multi-reflection region based on the distribution of the contrast, and select an ultrasonic image based on a size of the multi-reflection region.

3. The ultrasonic observation device according to claim 2, characterized in that: The processor is configured to detect, as the multiple reflection region, a region formed by a series of regions having a contrast greater than a threshold value and centered around a transducer region, the transducer region being the ultrasound transducer displayed in an ultrasound image.

4. The ultrasonic observation device according to claim 1, characterized in that: The processor is configured to calculate a movement amount based on the correlation value, and to select an ultrasonic image based on the contrast, a distribution of the contrast, and the movement amount, which is an amount of movement of the subject between ultrasonic images located before and after in a time series.

5. The ultrasonic observation device according to claim 1, characterized in that: The processor is configured to select an ultrasonic image having a large contrast in a predetermined region in each ultrasonic image based on the distribution of the contrast.

6. The ultrasonic observation device according to claim 1, characterized in that: The processor is configured to select an ultrasonic image based on the contrast and the distribution of the contrast when receiving an input of a freeze instruction signal.

7. The ultrasonic observation device according to claim 1, characterized in that: The processor is configured to calculate a correlation value for each of a plurality of regions set in each ultrasonic image, between the ultrasonic images located successively in time series.

8. The ultrasonic observation device according to claim 1, characterized in that: The ultrasonic image is selected in which, as the spatial distribution of the contrast, there is no region in which regions having the contrast greater than a threshold value continue to each other.

9. A method for operating an ultrasonic observation device, wherein the ultrasonic observation device generates a plurality of ultrasonic images along a time series by a processor based on an ultrasonic transducer transmitting an ultrasonic wave to an observation object and receiving an ultrasonic signal obtained by the ultrasonic wave reflected by the observation object, wherein the method for operating the ultrasonic observation device is characterized in that it comprises the following steps: a correlation value calculation step of calculating, for each of the plurality of regions set in each of the ultrasonic images located in the front and back along the time series, a correlation value, wherein the correlation value indicates a similarity between a pixel value of one of the plurality of calculation positions of the ultrasonic image located in the front among the front and back and a pixel value of a corresponding calculation position of the ultrasonic image located in the back among the front and back; a contrast calculation step of calculating a contrast of the correlation values ​​calculated for the plurality of regions, wherein the contrast is a ratio of a maximum value to a minimum value of the correlation values ​​within a prescribed range including each region; a distribution calculation step of calculating the spatial distribution of the contrast in each ultrasonic image; and The image selection step selects an ultrasonic image based on the contrast and the spatial distribution of the contrast.

10. A computer-readable recording medium having a working program of an ultrasonic observation device recorded thereon, wherein the ultrasonic observation device generates a plurality of ultrasonic images along a time series based on an ultrasonic transducer transmitting an ultrasonic wave to an observation object and receiving an ultrasonic signal obtained by the ultrasonic wave reflected by the observation object, wherein the working program of the ultrasonic observation device causes a processor of the ultrasonic observation device to execute the following steps: The correlation value calculation step is to calculate the correlation value for each of a plurality of regions set in each ultrasonic image, for each of the ultrasonic images located before and after each other in the time series, wherein: The correlation value indicates the similarity between a pixel value of one of the plurality of calculation positions of the ultrasonic image located in the front, middle and back and a pixel value of a corresponding calculation position of the ultrasonic image located in the back, middle and back; a contrast calculation step of calculating a contrast of the correlation values ​​calculated for the plurality of regions, wherein the contrast is a ratio of a maximum value to a minimum value of the correlation values ​​within a prescribed range including each region; a distribution calculation step, calculating the spatial distribution of the contrast in each ultrasonic image; as well as The image selection step selects an ultrasonic image based on the contrast and the spatial distribution of the contrast.

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