JP2013017713A - Ultrasonic image diagnostic apparatus and ultrasonic image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic image diagnostic apparatus and an ultrasonic image processing method, allowing acquisition of an ultrasonic image allowing accurate ultrasonic image diagnosis wherein a speckle is considered.SOLUTION: This ultrasonic image diagnostic apparatus 20 includes: an ultrasonic probe 20b outputting a transmission ultrasonic wave to a subject, and receiving a reflection ultrasonic wave from the subject to acquire a reception signal; an image generation part 204 converting the reception signal acquired by the ultrasonic probe 20b into a luminance signal, and generating ultrasonic image data from the luminance signal; a speckle detection part detecting a signal level of the speckle from the reception signal acquired by the ultrasonic probe 20b; and an adjustment part adjusting a conversion condition that the image generation part 204 converts the reception signal into the luminance signal on the basis of the signal level of the speckle detected by the speckle detection part.

Description

  The present invention relates to an ultrasonic diagnostic imaging apparatus and an ultrasonic image processing method.

  Conventionally, it has a vibration probe (probe) provided with a large number of transducers arranged, and transmits / receives ultrasonic waves to / from a subject such as a living body, and a signal obtained from the received ultrasonic waves 2. Description of the Related Art There has been known an ultrasonic diagnostic imaging apparatus that generates ultrasonic image data based on (reception signal) and displays an ultrasonic image on an image display apparatus based on the generated data. In such an ultrasonic diagnostic imaging apparatus, gain and dynamic range adjustment, gamma correction, and the like are performed on the log-amplified received signal, thereby optimizing the contrast of the ultrasonic image and improving visibility. Can be.

  Since the adjustment as described above is a very complicated operation in an ultrasonic diagnostic imaging apparatus having a wide range of parameters that need to be adjusted, in conventional ultrasonic diagnostic imaging apparatuses, for example, white noise and maximum luminance value from a histogram. Is detected, and the dynamic range is automatically adjusted to reduce the adjustment burden (see, for example, Patent Document 1).

  There is also a technique in which a histogram curve is obtained and gain or contrast is automatically adjusted based on the histogram curve (see, for example, Patent Documents 2 and 3).

  In addition, there is a technique in which an image is divided into a plurality of partial areas, a representative value of each partial area is extracted, and gain adjustment is automatically performed based on comparison with a threshold value (for example, see Patent Document 4).

  Also, there is a technique in which a received signal for one frame is divided into a plurality of depth regions, and the gain is adjusted for each depth region based on the difference between the overall average luminance level and the luminance level for each depth region. (For example, refer to Patent Document 5).

JP 2008-264530 A JP 2005-152422 A Japanese Patent Laid-Open No. 06-105850 Japanese Patent Application Laid-Open No. 07-236637 Japanese Patent Laid-Open No. 06-54849

By the way, speckle may appear on the ultrasonic image. Speckle is generated by interference between reflected waves and scattered waves generated from small tissue properties below the spatial resolution, and is different from noise having no regularity.
This speckle does not have living body boundary information but has living tissue information, and is useful for identifying the properties (hardness, etc.) of the liver and thyroid gland. Specifically, for example, speckle is considered when making a diagnosis of fatty liver.

  In this way, speckles are useful information in ultrasonic diagnostic imaging, but in the conventional technology described above, various parameters are automatically adjusted without taking speckles into account. In some cases, diagnosis was not possible.

  Accordingly, an object of the present invention is to provide an ultrasonic image diagnostic apparatus and an ultrasonic image processing method capable of acquiring an ultrasonic image, which enables accurate ultrasonic image diagnosis in consideration of speckle. .

In order to solve the above problems, the invention according to claim 1 is an ultrasonic diagnostic imaging apparatus.
An ultrasonic probe that outputs a transmission ultrasonic wave to the subject and receives a reflected ultrasonic wave from the subject to obtain a reception signal;
An image generation unit that converts a reception signal acquired by the ultrasonic probe into a luminance signal and generates ultrasonic image data from the luminance signal;
A speckle detection unit for detecting a signal level of speckles from a reception signal acquired by the ultrasonic probe;
The image generation unit includes an adjustment unit that adjusts a conversion condition for converting the received signal into a luminance signal based on the signal level of the speckle detected by the speckle detection unit.

According to a second aspect of the present invention, in the ultrasonic diagnostic imaging apparatus according to the first aspect,
The adjustment unit receives the speckle signal level detected by the speckle detection unit and the signal level of the received signal based on the reflected ultrasonic wave from the reflector inside the subject. The conversion condition for converting the signal into a luminance signal is adjusted.

The invention according to claim 3 is the ultrasonic diagnostic imaging apparatus according to claim 1 or 2,
Further equipped with an operation unit that can be operated by the user,
The speckle detection unit specifies a speckle region in accordance with an operation by the operation unit, and detects a signal level of the speckle from the specified speckle region.

The invention according to claim 4 is the ultrasonic diagnostic imaging apparatus according to any one of claims 1 to 3,
The adjustment unit specifies a maximum value and a minimum value of a speckle signal level detected from a reception signal acquired by the ultrasonic probe, and specifies a maximum value and a minimum value of a signal level of the specified speckle. The image generation unit adjusts the conversion condition for converting the received signal into the luminance signal so that the luminance difference between the luminance values of the luminance signal obtained by converting the luminance signal becomes larger.

According to a fifth aspect of the present invention, in the ultrasonic diagnostic imaging apparatus according to any one of the first to third aspects,
The adjustment unit specifies a maximum value and a minimum value of a speckle signal level detected from a reception signal acquired by the ultrasonic probe, and specifies a maximum value and a minimum value of a signal level of the specified speckle. The image generation unit adjusts the conversion condition for converting the received signal into the luminance signal so that each luminance value of the luminance signal obtained by converting the luminance signal is included in the intermediate luminance value.

The invention according to claim 6 is the ultrasonic diagnostic imaging apparatus according to claim 1,
The adjustment unit is configured so that the luminance difference between luminance values of luminance signals obtained by converting the signal levels of speckles detected from received signals at different depths inside the subject is reduced. The conversion condition for converting the received signal into the luminance signal is adjusted for each depth.

The invention according to claim 7 is an ultrasonic image processing method,
An ultrasonic transmission / reception step of outputting a transmission ultrasonic wave to the subject and acquiring a reception signal by receiving a reflected ultrasonic wave from the subject; and
Speckle input process for inputting speckle signal level;
A condition adjusting step for adjusting a conversion condition for converting a received signal into a luminance signal based on the signal level of the input speckle;
An image generation step of converting the received signal acquired in the ultrasonic transmission / reception step into a luminance signal based on the adjusted conversion condition and generating ultrasonic image data from the luminance signal, To do.

  According to the present invention, it is possible to acquire an ultrasonic image that enables accurate ultrasonic image diagnosis in consideration of speckle.

It is a block diagram which shows the functional structure of an ultrasonic image diagnostic apparatus. It is a block diagram which shows the functional structure of an image generation part. It is a figure which shows the luminance distribution of a reference ultrasonic image. It is a figure which shows the input-output characteristic of a gamma adjustment part. It is a figure which shows the input / output characteristic of a gain adjustment part. It is a figure which shows the input / output characteristic of a dynamic range adjustment part. It is a flowchart explaining a brightness adjustment control process.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  The ultrasonic diagnostic imaging apparatus 20 is an apparatus that displays and outputs the state of the internal tissue of a patient (subject) as an ultrasonic image. That is, the ultrasonic diagnostic imaging apparatus 20 transmits ultrasonic waves (transmission ultrasonic waves) to the inside of a subject such as a living body, and also reflects reflected waves (reflected ultrasonic waves: echoes) reflected within the subject. Receive. The ultrasonic diagnostic imaging apparatus 20 converts the received reflected wave into an electrical signal, and generates ultrasonic image data based on this. The ultrasonic diagnostic imaging apparatus 20 displays the internal state in the subject as an ultrasonic image based on the generated ultrasonic image data. Further, the ultrasonic diagnostic imaging apparatus 20 generates auxiliary information regarding the generated ultrasonic image data based on the imaging order information, and adds the auxiliary information to the ultrasonic image data to generate an image file having a predetermined standard. It is possible to generate.

  As shown in FIG. 1, the ultrasonic diagnostic imaging apparatus 20 includes an ultrasonic diagnostic imaging apparatus main body 20a and an ultrasonic probe 20b. The ultrasonic probe 20b transmits ultrasonic waves as described above and receives reflected waves. The ultrasonic diagnostic imaging apparatus main body 20a is connected to the ultrasonic probe 20b via the cable 20c, and transmits an electric signal drive signal to the ultrasonic probe 20b, thereby transmitting to the ultrasonic probe 20b. Send ultrasonic waves. Further, the ultrasonic diagnostic imaging apparatus main body 20a receives a reception signal that is an electrical signal generated by the ultrasonic probe 20b in response to the reflected ultrasonic wave from within the subject received by the ultrasonic probe 20b. Then, ultrasonic image data is generated as described above.

  The ultrasonic probe 20b includes transducers (not shown) made of piezoelectric elements, and a plurality of the transducers are arranged in a one-dimensional array in the azimuth direction (scanning direction), for example. In the present embodiment, for example, an ultrasonic probe 20b including 192 transducers is used. The vibrators may be arranged in a two-dimensional array. Further, the number of vibrators can be arbitrarily set. In this embodiment, a linear electronic scan probe is used for the ultrasonic probe 20b. However, any of an electronic scanning method or a mechanical scanning method may be used, and a linear scanning method or a sector scanning method may be used. Alternatively, any method of the convex scanning method can be adopted.

  The ultrasonic diagnostic imaging apparatus main body 20a includes, for example, an operation input unit (operation unit) 201, a transmission unit 202, a reception unit 203, an image generation unit 204, a memory unit 205, a DSC (Digital Scan Converter) 206, and the like. The display unit 207 and the control unit 208 are provided.

The operation input unit 201 includes, for example, various switches, buttons, a trackball, a mouse, a keyboard, and the like for inputting data such as a command to start diagnosis and personal information of a subject, and the like. The data is output to the control unit 208.
Specifically, when the user inputs a predetermined operation using the operation input unit 201, the speckle detection unit 303 specifies the speckle region as described later.

  The transmission unit 202 is a circuit that supplies a drive signal, which is an electrical signal, to the ultrasonic probe 20b via the cable 20c and generates transmission ultrasonic waves in the ultrasonic probe 20b under the control of the control unit 208. . The transmission unit 202 includes, for example, a clock generation circuit, a delay circuit, and a pulse generation circuit. The clock generation circuit is a circuit that generates a clock signal that determines the transmission timing and transmission frequency of the drive signal. The delay circuit sets a delay time for each individual path corresponding to each transducer corresponding to the transmission timing of the drive signal, delays the transmission of the drive signal by the set delay time, and transmits the transmission beam constituted by the transmission ultrasonic waves. This is a circuit for focusing. The pulse generation circuit is a circuit for generating a pulse signal as a drive signal at a predetermined cycle. The transmission unit 202 configured as described above drives, for example, a continuous part (for example, 64) of a plurality (for example, 192) of transducers arranged in the ultrasound probe 20b. To generate transmission ultrasonic waves. The transmission unit 202 performs scanning (scanning) by shifting the vibrator to be driven in the azimuth direction every time transmission ultrasonic waves are generated.

  The receiving unit 203 is a circuit that receives a reception signal that is an electrical signal from the ultrasound probe 20b via the cable 20c under the control of the control unit 208. The receiving unit 203 includes, for example, an amplifier, an A / D conversion circuit, and a phasing addition circuit. The amplifier is a circuit for amplifying a received signal with a preset amplification factor for each individual path corresponding to each transducer. The A / D conversion circuit is a circuit for A / D converting the amplified received signal. A phasing addition circuit is a circuit for adjusting a time phase by giving a delay time to each individual path corresponding to each transducer with respect to an A / D converted reception signal, and adding these (phasing addition) It is.

  The image generation unit 204 performs envelope detection processing, logarithmic amplification, and the like on the reception signal acquired from the reception unit 203, adjusts gamma, gain, and dynamic range to perform luminance conversion, so that the signal intensity is luminance. Ultrasonic image data (B-mode image data) of a luminance signal expressed by brightness is generated. As shown in FIG. 2, the image generation unit 204 includes an envelope detection processing unit 301, a logarithmic amplification processing unit 302, a speckle detection unit 303, an adjustment unit 304, a luminance conversion unit 305, and the like.

  The envelope detection processing unit 301 obtains a reception signal from the reception unit 203, performs envelope detection processing on the reception signal, and the logarithmic amplification processing unit 302 performs processing on the reception signal after the envelope detection processing. A logarithmic amplification process is performed to amplify the signal intensity logarithmically.

The speckle detection unit 303 acquires the reception signal subjected to the logarithmic amplification processing by the logarithmic amplification processing unit 302, and detects the signal level of the speckle from the reception signal. Here, the speckle signal level is a signal intensity range of a signal that is included in a received signal after logarithmic amplification processing and is derived from a reflected wave or a scattered wave having a tissue characteristic inside the living body.
The speckle signal level may be input directly by the operation of the operation input unit 201 by the user, or may be acquired from an external memory, a communication network, or the like.

In the present embodiment, the speckle detection unit 303 is a predetermined region in which speckles appear from an ultrasonic image (reference image) displayed on the display unit 207 in response to an operation of the operation input unit 201 by the user. Speckle region) is selected, and the speckle signal level corresponding to the selected speckle region is specified. Note that the ultrasonic image data of the reference image is obtained by performing luminance conversion based on the conversion condition in the initial state before adjustment of the conversion condition by the adjustment unit 304.
For example, if FIG. 3 shows the luminance distribution of the reference image, the speckle detection unit 303 performs a plurality of speckle regions (for example, in FIG. 3) on the reference image in accordance with the operation of the operation input unit 201 by the user. Region L1, L2, L3), signal levels corresponding to the plurality of specified speckle regions, respectively, and the signal intensity range from the maximum value to the minimum value among them is specified as the speckle signal level. Detect as. The speckle detection unit 303 identifies one speckle region on the reference image in accordance with the operation of the operation input unit 201 by the user, and speckles the signal level corresponding to the identified one speckle region. It is good also as what detects as this signal level. Also, the alternate long and short dash line in the luminance value 16 in FIG. 3 indicates the baseline of system noise.

In the above description, the speckle detection unit 303 specifies the speckle region on the reference image in accordance with the operation of the operation input unit 201 by the user, and determines the speckle signal level from the specified speckle region. However, the present invention is not limited to this, and the speckle signal level may be detected by the following method.
For example, the speckle detection unit 303 may detect a speckle signal level based on a reference signal obtained by transmitting / receiving ultrasonic waves to / from a phantom having substantially the same acoustic characteristics as the subject. good.

Further, the speckle detection unit 303 may detect a speckle signal level by applying the principle of a spatial compound method or a frequency compound method.
Spatial compound method is to transmit and receive ultrasound from multiple different directions to the same part of the subject, acquire multiple received signals, and perform phasing addition of these received signals. This is a method for generating an ultrasonic image based on a signal. In the frequency compound method, ultrasonic waves are transmitted / received to the same part of the subject, a plurality of received signals are acquired, and these received signals are added. This is a method for generating a sound image. In this embodiment, even if the direction and frequency of transmission / reception of ultrasonic waves are different, the appearance of reception signals derived from the reflector inside the subject is substantially the same, so a plurality of reception signals obtained in this way The received signal derived from the reflector inside the subject may be excluded from the data, and the remaining signal may be detected as the speckle signal level.

Further, the speckle detection unit 303 is derived from the signal level of the received signal derived from the reflector inside the subject and the speckle in the signal distribution of the received signal after the envelope detection process and the logarithmic amplification process are performed. It is also possible to detect a speckle-derived signal level-specific distribution based on the difference in distribution from the received signal level, thereby detecting the speckle signal level.
Furthermore, when ultrasonic waves are transmitted / received to / from the subject, for example, two types of speckles may appear on the outside and inside of the boundary portion of the reflector inside the subject. In such a case, the speckle detection unit 303 may detect one of the two types of speckles as the speckle signal level. In addition, two or more types of speckles may appear on the ultrasonic image. Even in such a case, the speckle detection unit 303 selects one of the two or more types of speckles. What is necessary is just to make it detect as a signal level of a speckle.

The adjustment unit 304 uses the envelope detection processing and the logarithm based on the signal level of the speckle detected by the speckle detection unit 303 and the signal level of the received signal based on the reflected ultrasound from the reflector inside the subject. The conversion condition for converting the received signal subjected to the amplification process into a luminance signal is adjusted. Specifically, the adjustment unit 304 specifies the maximum value and the minimum value of the speckle signal level, and based on each luminance value of the luminance signal obtained by luminance conversion of the specified maximum value and minimum value, Adjust input / output characteristics of gamma, gain and dynamic range as conversion conditions.
For example, when the speckle detection unit 303 detects the signal levels corresponding to the regions L1, L2, and L3 in FIG. 3 as the speckle signal level, the adjustment unit 304 sets the maximum value of the speckle signal level. Then, the luminance value 96 and the luminance value 16 are calculated by converting the luminance from the maximum value and the minimum value of the signal level of the specified speckle and calculating the luminance value 96 and the luminance value 16 as a reference. Adjust input / output characteristics of gain and dynamic range.

  The luminance conversion unit 305 includes a gamma adjustment unit 305a, a gain adjustment unit 305b, and a dynamic range adjustment unit 305c. The luminance conversion unit 305 is based on the input / output characteristics of the gamma adjustment unit 305a, the input / output characteristics of the gain adjustment unit 305b, and the input / output characteristics of the dynamic range adjustment unit 305c adjusted by the adjustment unit 304. The received signal after the processing is converted into a luminance signal, and ultrasonic image data is generated.

  Hereinafter, the adjustment of input / output characteristics of the gamma adjustment unit 305a, the gain adjustment unit 305b, and the dynamic range adjustment unit 305c by the adjustment unit 304 will be specifically described with reference to FIGS. 4 to 6, the broken line indicates the input / output characteristics in the initial state, and the solid line indicates the input / output characteristics after being adjusted by the adjustment unit 304.

The adjustment unit 304 is obtained by specifying the maximum value and the minimum value of the speckle signal level detected by the speckle detection unit 303 and converting the luminance from the maximum value and the minimum value of the specified speckle signal level. The input / output characteristics of the gamma adjustment unit 305a are adjusted so that the luminance difference between the luminance values of the luminance signals increases.
Specifically, for example, as illustrated in FIG. 4, the adjustment unit 304 specifies the maximum value A and the minimum value B of the signal level of the speckle detected by the speckle detection unit 303 and specifies the specified speckle. The luminance signal R2 obtained by converting the luminance R2 between the luminance values A2 and B2 of the luminance signal obtained by performing luminance conversion from the maximum value A and the minimum value B of the signal level is obtained by performing luminance conversion with the input / output characteristics before adjustment. The input / output characteristics of the gamma adjustment unit 305a are adjusted so as to be larger than the luminance difference R1 between the luminance values A1 and B1. That is, the adjustment unit 304 reduces the slope of the input / output characteristics as a signal having a value smaller than the minimum value B of the speckle signal level as noise, and in the range from the minimum value B to the maximum value A of the speckle signal level. Is adjusted to increase the slope of the input / output characteristics. As a result, the speckle signal level in the input / output characteristics after adjustment is greater than the luminance difference R1 between the luminance values A1 and B1 of the luminance signal obtained by converting the luminance of the speckle signal level in the input / output characteristics before adjustment. The luminance difference R2 between the luminance values A2 and B2 of the luminance signal obtained by converting the luminance is larger. Therefore, the luminance conversion unit 305 can generate an ultrasonic image in which speckles are enhanced and noise is suppressed by performing luminance conversion on the received signal based on the input / output characteristics of the adjusted gamma adjustment unit 305a. it can.

Further, the adjustment unit 304 specifies the maximum and minimum values of the speckle signal level detected by the speckle detection unit 303, and performs luminance conversion on the maximum and minimum values of the specified speckle signal level. The input / output characteristics of the gain adjustment unit 305b are adjusted so that each luminance value of the obtained luminance signal is included in the intermediate value of luminance.
Specifically, for example, as illustrated in FIG. 5, the adjustment unit 304 specifies the maximum value A and the minimum value B of the speckle signal level detected by the speckle detection unit 303, and specifies the specified speckle. The input / output characteristics of the gain adjustment unit 305b are adjusted so that the luminance values A2 and B2 of the luminance signal obtained by luminance conversion from the maximum value A and the minimum value B of the signal level are included in the intermediate value of luminance. . That is, the adjustment unit 304 preferably sets the luminance values A2 and B2 to 20 to 40% of the luminance so that the luminance value A2 is smaller than 100% of the luminance and the luminance value B2 is larger than 0% of the luminance. The input / output characteristics of the gain adjusting unit 305b are adjusted so as to be included. In FIG. 5, the luminance values of the luminance signal obtained by performing luminance conversion from the maximum value A and the minimum value B of the speckle signal level with the input / output characteristics before adjustment are A1 and B1. The adjustment unit 304 adjusts the input / output characteristics of the gain adjustment unit 305b so that the luminance value of the luminance signal derived from the reflector inside the subject does not exceed 100% of the luminance. The luminance conversion unit 305 performs luminance conversion on the received signal based on the input / output characteristics of the adjusted gain adjustment unit 305b, thereby generating an ultrasonic image in which speckles are not too bright or too dark. it can.

Further, the adjustment unit 304 specifies the maximum and minimum values of the speckle signal level detected by the speckle detection unit 303, and performs luminance conversion on the maximum and minimum values of the specified speckle signal level. The input / output characteristics of the dynamic range adjustment unit 305c are adjusted so that the luminance difference between the luminance values of the obtained luminance signal becomes large, and the luminance values of the luminance signal are included in the intermediate luminance value. .
Specifically, for example, the adjustment unit 304 first specifies the maximum value A and the minimum value B (see FIG. 6) of the speckle signal level detected by the speckle detection unit 303. As shown in FIG. 6, the adjustment unit 304 determines that the luminance difference R2 between the luminance values A2 and B2 of the luminance signal obtained by performing luminance conversion from the maximum value A and the minimum value B of the specified speckle signal level. The luminance values A2 and B2 are intermediate values of luminance (for example, the luminance values A2 and B2 so as to be larger than the luminance difference R1 between the luminance values A1 and B1 of the luminance signal obtained by luminance conversion based on input / output characteristics before adjustment. , The input / output characteristics of the dynamic range adjustment unit 305c are adjusted so as to be included in 20 to 40% of luminance). That is, the adjustment unit 304 adjusts the input / output characteristics of the dynamic range adjustment unit 305c so as to increase the slope of the input / output characteristics. The adjustment unit 304 adjusts the input / output characteristics of the dynamic range adjustment unit 305c so that the luminance value of the luminance signal derived from the reflector inside the subject does not exceed 100% of the luminance. The luminance conversion unit 305 converts the luminance of the received signal based on the input / output characteristics of the adjusted dynamic range adjustment unit 305c, thereby enhancing speckles and making the speckles too bright or too dark. No ultrasound images can be generated.
The adjustment unit 304 adjusts the input / output characteristics of the gamma adjustment unit 305a, the input / output characteristics of the gain adjustment unit 305b, and the input / output characteristics of the dynamic range adjustment unit 305c. It may be adjusted.

  The adjustment unit 304 may adjust input / output characteristics of gamma, gain, and dynamic range for each depth inside the subject. In this case, for example, the speckle detection unit 303 identifies the regions L1, L2, and L3 (see FIG. 3) according to the operation of the operation input unit 201 by the user, and corresponds to the identified regions L1, L2, and L3. Each signal level is specified and detected as a speckle signal level. Then, the adjustment unit 304 reduces the luminance difference between the luminance values of the luminance signals obtained by performing luminance conversion on the speckle signal levels in the regions L1, L2, and L3 detected by the speckle detection unit 303, respectively. Adjust input / output characteristics of gamma, gain, and dynamic range for each depth. That is, the adjustment unit 304 adjusts the input / output characteristics of gamma, gain, and dynamic range so that the luminance values of the luminance signals obtained by luminance conversion of the speckle signal levels in the regions L1, L2, and L3 are equal. Adjust for each depth. Thereby, it is possible to obtain an ultrasonic image in which the brightness of speckle is constant at each depth on the image.

  The memory unit 205 illustrated in FIG. 1 is configured by a semiconductor memory such as a DRAM (Dynamic Random Access Memory), for example, and stores the B-mode image data transmitted from the image generation unit 204 in units of frames. That is, it can be stored as frame image data. The stored frame image data is transmitted to the DSC 206 under the control of the control unit 208. The memory unit 205 is composed of a large-capacity memory capable of holding about 10 seconds of frame image data. For example, the last 10 seconds of frame image data is held by a FIFO (First-In First-Out) method. Is done.

  The DSC 206 converts the frame image data received from the memory unit 205 into an image signal based on a television signal scanning method, and outputs the image signal to the display unit 207.

  The display unit 207 may be a display device such as an LCD (Liquid Crystal Display), a CRT (Cathode-Ray Tube) display, an organic EL (Electronic Luminescence) display, an inorganic EL display, or a plasma display. The display unit 207 displays an image on the display screen in accordance with the image signal output from the DSC 206. Note that a printing device such as a printer may be applied instead of the display device so that print output is possible.

The control unit 208 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), and reads various processing programs such as a system program stored in the ROM to read the RAM. The operation of each part of the ultrasonic diagnostic imaging apparatus 20 is centrally controlled according to the developed program.
The ROM is configured by a nonvolatile memory such as a semiconductor and the like, and a system program corresponding to the ultrasonic diagnostic imaging apparatus 20 and various processing programs that can be executed on the system program, such as a brightness adjustment control process described later, etc. The various data are stored. These programs are stored in the form of computer-readable program code, and the CPU sequentially executes operations according to the program code.
The RAM forms a work area for temporarily storing various programs executed by the CPU and data related to these programs.

  Next, the brightness adjustment control process executed by the ultrasonic diagnostic imaging apparatus 20 configured as described above will be described with reference to FIG.

  First, the speckle detection unit 303 selects a speckle region on the reference image displayed on the display unit 207 in accordance with the operation of the operation input unit 201 by the user (step S101).

  Next, the speckle detection unit 303 identifies the signal level corresponding to the speckle region selected in step S101 from the received signal that is the basis of the reference image, and uses the identified signal as the speckle signal level. Detect (step S102).

Next, the adjustment unit 304 adjusts the input / output characteristics of gamma, gain, and dynamic range based on the detected speckle signal level and the received signal level derived from the reflector inside the subject. (Step S103).
Specifically, the adjustment unit 304 specifies the maximum and minimum values of the speckle signal level, and each luminance signal obtained by performing luminance conversion on the specified maximum and minimum values of the speckle signal level. The input of the gamma adjustment unit 305a is such that there is a large difference in luminance values, and each luminance value of the luminance signal obtained by luminance conversion of the maximum and minimum speckle signal levels is included in the intermediate luminance value. The output characteristic, the input / output characteristic of the gain adjustment unit 305b, and the input / output characteristic of the dynamic range adjustment unit 305c are adjusted. The adjustment unit 304 also includes an input / output characteristic of the gamma adjustment unit 305a, an input / output characteristic of the gain adjustment unit 305b, and the like so that the luminance value of the luminance signal derived from the reflector inside the subject is included in the intermediate value of luminance. The input / output characteristics of the dynamic range adjustment unit 305c are adjusted.

Finally, the luminance converting unit 305 converts the acquired received signal into a luminance signal based on the input / output characteristics adjusted by the adjusting unit 304 in step S103, and generates ultrasonic image data (step S104). ).
Thereby, the brightness adjustment control process is terminated.

In addition, an ultrasonic image processing method using the above-described ultrasonic image diagnostic apparatus 20 of the present embodiment will be described.
First, a transmission ultrasonic wave is output to the subject by the ultrasonic probe 20b, and a reception signal is acquired by receiving a reflected ultrasonic wave from the subject (ultrasonic transmitting / receiving step). Various processing is performed on the acquired reception signal by the amplifier, A / D conversion circuit, and phasing addition circuit of the reception unit 203.
Next, the speckle signal level is input by the operation input unit 201 (speckle input process). The input speckle signal level may be a signal level specified from the speckle region on the reference image generated by the image generation unit 204, or may be higher than a phantom having substantially the same acoustic characteristics as the subject. The signal level specified from the acquired reference signal may be obtained by transmitting and receiving sound waves to acquire the reference signal.
Next, the conversion condition for luminance conversion of the received signal subjected to various processes by the receiving unit 203 is adjusted based on the input speckle signal level (condition adjusting step). That is, the input / output characteristics of the gamma adjustment unit 305a, the input / output characteristics of the gain adjustment unit 305b, and the input / output characteristics of the dynamic range adjustment unit 305c are adjusted so that speckle is emphasized.
Finally, based on the input / output characteristics of the adjusted gamma, gain, and dynamic range, the received signal is converted into a luminance signal to generate ultrasonic image data (image generation step). That is, after performing envelope detection processing and logarithmic amplification processing on the reception signal subjected to various processing by the reception unit 203, the reception signal is converted into a luminance signal based on the input / output characteristics adjusted in the condition adjustment step. Convert. Thereby, an ultrasonic image in which speckle is emphasized can be acquired, and accurate ultrasonic image diagnosis in consideration of speckle can be performed.

  As described above, according to the present embodiment, the signal level of the speckle is detected from the reception signal acquired by the ultrasonic probe 20b, and the received signal is determined based on the detected signal level of the speckle. Since the conversion condition for conversion to the luminance signal is adjusted and the luminance of the luminance signal is adjusted, an ultrasonic image in which speckle is emphasized can be acquired. This makes it possible to perform accurate ultrasonic image diagnosis in consideration of speckle.

  In addition, the conversion conditions are adjusted in consideration of not only the detected speckle signal level but also the signal level of the received signal based on the reflected signal from the reflector inside the subject. In this case, it is possible to acquire an ultrasonic image in which the outline of the reflector is emphasized without the brightness of the reflector being too bright. This makes it possible to perform more accurate ultrasonic image diagnosis in consideration of speckle.

  In addition, the speckle region is specified according to the operation of the operation input unit 201 by the user, and the signal level of the speckle is detected from the specified speckle region. Therefore, the signal level indicating the speckle is determined based on the user's judgment. It can be detected and the convenience for the user can be improved.

  Further, the maximum value and the minimum value of the speckle signal level detected from the reception signal acquired by the ultrasonic probe 20b are specified, and converted from the maximum value and the minimum value of the specified speckle signal level. Since the conversion condition for converting the received signal into the luminance signal is adjusted so that the luminance difference between the luminance values of the luminance signal obtained in this way is increased, the speckle contrast is increased on the generated ultrasonic image, An ultrasonic image in which speckle is emphasized can be acquired.

  Further, the maximum value and the minimum value of the speckle signal level detected from the reception signal acquired by the ultrasonic probe 20b are specified, and converted from the maximum value and the minimum value of the specified speckle signal level. The conversion conditions for converting the received signal into a luminance signal are adjusted so that each luminance value of the luminance signal obtained is included in the intermediate value of the luminance, so speckles are too bright on the generated ultrasonic image. An ultrasonic image that allows easy observation of speckles that are not too dark can be acquired.

  In the present embodiment, an ultrasonic image based on the ultrasonic image data stored in the ultrasonic diagnostic imaging apparatus is output to the display unit, but a display device externally connected to the ultrasonic diagnostic imaging apparatus, The ultrasonic image data may be output to a printing apparatus or an external device connected to a network or the like.

  In this embodiment, the input / output characteristics of gamma, gain, and dynamic range are based on both the speckle signal level and the signal level of the received signal based on the reflected ultrasound from the reflector inside the subject. However, the input / output characteristics of gamma, gain, and dynamic range may be adjusted based only on the speckle signal level.

  In the present embodiment, the maximum value and minimum value of the speckle signal level are specified, and each luminance value of the luminance signal obtained by converting from the maximum value and minimum value of the specified speckle signal level is determined. The input / output characteristics of the gain adjustment unit are adjusted so that is included in the intermediate value of the brightness. However, if the speckles on the displayed ultrasound image are too bright, the user operation input unit In response to the above operation, the input / output characteristics of gamma, gain, and dynamic range may be readjusted so that the speckle brightness is reduced.

In the present embodiment, the speckle signal level is detected, and the input / output characteristics of gamma, gain, and dynamic range are adjusted based on the detected speckle signal level. It has a storage unit that stores the speckle signal level, and the gamma and gain based on the speckle signal level selected from the signal levels stored in the storage unit according to the operation of the operation input unit by the user The input / output characteristics of the dynamic range may be adjusted.
In addition, it has a storage unit that stores multiple types of input / output characteristics of gamma, gain, and dynamic range that have been adjusted in advance, and from among the input / output characteristics stored in the storage unit according to the operation of the operation input unit by the user The received signal may be subjected to luminance conversion based on the selected input / output characteristics.

  In this embodiment, the amplifier of the receiving unit amplifies the received signal at a preset amplification factor for each individual path corresponding to each transducer. However, the signal level of speckle is detected. Then, based on the detected speckle signal level, the received signal may be amplified by changing the amplification factor so that the speckle signal level is constant at each depth.

  In the present embodiment, the input / output characteristics of gamma, gain, and dynamic range are adjusted based on the speckle signal level specified from the reference image, and ultrasonic waves of other frames are adjusted based on the adjusted input / output characteristics. Although the image data is generated, the ultrasonic image data may be generated again from the reception signal that is the basis of the reference image based on the adjusted input / output characteristics.

  In this embodiment, the received signal is converted in luminance based on the input / output characteristics of gamma, gain, and dynamic range adjusted based on the detected speckle signal level. In addition, after the luminance conversion based on the input / output characteristics of the dynamic range, the luminance of the luminance signal may be adjusted based on the input / output characteristics of the adjusted gamma.

  Further, in the present embodiment, the brightness difference between the brightness values of the brightness signal obtained by conversion from the maximum value and the minimum value of the speckle signal level is increased, and each brightness value is an intermediate brightness level. By adjusting the input / output characteristics of gamma, gain, and dynamic range so as to be included in the value, an ultrasonic image with enhanced speckles was acquired, but depending on the operation of the operation input unit by the user, The input / output characteristics of gamma, gain, and dynamic range may be adjusted so that an ultrasonic image with suppressed speckles can be acquired.

  In the present embodiment, an example in which a hard disk, a semiconductor nonvolatile memory, or the like is used as a computer-readable medium of the program according to the present invention is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also used as a medium for providing program data according to the present invention via a communication line.

DESCRIPTION OF SYMBOLS 20 Ultrasonic diagnostic imaging apparatus 20a Ultrasonic diagnostic imaging apparatus main body 20b Ultrasonic probe 20c Cable 201 Operation input part (operation part)
202 Transmission unit 203 Reception unit 204 Image generation unit 205 Memory unit 206 DSC
207 Display unit 208 Control unit 301 Envelope detection processing unit 302 Logarithmic amplification processing unit 303 Speckle detection unit 304 Adjustment unit 305 Luminance conversion unit 305a Gamma adjustment unit 305b Gain adjustment unit 305c Dynamic range adjustment unit

Claims (7)

An ultrasonic probe that outputs a transmission ultrasonic wave to the subject and receives a reflected ultrasonic wave from the subject to obtain a reception signal;
An image generation unit that converts a reception signal acquired by the ultrasonic probe into a luminance signal and generates ultrasonic image data from the luminance signal;
A speckle detection unit for detecting a signal level of speckles from a reception signal acquired by the ultrasonic probe;
An ultrasound image, comprising: an adjustment unit that adjusts a conversion condition for converting the received signal into a luminance signal based on the signal level of the speckle detected by the speckle detection unit. Diagnostic device.   The adjustment unit receives the speckle signal level detected by the speckle detection unit and the signal level of the received signal based on the reflected ultrasonic wave from the reflector inside the subject. 2. The ultrasonic diagnostic imaging apparatus according to claim 1, wherein a conversion condition for converting the signal into a luminance signal is adjusted. Further equipped with an operation unit that can be operated by the user,
3. The speckle detection unit according to claim 1, wherein the speckle detection unit specifies a speckle region according to an operation by the operation unit, and detects a signal level of the speckle from the specified speckle region. Ultrasound image diagnostic equipment.   The adjustment unit specifies a maximum value and a minimum value of a speckle signal level detected from a reception signal acquired by the ultrasonic probe, and specifies a maximum value and a minimum value of a signal level of the specified speckle. 4. The conversion condition for converting the received signal into a luminance signal by the image generation unit is adjusted so that a luminance difference between luminance values of luminance signals obtained by converting from the luminance signal becomes large. The ultrasonic diagnostic imaging apparatus according to any one of the above.   The adjustment unit specifies a maximum value and a minimum value of a speckle signal level detected from a reception signal acquired by the ultrasonic probe, and specifies a maximum value and a minimum value of a signal level of the specified speckle. 2. The conversion condition for converting the received signal into a luminance signal by the image generation unit is adjusted so that each luminance value of the luminance signal obtained by converting the luminance signal is included in an intermediate luminance value. 4. The ultrasonic diagnostic imaging apparatus according to any one of 3.   The adjustment unit is configured so that the luminance difference between luminance values of luminance signals obtained by converting the signal levels of speckles detected from received signals at different depths inside the subject is reduced. The ultrasonic diagnostic imaging apparatus according to claim 1, wherein a conversion condition for converting a received signal into a luminance signal is adjusted for each depth. An ultrasonic transmission / reception step of outputting a transmission ultrasonic wave to the subject and acquiring a reception signal by receiving a reflected ultrasonic wave from the subject; and
Speckle input process for inputting speckle signal level;
A condition adjusting step for adjusting a conversion condition for converting a received signal into a luminance signal based on the signal level of the input speckle;
An image generation step of converting the received signal acquired in the ultrasonic transmission / reception step into a luminance signal based on the adjusted conversion condition and generating ultrasonic image data from the luminance signal, An ultrasonic image processing method.

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