JP2007117168A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform an automatic image quality adjustment by attaching importance to the adjustment of the image quality in a region of interest in an ultrasonic diagnostic apparatus. <P>SOLUTION: Acquired ultrasonic B mode data are divided into regions (S16) according to a set dividing pattern (S14). Then, the histogram on the luminance is prepared for each region (S18), and the peak luminance A and the luminance width B are computed to take a difference between target values and calculated value (S24). The obtained difference data ΔA and ΔB for the region are weighted and averaged (S26) according to the irregularly set weighting for evaluation (S28), and the image quality of the whole ultrasonic B mode data is evaluated (S30). By approximating the evaluated value to the target value, the automatic image quality adjusting process with importance attached to the image quality of the greatly weighted concerned region is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for displaying an ultrasonic image based on a received ultrasonic echo, and more particularly to a technique for adjusting the image quality of a displayed image.

  In the ultrasonic diagnostic apparatus, an ultrasonic image is displayed in a format such as B mode (tomographic mode) or M mode (motion mode) based on the received ultrasonic echo. At the time of display, image quality adjustment processing such as gain adjustment and dynamic range adjustment is performed. Such image quality adjustment processing is often automatically performed based on settings.

  Patent Documents 1 to 3 below disclose techniques for performing gain adjustment or contrast (dynamic range) adjustment of an ultrasonic image based on a histogram of luminance of the entire ultrasonic image. However, in these techniques, the luminance is evaluated for the entire ultrasonic image, and the luminance evaluation is not performed for the portion of the ultrasonic image. Japanese Patent Application Laid-Open No. 2004-228620 discloses a technique for dividing a DSC (digital scan converter) output area into nine parts, determining whether the image is appropriate or inappropriate for each area, and determining whether to change the gain by majority vote. It is disclosed. However, this technique also only evaluates the overall luminance of the ultrasound image with the same weight.

JP-A-5-245147 JP-A-6-105850 JP 62-117534 A Japanese Patent Laid-Open No. 7-236637

  In an ultrasonic diagnostic apparatus, it is desired to display an ultrasonic image of an area in which an operator is interested with appropriate image quality. However, for example, in the conventional automatic image quality adjustment processing, optimization according to the diagnosis area has not been performed. That is, the image quality adjustment reflecting the image quality of the region of greatest interest in diagnosis is not performed, and the image quality as intended by the operator may not be obtained.

  An object of the present invention is to establish a technique for performing image quality adjustment processing with emphasis on image quality adjustment of a region of interest in an ultrasonic diagnostic apparatus.

  Another object of the present invention is to establish a technique for changing an image quality adjustment mode in accordance with a diagnostic object or a diagnostic method in an ultrasonic diagnostic apparatus.

  The ultrasonic diagnostic apparatus according to the present invention includes an ultrasonic image generation unit that generates an ultrasonic image based on a received ultrasonic echo, and the generated ultrasonic image is not unique to each region of the ultrasonic image. In accordance with the evaluation weight set in the same manner, image quality evaluation means for evaluating the image quality, image quality adjustment means for adjusting the image quality of the ultrasonic image according to the result of the image quality evaluation, and display means for displaying the ultrasonic image whose image quality has been adjusted And comprising.

  The ultrasonic diagnostic apparatus is an apparatus having an image processing function and a display function of an ultrasonic moving image. An ultrasonic diagnostic apparatus typically includes a transmission apparatus that transmits ultrasonic waves and a reception apparatus that receives reflected waves. However, these apparatuses may be configured to be externally attached. The ultrasonic image generating means is means for generating an ultrasonic image based on the received ultrasonic echo. That is, based on the ultrasonic waves transmitted and received by the ultrasonic diagnostic apparatus itself or an external apparatus, an ultrasonic image indicating the internal structure and movement of a diagnosis target such as a human body is generated. The expression format of the ultrasonic image is not particularly limited, and various types such as a B-mode image, an M-mode image, and a color Doppler image can be employed.

  The image quality evaluation means is means for evaluating the image quality of the generated ultrasonic image. The evaluation of the image quality is performed based on evaluation weights set non-uniformly for each region of the ultrasonic image. That is, a large evaluation weight is given to an important part, and 0 (not subject to evaluation) or a small evaluation weight is given to an unimportant part. The weighting pattern of the evaluation weight may be set by the user, the standard setting may be used, or may be automatically / changed as appropriate. As an example of the standard setting, there is a mode in which a higher evaluation weight is set in the central portion of the image in consideration of the possibility that the central portion of the image becomes a region of interest. It is also effective to prepare a “spot mode” that gives an evaluation weight other than 0 for a certain part. The spot mode can be expected to exert its power in, for example, examination of a heart having a large contrast difference. Of course, an “average mode” in which an evaluation weight equal to the entire area of the image is given by setting switching can also be adopted. The average mode is suitable for, for example, examination of a mammary gland that is easily affected by a fat layer and tends to have a large overall luminance fluctuation. The image quality should also be referred to as an index that influences the appearance of the display image, and is expressed by, for example, luminance, contrast, variety of colors, noise, and the like. The evaluation of image quality is typically performed by setting a target image quality as an evaluation standard and comparing it.

  The image quality adjustment unit is a unit that performs image quality adjustment based on the evaluation result of the image quality. The image quality adjustment is a process for adjusting the image quality that is the appearance of the display image, and specifically includes gain adjustment, dynamic range adjustment, color range adjustment, gradation conversion, filter processing, and the like. The image quality adjustment may be performed on an analog image (typically, an image before processing by a DSC (digital scan converter)) or an image after digital conversion (typically an image after DSC processing). You may go. The image quality-adjusted ultrasonic image is displayed on the display screen by the display means.

  According to this configuration, the image quality is evaluated according to the evaluation weight in which a value different from the other partial areas is set for a partial area of the image, and the image quality adjustment is performed based on the evaluation. Therefore, by assigning a large evaluation weight to the region of interest, it is possible to perform image quality adjustment processing that emphasizes image quality adjustment of the region of interest. Note that the image quality adjustment may be a manual image quality adjustment executed according to a user instruction under this evaluation weight, but from the viewpoint of reducing the user burden, it is particularly desirable that the image quality adjustment be an automatic image quality adjustment executed according to programming or the like.

  In one aspect of the ultrasonic diagnostic apparatus of the present invention, the evaluation weight is set so that a partial region of the ultrasonic image is excluded from the evaluation target. That is, by appropriately setting the evaluation weight value, it is possible to exclude a partial region of the ultrasonic image from the evaluation target or to set only a partial region of the ultrasonic image as the evaluation target. In the aspect of the ultrasonic diagnostic apparatus of the present invention, the evaluation weight is set for each small region obtained by dividing all or part of the ultrasonic image into a plurality of parts. Examples of the area division include an example in which the entire area of the image is divided into a grid pattern, or a partial area of the image is divided into a grid pattern.

  In one aspect of the ultrasonic diagnostic apparatus of the present invention, the image quality evaluation by the image quality evaluation means is performed based on a histogram analysis of the echo intensity distribution. In the aspect of the ultrasonic diagnostic apparatus of the present invention, the image quality adjustment performed by the image quality adjustment unit may include gain adjustment or dynamic range adjustment.

  In one aspect of the ultrasonic diagnostic apparatus of the present invention, the evaluation weight is set according to a diagnosis object or a diagnosis method, and the image quality adjustment unit sets the result of the image quality evaluation according to the diagnosis object or the diagnosis method. Image quality adjustment is performed to achieve the target image quality. The diagnosis target refers to organs such as the heart and kidneys, blood flow, and the like. Information about the diagnosis target can be acquired based on user input such as the organ name, etc., and can also be acquired based on the subject to be examined (cardiac surgery, obstetrics, etc.) and the part name (chest, abdomen) It is. The diagnostic method is information on a setting mode on the apparatus side, and indicates a diagnostic depth (focus depth), a frequency, a probe model number, an ultrasonic scanning method, and the like. The region of interest and easy-to-see image quality vary depending on the diagnosis target and the diagnosis method. Therefore, the evaluation weight and the target image quality are set according to the diagnosis target or the diagnosis method.

  In one aspect of the ultrasonic diagnostic apparatus of the present invention, the image quality adjustment in the image quality adjustment means is performed in the ultrasonic image when the image quality adjustment has already been performed by a user input on a partial area of the ultrasonic image. This is done except for the area. As an example in which image quality adjustment is performed on a partial area by user input, processing such as STC (TGC) or LGC can be given. An evaluation weight value that is not subject to evaluation may be set for an area where such processing is performed, or an evaluation weight value that is subject to evaluation may be set. In the aspect of the ultrasonic diagnostic apparatus of the present invention, the ultrasonic image is a tomographic image (B-mode image).

  FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus 10 according to the present embodiment. The ultrasonic diagnostic apparatus 10 includes a probe 12 having a plurality of ultrasonic transducers. The probe 12 transmits an ultrasonic wave based on the transmission signal input from the transmitter 14, receives the reflected ultrasonic wave, converts it into a reception signal that is an electrical signal, and outputs the received signal to the reception amplifier 16. Scanning modes, frequencies, focal points, and the like in ultrasonic transmission / reception can be set in various ways, and are generally changed as appropriate according to the diagnosis site, display mode, and the like. For the sake of simplicity, the following description mainly refers to a mode in which a B-mode image (tomographic image) is obtained continuously and displayed as a moving image, but images in other modes can be processed in the same manner. The received signal is finally displayed as a (moving) image after subsequent processing, and the received signal and the ultrasonic (moving) image are not necessarily clearly distinguished. Therefore, hereinafter, the received signal and the ultrasonic image may be described as being the same.

  The reception amplifier 16 is an amplifier that amplifies the reception signal. Based on the instruction, the reception amplifier 16 performs STC (Sensitivity Time Control; image quality adjustment for each depth direction, sometimes referred to as TGC (Time Gain Control)) processing and LGC (Lateral Gain Control; image quality for each scanning direction). Adjustment) is provided. The reception signals for the respective ultrasonic transducers amplified by the reception amplifier 16 are combined by the beam former 18 and further subjected to detection processing by the baseband signal processing unit 20. Then, it is digitized by a DSC (Degital Scan Converter) 22 and converted from an expression format based on scanning into coordinates and resolution based on a display screen. The coordinate-converted signal is sent to a display control unit 24 having a memory for image display, and is displayed on a display unit 26 such as a liquid crystal display.

  The ultrasonic diagnostic apparatus 10 is provided with a histogram processing unit 28. The histogram processing unit 28 receives the detected analog signal from the baseband signal processing unit 20, and evaluates the image quality of the luminance distribution of the ultrasonic tomographic image indicated by the analog signal by histogram analysis. The evaluation is performed nonuniformly for each region of the ultrasonic tomographic image. That is, first, an ultrasonic image is divided into a plurality of regions, and a comparison is made with the gain and dynamic range that are set targets for each region. And the comparison result of each area | region is totaled based on the set non-uniform evaluation weight. As a result, image quality evaluation is performed with an emphasis on a point of interest (region of interest). Note that the histogram processing unit 28 may be configured to perform image quality evaluation based on a digital signal output from the DSC 22 instead of the output from the baseband signal processing unit 20.

  The evaluation result by the histogram processing unit 28 is output to the gain / dynamic range determination unit 30. The gain / dynamic range determination unit 30 adjusts the gain and dynamic range settings based on the result of the image quality evaluation, and determines that the image quality sufficiently converged to the target image quality can be obtained. Fix the dynamic range to that setting. If the gain / dynamic range determination unit 30 determines that the image quality has deviated from the target image quality after fixing the setting, the gain / dynamic range determination unit 30 resumes changing the gain and dynamic range settings.

  The operator can control tomographic image display (B mode display) in the ultrasonic diagnostic apparatus 10 through the operation panel 32. The main control operations include an instruction to freeze an ultrasonic moving image (display a still image), an input of STC setting values used by the receiving amplifier 16, a gain target value used by the histogram processing unit 28, and a dynamic range target value. Diagnosis range designation, subject designation and probe designation input.

  The operation analysis unit 34 analyzes a signal input from the operation panel 32 and gives a necessary command to each component. The operation analysis unit 34 refers to information in the database 36 as necessary. This database 36 stores diagnostic range information, subject information, probe information, etc., and optimal region division modes and target values of gain / dynamic range corresponding to designations such as diagnostic range designation, subject designation, probe designation, etc. Can be found. The timer 38 counts time based on a command from the operation analysis unit 34, and the count result is used as a determination condition in the gain / dynamic range determination unit 30.

  Next, the operation of the ultrasonic diagnostic apparatus 10 will be briefly described. An operator such as a doctor or a laboratory technician performs ultrasonic diagnosis by placing the probe 12 on the body surface of the diagnostic site. The probe 12 performs electronic scanning based on the transmission signal sent from the transmitter 14 and acquires a reception signal corresponding to the reflected wave. The received signal is displayed on the display unit 26 after being subjected to each processing in the receiving amplifier 16, the beam former 18, the baseband signal processing unit 20, the DSC 22 and the display control unit 24. The operator can grasp the internal structure of the diagnosis target and its movement by visually recognizing the displayed tomographic moving image.

  The operator can make various settings for image quality adjustment from the operation panel 32. The setting mode can be implemented in various ways. As an example, a mode in which diagnosis range designation, subject designation, and probe designation are performed. In this designation, for example, a high-frequency ultrasonic wave is designated as a diagnostic range, a cardiac surgery as a subject, and a model number that is used as a probe. In addition, it is also possible to acquire these information from related registration data etc. instead of an operator specifying. For example, probe data can be acquired by automatic probe recognition, or subject information can be acquired from patient data.

  The operation analysis unit 34 determines the optimum image quality adjustment mode corresponding to the input diagnostic range, subject, and probe with reference to the diagnostic range information, subject information, and probe information in the database 36. Based on the determined image quality adjustment mode, the histogram processing unit 28 determines how to divide the region, assigns an evaluation weight to each region, and sets an image quality target value for each region. The area division information 42 indicating whether to do is transmitted.

  The histogram processing unit 28 evaluates the image quality of the image data input from the baseband signal processing unit 20 based on the set region division information 42, and obtains the peak luminance representative value and luminance width representative value 44 obtained as a result. Output to the gain / dynamic range determination unit 30. The gain / dynamic range determination unit 30 starts adjusting the gain and the dynamic range when a signal for which the freeze designation is canceled is sent from the operation panel 32. Then, the gain setting / dynamic range setting 46 is set so as to bring the image quality closer to the target gain value and the dynamic range target value input from the operation panel 32 and output to the baseband signal processing unit 20. As a result, when the gain and dynamic range satisfy the target values, the gain / dynamic range determination unit 30 stops the new gain setting / dynamic range setting 46 and fixes the gain and dynamic range settings. As a result, image display with stable image quality is performed. If the target value is not satisfied, error processing is performed after a predetermined time has elapsed based on the count input from the timer 38.

  Next, an example of image quality evaluation performed by the histogram processing unit 28 will be described in detail with reference to FIGS. 2 to 4.

  FIG. 2 is a flowchart for explaining the image quality evaluation process. When the control for the gain / dynamic range is started based on the user instruction or the programming control (S10), the histogram processing unit 28 first sets the ultrasonic tomographic image (B mode) data to 1 from the baseband signal processing unit 20. A frame is acquired (S12). Then, based on the input (S14) of the area division pattern (for example, 9 areas), the ultrasonic tomographic image data is divided (S16). Subsequently, a histogram indicating how many pixels (or small regions corresponding to the pixels) having each luminance exist for each region is created (S18). Then, by analyzing the histogram, a peak luminance (represented by A) and a luminance width (represented by B) are calculated (S20). The peak luminance is the luminance with the highest frequency, and the luminance width is a measure of the spread width of the luminance distribution on the higher luminance side than the peak luminance.

  Subsequently, differences (ΔA1 to ΔA9, ΔB1 to ΔB9) between the target values of peak luminance / luminance width (all of which may be common but here 9 data) (S22) and the peak luminance / luminance width are calculated (S24). . Based on the weighting coefficients (evaluation weights w1 to w9) for summarizing the evaluation results of each area (S28), a weighted average is made (S26; DA = ΣΔAiwi, DB = ΣΔBiwi). As a result, the peak luminance difference representative value DA and the luminance width difference representative value DB are obtained.

  FIG. 3 is a diagram illustrating an example of area division (S16) in the flowchart of FIG. In this figure, three division examples are shown as FIGS. 3A to 3C. In each figure, the same components are denoted by the same reference numerals, and description thereof is omitted or simplified.

  FIG. 3A shows an example in which the fan-shaped scanning range 100 is divided into three areas of the partial areas 106 to 122 by dividing the fan-shaped scanning range 100 into three in the depth direction 102 and into three in the scanning direction 104. It is possible to set different evaluation weights for each region. Here, a relatively large evaluation weight W is given to the central region 114 that is likely to be a region of interest, and other regions located in the vicinity are assigned. A relatively small evaluation weight w (w <W) is given to the region. In other words, this mode is an evaluation mode that is effective when the display of the central region 114 is emphasized but the peripheral region is desired to be displayed appropriately. The distribution of the evaluation weight between the central area 114 and the peripheral area may be changed according to the importance of the central area 114.

  In FIG. 3B, the scanning range 100 is divided into nine as in FIG. The difference from FIG. 3A is that an evaluation weight W other than 0 is given only to the central region 114, and an evaluation weight of 0 is given to other regions located in the vicinity. This aspect is an aspect that should be referred to as a “spot mode” in which optimum image quality adjustment is performed specifically for the central area 114 and the image quality of the peripheral area is not limited. Therefore, in general, the image quality of the peripheral area is deteriorated, but the image cannot be discriminated. That is, unlike the case where the central area 114 is simply enlarged and displayed, the central area 114 can be diagnosed in detail in relation to the peripheral area.

  In FIG. 3C, as in FIG. 3B, the scanning range 100 is divided into nine, and an evaluation weight of 0 is given to regions other than the central region 114. However, the central region 114 is further divided into three in the depth direction 102 and the scanning direction 104, respectively, and a relatively large evaluation weight W is given to the central region 124 of the obtained nine divided regions, and the other eight A relatively small evaluation weight w (w <W) is given to the area of. This mode gives top priority to the image quality of the central region 124 of the central region 114, takes some consideration into the image quality of other regions of the central region 114, and does not matter the image quality of regions other than the central region 114. It becomes effective in the case. From another point of view, the mode of FIG. 3C smoothly connects the image quality evaluations of the central region 114 and the peripheral region (such as a Gaussian distribution) as compared to the case of FIG. 3B. It can be said that this is an evaluation mode that can accurately cope with a situation where a singular point of luminance exists near the boundary between the central region 114 and the peripheral region.

  The area division can be performed in various other ways, and for example, the number of divisions in the depth direction and the scanning direction can be appropriately changed. Although it is possible to make the division shape irregular, in general, the data of each point is regularly arranged in the depth direction and the scanning direction (vertical and horizontal directions after DSC processing), and regular division is faster. Suitable for processing. It is also possible to variously change the number of evaluation weights and the distribution shape. The evaluation weight functions as a filter for extracting an object of image quality evaluation, and an evaluation weight distribution corresponding to the shape of the portion of interest may be adopted as appropriate.

  The region division and the evaluation weighted distribution can be set by user settings (manual setting by the user or selection from setting candidates by the user). However, as described above, the scanning burden on the user is lightened. Therefore, it is possible to automatically set according to the diagnosis mode. Specifically, when appropriate area division and evaluation weight distribution corresponding to the combination of diagnosis range, subject, probe, etc. are set in advance, and information such as diagnosis range specification, subject specification, probe specification is acquired, An example of adopting region division and evaluation weight distribution as a standard setting is given. For example, when a relatively high frequency ultrasonic frequency is selected in the diagnostic range, a shallow area with relatively little attenuation is considered to be a region of interest. It is effective to set the evaluation weight distribution as standard.

  FIG. 4 is a diagram for explaining the peak luminance and luminance width calculation process (S20) in the flowchart of FIG. In the figure, a histogram is schematically depicted with the horizontal axis representing luminance and the vertical axis representing the number of pixels (or the number of small regions corresponding to pixels). The histogram is drawn excluding the luminance forcibly assigned as the background, and has a small peak 132 of the number of pixels (frequency) on the low luminance side corresponding to the two structures in the region, and the high luminance side FIG. 9 shows a lid mountain structure having a large peak 134 with N pixels. In the image quality evaluation, the luminance of the large peak 134 that is the maximum peak in the histogram is extracted as A. Further, the difference between the luminance A and the luminance which is on the higher luminance side than the luminance A and the number of pixels is N / 2 is extracted as B.

  Next, the image quality adjustment process in the gain / dynamic range determination unit 30 of FIG. 1 will be described with reference to FIGS.

  FIG. 5 is a flowchart showing an image quality adjustment process based on the image quality evaluation result. The image quality adjustment is typically performed for the gain and the dynamic range, but here, only the gain adjustment is shown for the sake of simplicity of explanation. Of course, dynamic range adjustment and other image quality adjustments can also be performed in the same manner as gain adjustment.

  The gain adjustment is started when a freeze release command (S40) is issued from the operation panel 32. That is, when the display of the still image is canceled and the display of the moving image in real time is resumed, the image quality adjustment is performed according to the displayed moving image. When the gain adjustment is started, first, measurement of the time required for the adjustment process is started based on the count of the timer 38 (S42). Then, based on the image quality evaluation result of the histogram processing unit 28, it is determined whether or not the peak luminance difference representative value DA has approached the target value with an error within EA (S44).

  If DA is not sufficiently close to the target value (DA ≧ EA), it is determined whether or not the elapsed time at that time exceeds the time for which adjustment should be completed (S46). Then, when the time to finish the adjustment has passed, appropriate error processing is performed (S48). On the other hand, if the time to finish the adjustment has not elapsed, the sizes of DA and EA are evaluated according to the result of the next image quality evaluation (S44).

  When DA is close to the target value (DA <EA), the convergence time measurement is started based on the count of the timer 38 (S50). The convergence time is a time during which the condition of DA <EA is maintained. When the convergence time exceeds the set time, it is determined that the gain has been sufficiently adjusted. Therefore, whether or not DA <EA is evaluated (S52), and if DA ≧ EA, that is, if the peak luminance deviates from the target value due to an error of EA, the convergence time of The measurement is stopped (S54), and the process returns to step S44 again to repeat the determination of whether DA <EA is satisfied. On the other hand, if DA <EA is satisfied, it is determined each time whether the convergence time has exceeded the set time (S56). If it is determined that the gain has been exceeded, the gain adjustment is stopped (S58), and the gain adjustment process ends (S60).

  The error processing shown in step S48 can be executed in various ways. For example, when the peak luminance value of the ultrasonic moving image is much lower than the target value, there is a possibility that the operator has not performed the ultrasonic inspection, and error processing for instructing the stop of the ultrasonic transmission can be considered. . Further, when the peak luminance value of the ultrasonic moving image is much higher than the target value, there is a possibility that the ultrasonic output is too high, and an error process for instructing a decrease in transmission output can be considered.

  Furthermore, when there is a large difference between the peak luminance value of a region with a relatively high evaluation weight (region of interest) and the peak luminance value of a region with a relatively small evaluation weight (non-interest region such as a peripheral region), the acoustic impedance There is a possibility that a localized structure with a different is drawn. Examples of such situations include high-intensity echo structures such as transmission lines, diaphragms and digestive organ contents, and low-intensity echo structures such as acoustic shadows such as heart chambers and stones. Can be mentioned. Therefore, in such a case, if only the peak luminance value of the region of interest is different from that of the non-region of interest, it is highly likely that a localized structure is being observed, and the gain setting at that time is fixed. Error processing that continues the display can be considered. Further, in such a case, when there is a protruding peak in a part of the non-interest region, STC processing or LGC processing is prompted for that part so that image quality adjustment is separately performed for that part and the other part. Or error processing in which automatic STC processing or automatic LGC processing is performed. In general, STC processing and LGC processing are performed in a fan-shaped geometric shape before DSC processing as shown in FIG. For this reason, when image quality adjustment is performed by separately treating regions subjected to STC processing or LGC processing, it can be said that image quality adjustment is preferably performed on image data before DSC processing.

  FIG. 6 is a graph showing the temporal change in the error between the image quality and the target value, and explains the progress of image quality adjustment. The vertical axis represents an error between the image quality and the target value. When applied to the example shown in FIG. 5, the vertical axis corresponds to a value obtained by evaluating the peak luminance difference representative value DA with a sign. A point where the memory on the vertical axis is 0 represents a point where the error is 0 and the image quality matches the target value. The cancellation upper limit value 142 and the cancellation lower limit value 144 shown on the vertical axis indicate a range in which it is determined that the image quality is sufficiently close to the target value. If applied to the example shown in FIG. It corresponds to. On the vertical axis, a restart upper limit value 146 that is larger than the suspension upper limit value 142 and a restart lower limit value 148 that is smaller than the suspension lower limit value 144 are written. These are values used as conditions for restarting image quality adjustment after it is determined that the image quality has converged to the target value and image quality adjustment is stopped. The flow of image quality adjustment processing will be described below according to the error curve 140 shown in the graph.

  The error curve 140 is far below the level of error 0 immediately after the freeze is disclosed and adjustment is started, and the image quality is greatly deviated from the target value. However, the value rapidly approaches an error of 0 by image quality adjustment, and reaches the stop lower limit 144 at the time of reference numeral 150. In this case, the measurement of the convergence time is started as shown in FIG. 5, but here, at the point of reference numeral 152, the suspension upper limit value 142 is temporarily exceeded, and the image quality adjustment is continued. When the stop upper limit 142 is reached at the time indicated by reference numeral 154, the value between the stop upper limit 142 and the stop lower limit 144 continues to be displayed until the time indicated by reference numeral 156 at which the convergence time Δt elapses. Therefore, the image quality adjustment is temporarily ended at the time indicated by reference numeral 156, and thereafter, the fixed image quality adjustment for the input data is performed according to the image quality setting at the time indicated by reference numeral 156.

  Eventually, the image quality exceeds the suspension upper limit 142 at the point of reference numeral 158. However, here, the image quality adjustment is not resumed at this point in order to maintain the fixed image quality setting as much as possible and prevent the flickering of the screen accompanying the adjustment. Subsequently, the error curve 140 exceeds the restart upper limit 146 at the point of reference numeral 160. However, considering the case where this event is caused by accidental image quality disturbance, the image quality adjustment is not resumed at this point. The image quality adjustment is resumed only at the point of reference numeral 162 that satisfies the condition that the resumption upper limit 146 is continuously exceeded for the time Δt.

  After the image quality adjustment is resumed, the error with respect to the target value of the image quality is rapidly improved, and is lower than the cancellation upper limit 142 at the time of reference numeral 164. Then, the image quality adjustment is fixed again at the time of reference numeral 166 when the convergence time Δt has elapsed from this time point.

  Note that when image quality adjustment is performed in this way, for example, when image enlargement / reduction switching or switching to an M-mode image is performed, image quality settings such as a preset gain and dynamic range are inherited. It is also effective.

It is a block diagram which shows the outline of the structural example of an ultrasonic diagnosing device. It is a flowchart which shows the flow of image quality evaluation. It is a figure explaining the example of an area | region division for image quality evaluation. It is a figure which shows the example of the histogram used for image quality evaluation. It is a flowchart which shows the flow of image quality adjustment. It is a figure which shows the example of correspondence of an image quality adjustment and an error.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Ultrasonic diagnostic apparatus, 12 Probe, 14 Transmitter, 16 Receiving amplifier, 18 Beam former, 20 Baseband signal processing part, 24 Display control part, 26 Display part, 28 Histogram processing part, 30 Gain dynamic range determination part, 32 Operation panel, 34 Operation analysis unit, 36 Database, 38 Timer, 42 Area division information, 44 Peak luminance representative value / luminance width representative value, 46 Gain setting / dynamic range setting, 100 scanning range, 102 depth direction, 104 scanning direction 106-122 Partial region.

Claims (8)

Ultrasonic image generating means for generating an ultrasonic image based on the received ultrasonic echo;
Image quality evaluation means for performing image quality evaluation on the generated ultrasonic image according to evaluation weights set non-uniformly for each region of the ultrasonic image;
Image quality adjusting means for adjusting the image quality of the ultrasonic image according to the result of the image quality evaluation;
Display means for displaying an ultrasonic image whose image quality has been adjusted;
An ultrasonic diagnostic apparatus comprising: The ultrasonic diagnostic apparatus according to claim 1,
The ultrasonic diagnostic apparatus, wherein the evaluation weight is set such that a partial region of the ultrasonic image is excluded from the evaluation target. The ultrasonic diagnostic apparatus according to claim 1,
The ultrasonic diagnostic apparatus, wherein the evaluation weight is set for each small region obtained by dividing all or part of the ultrasonic image into a plurality of parts. The ultrasonic diagnostic apparatus according to claim 1,
An ultrasonic diagnostic apparatus characterized in that image quality evaluation in image quality evaluation means is performed based on histogram analysis of echo intensity distribution. The ultrasonic diagnostic apparatus according to claim 1,
The ultrasonic diagnostic apparatus, wherein the image quality adjustment performed by the image quality adjustment means includes gain adjustment or dynamic range adjustment. The ultrasonic diagnostic apparatus according to claim 1,
The evaluation weight is set according to the diagnosis object or diagnosis method,
The ultrasonic diagnostic apparatus, wherein the image quality adjustment means adjusts the image quality so that a result of the image quality evaluation becomes a target image quality set according to a diagnosis target or a diagnosis method. The ultrasonic diagnostic apparatus according to claim 1,
The image quality adjustment in the image quality adjusting means is performed by excluding this region in the ultrasonic image when the image quality adjustment has already been performed on a partial region of the ultrasonic image by a user input. Ultrasonic diagnostic equipment. The ultrasonic diagnostic apparatus according to claim 1,
An ultrasonic diagnostic apparatus, wherein the ultrasonic image is a tomographic image.

Images