JP2000139914A - Ultrasonograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To locally adjust luminance separately from the whole image and to realize an overall observation and a local observation by adjusting the luminance in a concerned region when the concerned region is set at the desired position on the ultrasonic image. SOLUTION: A region of interest(ROI) setter 17 is a means used by a user to set an ROI, and it is formed with a rack ball or a mouse. The coordinate information 102 indicating the outer frame of the set ROI is outputted to a region discriminator 24. The region discriminator 24 judges the luminance information with the coordinate information 102 of the ROI used as a reference, outputs the adjustment curve set by a first luminance adjustment curve setter 32 to a luminance regulator 26 as adjustment information when the luminance information is from within the ROI, and outputs the adjustment curve set to a second luminance adjustment curve setter 34 when the luminance information is from outside the ROI. The luminance regulator 26 makes a luminance adjustment, i.e., a gain adjustment, and a contrast adjustment according to the luminance adjustment curve set by the region discriminator 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to adjustment of luminance (contrast and gain).

[0002]

2. Description of the Related Art A received signal (echo data) obtained by transmitting and receiving an ultrasonic wave includes weak amplitude information to large amplitude information, that is, the dynamic range of the received signal is extremely wide. For this reason, in a general ultrasonic diagnostic apparatus, a process of forming an ultrasonic image (for example, a B-mode image) with the amplitude corresponding to the luminance is performed after the received signal is logarithmically converted and compressed. Typically,
The number of gradations in the display is about 256 gradations (8 bits), and the range is significantly narrower than the dynamic range of the received signal. Therefore, in an actual ultrasonic diagnostic apparatus, a device has been devised so that all signal components fall within the display gradation by performing non-linear conversion in addition to logarithmic conversion.

[0003] Because of the above-mentioned restrictions, if priority is given to the overall image quality, it is difficult to observe a portion where there is not much difference in luminance. Conversely, contrast is enhanced so as to emphasize the difference in luminance of the portion. If this is changed, problems such as saturation of the high-brightness portion occur. When observing an ultrasonic image, there may be a case where it is desired to observe the image locally while observing the entire image, and an apparatus that can form an image that meets both observation requirements is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to superimpose luminance by locally adjusting the brightness separately from the entire image, thereby realizing excellent overall observation and local observation. It is to provide an ultrasonic diagnostic apparatus.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a transmitting / receiving means for transmitting / receiving ultrasonic waves, and forms an ultrasonic image based on a signal received from the transmitting / receiving means. An image forming unit, a region-of-interest designating unit for locally designating a region of interest on the ultrasonic image, and a region-of-interest adjusting unit that independently adjusts luminance of the region of interest. And

According to the above configuration, when the region of interest is set at a desired position on the ultrasonic image, the brightness in the region of interest is adjusted by the region-of-interest adjusting means. That is, a gain and a contrast different from those of other regions can be set only for the region of interest. Therefore, a special gain and contrast can be set only for the region of interest without breaking the gain and contrast of the entire image. Therefore, according to the present invention, a portion having a small luminance difference can be emphasized and expressed, and an image useful for disease diagnosis can be constructed.

[0007] The above-mentioned region-of-interest adjustment means can be provided at various locations on the path for processing the received signal, and adjustment is performed according to the location. For example, it can be arranged in various places such as in a receiving circuit, after quadrature detection, after amplitude calculation, and in DSC.

The region of interest is basically set manually, but may be set automatically in some cases. Also, the brightness adjustment in the region of interest may be performed after the brightness adjustment of the entire image, or the brightness adjustment in the region of interest and the brightness adjustment outside the region of interest may be performed independently and in parallel. Is also good.

Preferably, the apparatus further includes input means for designating a brightness adjustment curve of the in-region-of-interest adjustment means. According to this configuration, for example, the contrast and the gain can be freely adjusted while viewing an actual image or the like. The brightness adjustment curve corresponds to a brightness conversion table or the like.

Preferably, the apparatus further comprises a histogram display means for displaying a luminance histogram in the region of interest. According to this configuration, the brightness adjustment curve can be changed manually or automatically while viewing or using the histogram.

Preferably, the apparatus further includes evaluation calculating means for calculating evaluation information on the region of interest, and characteristic setting means for setting a brightness adjustment curve of the adjusting means in the region of interest based on the evaluation information. According to the automatic setting of the brightness adjustment curve, there is an advantage that the complexity associated with the manual setting can be eliminated and that the present invention is also effective for a moving image.

The evaluation information is, for example, statistical information such as average luminance, mode (mode), median (median), maximum, minimum, and standard deviation in the region of interest, or information obtained therefrom. . For example, the maximum value in the region of interest may be set to the maximum of the luminance range, and the minimum value may be set to the minimum of the luminance range, or N × standard deviation may be set on both sides of the most frequent or average value. May be set as an ideal luminance distribution (however, N is a user-specified value).

Preferably, the adjustment curve changing means for sequentially changing the brightness adjustment curve in the in-region-of-interest adjustment means, the evaluation calculation means for calculating evaluation information for the area of interest for each of the brightness adjustment curves, Optimal curve determining means for comparing the evaluation information for each adjustment curve to determine an optimal curve, wherein the optimal curve is set in the in-region-of-interest adjusting means.

According to the above configuration, the optimum curve can be automatically determined by trially changing the brightness adjustment curve and evaluating each brightness adjustment curve. In this case, the trial change of the adjustment curve is automatically started at a fixed period or automatically when a predetermined condition is satisfied.
Of course, the change of the adjustment curve may be executed by a user's instruction.

According to another aspect of the present invention, there is provided a transmitting / receiving means for transmitting / receiving ultrasonic waves, and an image forming means for forming an ultrasonic image based on a reception signal from the transmitting / receiving means. A region-of-interest designation unit for designating a region of interest on the ultrasonic image, a reference region designation unit for designating a reference region on the ultrasonic image, and statistical information about the region of interest and the reference region And an evaluation calculating means for calculating evaluation information from the information processing apparatus, and an in-region-of-interest adjusting means for adjusting the brightness of the region of interest based on the evaluation information.

According to the above configuration, a reference region is set in addition to the region of interest, and the luminance of the region of interest is adjusted in comparison with the reference region. In this case, the reference area is set manually or automatically according to the method to be compared.

According to another aspect of the present invention, there is provided a transmitting / receiving means for transmitting / receiving an ultrasonic wave, and an image forming means for forming an ultrasonic image based on a reception signal from the transmitting / receiving means. A region-of-interest designating unit for designating a region of interest on the ultrasonic image; a normal region outside the region of interest on the ultrasonic image; a region-of-interest adjusting unit for adjusting luminance; And an in-region-of-interest adjustment means for adjusting the luminance of the region of interest in the above-mentioned region, and the luminance can be adjusted independently inside and outside the region of interest.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an ultrasonic image 200 and a brightness adjustment curve. In the display example shown in (A), an ultrasonic image 200 obtained by sector scanning is formed.

On the ultrasonic image 200, a region of interest (ROI) 202 is provided at an arbitrary position in a desired shape by a user.
Is set. In FIG. 1, ROI 202 is shown as a rectangular area, but this area may be a circular area or an elliptical area. The ROI 202 functions as a magnifying glass or a viewing window for enhancing brightness, and can individually adjust gain and contrast only in the ROI 202. That is, the brightness adjustment can be performed independently on the ROI 202 separately from the brightness adjustment on the entire ultrasonic image 200. (B) shows an example of a brightness adjustment curve for the entire ultrasonic image 200, and (C) shows an ROI 20.
Some examples of brightness adjustment curves within 2 are shown. Each curve as shown in (B) and (C) can be manually designated or automatically set.

The reference area 204 shown in FIG. 2A is an area used supplementarily in evaluating a brightness adjustment curve as described later. This will be described later in detail.

Therefore, according to the embodiment shown in FIG. 1, the contrast and the like can be emphasized only for a portion to be focused on without deteriorating the gain and contrast of the entire ultrasonic image. A boundary or the like can be clearly displayed as an image.

FIG. 2 is a block diagram showing a preferred embodiment of the ultrasonic diagnostic apparatus according to the present invention.

In FIG. 2, a probe 10 is an ultrasonic probe for transmitting and receiving ultrasonic waves. The probe 10 is used in contact with the body surface or inserted into a body cavity.

The transceiver 12 is a circuit that supplies a transmission signal to the probe 10 and performs processing such as amplification on the reception signal output from the probe 10. The reception beamformer 15 forms a reception beam from the amplified reception signal. The transmission beam is scanned by the transceiver 12.
Is controlled by the transmission beamformer 14 connected to the. The timing signal generator 16 performs timing control and operation control on each circuit including the transmission beamformer 14.

The ROI setting unit 17 is means for setting an ROI as a region of interest by a user, and is constituted by, for example, a trackball or a mouse.

In this embodiment, the ROI is set manually, but it is of course possible to configure the ROI automatically. The coordinate information 102 representing the outer frame of the set ROI is output to the area discriminator 24 described later.

The quadrature detector 18 is a circuit that performs quadrature detection on the received signal output from the transceiver 12. The quadrature detector 18 is a known circuit.

The complex signal generated by the quadrature detector 18 is sent to an amplitude calculator 20, from which an envelope of amplitude information is obtained. The signal is sent to the brightness adjustment unit 22 as brightness information.

In the configuration example shown in FIG. 2, various existing luminance adjustment units such as a logarithmic converter and a non-linear converter are not shown. The brightness adjustment unit 22 is a unit that performs brightness adjustment together with or separately from those components.

In the brightness adjustment section 22, an area discriminator 24
Determines whether the input luminance information is within the ROI or outside the ROI. The area determination is performed based on the position information 100 of the received signal output from the timing signal generator 16. That is, based on the ROI coordinate information 102, the area discriminator 24 performs the adjustment adjustment set by the first luminance adjustment curve setting unit 32 when the luminance information is from within the ROI, while If it is outside the ROI, the adjustment curve set by the second brightness adjustment curve setter 34 is sent to the brightness adjuster 26 as adjustment information. Further, the area discriminator 24 creates a flag indicating whether the luminance information is from within the ROI or from outside the ROI, and sends the flag to the evaluation unit 36 and the histogram creator 42. Incidentally, the brightness adjustment unit 22 can be configured by hardware or software.

The brightness adjuster 26 is a circuit for performing brightness adjustment, that is, gain adjustment and contrast adjustment in accordance with the brightness adjustment curve set by the area discriminator 24. Since the brightness can be adjusted independently inside and outside the ROI, FIG. Can be realized.

Here, the brightness adjustment curve setting unit 30 includes a first brightness adjustment curve setter 32 and a second brightness adjustment curve setter 34.
, And a user can set a brightness adjustment curve inside and outside the region of interest by using these setting devices. The brightness adjustment curve designated by the first brightness adjustment curve setting unit 32 is input to the brightness adjustment unit 26 via the area discriminator 24. Note that an AGC (auto gain control) signal is also input to the brightness adjuster 26, so that brightness adjustment similar to that of an existing ultrasonic diagnostic apparatus can be performed as needed.

The brightness adjustment curve setting unit 30 includes a brightness adjuster 2
It is also possible to automatically set the brightness adjustment curve in 6. In the present embodiment, the brightness adjustment curve is automatically set based on the brightness distribution in the ROI, or the brightness adjustment curve is automatically set by executing an automatic adjustment curve variable function described later. The brightness adjustment curve thus set is sent to the brightness adjuster 26 via the area discriminator 24, and as described above, the brightness adjuster 26 adjusts the brightness according to the brightness adjustment curve thus set. Execute.

The luminance information output from the luminance adjuster 26 is input to a DSC (Digital Scan Converter) 44. The DSC 44 has, for example, a coordinate conversion function and an interpolation function, and a tomographic image such as a B-mode image is formed in a frame memory provided in the DSC 44. Then, the image is displayed on the display 46.
On the other hand, in the histogram creator 42, only the luminance information in the ROI is selected by the flag from the area discriminator 24 to create a histogram. The histogram is also displayed on the display 46 via the DSC.

Thus, the user can freely set the brightness adjustment curve for the region of interest based on the displayed histogram.

The evaluation section 36 is means for calculating one or a plurality of statistical information as evaluation information based on the luminance information in the region of interest. The statistical information is, for example, information such as average brightness, mode (mode), median (median), maximum and minimum values, and standard deviation in the region of interest. The information is processed as it is or is processed by the brightness adjustment curve setting unit 30.
The brightness adjustment curve setting unit 30 performs automatic setting of the brightness adjustment curve for the region of interest using the statistical information. For example, the maximum value in the region of interest is set to the maximum in the luminance range, and the minimum value in the region of interest is set to the minimum in the luminance range. Alternatively, an ideal distribution having a width of N × standard deviation above and below the mode or the average is assumed, and the contrast is adjusted according to such a distribution.

In this embodiment, the brightness adjustment curve setting section 30 has an automatic adjustment curve variable function. That is, the brightness adjustment curve is gradually variably set, and based on the evaluation result of the evaluation unit 36 in that case, the curve that finally has the best evaluation result is determined as the optimum curve. Then, the determined brightness adjustment curve is set in the brightness adjuster 26 via the area determiner 24. In this case, various methods can be considered as the evaluation method in the evaluation unit 36.

For example, in the present embodiment, a curve having the highest evaluation value as defined by the following equation (1) or (2) is determined as the optimal curve.

[0040]

(Equation 1) In the above formula, the target corresponds to the region of interest, and the background corresponds to the reference region 204 shown in FIG. 1, and generally designates a portion having the lowest luminance such as the heart chamber. The reference region 204 is set in a different region from the region of interest 202. In setting the reference area 204, the ROI setting unit 17 and the like are used together.

Of course, various evaluation values can be used, and the above formula is an example.

FIG. 3 shows a setting example regarding optimization of the luminance range. (A) shows a histogram of luminance information input to the luminance adjuster 26, and (B) shows a histogram after luminance adjustment. In this example, the minimum luminance value A is set to the minimum in the luminance range, and the maximum luminance value B is set to the maximum in the luminance range. By expanding the luminance display range in this way, it is possible to highlight a portion where the luminance difference is small.

[0043]

As described above, according to the present invention,
Brightness can be adjusted locally separately from the entire image,
Good overall observation and local observation can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining the principle of the present invention.

FIG. 2 is a block diagram of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 3 is a diagram illustrating a setting example regarding optimization of a luminance range.

[Explanation of symbols]

Reference Signs List 10 probe, 12 transceiver, 14 transmit beamformer, 15 receive beamformer, 16 timing signal generator, 17 ROI setting device, 18 quadrature detector, 20
Amplitude calculator, 22 brightness adjuster, 24 area discriminator,
26 brightness adjuster, 30 brightness adjustment curve setting unit, 32
First brightness adjustment curve setting device, 34 Second brightness adjustment curve setting device, 36 Evaluator, 42 Histogram creator.

Continued on the front page F term (reference) 4C301 AA01 BB02 CC02 EE20 FF01 HH52 HH54 JB11 JB12 JC20 KK04 KK30 KK40 LL04 5B057 AA07 BA05 BA24 BA25 CC03 CE11 5J083 AA02 AB17 AC29 AD13 AE08 BD02 BE11 BE14 EBEA BE48

Claims (7)

[Claims] A transmitting / receiving means for transmitting / receiving an ultrasonic wave; an image forming means for forming an ultrasonic image based on a reception signal from the transmitting / receiving means; and a region of interest locally on the ultrasonic image. An ultrasound diagnostic apparatus comprising: a region of interest designating unit for designating; and an in-region-of-interest adjusting unit that independently adjusts luminance of the region of interest. 2. The ultrasonic diagnostic apparatus according to claim 1, further comprising input means for designating a brightness adjustment curve of said in-region-of-interest adjustment means. 3. The ultrasonic diagnostic apparatus according to claim 1, further comprising a histogram display unit for displaying a luminance histogram in the region of interest. 4. The apparatus according to claim 1, wherein: an evaluation calculating unit configured to calculate evaluation information on the region of interest; and a brightness adjustment curve of the adjustment unit in the region of interest based on the evaluation information. An ultrasonic diagnostic apparatus, comprising: curve setting means for setting the following. 5. The apparatus according to claim 1, wherein: an adjustment curve changing unit that sequentially changes a brightness adjustment curve in the in-region-of-interest adjustment unit; and for the region of interest for each of the brightness adjustment curves. Evaluation calculation means for calculating the evaluation information, and optimal curve determination means for mutually comparing the evaluation information for each of the brightness adjustment curves to determine an optimal curve. An ultrasonic diagnostic apparatus, wherein a curve is set. 6. A transmitting / receiving unit for transmitting / receiving an ultrasonic wave, an image forming unit for forming an ultrasonic image based on a reception signal from the transmitting / receiving unit, and specifying a region of interest on the ultrasonic image. A region-of-interest designation unit for designating, a reference region designation unit for designating a reference region on the ultrasound image, an evaluation computation unit that computes evaluation information from statistical information about the region of interest and the reference region, An intra-region-of-interest adjusting means for adjusting the luminance of the region of interest based on the evaluation information. 7. A transmitting / receiving means for transmitting / receiving an ultrasonic wave; an image forming means for forming an ultrasonic image based on a reception signal from the transmitting / receiving means; and specifying a region of interest on the ultrasonic image. A region-of-interest specifying means for adjusting the brightness of a normal region outside the region of interest on the ultrasonic image; and a region of interest adjusting the luminance of the region of interest on the ultrasonic image. An ultrasonic diagnostic apparatus, comprising: an inner adjustment unit, wherein brightness can be independently adjusted inside and outside the region of interest.