JP3322055B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly, to a configuration for converting received echo data, which is polar coordinate data, into rectangular coordinate data and writing display data to a memory address.

[0002]

2. Description of the Related Art Generally, an ultrasonic diagnostic apparatus for performing sector drive or convex drive is configured as shown in FIG. That is, the transmission circuit 2 transmits the driving pulse P to the ultrasonic probe 3 based on the trigger signal T generated by the control circuit 1. Ultrasonic probe 3 receiving drive pulse P
Transmits an ultrasonic wave to a subject (not shown). The transmitted ultrasonic wave is reflected by the subject, and the reflected wave is received by the ultrasonic probe 3. The received echo signals received by the ultrasonic probe 3 are sent from the ultrasonic probe 3 to the receiving circuit 4, and further, the phase of the received echo signals is adjusted by the phasing circuit 5. Thereafter, the signal is detected by the detection circuit 6. The detected received echo signal is A / D converted by an A / D converter 7 and then sent to a digital scan converter (hereinafter, referred to as DSC) 8. The DSC 8 converts the received echo signal, which is polar coordinate data, into rectangular coordinate data, stores display data at an address corresponding to the rectangular coordinate data, and transmits the display data to the display device 9.

Conventionally, such an ultrasonic diagnostic apparatus constructed as above, in the DSC 8, converts the polar coordinate data of the received wave echo signals A _n in the orthogonal coordinate addresses as follows, have entered the display data Was. That is, FIG.
As shown in (a) and (b), the threshold value N is set in advance in the Y direction (or X direction), which is one of the XY directions, in the rectangular coordinates. The threshold value N is usually set as an integral multiple of the address interval (lattice interval) of the orthogonal coordinates in that direction.

[0004] Then, based on the polar angle alpha _n received wave echo signals A _n input, XY direction component ratio of the received wave echo signals _{A n (sinα n, cosα n} : hereinafter, X direction conversion coefficient alpha _xn , Y-direction conversion coefficient _αyn ).

[0005] Sonouede, reception echo signal A pixel G _{n where n} constituting the (indicated by × mark in the drawing) and the ultrasonic probe 3
Distance data (hereinafter referred to as depth data) β _n ,
And calculates the Y direction component Y _n of each pixel G _n on the basis of the Y-direction conversion coefficient alpha _yn.

Then, the obtained Y-direction component Yn is _equal to the threshold N
Whether or not equal to an integral multiple, or it is judged whether or not the cross, when the judgment result is Yes, the depth data beta _n, X-direction conversion coefficient alpha _xn, and the Y-direction conversion coefficient alpha _yn
, The address position of the rectangular coordinates corresponding to the pixel _Gn is calculated. Then, by interpolating the display data gamma _n of the pixel G _n, written in the address position the display data gamma _n 'interpolated.

[0007]

However, in the conventional ultrasonic diagnostic apparatus for inputting the display data γ _n to the rectangular coordinate address in this manner, the loss of the pixel G _n increases as the polar angle α _n increases. In particular, in the vicinity of the maximum polar angle, there is a problem that the image quality is significantly reduced due to pixel loss, and the image becomes difficult to read.

That is, in the above-described conventional conversion configuration,
Each time the Y direction component Y _n exceeds an integer multiple of the threshold value N, the display data γ _n is interpolated and written to the orthogonal coordinate address. This is only the display data gamma _n pixel G _n immediately Y direction component Y _n exceeds the integral multiple of the threshold N is written to the corresponding address, the display data gamma _n pixel G _n the other is written Means no.

Therefore, the number of pixels that are not written fluctuates depending on the polar angle α _n , and as shown in FIG.
_{When n} is small, the number of pixels G _n that are not written for one address is small, and therefore, the number of pixels G _{n that} are lost is relatively small. On the other hand, as shown in FIG. 5B, when the polar angle α _n increases, the number of pixels G _n that are not written for one address also increases, and therefore, the number of pixels G _n lost also increases. More. Such pixel loss causes image quality deterioration near the maximum pole angle, and is very inconvenient.

Accordingly, it is an object of the present invention to reduce pixel loss and improve image quality.

[0011]

In order to achieve such an object, conventionally, a threshold value is set only in one direction (Y direction),
While the display data is written to the orthogonal coordinate address each time the one-directional component (Y-direction component) of the coordinate data of each pixel corresponding to the received echo signal exceeds this threshold, the present invention provides a method of X , Y direction, a threshold is set, and each time the X, Y component of the image data of the pixel exceeds these thresholds, the display data is written to the orthogonal coordinate address.

Specifically, reading means for reading the received echo signal, conversion means for converting polar coordinate data of each pixel corresponding to the read received echo signal into rectangular coordinate data, X direction component and Y
Comparing means for determining whether the direction component has become equal to or exceeding an integral multiple of a threshold value provided in each of the XY directions, and a logical sum of the X direction determination result and the Y direction determination result of the comparing means OR operation means for calculating
When the output of the OR operation means is true, the ultrasonic diagnostic apparatus is provided with writing means for writing display data to an address of a memory corresponding to the rectangular coordinate data.

[0013]

Each time the XY bidirectional components constituting the rectangular coordinate data obtained by converting the polar coordinate data of the pixel exceed the threshold values set in the respective XY directions, the display data is stored in the address position of the memory corresponding to the rectangular coordinate data. Is written, the number of pixels lost is reduced as compared with the case where the threshold is set in only one direction conventionally.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic diagnostic apparatus according to an embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a main part of the ultrasonic diagnostic apparatus according to the present embodiment.

The basic configuration of this ultrasonic diagnostic apparatus is shown in FIG.
The same or similar parts are denoted by the same reference numerals, and the description of the configuration and operation is omitted.

This ultrasonic diagnostic apparatus is characterized by the configuration of a DSC (digital scan converter) 10. That is, as shown in FIG.
, A conversion coefficient storage memory 12 and a rectangular coordinate conversion circuit 13
, A comparison circuit 14, an OR operation circuit 15, a display data interpolation circuit 16, a display address calculation circuit 17, a video memory 18, and a clock generator 19.

The input circuit 11 polar angle of the received wave echo signals A _n from the A / D conversion circuit 7 alpha _n, and reception echo signal A _n
Depth data beta _n of the pixel G _n corresponding is adapted to be fed. The polar angle α _n input to the input circuit 11 is output to the conversion coefficient storage memory 12, and the depth data β _n is output to the orthogonal coordinate calculation circuit 13, the display data interpolation circuit 16, and the display address calculation circuit 17, respectively. .

The conversion coefficient storage memory 12 stores an X-direction conversion coefficient α _xn (X-direction component ratio: sinα _n ) and a Y-direction conversion coefficient α _yn (Y-direction component ratio: cos α _n ) and inputs them. reception echo signal a based on the polar angle alpha _n of _n, the received wave echo signals a _n in the X-direction conversion coefficient alpha _xn, and the Y-direction conversion coefficient alpha orthogonal _yn coordinate transformation circuit 13, the display data interpolation circuit 16, And to the display address calculation circuit 17.

The orthogonal coordinate conversion circuit 13 converts the input transform coefficient alpha _xn, alpha _yn and depth data β and _n based on orthogonal polar coordinate data of the pixels G _n coordinate data (X _n, Y _n) in are doing. Specifically, while calculating the X-direction component X _n of the orthogonal coordinate data by the X-direction conversion coefficient alpha _xn and depth data beta _n, the orthogonal coordinate data by the Y-direction conversion coefficient alpha _yn and depth data beta _n of which calculates the Y direction component Y _n, the orthogonal coordinate data by converting this manner (X _n,
Y _n ) is output to the comparison circuit 14.

The comparison circuit 14 receives rectangular coordinate data (X _n , Y _n ), and also stores a threshold M along the X direction and a threshold N along the Y direction stored in a storage unit (not shown).
(Each of the thresholds M and N is usually set to an integral multiple of the address interval (lattice interval) of the rectangular coordinates. The comparison circuit 14 inputs the X-direction component X based on these input data. _n ≧ (an integral multiple of the threshold M), compared Y direction component Y _n ≧ the became whether (an integer multiple of the threshold n), respectively, and outputs the result to the logical oR operation circuit 15.

The OR operation circuit 15 performs an OR operation on the basis of the comparison result input from the comparison circuit 14 and outputs the result to the video memory 18.

The display data interpolation circuit 16 includes depth data β _n , an X-direction conversion coefficient α _xn , and a Y-direction conversion coefficient α _yn , and display data γ _n , γ of adjacent pixels G _n , G _{n-1. n-1} is input. The display data interpolation circuit 16 interpolates the display data γ _n−1 and γ _n based on these input data by an interpolation method described later, and stores the interpolated data γ _n x ′ (γ _n y ′) in the video memory 18. Output to

The display address calculating circuit 17, the depth data beta _n, X-direction conversion coefficient alpha _xn pixel G _n, based on the Y-direction conversion coefficient alpha _yn, orthogonal coordinate to be input to the display data of each pixel G _n Is calculated and output to the video memory 18.

The video memory 18 has a storage unit having an address to which display data of each pixel _Gn is written.

The clock generator 19 outputs a clock signal for controlling the operation of each circuit described above.

In this embodiment, the input circuit 11 constitutes reading means, the transform coefficient storage memory 12 and the orthogonal coordinate transforming circuit 13 constitute transforming means, and the comparing circuit 14 constitutes comparing means. The display data interpolating circuit 16 is composed of the OR operation circuit and the OR operation means.
Writing means is composed of the display address calculating circuit 17 and the display address calculating circuit 17.

Next, an operation of writing data into the video memory 18 by the ultrasonic diagnostic apparatus will be described with reference to FIG.
Here, polar angle alpha ₁ is relatively large, in the conventional structure, illustrating a state in which a receive echo signals A ₁ which increases the number of lost pixels and reception. In this DSC 10, the threshold M
Is the X-direction address interval (lattice interval) of the rectangular coordinate address
And the threshold value N is also set to Y of the rectangular coordinate address.
The same as the direction address interval (grid interval).
Then, for convenience of explanation, integer multiple positions (grid positions) of the threshold value M are described as 1M, 2M, 3M,...
In addition, the integer multiple positions (grid positions) of the threshold value N are described as 1N, 2N, 3N,.

When the pixel G _n of the received echo signal A ₁ is input, the orthogonal coordinate conversion circuit 13 outputs the depth data β of the pixel G _n input from the A / D conversion circuit 7 via the input circuit 11. _n
If, converting received wave echo signals A ₁ of the transform coefficients alpha _x1 input from the coefficient storage memory 12, based on the alpha _y1, converts the polar coordinates of the pixel G _n orthogonal coordinate (X _n, Y _n) in the. Then, each of the converted directional components X _n , Y _n of the orthogonal coordinates (X _n , Y _n ) is compared with an integer multiple of the threshold values M and N in the comparison circuit 14.

In the case of a pixel G _{1 having} rectangular coordinates (X ₁ , Y ₁ ), X ₁ ≧ (integral multiple of threshold M 2M) and Y ₁ <(integral multiple of threshold N 2N). The output of circuit 15 is true. Therefore, the display data interpolation circuit 16
_The interpolation data γ ₁ ′ obtained by interpolating the display data γ ₁ of 1 is written into the address position (2M, 1N) of the video memory 18 calculated by the display address calculation circuit 17.

In the case of a pixel G _{2 having} rectangular coordinates (X ₂ , Y ₂ ), since X ₂ <(3M of integral multiple of threshold M) and Y ₂ <(2N of integral multiple of threshold N), a logical sum operation is performed. The output of circuit 15 is not true. Therefore, the display data gamma ₂ pixel G ₂ is not written into the video memory 18.

In the case of the pixel G _{3 having} the rectangular coordinates (X ₃ , Y ₃ ), since X ₃ <(integral multiple of the threshold M: 3M) and Y ₃ ≧ (integer multiple of the threshold N: 2N), the logical sum operation is performed. The output of circuit 15 is true. Therefore, the display data interpolation circuit 16
_The interpolation data γ ₃ ′ obtained by interpolating the _third display data γ ₃ is written to the address position (2M, 2N) of the video memory 18 calculated by the display address calculation circuit 17.

In the case of the pixel G _{4 having} rectangular coordinates (X ₄ , Y ₄ ), since X ₄ ≧ (3M of integral multiple of threshold M) and Y ₄ <(3N of integral multiple of threshold N), a logical sum operation is performed. The output of circuit 15 is not true. Therefore, the display data gamma ₄ pixels G ₄ are not written in the video memory 18.

As described above, each time the rectangular coordinates (X _n , Y _n ) of each pixel G _n exceed the integral multiple of the threshold values M and N provided in the X and Y directions, a predetermined display address position is set. since the display data gamma data obtained by interpolating the _{n γ n x '(γ n} y') is written to, so that the number of pixels loss is reduced. Incidentally, X-direction, Y-direction at the same time the display data gamma _n x '
If the logical sum operation circuit 15 makes a decision to write (γ _n y ′), if the writing operation in one direction (for example, the Y direction) is prioritized, confusion in data writing does not occur. .

Next, an operation of interpolating display data by the display data interpolation circuit 16 will be described. First, an interpolation operation along the X direction, that is, an interpolation operation when pixels G _n and G _n−1 are arranged across an X direction grid (an integer multiple of a threshold value) as shown in FIG. Will be described.

The pixel G _n and the immediately preceding pixel G _n−1 are obtained at every X-direction echo sampling interval Xp of the ultrasonic wave and at every depth interval (β _n −β _n-1 ). Therefore, the pixel G _n
And X-direction grid (threshold) 1M line located between the G _n-1,
2M lines, ... when writing display data on the line, the pixel G _n 'display data gamma _n x' of writing are interpolated as the following equation.

The _{γ n x '= [γ n} (Xp-m) + γ n-1 · m] / Xp ... γ n x': interpolated with X-direction grid (threshold) 1M line, 2M
Line, display data written on the line γ _n : display data of pixel G _n γ _n-1 : display data of pixel G _n-1 Xp: echo sampling interval m: pixel G _n and X-direction grid (threshold) 1M line , 2M line, ...
The interpolation operation along the Y direction, that is, as shown in FIG. 3B, the pixels G _n and G _n-1 are arranged in a Y direction grid (threshold) 1N line,
A description will be given of an interpolation operation in the case of arranging over 2N lines,.

The pixel G _n and the immediately preceding pixel G _n−1 are obtained at every ultrasonic Y-direction echo sampling interval Yp and at every depth interval (β _n −β _n-1 ). Therefore, the pixel G _n
And Y-direction grid (threshold) 1N line located between the G _n-1,
When the display data is written on the 2N line,... Line, the display data γ _n y ′ of the pixel G _n ′ to be written is interpolated as in the following equation.

Γ _n y ′ = [γ _n (Yp−n) + γ _n−1 · n] / Yp... Γ _n y ′: Interpolated and Y direction grid (threshold) 1N line, 2N
Line, display data written on the line γ _n : display data of pixel G _n γ _n-1 : display data of pixel G _n-1 Yp: echo sampling interval n: pixel G _n and Y direction grid (threshold) 1N line , 2N line, ...
In the above embodiment, the threshold _values M and N are provided in the X and Y directions, respectively, and each time the X and Y components of the orthogonal coordinate data of the pixel _Gn exceed the threshold _values M and N, the pixel G _n
Although the display data is written to the address corresponding to the above, thereby reducing the pixel loss, the following configuration may be adopted.

That is, reading means for reading the received echo signal, conversion means for converting the polar coordinate data of each pixel corresponding to the read received echo signal into rectangular coordinate data, polar angle of the read received echo signal, Angle comparing means for comparing with an arbitrary angle set in advance, and when the output of the comparing means is (polar angle <optional angle), one direction component of the orthogonal coordinate data is provided in this direction. While it is determined whether the output value of the comparison means is (polar angle> arbitrary angle) while the output of the comparison means is equal to or greater than an integer multiple of the threshold value, the other direction component of the orthogonal coordinate data is: A determining means for determining whether or not an integer multiple of a threshold value provided in this direction, or whether or not exceeding the threshold value, wherein the determining means determines that the orthogonal coordinate component is larger than the threshold value; The writing means for writing the orthogonal coordinate display data to the address of the memory corresponding to the data, constituting the ultrasonic diagnostic apparatus includes a depending on an output of the comparing means.

Specifically, this ultrasonic diagnostic apparatus is a DSC
(Digital Scan Converter) 20 is characterized by the configuration. That is, as shown in FIG. 4, the DSC 20 includes an input circuit 11, a conversion coefficient storage memory 12, a rectangular coordinate conversion circuit 13, a comparison circuit 14, a display data interpolation circuit 16, a display address calculation circuit 17, Memory 1
8 and a clock generator 19, an angle comparison circuit 21 and a selection circuit 22. Note that the input circuit 11, the conversion coefficient storage memory 12, the orthogonal coordinate conversion circuit 1
3, the configuration of the comparison circuit 14, the display data interpolation circuit 16, the display address calculation circuit 17, the video memory 18, and the clock generator 19 are the same as those of the above-described embodiment, and therefore the description thereof is omitted.

The angle comparison circuit 21 except that is from the input circuit 11 as polar angle alpha _n of each wave receiving echo signals A _n are input, preset arbitrary angle B (for example, 45 °)
When the input pole angle α _n <arbitrary angle B, the selection signal S1 is output to the determination circuit 22. On the other hand, when the input pole angle α _n > arbitrary angle B, Outputs the selection signal S2 to the determination circuit 22.

The judging circuit 22, while the selection signal S1 is input, to monitor the comparison result of the Y-direction in the comparison circuit 14, the comparison result (pixel G _n Y direction component Y _n of the orthogonal coordinate data ) ≧ (an integer multiple of the threshold value N in the Y direction), a signal for permitting writing to the video memory 18 is output.

The judgment circuit 22 monitors the comparison result in the X direction by the comparison circuit 14 while the selection signal S2 is being input, and the comparison result indicates (the X direction component of the orthogonal coordinate data of the pixel _Gn ). When (X _n ) ≧ (an integer multiple of the threshold value M in the X direction), a signal that permits writing to the video memory 18 is output.

The video memory 18, based on the permission signal of the decision circuit 22, the address position calculated display address calculating circuit 17, the data gamma _n x interpolated display data in the display data interpolation circuit 16 '(γ _n y' Write).

When the DSC 20 is configured as described above,
For polar angle alpha _n is small reception echo signal A _n, less the threshold comparison method of pixel loss, i.e., Y-direction threshold N and Y
While determining the write pixel by comparing the direction component Y _n, in the case of reception echo signal A _n polar angle alpha _n is large, a small threshold comparison method of pixel loss, i.e., X-direction threshold M
And the X direction component _Xn are compared to determine pixel writing. That is, by selecting the threshold comparison method according to the magnitude of the polar angle α _n , the pixel loss is reduced, and the image quality is prevented from deteriorating.

[0046]

As described above, according to the present invention, each time the XY bidirectional components of the orthogonal coordinate data obtained by converting the polar coordinate data of the pixel exceed the threshold values set in the XY directions, the rectangular coordinate data is converted to the orthogonal coordinate data. Since the display data is written in the corresponding memory address position, the number of lost pixels is reduced as compared with the case where the threshold value is set in only one direction in the related art. For this reason, it was possible to prevent the image quality from being reduced due to such pixel loss, and particularly to improve the image quality near the maximum pole angle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an ultrasonic diagnostic apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a pixel writing operation in the ultrasonic diagnostic apparatus according to the embodiment.

FIG. 3 is a diagram illustrating an interpolation operation.

FIG. 4 is a block diagram illustrating a main part of an ultrasonic diagnostic apparatus according to another embodiment.

FIG. 5 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 6 is a diagram illustrating a pixel writing operation of a conventional ultrasonic diagnostic apparatus.

[Explanation of symbols]

 Reference Signs List 11 input circuit 13 orthogonal coordinate conversion circuit 14 comparison circuit 15 OR operation circuit 17 display data interpolation circuit 18 video memory

Claims (1)

(57) [Claims] A reading means for reading a received echo signal; a converting means for converting polar coordinate data of each pixel corresponding to the read received echo signal into rectangular coordinate data; an X-direction component of the converted rectangular coordinate data; Comparing means for determining whether or not the Y-direction component has become equal to or greater than an integral multiple of a threshold value provided in each of the XY directions; and a logic of the X-direction determination result and the Y-direction determination result of the comparison means. OR operation means for calculating a sum, and writing means for writing display data to an address of a memory corresponding to the rectangular coordinate data when an output of the OR operation means is true. Ultrasound diagnostic equipment.