JPH08308838A - Ultrasonographic diagnostic device - Google Patents

Abstract

PURPOSE: To provide a good tomographic image of an organ whose echo level is relatively low. CONSTITUTION: An echo signal received by an ultrasonic probe 1 is detected/ processed as an analogue signal by means of a front end(F/E) part 2, and is displayed on a monitor 10 after image-processed by means of a digital scan converter(DSC) 11, and the echo signal of low to medium level can be expressed with high resolution, by providing with a data converter 4 between an A/D converter 3 inside the DSC 11 and a frame correlated processing circuit 5, and with a data converter 8 between an interpolation processing circuit 7 and a D/A converter 9, respectively.

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 an ultrasonic diagnostic apparatus capable of obtaining a good tomographic image even for an organ such as a liver having a relatively low echo level.

[0002]

2. Description of the Related Art Conventionally, in a digital scan converter (DSC) of an ultrasonic diagnostic apparatus, the capacity of an image memory for one pixel (pixel) of a display image is made to match the resolution of an analog / digital (A / D) converter. I have to. For example, for a 6-bit A / D converter, the capacity of the image memory is 6 bits / pixel. This means that when an image memory having an 8-bit / pixel structure is used to display information other than the image by overlaying it on the tomographic image (for example, M cursor: a cursor for indicating the collection position of M mode image data). This is convenient because the utilization efficiency of the hardware memory is increased.

[0003]

However, in the ultrasonic diagnostic apparatus having such a configuration, the A / D is used for the purpose of obtaining an image quality with high luminance resolution in low to medium luminance (low to medium gradation portion) in the image. If the resolution of the converter is increased to, for example, 8 bits, the memory capacity increases, the frame correlation processing circuit and the interpolation processing circuit become complicated, and the cost performance deteriorates. Therefore, an object of the present invention is to improve the image quality in the low-to-medium luminance portion by using a high resolution A / D converter without complicating the configuration.

[0004]

In order to solve such a problem, in the invention of claim 1, an ultrasonic probe, a front end portion including an echo signal detection circuit, and an analog / analog echo signal with a resolution of K bits are used. A / D converter for digital conversion, image memory for storing images with N bits per pixel (K> N), and D / A for converting output from the image memory into analog quantity after predetermined processing In an ultrasonic diagnostic apparatus comprising a digital scan converter including a converter and a display monitor, first data conversion means for converting K bit data into N bit data between the A / D converter and an image memory. And the image memory and the D /
A second data conversion means for returning N-bit data to K-bit data is provided between the A converter and the A converter.

In the invention of claim 1, the address is x (bit) and the data is y as the first data conversion means.
Constituted by a ROM (bits), and the relationship between the address x and the data y ^{is, x ≒ (r y -1)} / (r-1)
However, r = 1.0385. Can be an integer satisfying the following relation (invention of claim 2), and a plurality of the first data conversion means are provided, and can be selected according to the sense of the person observing through the display monitor. (The invention of claim 3).

[0006]

The first data converter represents low-to-medium level echo signals with high resolution, the high-level echo signal represents low resolution, and the second data converter restores the number of bits. Thus, low-to-medium level echo signals can be expressed with good image quality in which gradations are finely divided. The first and second data converters are read-only memories (RO
M) can be easily configured, and in particular, by appropriately selecting the input / output relationship, low-to-medium level echo signals can be expressed with high resolution. Further, a plurality of the first data conversion means are provided to enable selection according to the sense of the observer, and the diagnosis is effectively performed.

[0007]

1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 1 is an ultrasonic probe, 2 is a front end section (F / E section), 3 is an analog / digital (A
/ D) converter, 4 and 8 are data converters, 5 is a frame correlation processing circuit, 6 is an image memory, 7 is an interpolation processing circuit, 9 is a digital / analog (D / A) converter, and 10 is a display monitor. , 11 are DSCs.

That is, the reflected wave (echo signal) of the ultrasonic wave received by the ultrasonic probe 1 is detected and processed as an analog signal by the F / E section 2 and converted into a digital signal by the A / D converter 3. It is stored in the image memory 6. Image data is read from the image memory 6 in synchronization with the horizontal and vertical signals of the television system, converted into an analog signal by the D / A converter 9, and then displayed as a tomographic image on the display monitor 10. It

Further, in this embodiment, the A / D converter 3
The first data converter 4 is provided in the subsequent stage and in the preceding stage of the frame correlation processing circuit 5, and D / is provided in the subsequent stage of the image memory 6.
The second data converter 8 is provided in front of the A converter 9. Here, the resolution of each of the A / D converter 3 and the D / A converter 9 is 8 bits, and the bit allocation number per pixel of the image memory 6 is 6. Therefore, the former stage of the data converter 4 and the latter stage of the data converter 8 are composed of 8 bits, and the image memory 6 and the interpolation processing circuit 7 are composed of 6 bits. That is, since a general image memory has a bit configuration that is an integral multiple of 4, if an image memory with an 8-bit configuration is used here, the remaining 2 bits of the 6 bits allocated for the image are used for storing other information. Can be used as.

As the first data converter 4, for example, a read only memory (ROM) is used to convert an 8-bit input (D1) into a 6-bit output (D2) as shown in FIG. As shown by the solid line in FIG. 2, in an area where the input x is small, the increase of y is “1/63 of the maximum value of y” for the increase of “1/255 of the maximum value” of x, but x increases. According to the above, the increase of y is about 1/63 of the maximum value of y for the increase of 2/255 of the maximum value of x,
255 "increase of y is 1 / maximum value of y
63 ", ... x" 8/255 of maximum value "," 9 of maximum value "
/ 255 "," maximum value of 10/255 "... Increase of y is as" 1/63 of maximum value of y ". This means that low to medium level echo signals
It is shown that it can be expressed with a resolution of 2/255, 3/255 ... If the resolution of the A / D converter 3 is 6 bits, as shown by the dotted line in FIG. 2, the increase in y is equal to the "maximum value of 1/63" of x in the entire area of the input x. 1/63 of the value, and the echo signal is 1/63
It cannot be expressed with a resolution exceeding.

As an example of conversion characteristics for converting an 8-bit input into a 6-bit output, one shown in FIG. 3 can be considered. This inputs the x, the output as y, it is an integer satisfying ^{x ≒ (r y -1) /} (r-1) the relationship. However, r =
It is calculated as 1.0385.

As the second data converter 8, for example, RO
M can be used, and as shown in FIG. 4, a 6-bit input (D4) is converted to an 8-bit output (D5), that is, data conversion reverse to that of the first data converter 4 is performed. That is,
With respect to the amount of change of y with respect to the change of x in the small input x region, y with respect to the change of x in the large x region
The amount of change in is markedly larger. As a result, the low-to-medium level echo signal is converted into a luminance signal with high resolution, and is expressed as a good image quality with fine gradation division on the display monitor.

Further, various characteristics of the first data converter 4 can be considered as shown in FIG. 5, for example. Therefore, it is convenient to provide a plurality of first data converters 4 and a selection means therefor so that the one convenient for observation can be selected while looking at the display monitor. In other words, since the ultrasonic diagnostic apparatus is applied to various parts of the human body, it may be inconvenient if the "contrast" of image quality is uniform. Therefore, as shown in FIG. 5, if a plurality of different characteristics are prepared and selectable according to the sense of the observer, effective diagnosis can be performed.

[0014]

According to the present invention, the frame correlation processing circuit, the image memory circuit, the interpolation processing circuit, etc., which are the main parts of the DSC, are not complicated, and therefore the low-to-medium level is achieved without a significant increase in cost. Since the echo signal can be displayed on the display monitor with high resolution, there is an advantage that the image quality of an organ containing a lot of low to medium level echo signals such as the liver can be improved. In addition, the data converter is composed of ROM, and the input / output relation can be selected appropriately,
By preparing a plurality of images with different characteristics, it is possible to obtain monitor images with various types of organs, which have good contrast and suit the observer's senses.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an example of a first data converter shown in FIG.

3 is a characteristic diagram showing another example of the first data converter shown in FIG. 1. FIG.

FIG. 4 is a characteristic diagram showing an example of a second data converter shown in FIG.

FIG. 5 is a characteristic diagram showing different examples of the first data converter.

[Explanation of symbols]

1 ... Ultrasonic probe, 2 ... Front end part (F / E
Part), 3 ... Analog / digital (A / D) converter,
4, 8 ... Data converter, 5 ... Correlation processing circuit, 6 ... Image memory, 7 ... Interpolation processing circuit, 9 ... Digital / analog (D / A) converter, 10 ... Display monitor, 11 ... Digital scan converter ( DSC).

Claims (3)

[Claims] 1. An ultrasonic probe, a front end section including an echo signal detection circuit, an A / D converter for analog / digital converting an echo signal with a resolution of K bits, and N bits per pixel (K> N). ), An ultrasonic diagnosis including an image memory for storing an image, a digital scan converter including a D / A converter for performing a predetermined process on an output from the image memory and then converting the output into an analog amount, and a display monitor. In the apparatus, first data conversion means for converting K-bit data into N-bit data between the A / D converter and the image memory,
An ultrasonic diagnostic apparatus comprising: a second data conversion means for returning N-bit data to K-bit data between the image memory and the D / A converter. Wherein address as said first data conversion means x (bits), the data is constituted by the ROM of y (bits), and the relationship between the address x and the data ^y, x ≒ (r y - 1) / (r-1) where r = 1.03
85. The ultrasonic diagnostic apparatus according to claim 1, wherein an integer that satisfies the following relation is set. 3. The ultrasonic diagnosis according to claim 1, wherein a plurality of the first data conversion means are provided so that the first data conversion means can be selected in accordance with a sense of an observer via the display monitor. apparatus.