JPH06205780A - Ultrasonic image processor - Google Patents

Abstract

PURPOSE:To provide an ultrasonic image processor capable of retrieving the degree of the contrast of the remarked region and invariably making the con trast reinforcement suitable to the region. CONSTITUTION:When two regions having a small density difference are to be clarified, the desired region is encircled with a frame, then a frame readout circuit 4 outputs the region extraction signal 101 to a frame memory 2. The frame memory 2 outputs the present image data of the prescribed region encircled by the frame to a histogram circuit 7 according to the region extracting signal 101. The histogram circuit 7 generates a histogram based on the present image data of the prescribed region encircled by the frame. This histogram is smoothed by a histogram smoothing circuit 11, and the peak value of the smoothed histogram is retrieved by a peak value retrieving circuit 15. A picture element value emphasizing circuit 3 determines a new density value based on the retrieved peak value and displays an image in the prescribed region centering on the remarked picture element encircled by the frame based on the new density value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic image processing apparatus used in an ultrasonic diagnostic apparatus, and more particularly, an ultrasonic image capable of selecting a range of a frame surrounding a predetermined area centered on a pixel of interest in pixel information. Regarding a processing device.

[0002]

2. Description of the Related Art Conventionally, in an ultrasonic diagnostic apparatus, when two regions having a large gray scale difference in an obtained ultrasonic image, for example, a bone and an internal organ have different ultrasonic reflectances,
Bone is displayed in white and visceral organs are displayed in gray and are clearly displayed due to the large difference in contrast. There is a function to change the assignment of the gray scale bar as a process process.

[0003]

However, the functions of adjusting the contrast and changing the assignment of the gray scale bar are performed for the entire screen, and there is a problem that the image quality is hard. Also,
The functions of adjusting contrast and changing the assignment of the gray scale bar remain as they are once set, and in order to clarify the two regions with different gray levels that have different levels in the ultrasonic image that changes from moment to moment. Had to be reset according to the level, and the trouble was complicated.

The present invention has been made to solve the above problems, and provides an ultrasonic image processing apparatus capable of constantly searching the degree of contrast of a region of interest and constantly enhancing the contrast suitable for the region. It is intended to be provided.

[0005]

The present invention has been made in view of the above-mentioned circumstances, and an ultrasonic image processing apparatus according to the present invention provides a pixel group in a predetermined area centered on a pixel of interest in pixel information. A histogram creating means for creating a histogram, a peak value searching means for searching for a peak value of the histogram created by the histogram creating means, and a pixel value emphasizing means for carrying out a contrast emphasizing process only on a target pixel by a gray value table stored in advance. And a predetermined area is surrounded by a frame by the frame selecting means, and contrast enhancement is performed only on the predetermined area surrounded by the frame.

[0006]

In the ultrasonic image processing apparatus according to the present invention having the above-described structure, the frame selecting means encloses a predetermined area in a frame, and the histogram creating means makes a histogram of a pixel group within a predetermined area centered on a pixel of interest in the pixel information. The peak value of the histogram created by the histogram creating means is searched by the peak value searching means, and only the predetermined area centered on the pixel of interest surrounded by the frame by the gray value table stored in advance by the pixel value emphasizing means is created. By performing contrast enhancement processing, optimal contrast enhancement can be performed in a predetermined area centered on the pixel of interest surrounded by a frame in real time.

[0007]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an ultrasonic image processing apparatus according to the present invention.

The ultrasonic image processing apparatus includes an A / D converter 1 for A / D converting an ultrasonic reception signal (analog signal).
The A / D converter 1 has an A / D-converted ultrasonic wave reception signal (digital signal) 100 for one screen.
Is connected to a pixel memory 2 for storing a pixel value enhancement circuit 3 described later. Furthermore, the ultrasonic image processing device
It has a frame memory read circuit 4 for inputting to the frame memory 2 an area extraction signal 101 for extracting a predetermined area centered on a pixel of interest surrounded by a frame by an input signal from an operation unit (not shown). The frame memory 2 receives the data Xi of a predetermined area centered on the pixel of interest in accordance with the area extraction signal (address) from the frame memory read circuit 4.
Is output.

A pixel value emphasizing circuit 3 and a selector 5 described later are connected to the frame memory 2, and the selector 5 selects a signal from the frame memory 2 or a signal from the histogram read counter 6. It has become. Further, the selector 5 is connected to a histogram forming circuit 7 that creates a histogram of a predetermined area centered on the pixel of interest surrounded by a frame.
Is a histogram RAM 8 and an increment circuit 9
And a latch 10.

Further, the histogram forming circuit 7 includes a histogram smoothing circuit 1 for smoothing the created histogram.
1 is connected, and the histogram smoothing circuit 11
The shift register 12 includes an adder 13 that adds eight data before and after, and a latch 14.
The histogram smoothing circuit 11 and the histogram read counter 6 are connected to a peak value searching circuit 15 for searching the peak value P of the histogram smoothed by the histogram smoothing circuit 11, and the peak value searching circuit 15 It is composed of a comparator 16 which compares a previous peak value with a current peak value and outputs a latch signal only when the current peak value is large, and latches 17 and 18.

Further, the peak value search circuit 15, the frame memory 2 and the A / D converter 1 are connected to a pixel value emphasizing circuit 3 for emphasizing the contrast of a predetermined area centered on the pixel of interest surrounded by a frame. , The pixel value emphasis circuit 3
The subtracter 19 for subtracting the peak value P of the previous image data retrieved by the peak value retrieval circuit 15 from the current image data Xi in the predetermined area centered on the pixel of interest surrounded by the frame, and the output from the subtractor 19 (Xi -P) in contrast enhancement constant K
20 and the output K (Xi-
P) is added with a peak value P, and a selector 22 for selecting a signal from the A / D converter 1 or a signal output from the adder 21.

As shown in FIG. 2, the histogram has a Gaussian distribution. This Gaussian distribution expands when the contrast is increased, and narrows when the contrast is decreased. As shown in FIG. 3, the current histogram shape shown in FIG. 3 is changed so as to spread around the peak value, whereby the contrast can be increased. That is, the contrast can be increased by creating a gray value table that spreads the shape of the histogram around the peak value and redisplaying the image. When a histogram as shown in FIG. 2 is obtained, a new gray value Yi is calculated by the following equation, where P is a gray value having a peak value and Xi is a current gray value of each pixel.

Yi = K (Xi-P) + P Next, the operation of this embodiment will be described.

An ultrasonic wave reception signal (analog signal) obtained by the ultrasonic diagnostic apparatus is converted into a digital signal 100 by the A / D converter 1 and displayed on a display device (not shown) via the selector 22. At this time, the ultrasonic wave reception signal 100 converted into a digital signal by the A / D converter 1 is stored in the frame memory 2.

Then, when it is desired to make clear two regions having a small gray scale difference in the image displayed on the display device, the operator encloses the desired region with a frame by an operation unit (not shown). Then, the input signal from the operation unit is input to the frame memory reading circuit 4, and is output from the frame memory reading circuit 4 to the frame memory 2 as the area extraction signal 101. Then, the frame memory 2 subtracts the current image data Xi of the predetermined area centered on the pixel of interest surrounded by the frame from the data of one screen according to the address specified by the area extraction signal 101 by the subtracter 19 of the pixel value emphasizing circuit 3. To the histogram forming circuit 7 via the selector 5.

Further, the histogram forming circuit 7 is arranged so that the current image data Xi in a predetermined area centered on the pixel of interest surrounded by the frame is present.
Based on the above, a histogram as shown in FIG. 2 is created. Then, the histogram created by the histogram forming circuit 7 is smoothed by the histogram smoothing circuit 11. For example, smoothing is performed by adding eight pieces of data before and after the addition by the adder 13.

The peak value P of the histogram smoothed by the histogram forming circuit 7 is searched by the peak value searching circuit 15. That is, the comparator 16
By comparing the previous peak value with the current peak value, the latch signal is latched 1 only when the current peak value is large.
Output to 7 and 18. Further, the peak value P output from the latch 18 is input to the subtractor 19, and the subtractor 19 subtracts the peak value P from the current image data Xi in a predetermined area centered on the pixel of interest surrounded by the frame and subtracts it. Value Xi-
Output P to the multiplier 20.

Then, the multiplier 20 multiplies the output Xi-P of the subtractor 19 by the contrast enhancement constant K and adds it to the adder 21.
To the output K of the multiplier 20 (Xi-
The output P of the peak value search circuit 15 is added to P) to obtain a new gray value Yi. Then, an image of a predetermined area centered on the pixel of interest surrounded by the frame by the new gray value Yi is displayed.

For example, when K = 2 and P = 100,
As shown in FIG. 4, Yi becomes smaller than the value of Xi as Xi becomes smaller than 100, and Yi becomes larger than the value of Xi as Xi becomes larger than 100.
The contrast is increased.

[0021]

As described above, according to the present invention,
The histogram creating means creates a histogram of a pixel group within a predetermined area centered on a pixel of interest surrounded by a frame in the pixel information, and the peak value searching means searches the peak value of the histogram created by the histogram creating means to obtain the pixel value. Since the contrast enhancement processing is configured to perform only the predetermined area centered on the pixel of interest surrounded by the frame by the gray value table stored in advance by the emphasizing means, the predetermined area centered on the target pixel surrounded by the frame in real time is displayed. Optimal contrast enhancement can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an ultrasonic image processing apparatus according to the present invention.

FIG. 2 is a diagram showing a histogram created by a histogram forming circuit according to the present invention.

FIG. 3 is a diagram showing a histogram on which contrast enhancement processing is performed by a pixel value enhancement circuit according to the present invention.

FIG. 4 is a diagram for explaining the operation of the present invention.

[Explanation of symbols]

 3 Pixel value emphasis circuit 7 Histogram formation circuit 11 Histogram smoothing circuit 15 Peak value search circuit

Claims (1)

[Claims] 1. An ultrasonic image processing apparatus capable of selecting a range of a frame surrounding a predetermined area centered on a pixel of interest in pixel information, a histogram creating means for creating a histogram of a pixel group in the predetermined area, and a histogram creation A peak value search means for searching the peak value of the histogram created by the means, and a pixel value emphasizing means for performing a contrast emphasizing process only on a predetermined area centered on the pixel of interest using a gray value table stored in advance. An ultrasonic image processing apparatus, characterized in that a predetermined area is surrounded by a frame by a selection means, and contrast enhancement is performed only on a predetermined area centered on a pixel of interest surrounded by the frame.