JPS583635B2 - display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used in a computer tomography device,
The present invention relates to a display device that displays the reconstructed image.

Computerized tomography is one of the radiation tomography devices.
There is an X-ray analysis layer imaging device called y (hereinafter abbreviated as CT device).

For example, an OCT device is equipped with an X-ray tube and an X-ray detection device facing each other with a subject in between, and emits, for example, a pencil beam of X-rays from the X-ray tube, and a tomographic plane of the subject. They are moved in the same direction and at the same speed, and each time they are moved, the angle with respect to the tomographic plane is changed by 1 degree and the process is repeated. From then on, while sequentially changing the angle, various angles of the tomographic plane of the subject are moved. Collect X-ray absorption data for

After collecting data in an angular range of 180°, this data is analyzed by a computer, the X-ray absorption rate at each position on the tomographic plane is calculated, and the gradation level corresponding to the absorption rate is calculated. The composition of each part of the tomographic plane can be analyzed in as many as 2,000 gradations depending on the X-ray absorption rate, so it is possible to clearly reproduce the tomographic structure from soft tissue to hard tissue. An image is obtained.

By the way, this CT display data, which is expressed in 2000 levels of gradation according to the X-ray absorption rate, is -100 on the black level side.
The white level side is analyzed into a total of 2000 levels between 0 and +1000, but when displaying an image on a cathode ray tube, the data of interest is usually selected from among the 2000 levels of data due to its expressive ability. A certain arbitrary specific range is set and displayed.

That is, assuming that the numerical value of the data indicating each gradation level obtained by analyzing in 2000 steps is the CT number, and the range of all the data obtained by analysis is CT number a to n, among these, b to c (However, when displaying data in the range s≦b≦c≦n, the range of CT numbers b to C is divided into the displayable gradation (brightness, color, etc.) range of the CRT as shown in Figure 1. Display.

Then, data with CT numbers outside of this display range, that is, in the example of Figure 1, data with CT numbers below B (below the upper limit of the display range) and above C (above the upper limit of the display range) are displayed in a specific gradation. so that it can be clearly distinguished from the data in the range b to c.

Doctors and others observe the CT images displayed in this way and make a diagnosis, but by taking this one step further, as shown in Figure 2, a more specific The upper limit of the band value is the comparison target or interest within the range, and the width between b' and C' is called the band width)
By emphasizing and displaying a tumor in a specific gradation, for example, by setting a CT number indicating a tumor and displaying it in an emphasized manner, it becomes extremely easy to know the presence or absence of a tumor and its distribution. Diagnostically effective.

The present invention has been made in view of the above circumstances, and it
It is an object of the present invention to provide a display device for CT images that can further emphasize and display images within a desired specific OCT number range from among displayed images within a range of numbers.

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

FIG. 3 is a block diagram showing a schematic configuration of this device, in which 1 is an input terminal for display data output from a CT device (not shown), and 2 is a gradation level that is the center of the CT number range to be displayed. 3 is a window width generator that determines the size of the gradation range (CT number range) to be displayed; 4 is the window level generator 2 and window width generator a window calculator which calculates the output of 3 and determines the upper and lower limits of the gradation to be displayed based on the window level output and window width output; 5 falls within the range to be displayed determined by the window width generator 3; This is a window correction coefficient generator that generates correction coefficients for converting display data so that it has a constant gradation when displaying data regardless of the size of the range to be displayed. can be generated by storing it in advance in a memory such as a read-only memory (ROM), or by dividing a constant by the width of the window (the upper and lower limits of the display range, the width between c and b in Figure 2). etc.

6 is the maximum gradation when displaying the display data of the CT number larger than the upper limit of the range of gradations to be displayed generated by the window calculator 4 and the output of the band processor 11 to be described later. A display data calculator 7 processes the display data and subtracts the lower limit value of the gradation range to be displayed from the display data. A multiplier that multiplies data obtained by subtracting a lower limit value from the data of CT numbers below the upper limit value, 8 a band value upper limit generator that generates a desired band value upper limit setting signal, 9 a desired band value A band value lower limit generator 10a generates a value lower limit setting signal, which compares the display data from the CT device inputted to the display data input terminal 1 with the band value upper limit setting signal and determines a CT number that is less than or equal to the band value upper limit. 10b is a comparator that compares the display data from the CT device inputted to the display data input terminal 1 with the band value lower limit setting signal and extracts data of CT numbers that are equal to or higher than the band value lower limit. , 11 are these comparators 10a, 10
A band processor that extracts data output from both sides, that is, data that falls within the upper and lower limits of the band value,
The output is outputted via the display data calculator 6 together with the output of the display data calculator 6.

12 is D for converting the output of the multiplier 7 into an analog signal.
13 is a synchronizing signal generator that generates a synchronizing signal; 14 is a synchronizing signal generator that synchronizes with the D/A converter;
A mixer amplifier 15 converts the output of the A converter 12 into a video signal, and 15 is a cathode ray tube that is synchronized with the synchronization signal output from the synchronization signal generator 13 and displays the output of the mixer amplifier 14 as an image.

Next, the operation of this apparatus having the above configuration will be explained.

Data of OCT numbers in a range of 2000 steps is input as a digital signal to an input terminal 1 from a CT device (not shown).

Among these data, the window level generator 2 and window width generator 3 are adjusted to determine the range of CT numbers to be displayed.

Then, the window level generator 2 determines the center gradation of the range to be displayed, ie, the CT number, and the window width generator 3 determines the size of the gradation range to be displayed, ie, the CT number. The range of is determined.

The outputs of the window level generator 2 and window width generator 3 are given to the window calculator 4, which calculates the gradation to be displayed, that is, the CT number to be displayed, based on the set level and width. Calculate the upper limit value and lower limit value.

On the other hand, the output of the window width generator 3 is also given to a window correction coefficient generator 5, and this window correction coefficient generator 5 calculates the CT to be displayed based on the given signal.
Data that falls within the number range is applied to each step of the gradation level from the lower limit to the upper limit of the gradation level that can be displayed by the CRT when displaying a CT reconstructed image on a CRT, regardless of the size of the data OCT number. A correction coefficient for correcting the display data is generated and output to the multiplier 7 to allocate each to a predetermined display gradation.

The display data input to the input terminal 1 is input to the display data calculator 6, and the display data calculator 6 calculates the CT number calculated by the window calculator 4, which is larger than the upper limit of the CT number to be displayed. The input data is processed to have the maximum gradation, and the lower limit value of the CT number range to be displayed is subtracted from the input display data from the CT apparatus, and the result is output to the multiplier 7.

Then, the multiplier 7 multiplies the correction coefficient of the window correction coefficient generator 5 by the data that has been subjected to the lower limit subtraction processing described above among the processed data from the display data calculator 6 and outputs the result.

As a result of this multiplication, if a specific lower bit is taken, the data of the CT number in the display range will have a predetermined gradation among the gradations corresponding to the width of the display range.

On the other hand, in order to further define a specific CT number range among the CT number data in the display range and display it in gradation, the band value upper limit generator 8 and the band value lower limit generator 9 are adjusted.
Set the upper and lower limits of the desired CT number range.

Among these, the set old value is inputted to the comparator 10a, and the set lower limit value is inputted to the comparator 10b as a reference signal.

Display data from the CT device is input to these comparators 10a and 10b, and the comparator 10a compares this display data with an upper limit value and outputs display data of CT numbers below the upper limit value. The device 10b compares the input display data with a lower limit value, outputs display data with CT numbers greater than or equal to the lower limit value, and sends them to the band processor 11, respectively.

Since the display data input to the comparators 10a and 10b are the same and are input at the same time, the outputs of the comparators 10a and 10b sent to the band processor 11 are of the same display data, and therefore, By detecting only what is simultaneously sent from both comparators 10a and 10b by the band processor 11, display data of CT numbers included within the upper and lower limits of the band value can be obtained.

This data is processed by the display data calculator 6 so as to obtain the maximum gradation.

The data processed in the display data calculator 6 and corrected in the multiplier 1 in this way has specific lower bits sent to the D/A converter 12 where it is converted into an analog signal and then sent to the mixer amplifier. Sent to 14th.

A synchronizing signal is applied to this mixer amplifier 14 from a synchronizing signal generator 13, and while synchronizing with this synchronizing signal, this mixer amplifier 14 converts the data converted into analog by the D/A converter 12 into a video signal. and feed it to the cathode ray tube 15.

Then, the cathode ray tube 15 displays the video signal as an image while being synchronized with the synchronization signal output from the synchronization signal generator 13.

The video signal is displayed at the maximum gradation level for CT numbers above the upper limit of the display range and those within the band value that should be displayed with emphasis among the CT numbers within the display range, and for CT numbers other than those listed above.
Each number has been corrected to have a specific gradation, so as shown in Figure 2, it is possible to display an image using data within an arbitrary CT number range and data within a further specific range within that range. is highlighted.

In this way, data in a desired display range (desired CT number range) is displayed as an image with gradation from among the display data including a wide range of CT numbers sent from the CT device, and the display range is CT number data in a specific range within the range and data above the upper limit of the display range can be displayed at the maximum gradation, so while observing an image in the set display range, you can display CT number data in a specific range within that range. By highlighting and displaying the range OCT number data, the effectiveness of diagnosis can be dramatically improved. For example, if you highlight the CT number data that indicates a tumor, you can easily discover it. A display device having the following can be provided.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings; it goes without saying that the present invention can be practiced with appropriate modifications within the scope without changing the gist thereof.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining an example of the setting range of CT numbers to be displayed among display data obtained by a CT device and the state of addition of gradation for display. FIG. 3 is a block diagram illustrating an embodiment of the present invention. 2...Window level generator, 3...
・Window width generator, 4... Window calculator, 5... Window correction coefficient generator, 6...
... Display data calculator, 7... Multiplier, 8
...Band value upper limit generator, 9...Band value lower limit generator, 10a, 10b...Comparator,
11... Band processor, 15... Braun tube.

Claims (1)

[Claims] 1. In a computer tomography device that displays display data analyzed into multiple gradations as an image, a window level generator that sets the gradation that is the center of the range of gradations to be displayed among the display data. and a window width generator for setting the range of gradations to be displayed in the display data, and calculating the upper and lower limits of the range of gradations to be displayed from the setting outputs of these window level generators and window width generators. A window computing unit that performs the display, a circuit that sets an arbitrary gradation range within the range between the upper and lower limits of the gradation to be displayed, and a set value that compares the set value of this circuit with the display data. a band processor that obtains display data within the range of , and subtracts the lower limit value calculated by the window calculator from the display data of the gradation located below the upper limit value calculated by the window calculator. and a display data calculator that processes display data of a gradation located above the upper limit value and display data corresponding to the display data output from the band processor so as to have the highest gradation, and the window width generator. a window correction coefficient generator that generates a correction coefficient for correcting the display data corresponding to the range to the optimum gradation when displayed in accordance with the range set by the device; A display device comprising a multiplier that performs correction by multiplying the output of a display data calculator, and a device that displays data corrected by the multiplier as an image.