JPS583636B2 - 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 tomography apparatus called a CT apparatus (hereinafter abbreviated as CT apparatus).

This CT device is equipped with, for example, an X-ray tube and an X-ray detection device facing each other with a subject in between, and emits, for example, pencil beam-shaped X-rays from the 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 over a normal 18,000 angle range, this data is analyzed by a computer, the X-ray absorption rate of each position on the tomographic plane is calculated, and the tomographic plane is created with a gradation level corresponding to the absorption rate. 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 identify the tomographic structure from soft 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.

In other words, the CT number is the numerical value of the data indicating the individual gradations obtained by analysis in 2000 steps, and the range of all the data obtained by analysis is CT number a~n, and among these, b~ When displaying data in the range up to c (however, a≦b<Cn), as shown in Figure 1, the range of CT numbers b to c should be within the displayable gradation (brightness, color, etc.) range of the CRT. Display the distribution.

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 lower 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, etc. observe the CT images displayed in this way and make a diagnosis, but by taking this one step further, as shown in Figure 2, among the displayed data within the upper and lower limits of the display range, they can select images within a specific range. range b' to C' that is of interest or comparison target (b' is the lower limit of the band value, c' is the upper limit of the band value, b' to C'
The convergence between
If a number is set and displayed in an emphasized manner, it becomes extremely easy to know the presence or absence of a tumor and its distribution, which is effective for diagnosis.

Therefore, conventionally, a CT image display device has been proposed that is capable of further emphasizing and displaying images within a desired specific CT number range from among displayed images within a desired CT number range. .

FIG. 3 is a block diagram showing the configuration of the conventional device,
In the figure, 1 is an input terminal for display data output from a CT device (not shown); 2 is a window level generator that determines the central gradation (CT number) of the CT number range to be displayed;
3 is a window width generator that determines the gradation range (CT number range) of data to be displayed; 4 is a window width generator that calculates the outputs of these window level generators 2 and 3; a window calculator that determines the upper and lower limits of the gradation to be displayed;
5 is a predetermined display level that can be displayed on a cathode ray tube when data falling within the CT number range to be displayed determined by the window width generator 3 is displayed on the cathode ray tube regardless of the gradation level of the data. This is a window correction coefficient generator that generates correction coefficients for converting display data to the corresponding gradation within the gradation range.
M), etc., or store constants in the window width (upper and lower limits of the display range, c and b in Figure 2).
For example, it can be generated by dividing by the width between the two.

6 is set to be the closest gradation when displaying the display data of the CT number larger than the upper limit of the range of gradation to be displayed generated by the window calculator 4 and the output of the band processor 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 the data obtained by subtracting the lower limit value from the data of the OCT number below the upper limit value; 8 is a byte value upper limit generator that generates a desired band value upper limit setting signal; 9 is a desired band value. a band value lower limit generator that generates a lower limit setting signal;
10a is a CT input to the display data input terminal 1;
A comparator 10b compares the display data from the device with the band value upper limit setting signal and extracts data of CT numbers below the band value upper limit; A comparator 11 compares the data 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, and a comparator 11 extracts data that is coincident and outputted from both of these comparators 10a and 10b, that is, data that is within the upper and lower limits of the band value. This is a band processor that takes out input data, and its 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, and this window calculator 4 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.
Each step of gradation from the lower limit to the upper limit of the gradation that can be displayed on a cathode ray tube when displaying a CT reconstructed image on a cathode ray tube, regardless of the size of the CT number of the data that falls within the number range. Complement coefficients for correcting display data are generated and output to the multiplier 7 to allocate them to respective predetermined gradations.

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 highest gradation, and the lower limit value of the CT number range to be displayed is subtracted from the input display data from the CT device, and the result is output to the multiplier 7.

Then, this multiplier 7 multiplies the correction coefficient from the window correction coefficient generator 5 by the data 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 OCT number range among the CT number data in the display range and highlight it, adjust the band value upper limit generator 8 and the band value lower limit generator 9,
Set the upper and lower limits of the desired CT number range.

Among these, the set upper limit 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 OCT numbers below the upper limit value. 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 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 both The band processor 11 detects only those sent simultaneously from the comparators 10a and 10b, thereby detecting C that is within the upper and lower limits of the band value.
Display data of T number is 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 7 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.

However, when performing this highlighted display, in conventional devices, CT numbers that exceed the upper limit of the CT number to be displayed are processed so as to have the maximum gradation interval, and the portion to be highlighted is Since the gradation level during display is also maximized, it is difficult to distinguish between the two on the image, and there is a risk of misdiagnosis.

The present invention has been made in view of the above circumstances, and it sets an arbitrary CT number range among display data of a wide range of gradation levels (a wide range of CT numbers), and converts display data included in this range into a predetermined range. In addition to allocating and displaying data in the range of CT numbers, a desired predetermined range of the display data in the displayed CT number range is displayed at a gradation higher than the predetermined gradation, and display data outside the display range is displayed. An object of the present invention is to provide a display device that can display a clear image that is easy to observe by displaying the image at a specific gradation.

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

FIG. 4 is a block diagram showing a schematic configuration of the device of the present invention, and since the basic configuration is almost the same as the block circuit in FIG. Omitted.

The difference between the device of the present invention and the conventional example is that the window correction coefficient generator 5 receives the output from the window width generator 3 as well as the output from the window width generator 3.
The output from the band processor 11 is also given, and the data falling within the CT number range to be displayed determined by the window width generator 3 is displayed on the cathode ray tube regardless of the gradation level that the data originally has. The output of the band processor 11, that is, the OCT number of the range to be further emphasized and displayed in the display data, is generated. The configuration is such that a correction coefficient is generated for the data so that the display gradation is near the maximum.

That is, in the apparatus configured as described above, data of CT numbers in a range of 2000 steps is input as a digital signal from a CT device (not shown) to the input terminal 1.

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, that is, the center CT number, and the window width generator 3 determines the size of the gradation range to be displayed, that is, the center CT number. , a range of CT numbers 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. The upper limit value (FIG. 5C) and lower limit value (FIG. 5b) are calculated.

On the other hand, the output of the window width generator 3 is also given to a window correction coefficient generator 5.
Data falling within the number range is allocated to each stage of the gradation level from the lower limit to near the upper limit that can be displayed by the cathode ray tube 15 when displaying the data as a CT reconstructed image regardless of the size of the data OCT number. Correction coefficients for correcting display data are generated to provide respective predetermined gradations, and are output to the multiplier 7.

The display data input to the input terminal 1 is input to the display data calculator 6, and this display data calculator 6 calculates the upper limit value of the CT number to be displayed (FIG. 5C) calculated by the window calculator 4. ) or above is processed so that the input data with a CT number that is larger than b) in FIG. 5 is subtracted and outputted to the multiplier 7.

Then, this multiplier 7 multiplies the correction coefficient from the window correction coefficient generator 5 by the data 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 within 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 define and highlight a more specific CT number range (for example, between c' and b' in FIG. 5) among the CT number data in the display range, the band value upper limit generator 8
and band value lower limit generator 9 are adjusted to set the upper limit C' and lower limit b' of the desired CT number range.

Among these, the set upper limit 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 the comparators 10a use this display data and the upper limit value C.
The comparator 10b compares the input display data with the lower limit value b' and outputs display data for CT numbers that are equal to or higher than the lower limit value. and sends each to the band processor 11.

Since the display data input to the comparators 10a and 10b are the same at the same time, the outputs of the comparators 10a and 10b sent to the band processor 11 are of the same bale display data. By detecting only the data sent simultaneously from the comparators 10a and 10b by the band processor 11, display data of CT numbers included in the range between the upper limit value C' and lower limit value b' of the band value can be obtained. can get.

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

Further, the output of the band processor 11 is also given to the window correction coefficient generator 5.
When performing band processing, outputs a correction coefficient slightly smaller than the above correction coefficient and supplies it to the multiplier 7.

In other words, the correction coefficient is obtained by dividing a constant by the window width, but if the highlighting range is set, the constant is made smaller than in the normal case and the correction coefficient is adjusted. As shown in Figure 1, the range of data to be displayed that is above the upper limit C is set to the maximum gradation, and if a highlighted display range is set, the data that is above the upper limit C is set to a slightly lower gradation than the maximum as shown in Figure 5. , the highlighted display range is corrected to have the maximum gradation.

The data processed and outputted by the display data calculator 6 as described above is supplied to the multiplier 7, which multiplies the output of the display data calculator 6 by the correction coefficient as described above and applies correction.

Thus, the output of the display data calculator 6 is corrected in display gradation as shown in FIG. 1 under normal conditions, and as shown in FIG. 5 when a highlighted display range is set.

Specific lower bits of the data corrected by the multiplier 7 are sent to the D/A converter 12 where it is converted into an analog signal and sent to the mixer amplifier 14.

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.

Video signals that are above the upper limit of the CT number in the display range are normally at the maximum gradation level, and those with CT numbers within the display range that are lower than that are at each gradation level that can be expressed by the cathode ray tube 15. Corrected so that they are displayed in correspondence with each other as shown in Figure 1, and when a highlighted display range is set, the highlighted range is the maximum gradation level and the data of the CT number in the display range is corrected. The data above the upper limit is suppressed to a predetermined gradation slightly lower than the maximum, and the CT number data within the display range is corrected so that it is displayed as shown in Figure 5 by allocating it to a gradation below the predetermined gradation. Therefore, data in a desired range can be displayed and data in a specific range within the desired range can be highlighted.

Moreover, the highlighted display range is displayed at the maximum gradation level, and the highlighted display area can be clearly distinguished from other parts, allowing for accurate diagnosis.

Among the CT display data covering a wide range of gradations, an arbitrary CT number range is set, and the display data included in this range is allocated to the range of gradations that can be expressed by the cathode ray tube, and the corresponding gradations are calculated. In addition, the display data with CT numbers above the upper limit of the set display range is processed and displayed at the maximum gradation, and the display data with CT numbers in a specific range is further emphasized in the display data. When displaying, the correction is made smaller and the gradation range for cathode ray tube display is narrowed to leave an area near the maximum gradation so that the data to be highlighted is at the maximum gradation, so any display data It is possible to provide a display device for a CT apparatus that has excellent features such as being able to display data in an easy-to-read manner, and highlighting data being clearly distinguishable from other data, making diagnosis easier.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be practiced with appropriate modifications within the scope of the invention without changing its gist.

[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. A diagram illustrating an example in which a specific range within the display range is defined and highlighted, FIG. 3 is a block diagram showing the configuration of a conventional device, and FIG. 4 is a block diagram showing an embodiment of the present invention. Figure, 5th
The figure is a diagram showing how gradation is added for highlighting according to the present invention. 2... Window bell 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, 1
1... 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 center gradation 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 calculation unit that performs the display, a circuit that sets a range of arbitrary gradations within the range of 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. - At the same time, display data calculation that processes display data with gradations located above the upper limit value to a lower gradation than the maximum, and display data within the setting range of the band processor to the maximum gradation. and a correction coefficient for correcting the display data that falls within the range to be displayed set by the window width generator to the optimum gradation when displaying, and also generates a correction coefficient that is set by the band processor. a correction coefficient generator that generates a correction coefficient that is an appropriate reduction of the correction coefficient when the correction coefficient is corrected; a multiplier that performs correction by multiplying the correction coefficient by the output of the display data calculator; A display device comprising a device for displaying data as an image.