JPH0614924B2 - Image display device in CT device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention is used in the field of Computed Tomography (CT).

The present invention relates to an image display mechanism for arithmetic processing and data transfer between a reconstructed image memory and a display image memory in a CT device.

(B) Prior art For image reconstruction of a CT device, filter-corrected backprojection (filt
ered back projection) method is widely used,
Since the amount of calculation is very large, a dedicated image reconstruction calculation device is manufactured. In the case of an X-ray CT apparatus, the reconstructed image data is transferred to a display device and displayed by a display. On the other hand, in general, the reconstructed image data is not represented by the CT value, and therefore, is converted into the CT value while being transferred to the display device. For example, a portion having an X-ray absorption value equivalent to water is displayed with a CT value of 0, and a portion equivalent to air is displayed with a CT value of -1000. Further, the reconstructed matrix and the display matrix do not generally coincide with each other, and the reconstructed image is usually displayed by two-dimensional interpolation. These CT value conversion, interpolation calculation, and data transfer are performed through a host computer that manages an image reconstructing device, a display device, etc. However, as the reconstruction matrix increases, the processing time also increases accordingly.

That is, the time for displaying the reconstructed image is defined by the calculation capacity and data transfer rate of the host computer that executes CT value conversion / interpolation calculation and data transfer. It has been proposed that the time required for image display caused by this calculation and data transfer be shortened.

(C) Objective An object of the present invention is to provide a CT apparatus having an image display mechanism that can shorten the time from image reconstruction to image display.

(D) Structure The above-mentioned object is to provide a CT value converter for converting image data of the reconstructed image memory into a CT value between the reconstructed image memory and the display image memory, and data converted into the CT value. And an image interpolator for interpolating the interpolation data and storing the interpolated data in the display image memory, between the CT value converter and the image interpolator, and between the reconstructed image memory and the CT value converter. This is achieved by connecting a dedicated bus between the display image memories.

(E) Embodiments Preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flow chart showing processing from image reconstruction to image display by collecting projection data from a detector. Since the reconstructed data is not generally represented by a CT value, it needs to be converted into a CT value first. The data converted into the CT value may be displayed as it is, but is often double-interpolated and displayed. For example,
If the reconstruction matrix has 320 × 320 pixels, the display matrix has 640 × 640 pixels. Therefore, the display is performed after the image interpolation processing.

Conventionally, reconstructed image data is sent to a host computer, where CT value conversion / image interpolation processing operations are performed and then sent to a display device.

FIG. 2 is a block diagram of essential parts showing one embodiment of the present invention. 1 is an image reconstruction device, 2 is an image display device, 3 is a reconstructed image memory, 4 is a CT value converter, 5 is an image interpolator,
6 is a display image memory, 7 is a display, 8 is a host computer, 9 is a data bus of the host computer 8,
10 is a dedicated bus between the CT value converter 4 and the image interpolator 5, and 14 is a display image storage device.

The image reconstructing apparatus 1 has a CT value converter 4 therein, and the image data in the image memory 3 is directly sent to the CT value converter 4 and converted there. The data converted into the CT value can be taken into the computer 8 via the bus line 9 of the host computer 8.
Alternatively, it can be sent directly to the image display device 2 via the dedicated bus 10. On the other hand, in the image display device 2, the image interpolator 5 performs two-dimensional interpolation of the reconstructed image and stores the image in the display image memory 6.

When the region of interest in the image in the display image memory 6 is enlarged and displayed, the image data of the region is sent to the host computer 8 and the data is returned to the display image memory 6 via the image interpolator 5. Can be achieved by The same enlargement processing can be executed without passing through the host computer 8 by setting a bidirectional bus between the display image memory 6 and the image interpolator 5 and reciprocating the data.

Conventionally, the time for displaying the reconstructed image data by performing the above-mentioned processing by the host computer 8 increases as the reconstruction matrix increases, and the time reaches several seconds to about 10 seconds. In the illustrated embodiment, the display time can be suppressed within 0.5 to 1 second even if the reconstruction matrix is sufficiently large, and the image display time can reach a value within a common sense range.

The X-ray CT apparatus is usually equipped with an image storage device 14 having a function of storing images. This storage device 14 is useful because an increase in the reconstruction matrix leads to an increase in the display matrix, and a large amount of data transfer is required to store one image. In the past, this data transfer was also performed via the host computer, but in this embodiment, high-speed data transfer is performed without the host computer 8 by disposing the dedicated bus 15.
As another application, the private bus 15 is covalently coupled to the private bus 10.

Further, even if the calculation processing of CT value conversion and image interpolation in the host computer 8 is omitted and the dedicated bus 10 is not set, the display time can be shortened to some extent. The data flow in this case is image memory 3 → CT value converter 4 → host computer → image interpolator 5 → display image memory 6.

FIG. 3 is a block diagram of essential parts showing another embodiment.
An arithmetic unit 11 for displaying an image is located between the image reconstructing device 1 and the image displaying device 2, and they are connected by dedicated bars 12 and 13. This embodiment is useful for remodeling and assembling by inserting the arithmetic unit 11 using a conventional device and connecting two dedicated buses.

(F) Effects The present invention has the effects that the speed of displaying a reconstructed image can be increased and that calculation hardware such as a CT value converter and an image interpolator can be effectively used.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of processing from image reconstruction to image display in a CT apparatus, FIG. 2 is a block diagram of essential parts showing one embodiment of the present invention, and FIG. 3 is another embodiment. 2 is a block diagram similar to FIG. 1 is an image reconstructing device, 2 is an image display device, 3 is a reconstructed image memory, 4 is a CT value converter, 5 is an image interpolator, 6 is a display image memory, 8 is a host computer, 11 is a display computing unit. , 10 and 12 and 13 are private buses.

Claims (1)

[Claims] 1. A CT value converter for converting the image data of the reconstructed image memory into a CT value between the reconstructed image memory and the display image memory, and interpolation data for interpolating the data converted into the CT value. And an image interpolator for storing in the display image memory, between the CT value converter and the image interpolator, between the reconstructed image memory and the CT value converter, and further between the image interpolator and the display image memory. An image display device in a CT device, characterized in that a dedicated bus is connected to each.