NL8401215A - BUFFER MEMORY DEVICE. - Google Patents

Description

* Η.ο. 52415 1 s ·· - ... .........

Short designation: Buffer memory device.

The invention relates to diagnostic imaging equipment and more particularly relates to a buffer memory device for use in such equipment.

Diagnostic imaging equipment generally has discs for storing multiple image data. While the data is being acquired, it is temporarily stored in buffer memories. Also, while the 10 data are being obtained, the doctor or clinical assistant can look at the display of the images being obtained.

The buffer memory is used because it speeds up the acquisition registration process. The commonly used end-disk memory only receives data at a relatively low speed, although it is capable of holding a large amount of data. The speed of data feeding to most disk memory devices precludes obtaining a large number of images that are often required for the physician for diagnostic purposes in a time frame that will be comfortable for the patient.

In addition to patient comfort, the use of such acquisition equipment inherently exposes the patient to radiation. It is always a good practice to minimize the patient's exposure to radiation for safety reasons. Most firms in the field of manufacturing such equipment strictly follow a policy of minimizing exposure of the patient to radiation. Hence, the diagnostic imaging equipment manufacturing industry aims to minimize exposure of patients to radiation.

For the above reasons, buffer memories are used. The buffer memories can record and store the data at a rate approximately twice that of a disc. These buffer memories are generally of limited size and therefore the amount of data that can be stored in a buffer is much smaller than the amount that can be stored in a disk.

There are times when more data is needed than can be stored in the buffer memory. Then the person conducting the study must discontinue obtaining the 40 buffer at the relatively slow rate required by the disc 8401215 ____________________________________________________________ 2 ...........________........ .. _......................

is unloaded. Discontinuation of procurement has many inherent drawbacks, the most obvious of which are that the patients' organs do not stop, that any contrast material drains, and that the patient's position may be changed when resumption is obtained.

There are solutions to the problems encountered in using buffer memories with diagnostic imaging equipment available today. For example, very large buffer memories can be used. This solution increases the mass and cost of the device. A currently available solution that also increases the cost of the device is to use a very fast write disk memory.

Another solution is to slow down the speed of image acquisition and image transfer between acquisition. There are objections to the slower speeds as they cannot allow proper temporary resolution of the object.

Accordingly, there is a need for buffer memory devices for use in diagnostic imaging where the buffer memory and disk are both relatively inexpensive and unnecessarily bulky.

According to an embodiment of the invention, a buffer memory device for use in diagnostic image systems is provided, which device comprises: - an image acquisition system, - a buffer memory device for temporarily storing images obtained by the system, - means for loading the buffer memory at a speed R1, which rate R1 comprises at least 12.5 frames per second, - a long-term memory device for holding the images, and - means for unloading the buffer memory device while the image is loaded therein with an unloading rate of R2.

A feature of the invention is a buffer memory device in which the loading speed R1 is at least 25 frames per second and the unloading speed R2 is at least 12.5 frames per second.

The invention will be further elucidated on the basis of a preferred embodiment with reference to the accompanying drawing, in which a buffer memory device for use in digital fluoroscopy systems is shown in block diagram.

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The diagnostic imaging system XI shown in the figure has a buffer memory device 13. The system 11 is a well-known digital fluoroscopy imaging system. The image is obtained by the block 14. The output signals from the block 14 are the 5 digital signals used to provide the display on the monitor 16. It is these signals that are also stored in the long-term storage device, such as the disk 17. Since the loading speed of feeding data to the disk is relatively slow, the buffer memory device 13 is used.

As mentioned above, it is advantageous to make the buffer memory device as small and cheap as possible without adversely affecting the image quality of dose usage.

The buffer memory device 13 in the preferred embodiment is a semiconductor storage matrix. The advantage of such buffers is that they can be loaded quickly and store significant amounts of data. Loading is accomplished in the indicated system under the control of the logic system unit 18, resp. controls the x and y reader units 19 and 21.

The unloading is realized when the x and y 20 readout units 22 and 23, respectively. be ratified. The readout speed is determined by the speed at which the final memory 17 can record the data.

The reading or loading speed in the preferred embodiment is approximately 6.25 megabytes per second when the buffer 25 is a 512 x 512 matrix, and is approximately 1.5625 megabytes per second when the unit 13 is a 256 x 256 matrix. In contrast, the unloading speed is approximately 0.8 megabytes per second.

In the preferred embodiment, the capacity of the memory is approximately 62 images. Since the transfer rate in the buffer is about 25 images per second, the result is that the buffer is filled in less than two seconds under normal conditions. In prior art operation, obtaining usually had to be stopped while the buffer was being unloaded to the disk.

In the system now described, the logic unit controls loading and unloading to effect these operations substantially simultaneously. This procedure significantly increases the time required to fill the buffer. The system 40 therefore functions as if it has a larger buffer than there is in fact 8401215 \ 4 present. The following table illustrates the increase in load that the buffer can handle when obtaining at a rate of 25 frames per second when using a 256 x 256 matrix for the buffer and when unloading at a rate of 12.5 frames per second. second occurs.

: Expired: Frames: Frames: Frames that remain in:: Time (sec): Loaded: Unloaded: Buffer:: 1: 25: 12.5: 12.5:: 2: 50 s 25: 25.0:: 3: 75: 37.5: 37.5:: 4: 100: 50: 50.0; 15: 5: 125 i 62.5: 62.5:

The effective capacity of the buffer is therefore doubled by using the described system. The advantage is particularly important when the rate of acquisition is high. Thus, when the rate of acquisition of the system is low, some unloading may take place between the frames to effect the effective increase in the capacity of the buffer. When the acquisition speed is high and in particular when the time between frame acquisition is minimal, there is not enough time available to unload between frames. Therefore, unloading during loading will enhance the benefits of fast procurement systems.

While the invention has been illustrated in connection with specific equipment, it will be understood that this description is given by way of example only and is not intended to limit the scope of the invention.

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Claims (11)

1. Buffer memory device for use in. image acquisition systems for temporarily storing images acquired by the system, comprising means for loading the buffer memory device at a rate R1, a long-term memory device for holding the images, and means for unloading the buffer memory device while the image is loaded therein . The buffer memory device of claim 1, wherein the system obtains the images at a high speed. The buffer memory device according to claim 2, wherein the loading speed R1 is at least 12.5 frames per second. The buffer memory device according to claim 3, wherein the unload rate R2 is less than R1. The buffer memory device according to claim 2, wherein the loading rate R1 is at least 25 frames per second. The buffer memory device according to claim 5, 20, wherein the unload rate R2 is at least 12.5 frames per second. . 7. A method of using a buffer memory in conjunction with a permanent memory in subtractive image acquisition systems, the method comprising the steps of obtaining an image, loading the obtained image into a buffer memory at a rate R1, unloading the image. buffer memory to transfer the image in a permanent memory at a rate R2, the unloading taking place during the loading. 8. The method of claim 7, wherein the step of obtaining is at a high speed. The method of claim 8, wherein the rate R1 is at least 12.5 frames per second. The method of claim 8, wherein the speed R2 is at least less than the speed R1. The method of claim 10, wherein the rate R1 is at least 25 frames per second and the rate R2 is at least 12.5 frames per second. ******* 8401215