Computer graphics processing and selective visual display system – Computer graphic processing system – Plural graphics processors
Reexamination Certificate
1997-11-05
2001-07-03
Tung, Kee M. (Department: 2776)
Computer graphics processing and selective visual display system
Computer graphic processing system
Plural graphics processors
C345S520000
Reexamination Certificate
active
06256049
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a memory management method for entering data into and reading data out of a memory device having a plurality of memory regions.
Such a method for entering data into and reading data out of a storage device can be applied wherever storage devices are used to store data.
However, the use of such advantageously operating methods is particularly important where it is a regular requirement to enter and read out large data volumes.
That is the case, for example, in image processing systems and video systems, etc., specifically and in particular when an image data output unit outputs image data to be displayed on an image display unit such as, for example, video data, in a sequence other than that which has to be delivered to the image display unit for normal display.
That is the case, for example, when the image data output unit sequentially outputs all of the data of an image to be displayed, whereas the image display unit requires the data in a sequence suitable for carrying out an interlacing method.
An MPEG-2 video decoder system according to ISO/IEC standard 13818-2 may be mentioned as a concrete possibility for the use of an advantageously operating memory management method for entering data into and reading data out of a memory device having a plurality of memory regions.
A converting unit must be provided for the purpose of converting the data output by an image data output unit into a sequence suitable for carrying out the interlacing method.
For the purpose of better understanding the structure and function of known converting units, and for the purpose of better understanding the method for operating such converting units according to the invention, an examination will firstly be made of some initial conditions which will be assumed in the following discussion.
It is assumed that the image data output unit outputs image data such as, for example, video data of one line in each case in regular time intervals, with a sequence of output lines proceeding strictly sequentially from an upper end to a lower end of the image to be displayed and therefore not corresponding to a sequence suitable for the interlacing method.
It is further assumed that the image display unit is to be fed the data to be displayed in a sequence suitable for the interlacing method, with the lines to be displayed having to be fed at the same time intervals as lines are output by the image data output unit.
When a sequence suitable for the interlacing method is mentioned, the sequence which is understood is that in which the group of all even lines of an image and the group of all odd lines of the image are transmitted not interlaced with one another but in a temporal sequence. In that process, the group of the even lines yields a first field, and the group of the odd lines yields a second field, with each of the fields naturally including only half of the lines output by the image data output unit per image to be displayed. The frame to be finally output by the image data output unit is obtained on the image display unit by superimposing the associated fields. Two fields are displayed per frame on the image display unit. If the frame frequency is, for example, 25 Hz, the field frequency is 50 Hz.
The simplest known structure of a converting unit for converting the data output by the image data output unit into data suitable for the image display unit includes two digital memories, each of which has a storage capacity that is sufficient to store the data of a complete image to be displayed, that is to say to store the data of a frame.
That converting unit is operated in such a way that the data which are output instantaneously by the image data output unit and are required for displaying the next image are entered into one of the memories, while at the same time the field data to be provided for the image about to be displayed are read out in the appropriate sequence from the other memory.
If such a method is used to represent a frame according to the PAL standard, each of the two digital memories to be provided must have a storage capacity of 4.75 Mbit. Such large storage capacities entail high costs and large devices.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a memory management method, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known methods of this general type in such a way that a converting unit makes do with a memory having a relatively low storage capacity.
With the foregoing and other objects in view there is provided, in accordance with the invention, a memory management method for entering data into and reading data out of a memory device having a plurality of memory regions, which comprises entering data into a memory device and reading data out of the memory device in alternating memory regions of the memory device; and entering the data by writing in a memory region from which data has immediately previously been read out.
Due to the fact that the data last read out are automatically overwritten immediately after being read out by data which are to be newly entered into the storage device, the storage capacity of the storage device is always optimally used, because in this way the storage device is at no time blocked by data which have already been collected and are therefore no longer required.
A method has thus been created which renders it possible to use a converting unit having a relatively low storage capacity.
The reading out of stored data and entering of new data are performed respectively in alternation, that is to say the fact that in the type of memory management according to the invention it is already possible to start reading out the data before an associated total volume of data to be entered into the storage device has been fully stored, means that further processing or displaying of the data can already be started relatively early.
The fact that successive read and write accesses are respectively performed on one and the same memory area further has the effect of a reduced outlay in setting up the respective read and write addresses.
In accordance with another mode of the invention, there is provided a memory management method which comprises entering the data into the memory device in the form of data read out of an image data output unit representing an image to be displayed on an image display unit.
In accordance with a further mode of the invention, there is provided a memory management method which comprises reading out the data stored in the memory device for displaying an image represented by the data on an image display unit.
In accordance with an added mode of the invention, there is provided a memory management method which comprises entering the data in an inscription operation and reading out the data in a readout operation in the form of data representing one line of an image to be shown on an image display unit.
In accordance with an additional mode of the invention, there is provided a memory management method which comprises writing in and reading out the data in the form of video data.
In accordance with yet another mode of the invention, there is provided a memory management method which comprises writing in and reading out the data in the form of video data containing chrominance data and luminance data.
In accordance with a concomitant mode of the invention, there is provided a memory management method which comprises displaying the image on a monitor operating according to an interlacing method as the image display unit.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a memory management method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and metho
Greenberg Laurence A.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
Tung Kee M.
LandOfFree
Memory management method for entering data into and reading... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Memory management method for entering data into and reading..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Memory management method for entering data into and reading... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504345