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Memory Architecture Supporting Multiple Image Formats

IP.com Disclosure Number: IPCOM000034315D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 5 page(s) / 131K

Publishing Venue

IBM

Related People

Flurry, GA: AUTHOR [+3]

Abstract

A memory architecture is described in which a single physical array can be used to store and retrieve images of various formats. The images can also be of varying sizes. Changing to another image format is accomplished by simply setting a few mode bits. This memory architecture also allows easy access through a secondary memory port to provide video scan line data to a CRT monitor. This memory architecture allows the user to store and retrieve video images that employ various compression techniques giving rise to images of varying sizes. All images are stored either in a compressed or uncompressed rectangular form. This method allows for easy access of the image for windowing, panning, or moving any portions of the image, and it provides easy video output scanning and reconstruction to a CRT monitor. Fig.

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Memory Architecture Supporting Multiple Image Formats

A memory architecture is described in which a single physical array can be used to store and retrieve images of various formats.

The images can also be of varying sizes. Changing to another image format is accomplished by simply setting a few mode bits. This memory architecture also allows easy access through a secondary memory port to provide video scan line data to a CRT monitor. This memory architecture allows the user to store and retrieve video images that employ various compression techniques giving rise to images of varying sizes. All images are stored either in a compressed or uncompressed rectangular form. This method allows for easy access of the image for windowing, panning, or moving any portions of the image, and it provides easy video output scanning and reconstruction to a CRT monitor. Fig. 1 shows some of the types of image formats which are used in this system.

(Image Omitted)

The outline of the images shown in Fig. 1 represent the relative sizes of the stored image information. The memory array, as shown in Fig. 4, is large enough to hold a 1024X512X8 bit/pel uncompressed image or a 512X512X16 uncompressed image. The scope of the discussion is limited to cover image sizes which can drive a 640X480 CRT monitor. This uncompressed image type is shown by the first box in Fig. 1.

The second two image outlines are for horizontally compressed images.

This means that every other pel is removed from the original uncompressed image, and the compressed image is half as wide as the original. Notice that the third image has 16 vs. 8 bits/pel, requiring it to be twice as wide as the second image. So this image occupies the same amount of space as the 8-bit uncompressed image. Figs. 2 and 3 illustrate storage of images in 8-and 16-bit/pel mode.

(Image Omitted)

The two double diagonal grid compressed images contain only 1/4 of the original number of pels. Here all the odd scan lines are eliminated as well as every other pel in the even scan lines. The last block in Fig. 1 is a vertically compressed image; here all the odd scan lines are removed so the image is half the original size. Fig. 2 shows how an 8 bit/pel image is stored in the memory arrays. The square outlines represent a memory unit as shown in Fig. 5. The first number within the box in Fig. 2 indicates the scan line, and the second number indicates the pel on that scan line. Outside of the memory unit boxes is labeled the corresponding row and column address for the memory units. Fig. 3 shows how a 16-bit/pel image is stored. Notice that there is only enough room in the array to store a 16-bit/pel image if it is horizontally compressed or is double diagonal grid compressed. The H and L indicate the high and low 8 bits of the pel. A physical diagram

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of the memory architecture is shown in Fig. 4. Block 1 represents the memory array. The memory array is composed of 4-1 Megabit Video RAMSs such as t...