Browse Prior Art Database

Display Data Compression

IP.com Disclosure Number: IPCOM000078410D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 48K

Publishing Venue

IBM

Related People

Appel, A: AUTHOR [+2]

Abstract

In high-density displays of information, generally, much more information is generated than is required. In addition to the inefficiency resulting from the latter, an overabundance of information also tends to obscure detail.

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Display Data Compression

In high-density displays of information, generally, much more information is generated than is required. In addition to the inefficiency resulting from the latter, an overabundance of information also tends to obscure detail.

There is described herein a process which effectively eliminates the bulk of the redundant, i.e., unrequired information, the process employing a raster encoding and decoding technique. In addition, the process also provides controls for clipping and resolution selection.

The described process, i.e., raster encoding and decoding, is easily controllable and provides a general method for graphic data compression and presentation on an imaging device. The essential elements of the process are illustrated in Figs. 1, 2 and 3. In the carrying out of the process, an area in main store, suitably termed the main store image map, which represents the resolution of the imaging device, is reserved. The main store image map can represent the resolution on a bit-for-bit basis or a group of bits to convey intensity or color. Fig. 1 illustrates the main store image map. The map comprises; 1) bit-for-bit basis: if there is assumed a 1024x1024 bit resolution, for example; y,1 > 1024 x,1 > 32 in FIG. 1. 2) bit for i bit basis; 1024x1024 bit resolution; i-1 > bits of intensity/color information y,1 > 1024 x,1 > (i*1024)/32 in Fig. 1.

The first phase of the process is the raster encoding phase. In this phase, normal vector or point plotting request made to an imaging device is intercepted by the following process. Raster Encoding PLOT VI (IX,IY,I) y = IY + 1; (IY, Phi > 1023) x = IX/32+1; (Ix, Phi > 1023) IBIT = (IX/32)(R) + 1; (the remainder) y locates the row x locates the column IBIT locates the bit within the word (for 360/370 case 32 bits/word). Then a raster location may be stored. I > defines the intensity or color of the data. For intensity/color information x is calculated in the following manner: x = (IX*(total bits) )/32 + 1 IBIT = (IX*(total bits)/32)(R) where
(R) signifies the remainder; and where total bits' represents the number of bits used to represent the point and the intensity or color information, e.g., 4 bits would represent: ON/OFF bit for the point and 3 bits for intensity values 0-7.

The latter raster encoding process records on the main store image map those raster coordinates which are being plotted, and the intensity or color code associated w...