Browse Prior Art Database

Regridding Method

IP.com Disclosure Number: IPCOM000073657D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 3 page(s) / 58K

Publishing Venue

IBM

Related People

Boberg, CP: AUTHOR [+3]

Abstract

This is a computer-programmable method for causing an arbitrary design or pattern composed of blank (or white) rectangles and filled (or colored) rectangles (or a corresponding pattern of 0 and 1 bits placed geometrically upon a coordinate grid of one mesh to be converted into an equivalent pattern of like elements placed upon a coordinate grid of coarser mesh (having fewer rows and/or fewer columns than the first grid).

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 51% of the total text.

Page 1 of 3

Regridding Method

This is a computer-programmable method for causing an arbitrary design or pattern composed of blank (or white) rectangles and filled (or colored) rectangles (or a corresponding pattern of 0 and 1 bits placed geometrically upon a coordinate grid of one mesh to be converted into an equivalent pattern of like elements placed upon a coordinate grid of coarser mesh (having fewer rows and/or fewer columns than the first grid).

A superposed relationship of the two grids is shown for a specific example in which each row of the "large" grid (i.e., the grid of coarser mesh) is equivalent to 2 1/2 rows of the "small" grid (i.e., the grid of finer mesh), and each column of the large grid is equivalent to 3 1/2 columns of the small grid. In carrying out the grid conversion process, the grid data are handled as though the two grids were in this superposed relationship with a common origin. Effectively, each large grid rectangle (LGR) is scanned to see whether it contains any portion of a filled small grid rectangle (SGR) within its boundary, and if so, a determination is made as to whether the LGR should have a blank or filled status according to the ratio between the blank and filled areas of the various SGR's contained within its boundary, as weighted by any arbitrarily chosen factor.

Explaining this action in terms of the stored binary data, the scanning process senses the presence of all 1 bits stored in the small grid array at positions that are located within the boundary of the LGR presently under consideration, or within the spacing of one small grid row or column next to such boundary. As shown, there may be any of eight different cases of partial overlap between small-grid and large-grid rectangles (cases 1-8) or a case of complete overlap (case 9). For each case, a particular computational routine is followed to determine what portion of this SGR area may be allocated to the LGR under consideration. The LGR is then determined to have a "blank (0) or "filled" (1) status according to the ratio of these accumulated SGR areas to the total LGR area, in comparison with an arbitrarily chosen threshold value.

A specific example of a situation in which regridding may be needed is the problem of converting an outline design drawn upon a fine-mesh graphic input tablet into an equivalent pattern of 1's and 0's placed upon a grid representing by its rows and columns the weft and warp threads of a woven fabric, such grid necessarily being of coarser mesh than that of the graphic input tablet. The boundary points of the various disjoint areas or closed regions of the design are stored as "small grid" data in an outline memory. An equivalent outline now must be entered into a memory array whose grid coordinates are compatible with the rows and columns (i.e., the weft and warp threads) of the fabric in which the design is to be manifested. Described in general terms, the algorithm proceeds as follows:

Each large grid (LG) row is fig...