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Storage of Type Fonts for in House Publishing Disclosure Number: IPCOM000087177D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 38K

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Stucki, P: AUTHOR


A new concept for the efficient storage of type-fonts is described.

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Storage of Type Fonts for in House Publishing

A new concept for the efficient storage of type-fonts is described.

In certain data processing systems, such as an in-house publishing system, the storage required for type-fonts represents a substantial cost. To reduce the storage requirement, it is proposed to store specific features of the skeleton line of each individual character rather than its compressed raster-scanned representation. To regain a raster representation of the character, the two- dimensional representation of the skeleton line is Fourier transformed, low-pass filtered, reconstructed and thresholded. In practice, this procedure can be simplified and approximated using straight forward digital signal processing techniques in the picture plane. The saving in storage space is substantial when compared to existing type-font compression techniques.

The reconstruction of skeleton lines into their corresponding raster format involves the following signal processing steps:.
1) The skeleton line originally described by a certain


of coordinate pairs is embedded in an array f(x,y).

The dimension of x and y being N=2/n/, n=integer.
2) The array f(x,y) is subjected to a digital Fourier


to obtain its frequency representation F(u,v).

(Image Omitted)

F(u,v) = A(u,v)exp[j phi (u,v)], where

A(u,v) = IF(u,v)l and phi (u,v) = arg [F(u,v)].
3) The frequency representation F(u,v) is multiplied with

a real

or complex low-pass filter function S(u,v). A typical

low-pass filter function being of symmetric rotation

raised cos-type shape and defined as

S(u,v) = 1 over 2 (1+cos pi over 2f(T) square root

u/2/ + v/2/) for u < 2f(T) and v < 2f(T) and

S(u,v) = 0 for u > or = 2f(T) and v > or = 2f(T).

(Fig. 3).

The filtere...