Browse Prior Art Database

Inter-Pel Distance Representation of Image Data

IP.com Disclosure Number: IPCOM000116732D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 170K

Publishing Venue

IBM

Related People

Narasimha, MS: AUTHOR [+3]

Abstract

Segmentation is the first step in the machine recognition of handwritten amounts in personal checks and fields within business forms. Its objective is to separate the individual characters making up the field from each other and from other background data such as lines, boxes and other extraneous markings which might appear on the document. Segmentation algorithms that process black/white image data on byte oriented machines incur added logical and computational complexity in tasks such as setting up mask bytes to test individual image pels and in following features which cross byte boundaries. One way in which this problem has been addressed is to transform the image into a one byte per pel representation.

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Inter-Pel Distance Representation of Image Data

      Segmentation is the first step in the machine recognition of
handwritten amounts in personal checks and fields within business
forms.  Its objective is to separate the individual characters making
up the field from each other and from other background data such as
lines, boxes and other extraneous markings which might appear on the
document.  Segmentation algorithms that process black/white image
data on byte oriented machines incur added logical and computational
complexity in tasks such as setting up mask bytes to test individual
image pels and in following features which cross byte boundaries.
One way in which this problem has been addressed is to transform the
image into a one byte per pel representation.  This disclosure
describes a transformation which is equivalent in computational
complexity to the basic one byte per pel transform but captures
significantly more information about the global structure of the
image.  This additional information can then be used to make the
segmentation and recognition processes substantially less complicated
and more efficient.

      Disclosed is a representation for black/white image data that
provides significantly more information about the global structure of
a black/white image than the "off-on" representation typically used
in image processing.  The representation is useful in feature
location, segmentation, and recognition applications.  It may be
derived from single bit per pel image data either by special purpose
hardware or by the software procedure outlined below.

      The inter-pel distance transformation represents a black/white
image as a three dimensional array.  In this array, the value of
    array(row, column, direction)
  is the distance from the pel located at position "row" and "column"
to the nearest opposite colored pel in the specified "direction".
The number of directions used in the transformation may vary.  For a
simple segmentation problem {left, right} may suffice.  For a more
complicated segmentation problem it may be desirable to compute
{left, right, up, down}.  In recognition applications diagonal
measures may be required as well.

      It is also necessary to have implicit in the representation
whether an image pel is white (background) or black (foreground).
Either one bit may be reserved as a "color" bit, or a convention may
be adopted that a negative distance value implies that the associated
pel is of a specific color.

      The inter-pel distance transformation is illustrated in the
Figure.  An 8-bit representation is used for distance measures.  The
high order bit is reserved and a value of 1 indicates that the
associated pel is black.  The tables show the contents of a four
direction {right, left, down, up} transform.  The image data
represented are the digits "7 1" written in approximately one half
inch high script and digitized at a resolution of 24 pels per inch.
...