Ex Parte Holt

Board of Patent Appeals and Interferences

Feb 25, 2002

08825259 (B.P.A.I. Feb. 25, 2002)

1
The opinion in support of the decision being entered today was not written for
publication and is not binding precedent of the Board.
Paper No. 28

UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte JEFFREY J. HOLT
_____________
Appeal No. 2000-0766
Application No. 08/825,259
______________
ON BRIEF
_______________
Before KRASS, RUGGIERO and BARRY, Administrative Patent Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of claims 1-12.
The invention pertains to displaying a line segment on a display having pixels
identified by a two-axis coordinate system. Representative independent claim 1,
illustrative of the invention, is reproduced as follows:
1. An improved device, of the type utilizing a display having pixels
Appeal No. 2000-0766
Application No. 08/825,259
2
identified by a two-axis coordinate system, so that each pixel lies at the
intersection of a coordinate line from each of the axes, for displaying a
line segment having arbitrary endpoints referenced to the same
coordinate system, the display operating under control of a digital
computer, wherein the improvement comprises:
(a) means for determining as a major axis the axis of the
coordinate system with respect to which the line moves most, and for
defining the other one of the axes as the minor axis;
(b) intersection means for identifying the major coordinate lines, if
any, crossing the line segment to be displayed, based only upon the major
axis coordinates of the endpoints of the line segment and
(c) pixel selection means for, with respect to each crossing found
by the intersection means, selecting for display a pixel that both (i) lies on
the major axis coordinate line at the crossing and (ii) has a minor axis
coordinate that is closest to the line segment.
The examiner relies on the following reference:
Foley et al. (Foley), “Computer Graphics: Principles and Practice, Second
Edition”, pp. 72-79, published by Addison-Wesley Publishing Company
(Nov., 1993).
Claims 1-12 stand rejected under 35 U.S.C. § 103 as unpatentable over Foley.
Reference is made to the briefs and answer for the respective positions of
appellant and the examiner.
OPINION
Appeal No. 2000-0766
Application No. 08/825,259
3
We REVERSE.
Each of the independent claims has a paragraph (b) which requires an
identification of the major coordinate lines (if there are any) crossing the line segment to
be displayed and that this identification is “based only upon the major axis coordinates
of the endpoints of the line segment” [emphasis added]. Moreover, independent claim
11 further narrows this to make it clearer that this identification is performed “prior to
selecting any pixel for display of the line segment.”
In applying Foley to the instant claimed invention, the examiner admits that Foley
does not explicitly disclose identifying the major coordinate lines, crossing the line
segment to be displayed, based only upon the major axis coordinates of the endpoints
of the line segment. However, the examiner contends, at page 4 of the final rejection
[Paper No. 18], that only the major coordinate lines crossing the line segment are
identified, based only upon the major axis coordinates of the endpoints of the line
segment in Foley because Foley “shows finding the next major coordinate line crossing
(i.e., intersection), by using the major coordinate line and adding the slope (on page 74,
first paragraph), thus not depending on the minor axis coordinate” [emphasis ours].
The trouble with the examiner’s reasoning is that by employing the slope of the
Appeal No. 2000-0766
Application No. 08/825,259
4
line segment in determining the intersection of the line segment with a major coordinate
line, Foley has, indeed, based the determination, not only upon the major axis
coordinates, as claimed, but also on the slope of the line segment.
While Foley takes one x-value at a time and computes a corresponding y-value,
based on slope, prior to moving on to the next x-value, the instant claimed invention
identifies all of the major axis values between the endpoints of the line segment before
determining any of the minor axis values. As soon as Foley makes a preliminary
calculation of slope, the minor axis coordinates are invoked because the slope gives a
minor axis value for each and every major axis value. In contrast, the instant claims
require using only the major axis coordinates of the endpoints and this must be done
prior to identification of the major axes crossing the line segment.
We find that, as disclosed and argued by appellant, the claim language, “based
only upon the major axis coordinates of the endpoints of the line segment” means that
the identification of the major coordinate lines, if any, crossing the line segment to be
displayed may not be based, in any part, or in any way, on a previous calculation of the
slope. The identification must be based solely on the major axis coordinates of the
endpoints of the line segments. Thus, if the major axis is the x-axis and the line
Appeal No. 2000-0766
Application No. 08/825,259
5
segment runs between x=1.5 and x=5.5, based on these two endpoints, the major
coordinate lines will be at x=2, x=3, x=4 and x=5. The identification is based on
identifying the integer values of the major coordinates between the endpoints No slope
is previously calculated or used in any way to obtain these major coordinate lines
crossing the line segment. No values of the minor coordinate axis (in this case, the y-
axis values) are employed in any manner to obtain the major coordinate lines crossing
the line segment. Our decision herein is based on this interpretation, a reasonable
interpretation urged by appellant.
Since Foley’s line segment display relies on the slope of the line segment (e.g.,
see page 73, paragraph 3.2.1) in order to find the next major coordinate value, by
definition, this depends on minor axis coordinates since the slope is the difference
between two minor axis coordinates divided by the difference between two major axis
coordinates. Since Foley bases identification of major coordinate lines, at least in part,
on minor axis coordinates, Foley does not meet, nor make obvious, the instant claimed
subject matter.
Appeal No. 2000-0766
Application No. 08/825,259
6
The examiner’s decision rejecting claims 1-12 under 35 U.S.C. § 103 is
reversed.
REVERSED
ERROL A. KRASS )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
JOSEPH F. RUGGIERO ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
LANCE LEONARD BARRY )
Administrative Patent Judge )
eak/vsh
Appeal No. 2000-0766
Application No. 08/825,259
7
ROBERT GROOVER
17000 PRESTON RD., #230
DALLAS, TX 75248