Image analysis – Pattern recognition – On-line recognition of handwritten characters
Reexamination Certificate
1999-09-23
2003-09-23
Dastouri, Mehrdad (Department: 2623)
Image analysis
Pattern recognition
On-line recognition of handwritten characters
C382S120000, C382S121000, C382S122000, C178S019010, C345S173000
Reexamination Certificate
active
06625314
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic pen device and a character recognition method employing the same, and more particularly, it relates to an electronic pen device allowing pen-based character entry and a character recognition method employing the same.
2. Description of the Prior Art
In general, a method of detecting the coordinates of a character handwritten on a tablet with a pen and recognizing the character on the basis of a detection result is widely known as a method of pen-based character entry. However, this method has only limited uses due to the requirement for a large-sized member, i.e., the tablet.
In this regard, various devices for inputting coordinates without employing tablets are recently proposed. For example, a pen-type input device inputting coordinates on the basis of a detection result in a ball rotation sensor provided on a pen point is proposed. For example, Japanese Patent Laying-Open No. 7-281827 (1995) discloses such an input device employing a ball rotation sensor.
FIG. 10
is a perspective view showing the appearance of the conventional input device
140
employing a ball rotation sensor disclosed in Japanese Patent Laying-Open No. 7-281827, and
FIG. 11
is a sectional view showing the internal structure of the conventional input device
140
employing a ball rotation sensor shown in FIG.
10
.
FIG. 12
is a perspective view showing the structure of a rotation detection part of the conventional input device
140
employing a ball rotation sensor shown in
FIG. 10
, and
FIG. 13
is a perspective view for illustrating a busy condition of the conventional input device
140
employing a ball rotation sensor shown in FIG.
10
.
Referring to
FIGS. 10 and 11
, the conventional input device
140
employing a ball rotation sensor includes a substantially pen-shaped body part
110
, a spherical rotator
112
, an annular ring
136
, a rotation detection part
114
, an electric circuit part
132
, a manual switch
134
and a cable
142
. The body part
110
is in the form of a cylinder having an open lower end. The rotation detection part
114
and the electric circuit part
132
are arranged in the body part
110
. The rotation detection part
114
rotatably holds the spherical rotator
112
and detects the direction and the amount of rotation of the spherical rotator
112
. The annular ring
136
has a function of fixing the electric circuit part
132
and the rotation detection part
114
to the body part
110
. The electric circuit part
132
amplifies outputs detected by the rotation detection part
114
and transmits the amplified outputs to a computer. The manual switch
134
is provided on the side surface of the body part
110
, and employed for defining input coordinates.
With reference to
FIG. 12
, the detailed structure of the rotation detection part
114
is now described. The rotation detection part
114
is provided with a cylindrical case
116
. A small ball
118
is set in the case
116
to rotate in correspondence to rotation of the spherical rotator
112
. The small ball
118
is in contact with rollers
120
and
122
having rotation axes intersecting each other at an angle of 90°. Slit disks
124
and
126
having a number of radially extending slits formed at regular intervals are fixed to the rollers
120
and
122
respectively. An optical sensor
128
detects the direction and the amount of rotation of the slit disk
124
, and an optical sensor
130
detects the direction and the amount of rotation of the slit disk
126
.
Each of the optical sensors
128
and
130
includes two photodetectors arranged with a phase difference of 90° with respect to the interval between the slits and a light emitting device opposed to the two photodetectors through the slits.
In operation, the two photodetectors provided on each of the optical sensors
128
and
130
detect light passing through the slits respectively for determining the directions of rotation of the rollers
120
and
122
from the phase difference between the detected signals. The amounts of rotation of the slit disks
124
and
126
are obtained by accumulating the numbers of output pulses from the photodetectors. Further, composition of vectors of the amounts of rotation obtained by the two optical sensors
128
and
130
is performed thereby obtaining the directions and the amounts of rotation of the small ball
118
and the spherical rotator
112
.
The conventional input device
140
employing a ball rotation sensor having the aforementioned structure is connected to a computer mainframe
144
through the cable
142
as shown in FIG.
13
. The computer mainframe
114
includes a display part
146
and a keyboard
148
. When the input device
140
is in use, the display part
146
displays a cursor (pointer)
150
. This cursor
150
moves following rotation of the spherical rotator
112
of the input device
140
. More specifically, the cursor
150
moves in the same direction as the direction of rotation of the spherical rotator
112
by a distance proportionate to the amount of rotation of the spherical rotator
112
.
In order to input a character with the input device
140
, the spherical rotator
112
provided on the pen point of the input device
140
is brought into an entry plane (plane for writing characters or the like) for writing a prescribed character with the input device
140
, and the switch
134
is pressed so that the written character is input in the computer mainframe
144
.
In the aforementioned conventional input device
140
employing a ball rotation sensor, however, the spherical rotator
112
, which rotates when the pen point is in contact with the entry plane (contact state), does not rotate when the pen point separates from the entry plane (noncontact state). Therefore, a locus in the noncontact state cannot be detected. More specifically, when a character “+” is written as shown in
FIG. 14
, the locus from end coordinates
161
of the transverse line to start coordinates
162
of the vertical line cannot be detected and hence it is difficult to recognize to which one of those shown in
FIGS. 15
to
17
this character belongs. In other words, it is difficult for the conventional input device
140
employing a ball rotation sensor to recognize a character, which cannot be written with one stroke, formed by a locus in a contact state and a locus in a noncontact state, although the input device
140
can detect a character, which can be written with one stroke, formed by only a locus in a contact state.
In order to cope with this problem, there has generally been proposed a method of writing a character, which cannot be written with one stroke by a general writing method, with one stroke by a specific writing method without separating a pen point from an entry plane and performing character recognition on the character written with one stroke. Such a method is disclosed in Pilot Handbook (1996 by U.S. Robotics, Inc.), Chapter 2 (Working with Pilot), pp. 22 to 31, for example. In this proposed method, however, a specific way of writing is necessary for writing a character with one stroke, and hence the writer must abandon a familiar way of writing. Consequently, this method imposes a burden on the writer, and readily leads to miswriting. Thus, it is difficult to employ this method.
As another exemplary device for recognizing a character without employing a tablet, a pen-type input device recognizing a character with an acceleration sensor is generally proposed. For example, Japanese Patent Laying-Open No. 6-67799 (1994) discloses such an input device employing an acceleration sensor. The conventional input device employing an acceleration sensor detects both of a locus in a contact state and that in a noncontact state with the acceleration sensor.
FIG. 18
is a perspective view showing the structure of a conventional input device
201
employing acceleration sensors, and
FIG. 19
is a block diagram showing the electrical structure of a signal processing circuit of the conventional i
Armstrong Westerman & Hattori, LLP
Dastouri Mehrdad
Sanyo Electric Co., LTD
LandOfFree
Electronic pen device and character recognition method... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electronic pen device and character recognition method..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronic pen device and character recognition method... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3105263