Telegraphy – Systems – Position coordinate determination for writing
Reexamination Certificate
2000-09-05
2003-05-27
Shalwala, Bipin (Department: 2673)
Telegraphy
Systems
Position coordinate determination for writing
C178S018030, C178S018040, C178S018050, C178S018060, C178S018070, C178S019010, C178S019020, C178S019030, C345S156000, C345S158000, C345S162000, C345S166000, C345S173000, C345S207000, C250S227110, C250S227140, C340S555000, C340S556000, C341S005000
Reexamination Certificate
active
06570103
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Japanese patent application Nos. JPAP11-249866 filed on Sep. 3, 1999 and JPAP11-322473 filed on Nov. 12, 1999 in the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.
BACKGROUND
1. Field
The present invention relates to a method and apparatus for coordinate inputting, and more particularly to a method and apparatus for coordinate inputting that is capable of effectively using a laser ray.
2. Description of the Related Arts
A coordinate input apparatus capable of optic ally detecting an obstacle such as a finger or a pen has been widely used in an electronic copyboard, a video conference system, and so forth. One example of the coordinate input apparatus is described in U.S. Pat. No. 5,241,139 issued on Aug. 31, 1993 to Gungl et al.
In general, the coordinate input apparatus is configured to detect a coordinate of a position of an obstacle such as a finger or a pen (i.e., a stylus) when the obstacle is placed in an input region and blocks light running in the input region. Therefore, resolution of the coordinate needs to be finer by several orders of magnitude to compare with the size of the obstacle. This becomes more pronounced, particularly in a case where the coordinate input apparatus is installed on a display face of a display unit and a track of the obstacle moving in the input region is displayed on the display face. That is, the resolution of the coordinate is required to be comparable to that of the display unit. But, if such a high resolution is applied to the coordinate, even an edge of an obstacle may be detected as a position of the obstacle. As a result, the position of the obstacle may be displayed with a displacement on the display unit. Also, if such a high resolution is applied to the coordinate, the coordinate input apparatus needs to increase a number of detecting devices in response to an increase of the resolution. In this case, the manufacturing cost of the coordinate input apparatus will be increased.
SUMMARY
The present invention provides a novel coordinate input apparatus. In one example, a novel coordinate input apparatus includes a plurality of light sources, a reflecting member, a plurality of light receiving members, a signal analyzing mechanism, and a coordinate determining mechanism. Each of the plurality of light sources is fixed around a perimeter of a predefined input region at a fixing position different from others and is configured to emit light extending in a deltaic form centered at the fixing position and approximately in parallel to the predefined input region. The reflecting member is fixed around the perimeter of the predefined input region and is configured to recursively reflect the light so that the light returns towards the plurality of light sources. The plurality of light receiving members are fixed around the perimeter of the predefined input region and are configured to receive the light recursively reflected from the reflecting member and to convert the light into an electric signal. The signal analyzing mechanism analyzes the electric signal to detect a position of an obstacle when the obstacle is placed in the input region and blocks the light. The coordinate determining mechanism calculates a center between coordinates of one and the other edges of the obstacle and determines the center as a coordinate of the position of the obstacle in the input region.
The present invention further provides a novel coordinate input apparatus. In one example, a novel coordinate input apparatus includes a plurality of light sources, a reflecting member, a plurality of light receiving members, a signal analyzing mechanism, a memory, and a coordinate determining mechanism. Each of the plurality of is fixed around a perimeter of a predefined input region at a fixing position different from others and is configured to emit light extending in a deltaic form centered at the fixing position and approximately in parallel to the predefined input region. The reflecting member is fixed around the perimeter of the predefined input region and is configured to recursively reflect the light so that the light returns towards the plurality of light sources. The plurality of light receiving members are fixed around the perimeter of the predefined input region and are configured to receive the light recursively reflected from the reflecting member and to convert the light into an electric signal. The signal analyzing mechanism analyzes the electric signal to detect a position of an obstacle when the obstacle is placed in the input region and blocks the light. The memory prestores a first light amount reference and a second light amount reference having a value greater than that of the first light amount reference. The coordinate determining mechanism determines a coordinate of the position of the obstacle placed in the input region based on a plurality of successively-aligned pixels in the electric signal, including at least a focus pixel and pixels immediately previous to and immediately subsequent to the focus pixel, and the first and second light amount references. This determination is performed in the following manners. When each of the immediately previous, focus and immediately subsequent pixels has a brighter value than that of the second light amount reference, a coordinate of the focus pixel is not a coordinate of an edge of the obstacle. When each of the immediately previous and focus pixels has a brighter value than that of the second light amount reference and the immediately subsequent pixel has a darker value that those of the first and second light amount references, the coordinate of the focus pixel is not a coordinate of an edge of the obstacle. When the immediately previous pixel has a brighter value than that of the second light amount reference, when the focus pixel has a darker value that that of the second light amount reference, and when the immediately subsequent pixel has a darker value that those of the first and second light amount references, the coordinate of the focus pixel is a coordinate between a center and a right edge of the obstacle. When the immediately previous pixel has a brighter value than that of the second light amount reference, when the focus pixel has a darker value that that of the first light amount reference, and when the immediately subsequent pixel has a darker value that those of the first and second light amount references, the coordinate of the focus pixel is a coordinate of the center of the obstacle. When the immediately previous pixel has a darker value than those of the first and second light amount references and when each of the focus and immediately subsequent pixels has a brighter value that that of the second light amount reference, the coordinate of the focus pixel is not the coordinate of the center of the obstacle. When the immediately previous pixel has a darker value than those of the first and second light amount references, when the focus pixel has a darker value than that of the second light amount reference, and when the immediately subsequent pixel has a brighter value that that of the second light amount reference, the coordinate of the focus pixel is a coordinate between a left edge and the center of the obstacle. When the immediately previous pixel has a darker value than those of the first and second light amount references, when the focus pixel has a darker value than that of the first light amount reference, and when the immediately subsequent pixel has a brighter value that that of the second light amount reference, the coordinate of the focus pixel is the coordinate of the center of the obstacle. When each of the immediately previous, focus, and immediately subsequent pixels has a darker value than those of the first and second light amount references, the coordinate of the focus pixel is not a coordinate of an edge of the obstacle.
Further, the present invention provides a novel coordinate input apparatus. In one example, a novel coordinate input apparatus inc
Saka Yasuhiko
Takekawa Kenichi
Kovalick Vincent E.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
Shalwala Bipin
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