Computer graphics processing and selective visual display system – Display peripheral interface input device – Cursor mark position control device
Reexamination Certificate
1999-04-21
2002-04-23
Hjerpe, Richard (Department: 2674)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Cursor mark position control device
C345S157000
Reexamination Certificate
active
06377241
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for computing projections of a two-dimensional image, obtained using an image sensor as a whole, in a plurality of directions and estimating the direction of movement from a result of the computing, and to a computer-readable storage medium containing a program for the method.
BACKGROUND OF THE INVENTION
Description is made hereinafter for a direction instructing apparatus based on the conventional technology. For instance, in information equipment such as a personal computer, a pointer displayed on a screen is moved according to the movement of a mouse or the like used as a pointing device. Namely, a pointer displayed on a screen is moved according to, for instance, the direction of movement or the speed of the pointer computed from the coordinates (position) on a screen indicated by the pointer or the like as well as from rotation of a ball incorporated therein.
With the pointing device as described above, use thereof is limited to a space on a desk, namely it is necessary to secure an operational space, and the pointing device can not be operated in a small space such as that in, for instance, a running car. Even when the required space is available, if the space does not have a surface that gives a proper friction or if it has a vertical face (such as a wall surface), the ball in the mouse cannot rotate and the pointer on a screen cannot stably be operated.
To solve the problem as described above, it is conceivable to provide, for instance, an image sensor in a pointing device in order to move in instructing position (a pointer) on a screen to a particular position by computing the direction of movement of the image sensor itself from the movement of an image obtained by the image sensor according to a result of computing. With the method described above, it is possible to stably operate a pointer on a screen even at a surface which does not provide proper friction or on a vertical surface as if the pointer were operated on a desk.
To realize the pointing device as described above, it is necessary to estimate the movement of an image obtained by the image sensor as well as to move the pointer by updating a mouse position or a position (coordinates) of the pointer on the screen according to a result of estimation. As a technical document enabling the processing as described above, there is, for instance, Japanese Patent Laid-Open Publication No. HEI 9-134250 disclosing cursor position control on a video display unit. In the method disclosed in this document, a movement vector included in an image comprising 32×32 pixels is computed by means of correlational operation.
Generally, the resolution movement within one pixel can not be detected, therefore, in order to account for a relatively slow movement which can not be detected at this resolution, it is necessary to raise the resolution of the image itself. Thus, in order to respond to the relatively slow movement as described above in the positional control as disclosed in the technical document above, it is necessary to increase the number of calculations required for a correlational operation for a movement vector and memory capacity of an image buffer according to a resolution shown by N×N pixels.
As described above, with the conventional technology, a cursor or the like on a screen can be controlled by computing a movement vector included in an image consisting of N×N pixels according to an image picked up with an image sensor by means of a correlational operation.
With the conventional technology as described above, however, the number of calculations required for correlational operations for a movement vector increases according to an improvement in the resolution of the image sensor, so that a more expensive CPU is required for high speed operation. Further, capacity of the memory which stores the image data and a result of computing also increases according to an improvement in the resolution of the image sensor, so that a memory with a larger capacity is required. Therefore, with the conventional technology, there occurs the problem that low cost packaging of a pointing device is difficult.
SUMMARY OF THE INVENTION
It is an object of the present invention to obtain a direction instruction apparatus which does not require a special operation space and can operate a pointer on a screen, even on a surface which does not provide proper friction or a vertical surface, and also which enables low cost packaging using a low price CPU and a small capacity memory, a direction estimating method applicable for the apparatus, and a computer-readable storage medium containing a program for the method.
With the present invention, from two-dimensional image data obtained with an image sensor, projections of the two-dimensional image as a whole in a plurality of directions are computed, and a one-dimensional movement vector for each projection is computed from the computed projections. Then a two-dimensional movement vector for the two-dimensional image as a whole is estimated from the plurality of one-dimensional movement vectors. As described above, with the direction instructing apparatus, a two-dimensional movement vector is not directly computed from pixel data for a two-dimensional image like in the conventional technology, but at first, projections for a two-dimensional image are computed, and then the two-dimensional movement vector is estimated. More specifically, a two-dimensional movement vector is not computed directly from, for instance, 32×32 (=1024) pixel data, but at first 32 rows+32 columns (=64) projections are computed, and then the two-dimensional movement vector is estimated.
Therefore, in the direction instructing apparatus according to the present invention, a number of data can substantially be reduced and in association with this number of calculations performed by the CPU and a memory capacity for storing data can largely be reduced. In other words, a cheaper CPU and memory can be packaged and a function of a pointing device can be realized with a low cost system. Further, as number of calculations performed by the CPU and a memory capacity for storing the data can largely be reduced, the computing speed can be increased. In addition, where the direction instructing apparatus according to the present invention is used as a mouse, this mouse operates based on recognition of movement by means of image processing, so that it is not necessary to secure any special operating space, and further it is possible to stably operate a pointer on a screen even at a surface which does not provide proper friction or even at a vertical surface.
With the invention, for instance, when a pointer is displayed at a position on a screen, positional information represented by coordinates (positional information for a pointer being currently displayed) is updated according to a two-dimensional movement vector estimated by a direction estimating unit, and the position of the pointer on a screen is moved to the updated coordinate position according to positional information represented by the updated coordinates as well as to a size of the vector (speed of movement). With this configuration, the direction instructing apparatus according to the present invention can realize a mouse which does not require any specific operating space, and further a pointing device pointing a point on a screen used in a conference or during a lecture (corresponding to a conventional type of pen-light or stick) or a pointing device for game operation (used for operation in a shooting game or a game in which a characters are moved) can be realized by using the two-dimensional image and also by utilizing the characteristics that a pointer or the like displayed on the screen can be moved.
With the present invention, from the data for a two-dimensional image obtained with an image sensor, projections for the two-dimensional image as a whole in a plurality of directions are automatically outputted, and a one-dimensional movement vector f
Funatsu Eiichi
Kage Hiroshi
Hjerpe Richard
Leydig , Voit & Mayer, Ltd.
Nguyen Kimnhung
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