Direction instructing apparatus direction estimating apparatus and a computer-readable storage medium containing a program for the same stored thereon

• US 6,377,241 B1
• Filed: 04/21/1999
• Issued: 04/23/2002
• Est. Priority Date: 01/21/1999
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Funatsu, Eiichi, Kage, Hiroshi
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): NGUYEN, KIMNHUNG T
• Application Number:
  US09/295,412
• Time in Patent Office: 1,098 Days
• Field of Search: 345/156, 345/157, 345/158, 348/207
• US Class Current: 345/158
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors

Abstract

A direction instructing apparatus includes an image inputting section for inputting data for a two-dimensional image picked up with an image sensor having an image processing function, a projection computing section for computing projections for the two-dimensional image as a whole in directions according to the data inputted into the image inputting section, a movement computing section for computing a one-dimensional movement vector for each projection according to the projection computed in the projection computing section, and a direction estimating section for estimating a two-dimensional movement vector for the two-dimensional image according to the one-dimensional movement vector computed in the movement computing section.

Claims

1. A direction instructing apparatus comprising:

an image inputting unit for inputting data for a two-dimensional image obtained by an image sensor, wherein the two-dimensional image comprises an array of pixels, each pixel having a value related to brightness of the pixel;

a projection computing unit for computing projections in a plurality of directions for the two-dimensional image, wherein the projection computing unit computes the projections for each of the plurality of directions as a plurality of sums of the values of the pixels along each of a plurality of lines parallel to each of the directions;

a movement computing unit for computing a one-dimensional movement vector for each of the projections computed by said projection computing unit; and

a direction estimating unit for estimating a two-dimensional movement vector for the two-dimensional image according to the one-dimensional movement vectors computed by said movement computing unit.

2. The direction instructing apparatus according to claim 1 comprising:

a coordinate updating unit for updating positional information representing coordinates according to the two-dimensional movement vector estimated by said direction estimating unit; and

a coordinate displaying unit for displaying a position on a screen according to the positional information.

3. A direction instructing apparatus comprising:

a projection outputting unit for outputting projections, according to data for a two-dimensional image obtained by an image sensor having an image processing function, for the two-dimensional image in a plurality of directions, wherein the two-dimensional image comprises an array of pixels, each pixel having a value related to brightness of the pixel, and the projection outputting unit produces the projections for each of the plurality of directions as a plurality of sums of the values of the pixels along each of a plurality of lines parallel to each of the directions;

a movement computing unit for computing a one-dimensional movement vector for each of the projections outputted from said projection outputting unit; and

a direction estimating unit for estimating a two-dimensional movement vector for the two-dimensional image according to the one-dimensional movement vectors computed by said movement computing unit.

4. The direction instructing apparatus according to claim 3, wherein said projection outputting unit further computes a difference between a projection output at a current point of time and a projection output at a previous point of time, and said movement computing unit computes a one-dimensional movement vector for each projection according to the difference.

5. The direction instructing apparatus according to claim 3 wherein said projection outputting unit is a semiconductor integrated circuit outputting one of projections of the two-dimensional image in an plurality of directions and a difference between a projection output at a current point of time and a projection output at a previous point of time.

6. The direction instructing apparatus according to claim 3 further comprising:

a coordinate updating unit for updating positional information representing coordinates according to the two-dimensional movement vector estimated by said direction estimating unit; and

a coordinate displaying unit for displaying a position on a screen according to the positional information.

7. A direction estimating method for a direction instructing apparatus estimating a direction of movement in a two-dimensional image picked up with an image sensor, the two-dimensional image comprising an array of pixels, each pixel having a value related to brightness of the pixel, the method comprising:

computing projections for the two-dimensional image for each of a plurality of directions by summing the value of the pixels along each of a plurality of lines parallel to each of the directions;

computing a difference between a projection output at a current point of time and a projection output at a previous point of time according to the projections of the two-dimensional image in a plurality of directions and computing a one-dimensional movement vector for each projection according to the difference; and

estimating a two-dimensional movement vector of the two-dimensional image by synthesizing the one-dimensional movement vectors.

8. The direction estimating method for a direction instructing apparatus according to claim 7 wherein, in computing a difference,

when a projection output at a position at a current point of time has not changed from a projection output at the position at a previous point of time, or when the projection output at a position at a current point of time has changed from a projection output at the position at a previous point of time, the current point of time or the previous point of time is selected as a reference point of time, and, where two adjacent projections at the reference point of time are identical, a direction is not estimated;

when a difference between a projection output at a position at a current point of time and a projection output at the position at a previous point of time is positive, a direction is estimated for a smaller one of the two adjacent projections at the previous point of time;

when a difference between a projection output at a position at a current point of time and a projection output at the position at a previous point of time is negative, a direction is estimated for a larger one of the two adjacent projections at the previous point of time; and

one-dimensional movement vectors are computed after directions are estimated at all positions.