MOUSE WITH SLIP AND ROTATION COMPENSATION

TITLE: MOUSE WITH SLIP AND ROTATION COMPENSATION INVENTORS: ANTHONY BRENT NELSON STEPHEN JOHN GRAHAM A mouse for use with a computer for tracing and digitizing traces on a two dimensional surface has slip and rotation compensation. A second ball is provided with a least one counter capable of encoding X and Y direction movement of the mouse. A first ball includes an X direction counter and a Y direction counter. Appropriate software or hardware compensates for most slip and rotation from discrepancies between the X, Y direction motion of the second ball and the X, Y direction motion of the first ball. Slip and rotation discrepancies between the two balls may be accounted for. In another embodiment, a third ball with a least one counter provides additional information to account for substantially all slip and rotation discrepancies between the first, second and third balls. The mouse is provided with a line of sight indicator or cross hair so that accurate positions may be achieved by sight. The three balls are preferably placed at unequal spacings from the line of sight indicator and should not be co-linear. TITLE: MOUSE WITH SLIP AND ROTATION COMPENSATION INVENTORS: ANTHONY BRENT NELSON STEPHEN JOHN GRAHAM A mouse for use with a computer for tracing and digitizing traces on a two dimensional surface has slip and rotation compensation. A second ball is provided with a least one counter capable of encoding X and Y direction movement of the mouse. A first ball includes an X direction counter and a Y direction counter. Appropriate software or hardware compensates for most slip and rotation from discrepancies between the X, Y direction motion of the second ball and the X, Y direction motion of the first ball. Slip and rotation discrepancies between the two balls may be accounted for. In another embodiment, a third ball with a least one counter provides additional information to account for substantially all slip and rotation discrepancies between the first, second and third balls. The mouse is provided with a line of sight indicator or cross hair so that accurate positions may be achieved by sight. The three balls are preferably placed at unequal spacings from the line of sight indicator and should not be co-linear.