公开(公告)号：EP0079333A4

公开(公告)日：1987-07-06

申请号：EP81901825

申请日：1981-03-30

Applicant: IBM

Inventor： LANGDON GLEN GEORGE JR ,  RISSANEN JORMA JOHANNES

IPC: H03M7/40

CPC classification number: H03M7/4006

Abstract: A method and apparatus for recursively generating an arithmetically compressed binary number stream responsive to the binary string from conditional sources. Throughput is increased by reducing the number of operations required to encode each binary symbol so that only a single shift of k bits is required upon receipt of each least-probable symbol or an "add time", followed by a decision and a one-bit shift in response to each most-probable symbol encoding. The concurrent augmentation of the compressed stream and an internal variable involves only the function of a probability interval estimate of the most-probable symbol, and not upon the past encoding state of either variable (2 , 49, 63, C, T). Each binary symbol may be recovered by subtracting 2 from the q-most-significant bits of the compressed stream and testing the leading bit of the difference.

公开(公告)号：AU7836687A

公开(公告)日：1988-03-17

申请号：AU7836687

申请日：1987-09-14

Applicant: IBM

Inventor： LANGDON GLEN GEORGE JR ,  PENNEBAKER WILLIAM BOONE ,  MITCHELL JOAN LAVENE ,  RISSANEN JORMA JOHANNES

IPC: G06T9/00 ,  H03M7/40 ,  G06F5/00 ,  H03M7/30

公开(公告)号：AU600972B2

公开(公告)日：1990-08-30

申请号：AU7836687

申请日：1987-09-14

Applicant: IBM

Inventor： LANGDON GLEN GEORGE JR ,  PENNEBAKER WILLIAM BOONE ,  MITCHELL JOAN LAVERNE ,  RISSANEN JORMA JOHANNES

IPC: G06T9/00 ,  H03M7/40 ,  G06F5/00 ,  H03M7/30

公开(公告)号：AU3829278A

公开(公告)日：1980-01-31

申请号：AU3829278

申请日：1978-07-24

Applicant: IBM

Inventor： CASEY RICHARD GEORGE ,  LANGDON GLEN GEORGE JR ,  MANTEY PATRICK EDWARD ,  WILLIAMS ROBIN

IPC: G06F3/02 ,  G06F3/033 ,  G06F3/041 ,  G06F3/048 ,  G06F3/14 ,  G09G5/08 ,  G06F3/00 ,  G06K9/10

Abstract: There is disclosed a method and means for increasing the positional accuracy of operator controlled cursors engaged in the digitized encoding of graphic information such as line drawings. The method steps comprise those of digitizing the instantaneous contact position between the cursor and the data entry surface as reference coordinates; detecting any segment of a colored object upon the surface within a predetermined area about the cursor; ascertaining the location within the area of the centroid or the like of the detected segment; and digitizing said ascertained location as a displacement from the reference coordinates. Apparatus for practicing the method comprises an independently actuable cursor formed from a position encoder and an image scanner, the scanner generating a Boolean coded array of points counterpart to a preselected surface area. The scanned array is first buffered and then used to actuate an operator viewable LED display of the scanned array on one hand and said array is sent to a CPU on the other hand. In turn, the CPU calculates the coordinates of the centroid of that array area of contiguous points having the same designated Boolean (color) 0 or 1 value. Signals representing the calculated coordinates generated by the CPU then cause the LED display to differentially indicate the calculated centroid location to the operator such as by way of a flashing display element.