System for raster imaging with automatic centering and image compression

Apparatus for centering the display of a raster image made up of r sequential lines on a display device which displays a series of sequential frames of n horizontal lines on a raster imaging surface, where r is less than n, each of said frames having a controllable start time, comprising:

• means for establishing the number n of horizontal lines in said frames;
• means for counting the number r of lines in said raster image,
• first circuit means responsive to said counting means for determining one half of the difference between the number of lines n on said imaging surface for a given frame and the number of lines r in said raster image;
• and
• second circuit means for controlling the start time of a subsequent one of said frames based on said determined one-half difference;
• and
• means for beginning the display of said raster image based on said controlled start time of said sequential frames of said n horizontal lines so that said r lines of said raster image are positioned in the vertical center of said raster imaging surface.

A method for centering the display of a raster image made up of r sequential lines on a display device which displays a series of sequential frames of n horizontal lines on a raster imaging surface, where r is less than n, each of said frames having a controllable start time, said method comprising the steps of:

• establishing the number n of horizontal lines in said frames;
• counting the number r of lines in said raster image,
• determining one half of the difference between the number of lines n on said imaging surface for a given frame and the number of lines r in said raster image;
• and
• controlling the start time of a subsequent one of said sequential frames based on said determined one-half difference;
• and
• means for beginning the display of said raster image based on said controlled start time of said sequential frames of said n horizontal lines so that the said r lines of said raster image are located in the vertical center of said raster imaging surface.

A method for producing horizontal centering of an image made up of lines of c columns of raster data on a display device which displays a series of sequential lines made up of v columns on a raster imaging surface, where c is less than v, each said line of v columns having a controllable start time, said method comprising the steps of

• detecting the time of the beginning of the first or the last column, or both, of said c columns of raster data in at least one of said lines;
• controlling the start time of a subsequent one of said lines of said v columns at a time determined by said detected time of said beginning of said first or said last, or both, of said c columns of raster data;
• and
• means for beginning the display of said raster image based on said controlled start time of said one of said lines of said v columns so that said c columns of raster data of said raster image are positioned in the horizontal center of said raster imaging surface.

Apparatus for horizontally centering the display of a raster image made up of lines of a number c of columns of raster data on a raster imaging surface which displays a series of lines made up of a number v of columns, where c is less than v, each of said lines having a controllable start time, comprising:

• means for establishing the number v of columns in at least one of said lines;
• means for counting the number c of columns of raster data in said raster image,
• first circuit means responsive to said counting means for determining one half of the difference between the determined number of columns v on said imaging surface device and the number of columns c of raster data in said raster image;
• second circuit means for controlling the start time of a subsequent one of said lines based on said determined one half difference;
• and
• means for beginning the display of said raster image based on said controlled start time of said one of said lines of said v columns so that said c columns of said raster data of said raster image are positioned in the horizontal center of said raster imaging surface.

A method for simultaneously producing vertical and horizontal centering of a raster image made up of r sequential lines of raster data and c columns of raster data on a display device which displays a series of sequential frames of n horizontal lines of v columns on a raster imaging surface, where r is less than n and c is less than v, each said frame of n lines of va columns having a controllable start time for a frame and having a controllable start time for each of said n lines, said method comprising the steps of

• detecting the times of the beginning of the first or the last line, or both, of said r lines of said raster data and the beginning of the first or last column, or both, of said c columns of raster data in a line in at least one of said images;
• controlling the start time of a subsequent one of said sequential frames of n lines and v columns at a time determined by said detected time of said beginning of said first or said last, or both, of said r lines of raster data;
• controlling the start time for each of said n lines at a time determined by said detected time of said beginning of said first or said last, or both, of said c columns of raster data in a line;
• and
• beginning the display of said raster image based on said controlled start time of said n horizontal lines and said v columns so that said r lines and said c columns of said raster image are positioned in the vertical and horizontal center of said raster imaging surface.

Apparatus for simultaneously producing vertical and horizontal centering of a raster image made up of r sequential lines of raster data and c columns of raster data on a display device which displays a series of sequential frames of n horizontal lines of v columns on a raster imaging surface, where r is less than n and c is less than v, each said frame of n lines of v columns having a controllable start time for a frame and having a controllable start time for each of said n lines, said apparatus comprising:

• means for detecting the times of the beginning of the first or the last line, or both, of said r lines of said raster data and the beginning of the first or last column, or both, of said c columns of raster data in a line in at least one of said images;
• means for controlling the start time of a subsequent one of said sequential frames of n lines and v columns at a time determined by said detected time of said beginning of said first or said last, or both, of said r lines of raster data;
• means for controlling the start time for each of said n lines at a time determined by said detected time of said beginning of said first or said last, or both, of said c columns of raster data in a line;
• and
• means for beginning the display of said raster image based on said controlled start time of said n horizontal lines and said v columns so that said r lines and said c columns of said raster date of said raster image are positioned in the vertical and horizontal center of said raster imaging surface.