Method for software scan conversion of target identification data in a general purpose computer

In a process for scan conversion of target identification data based upon polar coordinates to target identification data, based upon rectangular coordinates in a programmable digital computer, wherein said target identification data based on polar coordinates, is supplied to said digital computer and comprises antenna angle (θ), and echo amplitude range (r) data, and said digital computer supplies target identification data based on rectangular coordinates which control (x,y) defined pixels of a viewing area on a monitor display, comprising:

• (a) drawing a plurality of radial lines from an origin, each of which lines is associated with an azimuthal resolution region wherein said radial lines bisect the aggregate group of all radial lines associated with all lower azimuthal resolution regions;
• and
• (b) modifying the drawing of said plurality of radial lines of step (a), by filling in the pixels left unfilled when the drawing of any of said radial lines changes by one pixel in both the x and y dimensions;
• the improvement comprising:
• detecting consecutive polar coordinate target identification data bits which map into the same Cartesian coordinate target identification data bits and mapping said consecutive polar coordinate target identification data bits into said Cartesian coordinate data bits in a single display update.

In a process for scan conversion of target identification data, based upon polar coordinates to target identification data based upon rectangular coordinates in a programmable digital computer, wherein said target identification data based on polar coordinates is supplied to said digital computer and comprises antenna angle (θ), and echo amplitude range (r) data, and said digital computer supplies target identification data based on rectangular coordinates which control (x,y) defined pixels of a viewing area on a monitor display, comprising:

• (a) drawing a plurality of radial lines from an origin, each of which lines is associated with a azimuthal resolution region, wherein said radial lines bisect the aggregate group of all radial lines associated with all lower azimuthal resolution regions;
• (b) modifying the drawing of said plurality of radial lines of step (a) by filling in the pixels left unfilled when the drawing of any of said radial lines changes by one pixel in both the x and y dimensions, and
• (c) performing polar apex removal in order to minimize drawing of redundant pixel displays by:
• 1. determining the resolution region number corresponding to the azimuth number of each of said radial lines;
• and
• 2. using the resolution region number of step (c)(1) to determine the hole-filled x or y range produced by the aggregate radial pattern comprising all radial lines in lower resolution regions,
• the improvement comprising:
• compressing and saving echo amplitude range data of consecutive pulses of target input data up to twice said hole-filled x or y range, in correspondence with said hole-filled range for the current radial line in order to prevent overwriting of said target identification data with non-target identification data when the drawing of consecutive radials overlaps on said display.

In a method of converting and displaying target identification data supplied by one or more analog target identification systems, each of which have separate processors coupled to one or more displays over a digital network wherein each of said systems proceeds by:

• (a) digitizing analog video data and range data;
• (b) digitizing azimuth analog data, which is representative of the azimuth of one or more antennas associated with a particular source of target identification data;
• (c) applying range compression to said digital video data and said digital range data to provide compressed digital video data;
• (d) applying window detection to said range compressed digital video data and said digital azimuth data to provide digital window detected data, and
• (e) transmitting said digital window detected video data over said digital network to said displays and control signals from said displays to said processors for selecting the images to be displayed on said displays;
• and
• the improvement comprising:
• (a) integrating said digital window detected video data into at least one polar data buffer memory with previously stored digital window detected video data;
• (b) extracting stored digital window detected video data from said polar data buffer memory for presentation on said display at an extraction rate that may differ from said integration rate;
• and
• (c) applying a decay rate to modify selected stored digital window detected video data in said polar data buffer memory following extraction of said stored digital window detected video data for presentation on said display.