Patent ID: 6025829
Filing Date: 2000-02-15
Classification: A61B

Abstract:
In an image generator for use with a video monitor which displays a plurality of scan lines that extend in a scan direction, said image generator being adapted to enable the video monitor to display a line-based image, said image including a pattern comprising a plurality of pattern scan line segments that include pluralities of pixels having brightnesses that are approximately equal and that correspond to respective pattern brightness signal values, and a background comprising a plurality of background scan line segments that include pluralities of pixels having brightnesses that are approximately equal and that correspond to a background brightness signal value, said pattern and background scan line segments being aligned in parallel with one another in a predetermined direction, in combination:pattern storage means for storing the information necessary to display said image, said pattern storage means including:(a.) a one-bit deep frame buffer for storing, on a pixel-by-pixel basis, for each scan line to be displayed on the video monitor, a selection control signal that indicates which pixels are associated with said pattern, and which pixels are associated with said background; and(b.) means for storing, on a line-by-line basis, for each scan line to be displayed on the video monitor, the pattern and background brightness signal values that are to be used to display that scan line, said brightness signal values having a brightness resolution of M-bits;an analog multiplexer having at least two signal inputs, a control input, and an output for connection to a video input of the video monitor;at least two digital to analog converters (DACs) having outputs connected to respective signal inputs of the analog multiplexer;a shift register for shiftably applying a one-bit selection control signal to the control input of the analog multiplexer;processing means, responsive to said pattern storage means, for:(a.) supplying to said DACs, prior to displaying each scan line of the video monitor, the pattern and background brightness signal values that are associated with that scan line; and(b.) supplying to said shift register, prior to displaying each scan line of the video monitor, the selection control signal that is associated with that scan line; andmeans for clocking said shift register to display said image;wherein the scan direction of the video monitor and said predetermined direction are parallel to one another, whereby the video monitor is able to display scan line segments having a brightness resolution of M-bits, even though said frame buffer is a one-bit deep frame buffer.