Plotter including a display control for generating and supplying image data for use by a digital display device to control a state of one or more pixels

Patent metadata

Field	Value
Publication number	US-9697801-B2
Application number	US-201414492429-A
Country	US
Kind code	B2
Filing date	Sep 22, 2014
Priority date	Mar 22, 2012
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

The present invention relates to a digital display plotter for plotting images on a digital display device 18 . A cursive imagery generator 12 generates imagery inputs at a plurality of respective update phases during a refresh period of the display device. A control 20 for the display device activates selected pixels of the digital display device in response to respective said imagery inputs, activation being controlled subsequent to each update phase during a refresh period. An input store 14, 16 associates each cursively generated imagery input with an update phase that the imagery input was generated during a refresh period. The control 20 is responsive to the input store and configured to deactivate the selected pixels activated in response to each imagery input dependent on the associated update phase of each imagery input.

First claim

What is claimed is:

1. A plotter for a digital display device, the plotter comprising:
a display control configured:
upon receipt via an input operatively coupled to the display control, at a first update phase within a first image refresh period, of a first imagery input defining activation of a selected pixel representing at least a first portion of an image to be displayed, to store the first imagery input in a first image buffer;
to output, to the digital display device, image data corresponding to the first imagery input as stored in the first image buffer for setting a state of the selected pixel during the first update phase within the first image refresh period, thereby causing the digital display device to display at least a portion of the image represented by the first imagery input;
upon receipt via the input, at a second update phase within the first image refresh period, of a second imagery input defining activation of the selected pixel representing at least a second portion of the image to be displayed, to store the second imagery input in the first image buffer;
to output, to the digital display device, image data corresponding to the second imagery input as stored in the first image buffer for setting the state of the selected pixel during the second update phase within the first image refresh period as stored in the first image buffer mixed with the image data corresponding to the first imagery input as stored in the first image buffer, thereby causing the digital display device to display at least a portion of the image represented by the first and second imagery inputs;
upon receipt via the input, at a first update phase within a second image refresh period subsequent to the first image refresh period, of a third imagery input that does not define activation of the selected pixel, to store the third imagery input in a second image buffer and remove the first imagery input from the first image buffer;
to output image data corresponding to a removal of at least the portion of the image represented by the first imagery input for setting the state of the selected pixel during the first update phase within the second image refresh period, the output image data being mixed with image data corresponding to the second and third imagery inputs as stored in the first and second image buffers, thereby causing the digital display device to display at least a portion of the image represented by the second and third imagery inputs;
upon receipt via the input, at a second update phase within the second image refresh period, of a fourth imagery input that does not define activation of the selected pixel, to store the fourth imagery input in the second image buffer and remove the second imagery input from the first input buffer, and
to output image data corresponding to a removal of at least the portion of the image represented by the second imagery input mixed with image data corresponding to the third and fourth imagery inputs as stored in the second image buffer for setting the state of the selected pixel during the second update phase of the subsequent image refresh period, thereby causing the digital display device to display at least a portion of the image represented by the third and fourth imagery inputs,
wherein the first update phase within the first image refresh period is at a different time than the second update phase within the first image refresh period, and
wherein the first update phase within the second image refresh period is at a different time than the second update phase within the second image refresh period.

2. The plotter as claimed in claim 1 , wherein the display control is arranged to output image data for activating the selected pixel in accordance with any one of a plurality of brightness levels of the received imagery inputs, and the plotter further comprises a brightness store for storing the brightness level of the selected pixel activated by the display control, and wherein the display control is configured to change the brightness level of an activated pixel only while the brightness level to be activated is greater than or equal to the brightness level stored in the brightness store.

3. The plotter as claimed in claim 1 , wherein each of the first, second, third and fourth imagery inputs correspond to respective raster lines in a raster mode of display.

4. The plotter as claimed in claim 3 , wherein each of the first, second, third and fourth imagery inputs received in consecutive image refresh periods correspond to alternate raster lines and the display control is configured to activate the selected pixel such that the raster lines generated during the first image refresh period are interlaced with the raster lines generated during the second image refresh period.

5. The plotter as claimed in claim 1 , wherein the first image buffer includes memory locations corresponding to each of the first and second update phases within the first image refresh period.

6. The plotter as claimed in claim 1 , wherein the image buffer further includes a second image buffer that includes memory locations corresponding to the first and second update phases within the second image refresh period, so as to provide a dual buffer arrangement for adding and removing images from the display device.

7. The plotter as claimed in claim 1 , wherein in response to anti-aliased lines overlapping, a pixel brightness comparison is applied to pixels to be shared by the overlapping anti-aliased lines, so as to set the brightness of the pixel to be displayed to be the greater of the determined pixel brightness for each line and so avoid over-writing a pixel of a given brightness with one of a lower brightness.

8. The plotter as claimed in claim 7 , wherein the determined pixel brightness for each line is added and the resultant pixel brightness is used for display, but limited to maximum brightness for the display.

9. A helmet mounted display, head mounted display or head up display including a plotter as claimed in claim 1 .

10. A method of plotting an image on a digital display device, the method comprising:
upon receipt, at a first update phase within a first image refresh period, of a first imagery input defining activation of a selected pixel representing at least a first portion of an image to be displayed, storing the first imagery input in a first image buffer and outputting, to the digital display device, image data as stored in the first image buffer for setting a state of the selected pixel during the first update phase within the first image refresh period, thereby causing the digital display device to display at least a portion of the image represented by the first imagery input;
upon receipt, at a second update phase within the first image refresh period, of a second imagery input defining activation of the selected pixel representing at least a second portion of the image to be displayed, storing the second imagery input in the first image buffer and outputting, to the digital display device, image data corresponding to the second imagery input as stored in the first image buffer for setting a state of the selected pixel during the second update phase within the first image refresh period mixed with the image data corresponding to the first imagery input, thereby causing the digital display device to display at least a portion of the image represented by the first and second imagery inputs;
upon receipt, at a first update phase within a second image refresh period subsequent to the first image refresh period, of a third imagery input that does not define activation of the selected pixel, storing the third imagery input in a second image buffer and removing the first imagery input from the first image b

Assignees

• Bae Systems Plc

Inventors

• Fulton Robin George

Classifications

• G09G2340/10

  Mixing of images, i.e. displayed pixel being the result of an operation, e.g. adding, on the corresponding input pixels · CPC title

• G09G5/20

  Function-generator circuits, e.g. circle generators {line or curve smoothing circuits} · CPC title

• G09G1/07

  with combined raster scan and calligraphic display · CPC title

• G02B27/017

  Head mounted · CPC title

• G09G3/2007

  Display of intermediate tones · CPC title