| CPC H04N 19/186 (2014.11) [G06V 10/56 (2022.01)] | 17 Claims |
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1. A method of generating a compressed data stream from an image comprised of pixels which each have a red, a green and a blue colour value, wherein the compressed data stream is to be fed into a projector scanning a red, a green and a blue light beam across an image area according to a given scan pattern, the light beams being modulated in intensity according to respective red, green and blue colour values in the compressed data stream, the method comprising,
for each sub-interval of a fixed number of sub-intervals which together form a time interval:
extracting, from the image, i) that red colour value that is to be displayed by the red light beam within said sub-interval according to the scan pattern, ii) that green colour value that is to be displayed by the green light beam within said sub-interval according to the scan pattern, and iii) that blue colour value that is to be displayed by the blue light beam within said sub-interval according to the scan pattern, and
appending the extracted red, green and blue colour values to an uncompressed data stream which has a red sub-stream for the extracted red colour values, a green sub-stream for the extracted green colour values and a blue sub-stream for the extracted blue colour values, wherein the red, green and blue sub-streams within said time interval form one segment of the uncompressed data stream;
determining, i) in the red sub-stream of said segment, N red sets each of one or more successive equal red colour values and for each red set a run-length indicating a number of red colour values in this red set, ii) in the green sub-stream of said segment, N green sets each of one or more successive equal green colour values and for each green set a run-length indicating a number of green colour values in this green set, and iii) in the blue sub-stream of said segment, N blue sets each of one or more successive equal blue colour values and for each blue set a run-length indicating a number of blue colour values in this blue set, wherein at least one of said sets comprises at least two successive equal colour values;
generating, for said segment, a data packet composed of one red colour value from each of at least N−1 red sets, one green colour value from each of at least N−1 green sets, one blue colour value from each of at least N−1 blue sets, the run-lengths of at least N−1 red sets, the run-lengths of at least N−1 green sets, and the run-lengths of at least N−1 blue sets, which data packet forms the compressed data stream for said time interval.
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