ITU-T Recommendations

This Amendment is the first amendment to introduce colour extension into JBIG2. There are many ideas and possibilities to incorporate colour information on JBIG2. In this amendment, as the first step of introducing coloured information, the following principles are adopted.In order to show the Text Region Segment with colour support, a flag to show colour supported Text Region Segment and a flag to show its colour space (ex. sRGB) are defined. Colour information is attached to the end of Text Region Segment as colour section, and T.45 representation is used to code colour change information to keep the decodability by the current decoder. A total of 32 colours are defined by default in this Amendment. Additional colour dictionary can be defined using T.45-like expression in Colour Palette Segment. In Generic Region Segment, if background colour is needed to define, another intermediate region segment which has the colour as foreground should be placed under the segment. The order of the priority in layout is newly defined.