ISO IEC 15444-10:2011 pdf – lnformation technology -JPEG 2000 image coding system: Extensions forthree-dimensional data.
K.X Packets
UpdateofRecITU.TTJtt1OISO’IF.C 15444.1 clauseK.9.
All compressed image data representing a specific tile, layer. component. resolution Icvcl and precinct appears in thc codestream in a contiguous segment called a packet. Packet data is aligned at 8-bit (one byte) boundaries,
As defined in Annex 0, resolution lesel r — 0 contains the sub-band coefiicients from the N,Ll.L hand, where N1• is the number of decomposition lcvels as defined in clause 0.3.2. Each subsequent resolution Ie%el. r ;- 0. contains the sub-hand coefficients from thc nILJHIXI(L[H XJILH XJ sub-hands, nELL excluded, as dcfincd iii Annex D. whcre n N, – r + I There are (N, I) resolution levels for a tile-component with N, decomposition levels.
The onipressed image data in a packet is ordered such that the contribution from the LLL. XLL. LXL LIX, LXX, XIX. XXI. HLL HXL. HLX. HXX. LHL, XHL. LI-tX. XHX. HHL HI-tX. LLH. XLII. LXH. XXI-t. HLH. HXH. LHH. XHH and HHH sub-hands appear in that order (i.e.. Morton scanning order). Within each sub-hand, the codebluck contributions appear in raster orskr. confined to the bounds established by the relevant precinct. Resolution level r U contains only the .V,LLL band and resolution lcvels r> 0 can only contain some of the LLIllIXJLLI1lIXJILIllIX1 bands, excluded N,LLL. Only those codeblocks that contain samples front the relevant sub-band. confined to the precinct, have any representation in the packet.
Packet data is introduced by a packet header whose syntax is described in Rec ITU-T T.800 ISOIEC 15444-I clause B. 10 and is followed by a packet body containing the actual code-bytes contributed by each of’ the relevant code- blocks. The order defined above is followed in constructing both the packet header and the packet body.
89 Packet header information coding
UpdateofReclT1J-TT.80O ISOIEC l$4M-l clause B.l0.
B.9i Tag trees
Rec. ITU-T T.800 ISOIEC 15444-I clause 8.10.2 describes two dimensional lag trees. For the purpose of a three-dimensional extcnsion, three-dimensional tag trees arc required.
A 3D tag tree is a way of representing a three-dimensional anay of non-negative mtegers in a hierarchical way. It successively creates reduced resolution levels of this three-dimensional array, forming a tree. At every node of this tree, the minimum integer of the top (up to eight) nodes below is recorded. The notation. q(m,. in,. nrI. is the value at the node that is rnth from the left, m,ih from the top and mjh from the front, at the ith level. Level 0 is the lowest level of the tag tree; it contains the top node
Sec Rec. ITIJ-T T.S00 I ISO.IEC 15444-I clause 1310.2 for Ilinher information on how to actually encode and decode values with the tag tree. The description given there is independent of the number of actual dimensions.
8.9.2 Order of iiifonnalion ithin a packet
Update of Rec. ITU-T T.800 ISOIEC 15444-I clause 13.10.8.
The following is the packet header information order for osw packet of a specific layer. tile-compuitent. resolution level and precinct.
bit for zero or non-zero length packet
(or each subband ((LIH[XJILIHIX](LIHIXJ)
for all code-blocks in this subband confined to the relevant precinct, in raster order code-block inclusion bits (it not previously included then tag tree, else one bit)
ii code-block included
if first instance of code-block
zero bit-planes information
number at coding passes included
increase of code-block length indicator (Lblock) for each codeword segment
length of codeword segment
8.10 Progression order
Update of Rcc. ITU-TT.X4X) ISO.’lI-C 15444-I clausc 11.12.
For a given tile-pail, the packets contain all compressed image data from a specific layer. a specific component, a specific resolution level, and a specific precinct. The order in which these packets are found in the codestreant is called the progression order. The ordering of the packets can progress along four axes: Layer, component. resolution level and precinct.
it is possible chat components have a ditTcrent number of resolution levels. In this ease, the resolution level that corresponds to the vLLl. sub-hand is the first resolution level (r 0) for all components. The indicca are synchronized from that point on.
8.10.1 Progression order detennination
This clause describes the algorithms that define the five possible progression orders. They are basically identical to those dcscnbcd in Rev. ITU-T T.S()( lS(yIF(’ 15444-I clause 13.12.1, but extended to three dimensions. The lines printed in bold indicate the addiliotis necessary for the third dimension
The (‘01) marker segments signal which of the jive progression orders are used scc Rev. ITU-T T.XflO ISO,’IEC’ 15444-I clause A.6.I). The progression order can also be overridden with the POC marker segment (see Rec. ITLI-t T.XOO I ISO/IEC 15444-I clause A.6.6) in any tile-part headcr. For each of the possible progression orders. the niechanism to determine the order in which packets are included is described below,
8.10.1.1 Layer-resolution Irs eI-componrnl-posltion progression
Sec Rev. ITU-TT.X00I ISOIEC 15444-I clause 13.12.1.1.
K. 10.1.2 Resolution lrsrI-In er-component-position progression
See Rev. I11J-TT.X00I ISOIF.C 15444-I clause B.12.l.2.
8.10.13 Resolution lescl-posltion-componrn(-layrr progression
Resolution levcl-position-component-laycr progression for three dimensions is defined ax the interleaving of the packets in the following order.