ISO/IEC 21122-1:2019 情報技術— JPEG XS低遅延軽量画像コーディングシステム—パート1：コアコーディングシステム | ページ 6

3.1.1

band

input data to a specific wavelet filter type (3.1.49) that contributes to the generation of one of the components (3.1.13) of the image

3.1.2

band type

single number collapsing the information on the component (3.1.13) , and horizontal and vertical wavelet filter types (3.1.49) that are applied in the filter cascade reconstructing spatial image samples (3.1.42) from inversely quantized wavelet coefficients (3.1.10)

3.1.3

bit

binary choice encoded as either 0 or 1

3.1.4

bitplane

array of bits (3.1.3) having all the same significance (3.1.31)

3.1.5

bitplane count

number of significant bitplanes (3.1.4) of a code group (3.1.9) , counting from the LSB up to the most significant, non-empty bitplane

3.1.6

bitplane count subpacket

subset of a packet (3.1.34) which decodes to the bitplane counts (3.1.5) of all code groups (3.1.9) within a packet, followed by padding (3.1.35) and optional filler bytes (3.1.24)

Note 1 to entry: See subclause C.5.3.

3.1.7

byte

group of 8 bits (3.1.3)

3.1.8

codestream

compressed image data representation that includes all necessary data to allow a (full or approximate) reconstruction of the sample (3.1.42) values of a digital image

3.1.9

code group

group of quantization indices (3.1.40) in sign-magnitude representation before inverse quantization (3.1.25)

3.1.10

coefficient

input value to the inverse wavelet transformation resulting from inverse quantization (3.1.25)

3.1.11

column

set of vertically aligned precincts (3.1.36)

3.1.12

compression

process of reducing the number of bits (3.1.3) used to represent source image data

3.1.13

component

two-dimensional array of samples (3.1.42) having the same designation such as red, green or blue in the output or display device

3.1.14

continuous-tone image

image whose components (3.1.13) have more than one bit (3.1.3) per sample (3.1.42)

3.1.15

data subpacket

subset of a packet (3.1.34) which consists of the quantization index magnitudes (3.1.41) , followed by padding (3.1.35) and optional filler bytes (3.1.24)

Note 1 to entry: See subclause C.5.4.

3.1.16

deadzone quantizer

quantizer whose zero bucket has a size different from all other buckets

Note 1 to entry: Based on this, inverse deadzone quantizers can be defined as inverse quantizers whose zero bucket has a size different from all other buckets.

3.1.17

decoder

embodiment of a decoding process (3.1.18)

3.1.18

decoding process

process which takes as its input a codestream (3.1.8) and outputs a continuous-tone image (3.1.14)

3.1.19

decomposition level

set of wavelet coefficients (3.1.10) resulting from a particular level of recursive application of a wavelet transform

3.1.20

encoder

embodiment of an encoding process (3.1.23)

3.1.21

encoding process

process which outputs compressed image data in the form of a codestream (3.1.8)

3.1.22

entropy decoding

lossless (3.1.28) procedure (3.1.38) which recovers the sequence of symbols from the sequence of bits (3.1.3) produced by an entropy encoding (3.1.23) procedure

3.1.23

entropy encoding

lossless (3.1.28) procedure (3.1.38) which converts a sequence of input symbols into a sequence of bits (3.1.3) such that the average number of bits per symbol approaches the entropy of the input symbols

3.1.24

filler bytes

integer number of bytes (3.1.7) a decoder (3.1.17) will skip over on decoding without interpreting the values of the bytes itself

3.1.25

inverse quantization

inverse procedure (3.1.38) to quantization (3.1.39) by which the decoder (3.1.17) recovers a representation of the coefficients (3.1.10)

3.1.26

inverse reversible multi component transformation

inverse RCT

inverse transformation across multiple component (3.1.13) sample (3.1.42) values located at the same sample grid (3.1.43) point that is invertible without loss

Note 1 to entry: See subclauses F.3 and F.4.

3.1.27

LL band

input to a series of wavelet filters where only inverse low-pass filters are applied in horizontal and vertical direction

3.1.28

lossless

being such that, for encoding and decoding procedures (3.1.38) , the output of the decoding procedure(s) is identical to the input to the encoding procedure(s)

3.1.29

lossless coding

mode of operation which refers to any one of the coding processes defined in this document in which all of the procedures (3.1.38) are lossless (3.1.28)

3.1.30

sign subpacket

subset of a packet (3.1.34) that consists of the sign information of all non-zero quantization indices (3.1.40) within a packet, followed by padding (3.1.35) and optional filler bytes (3.1.24)

Note 1 to entry: See subclause C.5.5.

3.1.31

significance

attribute of code groups (3.1.9) that applies if, depending on the Run Mode flag in the picture header, either at least one of coefficients (3.1.10) in the code group is non-zero, or the bitplane count (3.1.5) prediction residual of the code group is non-zero

3.1.32

significance group

group of horizontally adjacent code groups (3.1.9) sharing the same significance (3.1.31) information in the significance subpacket (3.1.33)

3.1.33

significance subpacket

subset of a packet (3.1.34) that identifies which significance groups (3.1.32) within a packet are insignificant, followed by padding (3.1.35) and optional filler bytes (3.1.24)

Note 1 to entry: See subclause C.5.2.

3.1.34

packet

segment of the codestream (3.1.8) containing entropy coded information on a single precinct (3.1.36) , line and a subset of the bands (3.1.1) within this precinct and line

3.1.35

padding

bits (3.1.3) within the codestream (3.1.8) whose only purpose is to align syntax elements to byte (3.1.7) boundaries and that carry no information

3.1.36

precinct

collection of quantization indices (3.1.40) of all bands (3.1.1) contributing to a given spatial region of the image

3.1.37

precision

number of bits (3.1.3) allocated to a particular sample (3.1.42) , coefficient (3.1.10) , or other binary numerical representation

3.1.38

procedure

set of steps which accomplishes one of the tasks which comprise an encoding (3.1.23) or decoding process (3.1.18)

3.1.39

quantization

method of reducing the precision (3.1.37) of the individual coefficients (3.1.10)

3.1.40

quantization index

input to the inverse quantization (3.1.25) process which reconstructs a wavelet coefficient (3.1.10)

3.1.41

quantization index magnitude

absolute value of a quantization index (3.1.40)

3.1.42

sample

single element in the two-dimensional image array which comprises a component (3.1.13)

3.1.43

sample grid

common coordinate system for all samples (3.1.42) of an image, where the samples at the top left edge of the image have the coordinates (0,0), the first coordinate increases towards the right, the second towards the bottom

3.1.44

slice

integral number of precincts (3.1.36) whose wavelet coefficients (3.1.10) can be entropy-decoded independently

3.1.45

subpacket

substructure of a packet (3.1.34) containing information of one or multiple bands (3.1.1) of one line of a single precinct (3.1.36)

3.1.46

truncation position

number of least significant bitplanes (3.1.4) not included in the quantization index (3.1.40) of a wavelet coefficient (3.1.10)

3.1.47

uniform quantizer

quantizer whose buckets are all of equal size

Note 1 to entry: Based in this, inverse uniform quantizers can be defined as inverse quantizers whose buckets are all of equal size.

3.1.48

upsampling

procedure (3.1.38) by which the spatial resolution of a component (3.1.13) is increased

3.1.49

wavelet filter type

single number that uniquely identifies each element of the wavelet filter with regard to the number and type of horizontal and vertical decompositions

Note 1 to entry: Unlike the band type, the wavelet filter type does not include component information.