# US 2018/0027262 A1 · Methods, systems and apparatus for electro-optical and opto-electrical conversion of images and video

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- Number: US 2018/0027262 A1
- Document ID: US20180027262A1
- Status: Published application
- Kind: A1
- Application number: 15/545,782
- Filed: 2016-01-26
- Published: 2018-01-25
- Earliest claimed: 2015-01-27
- Assignees: Thomson Licensing
- Applicants: Thomson Licensing
- Inventors: Erik REINHARD; Pierre ANDRIVON; Philippe BORDES; Christophe CHEVANCE; Jurgen STAUDER; Patrick MORVAN; Edouard FRANCOIS; Joaquin ZEPEDA SALVATIERRA
- Web page: https://patentgrep.com/patent/US20180027262A1

## CPC

- H04N 19/98: Adaptive-dynamic-range coding [ADRC]
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/85: using pre-processing or post-processing specially adapted for video compression
- G09G 2320/0271: Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
- G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
- G09G 2370/04: Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
- G09G 2370/12: Use of DVI or HDMI protocol in interfaces along the display data pipeline
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

The present principles are directed to a parameterized OETF/EOTF for processing images and video. The present principles provide a method for encoding a picture, comprising: applying a parameterized transfer function to a luminance (L) signal of the picture to determine a resulting V(L) transformed signal; encoding the resulting V(L); wherein the parameterized transfer function is adjusted based on a plurality of parameters to model one of a plurality of transfer functions. The present principles also provide for a method for decoding a digital picture, the method comprising: receiving the digital picture; applying a parameterized transfer function to the digital picture to determine a luminance (L) signal of the digital picture, the parameterized transfer function being based on a plurality of parameters; wherein the parameterized transfer function is adjusted based on a plurality of parameters to model one of a plurality of transfer functions.

## Claims

### Claim 1

A method for encoding a picture, the method comprising:
receiving a picture;
applying a parameterized transfer function (102, 204, 603) to a luminance (L) of pixels of the picture to determine a resulting transformed luminance V(L);
encoding the resulting transformed luminance V(L);
wherein the parameterized transfer function is based on:
V

(
L
)
=
sL
n
+
c
L
n
+
st
+
m
and is adjusted based on five parameters s, n, c, t and m to model this transfer function, wherein s, n, c and t are different from zero.

### Claim 2 (depends on 1)

The method of claim 1, wherein the parameterized transfer function is based on:
V

(
L
)
=
s

(
L
-
b
a
)
n
+
c
(
L
-
b
a
)
n
+
st
+
m
and is adjusted based on two other parameters a and b.

### Claim 3

A method for encoding a picture, the method comprising:
receiving a picture;
applying a parameterized transfer function to a luminance (L) of pixels of the picture to determine a resulting transformed luminance V(L);
encoding the resulting transformed luminance V(L), wherein the parameterized transfer function is based on:
V

(
L
)
=
k

sL
n
+
c
L
n
+
st
+
m
and is adjusted based on six parameters c, m, k, s, n, t to model this transfer function.

### Claim 4 (depends on 1)

The method of claim 1, wherein the parameterized transfer function is based on:
V

(
L
)
=
k

s

(
L
-
b
a
)
n
+
c
(
L
-
b
a
)
n
+
st
+
m
and is adjusted based on two other parameters a and b.

### Claim at position 5

5-6. (canceled)

### Claim 7 (depends on 1)

The method of claim 1, wherein a parameter among said parameters allows the parameterized transfer function to determine a desired value of V(L) based on at least one selected from a group of: a smallest value of the luminance L and a highest value of the luminance L.

### Claim 8 (depends on 1)

The method of claim 1, further comprising tone mapping the luminance (L).

### Claim 9 (depends on 1)

The method of claim 1, wherein the parameterized function has a non-linear end-to-end behavior.

### Claim 10

(canceled)

### Claim 11 (depends on 1)

The method of claim 1, further comprising encoding the parameters and signaling the encoded parameters in a bit-stream.

### Claim 12

(canceled)

### Claim 13 (depends on 11)

The method of claim 11, wherein the signaling is performed using at least one syntax element included in at least one of a Picture Parameter Set (PPS), a Sequence Parameter Set (SPS), a Supplemental Enhancement Information (SEI) message, a Video Usability Information (VUI), Consumer Electronics Association (CEA) message, and a header.

### Claim 14 (depends on 1)

The method of claim 1, wherein the luminance is at least one selected from a group of: RGB, Y, a linear combination of linear RGB, a luma that is a linear combination of non-linear RGB, and non-linear luminance.

### Claim 15 (depends on 1)

The method of claim 1, further comprising determining at least one color channel, wherein the luminance is determined for the at least one color channel.

### Claim 16

(canceled)

### Claim 17

An apparatus for encoding at least a picture, the apparatus comprising:
an encoder (600, 800) configured to apply a parameterized transfer function to a luminance (L) of pixels of the picture to determine a resulting transformed luminance V(L) and to encode the resulting transformed luminance V(L);
wherein the parameterized transfer function is based on:
V

(
L
)
=
sL
n
+
c
L
n
+
st
+
m
and is adjusted based on five parameters s, n, c, t and m to model said transfer function, wherein s, n, c, t are different from zero.

### Claim 18

A method for decoding an encoded picture, the method comprising:
receiving the encoded picture;
decoding the encoded picture to determine a decoded picture;
applying a parameterized transfer function to the decoded picture to determine a luminance (L), the parameterized transfer function being based on:
L

(
V
)
=
(
c
-
(
V
-
m
)

st
V
-
m
-
s
)
1
/
n
and is adjusted based on five parameters s, n, c, t and m to model this transfer function, wherein s, n, c and t are all different from zero.

### Claim 19 (depends on 18)

The method of claim 18, wherein the parameterized transfer function is based on:
L

(
V
)
=
a

(
c
-
(
V
-
m
)

st
V
-
m
-
s
)
1
/
n
+
b
and is adjusted based on two other parameters a and b.

### Claim 20

A method for decoding an encoded picture, the method comprising:
receiving the encoded picture;
decoding the encoded picture to determine a decoded picture;
applying a parameterized transfer function to the decoded picture to determine a luminance (L), wherein the parameterized transfer function is based on:
L

(
V
)
=
(
c
-
(
V
-
m
k
)

st
V
-
m
k
-
s
)
1
n
wherein c, m, k, s, n, t are parameters and V is a codeword, wherein s, n, c and t are all different from zero.

### Claim 21 (depends on 18)

The method of claim 18, wherein the parameterized transfer function is based on:
L

(
V
)
=
a

(
c
-
(
V
-
m
k
)

st
V
-
m
k
-
s
)
1
n
+
b
and is adjusted based on two other parameters a and b.

### Claim 22

A method for decoding an encoded picture, the method comprising:
receiving the encoded picture;
decoding the encoded picture to determine a decoded picture;
applying a parameterized transfer function to the decoded picture to determine a luminance (L), wherein the parameterized transfer function is based on:
L

(
V
)
≈
(
-
Vu
V
-
V
max

(
1
+
u
)
)
1
/
n
wherein Vmax, u and n are parameters.

### Claim 23 (depends on 22)

The method of claim 22, wherein an optimization algorithm is utilized to determine the parameters u and n.

### Claim 24 (depends on 23)

The method of claim 23, wherein the values of the parameters u and n are determined based on a reference curve that is based on luminance/codeword pairs (Li, Vi).

### Claim 25 (depends on 24)

The method of claim 24, wherein the values of the parameters u and n are determined by adding non-uniform weights to the luminance/codeword pairs (Li, Vi).

### Claim 26

A method for decoding an encoded picture, the method comprising
receiving the encoded picture;
decoding the encoded picture to determine a decoded picture;
applying a parameterized transfer function to the decoded picture to determine a luminance (L), wherein the parameterized transfer function is based on
L

(
V
)
=
(
c
-
(
V
-
m
)

st
min

(
V
-
m
-
s
,
M
)
)
1
/
n
wherein c, m, s, t and n are parameters, where c, m, s, t are all different from zero, and where M is a constant.

### Claim 27

(canceled)

### Claim 28

A method for decoding an encoded picture, the method comprising:
receiving the encoded picture;
decoding the encoded picture to determine a decoded picture; applying a parameterized transfer function to the decoded picture to determine a luminance (L), wherein the parameterized transfer function is based on:
L

(
V
)
=
(
c
-
(
V
)

st
V
-
s
)
1
/
n
and wherein c, s, t and n are parameters.

### Claim 29

(canceled)

### Claim 30 (depends on 18)

The method of claim 18, wherein a parameter of the plurality of parameters allows the parameterized transfer function to determine a desired value of the luminance L based on at least one selected from a group of: a smallest value of a codeword V and a highest value of the codeword V.

### Claim 31 (depends on 18)

The method of claim 18, wherein the parameterized function has a non-linear end-to-end behavior.

### Claim 32 (depends on 18)

The method of claim 18, wherein the parameterized function performs inverse tone mapping.

### Claim 33 (depends on 18)

The method of claim 18, further comprising receiving information representative of the parameterized transfer function.

### Claim 34 (depends on 26)

The method of claim 26, wherein the received information is included in at least one of a Picture Parameter Set (PPS), a Sequence Parameter Set (SPS), a Supplemental Enhancement Information (SEI) message, a Video Usability Information (VUI), Consumer Electronics Association (CEA) message, and a header.

### Claim 35 (depends on 18)

The method of claim 18 wherein the luminance is at least one selected from a group of: RGB, Y, a linear combination of linear RGB, a luma that is a linear combination of non-linear RGB, and non-linear luminance.

### Claim 36 (depends on 18)

The method of claim 18, further comprising determining at least a color channel, wherein the luminance is determined for the at least a color channel.

### Claim 37

An apparatus for decoding at least an encoded picture, the apparatus comprising:
a decoder configured to decode the encoded picture to determine a decoded picture and to apply a parameterized transfer function to the decoded picture to determine a luminance (L), the parameterized transfer function being based on:
L

(
V
)
=
(
c
-
(
V
-
m
)

st
V
-
m
-
s
)
1
/
n
and adjusted based on five parameters s, n, c, t and m to model this transfer functions, wherein s, n, c and t are all different from zero.