Perceptual luminance nonlinearity-based image data exchange across different display capabilities

Patent metadata

Field	Value
Publication number	US-10242650-B2
Application number	US-201815960303-A
Country	US
Kind code	B2
Filing date	Apr 23, 2018
Priority date	Dec 6, 2011
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A handheld imaging device has a data receiver that is configured to receive reference encoded image data. The data includes reference code values, which are encoded by an external coding system. The reference code values represent reference gray levels, which are being selected using a reference grayscale display function that is based on perceptual non-linearity of human vision adapted at different light levels to spatial frequencies. The imaging device also has a data converter that is configured to access a code mapping between the reference code values and device-specific code values of the imaging device. The device-specific code values are configured to produce gray levels that are specific to the imaging device. Based on the code mapping, the data converter is configured to transcode the reference encoded image data into device-specific image data, which is encoded with the device-specific code values.

First claim

It is claimed:

1. A method performed on one or more processors comprising:
receiving metadata, the metadata includes a first luminance value associated with an image file;
determining a normalized perceptual curve signal value V from the first luminance value;
determining a normalized color component value C based on a functional model of

C
=

(

max
⁡

[

(

V

1
/
m

-

c
1

)

,
0

]

c
2

-

c
3

⁢

V

1
/
m

)

1
/
n

;

determining an absolute value L from at least the normalized component value C,
wherein parameters n, m, c 1 , c 2 , and c 3 are predetermined values; and
rendering an image from the image file based on the determining of the absolute value L.

2. The method of claim 1 , wherein:

n
=

2610
4096

×

1
4

≃
0.1593017578125

;

m
=

2523
4096

×
128

≃
78.84375

;

c
1

=

c
3

-

c
2

+
1

=

3424
4096

≃
0.8359375

;

c
2

=

2413
4096

×
32

≃
18.8515625

;
and

c
3

=

2392
4096

×
32

≃

18.6875
.

3. The method of claim 1 , wherein the first luminance value is 10 bits.

4. The method of claim 1 , wherein the first luminance value is 12 bits.

5. The method of claim 1 , wherein the first luminance value is received from a non-transitory storage media.

6. The method of claim 1 , wherein the normalized color component value C is a red (R), green (G), or blue (B) component.

7. A method performed on one or more processors comprising:
receiving metadata, the metadata includes a first luminance value associated with an image file;
determining a normalized perceptual curve signal value V from the first luminance value;
determining a normalized luminance value Y based on a functional model of

Y
=

(

max
⁡

[

(

V

1
/
m

-

c
1

)

,
0

]

c
2

-

c
3

⁢

V

Assignees

• Dolby Laboratories Licensing Corp

Inventors

• Miller Jon Scott
• Daly Scott
• Nezamabadi Mahdi
• Atkins Robin

Classifications

• G09G5/06

  using colour palettes, e.g. look-up tables · CPC title

• G09G2340/0435

  Change or adaptation of the frame rate of the video stream · CPC title

• G09G2320/0276

  for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction · CPC title

• G09G5/005

  Adapting incoming signals to the display format of the display terminal · CPC title

• G09G2340/06

  Colour space transformation · CPC title