# US 10,455,209 B2 · Method and apparatus for conversion of HDR signals

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- Number: US 10,455,209 B2
- Document ID: US10455209B2
- Status: Granted
- Kind: B2
- Application number: 15/196,276
- Filed: 2016-06-29
- Published: 2017-01-05
- Granted: 2019-10-22
- Earliest claimed: 2015-06-30
- Assignees: British Broadcasting Corporation
- Applicants: British Broadcasting Corporation
- Inventors: Timothy John Borer; Andrew David Raine Cotton
- Web page: https://patentgrep.com/patent/US10455209B2

## CPC

- H04N 9/77: Circuits for processing the brightness signal and the chrominance signal relative to each other, e.g. adjusting the phase of the brightness signal relative to the colour signal, correcting differential gain or differential phase (circuits for matrixing H04N9/67)
- G06T 5/92: based on global image properties
- G09G 5/02: characterised by the way in which colour is displayed {(details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607)}
- H04N 23/82: for controlling camera response irrespective of the scene brightness, e.g. gamma correction
- H04N 23/86: for controlling the colour saturation of colour signals, e.g. automatic chroma control circuits
- G06T 2207/20208: High dynamic range [HDR] image processing
- G09G 5/10: Intensity circuits
- G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
- G09G 2340/06: Colour space transformation
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- G09G 2370/04: Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- 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

Described are concepts, systems and techniques related to processing an input video signal intended for a first display to produce an output signal appropriate for a second display. The concepts, systems and techniques include converting using one or more transfer functions arranged to provide relative scene light values and remove or apply rendering intent of the input or output video signal, wherein the removing or applying rendering intent alters luminance.

## Claims

### Claim 1

A method of processing an input video signal intended for a first display to produce an output video signal appropriate for a second display, the method comprising converting the input video signal to the output video signal using one or more transfer functions arranged to:
remove rendering intent of the input video signal, wherein the rendering intent depends on a peak display light value for the first display and a surrounding luminance level for the first display, wherein removing rendering intent of the input video signal provides relative scene light values, or
provide relative scene light values and apply rendering intent of the output video signal, wherein the rendering intent depends on a peak display light value for the second display and a surrounding luminance level for the second display; wherein the removing or applying rendering intent alters luminance;
and wherein the removing or applying rendering intent is applied as a function of input RGB values according to any of:
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### Claim 2 (depends on 1)

A method according to claim 1, wherein the removing or applying rendering intent is applied to a luminance component.

### Claim 3 (depends on 1)

A method according to claim 1, wherein the removing or applying rendering intent is applied to RGB components without altering relative values such that color is unchanged.

### Claim 4 (depends on 1)

A method according to claim 1, wherein removing or applying rendering intent alters luminance such that color is unchanged.

### Claim 5 (depends on 1)

A method according to claim 1, wherein at least one of the input or output video signals is a display referred signal and the rendering intent is the rendering intent of the display referred signal.

### Claim 6 (depends on 1)

A method according to claim 1, wherein the output video signal is a display referred signal and applying rendering intent comprises an opto-optical transfer function to provide the rendering intent for the display referred signal.

### Claim 7 (depends on 1)

A method according to claim 1, wherein the input video signal is a display referred signal and removing rendering intent comprises an inverse opto-optical transfer function to remove the rendering intent from the display referred signal.

### Claim 8 (depends on 1)

A method according to claim 1, wherein one or more transfer functions are provided by a three-dimensional (3D) look up table (LUT) having values to provide the conversion.

### Claim 9

A converter for processing an input video signal intended for a first display to produce an output video signal appropriate for a second display, the converter comprising:
a processor configured and programmed with instructions to execute one or more transfer functions that:
provide relative scene referred signal values; and
remove rendering intent of the input video signal, wherein the rendering intent depends on a peak display light value for the first display and a surrounding luminance level for the first display, or apply rendering intent of the output video signal, wherein the rendering intent depends on a peak display light value for the second display and a surrounding luminance level for the second display;
wherein the removing or applying rendering intent alters luminance and is applied as a function of input RGB values according to any of:
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### Claim 10 (depends on 9)

A converter according to claim 9, wherein the removing or applying rendering intent is applied to a luminance component.

### Claim 11 (depends on 9)

A converter according to claim 9, wherein the removing or applying rendering intent is applied to RGB components without altering relative values such that color is unchanged.

### Claim 12 (depends on 9)

A converter according to claim 9, further comprising means for scaling to convert between an absolute range and a relative range.

### Claim 13 (depends on 9)

A converter according to claim 9,
wherein:
at least one of the input or output signals is a display referred signal and the rendering intent is the rendering intent of the display referred signal.

### Claim 14 (depends on 13)

A converter according to claim 13 wherein the output video signal is a display referred signal and applying rendering intent comprises an opto-optical transfer function to provide the rendering intent for the display referred signal.

### Claim 15 (depends on 13)

A converter according to claim 13 wherein the input video signal is a display referred signal and removing rendering intent comprises an inverse opto-optical transfer function to remove the rendering intent from the display referred signal.

### Claim 16 (depends on 9)

A converter according to claim 9, wherein one or more transfer functions are provided by a three-dimensional (3D) look up table (LUT) having values to provide the conversion.

### Claim 17 (depends on 9)

A device comprising the converter of claim 9.

### Claim 18 (depends on 9)

A receiver, set top box or display comprising the converter of claim 9.

### Claim 19 (depends on 9)

A system comprising the converter of claim 9.

### Claim 20 (depends on 1)

Apparatus being part of a studio chain comprising means arranged to undertake the method of claim 1.

### Claim 21 (depends on 9)

A transmitter comprising the converter of claim 9.