High dynamic range tone mapping

Number: 9979895
Published: 2018-05-22
Filed: 2015-11-25
Assignee: Disney Enterprises, Inc.; ETH Zurich (Eidgenoessische Technische Hochschule Zurich)
Inventors: Smolic; Aljosa Aleksej Andrej; Aydin; Tunc Ozan; Croci; Simone Maurizio; Stefanoski; Nikolce
CPC: G06T5/50; G06T5/92; H04N1/4072; H04N23/741; H04N25/57; H04N9/77
Verdict: Low Notable software
Source: Google Patents · FreePatentsOnline

The keeper's note

HDR tone-mapping image processing.

Abstract

Embodiments herein disclose a tone mapping system that generates a base layer by filtering a frame in an HDR video. The tone mapping system then generates a tone curve using a tone mapping parameter derived from the base layer—e.g., a mean or maximum luminance value. Once the tone curve parameter is identified, the system performs temporal filtering to smooth out inconsistencies between the current value of the tone curve parameter and the values of tone curve parameter of at least one previous frame in the HDR video. The tone mapping system applies the temporally filtered tone curve to the base layer to generate a temporally coherent layer. The temporally coherent base layer can be combined with a detail layer derived from the HDR video to generate a frame of a tone mapped video.

Background

BACKGROUND(1) Field of the Invention(2) Embodiments presented in this disclosure generally relate to performing tone mapping for high dynamic range (HDR) video.(3) Description of the Related Art(4) Tone mapping is typically performed before HDR video can be outputted on a display device (e.g., a monitor, television, display on a mobile device, etc.) that does not support a high-dynamic color range. The range of colors in the HDR video may exceed the range of colors that can be outputted by the display device. As such, tone mapping converts the frames in the HDR video into corresponding frames with colors that are within the color range of the display device. Moreover, tone mapping can adjust the brightness levels as captured by cameras (which generate the HDR video) to match the capabilities of the display devices that output the video.SUMMARY(5) Embodiments herein describe a method that includes generating a base layer using a frame of a HDR video and deriving a tone curve parameter from the base layer. The method includes temporally filtering the tone curve parameter and generating a temporally coherent base layer using a tone curve derived from the temporally filtered tone curve parameter.(6) Embodiments herein describe a computer-readable storage medium comprising computer-readable program code executable in a processor to generate a base layer using a frame of a HDR video and derive a tone curve parameter from the base layer. The program code is also executable to tempor

Claims

1. A method, comprising: generating, using a computer processor, a first base layer using a frame of a high dynamic range (HDR) video; deriving a tone curve parameter from the first base layer, wherein the tone curve parameter is a statistical value derived from pixels in the first base layer; temporally filtering the tone curve parameter using a previously measured value of the tone curve parameter derived from a second base layer, wherein the second base layer is derived from a previous frame of the HDR video; and generating a temporally coherent base layer using a tone curve derived from the temporally filtered tone curve parameter. 9. A computer-readable storage medium comprising computer-readable program code embodied therewith, the computer-readable program code executable by a processor to: generate a first base layer using a frame of a high dynamic range (HDR) video; derive a tone curve parameter from the first base layer, wherein the tone curve parameter is a statistical value derived from pixels in the first base layer; temporally filter the tone curve parameter using a previously measured value of the tone curve parameter derived from a second base layer, wherein the second base layer is derived from a previous frame of the HDR video; and generate a temporally coherent base layer using a tone curve derived from the temporally filtered tone curve parameter. 15. A tone mapping system, comprising: a computer processor; and one or more memories containing a program which, when executed on the computer processor, performs an operation comprising: generating a first base layer using a frame of a high dynamic range (HDR) video; deriving a tone curve parameter from the first base layer, wherein the tone curve parameter is a statistical value derived from pixels in the first base layer; temporally filtering the tone curve parameter using a previously measured value of the tone curve parameter derived from a second base layer, wherein the second base layer is derived from a previous frame of the HDR video; and generating a temporally coherent base layer using a tone curve derived from the temporally filtered tone curve parameter.