Non-linear display brightness adjustment

• US 10,264,266 B2
• Filed: 02/25/2015
• Issued: 04/16/2019
• Est. Priority Date: 02/25/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Pan, Hao
• Primary Examiner(s): Tung, Kee M
• Assistant Examiner(s): Li, Grace Q
• Application Number:
  US14/631,405
• Publication Number:
  US 20150243200A1
• Time in Patent Office: 1,511 Days
• CPC Class Codes: G06F 3/1454 involving copying of the display data of a local workstation or window to a remote workstation or window so that an actual copy of the data is displayed simultaneously on two or more displays, e.g. teledisplay
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2370/042 for monitor identification
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 5/005 Adapting incoming signals to the display format of the display terminal
• CPC Class Codes: 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
• CPC Class Codes: G09G 5/10 : Intensity circuits
• CPC Class Codes: H04N 1/6066 : dependent on the gamut of the image to be reproduced
• CPC Class Codes: H04N 1/64 : Systems for the transmission or the storage of the colour picture signal; Details therefor, e.g. coding or decoding means therefor H04N19/00 takes precedence
• CPC Class Codes: H04N 19/102 : characterised by the element, parameter or selection affected or controlled by the adaptive coding
• CPC Class Codes: H04N 19/124 : Quantisation
• CPC Class Codes: H04N 19/136 : Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/137 : Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/14 : Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/154 : Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/17 : the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 : the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 : the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/177 : the unit being a group of pictures [GOP]
• CPC Class Codes: H04N 19/182 : the unit being a pixel
• CPC Class Codes: H04N 19/184 : the unit being bits, e.g. of the compressed video stream
• CPC Class Codes: H04N 19/186 : the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/188 : the unit being a video data packet, e.g. a network abstraction layer [NAL] unit
• CPC Class Codes: H04N 19/30 : using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/33 : in the spatial domain
• CPC Class Codes: H04N 19/44 : Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/463 : by compressing encoding parameters before transmission
• CPC Class Codes: H04N 19/52 : by predictive encoding
• CPC Class Codes: H04N 19/86 : involving reduction of coding artifacts, e.g. of blockiness
• CPC Class Codes: H04N 19/98 : Adaptive-dynamic-range coding [ADRC]
• CPC Class Codes: H04N 21/42202 : environmental sensors, e.g. for detecting temperature, luminosity, pressure, earthquakes
• CPC Class Codes: H04N 21/4223 : Cameras H04N23/00 takes precedence
• CPC Class Codes: H04N 21/4318 : by altering the content in the rendering process, e.g. blanking, blurring or masking an image region image enhancement or restoration in general G06T5/00
• CPC Class Codes: H04N 21/44008 : involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/4402 : involving reformatting operations of video signals for household redistribution, storage or real-time display details of conversion of video standards at pixel level H04N7/01; video transcoding H04N19/40; adapting incoming signals to the display format of the display terminal G09G5/005; media handling at the source in data packet switching networks H04L65/764
• CPC Class Codes: H04N 21/44218 : Detecting physical presence or behaviour of the user, e.g. using sensors to detect if the user is leaving the room or changes his face expression during a TV program methods or arrangements for recognising human body or animal bodies or body parts G06V40/10; methods or arrangements for acquiring or recognising human faces, facial parts, facial sketches, facial expressions G06V40/16; methods or arrangements for recognising movements or behaviour G06V40/20; arrangements for identifying users in broadcast systems H04H60/45
• CPC Class Codes: H04N 21/4854 : for modifying image parameters, e.g. image brightness, contrast
• CPC Class Codes: H04N 23/741 : by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 5/20 : Circuitry for controlling amplitude response
• CPC Class Codes: H04N 5/505 : Invisible or silent tuning
• CPC Class Codes: H04N 9/641 : Multi-purpose receivers, e.g. for auxiliary information H04N9/642 takes precedence
• CPC Class Codes: H04N 9/67 : for matrixing camera processing pipelines for matrixing of colour signals H04N23/85

Abstract

Display brightness adjustment apparatus and methods are described in which the average brightness of a display may be scaled up or down using a non-linear function. When applying the non-linear function to scale down brightness, the contrast of the output signal may not be reduced so that the dynamic range and highlights are preserved. The non-linear brightness adjustment may be performed automatically, for example in response to ambient light level as detected by sensor(s), but may also be applied in response to a user adjustment to a brightness control knob or slider. The non-linear brightness adjustment may be performed globally, or alternatively may be performed on local regions of an image or display panel. The non-linear function may be a piecewise linear function, or some other non-linear function.

Claims

1. A system, comprising:

a display panel configured to display digital content; and

a brightness adjustment module implemented via a processor or circuitry and configured to dynamically adapt brightness of a digital content signal for the display panel in accordance with changing ambient conditions, wherein dynamically adapt comprises;

obtain information about one or more ambient conditions affecting display panel brightness from one or more sources;

determine, responsive to the one or more ambient conditions, an adjustment to a brightness level for the display panel from the obtained information;

scale the digital content signal brightness up or down to adjust the brightness level of the display panel according to the determined adjustment while preserving contrast of the digital content signal or while scaling contrast of the digital content signal by a smaller amount than brightness, wherein to scale the digital content signal brightness while preserving contrast or while scaling contrast by a smaller amount than brightness the brightness adjustment module is configured to apply a non-linear brightness adjustment function to an input digital content signal to generate an output digital content signal for the display panel, wherein the non-linear brightness adjustment function has a slope that increases as input brightness increases; and

repeat said obtain information, said determine the adjustment, and said scale the digital content signal brightness to dynamically adapt brightness of the display panel in accordance with changing ambient conditions.

2. The system as recited in claim 1, wherein, to scale the digital content signal brightness up or down according to a non-linear brightness adjustment function, the brightness adjustment module is configured to apply the non-linear brightness adjustment function to a luma component of an input digital content signal to generate an output digital content signal for display.

3. The system as recited in claim 1, wherein the obtained information includes one or more ambient lighting metrics for the display panel, and wherein, to determine the adjustment to the brightness level for the display panel from the obtained information, the brightness adjustment module is configured to determine the adjustment at least in part according to at least one of the ambient lighting metrics.

4. The system as recited in claim 3, further comprising one or more sensors configured to detect ambient lighting conditions, wherein at least one of the ambient lighting metrics for the display panel are determined according to the detected ambient lighting conditions.

5. The system as recited in claim 1, further comprising a display brightness control element configured to adjust a display brightness level setting in response to user input, wherein the obtained information includes the display brightness level setting, and wherein, to determine the adjustment to the brightness level for the display panel from the obtained information, the brightness adjustment module is configured to determine the adjustment at least in part according to the display brightness level setting.

6. The system as recited in claim 1, wherein the obtained information indicates ambient lighting conditions and a user-specified display brightness level setting, and wherein, to determine the adjustment to the brightness level for the display panel from the obtained information, the brightness adjustment module is configured to determine the adjustment according to the ambient lighting conditions and the display brightness level setting.

7. The system as recited in claim 1, wherein the non-linear brightness adjustment function is a piecewise linear function.

8. The system as recited in claim 1, wherein the display panel is divided into a plurality of regions, and wherein, to scale the display panel brightness up or down, the brightness adjustment module is configured to scale the brightness up or down separately for each region of the display panel according to a non-linear brightness adjustment function for the region.

9. The system as recited in claim 1, wherein the display panel is a high dynamic range (HDR) enabled display panel, and wherein the digital content is HDR digital content.

10. The system as recited in claim 1, wherein the brightness adjustment module is a component of a system on a chip (SOC).

11. A method, comprising:

performing, by a brightness adjustment module implemented on a device, the brightness adjustment module implemented via a processor or circuitry and configure to perform dynamically adapting brightness of a digital content signal for a display panel in accordance with changing ambient conditions, wherein dynamically adapting comprises;

obtaining information about one or more ambient conditions affecting display panel brightness of the display panel from one or more sources;

determining, responsive to the one or more ambient conditions, an adjustment to a brightness level for the display panel from the obtained information;

scaling the digital content signal brightness up or down to adjust the brightness level of the display panel according to the determined adjustment while preserving contrast of the digital content signal or while scaling contrast of the digital content signal by a smaller amount than brightness, based at least in part on applying a non-linear brightness adjustment function to an input digital content signal to generate an output digital content signal for the display panel, wherein the non-linear brightness adjustment function has a slope increases as input brightness increases; and

repeating said obtaining information, said determining the adjustment, and said scaling the digital content signal brightness to dynamically adapt brightness of the display panel in accordance with changing ambient conditions.

12. The method as recited in claim 11, wherein said scaling the digital content signal brightness comprises applying the non-linear brightness adjustment function to a luma component of the input digital content signal to generate the output digital content signal for display.

13. The method as recited in claim 11, wherein the obtained information indicates a user-specified display brightness level setting, and wherein the adjustment to brightness level for the display panel is determined at least in part from the display brightness level setting.

14. The method as recited in claim 11, wherein the display panel is divided into a plurality of regions, and wherein scaling the display panel brightness comprises scaling the brightness up or down separately for each region of the display panel according to a non-linear brightness adjustment function for the region.

15. An apparatus, comprising:

a brightness adjustment module implemented via a processor or circuitry and configured to dynamically adapt brightness of a digital content signal for a display panel in accordance with changing ambient conditions, wherein dynamically adapt comprises;

obtain information about one or more ambient conditions affecting display panel brightness of the display panel from one or more sources;

determine, responsive to the one or more ambient conditions, an adjustment to a brightness level for the display panel from the obtained information;

apply a non-linear brightness adjustment function to a luma component of an input digital content signal to generate an output digital content signal to scale display panel brightness according to the determined adjustment while preserving contrast of the digital content signal or while scaling contrast of the digital content signal by a smaller amount than brightness, wherein to scale the digital content signal brightness while preserving contrast or while scaling contrast by a smaller amount than brightness, a slope of the non-linear brightness adjustment function used to scale display panel brightness increases as input brightness increases;

repeat said obtain information, said determine the adjustment, and said apply a non-linear brightness adjustment function to the luma component to dynamically adapt brightness of the display panel in accordance with changing conditions; and

output the digital content to the display panel for display.

16. The apparatus as recited in claim 15, wherein the obtained information indicates one or more ambient lighting conditions and a current display brightness level setting for the display panel, and wherein the adjustment to brightness level for the display panel is determined at least in part from the ambient lighting conditions and the current display brightness level setting.

17. The apparatus as recited in claim 15, wherein the display panel is divided into a plurality of regions, and wherein a different piecewise linear brightness adjustment function is applied to the digital content signal corresponding to at least two of the plurality of regions.