EP2174264A1 - Video enhancement and display power management - Google Patents
Video enhancement and display power managementInfo
- Publication number
- EP2174264A1 EP2174264A1 EP07810189A EP07810189A EP2174264A1 EP 2174264 A1 EP2174264 A1 EP 2174264A1 EP 07810189 A EP07810189 A EP 07810189A EP 07810189 A EP07810189 A EP 07810189A EP 2174264 A1 EP2174264 A1 EP 2174264A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pixel
- pattern
- transform
- display
- given
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
- G09G2320/0646—Modulation of illumination source brightness and image signal correlated to each other
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
- G09G2320/0653—Controlling or limiting the speed of brightness adjustment of the illumination source
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/066—Adjustment of display parameters for control of contrast
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0666—Adjustment of display parameters for control of colour parameters, e.g. colour temperature
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
- G09G2330/02—Details of power systems and of start or stop of display operation
- G09G2330/021—Power management, e.g. power saving
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2340/00—Aspects of display data processing
- G09G2340/16—Determination of a pixel data signal depending on the signal applied in the previous frame
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
- G09G2360/144—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light being ambient light
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/16—Calculation or use of calculated indices related to luminance levels in display data
Definitions
- the invention concerns power management and image enhancement in visual display devices and, more particularly, in liquid-crystal display devices.
- Display devices are ubiquitous in battery-powered portable electronic devices such as notebook computers and mobile, hand-held telephones where, typically, they are the largest consumers of battery power.
- LCD liquid-crystal displays
- TFT thin-film transistor
- LCD liquid-crystal displays
- An LCD screen typically includes an array of liquid-crystal pixels arranged as a plurality of rows each having a plurality of pixels, arranged in columns, with each pixel capable of displaying any one of 256 luminance values of a gray scale and the corresponding chrominance values.
- Each pixel has its own liquid crystal cell, a dedicated thin-film transistor, and a dedicated capacitor.
- the electrical field of the capacitor controls the orientation of the liquid crystals within the cell, determining the optical transmissivity of the cell and thus its luminance when lit by a backlight.
- the capacitor is charged and discharged via its transistor.
- Device activation typically is row-by-row, so that, at any one time, all column lines are connected to a single row.
- dynamic backlight control can be used, involving dynamic scaling down and up of the backlight brightness while the device is being used, e.g. in playing back a movie.
- a preferred transformation, (1), of the pixel values can be determined for minimizing perceived image distortion between the original untransformed image at maximum backlight and the transformed image under the specific backlight condition. Furthermore, a preferred transformation, (2), of the pixel values can be determined for minimizing power consumption while meeting an image-quality requirement.
- a preferred transformation can maximize the luminance of a given pattern and provide optimal contrast by assigning each pixel a value from a given dynamic range of pixel values based on the value of the probability density of the pixel luminance values for the given pattern.
- certain display attributes are taken into account for imposing constraints on transform parameters.
- Fig. 1 is a graph showing an exemplary pixel value distribution along a line of
- Fig. 2 is a graph showing the pixel value distribution of Fig. 1 approximated by a step function, and further showing how the transform slopes are computed.
- Fig. 3 is a graph showing a multi-stage transform obtained for the step function of Fig. 2.
- Fig. 4 is a representation of an exemplary procedure for transforming the given pixel values using the pixel value distribution of the given pattern in accordance with a preferred embodiment of the invention.
- Fig. 5 is a representation of a further exemplary procedure for transforming the given pixel values using the pixel value distribution of the given pattern, representing a further preferred embodiment of the invention.
- Fig. 6 is a block schematic of an exemplary embodiment of the technique.
- Fig. 1 shows given or input pixel luminance values on the x-axis, output pixel values on the y-axis, and a pictorial representation of a distribution of the pixel values.
- the straight line from (0, 0) to (255, 255) represents the identity transform which saves no power and causes no distortion.
- Fig. 1 also shows a generic multi-stage transform with 4 stages as an example. More generally, on judicious choice of the number of stages/segments and their slope, any desired transformation can be effected. Our invention includes techniques for advantageously determining the number of stages and their slopes. Constraints on Transform Shape
- a preferred transform will meet certain constraints for preventing undesirable effects. For example, if at any stage the slope of the transform were 0, then all the pixel values in that range would get compressed to a single value, resulting in total loss of contrast there. This is the case for certain transforms previously known in the art which clip the high pixel values to a threshold value, resulting in washout of bright pixels in the image. For example, washout will impair images of bulbs and lights due to loss of contrast in the region of the light. Conversely, if a slope is too large, pixel values that are close to each other are dramatically separated in the pixel-value space, causing a distorted rendition as compared with the original image.
- a swath of pixels have very similar luminance, e.g. in the court of a basketball scene. If the transform then has a high slope for these pixel values, the transformed court will have dramatically varying luminance, and the image will appear distorted.
- Fig. 2 also shows the uniform density over the entire dynamic range for comparison.
- the value of this density is denoted as U. If U(i) > U, then the number of pixels in bin i is greater than average, suggesting that we should maintain the original contrast by using an appropriate slope. If U(i) ⁇ U, then a less-than-average number of pixels is indicated in bin i, and so we can afford to lose some contrast by using a lesser slope.
- a practicable slope can be chosen as the one that transforms the uniform density with the value U(i) in bin i to another uniform density with the value U. This slope is given by On taking account of the constraints given by Equation 1, we obtain the following for determining the slope for bin /:
- Fig. 3 also shows u, the value the maximum perceived luminance.
- y f is more than the maximum value given by the current transform, t(255), so that we can scale up the transform by an appropriate factor. If y f were less than t(255), then we would scale down the transform. In either case we honor the constraints given by Equation 1.
- Fig. 4 shows an exemplary algorithm, designated as MULTISTAGE, for determining the transform t(p) , 0 ⁇ p ⁇ 256. It can be used for task (1) as described in the Summary above.
- Fig. 5 shows an exemplary algorithm, there designated as SCALING, which can be used for task (2).
- SCALING On combining procedures MULTISTAGE and SCALING, both tasks can be performed simultaneously.
- MULTISTAGE and SCALING On combining procedures MULTISTAGE and SCALING, both tasks can be performed simultaneously.
- chrominance scaling By scaling of chrominance pixels, apply a color boost to the chrominance values for improving the color combination of the processed image.
- the U and V components each are scaled up by a respective fixed factor.
- chrominance scaling can involve a generic functional transform of the luminance component.
- Fig. 6 shows different types of input 1 to a processor 2 for generating processed video frame output 3 as well as a backlight value 4 for display of video frame output 3 on an end client display device 5.
- input 1 can include any/all of: values and statistics of pixels of an input video frame, values and statistics of a past video frame in a sequence of video frames, LCD panel characteristics of the display device 5, ambient light conditions of the environment in which the input video frame was generated, and user input.
- Input data are used by processor 2 in determining transform parameters, determining a backlight value, and transforming pixel values.
- the transformed pixel values can be displayed against a backlight as determined by processor 2, or against some other supplied background.
- a video/image may be targeted for either or a combination of (i) least power consumption on the display device 5 and (ii) best possible enhancement as compared with the input.
- Techniques of the invention can be applied for static backlight setting of an individual display, or dynamically in a scenario where the backlight can be changed from frame to frame of a video sequence.
- the processor 2 in processing a frame, can make reference to at least one previously processed frame.
- a previous frame can also be used for smoothing, e.g. with a suitable small portion ⁇ of the pixel values of a previous frame added to a portion (1- ⁇ ) of the current frame of a scene.
- Techniques of the invention can generate high-quality video, still images, graphics, and screen shots of other multimedia applications such as Microsoft Power Point and Word applications, all at minimized display backlight power or at any specific display backlight power. Furthermore, the techniques can be useful for enhancing a display even where there may be little or no concern with backlight power. Our techniques can be implemented for power management and/or image enhancement in notebook-PC's, media players such as DVD playback devices, handheld consumer electronic devices, portable media players, personal digital assistant (PDA) devices, LCD TV's and mobile phones, for example.
- PDA personal digital assistant
Abstract
Description
Claims
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US2007/015436 WO2009005501A1 (en) | 2007-06-30 | 2007-06-30 | Video enhancement and display power management |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2174264A1 true EP2174264A1 (en) | 2010-04-14 |
EP2174264A4 EP2174264A4 (en) | 2010-06-16 |
Family
ID=40226363
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP07810189A Withdrawn EP2174264A4 (en) | 2007-06-30 | 2007-06-30 | Video enhancement and display power management |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP2174264A4 (en) |
KR (1) | KR20100074103A (en) |
CN (1) | CN101884048B (en) |
WO (1) | WO2009005501A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102436615B (en) * | 2011-12-05 | 2015-07-01 | 广州上源物联网科技有限公司 | Sound-light electronic tag system applied in warehouse management in power industry and method thereof |
USD766656S1 (en) | 2015-03-05 | 2016-09-20 | 8479950 Canada Inc. | Filter |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010033260A1 (en) * | 2000-03-27 | 2001-10-25 | Shigeyuki Nishitani | Liquid crystal display device for displaying video data |
US20050104842A1 (en) * | 2003-11-17 | 2005-05-19 | Lg Philips Lcd Co., Ltd. | Method and apparatus for driving liquid crystal display |
US20060139270A1 (en) * | 2004-12-29 | 2006-06-29 | Lg.Philips Lcd Co., Ltd. | Method and apparatus for driving liquid crystal dispaly device |
US20070001997A1 (en) * | 2005-06-30 | 2007-01-04 | Lg Philips Lcd Co., Ltd. | Apparatus and method of driving liquid crystal display device |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2003219505A1 (en) * | 2002-04-11 | 2003-10-27 | Moshe Ben-Chorin | Color display devices and methods with enhanced attributes |
JP3838243B2 (en) * | 2003-09-04 | 2006-10-25 | ソニー株式会社 | Image processing method, image processing apparatus, and computer program |
US7873229B2 (en) * | 2006-02-08 | 2011-01-18 | Moxair, Inc. | Distributed processing for video enhancement and display power management |
US20070185757A1 (en) * | 2006-02-09 | 2007-08-09 | Sap | Talent relationship management with E-recruiting |
-
2007
- 2007-06-30 EP EP07810189A patent/EP2174264A4/en not_active Withdrawn
- 2007-06-30 KR KR1020107002266A patent/KR20100074103A/en not_active Application Discontinuation
- 2007-06-30 CN CN200780100434.7A patent/CN101884048B/en not_active Expired - Fee Related
- 2007-06-30 WO PCT/US2007/015436 patent/WO2009005501A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010033260A1 (en) * | 2000-03-27 | 2001-10-25 | Shigeyuki Nishitani | Liquid crystal display device for displaying video data |
US20050104842A1 (en) * | 2003-11-17 | 2005-05-19 | Lg Philips Lcd Co., Ltd. | Method and apparatus for driving liquid crystal display |
US20060139270A1 (en) * | 2004-12-29 | 2006-06-29 | Lg.Philips Lcd Co., Ltd. | Method and apparatus for driving liquid crystal dispaly device |
US20070001997A1 (en) * | 2005-06-30 | 2007-01-04 | Lg Philips Lcd Co., Ltd. | Apparatus and method of driving liquid crystal display device |
Non-Patent Citations (1)
Title |
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See also references of WO2009005501A1 * |
Also Published As
Publication number | Publication date |
---|---|
KR20100074103A (en) | 2010-07-01 |
EP2174264A4 (en) | 2010-06-16 |
CN101884048B (en) | 2013-05-01 |
CN101884048A (en) | 2010-11-10 |
WO2009005501A1 (en) | 2009-01-08 |
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A4 | Supplementary search report drawn up and despatched |
Effective date: 20100520 |
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RIC1 | Information provided on ipc code assigned before grant |
Ipc: G09G 3/20 20060101ALI20100512BHEP Ipc: G09G 3/36 20060101ALI20100512BHEP Ipc: G06K 9/40 20060101AFI20090128BHEP |
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