CN100591108C - Image signal processing method, image signal processing apparatus, and image displaying apparatus - Google Patents
Image signal processing method, image signal processing apparatus, and image displaying apparatus Download PDFInfo
- Publication number
- CN100591108C CN100591108C CN200580000066A CN200580000066A CN100591108C CN 100591108 C CN100591108 C CN 100591108C CN 200580000066 A CN200580000066 A CN 200580000066A CN 200580000066 A CN200580000066 A CN 200580000066A CN 100591108 C CN100591108 C CN 100591108C
- Authority
- CN
- China
- Prior art keywords
- mentioned
- look
- display unit
- picture signal
- characteristic
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Controls And Circuits For Display Device (AREA)
- Picture Signal Circuits (AREA)
Abstract
An image signal processing method for nonlinear correcting image signals to be inputted to a display device (103), wherein the nonlinear correction characteristic is modified based on a brightness ofthe place where the display device (103) is located. According to this method, even when the display brightness of the display device (103) uniformly rises due to the ambient light, the characteristicof the brightness perceived by human being for image signals can be made linear.
Description
Technical field
The present invention relates to picture signal is carried out the image display device of image-signal processing method, image signal processing apparatus and this image signal processing apparatus of use of non-linear correction.
Background technology
Human vision property is non-linear, and especially, as shown in Figure 5, the bright degree that the people perceives presents the characteristic of logarithmic function with respect to brightness.In addition, as shown in Figure 6A, the display brightness of the picture signal of CRT (cathode ray tube) had so-called gamma (γ) characteristic.Therefore, in the display unit of using CRT, the visual characteristic of gamma characteristic and logarithmic function is cancelled out each other, and the bright degree that the people perceives presents linear characteristic basically with respect to picture signal.
In contrast, the DMD that appears on the market in recent years (Digital Mirror Device, Digital Micromirror Device) or PDP (Plasma Display Panel, Plasmia indicating panel) etc. display unit does not have gamma characteristic, shown in Fig. 6 B, these display unit have linear characteristic with respect to the display brightness of picture signal.Therefore, in these display unit, the bright degree that the people perceives presents the characteristic of logarithmic function with respect to picture signal.Therefore, for the bright degree that the people is perceived picture signal reverts to linear characteristic, must carry out non-linear correction to picture signal.As this method, the method (for example, opening flat 10-153983 communique referring to the spy) that the use look-up table shown in Fig. 7 (below, note by abridging be " LUT ") carries out non-linear correction has for example been proposed.
Fig. 8 is the diagram of an example that the input-output characteristic of such LUT is shown.Here, " input gray level " is the picture signal before revising, represent signal level (signal level) with 256 grades of " 0 "～" 255 " to the received image signal of LUT input, " display gray scale " is revised picture signal, the signal level from the output image signal of LUT output standardized for the mode of " 255 " with its maximum.Only expressed among Fig. 8 input gray level for " 0 ", " 10 ", " 20 ",, display gray scale when " 250 ".
When display unit is arranged on dim place and does not have ambient light, display unit for the gamma characteristic that does not have PDP etc., when input gray level was carried out non-linear correction shown in Figure 8, the relation of input gray level and display brightness presented the such gamma characteristic shown in the characteristic curve A of Fig. 9 A.Therefore, people's bright degree that input gray level is perceived is the characteristic of the such substantial linear shown in the characteristic curve B of Fig. 9 B.
But, in bright place, shown in the characteristic curve C of Fig. 9 A like that owing to be subjected to the influence of ambient light, display brightness is consistent to rise, even carry out non-linear correction in the past, the bright degree that the people is perceived reverts to the characteristic of linearity.The characteristic curve D of Fig. 9 B represents that the people at this moment the bright degree that input gray level perceived, in the low part of input gray level, can not clearly discern the variation of gray scale.
This is relevant with human vision property, can consider as follows.In dim place, suppose display gray scale direct representation display brightness shown in Figure 8, then at input gray level when 10 gray scales are increased to 20 gray scales, display brightness is increased to " 0.9 " from " 0.2 ", the lightness that the people perceives becomes original 4.5 times.Yet, in bright place, because the influence of ambient light, when supposing the brightness that display brightness only rises for example suitable with " 30 ", even then input gray level is increased to 20 gray scales from 10 gray scales, display brightness also only is increased to " 30.9 " from " 30.2 " respectively, the people almost perception less than the variation of lightness.Certainly, under the situation of bright image, for example the ratio with respect to 240 gray scales and the display brightness of 250 gray scales under dim place is 244.1/223.2=1.09, this does not have big difference with the ratio 274.1/253.2=1.08 of identical display gray scale under bright place, can not consider the influence of ambient light.
Like this, method according in the past non-linear correction, because display unit is subjected to the influence of the ambient light in set place, the bright degree that the people is perceived reverts to linear characteristic, particularly can not be identified in the variation of gray scale in low, the dark image of input gray level, thereby have the problem of tonal distortion.
Summary of the invention
The present invention proposes in order to address the above problem, even the display unit that picture signal has linear characteristic is subjected to the influence of ambient light and the display brightness of display unit is as one man risen, also can make the characteristic of the lightness that the people perceives picture signal become the image display device of linear image-signal processing method, image signal processing apparatus and this image signal processing apparatus of use even purpose aims to provide display brightness.
The present invention is the image-signal processing method that the picture signal that is input to display unit is carried out non-linear correction, it is characterized in that: according to the lightness in the set place of display unit, change the characteristic of non-linear correction.
Description of drawings
Fig. 1 is the circuit block diagram of the image display device of the embodiment of the invention 1;
Fig. 2 A is the diagram that the relation of input gray level and display brightness in the picture signal modification method of the embodiment of the invention 1 is shown;
Fig. 2 B is the diagram that the relation of the bright degree that input gray level and people perceive is shown;
Fig. 3 is the circuit block diagram of other image display devices of the embodiment of the invention 1;
Fig. 4 is the circuit block diagram of the image display device of the embodiment of the invention 2;
Fig. 5 is the diagram that the bright degree that the people perceives brightness is shown;
Fig. 6 A is the diagram that the relation of the picture signal of CRT and display brightness is shown;
Fig. 6 B is the diagram that the relation of the picture signal of DMD, PDP and display brightness is shown;
Fig. 7 is the circuit block diagram of the image display device of prior art;
Fig. 8 is the diagram of an example that the input-output characteristic of look-up table is shown;
Fig. 9 A is the diagram that the relation of input gray level and display brightness in the picture signal modification method of prior art is shown;
Fig. 9 B is the diagram that the relation of the bright degree that input gray level and people perceive is shown.
Embodiment
Below, with reference to the description of drawings embodiments of the invention.
Fig. 1 is the circuit block diagram of the image display device 100 of the embodiment of the invention 1.101 pairs of received image signals of image signal processing apparatus are that input gray level carries out non-linear correction, and output to display unit 103.Display unit 103 is to use the display unit that does not have gamma characteristic of DMD or PDP etc.Image signal processing apparatus 101 has the ambient light test section 104 of the lightness around detecting and the transformation component 105 that input gray level is carried out non-linear correction according to lightness on every side.
Ambient light test section 104 has the optical sensor 106 of the lightness around detecting and will be converted to the AD converter section 107 of digital signal from the detection signal of optical sensor 106.Transformation component 105 has a plurality of LUT 108 that are used for input gray level is carried out non-linear correction
1～108
4With according to the detection signal of ambient light test section 104 from a plurality of LUT 108
1～108
4The middle LUT selection portion 112 of selecting 1 LUT.Fig. 1 shows 4 LUT 108
1～108
4, still, the number of LUT is not limited to 4, and it can be made of quantity arbitrarily as required.Usually,, can adapt to the light surround of wider scope, in addition, can make the change in display brightness that is accompanied by the LUT switching set smallerly by increasing the number of LUT.
A plurality of LUT 108
1～108
4According to (display gray scale)=K * (input gray level) γ, input gray level is carried out non-linear correction respectively.Wherein, gamma factor γ is the value greater than 1, and it is set to different values respectively for each LUT.In addition, COEFFICIENT K is the coefficient that is used to make the maximum of display gray scale to equate with the maximum of input gray level, can be expressed as
K=(maximum of input gray level)
(1-γ)
In the present embodiment, LUT 108
1Be the LUT of non-linear correction usefulness that does not have the dim place of ambient light etc., its gamma factor γ is set at 2.2.In dim place, using LUT 108
1Thereby input gray level is carried out non-linear correction carry out image when showing, the relation of input gray level and display brightness is shown in the characteristic curve A of Fig. 2 A.And the bright degree that the people perceives presents linear characteristic basically with respect to input gray level shown in the characteristic curve B of Fig. 2 B.In addition, shown in the characteristic curve C of Fig. 2 A, when display brightness as one man being risen, if the LUT 108 that uses dim place to use in the influence that is subjected to ambient light
1Carry out non-linear correction, then shown in the characteristic curve D of Fig. 2 B, the bright degree that the people perceives has been destroyed linear characteristic, in the low part of input gray level, tonal distortion.Therefore, at this moment, shown in the characteristic curve E of Fig. 2 A, switch to the little LUT of gamma factor γ 108
4Carry out non-linear correction.So the bright degree that the people perceives just shown in the characteristic curve F of Fig. 2 B, can revert to linear characteristic with respect to input gray level basically.
In the present embodiment, though with 4 LUT 108
1～108
4Gamma factor γ be set at 2.2,2.1,2.0,1.9 respectively, switch these LUT according to the testing result of ambient light test section 104, but the present invention also can use other structures, as long as it is just passable to change the characteristic of the non-linear correction that input gray level is carried out according to ambient light.For example, can use arithmetic processing apparatus such as digital signal processor to realize the function of a plurality of look-up tables and look-up table selection portion, as shown in Figure 3, as transformation component 205, can use arithmetic processing apparatus 200, as the detection signal of received image signal and ambient light, the structure of output display gray scale.According to this structure, can use less circuit block to constitute transformation component.
In addition, in the present embodiment, though be the characteristic that changes non-linear correction by the value that changes gamma factor γ,, also can utilize additive method to change the characteristic of non-linear correction.For example,, can become linear such correction characteristic to the picture signal before revising, obtain the characteristic of non-linear correction by the lightness that the actual measurement people perceives for various ambient lights.Like this, no matter be the display unit that the display brightness of picture signal is had which type of characteristic, can obtain the lightness that the people is perceived is the correction of linearity with respect to the picture signal before revising characteristic.
Embodiment 2
Fig. 4 is the circuit block diagram of the image display device 300 of the embodiment of the invention 2.Be marked with identical label for the circuit block identical, and omit its explanation with embodiment 1.Embodiment 2 is with the difference of embodiment 1, not only changes the characteristic of non-linear correction according to ambient light, and change according to the display mode of display unit 103.For example, in using the display unit of PDP, on its drive principle, can the gray-scale displayed number there be the relation of trade off (trade-off) between (below, note by abridging be " gray scale display capabilities ") and the high-high brightness that can show.Therefore, the display mode as display unit 103 is provided with " dynamic mode ", " mode standard ", " film mode " etc., and is designed to the user and can selects the display mode oneself liked.Here, " dynamic mode " is to sacrifice the gray scale display capabilities slightly and the display mode that improves high-high brightness, and " film mode " is to suppress high-high brightness and the display mode that improves the gray scale display capabilities, and " mode standard " is the display mode in the middle of the two.
As mentioned above, the bright degree that the people perceives is subjected to the influence of ambient light, certainly, also directly has influence on the brightness that display unit shows.And,, must be not only to but also to change the characteristic of non-linear correction according to ambient light according to the high-high brightness that display unit shows for the bright degree that the people is perceived becomes linearity with respect to input gray level.
And,,, switch to the little LUT of gamma factor γ along with ambient light strengthens for same display mode.In addition, under the situation that light is identical, in " dynamic mode ", switch to the big LUT of gamma factor γ around, in " film mode ", switch to the little LUT of gamma factor γ.
Like this, by not only changing the characteristic that non-shape is revised according to ambient light but also according to the display mode of display unit, even the user is switched display mode and changed the high-high brightness that display unit shows, the bright degree that the people is perceived reverts to linear characteristic basically with respect to input gray level.
In embodiment 2, as the signal of representing the high-high brightness that display unit shows, though used from the display mode signal of display unit 103 outputs, but, it also can be other signal, so long as the signal of the high-high brightness that the expression display unit shows just can, for example, can use the APL that revises preceding picture signal.In addition, as the signal of the high-high brightness of representing display unit, also can use the signal of expression display mode and these 2 kinds of signals of APL of picture signal.
In addition, in embodiment 2, as transformation component 305, though show the structure of switching a plurality of LUT,, also can use other structure, so long as it is just passable to change the structure of characteristic of non-linear correction.For example,, can use arithmetic processing apparatus such as digital signal processor, thereby can adopt the signal of the detection signal of received image signal and ambient light and expression high-high brightness and export the structure of display gray scale as transformation component 305.
In addition, in embodiment 2, method as the characteristic that changes non-linear correction, though switch the different a plurality of LUT of gamma factor γ, but, for the high-high brightness of various ambient lights and display unit, also can become the characteristic that linear such correction characteristic is obtained non-linear correction with respect to input gray level by the bright degree that the actual measurement people perceives.
According to the present invention, even the influence that is subjected to ambient light can be provided the display brightness of display unit is as one man risen, also can make the characteristic of the lightness that the people perceives picture signal become the image display device of linear image-signal processing method, image signal processing apparatus and this image signal processing apparatus of use.
Image-signal processing method of the present invention, image signal processing apparatus and image display device, even be subjected to the influence of ambient light the display brightness of display unit is as one man risen, also can make the characteristic of the lightness that the people perceives picture signal become linearity, so, be useful as the image display device that picture signal is carried out non-linear correction.
Claims (11)
1. an image-signal processing method is the image-signal processing method that the picture signal that is input to display unit is carried out non-linear correction, it is characterized in that:
Preserve the different respectively a plurality of look-up tables of characteristic of non-linear correction;
At least basis is selected 1 look-up table to the testing result of the lightness in the set place of above-mentioned display unit from above-mentioned a plurality of look-up tables;
Wherein, be recorded in the display brightness in above-mentioned a plurality of look-up table, have the value that improves the gray scale display capabilities at least;
Above-mentioned display unit has linear characteristic for the display brightness of picture signal;
The characteristic of above-mentioned non-linear correction according to above-mentioned lightness, changes the characteristic of above-mentioned non-linear correction to the input gray level of received image signal.
2. image-signal processing method according to claim 1, it is characterized in that: above-mentioned non-linear correction will with the proportional picture signal of γ power of picture signal before revising as revised picture signal, above-mentioned lightness is bright more, the value of above-mentioned γ is set at more little value, and wherein γ is greater than 1.
3. image-signal processing method according to claim 1 is characterized in that: the lightness that perceives with the people becomes the characteristic that linear mode is set above-mentioned non-linear correction with respect to the picture signal before revising.
4. an image-signal processing method is the image-signal processing method that the picture signal that is input to display unit is carried out non-linear correction, it is characterized in that:
Preserve the different respectively a plurality of look-up tables of characteristic of non-linear correction;
At least basis is selected 1 look-up table to the testing result and the shown high-high brightness of above-mentioned display unit of the lightness in the set place of above-mentioned display unit from above-mentioned a plurality of look-up tables;
Wherein, be recorded in the display brightness in above-mentioned a plurality of look-up table, have value that improves the gray scale display capabilities and the value that improves high-high brightness at least;
Above-mentioned display unit has linear characteristic for the display brightness of picture signal;
The characteristic of above-mentioned non-linear correction according to the high-high brightness of above-mentioned lightness and the demonstration of above-mentioned display unit, changes the characteristic of above-mentioned non-linear correction to the input gray level of received image signal.
5. image-signal processing method according to claim 4, it is characterized in that: above-mentioned non-linear correction will with the proportional picture signal of γ power of picture signal before revising as revised picture signal, above-mentioned lightness is bright more, the value of above-mentioned γ is set at more little value, and the high-high brightness that above-mentioned display unit can show is high more, the value of above-mentioned γ is set at big more value, and wherein γ is greater than 1.
6. an image signal processing apparatus is the image signal processing apparatus that the picture signal that is input to display unit is carried out non-linear correction, it is characterized in that having:
The ambient light test section detects the lightness in the set place of above-mentioned display unit;
Transformation component is imported the testing result of above-mentioned ambient light test section, thereby and the picture signal before revising is carried out non-linear correction be transformed to revised picture signal;
Wherein, above-mentioned transformation component has the respectively different a plurality of look-up tables of the characteristic of non-linear correction and select the look-up table selection portion of 1 look-up table according to the testing result of above-mentioned ambient light test section from above-mentioned a plurality of check table;
Be recorded in the display brightness in above-mentioned a plurality of look-up table, have value that improves the gray scale display capabilities and the value that improves high-high brightness at least;
Above-mentioned display unit has linear characteristic for the display brightness of picture signal;
Above-mentioned transformation component carries out above-mentioned non-linear correction to the input gray level of received image signal.
7. image signal processing apparatus according to claim 6 is characterized in that: use arithmetic processing apparatus to realize the function of above-mentioned a plurality of look-up table and above-mentioned look-up table selection portion.
8. an image display device has the described image signal processing apparatus of claim 6.
9. an image signal processing apparatus is the image signal processing apparatus that the picture signal that is input to display unit is carried out non-linear correction, it is characterized in that having:
The ambient light test section detects the lightness in the set place of above-mentioned display unit;
Transformation component is imported the signal of the testing result and the high-high brightness that the above-mentioned display unit of expression shows of above-mentioned ambient light test section, thereby and the picture signal before revising is carried out non-linear correction be transformed to revised picture signal;
Wherein, above-mentioned transformation component has the respectively different a plurality of look-up tables of the characteristic of non-linear correction and select the look-up table selection portion of 1 look-up table according to the high-high brightness that the testing result and the above-mentioned display unit of above-mentioned ambient light test section shows from above-mentioned a plurality of look-up table;
Be recorded in the display brightness in above-mentioned a plurality of look-up table, have value that improves the gray scale display capabilities and the value that improves high-high brightness at least;
Above-mentioned display unit has linear characteristic for the display brightness of picture signal;
The input gray level of the above-mentioned transformation component pair received image signal that is associated with above-mentioned picture signal carries out above-mentioned non-linear correction.
10. image signal processing apparatus according to claim 9 is characterized in that: use arithmetic processing apparatus to realize the function of above-mentioned a plurality of look-up table and above-mentioned look-up table selection portion.
11. an image display device has the described image signal processing apparatus of claim 9.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004061997 | 2004-03-05 | ||
| JP061997/2004 | 2004-03-05 | ||
| JP065197/2004 | 2004-03-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1774918A CN1774918A (en) | 2006-05-17 |
| CN100591108C true CN100591108C (en) | 2010-02-17 |
Family
ID=36760997
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200580000066A Expired - Fee Related CN100591108C (en) | 2004-03-05 | 2005-03-02 | Image signal processing method, image signal processing apparatus, and image displaying apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100591108C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120154355A1 (en) * | 2009-11-27 | 2012-06-21 | Canon Kabushiki Kaisha | Image display apparatus |
| JP2014130170A (en) * | 2012-12-27 | 2014-07-10 | Ricoh Co Ltd | Image projection apparatus and control method |
-
2005
- 2005-03-02 CN CN200580000066A patent/CN100591108C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1774918A (en) | 2006-05-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7439984B2 (en) | Image signal processing method, image signal processing apparatus, and image displaying apparatus | |
| CN102667899A (en) | Image display apparatus | |
| US20080117162A1 (en) | Liquid crystal display and driving method thereof | |
| WO2010146885A1 (en) | Image display apparatus and method for controlling same | |
| CN107665689B (en) | Gamma chip, time sequence control chip and liquid crystal display device | |
| JP2003186455A (en) | Liquid crystal display device and its driving method | |
| GB2400765A (en) | Luminance-dependent video display control | |
| US20090096819A1 (en) | Driving circuit apparatus | |
| KR100442004B1 (en) | Gray level conversion method and display device | |
| JP2002366122A (en) | Liquid crystal display device and its driving method | |
| KR100875326B1 (en) | Liquid crystal display response characteristics determination method and presentation method | |
| US20170221405A1 (en) | Picture conversion method, picture conversion device, computer program for picture conversion, and picture display system technical field | |
| KR20030072534A (en) | Linear average picture level detecting apparatus and automatic normalizing gain embodying method | |
| CN101083720A (en) | TV receiver and TV receiving method | |
| CN100591108C (en) | Image signal processing method, image signal processing apparatus, and image displaying apparatus | |
| US6801179B2 (en) | Liquid crystal display device having inversion flicker compensation | |
| JPH0918806A (en) | Method for displaying image and its device | |
| WO2020235109A1 (en) | Image display device, image display system, image display method, and computer program | |
| JP4899321B2 (en) | Image signal processing method, image signal processing apparatus, and image display apparatus | |
| JP3394885B2 (en) | Liquid crystal display | |
| JP3839024B2 (en) | Color correction method | |
| JP2019184629A (en) | Display device, display device control method, and program | |
| US20030052868A1 (en) | Image display unit | |
| KR20030082406A (en) | Measuring psnr of full color video | |
| US20040008215A1 (en) | Color re-mapping for color sequential displays |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100217 Termination date: 20140302 |