CN101523480B - Color mapping method - Google Patents
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- CN101523480B CN101523480B CN200780038213.1A CN200780038213A CN101523480B CN 101523480 B CN101523480 B CN 101523480B CN 200780038213 A CN200780038213 A CN 200780038213A CN 101523480 B CN101523480 B CN 101523480B
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- H04N9/3111—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources
- H04N9/3114—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources by using a sequential colour filter producing one colour at a time
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Abstract
A color mapping method maps an input image signal (IS) into an output image signal (OS) for a display (DD) with display pixels (Pi) having sub-pixels (RP, GP, BP, YP) with primary colors (RW, GW, BW, YW) defining a display color gamut (WG). A look-up table (1) comprises stored luminances (LU) of reflective spectra (RS) at different chromaticities (Lambada O) within the display color gamut (WG). The reflective spectra (RS) are spectra of reflective objects (RO) having a substantial maximum reflectivity at the corresponding chromaticities (Lambada O). The color mapping method comprises a gamut mapping (2), retrieving (3) a looked-up luminance (Yl), a factor determination (4), and adapting the mapped luminance (Ym; Y). The gamut mapping (2) maps the input image signal (IS) having input pixel colors defined by an input luminance (Y) and an input chromaticity (x, y) into a mapped image signal (MS) having corresponding mapped pixel colors defined by a mapped luminance (Ym; Y) and a mapped chromaticity (xm, ym). The input pixel colors lie within an input color gamut different than the display color gamut (WG). The looked-up luminance (Yl) is retrieved (3) by looking up the stored luminance (LU) in the look-up table (1) at the mapped chromaticity (xm, ym). The factor (F) is determined (4) from a difference between the looked-up luminance (Yl) and the mapped luminance (Ym; Y). The mapped luminance (Ym; Y) is adapted (5) by using the factor (F; G) to obtain an output luminance (Ys) nearer to the looked-up luminance (Yl) than the mapped luminance (Ym). The image output signal (OS) is defined by the mapped chromaticity (xm, ym) and the output luminance (Ys).
Description
Technical field
The present invention relates to the method for design display, method, display and the computer program of manufacturing display.
Background technology
For color display, conventional display has three primary colors: red, green and blue.In Europe, these trichromatic chromaticity coordinates are by the EBU standard that is used for the single-definition content and be used for the Rec709 standard definition of high-definition content.Chromaticity coordinate also is called as color dot or color.In other countries, different standards may define described trichromatic color.In the EBU standard, the chromaticity coordinate of red primaries in CIE 1931 xy color spaces is: x=0.64 and y=0.33, green primary color is: x=0.29 and y=0.60, blue primary is: x=0.15 and y=0.06.Also defined the white point of display in the EBU standard, this white point is the D65 (6500K) of x=0.3127 and y=0.3290 close to chromaticity coordinate.In fact, display manufacturer may be selected the white point that is different from D65.Many display device have more partially blue any white point, for example 8600K or even 10000K.The color of this group primary colors and white point has been determined the color representation of display.When using the EBU primary colors, the brightness ratio by the red, green and blue primary colors obtains white D65 at 22: 71: 7.
This conventional display with above-mentioned three kinds of EBU primary colors can't reproduce all visible colors.The color that only is positioned within the color triangle take described primary colors as the summit just can be revealed, and perhaps more precisely, the color that only is positioned at the 3-D display territory just can be revealed.Perhaps in other words, the colour gamut of EBU display is defined as in chrominance space the zone in the described triangle that comprises its border.Therefore, especially very saturated color, for example monochromatic, can't reproduce out.Monochromatic (monochromatic color) refers to have unimodal color in visible spectrum on specific wavelength.
Recently, so-called wide color gamut displays is just receiving increasing concern.These displays have selected primary colors with the acquisition colour gamut larger than the colour gamut of the primary colors of EBU standard.Therefore, wide color gamut displays can produce the color more saturated than EBU display.In wide colour gamut LCD display, the three primary colors that are used for wide colour gamut can obtain by the transmission band of regulating spectrum backlight and/or change color filter.Alternately, or additionally, can within described triangle or outside, but preferably, add another primary colors within the visible range of color.Wide colour gamut with three kinds of primary colors is called as when showing and strengthens colour gamut and show, the wide colour gamut that has more than three kinds of primary colors shows that being called as many primary colors shows.
Most of contents be encoded in the colour gamut by EBU primary colors definition (that is, television camera records scene according to this colour gamut, and most of natural color is not very saturated).Concerning wide color gamut displays, display color gamut may differ greatly with the input colour gamut.Be used directly to drive wide color gamut displays if be generally the received image signal of rgb signal, color rendering will distortion so, and concerning most of images, does not wish that this color rendering is higher than the color rendering of general EBU colour gamut.If before driving wide colour gamut primary colors, thereby color map is applied to received image signal, the EBU gamut extension is arrived wide colour gamut, can realize better color rendering.Yet what the color map of the known saturated growth of common use realized on wide color gamut displays is the color rendering of non-the best.
Similarly, if the EBU content must show having on the display that provides less than the primary colors of the colour gamut of EBU colour gamut, if perhaps wide colour gamut content must show on the display with EBU colour gamut, color map must narrow down to less display color gamut with the input colour gamut so, and color rendering is suffered damage.
Summary of the invention
The object of the invention is to improve the color rendering of display, the colour gamut that the primary colors of described display covers is different from the colour gamut of input signal.
A first aspect of the present invention provides a kind of Color Mapping Approach as claimed in claim 1.A second aspect of the present invention provides a kind of color map circuit as claimed in claim 13.A third aspect of the present invention provides a kind of display as claimed in claim 14.A fourth aspect of the present invention provides a kind of computer program as claimed in claim 18.Defined in the dependent claims favourable embodiment.
Color Mapping Approach according to a first aspect of the invention is mapped to output image signal for display with received image signal, described display comprises the display pixel with sub-pixel, described sub-pixel has the primary colors that has defined display color gamut, and described display color gamut has covered all can be by the color of this display demonstration.Suppose thereby the quantity of sub-pixel is also selected the quantity of primary colors and the color of primary colors, to obtain the display color gamut greater than the input colour gamut of input signal.A kind of typical puppet on this wide color gamut displays resembles and looks fluorescence seemingly for: some saturated colors.Or in other words, some saturated colors look than the observer based on picture material expect brighter.For the display of display color gamut less than the input colour gamut, typical puppet resembles and is, some saturated colors have too low brightness and look and seem dark, i.e. brightness makes mistakes again uncontrollably.Alternately, can differently select trichromatic color.
In real world, people can see object, and this is because object reflexes to red, green and blue cone on the human eye retina with light from light source.CIE 1931 xy chromaticity coordinates can be by the color of using the color-match function calculating to go out to mate catoptrical spectrum.These xy chromaticity coordinates have provided the expression of the color that (standard) observer it will be appreciated that.If the object in scene 100% reflects the incident light, and light source has smooth (or relatively flat) spectrum, sees the object of white.This object has the highest brightness at all in by the reflecting object of this light illumination.Another reflection for example will have very saturated redness at the object of the very narrow band at 630nm place, and therefore absorbs all light outside the arrowband that is positioned at about 630nm.Therefore, when by the illumination of identical wide spectrum light source, the brightness of this red object is necessarily far below the brightness of this white object.
For the maximum of the reflectance spectrum of the object of estimating to have different colours (for example, abiogenous typical the highest, or possible the highest on mathematics) brightness, the brightness of the reflectance spectrum of definite (real world) object in different colourities place in display color gamut, wherein, described object has with the corresponding color of specific colourity (such as the such redness of Coca-Cola, because it can be by theoretical or actual color filter, such as coating, generate).Reflectance spectrum is to have the spectrum of the reflecting object of maximum reflectivity basically at different colourities places.Or rather, the reflectance spectrum of such real-world objects is the spectrum of the light that reflected by this real-world objects.The brightness of this spectrum is display in the object brightness of the brightness that generates with the corresponding colourity of the color of real-world objects place.For example, the high-high brightness of the reflectance spectrum of a large group band bandpass filter can be used with different width and centre frequency.For each color filter, for light source or the spectrum of sunlight that for example has smooth spectrum calculates xy chromaticity coordinate and relative brightness.Therefore, in other words, can determine that this kind color is with respect to the relative brightness of white brightness for every kind of color or the chromaticity coordinate that is positioned at display color gamut.Be not required for every kind of color storage relative brightness.And can be one group of color storage relative brightness, and the brightness of actual color can interpolation obtain (when use characteristic nature color, when for example using the brightest leaf green, being interesting) from stored group.Must be noted that this type of brightness in the reflectance spectrum at different colourities places determines known in publication " Maximum Visual Efficiency of ColoredMaterials ", by David L.MacAdam, in J.O.S.A, volume 25, nineteen thirty-five, the 361st to 367 page.
Resemble for fear of fict fluorescence or dim puppet occurring, and compare according to the display of past principle, described display must be proofreaied and correct more accurately.
The brightness of the reflectance spectrum at different colourities places in display color gamut that described Color Mapping Approach has used that preamble discusses.The brightness of these expectations for example is stored in look-up table, or uses function, and the 2-d polynomial that for example approaches the housing (hull) (color mountain (color mountain)) of maximum reflection/glow color is modeled.Described 2-d polynomial can be parabola.Alternately, can use two-dimensional Gaussian function.Must be noted that and to use the theoretical expectation brightness of determining, replace the expectation brightness of measuring such as the Shrodinger curve.Even also can use combination (for example mean value) mensuration and expectation brightness theory.
Described Color Mapping Approach comprises Color Gamut Mapping, and the received image signal that this Color Gamut Mapping will have by the input pixel color of input brightness and the definition of input colourity is mapped to the map image signal that has by the corresponding mapping pixel color of mapping brightness and the definition of mapping colourity.Described input pixel color is positioned at the input colour gamut different from display color gamut.The brightness of expectation can be by searching the expectation brightness value at mapping colourity place in look-up table, or obtain by calculating with respect to degradation mode under the relative value of white brightness or brightness.Color become bright annoyingly before, certain tolerance deviation can be arranged, particularly point on the direction of black, even larger deviation may be arranged.
Determine a factor according to the difference between expectation brightness and mapping brightness.Adjust described mapping brightness (described mapping brightness for example obtains from primary chromaticities conversion or Color Gamut Mapping of the prior art) to obtain the output brightness than the more approaching expectation brightness of mapping brightness by using this factor.The output signal of image is by mapping colourity and output brightness definition.Certainly, the technician knows, two step processes of above conceptive description can be realized by single mapping transformation in practice.
Must be noted that the present invention does not carry out emulation to display, but use the expectation brightness by the light of one group of real-world objects reflection, wherein, each of described object has the color corresponding to specific colourity in display color gamut.If necessary, the brightness that obtains after mapping is corrected to close to expectation brightness.Therefore, the demonstration image that generates looks can be more natural, and this is because every kind of color shows with the brightness corresponding to the brightness of the real-world objects with respective color.
In one embodiment, expectation brightness is stored in look-up table, and in another embodiment, generates expectation brightness with mathematical model.The expectation brightness of these generations can be stored for using in the future.
In one embodiment, by the light source that use is scheduled to, the wide spectrum light source of for example containing at least visible-range throws light on real-world objects to obtain the spectrum by the light of this real-world objects reflection, and described spectrum is for example equal-energy spectrum or spectrum of sunlight.
In one embodiment, each expectation brightness (LU, Y1) be basically the maximum total amount of the light that is reflected, preferably, this expectation brightness (LU, Y1) can multiply each other to determine with the theoretical spectral that is used for each colourity by light source that will be selected, this theoretical spectral is such as being to have the spectrum of 100% or 0% projection for each wavelength.
In one embodiment, mapping brightness is limited (clip) to the brightness that is essentially storage.Therefore, the driving signal that is used for the display primary colors by change makes brightness basically be complementary to prevent bright color with the brightness of the real reflecting object with same color.
Can use further correction in more complicated embodiment, other brightness or the factor stored of current by looking for (for example adjacent color) colourity for example, or observe the actual brightness of adjacent color in image that obtains, thereby keep/emphasize local image structure (descending by using less further brightness), but this has exceeded central principle of the present invention.
In one embodiment, described Color Mapping Approach obtains the other brightness of searching by the brightness at the input colourity place of input signal of searching storage in look-up table.Mapping brightness is scaled by factor, this factor basically with searching brightness and equating at the ratio of searching brightness of inputting the colourity place at mapping colourity place.The advantage of this convergent-divergent is to have prevented from resembling because of the puppet that cutting causes.
In one embodiment, described Color Gamut Mapping only is applied to Color Gamut Mapping input colourity.Therefore, brightness is inputted in mapping brightness exactly.This Color Gamut Mapping only will from the chromaticity transformation of input colour gamut in different display color gamut, and not affect brightness.
In one embodiment, described Color Gamut Mapping provides color enhancement, and this color enhancement for example, is in the reinforcement that has more than the species saturation in the wide color gamut displays of three kinds of primary colors.
In one embodiment, the display of having used described Color Mapping Approach is optimized to improve color rendering.Color map of the present invention can be within display and is defined the color representation of display, or is applied in independent device, and display only obtains calibrated input signal.Described Color Mapping Approach can combine with such display, with the brightness of further reduction Show Color and have any mismatch between the brightness of real world reflecting object of same color.The display of optimizing like this can be according to following method for designing design.The pixel color of the pixel that described display has obtains by mixing four kinds of primary colors at least.These primary colors have defined the display color gamut of this display.Therefore, this display color gamut has covered the color that all can be shown by this display.Yet these primary colors must satisfy that specific condition avoids fluorescence occurring in color rendering or dim puppet resembles.
The fluorescence puppet resembles or dim puppet resembles for fear of occurring, and can select described at least four kinds of colors, so that the brightness of the pixel color that generates is more near nature/maximum color (before using further algorithm correction).
By embodiment by reference to the following description, these and other aspects of the present invention will obviously also will be elucidated.
Description of drawings
In the drawings:
What Fig. 1 showed reflectance spectrum in " shape of a hoof " visible color space of xy colorimetric plane waits brightness track schematic diagram,
Fig. 2 shows the light source of illuminated objects,
Fig. 3 shows the block diagram of an embodiment of color map circuit,
Fig. 4 shows the block diagram of another embodiment of color map circuit,
Fig. 5 shows the block diagram of the another embodiment of color map circuit,
Fig. 6 shows the schematic diagram with LCD and display device backlight,
Fig. 7 shows the schematic diagram of the display device with DMD and colour wheel,
Fig. 8 shows the high-level flow of display design method, and this display has the primary colors of optimizing selection for color rendering,
Fig. 9 shows the process flow diagram of an embodiment of display design method,
Figure 10 shows the process flow diagram of an embodiment of display design method,
Figure 11 shows the process flow diagram according to an embodiment of display design method,
Figure 12 shows another process flow diagram of display design method, and
Figure 13 shows has the example of the colour gamut of the brightness of coupling basically.
Should be noted in the discussion above that the project that has same reference numerals in different accompanying drawings has identical architectural feature and identical function, or identical signal.Make explanation when function and/or the structure to such project, needn't do repetition of explanation to it again in detailed description.
Embodiment
Fig. 1 shows the schematic diagram that waits the brightness track of the reflectance spectrum in " shape of a hoof " visible color space of xy-colorimetric plane.Transverse axis represents the x chromaticity coordinate of CIE 1931, and vertical pivot represents the y chromaticity coordinate of CIE 1931." shape of a hoof " track VA represents the border of visible color.The color that has the xy chromaticity coordinate on track VA is 100% saturated color, and it also is called as monochrome, because the spectrum of these colors only comprises single wavelength.The wavelength of numeral take nm as unit along track VA.Adopt the primary colors of EBU: red RE, green GE and blue BE, all colors that have the xy chromaticity coordinate within take primary colors RE, GE, BE as the triangle EG on summit can be shown.The xy chromaticity coordinate of white is positioned on curve WH.For example, expressed white D65 on this curve.
As according to the display that uses EBU primary colors RE, GE, BE and known, if the components R i of input signal, Gi and Bi (seeing Fig. 6) all have its maximal value, need the certain ratio between these primary colors, with the expectation white point that obtains to show.Usually, the maximal value of the components R i of these input signals, Gi, Bi equates, and is level when being used for simulating signal, and for example 0.7V, be digital when being used for digital signal, for example for 255 of 8 position digital signals.Below, each signal has and is originating in 0 and end at normalized value in 1 scope.Therefore, if the components R i of input signal, Gi and Bi are 1, should have a ratio to make the white point of expectation to be revealed between primary colors RE, GE, BE (and proofreaies and correct display according to conventional principle, with white point and the colour cast of demonstration expectation, but this has also revised the performance of other colors).For example, suppose that the white point of expectation is D65 (x=0.3127, y=0.3290), and the chromaticity coordinate of primary colors is: red RE:x=0.64, y=0.33, green GE:x=0.29, y=0.60, blue BE:x=0.15, y=0.06.Now, can calculate the ratio that should have between the redness, green of display and blue brightness 22: 71: 7.Yet, used more partially blue white point in many displays, for example the brightness ratio between red, green, blue is 20: 70: 10.
Fig. 1 also shows the example by the wide color gamut displays of primary colors RW, GW, BW definition.Defined by the triangle WG take primary colors RW, GW, BW as the summit color that wide color gamut displays thus shows.
Referring to Fig. 2, the example that waits the brightness track that how can define reflectance spectrum in the xy chrominance space is described.In desirable the setting, voluminous object RO is provided the light source L2 illumination of wide spectrum LI2.In this example, described spectrum is the spectrum (spectrum of sunlight with corresponding colour temperature of 6500K) of standard sources D65.In the realization of an exemplary optimal colors natural brightness, different object RO has 100% reflectivity basically to some wavelength, or is 0 to the reflectivity of other wavelength.Therefore, concerning (approach) was monochromatic, corresponding object RO had the reflectivity of 100% (or higher) basically in the certain wave strong point, and was essentially 0 (or lower) at the reflectivity at other wavelength places.At the other end of scale, the brightest white object has 100% reflectivity basically in whole visible ranges of wavelength.For Neutral colour, object may have high reflectance in the wavelength region may of less.Can be for example by the center the logical reflective filter of the band on specific wavelength, or respectively by the logical reflective filter of the band of two or more centers on two or more different center frequency, represent so indirect look.Must be noted that object can have different spectrum, but have identical colourity xy.Some in those objects are understood than the more light of some other reflection, thereby can have higher brightness.Fig. 1 shows the high-high brightness that reflecting object with specific colourity xy may have.The example of above maximum reflectivity is only the straightforward procedure that obtains in the practice of object spectra of maximum reflection, also can be such as obtain such spectrum (such as the typical case who seeks the brightest red object, the brightest normally leaf green etc.) based on the real spectrum from nature.After these data have been arranged, just can be for all colourities obtain one group of high-high brightness, this group high-high brightness can be stored in storer (look-up table) or can further be mathematically modeling (such as approaching with polynomial expression or index etc. this shell (hull) etc.).
For each object RO measures catoptrical brightness LU.From these are measured, can construct track such as brightness such as grade shown in Figure 1.Represent these tracks such as brightness such as grade by the numeral that relative brightness is shown.The brightness of in an example shown, reflecting the white object of all light be set to 100 represent 100%.The brightness that shows all its reflectance spectrums with 90 tracks that represent is coloured object of 90% of white object brightness.The brightness of this reflectance spectrum at different colourities places is determined known in publication " Maximum Visual Efficiency of Colored Material ", by David L.MacAdam, in J.O.S.A, volume 25,1935, the 361 pages to 367 pages.Must be noted that if select another kind of white with another spectrum LI2, the high-high brightness that is used for so identical reflecting object can be different, thereby the brightness track that waits shown in Figure 1 may difference.
Get back to now Fig. 1, these tracks such as brightness such as grade are used to the color that will show on display relative brightness BR and the brightness LU of the reflectance spectrum of the object RO with same color compare.Can be clear that from Fig. 1, the brightness that has respectively with the reflecting object RO of primary colors RE, GE, BE same color is respectively 22,77 and 8.Must be noted that the brightness ratio between them is defined as red: green concerning the EBU primary colors RE that generates white D65, GE, BE: blue=22: 71: 7.Therefore, if the total brightness of white D65 is normalized to 100, the normalization high-high brightness of redness, green and blue component is respectively 22,71 and 7 so.Below, described normalization high-high brightness also is called as high-high brightness, luminance factor, if or can know the normalization high-high brightness that refers to from the context, what for to can only be referred to as brightness.In documents and materials, described luminance factor also is called as lightness (lightness).
This just means that when the Ri of input signal component was 1, the brightness of red primaries was 22.The brightness that has the object RO of same color with red primaries RE is also 22.When the Gi of input signal component was 1, the brightness of green primary color was 71.On the other hand, the brightness that has an object RO of same color with green primary color is 77.When the Bi of input signal component was 1, the brightness of blue primary was 7.On the other hand, the brightness LU that has an object of same color with blue primary is 8.Therefore, concerning the selection of described primary colors, the brightness of primary colors is complementary with corresponding brightness LU basically.In order to obtain between display color gamut and reflection colour colour gamut coupling preferably, must check that display brightness also is complementary with corresponding brightness LU at other colors places.For example, input signal Ri and Gi are that the brightness of the yellow that produced in 1 o'clock is 93=22+71, and are 97 at the reflecting brightness at this color place.
Can prove in an identical manner, the wide color gamut displays with three primary colors RW, GW, BW has unmatched brightness, particularly for green and red.For white D65, the brightness ratio of red primaries, green primary color and blue primary is 26: 68: 7.The brightness that has respectively with the reflecting object RO of primary colors RW, GW, BW same color is respectively 12,31,7.Therefore, if only there is red primaries RW to produce light, for redness, there is the approximately mismatch of twice between the brightness LU of the brightness of primary colors RW and GW and corresponding coloured object RO, if and only have green primary color GW to produce light, for green, also have the approximately mismatch of twice.Than the brightness of the reflection colour with identical saturation degree, the brightness of red primaries and green primary color is too high.This has caused can producing to these colors the impression of not expecting, namely when using with for the identical driving signal of the driving signal with trichromatic common color gamut display the time, shown object is fluorescence.
What realized is, can reduce by increasing another primary colors at least the impact of one or more primary colors.This will be illustrated by two examples.If first example shows the effect of adding white primary colors W, and second example shows the effect of adding xanthan look YW.Alternately, can only select three kinds of primary colors, selected color makes with shown in Figure 1 and selects wide colour gamut primary colors RW, GW, BW to compare less mismatch situation only can occur.
In using EBU primary colors R, G, the B RGBW display as RGB (red, green and blue) and the white primary colors of white D65 conduct, white D65 is respectively 11,35,4,50 by associating brightness ratio between red primaries, green primary color, blue primary and white primary colors and obtains.These brightness values 11,35,4 should be respectively compare with the brightness 22,77,8 that has with the object RO of EBU primary colors R, G, B same color.As seen, when selection like this is used for the primary colors of RGB, produced high mismatch between the brightness LU of the reflectance spectrum of the brightness value of primary colors R, G, B and respective objects RO.In this embodiment, brightness is too low, thereby causes too dark and therefore heavy shade produced dim impression.
Using EBU primary colors RW, GW, BW as RGB (red, green and blue) and white D65 in the RGBW display as the white primary colors W that adds, white D65 is respectively 11,35,4,50 acquisitions by associating brightness ratio between red primaries, green primary color, blue primary and white primary colors.These brightness values 11,35,4 should be respectively compare with the brightness 12,31,7 that has with the object RO of EBU primary colors RW, GW, BW same color.As seen, when selection like this is used for the primary colors of RGB, provide the matching effect of very big improvement between the brightness LU of the reflectance spectrum of the brightness value of primary colors RW, GW, BW and respective objects RO.Yet concerning its effective secondary colour yellow, its brightness is 11+35=46, and can find in Fig. 1 for primary colors RW and GW, and the brightness LU with reflecting object RO of identical yellow is about 91.For the secondary colour magenta, luminance factor is that 11+4=15 and brightness are 19.For the secondary colour cyan, luminance factor is that 35+4=39 and brightness are 50.Therefore, for yellow, still there is larger mismatch.
Must be noted that secondary colour is two kinds of colors between primary colors, so they are by only using two kinds of primary colors to realize.
Present another example of explanation wherein, provides and has used EBU primary colors R, G, B as RGB and added the RGBY display of xanthan look YW.Be used for obtaining primary colors R, the G of white D65, the ratio of B, YW is 11: 35: 7 now: 47.These brightness values 11,35,7 should be respectively compare with the brightness 22,7,8 that has with the object RO of primary colors R, G, B same color.As seen, when selection like this is used for the primary colors of RGB, produced higher mismatch between the brightness LU of the reflectance spectrum of the brightness value of primary colors R and G and respective objects RO.Equally in this embodiment, brightness is too low, and causes the too dark impression of heavy shade.
If described RGBY display be based on wide primary colors RW, GW, BW's and increased the xanthan look, situation just is greatly improved.In order to obtain between display color gamut and reflection colour colour gamut matching effect preferably at the primary colors place, the brightness ratio of red primaries, green primary color, blue primary and xanthan look is respectively 13,34,7,47.These brightness values 13,34,7 should be respectively compare with the brightness 12,31,7 that has with the object RO of primary colors RW, GW, BW same color.As seen, when selection like this is used for the primary colors of RGB, produced the effect of basically mating between the brightness LU of the brightness value of primary colors RW, GW, BW and the reflectance spectrum of respective objects RO.Equally, concerning it all effectively the secondary colour yellow, its brightness is 13+34+47=94, and can find in Fig. 1 for primary colors RW, GW, YW, and the brightness LU with reflecting object RO of identical yellow is approximately 91.Therefore, now, obtained the effect of basically mating between the corresponding bright of the brightness of yellow and yellow reflecting object.Concerning the secondary colour magenta, its brightness value is that 13+7=20 and its luminance factor are 19.For the secondary colour cyan, its brightness value is that 34+7=41 and its luminance factor are 50.Therefore, existence is for the basic coupling of all primary colors and secondary colour.Thereby, all colours in wide colour gamut, all obtained basic coupling.
As seen from above example, according to the selection of primary colors, larger mismatch may occur.This mismatch can be reduced by the mode of the driving of display primary colors being carried out light modulation.Even found to provide the primary colors of coupling basically, may still have less deviation.The light modulation that drives by handle combines with the primary colors that these mate preferably, can further improve the color rendering of display.The embodiment that the driving of display primary colors is carried out light modulation is illustrated with reference to Fig. 3 to Fig. 5.
Fig. 2 shows the light source that object is thrown light on.Broad spectrum light source L2 generation has the light LI2 of wide spectrum with illumination reflecting object RO.For specific wavelength or one group of wavelength, object RO has high reflectivity.Reflected light has spectrum RS, and this spectrum RS is corresponding to colourity λ 0 and brightness LU.This spectrum also is called as reflectance spectrum.Owing to Fig. 2 being described in the description to Fig. 1, repeat no more herein.
Fig. 3 shows the block diagram of an embodiment of color map circuit.Received image signal IS has defined input picture, and described input picture is comprised of the input pixel with input pixel color.Although herein will be about at CIE 1931 x, the present invention will be described for the received image signal that defines in the y color space, but the present invention should not only limit to this x, and the y color space has defined therein and maybe can determine the color space of brightness and colourity but also can be applicable to other.The example in such space has CIE 1976 u ' v ' color spaces and vedio color space Y CrCb.Even also the present invention can be applied in the RGB color space, but this will be more complex, because colourity and brightness must be calculated according to the RGB component.If received image signal is encoded in the RGB color space, and do not wish also to be useful on the extra computation of determining colourity and brightness, received image signal must be transformed into linear light domain from gamma (gamma) RGB territory, such as the xyY space.
The input pixel color is by input brightness Y and input colourity x, y definition.The input pixel color is limited in the input gamut range.Color Gamut Mapping device 2 will shine upon or transformation applications makes map image signal MS have to received image signal IS to be different from the mapping colour gamut of inputting colour gamut.Map image signal MS has colourity xm and ym.If the input colour gamut is expanded, the difference of shining upon between colour gamut and input colour gamut may cause too high former colour brightness, if perhaps the mapping colour gamut is less than the input colour gamut, the difference between them may cause too low former colour brightness.
Usually, Color Gamut Mapping device 2 is processed the map image signal MS of received image signal IS to have obtained to strengthen with respect to received image signal IS.For example, Color Gamut Mapping device 2 can be any can be to brightness Y and colourity x, the influential colour switching of y (for example, three dimensional matrix arithmetic), can be perhaps only at chromaticity coordinate x, the colour switching of the upper operation of y (for example, the brightness preservation saturation degree is extended Color Gamut Mapping (luminance retraining saturation stretching gamutmapping)).In upper a kind of situation about mentioning, mapping brightness Ym equates with input brightness Y.Or in other words, input brightness Y is not processed by Color Gamut Mapping device 2.
The present invention can be used in display that having of any type be different from the display color gamut of inputting colour gamut.For example, for the EBU coded signal, this display can be wide colour gamut (greater than the EBU colour gamut) LCD.Alternately, this display can have the colour gamut less than EBU colour gamut, and for example the LCD on mobile device, perhaps following when must showing on the display device with the less colour gamut that is defined by the EBU primary colors at the input signal of encoding on wide primary colors.Panchromatic demonstration has three kinds or more primary colors possibly.
Factor determines that circuit 4 receives mapping brightness Ym and searches brightness Y1 to determine expression mapping brightness Ym and to search the factor F1 of difference between brightness Y1.Brightness regulating circuit 5 reception mapping brightness Ym and factor F1 are to provide output brightness Ys.Brightness regulating circuit 5 is by using factor F to regulate mapping brightness Ym to obtain than mapping brightness Ym closer to the output brightness Ys that searches brightness Y1.For example, brightness regulating circuit 5 is gain multiplier or the scaler that multiply each other shining upon brightness Ym and factor F1.Can selectivity factor F1 make output brightness Ys be restricted to and search brightness Y1.Alternately, factor F1 can be the mapping brightness Ym ratio shared with a part of searching brightness Y1 ratio.If brightness Ys there is no and departs from brightness Y1 concerning mapping colourity xm, ym, the color rendering in output image signal OS is optimum.Therefore, Color Gamut Mapping device 2 can strengthen received image signal IS, for example stretches (color stretching) by using color, and can not cause some colors in output image signal OS to become too bright or too dark.Must be noted that if mapper 2 does not act on input brightness Y or do not change input brightness Y, shining upon brightness Ym can be input brightness Y.Above hardware or software block are described and have only been described simple a realization, and the technician will understand brightness regulating circuit and how merge its evaluation unit that is used for the computational mathematics model to obtain to be used for the expectation brightness of input mapping colourity.
Fig. 4 shows the block diagram of another embodiment of color map circuit.This color map circuit is based on circuit shown in Figure 3, and only difference is that Color Gamut Mapping device 2 does not affect input brightness Y, therefore shines upon brightness Ym identical with input brightness Y.Only have colourity x, y is mapped.To the operation of this circuit with identical with reference to the described circuit of Fig. 3.
Fig. 5 shows the block diagram of another embodiment of color map circuit.This color map circuit is based on circuit shown in Figure 4.Difference is, has increased and has searched circuit 6, and factor is determined the now definite ratio of circuit 4, and brightness regulating circuit 5 is gain multiplier.Search circuit 6 and receive input colourity x, y also searches corresponding brightness LU in LUT1.Corresponding to input colourity x, the brightness of searching of y is called as Y2.This brightness Y2 has and input colourity x, the high-high brightness LU of the reflecting object RO of the corresponding color of y.Factor is determined the definite input colourity of circuit 4 x, y and corresponding mapping colourity xm, and the brightness Y2 of ym and the ratio of Y1 are with acquisition factor G=Y2/Y1.Gain multiplier will input brightness Y and factor G multiplies each other, to obtain output brightness Ys.
The display that color map may be optimized with reproducing for natural colour combines.Such display is described with reference to Fig. 8 to 11.Color map can be used for the device with reference to the illustrated LCD of Fig. 6 (liquid crystal display), or is used for installing with reference to the described DMD of Fig. 7 (digital micromirror is as display).
Fig. 6 shows liquid crystal indicator.In an illustrated embodiment, pixel Pi comprises four liquid crystal sub-pixel RP, GP, BP, YP.Color filter RF, GF, BF, YF are associated with sub-pixel RP, GP, BP, YP.Color filter RF, GF, BF, YF may reside in the opposite side of sub-pixel RP, GP, BP, YP, therefore between light source LR, LG, LB, LY and sub-pixel RP, GP, BP, YP.Not every sub-pixel RP, GP, BP, YP must have color filter.In an illustrated embodiment, have four light source LR, LG, LB, LY that driven by driver LDR, described four light sources define primary colors RW, GW, BW, the YW of display device DD together with color filter RF, GF, BF, YF.In Fig. 7, the color and the wave filter RF, the GF that are associated, BF, YF coupling of the light that is generated by light source LR, LG, LB, LY, and the ratio of these colors does not have filtered device RF, GF, BF, YF change.Or in other words, described color filter only needs to stop the light of unconnected light source.Now, the light that leaves light source LR, LG, LB, LY is exactly the primary colors of display DD.
Can only there be three light sources, to substitute four different light source LR, LG, LB, LY.Now, in color filter RF, GF, BF, YF is selected in order to allow at least a portion of light of at least two generations in light source LR, LG, LB, LY pass through.Alternately, can use one group of single source in the light source of all launching same spectra basically.In the present embodiment, primary colors is by the spectral distribution of the light of light source and the spectral filtering definition of color filter.
Pixel driver PDR will drive respectively signal r, g, b, y offer sub-pixel RP, GP, BP, YP to control the transmission of sub-pixel RP, GP, BP, YP.
Must be noted that each pixel need to be more than four sub-pixels if need to be more than four kinds of primary colors.How to obtain according to primary colors, can need more not homochromy light sources and/or color filter.Although R, G, B, Y refer to red, green, blue and Huang, in fact other colors also can be used.
Fig. 7 shows the display device with DMD and colour wheel.Broad spectrum light source L1 generates the light beam LI1 that falls on rotation colour wheel CW.Colour wheel CW has color filter section FG, FR, FB, FY.The light beam LC1 that leaves colour wheel CW falls on the sub-pixel M 1 of the pixel Pi of DMD display, M2, M3, M4 in chronological order.All sub-pixel M 1 to M4 can be identical micro mirrors, and according to the angle of the described micro mirror of image adjustment to be shown.
Fig. 8 shows the high-level flow of the method for further design display.At step S1, determine the brightness LU of object RO.Usually, these brightness LU that are used for not homochromy object RO are determined once, then are stored in table.Alternately, these brightness LU can find in documents and materials and can use at step S2 immediately.At step S2, select primary colors RW, GW, BW, YW to make to utilize basically to be complementary with the brightness LU of the spectrum that is reflected by the object RO with respective color by the high-high brightness BR of the reproducible different colours of colour gamut of primary colors RW, GW, BW, YW definition.If the preferred different white that adopts high-high brightness for the design of display, the so necessary different spectrum that use light source LI2.For example, for the D65 white point, corresponding spectrum of sunlight D65 is used as LI2.For the white point of 8600K, use to have temperature and be the corresponding blackbody radiation spectrum of 8600K.
If brightness LU must be determined, at step S10, the light LI2 illumination that reflecting object RO is generated by wideband light source L2.At step S11, measure by the brightness LU that has the reflectance spectrum that the reflecting object RO of 100% reflectivity basically reflects at the different wave length place, and calculate corresponding colourity λ 0 and brightness LU.At step S12, fixed brightness LU is stored for use.Alternately, if know, brightness LU can directly be stored and no longer be needed step S10 and S11.
Fig. 9 shows the process flow diagram of an embodiment of the method for design display.In the present embodiment, step S2 operation is as follows.At first, select the white point of a group of primary colors RW, GW, BW, YW and expectation at step S20.Selected primary colors RW, GW, BW, YW and selected white point also are generically and collectively referred to as PR.At step S21, calculate the ratio of selected primary colors RW, GW, BW, YW to obtain the white point of expectation.Then, equally at step S21, for all primary colors RW, GW, BW, YW and all secondary colours calculate high-high brightness BR.Described secondary colour refers to have by mixing the resulting color of primary colors RW, GW, BW, YW of high-high brightness BR.Determine or the brightness LU of retrieval and primary colors RW, GW, BW, YW and the corresponding reflecting object of secondary colour from storage medium.
At step S22, brightness value BR and the corresponding brightness LU that calculates compared.At last, at step S23, according to match-on criterion MC, judge whether brightness value BR mates with brightness LU basically.If one group of selected primary colors RW, GW, BW, YW does not satisfy match-on criterion MC, this algorithm proceeds to step S20 and selects another group primary colors RW, GW, BW, YW.If one group of selected primary colors RW, GW, BW, YW satisfies match-on criterion MC, this group primary colors becomes the candidate in display to be performed, and is stored at step S24.
In case found primary colors RW, GW, BW, the YW of one group of coupling, described algorithm just can stop.Alternately, this algorithm can be sought more than one group or even primary colors RW, GW, BW, the YW of all group couplings.If primary colors RW, GW, BW, the YW of more groups of couplings can use, can be chosen in that group primary colors that the enforcement aspect in display has best prospect.What for example, that emphasis considers is for obtaining the efficient of coupling primary colors RW, GW, BW, the needed hardware of YW.Alternately, best group can be that group with maximum gamut.
Must be noted that alternative primary colors and secondary colour or except primary colors and secondary colour, can select other colors, and be that they compare relevant brightness value BR and brightness LU.Selected color should realize with selected primary colors RW, GW, BW, YW.Although mentioned four kinds of primary colors RW, GW, BW, YW, identical algorithm also can be applied to be less than or more than the situation of four kinds of primary colors RW, GW, BW, YW.In addition, although four kinds of primary colors have used letter r (red), G (green), B (indigo plant) and Y (Huang), other colors also can be chosen as primary colors.
The example of match-on criterion can be: the brightness of pixel color is positioned at 80%～120% the scope of the brightness LU of the object RO with same color.Concerning different colors, this scope can be different.Alternately, as reference Figure 11 description, can the use experience method.Typically, error must be in ± 10%.
Figure 10 shows the process flow diagram of an embodiment of the method for design display.In the present embodiment, step S2 operation is as follows.
At first, at step S25, select one group of primary colors RW, GW, BW, YW.Selected primary colors RW, GW, BW, YW also can be generically and collectively referred to as PR.At step S26, define one group of checkpoint CP.These checkpoints CP is the color in display color gamut, at these colors place, must check match condition.For example, these checkpoints CP is that red primaries, green primary color and blue primary (RW, GW, BW), yellow secondary colour, pinkish red secondary colour and blue or green secondary colour (are respectively RW+GW, RW+BW, GW+BW) colourity, and the colourity (for example D65) of preferred white point.
At step S27, determine or retrieve from storage medium the corresponding bright BR of checkpoint CP.At step S28, determine or from the brightness LU of storage medium retrieval with the corresponding reflecting object RO of checkpoint CP.At step S29, the ratio between the brightness of calculation display primary colors RW, GW, BW, YW.
At step S30, according to match-on criterion MC, judge whether brightness value BR mates with brightness LU basically.If one group of selected primary colors RW, GW, BW, YW does not satisfy match-on criterion MC, algorithm proceeds to step S25 and selects another group primary colors RW, GW, BW, YW.If one group of selected primary colors RW, GW, BW, YW has satisfied match-on criterion MC, this group primary colors becomes the candidate that will implement in display, and is stored at step S31.Can define a scope, and select primary colors in described scope for each primary colors RW, GW, BW, YW.
In case found primary colors RW, GW, BW, the YW of one group of coupling, described algorithm just can stop.Alternately, this algorithm can be sought more than one group or even primary colors RW, GW, BW, the YW of all group couplings.If primary colors RW, GW, BW, the YW of more groups of couplings can use, can select its enforcement in display to have that group primary colors of best prospect.What for example, that emphasis considers is for obtaining the efficient of coupling primary colors RW, GW, BW, the needed hardware of YW.Perhaps the size according to colour gamut obtains best primary color set, and colour gamut is the bigger the better.In one embodiment, at colourity place, checkpoint, the error of display brightness BR and reflection colour brightness LU is minimized.This error minimize can be by selecting the best colourity of primary colors RW, GW, BW, YW in allowed limits, and/or realize by the brightness that changes them.The brightness of primary colors can pass through to change spectrum backlight, or changes by the transmission spectrum that changes color filter.Error can for example be defined as the root-mean-square error of luminance difference, wherein, before calculating luminance difference, log10 is in each brightness processes.Usually, concerning good display design, error should be less than ± 10%.
Must be noted that alternative primary colors and secondary colour or except primary colors and secondary colour, can select other colors, and be that they compare relevant brightness value BR and brightness LU.Selected color should realize with selected primary colors RW, GW, BW, YW.Although only mention four kinds of primary colors RW, GW, BW, YW, identical algorithm also can be applied to be less than or more than the situation of four kinds of primary colors RW, GW, BW, YW.In addition, although four kinds of primary colors have used letter r (red), G (green), B (indigo plant) and Y (Huang), other colors also can be chosen as primary colors.
Other examples of match-on criterion can be: the brightness of pixel color is positioned at 80%～120% the scope of the brightness LU of the object RO with same color.For different colors, this scope can be different.Alternately, as reference Figure 11 description, can the use experience method.Usually error is in ± 10%.
Figure 11 shows the process flow diagram according to an embodiment of the method for design display.At step S25, for example select primary colors RW, GW, BW, YW by operating personnel.White point can be preset, and perhaps also can be selected by operating personnel.At step S26, use at step S25 selected primary colors RW, GW, BW, YW and white point to show test pattern IM.At step S27, one group of observer watches the image of demonstration, and if in this group, at least 90% observer does not observe irritating significant or identifiable brightness puppet and resembles in image, the brightness BR of pixel color is considered to basically mate with brightness LU.In fact, test pattern can be the performance that appears at equally the real world sight at observer place, and if in this group, at least 90% observer does not observe irritating obvious or identifiable difference between the brightness of color and corresponding brightness, the brightness BR of pixel color is considered to basically mate with brightness LU.
Figure 12 shows another process flow diagram of the method for design display.Described at least four kinds of primary colors RW, GW, BW, the YW colourity by one of changing in primary colors RW, GW, BW, YW at least, or be selected by increasing extra primary colors.
At step S30, Color Gamut Mapping is applied in the input test picture signal IS with one group of predetermined different colours.At step S31, check the brightness BR in response to the shown different colours of input test image I S.At step S32, the brightness BR that the colourity that one of changes in primary colors RW, GW, BW, YW at least is complementary with the brightness LU that obtains basically with corresponding reflectance spectrum RS.Alternately, or additionally, another kind of primary colors is added in the primary colors that has existed to obtain brightness BR, and this brightness BR basically and cause being complementary with the brightness LU of the corresponding reflecting spectrum RS of one of primary colors that produces relatively large deviation between coupling brightness LU.For example, if a too high brightness BR detected for the brightness LU of particular color, this color or the color close with this color are decided to be new primary colors.
Figure 13 shows the example of the colour gamut with basic coupling brightness.
The first colour gamut GA1 is defined by four kinds of primary colors R, YG, GC, B, their x, and y, the Y coordinate is respectively:
R1：?0.6717，0.3181，19.6
YG1：0.3564，0.6319，68.1
GC1：0.0959，0.6958，33.1
B1：?0.1429，0.0458，7.1
The second colour gamut GA2 is defined by five kinds of primary colors R, G, B, C, Y, their x, and y, the Y coordinate is respectively:
R2：0.6776，0.3153，17.1
G2：0.2115，0.7569，34.4
B2：0.1449，0.0486，7.1
C2：0.0215，0.6069，10.5
Y2：0.3681，0.6208，70.5
The 3rd colour gamut GA3 is by six kinds of primary colors R, G, B, C, M, Y, their x, and y, the Y coordinate is respectively:
R3：0.6658，0.3264，20.0
G3：0.2781，0.6653，66.9
B3：0.1468，0.0514，6.6
C3：0.0567，0.3292，9.9
M3：0.3407，0.0986，10.3
Y3：0.4308，0.5597，84.8
Should be noted in the discussion above that above-described embodiment unrestricted the present invention in order to explanation, and in the situation that do not depart from the scope of claims, those skilled in the art can design many alternative embodiment.
For example, if do not need accurate luminance compensation, look-up table 1 can comprise the accurate brightness of reflecting object.The approximate brightness of only storing reflecting object is just enough.For example, ± 10% precision may be enough.
As long as display color gamut is different from the input signal colour gamut, this color map can advantageously be implemented, and does not rely on the primary colors quantity of using in display.
Should be understood that, above-mentioned mapping techniques can be realized in different devices or software, for example, this mapping techniques can consist of the part of photograph process software, and this software can offer specific display with the data with the form storage relevant with device thereafter.This correction also can be used by professional service, for example by the signal of improvement is provided in the dedicated channel on the Internet, or as the signal of the improvement on storer (for example on memory stick can buy from the shop).Can also download and proofread and correct profile (for example LUT) to use on home computer, perhaps receive plug-in unit etc.
In claims, any reference marker that is placed in bracket all should not be construed as for limiting claim.Verb " comprises " and those elements except the element that is illustrated in the claims or step or the existence of step are not got rid of in the use of conjunction.The element of not doing the number restriction comprises one or more such elements.The present invention can be by comprising a plurality of discrete components hardware and by implementing through the computing machine of suitably programming.In enumerating the device claim of a plurality of devices, a plurality of can being included in same hardware branch in these devices.The statement certain measure does not represent that the combination of these measures can not advantageously be used in mutually different appurtenances.
Claims (17)
1. Color Mapping Approach, the method is mapped to output image signal (OS) for display (DD) with received image signal (I S), described display (DD) comprises the have three or more sub-pixels display pixel (Pi) of (RP, GP, BP, YP), described three or more sub-pixel (RP, GP, BP, YP) has the primary colors (RW, GW, BW, YW) of definition display color gamut (WG), and the method comprises:
Use has the expectation brightness (LU of the reflectance spectrum (RS) of the real-world objects of different colours, Y1), described different colours is corresponding to the different colourity (x0 in described display color gamut (WG), y0), wherein, described reflectance spectrum (RS) is the spectrum of the light that reflected by respective objects in real-world objects, and wherein, expectation brightness (LU, Y1) is the total amount by the light of corresponding real-world objects reflection
Described received image signal (IS) with the input pixel color that is defined by input brightness (Y) and input colourity (x, y) is carried out Color Gamut Mapping (2), to obtain to have by mapping brightness (Ym; Y) and the map image signal (MS) of corresponding mapping pixel color of mapping colourity (xm, ym) definition, described input pixel color is positioned at the input colour gamut that is different from described display color gamut (WG); And
Depend on described expectation brightness (LU, Y1) and described mapping brightness (Ym by use; Factor (the F1 of the difference Y); G) adjust (5) described mapping brightness (Ym; Y), to obtain than described mapping brightness (Ym) more near the output brightness (Ys) of described expectation brightness (Y1), wherein, described output image signal (OS) is by described mapping colourity (xm, ym) and described output brightness (Ys) definition.
2. Color Mapping Approach according to claim 1, wherein, the use of described expectation brightness (LU, Y1) comprises retrieval described expectation brightness (LU, Y1) from look-up table (1).
3. Color Mapping Approach according to claim 1, wherein, the use of described expectation brightness (LU, Y) comprises applied mathematical model, described mathematical model is designed to generate such expectation brightness (LU).
4. Color Mapping Approach according to claim 1 wherein, obtains spectrum by the light of described real-world objects reflection by measuring real-world objects by the preset light sources illumination.
5. Color Mapping Approach according to claim 4, wherein, described preset light sources is broad spectrum light source.
6. Color Mapping Approach according to claim 1, wherein, each expectation brightness (LU, Y1) is the maximum total amount of the light that is reflected basically.
7. Color Mapping Approach according to claim 1, wherein, the adjustment of described mapping brightness (Ym) comprises described mapping brightness (Ym) is restricted to and is essentially described expectation brightness (LU).
8. Color Mapping Approach according to claim 2, also comprise the input colourity (x by searching at described received image signal (IS) in described look-up table (1), y) the storage brightness (LU) of locating retrieve (6) other search brightness (Y2), and wherein, the adjustment (5) of described mapping brightness (Y) comprise by with at described mapping colourity (xm, ym) locate search brightness (Y1) with at described input colourity (x, y) the described factor (G) that the ratio between brightness (Y2) equates basically of searching of locating carries out convergent-divergent to described mapping brightness (Y).
9. according to claim 1 or 8 described Color Mapping Approachs, wherein, described Color Gamut Mapping (2) only is applied to Color Gamut Mapping described input colourity (x, y), and wherein, described mapping brightness (Ym; Y) be described input brightness (Y).
10. Color Mapping Approach according to claim 1, wherein, described Color Gamut Mapping (2) provides color enhancement.
11. Color Mapping Approach according to claim 10, wherein, described color enhancement is that saturation degree is strengthened.
12. Color Mapping Approach according to claim 1, wherein, described display (DD) is the multi-primary display with primary colors (RW, GW, BW, the YW) quantity greater than three.
13. color map circuit, for the output image signal that received image signal is mapped to for display (DD), described display (DD) comprises the have sub-pixel display pixel (Pi) of (RP, GP, BP, YP), described sub-pixel (RP, GP, BP, YP) has the primary colors (RW, GW, BW, YW) of definition display color gamut (WG), and this color map circuit comprises:
Expectation brightness unit, expectation brightness (LU for the reflectance spectrum (RS) that generates the real-world objects with different colours, Y1), described different colours is corresponding to the different colourities (x0, y0) in described display color gamut (WG), wherein, each described reflectance spectrum (RS) is the spectrum by the light of real-world objects reflection, and wherein, each described expectation brightness (LU, Y1) be total amount by the light of corresponding real-world objects reflection
Color Gamut Mapping device (2) is used for the described received image signal (IS) with the input pixel color that is defined by input brightness (Y) and input colourity (x, y) is carried out Color Gamut Mapping, to obtain to have by mapping brightness (Ym; Y) and the map image signal (MS) of corresponding mapping pixel color of mapping colourity (xm, ym) definition, described input pixel color is positioned at the input colour gamut that is different from described display color gamut (WG); And
Circuit tuning (5) is used for using and depends on described expectation brightness (LU, Y1) and described mapping brightness (Ym; The factor of the difference Y) (F1), to obtain than described mapping brightness (Ym) more near the output brightness (Ys) of described expectation brightness (Y1), wherein, described output image signal (OS) is by described mapping colourity (xm, ym) and described output brightness definition (Ys).
A 14. display (DD), comprise have sub-pixel display pixel (P i) and the color map circuit according to claim 13 of (RP, GP, BP, YP), described sub-pixel (RP, GP, BP, YP) has the primary colors (RW, GW, BW, YW) that has defined display color gamut (WG).
15. display according to claim 14 (DD) comprising:
The LCD display panel, this LCD display panel has the pixel (Pi) that comprises at least four sub-pixels (RP, GP, BP, YP), described at least four sub-pixels (RP, GP, BP, YP) have the relevant color filter (RF, GF, BF, YF) that is used for generating at least four kinds of described primary colors (RW, GW, BW, YW)
Driving circuit (PDR) is used for receiving described output image signal (OS), driving voltage being offered described at least four sub-pixels (RP, GP, BP, YP), and
Back light unit (LR, LG, LB, LY) is used for throwing light on described LCD display panel.
16. display according to claim 14 (DD), this display (DD) are be used to the colors sequence type display that shows described output image signal (OS).
17. a method that is used for the described display of design consideration claim 14, wherein, the method comprises:
Determine or use the brightness (LU) of (S1) reflectance spectrum (RS) that different colourities (λ 0) are located in described display color gamut (WG), wherein, described reflectance spectrum (RS) is to locate to have respectively the spectrum of the reflecting object of maximum reflectivity (RO) basically in described different colourities (λ 0), and
Select (S2) at least four kinds of described primary colors (RW, GW, BW, YW), in order to obtain the brightness (BR) of one group of selected pixel color in described display color gamut (WG), this brightness (BR) is complementary with the brightness (LU) of the reflectance spectrum (RS) of locating in described colourity (λ 0) basically, and described colourity (λ 0) is corresponding to the pixel color of described selected group.
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| PCT/IB2007/054058 WO2008044177A1 (en) | 2006-10-12 | 2007-10-05 | A color mapping method |
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| US9140607B2 (en) * | 2012-07-27 | 2015-09-22 | Imax Corporation | Observer metameric failure reduction method |
| US20140225912A1 (en) * | 2013-02-11 | 2014-08-14 | Qualcomm Mems Technologies, Inc. | Reduced metamerism spectral color processing for multi-primary display devices |
| CN104103043B (en) * | 2014-07-04 | 2017-02-15 | 上海理工大学 | Spatial gamut mapping method |
| CN106604024B (en) * | 2016-12-14 | 2018-07-17 | 北京集创北方科技股份有限公司 | Image processing method and its device |
| US11172172B2 (en) | 2016-12-30 | 2021-11-09 | Texas Instruments Incorporated | Efficient and flexible color processor |
| WO2019023835A1 (en) * | 2017-07-31 | 2019-02-07 | 华为技术有限公司 | Wide-colour-gamut image display method and device |
| CN107680556B (en) * | 2017-11-03 | 2019-08-02 | 深圳市华星光电半导体显示技术有限公司 | A kind of display power-economizing method, device and display |
| KR102496558B1 (en) * | 2018-08-02 | 2023-02-08 | 삼성디스플레이 주식회사 | Device and method for controlling color gamut, display device including the device for controlling color gamut |
| CN116348945A (en) * | 2020-11-02 | 2023-06-27 | 伊英克公司 | Method and apparatus for rendering color images |
| CN113365039B (en) * | 2021-06-03 | 2022-07-26 | 滨州学院 | Multi-screen display color correction method and system for flight simulator |
| CN113643651B (en) * | 2021-07-13 | 2022-08-09 | 深圳市洲明科技股份有限公司 | Image enhancement method and device, computer equipment and storage medium |
| CN116312414B (en) * | 2023-02-10 | 2023-11-03 | 荣耀终端有限公司 | Color switching method, device, medium and electronic equipment |
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