CN100361189C - Color conversion method and circuit - Google Patents

Abstract

The present invention relates to a color conversion method which comprises the following steps: a first correction value is added on a lightness maximum value among a red R, a green G and a blue B so that the maximum value becomes a new maximum value; a second correction value is subtracted from a lightness minimum value of the R, the G and the B so that the minimum value becomes a new minimum value; a third correction value is added on a lightness middle value of the R, the G and the B so that the middle value becomes a new middle value; a W value is arranged as the lightness minimum value of the R, the G and the B; the new maximum value, the new minimum value and the new middle value substitute the original maximum value, the original minimum value and the original middle value of the R, the G and the B so that the corrected R, the corrected G and the corrected B are obtained; the corrected R, the corrected G, the corrected B and the W are respectively regarded as an output red lightness value, an output green lightness value, an output blue lightness value and an output white lightness value.

Description

Color changeover method and circuit

Technical field

The present invention relates to a kind of color changeover method and circuit, particularly a kind of color changeover method of liquid crystal display applications and circuit.

Background technology

Pixel (pixel) configuration of tradition liquid crystal panel (LCD panel) is to form shades of colour with R (red), G (green), B (indigo plant) three primary colors colour mixture.Fig. 1 represents a pixel (pixel) is become by three kinds of original colors the example of four kinds of colors.In order to increase brightness, and under the situation that does not influence resolution, change the mode of original three kinds of colors into four kinds of colors.Color has increased the part of W, and promptly the higher sub-pixel (sub-pixel) of transmissivity makes the brightness of whole liquid crystal panel promote.This kind colour mixture mode is called many primary colors additive colo(u)r system, and colored filter (color-filter) the lifting color saturation that its advantage is to have solved because of liquid crystal panel causes the problem that whole liquid crystal panel luminous intensity descends that too much makes backlight that absorbs.

Jap.P. (Japan Patent P2001-1476660A) proposes a kind of R, G with input, R, the G that B is converted to output, the method for B.

The notion of this patent is, can keep original state in order to make color saturation, and Rout, Gout, Bout all subtract the minimum M in (RGB) among R, G, the B, add an offset again.This can cause and satisfy color saturation, but the brightness increase is very little.

Therefore, how designing a kind of new method, can increase the brightness of display panels, can take into account R, G, B color saturation again, is that industry is in demand.

Summary of the invention

Therefore purpose of the present invention is providing a kind of color changeover method and circuit exactly, is used for a LCD, and this color changeover method can increase the brightness of liquid crystal panel.

Another object of the present invention is that a kind of color changeover method and circuit are being provided, and this color changeover method can be kept the color saturation of liquid crystal panel, and colour cast is very little.

Another purpose of the present invention is that a kind of color changeover method and circuit are being provided, and can directly be additional on the LCD with the circuit pattern.

According to above-mentioned purpose of the present invention, a kind of color changeover method is proposed, be used for a LCD, this color changeover method comprises the following steps.Maximal value among one R, a G and the B is added one first modified value, and to become new maximal value, wherein R is an original red brightness value, and G is an original green brightness value, and B is an original blue brightness value, and first modified value is a positive number.

Minimum value among R, G and the B is deducted one second modified value, and to become new minimum value, wherein this second modified value is a positive number.Intermediate value among R, G and the B is added one the 3rd modified value, to become new intermediate value.One W value is set at minimum value among R, G and the B.Replace maximal value, minimum value and intermediate value among original R, G and the B with new maximal value, new minimum value and new intermediate value, and obtain revised R, revised G, revised B.Revised R, revised G, revised B and W are used as an output red brightness value, the green brightness value of an output, an output blue brightness value and an output white brightness value respectively.

According to purpose of the present invention, a kind of color conversion circuit is proposed, be used for a LCD.According to a preferred embodiment of the present invention, this color conversion circuit comprises a comparer, one first correction circuit, one second correction circuit, one the 3rd correction circuit and a W value generator.

Comparer is for maximal value, intermediate value and the minimum value differentiated among a R, a G and the B.Wherein R is an original red brightness value, and G is an original green brightness value, and B is an original blue brightness value.First correction circuit adds one first modified value with the maximal value among R, G and the B, and to become new maximal value, first modified value is a positive number.Second correction circuit deducts one second modified value with the minimum value among R, G and the B, and to become new minimum value, wherein second modified value is a positive number.

The 3rd correction circuit adds one the 3rd modified value with the intermediate value among R, G and the B, to become new intermediate value.W value generator is output as a W value with the minimum value among R, G and the B.Color conversion circuit replaces maximal value, minimum value and intermediate value among original R, G and the B with new maximal value, new minimum value and new intermediate value, and obtain revised R, revised G, revised B, and revised R, revised G, revised B and W are used as an output red brightness value, the green brightness value of an output, an output blue brightness value and an output white brightness value respectively.

The present invention has following advantage at least, and wherein each embodiment can have one or more advantages.Color changeover method of the present invention and circuit can increase the brightness of liquid crystal panel.Color changeover method of the present invention and circuit can be kept the color saturation of liquid crystal panel, and colour cast is very little.Color changeover method of the present invention and circuit can directly be additional on the LCD with the circuit pattern.

Description of drawings

For above and other objects of the present invention, feature, advantage and embodiment can be become apparent, being described in detail as follows of accompanying drawing:

Fig. 1 represents a pixel (pixel) is become by three kinds of original colors the example of four kinds of colors;

Fig. 2 A represents the brightness value of original (input) red (R) of an embodiment, green (G), blue (B);

Fig. 2 B represents red (R), green (G) after a function is handled, the brightness value of blue (B);

Fig. 2 C represent to add white brightness after red (R), green (G), the brightness value of blue (B); And

Fig. 3 represents an embodiment of a color conversion circuit 302 of the present invention.

The primary clustering symbol description

302: color conversion circuit 304: comparer

305:W value generator 306: decision circuitry

307: averaging circuit 308: multiplexer

312: the second correction circuits of 310: the first correction circuits

Correction circuit 316 in 314: the three: multiplexer

318：Rin 320：Gin

322：Bin 324：Rout

326：Gout 328：Bout

Embodiment

Before describing embodiments of the invention, the problem that needs earlier traditional RGBW display technique to be run into describes slightly.

If compare under the situation with sub-pixel (sub-pixel) brightness standard-sized sheet merely: in the panel of RGB, each pixel has three sub-pixels (sub-pixel), and each sub-pixel is through the luminance brightness of colorized optical filtering sector-meeting loss 2/3.So being calculated as of total brightness: 3* (1/3) * (1/3)=33% is 3 sub-pixels wherein, and each sub-pixel accounts for 1/3 area of panel, and each sub-pixel all passes through colored filter, remaining original (1/3) of output brightness.

Four sub-pixels are arranged in the RGBW panel, and wherein white sub-pixels (White sub-pixel) can not lost luminance brightness because of colored filter without colored filter.Other sub-pixel is through the luminance brightness of colorized optical filtering sector-meeting loss 2/3.

So being calculated as of total brightness: 3* (1/4) * (1/3)+1* (1/4) * 1=50%.Wherein 3* (1/4) * (1/3) represents R, G, B sub-pixel, and 1* (1/4) * 1 represents white sub-pixels (White sub-pixel).Through calculating, the panel of RGBW can increase by 50% than the panel high-high brightness of RGB.

(the RGBW panel is because sub-pixel numbers is more as if the loss of considering to add aperture opening ratio, aperture opening ratio can be littler than RGB panel) and white sub-pixels also have slightly optical power loss in fact, the appointment of RGBW panel high-high brightness increases by 30% than common RGB panel high-high brightness.Though and RGBW panel has the benefit that increases brightness than common RGB panel, has the saturated inadequately problem of colour cast and color.At colour mixture and R, G when the value of B has nothing in common with each other, when the brightness that rolls up white sub-pixels, then can cause colour cast serious.If the brightness increase of white sub-pixels is seldom the time, the panel overall brightness can increase inadequately.

Simply represent with mathematics:

Each color-ratio of input color is Rin: Gin: Bin.

Each color-ratio of output color is (Ro+Wo): (Bo+Wo): (Bo+Wo).

Optimal state is Rin: Gin: Bin=(Ro+Wo): (Bo+Wo): (Bo+Wo)

But in order to keep following formula, sometimes must be with the output brightness value toward descending.Or the output brightness value rises, but can sacrifice aberration (Rin: Gin: Bin ≠ (Ro+Wo): (Bo+Wo): (Bo+Wo)).

When each color-ratio has big difference, have the undersaturated problem of aberration and color.So suitable transfer equation formula is necessary, according to different R, G, B input signal, convert new R, G, B, W output signal to, and the result of conversion must expect and can keep the original color saturation that shows and increase brightness.

At the shortcoming of above-mentioned RGBW display technique, the invention provides suitable conversion formula.Under same backlight situation, can increase the brightness of panel and keep the original color saturation that shows.And can narrate in the back and explain in detail, this algorithm can more many brightness and can be littler in the side-play amount of aberration than the algorithm increase of having delivered at present.

In one embodiment, calculation method of the present invention comprises:

1. handle earlier, produce Min (RGB) i.e. minimum (RGB), Max (RGB) i.e. maximum (RGB), Middle (RGB) i.e. middle (RGB) and Average (RGB) i.e. on average (RGB) at the input data (data input) of original red brightness value R, original green brightness value G, original blue brightness value B.

2. original red brightness value R, original green brightness value G, original blue brightness value B input data are judged, which is a maximal value to judge input signal, which is a minimum value, and different situations is brought different formula into and calculated, and the input data is classified handle earlier.

3. the input signal at maximum adds a function (first modified value), subtracts a function (second modified value) at the input signal of minimum, makes when adding the brightness of white, and the output color can not produce too many deviation with original input color.In one embodiment, this function=function (Input Data, Average (RGB), Min (RGB), Max (RGB), Middle (RGB))

Fig. 2 A represents the brightness value of original (input) red (R) of an embodiment, green (G), blue (B).The brightness ratio of the RGB of original input is R: G: B=50: 30: 20=1: 0.6: 0.4

Earlier input signal is judged maximal value will add a function, to become new maximal value; Minimum value will subtract a function, to become new minimum value; Intermediate value also needs to carry out function according to numerical values recited and handles, to become new intermediate value; (for example adding one the 3rd modified value).W (white brightness value) also can produce via the minimum value of R, G, B.Replace maximal value, minimum value and intermediate value among original R, G and the B with new maximal value, new minimum value and new intermediate value, and obtain revised R, revised G, revised B.Then revised R, revised G, revised B and W are used as an output red brightness value, the green brightness value of an output, an output blue brightness value and an output white brightness value respectively.Fig. 2 B represents red (R), green (G) after a function is handled, the brightness value of blue (B).After the function correction, the brightness ratio of RGB is R: G: B=58: 28: 12.This moment, W was 20.

Fig. 2 C represent to add white brightness after red (R), green (G), the brightness value of blue (B).After adding white brightness individually, each color-ratio of in fact exporting color is (Ro+Wo): (Bo+Wo): (Bo+Wo).(Ro+Wo)∶(Bo+Wo)∶(Bo+Wo)＝(58+20)∶(28+20)∶(12+20)＝78∶48∶32＝1∶0.62∶0.41。Brightness obviously increases, and each color-ratio is also very approaching with original input value.

Below more be described in detail the conversion method that how original RGB is converted to new RGBW with formula.This conversion method can make the RGBW panel increase its brightness, and keeps the original color saturation degree.

Conversion method is as follows:

1. make the gray scale numerical value called after R of the R of input.

The gray scale numerical value called after G of the G of order input.

The gray scale numerical value called after B of the B of order input.

2. through after the equation conversion, make the gray scale numerical value called after R ' of the R of output. the gray scale numerical value called after G ' of the G of order output;

The gray scale numerical value called after B ' of the B of order output;

The gray scale numerical value called after W ' of the W of order output.

3. $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3}.$

4. select R earlier, G, maximal value=Max among the B (RGB)

Minimum value=Min (RGB)

Intermediate value .=Mid (RGB)

5. order

$\mathrm{New}\_\max =\mathrm{Max}\left(\mathrm{RGB}\right)+\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$

6. order

$\mathrm{New}\_\min =\mathrm{Min}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$

7. order

$\mathrm{New}\_\mathrm{mid}=\mathrm{Mid}\left(\mathrm{RGB}\right)+\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Mid}\left(\mathrm{RGB}\right)-\mathrm{Average}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$

8. if R is a maximal value among R, G, the B, make R '=New_max;

If R is a minimum value among R, G, the B, make R '=New_min;

If R is an intermediate value among R, G, the B, make R '=New_mid.

9. if G is a maximal value among R, G, the B, make G '=New_max;

If G is a minimum value among R, G, the B, make G '=New_min;

If G is an intermediate value among R, G, the B, make G '=New_mid.

10. if B is a maximal value among R, G, the B, make B '=New_max;

If B is a minimum value among R, G, the B, make B '=New_min;

If B is an intermediate value among R, G, the B, make B '=New_mid.

11.W’＝Min(RGB)。

In the above-mentioned steps $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$ It is first modified value; $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$ It is second modified value; $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Mid}\left(\mathrm{RGB}\right)-\mathrm{Average}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$ It is the 3rd modified value.

The present invention also provides a kind of color conversion circuit 302, is used for a LCD.Fig. 3 represents an embodiment of a color conversion circuit 302 of the present invention.Red (R), green (G) of input, blue (B) signal are represented its brightness value with Rin 318, Gin 320, Bin 322 respectively.Comparer 304 is for maximal value Max (RGB), the intermediate value Mid (RGB) and the minimum M in (RGB) that differentiate among Rin 318, Gin 320, the Bin 322.Comparer 304 output Max (RGB), Mid (RGB) and Min (RGB) give first correction circuit 310, second correction circuit 312 and the 3rd correction circuit 314.W value generator 305 selection Min (RGB) are used as the W value and export.

Averaging circuit 307 calculates:

$\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3};$

Wherein Average (RGB) calculates first modified value, second modified value and the 3rd modified value for first correction circuit 310, second correction circuit 312 and the 3rd correction circuit 314 respectively.

First correction circuit 310 carries out:

$\mathrm{New}\_\max =\mathrm{Max}\left(\mathrm{RGB}\right)+\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$ Calculating;

Second correction circuit 312 carries out:

$\mathrm{New}\_\min =\mathrm{Min}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$ Calculating;

The 3rd correction circuit 314 carries out:

$\mathrm{New}\_\mathrm{mid}=\mathrm{Mid}\left(\mathrm{RGB}\right)+\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Mid}\left(\mathrm{RGB}\right)-\mathrm{Average}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}$ Calculating.

Decision circuitry (judgment block) 306 receives Rin 318, Gin 320, Bin 322 and judges that how Rin 318, Gin 320, Bin 322 being classified to first correction circuit 310, second correction circuit 312 and the 3rd correction circuit 314 carries out computing.Multiplexer 308 receives Rin 318, Gin 320, Bin 322 and is dispensed to first correction circuit 310, second correction circuit 312 and the 3rd correction circuit 314.The value of first correction circuit 310, second correction circuit 312 and 314 computings of the 3rd correction circuit is distributed via multiplexer 316 again, to export the brightness of correct red Rout 324, green Gout 326, blue Bout 328.The details of these color conversion circuit 302 computings repeats no more in this with above-mentioned color changeover method.

With Rin=50; Gin=30; Bin=20 is used as comparative example.Actual computation the present invention and two prior art method compare.Rin∶Gin∶Bin＝1∶0.6∶0.4。

Of the present invention resulting in:

Ro＝58

Go＝28

Bo＝12

Wo＝20

(Ro+Wo)∶(Bo+Wo)∶(Bo+Wo)＝(58+20)∶(28+20)∶(12+20)＝78∶48∶32＝1∶0.62∶0.41

Ro+Go+Bo+3*Wo＝158

Jap.P. (Japan Patent P2001-1476660A) results in

Ro＝50

Go＝22

Bo＝8

Wo＝20

(Ro+Wo)∶(Bo+Wo)∶(Bo+Wo)＝(50+20)∶(22+20)∶(8+20)＝70∶42∶28＝1∶0.6∶0.4

Ro+Go+Bo+3*Wo＝140

Other one piece of paper (40.5L:Late-News Paper:TFT_LCD with RGBW ColorSystem) results in:

Ro＝50

Go＝30

Bo＝20

Wo＝40

(Ro+Wo)∶(Bo+Wo)∶(Bo+Wo)＝(50+40)∶(30+40)∶(20+40)＝90∶70∶60＝1∶0.78∶0.67

Ro+Go+Bo+3*Wo＝220

Comparison by above-mentioned algorithm can find that resulting in of the present invention and Jap.P. (Japan PatentP2001-1476660A) all meets the demand of aberration, but the display brightness performance is with the present invention preferable (about many 10%).And the algorithm of other one piece of paper, though can roll up panel luminance, colour cast is bigger.

The present invention has following advantage at least, and wherein each embodiment can have one or more advantages.Color changeover method of the present invention and circuit can increase the brightness of liquid crystal panel.Color changeover method of the present invention and circuit can be kept the color saturation of liquid crystal panel, and colour cast is very little.Color changeover method of the present invention and circuit can directly be additional on the LCD with the circuit pattern.

Though the present invention with preferred embodiment openly as above; right its is not that any those skilled in the art are under the situation that does not break away from the spirit and scope of the present invention in order to qualification the present invention; can change and modification, so protection scope of the present invention is as the criterion with the claim institute restricted portion that is proposed.

Claims (11)

1. a color changeover method is used for a LCD, and this color changeover method comprises:

Maximal value among R, G and the B is added first modified value, and to become new maximal value, wherein this R is an original red brightness value, and this G is an original green brightness value, and this B is an original blue brightness value, and this first modified value is a positive number;

Minimum value among this R, this G and this B is deducted second modified value, and to become a new minimum value, wherein this second modified value is a positive number;

Intermediate value among this R, this G and this B is added the 3rd modified value, to become a new intermediate value;

The W value is set at minimum value among this R, this G and this B; And

Replace maximal value, minimum value and intermediate value among original R, G and the B with this new maximal value, this new minimum value and this new intermediate value, and obtain revised R, revised G, revised B, with revised this R, revised this G, revised this B and this W be used as the output red brightness value respectively, export green brightness value, output blue brightness value and output white brightness value.

2. color changeover method as claimed in claim 1, wherein, this first modified value equates with this second modified value.

3. color changeover method as claimed in claim 1, this first modified value is $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)},$ Wherein $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3},$ Min (RGB) is the minimum value among this R, this G and this B.

4. color changeover method as claimed in claim 1, this second modified value is $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)},$ Wherein $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3},$ This Min (RGB) is the minimum value among this R, this G and this B.

5. color changeover method as claimed in claim 1, the 3rd modified value is $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Mid}\left(\mathrm{RGB}\right)-\mathrm{Average}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)},$ Wherein $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3},$ This Min (RGB) is the minimum value among this R, this G and this B, and this Mid (RGB) is the intermediate value among this R, this G and this B.

6. a color conversion circuit is used for a LCD, and this color conversion circuit comprises:

Comparer, for maximal value, intermediate value and the minimum value differentiated among R, G and the B, wherein this R is an original red brightness value, and this G is an original green brightness value, and this B is an original blue brightness value

First correction circuit adds first modified value with the maximal value among this R, this G and this B, and to become new maximal value, this first modified value is a positive number;

Second correction circuit deducts second modified value with the minimum value among this R, this G and this B, and to become new minimum value, wherein this second modified value is a positive number;

The 3rd correction circuit adds the 3rd modified value with the intermediate value among this R, this G and this B, to become new intermediate value;

W value generator is output as the W value with the minimum value among this R, this G and this B; And

Wherein this color conversion circuit replaces maximal value, minimum value and intermediate value among original R, G and the B with new maximal value, new minimum value and new intermediate value, and obtain revised R, revised G, revised B, and with revised this R, revised this G, revised this B and this W be used as the output red brightness value respectively, export green brightness value, output blue brightness value and output white brightness value.

7. color conversion circuit as claimed in claim 6, wherein, this first modified value equates with this second modified value.

8. color conversion circuit as claimed in claim 6 more comprises an averaging circuit, for calculating:

$\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3};$

Wherein this Average (RGB) calculates this first modified value, this second modified value and the 3rd modified value for this first correction circuit, this second correction circuit and the 3rd correction circuit respectively.

9. color conversion circuit as claimed in claim 6, wherein this first correction circuit calculates

$\mathrm{New}\_\max =\mathrm{Max}\left(\mathrm{RGB}\right)+\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)};$

Wherein New_max be new maximal value, $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3},$ Max (RGB) is the maximal value among this R, this G and this B, and Min (RGB) is the minimum value among this R, this G and this B, and this first modified value is $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}.$

10. color conversion circuit as claimed in claim 6, wherein this second correction circuit calculates

$\mathrm{New}\_\min =\mathrm{Min}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)};$

Wherein New_min be new minimum value, $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3},$ This Min (RGB) is the minimum value among this R, this G and this B, and this second modified value is $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Average}\left(\mathrm{RGB}\right)-\mathrm{Min}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}.$

11. color conversion circuit as claimed in claim 6, wherein the 3rd correction circuit calculates

$\mathrm{New}\_\mathrm{mid}=\mathrm{Mid}\left(\mathrm{RGB}\right)+\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Mid}\left(\mathrm{RGB}\right)-\mathrm{Average}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)};$

Wherein New_mid be new intermediate value, $\mathrm{Average}\left(\mathrm{RGB}\right)=\frac{R+G+B}{3},$ This Min (RGB) is the minimum value among this R, this G and this B, and this Mid (RGB) is the intermediate value among this R, this G and this B, and the 3rd modified value is $\mathrm{Min}\left(\mathrm{RGB}\right)\×\frac{\mathrm{Mid}\left(\mathrm{RGB}\right)-\mathrm{Average}\left(\mathrm{RGB}\right)}{\mathrm{Average}\left(\mathrm{RGB}\right)}.$

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