CN1168285C - Color-strengthening image processing device and method - Google Patents

Abstract

The present invention relates to a device and a method for strengthening pixel color, wherein the device comprises a first circuit, a second circuit, a third circuit and a fourth circuit. In a better concrete embodiment, the device also comprises a fifth circuit. The first circuit provides, determines and outputs a first reference value X. The second circuit inputs the reference value X and a three-component (R, G and B), and the three-component (R, G and B) respectively subtracts the reference value X to obtain the value of (R-X), (G-X) and (B-X). The third circuit is used for inputting the value of (R-X), (G-X) and (B-X), and the value of (R-X), (G-X) and (B-X) is enlarged or reduced according to a zoom factor S in a proportion, so the value of S*(R-X), S*(G-X) and S*(B-X) is generated. The fourth circuit adds the value of S*(R-X), S*(G-X) and S*(B-X) to the three-component (R, G, B) respectively, and three enhanced components (R', G' and B') are generated.

Description

Strengthen the device and method that color image is handled

Technical field

The present invention relates to the color image treatment technology, particularly strengthen the color image processing unit and the method for color.

Background technology

HSV (hue, saturation, value) or HSB (brightness) model is an interface of being selected the red green blue tricolor model by a kind of more intuitive manner that A.R.Smith (1978) proposes for hue, saturation.This color space is the hexagonal pyramidal body.The HSV cone is the cubical non-linear conversion of a RGB, and is considered to (perceptual) model of a sensibility.The meaning of ' sensibility ' is meant and has the characteristic that more is similar to human cognitive color, and is not to refer to that color space is sensuously linear (linear).The non-linear sensation (non-linear) of this rgb space still persists in the HSV space.Particularly, with respect to the change of angle, changing into of tone (hue) sensation is nonlinear.

When the user need do control or selection to a color with aesthstic or similar basis, the HSV model can be used to any relevant occasion.Use is based on the parameter of sensibility, and as the RGB display of tone, saturation (saturation) and lightness (value/brightness), the HSV model makes the part or all of scope of control one RGB screen become possibility.This expression can be easily and can be expectedly set up user's interface by the mode that one of changes in three parameters.When the parameter of these sensibility is used, as make brighter, the dimer or more operation of yellowing of color X, can be than determining the combination that how to change RGB to be easy to many.

This HSV model be built in polar coordinates (r, θ, z) on, but not flute card (Cartesians) coordinate.Tone (H), or claim deep or lightly, be to represent with the θ angle, scope is 0 ° to 360 °.This hexagonal summit is with 60 ° of separations, red θ be 60 ° the place, yellow θ be 60 ° the place, green be 120 ° place at θ, and dark green be 180 ° place at θ, and complementary colours each with 180 ° separately.

Distance to the z axle is represented saturation (S): the color amount of existence.S is by 0 to 1.Saturation is represented the ratio of the purity (purity) of a tone in the HSV model.S=1 represents that this tone is maximum purity, and when S=0.25, tone is 1/4th purity, and when S=0, is GTG.

V is the lightness of HSV, is worth to 1 value of hexagonal pyramid bottom by 0 of the top of hexagonal pyramid.V=0 representative black (blackness), and during V=1, color then has maximum intensity (intensity), when V=1 and S=1, is pure hue (pure hue), pure white (whiteness) then can obtain in the position of V=1 and S=0.

If the user can adjust HSV color parameter: H, S, V by mapping software, then these parameters can be converted into the RGB set point, for control RGB color/graphics.For determining required operation in this conversion, how we will obtain the HSV hexagonal pyramid by RGB cube (cube) with following well known algorithmic descriptions.

Black (initial point) is to the z axle of white diagonal corresponding to the HSV hexagonal pyramid in the RGB cube.The cubical sub-cube of each RGB is corresponding to a hexagon in section zone of HSV hexagonal pyramid.On any section, to all radial transmission lines on arbitrary summit, identical V (lightness) is arranged all on this HSV hexagon and by the z axle.For arbitrary group of rgb value, V equals the maximum in this class value.HSV point corresponding to this RGB class value is to be positioned on the hexagon in section with V value.S is the saturation of HSV, is the relative distance of this position distance z axle.H is the tone of HSV, and mat calculates this point and is positioned at the hexagonal relevant position to a sextant (Sextant) of HSV and tries to achieve its value.Following program (writing with the C language) provides a well known algorithm that the RGB class value is mapped to this corresponding HSV value.

#include＜math.h＞　　#define MIN(a，b)(a＜b？a：b)　　#define MAX(a，b)(a＞b？a：b)　　#define NO_HUE-1void rgbToHsv(float r，float g，float b，float*h，float*s，float*v)(　　    float max＝MAX(r，MAX(g，b))；　　    float min＝MIN(r，MIN(g，b))；　　    float delta＝max-min；        <!-- SIPO <DP n="2"> -->        <dp n="d2"/>　　   *v＝max；　　   if(max！＝0.0)*s＝delta/max；　　   else*s＝0.0；　　   if(*s＝＝0.0)*h＝NO_HUE；　　else{　　   if(r＝＝max)     *h＝(g-b)/delta；　　   else if(g＝＝max)     *h＝2+(b-r)/delta；　　   else if(b＝＝max)     *h＝4+(r-g)/delta；　　   *h*＝60.0；　　   if(*h＜0)*h+＝360.0；　　   *h/＝360.0；　　}}

Make that max is a maximum in red, green and the blue color component, make that min is a minimum value in red, green and the blue color component, make delta equal max and deduct min, and according to the HSV model, saturation is defined as delta/max.

To a specific pixel, suppose that this correspondence color component has the relation of one R＞G＞B.So this color tone angle is represented as θ, wherein,

And this color saturation is represented as Ω, wherein,

$\mathrm{\Ω}=\frac{(R-B)}{R}$

Summary of the invention

The purpose of this invention is to provide a kind of method and device that strengthens color image that computer graphics and video signal are used.

Another object of the present invention is under the situation that does not change the color tone, adjusts the saturation of a pixel in the computer graphics.

Provide a kind of device and method that strengthens pixel color at this, its specific embodiment comprises one first circuit, a second circuit, a tertiary circuit and one the 4th circuit.In a preferred embodiment, this device also comprises one the 5th circuit.This first circuit decision is also exported a reference value X.This second circuit import this reference value X and three-component (R, G, B), and with this three-component (R, G B) deduct this reference value X respectively, to obtain (R-X), (G-X) and value (B-X).This tertiary circuit input (R-X), (G-X) and value (B-X), and utilize a zoom factor S to scale (R-X), (G-X) and value (B-X) to be done to amplify or dwindle, to produce the value of S* (R-X), S* (G-X) and S* (B-X).The 4th circuit is added to the value of this S* (R-X), S* (G-X) and S* (B-X) this three-component respectively, and (R, G B), strengthen components (R ', G ', B ') to produce three.

By can further understanding the advantages and spirit of the present invention below in conjunction with the accompanying drawing detailed description of the invention.

Description of drawings:

Fig. 1 shows a preferred embodiment;

Fig. 2 shows another preferred embodiment.

Embodiment

For reaching the purpose that strengthens color, we wish and can keep increasing degree of saturation under the constant situation of color tone.The invention provides a kind of method to strengthen degree of saturation, as following equation (1).

In the equation (1), X can be the arbitrary value in R, G and the B value scope, and Scale is a selected zoom factor, and the color of this enhancing comprises a red components R _NEW, a green component G _NEWAn and blue component B _NEWWhen this zoom factor is timing, saturation can strengthen, and when this zoom factor when negative, saturation can reduce, and when if this zoom factor is zero, then saturation can not change.

Suppose this zoom factor for just, to a special pixel, if R＞G＞B, because the characteristic of linear scale, then R _NEW＞G _NEW＞B _NEWThis red component still is the maximum in the three-component.The new color tone angle of the color of this enhancing is with θ _NEWExpression is by the provable θ of following calculation _NEWIdentical with θ, when promptly doing to strengthen with equation (1), the color tone can't change.

According to above narration, new saturation Ω _NEWFollowing equation is represented.

${\mathrm{\Ω}}_{\mathrm{NEW}}=\frac{(R_{\mathrm{NEW}}-B_{\mathrm{NEW}})}{R_{\mathrm{NEW}}}$

Below calculation is provable, and when (R-B 〉=0), the saturation of color can strengthen.Be that equation (1) proposed by the invention can be realized purpose of the present invention.

${\mathrm{\Ω}}_{\mathrm{NEW}}-\mathrm{\Ω}=\frac{\left(R_{\mathrm{NEW}}{-B}_{\mathrm{NEW}}\right)}{R_{\mathrm{NEW}}}-\frac{(R-B)}{R}=\frac{R_{\mathrm{NEW}}*B-R{*B}_{\mathrm{NEW}}}{R_{\mathrm{NEW}}*R}$

$=\frac{[R+(R-X)*\mathrm{Scale}]*B-R*[B+(B-X)*\mathrm{Scale}]}{R_{\mathrm{NEW}}*R}$

$=\frac{-B*X*\mathrm{Scale}+R*X*\mathrm{Scale}}{R_{\mathrm{NEW}}*R}$

$=\frac{X*\mathrm{Scale}*(R-B)}{R_{\mathrm{NEW}}*R}\≥0$

According to above narration, by equation provided by the invention (1), when color saturation strengthens, this color tone will remain unchanged.

The default constant X that replacement is used in equation (1), second specific embodiment of the present invention is provided at color enhancement process in the rgb color space in order to equation down:

Wherein R, G and B are the original color component, R _NEW, G _NEWAnd B _NEWThe color component that be to strengthen, Scale is the enhancing degree, and f (R, G is B) for having one of R, G and B parameter function.

In a preferred embodiment, (R, G are that (B), wherein (R, G B) are minimum value among R, G and the B to this min to min for R, G B) to f.When implementing this embodiment, color strengthens equation and is:

Another replacement scheme is, ((B), wherein (R, G B) are maximum among R, G and the B to this max for R, G B) to be replaced by max for R, G with f.Or with f (R, G B) are replaced by median (middle) among R, G and the B, or (R, G B) are replaced by mean value (mean/average) among R, G and the B with f.We it be easy to show that when color saturation strengthens in the mode that is similar to equation of the present invention (2) or equation (3), the color tone will remain unchanged.

Because above-described enhancing process may cause this enhancing component to surpass the corresponding upper limit of each component, utilizes clamped computing (clamp operation) excessive to prevent (overflow).When surpassing this enhancing component value, clamped computing meeting limits this component value in this correspondence upper limit.

As shown in Figure 1, device of the present invention comprises one first circuit 10, a second circuit 12, a tertiary circuit 14 and one the 4th circuit 16.In a preferred embodiment, this device also comprises one the 5th circuit 18, and this color enhancement process is to be adjusted at former image in the rgb color space with a zoom factor, strengthens image to form one.This program can be handled each pixel in the rgb color space and not need the conversion of colour model.

These first circuit, 10 decisions are also exported a reference value X.This second circuit 12 this reference value of input X with (R, G, B), and with this three-component (R, G B) deduct this reference value X respectively, make in output to obtain (R-X), (G-X) and value (B-X).

These tertiary circuit 14 inputs (R-X), (G-X) and value (B-X), and, to scale this (R-X), (G-X) and value (B-X) are carried out convergent-divergent for utilizing a zoom factor S, to produce the value of S-(R-X), S* (G-X) and S* (B-X).The 4th circuit 16, (R, G B), strengthen components (R ', G ', B ') to produce three for respectively the value of this S* (R-X), S* (G-X) and S* (B-X) being added to this three-component.

Because above-described this enhancement process may cause this enhancings component (R ', G ', B ') to surpass a corresponding upper limit of each component, the 5th circuit 18 is excessive to prevent this component value in order to this clamped computing of execution.When surpassing this enhancing component value, this clamped computing meeting that the 5th circuit 18 is provided limits this color component value to export this upper limit.The 5th circuit 18 is output as (R ", G ", B ").

Minimum approximation method in equation (3) is used, and under the hypothesis of R＞G＞B, this equation (3) can be reduced to:

Be disclosed among Fig. 2 for a preferred embodiment of carrying out equation (4) function.

This device among Fig. 2 comprises one first circuit 21, one first multiplex (MUX) unit 23, a multiplication unit 25, one second multiplex (MUX) unit 27, an AND logical block 29, an arithmetic element 22 and a controller 24.

This first circuit 21 is imported the value of this R, G and B and is calculated and export (R-G), (G-B) and value (B-R) respectively.In a preferred embodiment, this first circuit 21 comprises three subtrators 210,212 and 214.Be somebody's turn to do (R-G), (G-B) and the position of positive negative value (sign) (B-R) and be input to this controller 24.

This first multiplex (MUX) unit 23 is connected in this first circuit 21, and corresponding one first selection signal 241, according to one first predetermined way, and optionally output (R-G), (G-B) and wherein two values (B-R).In a preferred embodiment, this first multiplex (MUX) unit 23 comprises one first multiplexer 231 and one second multiplexer 233.Therefore, this first multiplexer 231 outputs (R-G) or (G-B), and these second multiplexer, 233 outputs or output (B-R) or (G-B).For illustrative purposes, we suppose its R＞G of a pixel＞B now, and f (R, G, B) be min (R, G, B).

According to the hypothesis of this illustrative examples, the positive negative value of this that this controller 24 received position is (0,0,1).Utilize these positive negative value positions, this controller 24 is by a check table or its logical circuit, and the value of output one (1,1) is to this first selection signal 241.Under this assumption, these first multiplexer, 231 output (G-B) values, and these second multiplexer, 233 output (B-R) values.

This multiplicative identity 25 is connected to this first multiplex (MUX) unit 23, and selective property ground produces wherein two scale value of S* (R-G), S* (G-B) and S* (B-R), and wherein S is a default zoom factor.In a preferred embodiment, this multiplicative identity 25 comprises one first multiplier 251 and one second multiplier 253.Under above hypothesis, these first multiplier, 251 output S* (G-B) values, and these second multiplier, 253 output S* (B-R) values.

This second multiplex (MUX) unit 27 is connected to this multiplication unit 25, and corresponding one second selection signal 243, optionally exports the value of S* (R-G), S* (G-B) and S* (B-R).In a preferred embodiment, this second multiplex (MUX) unit 27 comprises one first multiplexer 271, one second multiplexer 273 and one the 3rd multiplexer 275.Utilize these positive negative value positions, this controller 24 is by a check table or its logical circuit, and the value of output one (1,0,1) is to this second selection signal 243.Under the hypothesis of this illustrative examples, the value of the value of this first multiplexer 271 output S* (B-R), this second multiplexer 273 output S* (G-B) and the value of the 3rd multiplexer 273 output S* (B-R).

This AND logical block 29 is connected to this second multiplex (MUX) unit 27, and corresponding one first control signal 245, optionally output (S* (B-R), S* (G-B), 0), (S* (R-G), 0, S* (G-B)) reaches (O, S* (R-G), S* (B-R)) one group of signal wherein.In a preferred embodiment, this AND logical block 29 comprises one the one AND unit 291, one the 2nd AND unit 293 and one the 3rd AND unit 295.Under the hypothesis of this illustrative examples, the information that 24 pairs of this controllers should positive and negative value position, the value that produces (1,1,0) is to this first control signal 245.Corresponding these values, the value of the value of an AND unit 291 output S* (B-R), the 2nd AND unit 291 output S* (G-B), and 295 outputs 0 of the 3rd AND unit.

This arithmetic element 22, be connected to this AND logical block 29 and import this three-component (R, G, B), and corresponding one second control signal 247, optionally output (R+S* (R-B), G+S* (G-B), B), (R+S* (R-G), G, B+S* (B-G)) one of them strengthens color component to reach (R, G+S* (G-R), B+S* (B-R)).In a preferred embodiment, this arithmetic element 22 comprises one first plus-minus unit 221, one second plus-minus unit 223 and one the 3rd plus-minus unit 225.Under the hypothesis of this illustrative examples, the information that 24 pairs of this controllers should positive and negative value position, the value that produces (1,0,0) is to this second control signal 247.Corresponding these values, the value of the value of this first plus-minus unit 221 output R+S* (R-B), this second plus-minus unit 223 output G+S* (G-B), and the 3rd plus-minus unit 225 output B.

The above desire that is described in detail is clearly narrated feature of the present invention and spirit, and non-in order to limit category of the present invention.The correction of various changes and equal item all should be contained by the present invention.Therefore, scope of the present invention should be according to following claim and the above broad interpretation that is stated as.

Claims (12)

1. method that strengthens pixel color, wherein this pixel color comprise three-component (R, G, B) respectively corresponding red, green and primary colors, the method includes the steps of:

(a) determine a reference value X;

(b) (R, G B) deduct this reference value X to obtain (R-X), (G-X) and value (B-X) with this three-component;

(c) utilize a zoom factor S, to (R-X), (G-X) and (B-X) carry out convergent-divergent respectively, with obtain component behind three convergent-divergents (Rs, Gs, Bs);

(d) ((R, G B), strengthen component to produce three Bs) to be added to this three-component for Rs, Gs with component behind this convergent-divergent respectively; And

(e) this three enhancings component is carried out a clamp computing.

2. the method for enhancing pixel color as claimed in claim 1, wherein this reference value X is the minimum value in this R, G and the B pixel.

3. the method for enhancing pixel color as claimed in claim 1, wherein this reference value X is the median in this R, G and the B pixel.

4. the method for enhancing pixel color as claimed in claim 1, wherein this reference value X is the maximum in this R, G and the B pixel.

5. the method for enhancing pixel color as claimed in claim 1, wherein this reference value X is the mean value in this R, G and the B pixel.

6. the method for enhancing pixel color as claimed in claim 1, wherein this convergent-divergent step is performed by the computing of S* (R-X), S* (G-X) and S* (B-X).

7. device that strengthens pixel color, wherein this pixel color comprise three-component (R, G, B) respectively corresponding red, green and primary colors, this device comprises:

One first circuit is for determining and export a reference value X;

One second circuit is for (R, G B) deduct this reference value X respectively, to obtain (R-X), (G-X) and (B-X) value with this three-component;

One tertiary circuit for utilizing a zoom factor S, carries out convergent-divergent to this (R-X), (G-X) and value (B-X) to scale, to produce S* (R-X), S* (G-X) and S* (B-X) value; And

One the 4th circuit, for respectively this S* (R-X), S* (G-X) and S* (B-X) value are added to this three-component (R, G, B), to produce three enhancing components; And

One the 5th circuit is for respectively this three being strengthened component clamp (clamping) in three higher limits.

8. the device of enhancing pixel color as claimed in claim 7, wherein this reference value X is the minimum value in this R, G and the B pixel.

9. the device of enhancing pixel color as claimed in claim 7, wherein this reference value X is the median in this R, G and the B pixel.

10. the device of enhancing pixel color as claimed in claim 7, wherein this reference value X is the maximum in this R, G and the B pixel.

11. the device of enhancing pixel color as claimed in claim 7, wherein this reference value X is the mean value in this R, G and the B pixel.

12. a device that strengthens pixel color, wherein this pixel color comprise three-component (R, G, B) respectively corresponding red, green and primary colors, this device comprises:

One first circuit is for calculating and export (R-G), (G-B) and value (B-R) respectively;

One first duplex circuit, this first duplex circuit is connected in this first circuit, and corresponding one first selection signal, and this first duplex circuit is according to one first predetermined way, and optionally output (R-G), (G-B) reach wherein two values (B-R);

One mlultiplying circuit, this mlultiplying circuit are connected in this first duplex circuit, and selective property ground produces S* (R-G), S* (G-B) and S* (B-R) two scale value wherein, and wherein S is a default zoom factor;

One second duplex circuit, this second duplex circuit is connected in this mlultiplying circuit, and corresponding one second selection signal, optionally exports the value of S* (R-G), S* (G-B) and S* (B-R);

One AND logical circuit, this AND logical circuit is connected in this second duplex circuit, and corresponding one first control signal, optionally output (S* (B-R), S* (G-B), 0), (S* (R-G), 0, S* (G-B)) reaches (0, S* (R-G), S* (B-R)) one group of signal wherein;

One computing circuit, this computing circuit be connected in this AND logical circuit and import this three-component (R, G, B), and corresponding one second control signal, optionally output (R+S* (R-B), G+S* (G-B), B), (R+S* (R-G), G, B+S* (B-G)) reaches one in (R, G+S* (G-R), B+S* (B-R)) and strengthen component; And

One clamp circuit is for carrying out the clamp computing to strengthening component.

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