CN102611897B - Method and system for carrying out vision perception high-fidelity transformation on color digital image - Google Patents

Abstract

The invention relates to the field of digital image processing, in particular to a method and a system for carrying out vision perception high-fidelity transformation on a color digital image. The method comprises the steps of: (1) acquiring L (Luminance), C (Saturation) and h (hue) of numerical values of pixel colors R (Red), G (Green) and B (Blue) of the color digital image in a CIELAB (International Commission on Lumination Laboratory) space; (2) merging the pixel colors into a hue plane and a luminance sequence; (3) completing expansion of C of the pixel colors; and (4) calculating parameters of the pixel colors of the image and a saturation value CLN obtained through expansion in (3) into values of R, G and B. According to an FECr (First Epos Color) algorithm provided by the invention, under the condition that the boundary of an image color space constituted by three primary colors, namely, red, green and blue, is not changed, colors, which are more sensitive for vision, in the image are calculated and are made relatively more increased in a visible light color vision perception property, colors which are relatively less sensitive for vision perception are calculated and are increased a little or maintained unchanged, and a nonlinear regulation method in such a way can be used for obtaining a relatively obvious effect approaching an actual scene watched in a visible light color space, for image watching.

Description

Color digital image is carried out to the method and system of visually-perceptible high-fidelity conversion

Technical field

The present invention relates to digital image processing field, relate to the method and system of color digital image being carried out to the conversion of visually-perceptible high-fidelity particularly.

Background technology

The trichromatic digital data acquisition of red, green and blue or color display is used to have many decades in the electronic device.Although its three primary colors are to make the faithful to as far as possible true scenery of display image for target selection, but due to restrictions such as material, technology and costs, still there is a big difference compared with the true scenery of viewing for the coloured image of up to the present viewing three primary colors display, full not comprising color, light sense is distinct not.

Be the color management for light of representative with ICC (International ColorConsortium international color consortium) specification, typical case uses gamma (gamma) index replacement red, green and blue three primary colors digital quantity to reach the object strengthening image.User finds, although color of image can be made to seem to seem full after application gamma index, light sense but seems poorer, and shade of color also there will be deviation.Anyone the colorimetry method using CIE (International Commission on Lumination Commission Internationale De L'Eclairage) to recommend, quantitatively can calculate the variation quantity using colour vision perception component before and after gamma index, prove that result is consistent with the above actual change seen.

Through the development of more than 20 years, the CAM (Color Appearance Model color appearance model) that CIE recommends now became recommeded international standard, plays an important role in colour reproduction field.But, no matter be CIECAM97s or CIECAM02 model, main research and prediction be all the change of external condition, as the quantitative effect to color observation effect such as reference white colour and brightness value change, model does not comprise space and the time response of human eye visual perception, does not comprise spatial domain and the time domain specification of image yet.It is that each pixel is regarded as separate color that current CAM is applied to Digital Image Processing, therefore with the reproduction of its digital picture instructed with copy and can't meet the high-quality needs of visually-perceptible authenticity.Recent relevant industry proposes to build iCAM (image Color Appearance Model image colored quantum noise), requires that model can process space and the time response of visually-perceptible and coloured image.Current iCAM model is also in the primary stage of research, and CIE does not yet discuss in detail and complete recommendation it.

The quantificational description of human eye visible light colors visually-perceptible spatial character fails all to complete so far, and main cause is the imperfection of basic data needed for visually-perceptible color quantizing.CIE recommended CIE1931RGB system in 1931, and the standard colorimetric observer's spectral tristimulus value described by it, has quantized the colour vision perception of the mankind since the dawn of human civilization first, and has therefore established the basis of modern colorimetry.But, some inherent characteristic of this system fail colorimetry theoretical research thereafter and technology application in be able to perfect.In CIE1931RGB system, spectral tristimulus value representative uses red, green and blue three primary colors to monochromatic number of matches various in equal-energy spectrum, and the spectrum locus coordinate calculated by its adaptation function is shown in Fig. 1.In figure, horseshoe curve represents spectrum locus, and the color in curve and the area included by the straight line of bottom was once takeed for the whole colors comprising the mankind and can see in for a long time.Triangle inner area represents red, green and blue three primary colors entirely on the occasion of the color gamut of coupling.Color containing three primary colors negative value should in the area beyond triangle and within curve.The difference be in the nature existing for use red, green and blue three primary colors match spectrum color of color negative value.The physical significance of negative value color is the opposite color of this non-negative color, is namely added with this non-negative color the color obtaining netrual colour color and is its opposite color.There is the statement of facts of negative value in adaptation function, if accurate match spectrum colour, need increase above opposite color on red, green and blue three primary colors basis.

Because the color shown with two monochrome and above multispectral look is the normality of mankind's perceived color simultaneously, by upper supposition, CIE1931RGB adaptation function does not comprise by red and blue primary on the occasion of combination and the visible light colors containing green primary color negative value, the color in this part form and aspect interval comprises bluish violet, purple and aubergine, account for nearly 1/3rd of human visual perception number of colors, wherein should have small part color chromaticity coordinate below the straight line of above Fig. 1.If with visible light colors vision perception characteristic for target carries out color high-fidelity simulation reappearance and the investigation and application copied, this part adaptation function should not lack.As the color matching function of modern colorimetry foundation stone, in CIELAB visually-perceptible homogeneous space, also cannot show the integral edge of visible light colors visually-perceptible spatial distribution, cause the quantificational description of the visible ray spatial character of human visual perception to fail so far all to complete.

Summary of the invention

The object of the invention is for color digital image provides the method for carrying out the conversion of high-fidelity visually-perceptible.According to technical scheme of the present invention, the visually-perceptible space of visible light colors and the method for correlated components equivalent is calculated by providing, realize being optimized expansion and mapping calculation to color digital image visually-perceptible component comparison visible light colors visually-perceptible spatial character, complete the high-fidelity visually-perceptible conversion of image.

Another object of the present invention is to provide the system of color digital image being carried out to the conversion of high-fidelity visually-perceptible.

" epic color one that method of the present invention and system belong to ^tM", (FirstEposColor ^tM), be called for short " poem look one ^tM", (FECr ^tM), mainly adjust the visually-perceptible intensity value of its each pixel color for significantly strengthening image high-fidelity perception, adjustment amount depends on intensity value and color self intensity value of brightness sequence in the visible light colors visually-perceptible space form and aspect plane equivalent color boundaries that this Color pair is answered.As a result, each pixel color of image while adding visually-perceptible saturation, maintain visually-perceptible form and aspect and brightness constant, and the saturation amplitude increased, is more conducive to high-fidelity and strengthens image vision perceived effect.

Representative color digital picture is the two-dimensional projection of the true scenery in visible light colors space at imaging plane, and therefore, image reproduction and the ideal effect copied should be as far as possible close to the perception to true scenery, and the high-fidelity of meaning reappears and copies.So, comprise according to algorithm of the present invention (FECr) and quantification statement is carried out to the visually-perceptible in visible light colors space.According to method of the present invention, the visible ray spatial character of the relatively above statement of the visually-perceptible saturation of image inherent colour is calculated expansion and mapped, obtains overall relatively maximum visible ray spatial characters for target with image and calculate the intensity value that each pixel increases.

Typical electronic device and color image color visually-perceptible space are much smaller than visible light colors visually-perceptible space, therefore, if directly with visible light colors space boundary for target adjustment color of image saturation, in some form and aspect planes, the increment most diverse of pixel color saturation will be caused, cause image deterioration.So, FECr algorithm according to the present invention is on the basis in complete description visible light colors visually-perceptible space, take into account the practical capacity of equipment and color of image visually-perceptible space saturation nonlinear extensions, calculate the form and aspect plane color equivalent border, visible light colors visually-perceptible space of optimization, and correct with the statistics of psychophysical method acquisition effect.Therefore, method according to the present invention is the effective ways obtaining the reproduction of color digital image high-fidelity and copy.

Method and system of the present invention can be used for the natural scene imagings such as photography, shooting, film, TV, video-game or any image and the dependent imaging equipment that are synthesized color by red, green and blue three primary colors by Practical computer teaching.

According to method of the present invention, the conversion of visually-perceptible high-fidelity is carried out to color digital image and comprises the following steps:

(1) obtain color digital image pixel color R, L, C and h numerical value of G and B numerical value in CIELAB space, wherein, h is hue angle, and L is brightness, C is saturation;

(2) pixel color merger enters form and aspect plane and brightness sequence,

Enter corresponding reference colours phase face with the merger of hue angle h value, enter corresponding bright sequence with lightness l value merger;

(3) expansion of pixel color saturation C is completed,

(3-1) determine that pixel color saturation maps flex point C _gL:

C _gL＝C _maxL1×X _S1

Wherein, C _maxL1for pixel color merger in equipment colour vision aware space enters the brightness sequence maximum saturation angle value of form and aspect plane, X _s1for the proportionality coefficient arranged, exemplary value scope 0.65-0.95;

(3-2) the saturation expansion ratio BI of this brightness sequence is calculated _l:

BI _L＝C _maxLd/C _maxL1

Wherein, C _maxLdfor the intensity value of same brightness sequence on pixel color identical form and aspect plane color equivalent border in visible light colors visually-perceptible space;

(3-3) saturation expansion ratio BI _lcharacterization regulation and control calculate, and comprising:

(3-3-1) saturation expansion ratio regulation and control coefficient B I is set _kx, number range 0.00-1,

BI _LY＝BI _L×BI _Kx

Wherein, BI _kxallow to arrange and be multiplely respectively used to specified requirements, BI _lYfor regulating and controlling rear saturation expansion ratio,

(3-3-2) the interval border H in pairs of form and aspect plane is set _dxand H _gx, number range 0 °-359 °, H _dxand H _gxallow to arrange and be multipairly respectively used to specified requirements,

Color h>=H _dxwith h≤H _gx, BI _lY=BI _l× BI _k2

All the other colors, BI _lY=BI _l× BI _k1

Inside border, form and aspect plane transition region arranges number range 0-20,

(3-3-3) saturation proportion threshold value C is set _gx, number range 0.00-1, C _gxallow to arrange and be multiplely respectively used to specified requirements,

C _gxbe worth following color, BI _lY=BI _l× BI _k2

C _gxbe worth above color, BI _lY=BI _l× BI _k1

C _gxbe worth high-end side transition region and number range 0.00-0.2 be set,

(3-4) calculating pixel color saturation C _lc after expansion _lN:

C _LN＝C _L×BI _LY，

As C _lNbe greater than C _gLthen calculate it to map:

C _LN＝C _gL+(C _LN-C _gL)/(C _maxLd-C _gL)×(C _maxL1-C _gL)；

(4) by Color image pixel brightness L, hue angle h and after step (3) expansion the saturation C that obtains _lNnumerical computations is specification R, G and B value.

According to method of the present invention, step (1) is for obtaining color digital image pixel color R, L, C and h numerical value of G and B numerical value in CIELAB space, wherein, h is hue angle, and L is brightness, C is saturation, can be realized by the existing known method in this area, preferably, according to specific embodiment of the invention scheme, first perform the step of invocation facility visually-perceptible color space form and aspect plane color boundaries computing module, obtain 3 × 3 necessary matrix coefficients.

According to of the present invention, the system that color digital image carries out the conversion of visually-perceptible high-fidelity is comprised:

(1) the colour vision aware space form and aspect plane color boundaries computing module of the equipment of display color digital picture, comprising:

(1-1) the red, green and blue tristimulus values of device color spaces is transformed to CIELAB space L, C and h value computing unit,

(1-2) equipment colour vision aware space form and aspect plane color edge extraction unit,

Enter corresponding reference colours phase face with the form and aspect h value merger equipment color that rounds up, enter corresponding bright sequence with the merger that rounds up of L value, extract the color maximum saturation angle value C of each brightness sequence of form and aspect plane _maxL1, calculate baseline values as the color boundaries of this form and aspect plane,

(1-3) form and aspect plane color boundaries C _maxL1smooth unit,

Select maximum saturation angle value C in form and aspect plane _maxh1the brightness L had _cmaxh1to minimum brightness L=0 brightness sequence interval corresponding to color boundaries C _maxL1, calculate smooth boundary with standard linear interpolation algorithm, make up C _maxL1non-ly smoothly successively decrease or fill up disappearance.The color boundaries calculated and by brightness L _cmaxh1the interval corresponding color boundaries of brightness sequence to L=100, represents the application color boundaries C of this form and aspect plane _maxL1;

(2) visible light colors visually-perceptible space form and aspect plane color equivalent border C _maxLdcomputing module;

(3) color digital image pixel color pattern forward conversion and merger form and aspect plane and brightness sequence module, comprising:

(3-1) color digital image pixel color rgb value is converted to the computing unit of L, C and h value in CIELAB space, wherein, h is hue angle, and L is brightness, C is saturation,

(3-2) pixel color form and aspect plane and brightness sequence Merging unit,

Be 360 reference colours phase face by color of image spatial division, corresponding reference colours phase face is entered with the merger that rounds up of form and aspect h value, brightness L scope in form and aspect plane is divided into 101 consensus sequences, enters corresponding bright sequence with the lightness l value merger that rounds up;

(4) Color image pixel intensity value expansion module, comprising:

(4-1) pixel color saturation expansion ratio BI _lcomputing unit:

BI _L＝C _maxLd/C _maxL1

Wherein, C _maxLdfor pixel place brightness sequence is in the borderline intensity value of visible ray form and aspect plane color equivalent, C _maxL1for the intensity value of pixel place brightness sequence in equipment form and aspect plane color boundaries,

(4-2) saturation expansion ratio BI _lcharacterization regulation and control computing unit, comprising:

(4-2-1) saturation expansion ratio regulation and control coefficient B I is set _kx, number range 0.00-1,

BI _LY＝BI _L×BI _Kx

Wherein, BI _kxallow to arrange multiple, be respectively used to specified requirements, BI _lYfor regulating and controlling rear saturation expansion ratio,

(4-2-2) the interval border H in pairs of form and aspect plane is set _dxand H _gx, number range 0 °-359 °, H _dxand H _gxallow to arrange and be multipairly respectively used to specified requirements:

Color h>=H _dxwith h≤H _gx, BI _lY=BI _l× BI _k2

All the other colors, BI _lY=BI _l× BI _k1

Inside border, form and aspect plane transition region arranges number range 0-20,

(4-2-3) saturation proportion threshold value C is set _gx, number range 0.00-1, C _gxallow to arrange and be multiplely respectively used to specified requirements:

C _gxbe worth following color, BI _lY=BI _l× BI _k2

C _gxbe worth above color, BI _lY=BI _l× BI _k1

C _gxbe worth high-end side transition region and number range 0.00-0.2 be set,

(4-3) saturation maps flex point C _gLcomputing unit:

C _gL＝C _maxL1×X _S1

Set scale coefficient X _s1number range 0.65-0.95,

(4-4) pixel color saturation C _lexpand to C _lNcomputing unit:

C _LN＝C _L×BI _LY，

Judge, if C _lNbe greater than C _gLthen calculate mapping:

C _LN＝C _gL+(C _LN-C _gL)/(C _maxLd-C _gL)×(C _maxL1-C _gL)；

(5) Color image pixel pattern transformation by reciprocal direction and normalizing block:

Described calculating comprises L, h of Color image pixel and expands the saturation C obtained through module (4) _lNnumerical computations is specification R, G and B value.

According to the preferred embodiments of the invention, described system also comprises visible light colors visually-perceptible space form and aspect plane color maximum saturation computing module.

As the preferred technical solution of the present invention, equipment visually-perceptible color space form and aspect plane color boundaries database first completes via the equipment visually-perceptible color space form and aspect plane color boundaries computing module computing in system of the present invention, and calculating comprises:

(1-1) the red, green and blue tristimulus values of device color spaces is transformed to the calculating of CIELAB space L, C and h value, is transformed to CIELAB space L, C and h value computing unit performs by the red, green and blue tristimulus values of device color spaces:

The white field of use equipment nominal and red, green and blue three primary colors relevant parameter, the canonical algorithm that application CIE recommends, by whole colors that the red, green and blue three primary colors of equipment synthesize, is converted to CIEXYZ tristimulus values and CIELAB space L, C and h value, comprising:

Application nominal sRGB space RGB three primary colors chromaticity parameter and the white field parameters of D65 calculate the brightness value of RGB three primary colors maximum saturation:

Y _r，max＝0.2126 Y _g，max＝0.7152 Y _b，max＝0.0722

Application is above calculates 3 × 3 matrix coefficients:

$\left[\begin{array}{ccc}0.4124& 0.3576& 0.1805\\ 0.2126& 0.7152& 0.0722\\ 0.0193& 0.1192& 0.9505\end{array}\right]$

Non-standard equipment need calculate CIEXYZ tristimulus values when white field and red, green and blue three primary colors maximum saturation:

Use standard spectral photometric instrument, the conveniently white field tristimulus values X of criterion equipment _w', Y _w' and Z _w', calculate white field normalization coefficient K ₁:

K ₁＝100/Y _w’

The CIEXYZ tristimulus values of the white field of computing equipment:

X _w＝X _w’×K ₁ Y _w＝Y _w’×K ₁ Z _w＝Z _w’×K ₁

Use standard spectral photometric instrument, the tristimulus values conveniently under specification difference measuring equipment red, green and blue three primary colors maximum saturation condition, X _r', Y _r' and Z _r', X _g', Y _g' and Z _g', X _b', Y _b' and Z _b'.Calculate trichromatic CIEXYZ tristimulus values respectively:

X _r，max＝X _r’×K ₁，Y _r，max＝Y _r’×K ₁，Z _r，max＝Z _r’×K ₁

X _g，max＝X _g’×K ₁，Y _g，max＝Y _g’×K ₁，Z _g，max＝Z _g’×K ₁

X _b，max＝X _b’×K ₁，Y _b，max＝Y _b’×K ₁，Z _b，max＝Z _b’×K ₁

By the three primary colors CIEXYZ tristimulus values calculated above, substitute 3 × 3 matrix coefficients in the above standard method, substitute the above equipment nominal white field CIEXYZ tristimulus values with the white field CIEXYZ tristimulus values calculated, calculate CIELAB space L, C and h numerical value.

(1-2) equipment visually-perceptible color space form and aspect plane color boundaries calculates, and is performed by equipment colour vision aware space form and aspect plane color edge extraction unit:

With 0-359 integer representation reference colours phase face, corresponding reference colours phase face is entered with the form and aspect h value merger equipment color that rounds up, and with 0-100 integer representation Benchmark brightness sequence, enter corresponding bright sequence with the merger that rounds up of L value, extract color maximum saturation angle value C in each brightness sequence of form and aspect plane _maxL1, calculate basis as the color boundaries of this form and aspect plane;

(1-3) form and aspect plane color boundaries smoothing computation, by form and aspect plane color boundaries C _maxL1smooth unit performs:

Extract maximum saturation angle value C in form and aspect plane _maxh1the brightness L had _cmaxh1to minimum brightness L=0 brightness sequence interval corresponding to color boundaries, with standard linear interpolation algorithm calculate smooth boundary, make up the maximum saturation C of former brightness sequence _maxL1non-ly smoothly successively decrease or fill up disappearance.The color boundaries C calculated _maxL1and by brightness L _cmaxh1the interval corresponding color boundaries C of brightness sequence to L=100 _maxL1, represent the application color boundaries of this form and aspect plane.

Above result of calculation is stored as database, and data sort with first sequence form and aspect plane order brightness sequence, totally 36360 row.

According to specific embodiment of the invention scheme, perform step (2) afterwards with step (1): the visually-perceptible color space form and aspect plane color equivalent data boundary storehouse of calling visible ray.

As another optimal technical scheme of the present invention, form and aspect plane color equivalent data boundary storehouse, visible light colors visually-perceptible space first completes via the visible light colors visually-perceptible space form and aspect plane color maximum saturation computing module in system of the present invention and visible light colors visually-perceptible space form and aspect plane color equivalent feature modeling module arithmetic, and calculating comprises:

(2-1) visible light colors visually-perceptible space form and aspect plane color maximum saturation calculates, and is performed by visible light colors visually-perceptible space form and aspect plane color maximum saturation computing module:

(2-1-1) form and aspect plane 38 °-317 ° calculating, are performed by form and aspect plane 38 ° of-317 ° of computing units:

With x, y and z numerical value of CIE 1931XYZ standard colorimetric observer spectral tristimulus value medium wavelength 380nm to 780nm interval 5nm, and the white field CIEXYZ tristimulus values of computing equipment color space application, the method of recommending with CIE calculates L, C and h numerical value, and to round up merger form and aspect plane with h value, take L and the C numerical value of form and aspect plane in 38 ° to 317 ° form and aspect intervals, linear interpolation calculates L and the C value of blank form and aspect plane wherein, the maximum saturation C using L and C value as the corresponding form and aspect plane in visible light colors visually-perceptible space _maxh2and brightness L _cmach2.

(2-1-2) form and aspect plane 0 °-37 ° and 318 °-359 ° calculating, are performed by form and aspect plane 0 °-37 ° and 318 ° of-359 ° of computing units:

With the white field CIEXYZ tristimulus values that CIERGB color space red, green and blue three primary colors canonical parameter and computing equipment color space are applied, calculate L, C and h parameter of whole red, green and blue three primary colors synthesis color, comprising:

3 × 3 matrix coefficients are calculated with same procedure in nominal CIERGB space RGB three primary colors chromaticity parameter and D65 white field parameters application above-mentioned steps (1):

X _r，max＝0.4108 Y _r，max＝0.1481 Z _r，max＝0

X _g，max＝0.3210 Y _g，max＝0.8401 Z _g，max＝0.0105

X _b，max＝0.2185 Y _b，max＝0.0118 Z _b，max＝1.0783

In the form and aspect plane of merger, select 0 ° to 37 ° and 318 ° to 359 ° form and aspect planes, and extract wherein maximum saturation C _maxh2and brightness L _cmach2numerical value.

(2-2) visible light colors visually-perceptible space form and aspect plane color equivalent feature modeling, by visible light colors visually-perceptible space form and aspect plane color equivalent border C _maxLdcomputing module performs:

(2-2-1) visible light colors visually-perceptible space and equipment colour vision aware space form and aspect plane maximum saturation ratio and optimizing calculates, and is performed by visible light colors visually-perceptible space and equipment colour vision aware space form and aspect plane maximum saturation ratio and optimization calculation unit:

Select 0 ° to 359 ° form and aspect plane respectively, calculate visible light colors space C _maxh2with device color spaces C _maxh1ratio value B _maxh:

B _maxh＝C _maxh2/C _maxh1

Set scale coefficient F _x1with equivalent coefficient F _x2, wherein, F _x1number range 2.50-6.00, F _x2number range 1.50-2.50, calculates B _maxhstandardization equivalents ratio B _maxd:

B _maxhvalue is greater than F _x1form and aspect plane standardization calculate:

B _maxd=(B _maxh-F _x1interval maximum scale value-the F of)/(ratio _x1) × 0.1+F _x2

B _maxhvalue is less than or equal to F _x1be greater than (F _x1-1) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-1))/(interval maximum scale value-(F of ratio _x1-1)) × 0.05+ (F _x2-0.05)

B _maxhvalue is less than or equal to (F _x1-1) (F is greater than _x1-1.5) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-1.5))/(interval maximum scale value-(F of ratio _x1-1.5)) × 0.05+ (F _x2-0.1)

B _maxhvalue is less than or equal to (F _x1-1.5) (F is greater than _x1-2) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-2))/(interval maximum scale value-(F of ratio _x1-2)) × 0.1+ (F _x2-0.2)

B _maxhvalue is less than or equal to (F _x1-2) (F is greater than _x1-2.5) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-2.5))/(interval maximum scale value-(F of ratio _x1-2.5)) × 0.05+ (F _x2-0.25)

B _maxhvalue equals (F _x1-2.5) and following form and aspect plane standardization calculate:

B _maxd=B _maxhinterval maximum scale value × 0.05+ (the F of/ratio _x2-0.3)

(2-2-2) visible light colors space form and aspect plane maximum saturation equivalent and color boundaries calculate, by visible light colors space form and aspect plane maximum saturation equivalent C _maxhdand color equivalent border C _maxLdcomputing unit performs:

Form and aspect plane maximum saturation equivalent C _maxhdcalculate:

C _maxhd＝C _maxh1×B _maxd

Form and aspect plane color equivalent feature modeling:

Abscissa be saturation C, ordinate is the cartesian coordinate plane of brightness L, with C _maxh2and L _cmaxh2value, punctuate D _maxh2, at D _maxh2c is indicated to L=100 point line _maxhd, the brightness sequence value that its ordinate value rounds up is designated as L _cmaxhd, its coordinate points is designated as D _maxhd;

Indicate the equipment color boundaries of identical form and aspect plane at coordinate plane, then indicate D _maxhdto L=0 point line, under the prerequisite that the maximum saturation angle value calculating corresponding bright sequence in its brightness section is smoothly successively decreased, contain the intensity value C needed for equipment color boundaries _maxhd, this partial value and D _maxhdintensity value C to L=100 point line _maxhd, form the equivalent border of visible ray form and aspect plane color.Above result of calculation is stored as database, and data sort with first sequence form and aspect plane order brightness sequence, totally 36360 row.

According to the specific embodiment of the present invention, the red, green and blue tristimulus values that step (3) is color digital image is converted to CIELAB space L, C and h value and merger enters corresponding form and aspect plane and brightness sequence.Call color digital image pixel color pattern forward conversion in system of the present invention and merger form and aspect plane and brightness sequence module to calculate:

(3-1) color digital image pixel color rgb value is converted to the calculating of L, C and h value in CIELAB space, the computing unit being converted to L, C and h value in CIELAB space by color digital image pixel color rgb value performs:

The white field using the equipment nominal of display image or image itself to embed and red, green and blue three primary colors relevant parameter, the canonical algorithm that application CIE recommends, by the color that the red, green and blue three primary colors of image pixel synthesize, be converted to CIEXYZ tristimulus values and CIELAB space L, C and h value, comprising:

Application nominal sRGB space RGB three primary colors chromaticity and the white field parameters of D65, calculate the brightness value of RGB three primary colors maximum saturation:

Y _r，max＝0.2126 Y _g，max＝0.7152 Y _b，max＝0.0722

The above value of application calculates 3 × 3 matrix coefficients:

$\left[\begin{array}{ccc}0.4124& 0.3576& 0.1805\\ 0.2126& 0.7152& 0.0722\\ 0.0193& 0.1192& 0.9505\end{array}\right]$

Non-standard equipment shows the CIEXYZ tristimulus values of the image palpus white field of computing equipment and red, green and blue three primary colors maximum saturation:

Use standard spectral photometric instrument, the conveniently white field tristimulus values X of criterion equipment _w', Y _w' and Z _w', calculate white field normalization coefficient K ₁:

K ₁＝100/Y _w’

The CIEXYZ tristimulus values of the white field of computing equipment:

X _w＝X _w’×K ₁，Y _w＝Y _w’×K ₁，Z _w＝Z _w’×K ₁

Use standard spectral photometric instrument, the tristimulus values conveniently under specification difference measuring equipment red, green and blue three primary colors maximum saturation condition, X _r', Y _r' and Z _r', X _g', Y _g' and Z _g', X _b', Y _b' and Z _b' calculate trichromatic CIEXYZ tristimulus values respectively:

X _r，max＝X _r’×K ₁，Y _r，max＝Y _r’×K ₁，Z _r，max＝Z _r’×K ₁

X _g，max＝X _g’×K ₁，Y _g，max＝Y _g’×K ₁，Z _g，max＝Z _g’×K ₁

X _b，max＝X _b’×K ₁，Y _b，max＝Y _b’×K ₁，Z _b，max＝Z _b’×K ₁

By the three primary colors CIEXYZ tristimulus values calculated above, substitute 3 × 3 matrix coefficients in the above standard method, substitute the above equipment nominal white field CIEXYZ tristimulus values with the white field CIEXYZ tristimulus values calculated, calculate CIELAB space L, C and h numerical value.

(3-2) pixel color form and aspect plane and brightness sequence merged calculate, is performed by pixel color form and aspect plane and brightness sequence Merging unit:

Be 0-359 totally 360 reference colours phase face by color of image spatial division, corresponding reference colours phase face is entered with the merger that rounds up of Color image pixel form and aspect h value, brightness L scope in form and aspect plane is divided into 0-100 totally 101 consensus sequences, corresponding bright sequence is entered with the merger that rounds up of colour brightness L value, make pixel color parameter available integer form and aspect h, integer brightness L and the saturation C containing four decimals represents, reaches one of design conditions of saturation expansion.

According to the specific embodiment of the present invention, step (4) is the expansion of computed image pixel color saturation.Call the Color image pixel intensity value expansion module in system of the present invention, calculating comprises:

(4-1) calculating pixel color saturation maps flex point C _gL, map flex point C by saturation _gLcomputing unit performs:

C _gL＝C _maxL1*X _S1

C _maxL1for the maximum saturation angle value called at equipment visually-perceptible color space form and aspect bitplane data library searching with pixel color phase face and brightness sequence integer value, X _s1for the flex point function arranged as required, number range 0.65-0.95, is typically 0.8-0.9;

(4-2) calculating pixel color saturation expansion ratio BI _l, expand ratio BI by pixel color saturation _lcomputing unit performs:

BI _L＝C _maxLd/C _maxL1

C _maxLdfor the equivalent intensity value called at photopic vision perceptual color space form and aspect plane color equivalent data boundary library searching with pixel color phase face and brightness sequence integer value;

Allow the multiple saturation expansion ratio regulator module called in system of the present invention:

(4-2-1) submodule of saturation expansion ratio regulation and control is set:

Described calculating comprise arrange multiple saturation expansion ratio regulation and control coefficient B I _kx, number range 0.00-1, with BI _lY=BI _kx× BI _las the saturation expansion ratio of pixel practical application, typical case, character image BI _k2be typically 0.10-0.40, landscape image BI _k1be typically 0.40-0.90;

(4-2-2) submodule of form and aspect plane interval border is set:

Described calculating comprises arranging how group form and aspect plane is interval, form and aspect interval border H _dxand H _gx, number range 0 °-359 °, uses the saturation different from outside interval to expand ratio BI to color in bulletin colour mutually interval _lY, the mutually interval H of character image typical color _d1=340 ° and H _g1=100 °, in this form and aspect interval, BI _lY=BI _k2× BI _l; Beyond this form and aspect interval, BI _lY=BI _k1× BI _l.Inside form and aspect interval border, establish intermediate color separately, control bulletin colour mutually interval inside and outside saturation expansion ratio smoothly changes, transition region number range 0-20;

(4-2-3) submodule of saturation proportion threshold value is set:

Described calculating comprises and arranges saturation ratio value as threshold value C _gx, number range 0.00-1, threshold value uses the saturation ratio boundary of different saturation expansion ratio as color in same brightness sequence, and typical case, character image arranges C _gxbe typically 0.50-0.75, the following color of threshold value, BI _lY=BI _k2× BI _l, the above color of threshold value, BI _lY=BI _k1× BI _l.Transition region is established in the above side of threshold value, and regulation and control saturation expansion ratio smoothly changes, transition region number range 0.00-0.2;

(4-3) calculating pixel color saturation C _lexpansion, by pixel color saturation C _lexpand to C _lNcomputing unit performs:

C _LN＝C _L*BI _LY，

BI _lYbe subject to the regulation and control that above-mentioned three species saturation expansion ratio regulation and control are arranged, result of calculation C _lNif be greater than C _gLthen calculate mapping:

C _LN＝C _gL+(C _LN-C _gL)/(C _maxLd-C _gL)*(C _maxL1-C _gL)

According to the specific embodiment of the present invention, step (5) is by Color image pixel L, h and saturation C _lNnumerical computations is specification R, G and B value.According to the preferred technical solution of the present invention, call the Color image pixel pattern transformation by reciprocal direction in system of the present invention and normalizing block, calculating comprises:

The standard method using CIE to recommend, calculates with Color image pixel and unaltered brightness L, hue angle h value and the C that obtains after expanding as calculated _lNvalue is calculated as the red, green and blue tristimulus values of equipment.This algorithm is the inverse operation of above step (3), needed for pixel color CIELAB calculation of parameter CIEXYZ tristimulus values, white field CIEXYZ tristimulus values calculates identical with forward, calculates 3 × 3 matrix coefficients needed for rgb value to be inverted acquisition by above step (3) matrix 3 × 3 used coefficient by pixel color CIEXYZ tristimulus values:

$\left[\begin{array}{ccc}3.2406& -0.9689& 0.0557\\ -1.5372& 1.8758& -0.2040\\ -0.4986& 0.0415& 1.0570\end{array}\right]$

Respectively R, G and B value calculated is rounded, and 255 are turned to the numerical value specification being greater than 255,0 is turned to the numerical value specification being less than 0.

Typical case synthesizes the digital picture of color by red, green and blue three primary colors, for landscape image, after FECr algorithm according to the present invention adjusts the visually-perceptible saturation parameters of each pixel color, with image initial saturation numeric ratio comparatively, after can seeing the adjustment of FECr algorithm, color saturation value increasing degree is on average about 52%, and the pixel intensity of image about 50% adds 70%, and the pixel of 30% increases 70-30%, the pixel of 10% increases 30-10%, and the pixel of 10% increases 10-0%.Relation between the ratio of the form and aspect plane brightness sequence maximum saturation angle value of its merger relative of the pixel color intensity value before and after adjustment, shows the non-linear of the actual increment of saturation.

According to FECr algorithm of the present invention, under the condition that the device color spaces border of display image does not expand, in computed image, the more sensitive color of vision makes it to increase relatively many visible light colors vision perception characteristics, calculate relatively insensitive color increase less or remain unchanged, this non-linear Enhancement Method can make viewing image obtain relatively significantly close to the effect of watching actual scenery in visible light colors space.

Accompanying drawing explanation

The equal-energy spectrum track that Fig. 1 calculates with CIE1931XYZ system spectrum tristimulus values and indicates at CIE xyY space xy coordinate plane, abscissa x, ordinate y.

Fig. 2-1 flow chart color digital image being carried out to the method for visually-perceptible high-fidelity conversion according to a particular embodiment of the invention, describes equipment colour vision aware space form and aspect plane color boundaries calculation process;

Fig. 2-2 flow chart color digital image being carried out to the method for visually-perceptible high-fidelity conversion according to a particular embodiment of the invention, describes visible light colors visually-perceptible space form and aspect plane color equivalent feature modeling flow process;

Fig. 2-3 flow chart color digital image being carried out to the method for visually-perceptible high-fidelity conversion according to a particular embodiment of the invention, describes color digital image pixel color high-fidelity visually-perceptible transformation calculations flow process.

The whole merger color coordinates of red circle display non-standard equipment colour vision aware space example form and aspect plane in Fig. 3 figure, middle part gray line represents merger brightness sequence algorithm, and bottom gray line represents with linear interpolation correction corresponding bright sequence maximum saturation C _maxL1non-ly smoothly successively decrease and make up disappearance result of calculation, abscissa saturation C, ordinate brightness L.

The relevant colors border of Fig. 4 Show Color visually-perceptible space form and aspect plane, abscissa saturation C, ordinate brightness L, exemplify h=110 ° of form and aspect plane, wherein, Bluepoint indication equipment maximum saturation C _maxh1, blue line represents color boundaries C _maxL1, black circle red expression visible light colors maximum saturation equivalent C _maxhd, black dotted line represents equivalent color boundaries C _maxLd, red expression visible light colors maximum saturation C _maxh2, its signal border of red line table.

Fig. 5 shows calculating pixel colour vision perception saturation expansion algorithm, C in figure _lpoint represents pixel color coordinate, C _gLpoint represents that saturation maps flex point, and red line represents the brightness sequence of color merger, and all the other are identical with Fig. 4.

Fig. 6 and Fig. 7 display is through method of the present invention image before and after treatment, and the right of coloured image is former figure, and the left side is that FECr algorithm calculates the rear image of saturation C expansion.

Fig. 8-1 uses the canonical system flow process of FECr algorithm computer program.

Fig. 8-2 uses the television set canonical system flow process of FECr algorithm IP.

Fig. 8-3 uses the television set canonical system flow process of FECr algorithm ASIC.

Fig. 8-4 uses the electronic equipment canonical system flow process of FECr algorithm ASIC.

Embodiment

Embodiment 1

Implement color digital image pixel color visually-perceptible high-fidelity shift process of the present invention.

(1) computing equipment colour vision aware space form and aspect plane color boundaries database.

Database completes via the equipment colour vision aware space form and aspect plane color boundaries computing module computing in system of the present invention, and calculating comprises:

(1-1) the red, green and blue tristimulus values of device color spaces is transformed to the calculating of CIELAB space L, C and h value, is transformed to CIELAB space L, C and h value computing unit by device color spaces red, green and blue tristimulus values and performs:

The electronic equipment with image display function is typically sRGB color space and the white field of D65, and sRGB space RGB three primary colors chromaticity is consulted:

x _r，max＝0.64 y _r，max＝0.33，x _g，max＝0.30 y _g，max＝0.60，x _b，max＝0.15 y _b，max＝0.06

D65 white field CIEXYZ tristimulus values is consulted:

X _w＝0.950456 Y _w＝1 Z _w＝1.089058

3 × 3 matrix coefficients needed for above calculation of parameter colour switching:

Utilize the trichromatic rgb value in the white field of equipment and CIEXYZ tristimulus values and positive-going transition formula:

$\left[\begin{array}{c}0.9505\\ 1.0000\\ 1.0891\end{array}\right]=\left[\begin{array}{ccc}{X}_{r,\max }& X_{g,\max }& X_{b,\max }\\ Y_{r,\max }& Y_{g,\max }& Y_{b,\max }\\ Z_{r,\max }& Z_{g,\max }& Z_{b,\max }\end{array}\right]\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]$

3 × 3 matrix coefficients are expressed as the product form of three primary colors chromatic value and brightness value:

$\left[\begin{array}{c}0.9505\\ 1.0000\\ 1.0891\end{array}\right]=\left[\begin{array}{ccc}(x_{r,\max }/y_{r,\max })Y_{r,\max }& (x_{g,\max }/y_{g,\max })Y_{g,\max }& (x_{b,\max }/y_{b,\max })Y_{b,\max }\\ Y_{r,\max }& Y_{g,\max }& Y_{b,\max }\\ (z_{r,\max }/y_{r,\max })Y_{r,\max }& (z_{g,\max }/y_{g,\max })Y_{g,\max }& (z_{b,\max }/y_{b,\max })Y_{b,\max }\end{array}\right]\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]$

The brightness value of RGB three primary colors maximum saturation is calculated by above equation:

Y _r，max＝0.2126 Y _g，max＝0.7152 Y _b，max＝0.0722

The above value of application calculates matrix 3 × 3 coefficient:

$\left[\begin{array}{ccc}0.4124& 0.3576& 0.1805\\ 0.2126& 0.7152& 0.0722\\ 0.0193& 0.1192& 0.9505\end{array}\right]$

Apply the conversion of above matrix coefficient computing equipment color rgb value to CIEXYZ space X, Y and Z value, then apply D65 white field tristimulus values calculating color XYZ value to CIELAB space L, C and h value transform.

Exemplary apparatus often plants 8 synthesis colors by red, green and blue three primary colors, and namely 2 ^{3 × 8}totally 16777216 kinds of color scalars, successively by having calculated conversion above.

Non-standard equipment calculates CIEXYZ tristimulus values when white field and red, green and blue three primary colors maximum saturation:

Use standard spectral photometric instrument, the conveniently white field tristimulus values X of criterion equipment _w', Y _w' and Z _w', calculate white field normalization coefficient K ₁:

K ₁＝100/Y _w’

The CIEXYZ tristimulus values of the white field of computing equipment:

X _w＝X _w’×K ₁，Y _w＝Y _w’×K ₁，Z _w＝Z _w’×K ₁

Use standard spectral photometric instrument, the tristimulus values conveniently under specification difference measuring equipment red, green and blue three primary colors maximum saturation condition, X _r', Y _r' and Z _r', X _g', Y _g' and Z _g', X _b', Y _b' and Z _b', then calculate trichromatic CIEXYZ tristimulus values respectively:

X _r，max＝X _r’×K ₁，Y _r，max＝Y _r’×K ₁，Z _r，max＝Z _r’×K ₁

X _g，max＝X _g’×K ₁，Y _g，max＝Y _g’×K ₁，Z _g，max＝Z _g’×K ₁

X _b，max＝X _b’×K ₁，Y _b，max＝Y _b’×K ₁，Z _b，max＝Z _b’×K ₁

By CIEXYZ tristimulus values during the three primary colors maximum saturation calculated above, substitute 3 × 3 matrix coefficients in the above standard method, the above equipment nominal white field CIEXYZ tristimulus values is substituted with the white field CIEXYZ tristimulus values calculated, applying the above standard method, is CIELAB space L, C and h numerical value by R, G and B numerical transformation of totally 16777216 kinds of colors successively.

(1-2) calculating of equipment colour vision aware space form and aspect plane color boundaries, is performed by equipment colour vision aware space form and aspect plane color edge extraction unit.

With 0-359 integer representation reference colours phase face, enter corresponding reference colours phase face with the form and aspect h value merger equipment color that rounds up, with 0-100 integer representation Benchmark brightness sequence, enter corresponding bright sequence with the L value merger color that rounds up.Extract maximum saturation angle value C in each brightness sequence of form and aspect plane _maxL1, calculate basis as the color boundaries of this form and aspect plane.

(1-3) form and aspect plane color boundaries smoothing computation, by form and aspect plane color boundaries C _maxL1smooth unit performs:

Extract maximum saturation angle value C in form and aspect plane _maxh1the brightness L had _cmaxh1to minimum brightness L=0 brightness sequence interval corresponding to color boundaries, with standard linear interpolation algorithm calculate smooth boundary, repair the maximum saturation C of former brightness sequence _maxL1non-ly smoothly successively decrease or fill up disappearance.This part colours border C calculated _maxL1together with by brightness L _cmaxh1the interval corresponding color boundaries C of brightness sequence to L=100 _maxL1, represent the final application color boundaries of this form and aspect plane.

Alleged level and smooth in above algorithm, i.e. colour brightness sequence arranges from high to low, its saturation C _maxL1be less than above sequence and be greater than following all sequences.Saturation is less than calculated value and then uses calculated value, is greater than calculated value then constant.

Above result of calculation is stored as database.Data sort according to first sequence form and aspect plane h order brightness sequence L, totally 36360 row.Above step (1) calculation process is as shown in Fig. 2-1.

(2) form and aspect plane color equivalent data boundary storehouse, visible light colors visually-perceptible space is calculated.

Form and aspect plane color equivalent data boundary storehouse, visible light colors visually-perceptible space completes via the visible light colors visually-perceptible space form and aspect plane color maximum saturation computing module in system of the present invention and visible light colors visually-perceptible space form and aspect plane color equivalent feature modeling module arithmetic, and calculating comprises:

(2-1) visible light colors visually-perceptible space form and aspect plane color maximum saturation calculates,

(2-1-1) form and aspect plane 38 °-317 ° calculating, are performed by form and aspect plane 38 ° of-317 ° of computing units:

With x, y and z numerical value of CIE 1931XYZ standard colorimetric observer spectral tristimulus value medium wavelength 380nm to 780nm interval 5nm, and D65 white field CIEXYZ tristimulus values, the method of recommending with CIE calculates CIELAB space L, C and h numerical value, and to round up merger form and aspect plane with h value, take L and the C numerical value of form and aspect plane in 38 ° to 317 ° form and aspect intervals, and L and the C value of linear interpolation calculation blank form and aspect plane wherein, the maximum saturation C using L and C value as the corresponding form and aspect plane in visible light colors visually-perceptible space _maxh2and brightness L _cmach2.

(2-1-2) form and aspect plane 0 °-37 ° and 318 °-359 ° calculating, are performed by form and aspect plane 0 °-37 ° and 318 ° of-359 ° of computing units:

Application CIERGB space RGB three primary colors chromaticity parameter:

x _r，max＝0.735 Y _r，max＝0.265，x _g，max＝0.274 Y _g，max＝0.717，x _b，max＝0.167 Y _b，max＝0.009

And the white field parameters of D65, calculate 3 × 3 matrix coefficients with same procedure in step (1):

X _r，max＝0.4108 Y _r，max＝0.1481 Z _r，max＝0

X _g，max＝0.3210 Y _g，max＝0.8401 Z _g，max＝0.0105

X _b，max＝0.2185 Y _b，max＝0.0118 Z _b，max＝1.0783

With above-mentioned matrix coefficient and D65 white field CIEXYZ tristimulus values, calculate L, C and h parameter of whole colors of CIERGB space red, green and blue three primary colors synthesis, in the form and aspect plane of merger, select 0 ° to 37 ° and 318 ° to 359 ° form and aspect planes, and extract wherein maximum saturation C _maxh2and brightness L _cmach2numerical value.

(2-2) visible light colors visually-perceptible space form and aspect plane color equivalent feature modeling, by visible light colors visually-perceptible space form and aspect plane color equivalent border C _maxLdcomputing module performs:

(2-2-1) visible light colors visually-perceptible space and equipment colour vision aware space form and aspect plane maximum saturation ratio and optimizing calculates, and is performed by visible light colors visually-perceptible space and equipment colour vision aware space form and aspect plane maximum saturation ratio and optimization calculation unit:

Select 0 ° to 359 ° form and aspect plane, calculate visible light colors space C respectively _maxh2with device color spaces C _maxh1ratio value B _maxh:

B _maxh＝C _maxh2/C _maxh1

Check and find B _maxhmaximum close to 5, the unsuitable directly application percentage value B of application discovering device sRGB color space _maxhextension color saturation.

Set scale coefficient F _x1with equivalent coefficient F _x2, wherein F _x1numerical value is 4.5, F _x2numerical value is 1.9, calculates B _maxhstandardization equivalent value B _maxd:

B _maxhvalue is greater than F _x1form and aspect plane standardization calculate:

B _maxd=(B _maxh-F _x1interval maximum scale value-the F of)/(ratio _x1) * 0.1+F _x2

B _maxhvalue is less than or equal to F _x1be greater than (F _x1-1) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-1))/(interval maximum scale value-(F of ratio _x1-1)) * 0.05+ (F _x2-0.05)

B _maxhvalue is less than or equal to (F _x1-1) (F is greater than _x1-1.5) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-1.5))/(interval maximum scale value-(F of ratio _x1-1.5)) * 0.05+ (F _x2-0.1)

B _maxhvalue is less than or equal to (F _x1-1.5) (F is greater than _x1-2) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-2))/(interval maximum scale value-(F of ratio _x1-2)) * 0.1+ (F _x2-0.2)

B _maxhvalue is less than or equal to (F _x1-2) (F is greater than _x1-2.5) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-2.5))/(interval maximum scale value-(F of ratio _x1-2.5)) * 0.05+ (F _x2-0.25)

B _maxhvalue equals (F _x1-2.5) and following form and aspect plane standardization calculate:

B _maxd=B _maxh/ ratio interval maximum scale value * 0.05+ (F _x2-0.3)

(2-2-2) visible light colors visually-perceptible space form and aspect plane maximum saturation equivalent and color equivalent feature modeling, by visible light colors visually-perceptible space form and aspect plane maximum saturation equivalent C _maxhdand color equivalent border C _maxLdcomputing unit performs:

Form and aspect plane maximum saturation equivalent C _maxhdcalculate:

C _maxhd＝C _maxh1×B _maxd

Form and aspect plane color equivalent feature modeling:

In the cartesian coordinate plane of abscissa to be saturation C and ordinate be brightness L, with C _maxh2and L _cmaxh2value punctuate D _maxh2, at D _maxh2c is indicated to L=100 point line _maxhd, the brightness sequence value that its ordinate value rounds up is designated as L _cmaxhd, its coordinate points is designated as D _maxhd.

Indicate the equipment color boundaries of identical form and aspect plane at this coordinate plane, then indicate D _maxhdto L=0 point line, under the prerequisite that the maximum saturation angle value calculating corresponding bright sequence in its brightness section is smoothly successively decreased, contain the intensity value C needed for equipment color boundaries _maxLd, this partial value and D _maxhdintensity value C to L=100 point line _maxLd, form the equivalent border of visible ray form and aspect plane color.

The algorithm of the saturation above needed for alleged containing equipment color boundaries, increases 2-3% with the maximum saturation angle value of flex point brightness sequence in equipment color boundaries.

Above result of calculation is stored as database, with above equipment color data library format and sort identical.

(2-3) visible light colors calculates when quantity space and device color spaces form and aspect plane maximum saturation ratio:

Form and aspect plane maximum saturation C is retrieved respectively from above two databases _maxh1and C _maxhdboth calculating ratio, building database, sorts with form and aspect plane h, data 360 row.Above step (2) calculation process is as shown in Fig. 2-2.

(3) the red, green and blue tristimulus values completing color digital image is converted to CIELAB space L, C and h value and merger enters corresponding form and aspect plane and brightness sequence, is performed by color digital image pixel color pattern forward conversion and merger form and aspect plane and brightness sequence module.

Calculating comprises:

(3-1) color digital image pixel color rgb value is converted to the calculating of L, C and h value in CIELAB space, and the computing unit being converted to L, C and h value in CIELAB space by color digital image pixel color rgb value performs:

The white field using the equipment nominal of display image or image itself to embed and red, green and blue three primary colors relevant parameter, the canonical algorithm that application CIE recommends, be CIEXYZ tristimulus values and CIELAB space L, C and h value by the color conversion that the red, green and blue three primary colors of image pixel represent, algorithm routine and relevant parameter identical with step (1).

Non-standard equipment shows CIEXYZ tristimulus values when image needs the white field of survey calculation equipment and red, green and blue three primary colors maximum saturation, algorithm routine and relevant parameter identical with step (1).

(3-2) pixel color form and aspect plane and brightness sequence merged calculate, is performed by pixel color form and aspect plane and brightness sequence Merging unit:

Be 0-359 totally 360 reference colours phase face by color of image spatial division, corresponding reference colours phase face is entered with the merger that rounds up of form and aspect h value, brightness L scope in form and aspect plane is divided into 0-100 totally 101 consensus sequences, corresponding bright sequence is entered with the lightness l value merger that rounds up, make pixel color parameter available integer form and aspect h, integer brightness L and the saturation C containing four decimals represents, creates one of design conditions of saturation expansion.

(4) calculating pixel color saturation expansion, is performed by Color image pixel intensity value expansion module.

Calculating comprises:

(4-1) calculating pixel color saturation maps flex point C _gL, map flex point C by saturation _gLcomputing unit performs:

C _gL＝C _maxL1*X _S1

Flex point function X is set _s1be 0.85;

(4-2) calculating pixel color saturation expansion ratio BI _l, expand ratio BI by pixel color saturation _lcomputing unit performs:

BI _L＝C _maxLd/C _maxL1

Call the multiple saturation expansion ratio regulator module in system of the present invention:

(4-2-1) saturation expansion ratio regulation and control coefficient is set:

Described calculating comprise arrange multiple saturation expansion ratio regulation and control coefficient B I _kx, number range 0.00-1, with BI _lY=BI _kx× BI _las the saturation expansion ratio of pixel practical application.

Typical case, BI _k1=0.75 is the image of main contents for scenery, BI _k2=0.15 is the image of main contents for personage.

(4-2-2) bulletin colour phase face interval border is set:

Described calculating comprises and arranges multipair bulletin colour phase face interval border H _dxand H _gx, number range 0 °-359 °.Typical case, character image arranges H _d1=340 ° and H _g1=100 °, hue angle h≤H _g1or h>=H _d1form and aspect plane color application BI _lY=BI _k2× BI _l, all the other color application BI _lY=BI _k1× BI _l.Arranging form and aspect interval border inner transition form and aspect interval numerical value is 10.

(4-2-3) saturation proportion threshold value is set:

Described calculating comprises and arranges multiple saturation proportion threshold value C _gx, number range 0.00-1.Typical case, character image C _g1=0.6, to specifying h≤H above _g1or h>=H _d1the interval color of form and aspect, saturation ratio lower than threshold value, BI _lY=BI _k2× BI _l, saturation ratio higher than threshold value, BI _lY=BI _k1× BI _l.Transition region is established in the above side of threshold value, arranges transition zone ranges 0.1.

(4-3) calculating pixel color saturation C _lexpansion, by pixel color saturation C _lexpand to C _lNcomputing unit performs:

C _LN＝C _L*BI _LY，

Judge, if C _lNbe greater than C _gLmust calculate and map:

C _LN＝C _gL+(C _LN-C _gL)/(C _maxLd-C _gL)*(C _maxL1-C _gL)

(5) by Color image pixel L, h and saturation C _lNnumerical computations is R, G and B value.

Call Color image pixel pattern transformation by reciprocal direction and normalizing block, calculating comprises:

The standard method using CIE to recommend, obtains with Color image pixel positive-going transition and the C obtained after L, h value remained unchanged and as calculated expansion _lNvalue is calculated as the red, green and blue tristimulus values of image.This algorithm is the inverse operation that above step (3) calculates, calculate white field needed for CIEXYZ tristimulus values by pixel color CIELAB spatial parameter and be similarly D65, calculate 3 × 3 matrix coefficients needed for rgb value by pixel color CIEXYZ tristimulus values and to be inverted acquisition by above step (3) matrix 3 × 3 used coefficient:

$\left[\begin{array}{ccc}3.2406& -0.9689& 0.0557\\ -1.5372& 1.8758& -0.2040\\ -0.4986& 0.0415& 1.0570\end{array}\right]$

Round respectively R, G and B value calculated, and turn to 255 to the numerical value specification being greater than 255, the numerical value specification being less than 0 turns to 0.Above step (3) (4) (5) calculation process as Figure 2-3.

The FECr algorithm flow that the whole pixel of image performs above-mentioned color digital image successively completes described calculating, and image just completes the conversion of visually-perceptible high-fidelity.

Embodiment 2 uses the canonical system of FECr algorithm of the present invention

11, using hard disc of computer HD as the typical carriers submitting FECr algorithm to, the carrier of said function also comprises CD, DVD, USB flash disk etc., and through authorizing by network call FECr algorithm.FECr algorithm is called by computer CPU+GPU with program mode (PM), runs in RAM.Color digital image is stored in hard disc of computer and is called by FECr algorithm routine, stores back in hard disk after FECr algorithm process again.View data can copy in the carriers such as CD, DVD, USB flash disk and other hard disk, also can be transmitted through the network to assigned address.

FECr algorithm routine can process single-frame images and frame sequence image.But the uncompressed forms such as single-frame images form .GIF .bmp, may also be the compressed formats such as .jpg.Frame sequence picture format is general .MOV .AVI etc., also can use special I/O process related pattern file.The display quantity of real-time viewing FECr algorithmic transformation image effect can configure as required.System is as shown in Fig. 8-1.

1.2, the typical apply using television set master chip as FECr algorithm IP, R, G and B each color range look-up table that in IP, gamma correction module uses can arrange according to gamma special in television set master chip and adjust.System is as shown in Fig. 8-2.

1.3, the typical apply using television set as FECr algorithm ASIC, arranges the I/O mated with television set and obtains video image color RGB data.System is as shown in Fig. 8-3.

1.4, the equipment applying FECr algorithm ASIC also comprises notebook computer, panel computer, mobile phone, game machine, LCD display, computer display card etc., and system as shown in fig. 8-4.

Claims (10)

1. color digital image carries out the method for visually-perceptible high-fidelity conversion, it is characterized in that, said method comprising the steps of:

(1) obtain color digital image pixel color R, L, C and h numerical value of G and B numerical value in CIELAB space, wherein, h is hue angle, and L is brightness, C is saturation;

(2) pixel color merger enters form and aspect plane and brightness sequence,

Enter corresponding reference colours phase face with the merger of hue angle h value, enter corresponding bright sequence with lightness l value merger;

(3) expansion of pixel color saturation C is completed,

(3-1) determine that pixel color saturation maps flex point C _gL:

C _gL＝C _maxL1×X _S1

Wherein, C _maxL1for pixel color to enter the brightness sequence maximum saturation angle value of form and aspect plane in the merger of equipment colour vision aware space, X _s1for the proportionality coefficient arranged, exemplary value scope 0.65-0.95;

(3-2) the saturation expansion ratio BI of this brightness sequence is calculated _l:

BI _L＝C _maxLd/C _maxL1

Wherein, C _maxLdfor the intensity value of pixel color same brightness sequence on identical form and aspect plane color equivalent border, visible light colors visually-perceptible space;

(3-3) saturation expansion ratio regulation and control coefficient B is set _iKx:

B _ILY＝B _IL×B _IKx

Wherein, B _iKxallow to arrange multiple, be respectively used to specified requirements, exemplary value scope 0.00-1, B _iLYfor regulating and controlling rear saturation expansion proportional numerical value;

(3-4) pixel color saturation is C _l, C _lpixel color saturation after expansion is C _lN, calculating pixel color saturation is expanded:

C _LN＝C _L×BI _LY

As C _lNbe greater than C _gLthen calculate it to map:

C _LN＝C _gL+(C _LN-C _gL)/(C _maxLd-C _gL)×(C _maxL1-C _gL)；

(4) by Color image pixel brightness L, hue angle h and after step (3) expansion the saturation C that obtains _lNnumerical computations is specification R, G and B value.

2. method according to claim 1, is characterized in that, color digital image pixel color R, G and B numerical transformation are L, C and h parameter in CIELAB space, obtains by the following method:

2.1 use the white field of equipment or image nominal and R, G and B three primary colors to specify parameter, and the standard method that application CIE recommends, is calculated as CIEXYZ tristimulus values and CIELAB space L, C and h value, comprises by image pixel RGB tristimulus values:

With brightness when sRGB space RGB three primary colors chromaticity and D65 white field CIEXYZ tristimulus values calculating RGB three primary colors maximum saturation:

Y _r,max＝0.2126 Y _g,max＝0.7152 Y _b,max＝0.0722

Application above calculating color RGB numerical value is converted to 3 × 3 matrix coefficients needed for CIEXYZ tristimulus values:

$\left[\begin{array}{ccc}0.4124& 0.3576& 0.1805\\ 0.2126& 0.7152& 0.0722\\ 0.0193& 0.1192& 0.9505\end{array}\right];$

2.2 non-standard equipments show CIEXYZ tristimulus values when image needs the white field of computing equipment and R, G and B three primary colors maximum saturation:

2.2.1 standard spectral photometric instrument is used, the conveniently white field tristimulus values X of criterion equipment _w', Y _w' and Z _w', calculate white field normalization coefficient K ₁:

K ₁＝100/Y _w’

The CIEXYZ tristimulus values of the white field of computing equipment:

X _w＝X _w’×K ₁ Y _w＝Y _w’×K ₁ Z _w＝Z _w’×K ₁，

2.2.2 standard spectral photometric instrument is used, the tristimulus values conveniently under specification difference measuring equipment RGB three primary colors maximum saturation condition: X _r', Y _r' and Z _r', X _g', Y _g' and Z _g', X _b', Y _b' and Z _b' calculate trichromatic CIEXYZ tristimulus values respectively:

X _r,max＝X _r’×K ₁ Y _r,max＝Y _r’×K ₁ Z _r,max＝Z _r’×K ₁

X _g,max＝X _g’×K ₁ Y _g,max＝Y _g’×K ₁ Z _g,max＝Z _g’×K ₁

X _b,max＝X _b’×K ₁ Y _b,max＝Y _b’×K ₁ Z _b,max＝Z _b’×K ₁，

CIEXYZ tristimulus values during the three primary colors maximum saturation that 2.3 use calculate above, 3 × 3 matrix coefficients in standard method described in alternative steps 2.1, by equipment nominal white field CIEXYZ tristimulus values described in the white field CIEXYZ tristimulus values alternative steps 2.1 calculated, calculate CIELAB space L, C and h numerical value.

3. method according to claim 1, is characterized in that, the form and aspect plane of described pixel color and brightness sequence merger, obtains by the following method:

With 0-359 totally 360 integers represent reference colours phase face respectively, enter corresponding reference colours phase face with the merger that rounds up of color form and aspect h value; With 0-100 totally 101 integers represent brightness L consensus sequence in form and aspect plane respectively, enter corresponding bright sequence with the merger that rounds up of colour brightness L value in form and aspect plane.

4. method according to claim 1, is characterized in that, the maximum saturation angle value of equipment colour vision aware space form and aspect plane brightness sequence, obtains by the following method:

The equipment of 4.1 pairs of use red, green and blue three primary colors display color digital pictures, the white field of use equipment nominal and red, green and blue three primary colors regulation parameter, the standard method that application CIE recommends, by whole colors that equipment red, green and blue three primary colors synthesize, be converted to CIEXYZ tristimulus values and CIELAB space L, C and h value, comprise:

With brightness when sRGB space RGB three primary colors chromaticity and D65 white field CIEXYZ tristimulus values calculating RGB three primary colors maximum saturation:

Y _r,max＝0.2126 Y _g,max＝0.7152 Y _b,max＝0.0722

Application above calculating color RGB numerical value is converted to 3 × 3 matrix coefficients needed for CIEXYZ tristimulus values:

$\left[\begin{array}{ccc}0.4124& 0.3576& 0.1805\\ 0.2126& 0.7152& 0.0722\\ 0.0193& 0.1192& 0.9505\end{array}\right];$

4.2 non-standard equipments need the white field of computing equipment and the trichromatic CIEXYZ tristimulus values of red, green and blue:

4.2.1 standard spectral photometric instrument is used, the conveniently white field tristimulus values X of criterion equipment _w', Y _w' and Z _w', calculate white field normalization coefficient K ₁:

K ₁＝100/Y _w’

The CIEXYZ tristimulus values of the white field of computing equipment:

X _w＝X _w’×K ₁ Y _w＝Y _w’×K ₁ Z _w＝Z _w’×K ₁，

4.2.2 standard spectral photometric instrument is used, the tristimulus values conveniently under specification difference measuring equipment red, green and blue three primary colors maximum saturation condition, X _r', Y _r' and Z _r', X _g', Y _g' and Z _g', X _b', Y _b' and Z _b' calculate trichromatic CIE XYZ tristimulus values more respectively:

X _r,max＝X _r’×K ₁ Y _r,max＝Y _r’×K ₁ Z _r,max＝Z _r’×K ₁

X _g,max＝X _g’×K ₁ Y _g,max＝Y _g’×K ₁ Z _g,max＝Z _g’×K ₁

X _b,max＝X _b’×K ₁ Y _b,max＝Y _b’×K ₁ Z _b,max＝Z _b’×K ₁，

4.3 use the primary colors CIEXYZ tristimulus values calculated above, 3 × 3 matrix coefficients in standard method described in alternative steps 4.1, with equipment nominal white field CIEXYZ tristimulus values described in the white field CIEXYZ tristimulus values alternative steps 4.1 calculated, calculate CIELAB space L, C and h numerical value;

The 4.4 armamentarium spatial colors that will calculate, enter corresponding reference colours phase face with the merger that rounds up of form and aspect h value, then enter corresponding bright sequence with the lightness l value merger that rounds up;

4.5 with the maximum saturation C of the whole brightness sequence of form and aspect plane _maxL1numeric representation color boundaries, and to maximum saturation angle value C from form and aspect plane _maxh1the brightness L had _cmaxh1to minimum brightness L=0 brightness sequence interval corresponding to color boundaries, correct wherein C with standard linear interpolation method _maxL1non-ly smoothly successively decrease or fill up disappearance.

5. method according to claim 1, is characterized in that, the intensity value C of described pixel color same brightness sequence on identical form and aspect plane color equivalent border, visible light colors visually-perceptible space _maxLd, obtain by the following method:

5.1 obtain the maximum saturation C of 0 °, visible light colors visually-perceptible space to 359 ° of assorted phase face _maxh2and brightness L _cmaxh2;

5.2 pairs of 0 ° to 359 ° assorted phase face, calculate visible light colors space C _maxh2with device color spaces C _maxh1ratio value B _maxh:

B _maxh＝C _maxh2/C _maxh1

Set scale coefficient F _x1with equivalent coefficient F _x2, wherein, F _x1exemplary value scope 2.50-6.00, F _x2exemplary value scope 1.50-2.50, calculates B _maxhstandardization equivalents ratio B _maxd:

B _maxhvalue is greater than F _x1form and aspect plane standardization calculate:

B _maxd=(B _maxh-F _x1interval maximum scale value-the F of)/(ratio _x1) × 0.1+F _x2

B _maxhvalue is less than or equal to F _x1be greater than (F _x1-1) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-1))/(interval maximum scale value-(F of ratio _x1-1)) × 0.05+ (F _x2-0.05)

B _maxhvalue is less than or equal to (F _x1-1) (F is greater than _x1-1.5) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-1.5))/(interval maximum scale value-(F of ratio _x1-1.5)) × 0.05+ (F _x2-0.1)

B _maxhvalue is less than or equal to (F _x1-1.5) (F is greater than _x1-2) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-2))/(interval maximum scale value-(F of ratio _x1-2)) × 0.1+ (F _x2-0.2)

B _maxhvalue is less than or equal to (F _x1-2) (F is greater than _x1-2.5) standardization of form and aspect plane calculates:

B _maxd=(B _maxh-(F _x1-2.5))/(interval maximum scale value-(F of ratio _x1-2.5)) × 0.05+ (F _x2-0.25)

B _maxhvalue equals (F _x1-2.5) and following form and aspect plane standardization calculate:

B _maxd=B _maxhinterval maximum scale value × 0.05+ (the F of/ratio _x2-0.3);

The maximum saturation equivalent C of 5.3 calculating visible light colors space form and aspect planes _maxhd:

C _maxhd＝C _maxh1×B _maxd

5.4 is saturation C at abscissa, and ordinate is the cartesian coordinate plane of brightness L, with C _maxh2and L _cmaxh2value indicates maximum saturation coordinate points D _maxh2, from a D _maxh2connect ordinate L=100 point, line indicates C _maxhd, the brightness sequence value that its ordinate value rounds up is designated as L _cmaxhd, its coordinate points is designated as D _maxhd;

5.5 indicate the equipment color boundaries of identical form and aspect plane at coordinate plane, then indicate D _maxhdto L=0 point line, under making it guarantee the prerequisite that the maximum saturation angle value of corresponding bright sequence in brightness section is smoothly successively decreased, contain equipment color boundaries, by the D after adjusting _maxhdto L=0 point line and D _maxhdto L=100 point line, form the intensity value C of pixel color same brightness sequence on identical form and aspect plane color equivalent border, visible light colors visually-perceptible space _maxLd.

6. method according to claim 5, is characterized in that, the alleged maximum saturation C of 0 °, visible light colors visually-perceptible space to 359 ° of assorted phase face in step 5.1 _maxh2and brightness L _cmach2, obtain by the following method:

6.1 with x, y and z numerical value of CIE1931XYZ standard colorimetric observer spectral tristimulus value medium wavelength 380nm to 780nm interval 5nm, and the white field CIEXYZ tristimulus values of computing equipment color space application, the method of recommending with CIE calculates L, C and h numerical value, and to round up merger form and aspect plane with h value, take L and the C numerical value of form and aspect plane in wherein 38 ° to 317 ° form and aspect intervals, another linear interpolation calculates L and the C value of blank form and aspect plane wherein, the maximum saturation C using L and C value as the corresponding form and aspect plane in visible light colors visually-perceptible space _maxh2and brightness L _cmach2;

The 6.2 white field CIEXYZ tristimulus values applied with CIERGB color space red, green and blue three primary colors canonical parameter and computing equipment color space, calculate CIELAB space L, C and h numerical value generating whole red, green and blue three primary colors synthesis color, comprising:

With CIERGB space RGB three primary colors chromaticity parameter and the white field parameters of D65, calculate 3 × 3 matrix coefficients with same procedure in claim 4:

X _r,max＝0.4108 Y _r,max＝0.1481 Z _r,max＝0

X _g,max＝0.3210 Y _g,max＝0.8401 Z _g,max＝0.0105

X _b,max＝0.2185 Y _b,max＝0.0118 Z _b,max＝1.0783

In the form and aspect plane of merger, select 0 ° to 37 ° and 318 ° to 359 ° form and aspect planes, and extract wherein maximum saturation C _maxh2and brightness L _cmach2numerical value.

7. method according to claim 1, is characterized in that, described method also comprise arrange multiple saturation expansion ratio regulation and control coefficient B I _kxstep, the number range 0.00-1 of coefficient, allows with (BI _k1× BI _l) and (BI _k2× BI _l) as the pixel practical application saturation expansion ratio under different specified requirements.

8. method according to claim 1, is characterized in that, described method also comprises and arranges multipair form and aspect plane interval border H _dxand H _gxstep, border form and aspect plane number range 0 °-359 °, uses the saturation different from outside interval to expand ratio to the color that arranges in form and aspect plane interval; Arrange intermediate color separately inside form and aspect plane interval border, interval number range 0-20, in regulation and control form and aspect interval border, color saturation expansion ratio is smoothly transitted into outside border.

9. method according to claim 1, is characterized in that, described method also comprises and arranges multiple saturation threshold value C _gxstep, saturation threshold value scope 0.00-1, threshold value uses the saturation ratio value boundary of different saturation expansion ratio as same brightness sequence color; Transition region is set in threshold value high-end side, the saturation ratio value scope 0.00-0.2 of transition region; In saturation threshold application when bulletin colour is interval mutually, realize saturation proportion threshold value in the calculating of form and aspect edge transitional region and seamlessly transit.

10. pair color digital image carries out the system of visually-perceptible high-fidelity conversion, it is characterized in that, described system comprises:

(1) the equipment colour vision aware space form and aspect plane color boundaries computing module of display color digital picture, comprising:

(1-1) the red, green and blue tristimulus values of device color spaces is transformed to CIELAB space L, C and h value computing unit,

(1-2) equipment colour vision aware space form and aspect plane color edge extraction unit, corresponding reference colours phase face is entered with the form and aspect h value merger equipment color that rounds up, enter corresponding bright sequence with the merger that rounds up of L value, extract the color maximum saturation angle value C of each brightness sequence of form and aspect plane _maxL1, calculate baseline values as the color boundaries of this form and aspect plane,

(1-3) the intensity value C of pixel place brightness sequence in equipment form and aspect plane color boundaries _maxL1smooth unit, selects maximum saturation angle value C in form and aspect plane _maxh1the brightness L had _cmaxh1to minimum brightness L=0 brightness sequence interval corresponding to the intensity value C of pixel place brightness sequence in equipment form and aspect plane color boundaries _maxL1, calculate smooth boundary with standard linear interpolation algorithm, make up C _maxL1non-ly smoothly successively decrease or fill up disappearance, the color boundaries calculated and by brightness L _cmaxh1the interval corresponding color maximum saturation angle value of brightness sequence to L=100, with C _maxL1represent, form the application color boundaries of this form and aspect plane;

(2) pixel place brightness sequence is at the borderline intensity value C of visible ray form and aspect plane color equivalent _maxLd computing module;

(3) color digital image pixel color pattern forward conversion and merger form and aspect plane and brightness sequence module, comprising:

(3-1) color digital image pixel color rgb value is converted to the computing unit of L, C and h value in CIELAB space, wherein, h is hue angle, and L is brightness, C is saturation,

(3-2) pixel color form and aspect plane and brightness sequence Merging unit, be 360 reference colours phase face by color of image spatial division, corresponding reference colours phase face is entered with the merger that rounds up of form and aspect h value, brightness L scope in form and aspect plane is divided into 101 consensus sequences, enters corresponding bright sequence with the lightness l value merger that rounds up;

(4) Color image pixel intensity value expansion module, comprising:

(4-1) pixel color saturation expansion ratio BI _lcomputing unit:

BI _L＝C _maxLd/C _maxL1

Wherein, C _maxLdfor pixel place brightness sequence is in the borderline intensity value of visible ray form and aspect plane color equivalent, C _maxL1for the intensity value of pixel place brightness sequence in equipment form and aspect plane color boundaries,

(4-2) saturation expansion ratio BI _lcharacterization regulation and control computing unit, comprising:

(4-2-1) saturation expansion ratio regulation and control coefficient B I is set _kx, number range 0.00-1,

BI _LY＝BI _L×BI _Kx

Wherein, BI _kxallow to arrange and be multiplely respectively used to specified requirements, BI _lYfor regulating and controlling rear saturation expansion ratio,

(4-2-2) the interval border H in pairs of form and aspect plane is set _dxand H _gx, number range 0 °-359 °, H _dxand H _gxallow to arrange and be multipairly respectively used to specified requirements:

Color h>=H _dxwith h≤H _gx, BI _lY=BI _l× BI _k2

All the other colors, BI _lY=BI _l× BI _k1

Inside border, form and aspect plane transition region arranges number range 0-20,

(4-2-3) saturation proportion threshold value C is set _gx, number range 0.00-1, C _gxallow to arrange and be multiplely respectively used to specified requirements:

C _gxbe worth following color, BI _lY=BI _l× BI _k2

C _gxbe worth above color, BI _lY=BI _l× BI _k1

C _gxbe worth high-end side transition region and number range 0.00-0.2 be set,

(4-3) pixel color saturation maps flex point C _gLcomputing unit:

C _gL＝C _maxL1×X _S1

Set scale coefficient X _s1number range 0.65-0.95,

(4-4) pixel color saturation C _lexpand to pixel color saturation C _lNcomputing unit:

C _LN＝C _L×BI _LY，

If C _lNbe greater than C _gLthen calculate mapping:

C _LN＝C _gL+(C _LN-C _gL)/(C _maxLd-C _gL)×(C _maxL1-C _gL)；

(5) Color image pixel pattern transformation by reciprocal direction and normalizing block, described calculating comprises L, h of Color image pixel and expands the saturation C obtained through module (4) _lNnumerical computations is specification R, G and B value.