CN2838183Y - Device for improving video image effect dynamically - Google Patents

Abstract

The utility model relates to a device for improving video image visual effect dynamically, which comprises a brightness input circuit which is connected with a circuit, a statistical circuit, a brightness uniformity testing circuit, an inflection point calculating circuit, a brightness mapping circuit and a brightness output circuit, wherein an inflection point calculating circuit is also connected with a contrast control coefficient input circuit. After values, such as a maximum value of the brightness, a minimal value of the brightness, a mean value of the brightness, etc., of an image are counted by the utility model, the utility model is used for detecting whether the image brightness is uniformly distributed, and different inflection point positions are arranged according to the uniform degree of the brightness distribution to obtain a brightness mapping function; finally, after the brightness which is input is mapped, the brightness is output. Piecewise linear expansion is adopted by the device for improving video image visual effect dynamically provided by the utility model, grey scale areas of some sections can be selectively stretched to enable a curve to smoothly change, the image quality can be improved and sudden flicker can not occur in the scene of gradual change of the brightness.

Description

A kind of device of dynamic raising video image effect of vision

Technical field

The utility model relates to a kind of device of dynamic raising video image effect of vision.

Background technology

Since actual photographed to the grey scale change scope of video image often allow the grey scale change scope less than the maximum of image display system, the figure kine bias is dark or bright partially, the contrast deficiency, visual effect is undesirable.The main purpose of contrast expansion is the grey scale change scope that increases image, and the gray-level of rich image improves visual perception.Contrast expansion is to improve a kind of strong means of video image effect.

It is three kinds of different algorithms with the luminance proportion algorithm that existing picture contrast expansion algorithm, black are expanded algorithm, usually at different video scenes, with be three kinds of different processing modes: it is in darker scene that black is expanded, suitably raise the brightness of image, make visible details more; Luminance proportion is smooth picture brightness when the scene high brightness, relaxes oversaturated scene; Contrast expansion then is the contrast of video image of effectively stretching, and makes black more blackly, and white is whiter.Diverse ways is to be applied in different occasions, if in a continuous transition scene (existing dark scene also has the bright field scape), possible these three kinds of algorithms can both switch to, because the difference of the manifestation mode of algorithm might be brought the flicker of moment.

The utility model content

The device of a kind of dynamic raising video image effect of vision that the utility model provides, picture contrast expansion algorithm, black are expanded algorithm and the integrated processing of luminance proportion algorithm, obtain different mapping functions by the flex point under the calculating different situations and improve picture contrast, the flicker problem in the time of can effectively separating the annual reporting law switching.

In order to achieve the above object, the utility model provides a kind of device of dynamic raising video image effect of vision, and it comprises:

One brightness input circuit, its view picture video image to input calculates luminance graph, obtain representing monochrome information function f at the pixel of the capable j row of image i (i, j);

One statistics circuit, its input connects the output of brightness input circuit; This statistical circuit comprises successively and to connect by circuit:

One image brightness mean value computation device, it is made up of brightness accumulator, number of pixels accumulator and divider, calculates the brightness average M of entire image;

One maximum brightness detector calculates brightness maximum Max;

One minimum brightness detector calculates brightness minimum M in;

One adder is used for statistic histogram, and this adder also connects a SRAM memory, is used to store the histogram array data;

One block statistics module, it comprises N * N image brightness mean value computation device that connects successively, maximum average detector and minimum mean detector; This block statistics module is divided into N * N piece with image, calculates every brightness average respectively by N * N image brightness mean value computation device, and exports maximum average detector and minimum mean detector to, obtains maximum average M _MaxWith minimum mean M _Min

The even testing circuit of one brightness, the output of its input connection statistics circuit judges in conjunction with histogram whether image belongs to the uneven situation of Luminance Distribution;

The even testing circuit of this brightness comprises three comparison modules and an AND circuit, and the output of described three comparison modules all connects the input of AND circuit; When the condition of three comparison modules satisfies simultaneously, when promptly following judgement formula (1) is set up,

AND circuit output brightness irregularities flex point triggering signal; When having any one condition not satisfy in three comparison modules, the even flex point triggering signal of AND circuit output brightness;

In the following formula (1), H () is the pixel count of this image on certain gray scale, and Sum is the number of total picture element of entire image, C ₁, C ₂And C ₃All be constant, C ₁Represent maximum average M _MaxWith minimum mean M _MinThe amplitude that differs, general C ₁Value between 120～200; C ₂Represent maximum average M _MaxWith minimum mean M _MinNear tonal range, general C ₂Value between 5～30; C ₃For at maximum average M _MaxWith minimum mean M _MinNear point accounts for the ratio of full figure, general C ₃Value between 0.3～0.5;

One contrast adjustment factor input circuit, output contrast adjustment coefficient k;

One flex point computing circuit, its input connects the output of even testing circuit of brightness and statistical circuit, is used for calculating corner position; The input of this flex point computing circuit also connects the output of contrast adjustment coefficient input circuit, receives the contrast adjustment coefficient k of its output, and this flex point computing circuit comprises brightness irregularities flex point computing module and the even flex point computing module of brightness;

When the flex point computing circuit received brightness irregularities flex point triggering signal, brightness irregularities flex point computing module was worked, and the result of operation result as the flex point computing circuit exported: choose 2 flex point A (Yin ₁, Yout ₁) and B (Yin ₂, Yout ₂), wherein

Yin ₁＝M _min+C ₄

Yin ₂＝M _max-C ₅

Yout ₁＝Yin ₁+C ₆

Yout ₂＝Yin ₂-C ₇

(2)

Described formula (2) is illustrated in [Min, Yin ₁], [Yin ₂, Max] carry out gray scale in these two zones and stretch; C ₄, C ₅, C ₆And C ₇All be constant, C ₄Expression flex point A and minimum mean M _MinBetween distance; C ₅Expression flex point B and maximum average M _MaxBetween distance; C ₆The stretch range of expression flex point A; C ₇The stretch range of expression flex point B;

When the flex point computing circuit receives the even flex point triggering signal of brightness, the even flex point computing module work of brightness, and with the result output of result as the flex point computing circuit: choose flex point A (Yin ₁, Yout ₁) and B (Yin ₂, Yout ₂), wherein, Yin ₁, Yin ₂For needs carry out 2 flex points that brightness stretches, they on the both sides of average, provide by following formula respectively:

Yin ₁＝M-a ₁

Yin ₂＝M+a ₂

(3)

In the formula (3), a ₁, a ₂Be the distance that needs stretching, be variable, choosing a ₁, a ₂Value the time, need guarantee the Yin that calculates ₁, Yin ₂Within the scope of [Min, Max];

Yout ₁, Yout ₂Be the flex point of the stretch zones of output image correspondence, it on the both sides of image brightness average M, provides by following formula respectively:

Yout ₁＝Yin ₁+k×(-C ₈×a ₁+(H/2+d-M))×(Yin ₂-Yin ₁)

Yout ₂＝Yin ₂+k×(C ₈×a ₂+(H/2-M))×(Yin ₂-Yin ₁)

(4)

In the formula (4), k is the contrast adjustment coefficient, and it is by contrast adjustment coefficient input circuit input, and when k is big more, then contrast is big more; K is more little, and then contrast is more little, and is approaching more with former figure; H is the brightness space maximum permissible value, as at YcbCr space, then H=235; As at HSV space, then H=255; D is a default little positive number, is calculating Yout ₁Process in, add a positive number d, be that suitable heightens because human eye is insensitive to the dark place, can make the image visibility of dark place high; Constant C ₈The flex point of choosing the final output of decision be slope be 1 straight line above or below; Formula (4) is subjected to (Yin ₂-Yin ₁) influence, promptly as (Yin ₂-Yin ₁) when bigger, the contrast adjustment degree is big, as (Yin ₂-Yin ₁) when smaller, the contrast adjustment degree is unsuitable excessive;

One brightness mapping circuit, its input connect the output of brightness input circuit, statistical circuit and flex point computing circuit respectively, and figure shines upon to original brightness, are dynamically improved contrast final brightness output f afterwards _Out(i, j);

Described brightness mapping circuit comprises comparator, a class mapping block, two class mapping blocks and three class mapping blocks;

Described comparator for brightness f (i j) screens, when Min≤f (i, j)＜Yin ₁The time, export class mapping triggering signal; Work as Yin ₁≤ f (i, j)＜Yin ₂The time, export two classes mapping triggering signal; Work as Yin ₂≤ f (i, j)≤during Max, export three classes mapping triggering signal;

The input of a described class mapping block connects the output of comparator, and this module is carried out mapping transformation to luminance graph after receiving class mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{({\mathrm{Yout}}_1-\mathrm{Min})f(i,j)+\mathrm{Min}({\mathrm{Yin}}_1-{\mathrm{Yout}}_1)}{{\mathrm{Yin}}_1-\mathrm{Min}};$

The input of described two class mapping blocks connects the output of comparator, and this module is carried out mapping transformation to luminance graph after receiving two classes mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{({\mathrm{Yout}}_2-{\mathrm{Yout}}_1)f(i,j)+{\mathrm{Yin}}_2{\mathrm{Yout}}_1-{\mathrm{Yin}}_1{\mathrm{Yout}}_2}{{\mathrm{Yin}}_2-{\mathrm{Yin}}_1};$

The input of described three class mapping blocks connects the output of comparator, and this module is carried out mapping transformation to luminance graph after receiving three classes mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{(\mathrm{Max}-{\mathrm{Yout}}_2)\×f(i,j)+\mathrm{Max}({\mathrm{Yout}}_2-{\mathrm{Yin}}_2)}{\mathrm{Max}-{\mathrm{Yin}}_2};$

One brightness output module, its input connects the output of brightness mapping circuit, exports after the luminance transformation after being used for contrast strengthened is returned the original form of vision signal.

The brightness value that described brightness input circuit calculates can be the Y in the YUV model, or the V in the HSV model, or the I in the HIS model, perhaps the brightness of being derived by other rational brightness-formula.

The device of the dynamic raising video image effect of vision that the utility model provides, select piecewise linearity expansion commonly used for use, stretch selectively between certain section gray area, thereby improve picture quality, promptly no matter image is in bright field or details in a play not acted out on stage, but told through dialogues, all takes the piecewise function of three line segments, and the selection of two flex points on the piecewise function changes along with the conversion of brightness average, the variation of curve smoothing can be made, unexpected flicker can be in the scene that brightness gradually changes, do not occurred.

Description of drawings

Fig. 1 is the general structure schematic diagram of the device of the dynamic raising video image effect of vision that provides of the utility model;

Fig. 2 is the structural representation of brightness input circuit of the present utility model;

Fig. 3 is the structural representation of statistical circuit of the present utility model;

Fig. 4 is the structural representation of the even testing circuit of brightness of the present utility model;

Fig. 5 is the structural representation of the brightness irregularities flex point computing module in the flex point computing circuit of the present utility model;

Fig. 6 is the structural representation of the even flex point computing module of brightness in the flex point computing circuit of the present utility model;

Fig. 7 is the structural representation of the class mapping block in the brightness mapping circuit of the present utility model;

Fig. 8 is the structural representation of two class mapping blocks in the brightness mapping circuit of the present utility model;

Fig. 9 is the structural representation of three class mapping blocks in the brightness mapping circuit of the present utility model.

Embodiment

The following preferred forms that specifies the device of a kind of dynamic raising video image effect of vision that the utility model provides according to Fig. 1～Fig. 9:

As shown in Figure 1, the utility model provides a kind of device of dynamic raising video image effect of vision, and it comprises:

One brightness input circuit 1 (as shown in Figure 2), if brightness value is transformed into the Y in YcbCr space, then comprise some multipliers and adder, its concrete connected mode is as follows: constant and video data are input in multiplier 101, multiplier 102 and the multiplier 103, the output of the output of multiplier 101 and multiplier 102 is input in the adder 104, the output of the output of multiplier 103 and adder 104 is input in the adder 105, obtains luminance signal.This circuit reads in entire image, and video image is calculated luminance graph, obtain representing monochrome information function f at the pixel of the capable j row of image i (i, j);

One statistics circuit 2 (as shown in Figure 3), its input connects the output of brightness input circuit 1; This statistical circuit comprises successively and to connect by circuit:

One image brightness mean value computation device, it is made up of brightness accumulator 201, number of pixels accumulator 208 and divider 202, calculates the brightness average M of entire image;

One maximum brightness detector 203 calculates brightness maximum Max;

One minimum brightness detector 204 calculates brightness minimum M in;

One adder 205 is used for statistic histogram, and this adder also connects a SRAM memory 206, is used to store the histogram array data;

One block statistics module, it comprises 2 * 2 image brightness mean value computation devices that connect successively, maximum average detector 207m and minimum mean detector 207n, each brightness mean value computation device is all by brightness accumulator (207a, 207b, 207c, 207d), number accumulator (207e, 207f, 207g, 207h) and divider (207i, 207j, 207k 207l) forms; This block statistics module is divided into 4 with image, calculates every brightness average respectively by 4 image brightness mean value computation devices, and exports maximum average detector 207m and minimum mean detector 207n to, obtains maximum average M _MaxWith minimum mean M _Min

The even testing circuit 3 of one brightness (as shown in Figure 4), the output of its input connection statistics circuit 2 judges in conjunction with histogram whether image belongs to the uneven situation of Luminance Distribution;

The even testing circuit of this brightness comprises three comparison modules and an AND circuit 308, and the output of described three comparison modules all connects the input of AND circuit 308.Comprise comparator 301,302,303 in three comparison modules, devices such as subtracter 304, accumulator 305,307, multiplier 306, concrete connected mode is as follows: the maximum average M that block statistics module 207 counts in the statistical circuit _MaxWith minimum mean M _MinThe output and the constant that are input to subtracter 304,304 are input to first comparator 301; The output of SRAM memory 206 is histogrammic array datas in the statistical circuit, it is input in the accumulator 305, the output pixel of number accumulator 208 sum and constant are input in the multiplier 306 in the statistical circuit, and the output of the output of accumulator 305 and multiplier 306 is input in second comparator 302; Histogrammic array data is input to accumulator 307, and the output of the output of accumulator 307 and multiplier 306 is input in the 3rd comparator 303; Whether uniformly the output of three comparators is input to and door 308, export brightness triggering signal with door 308.

When the condition of three comparison modules satisfies simultaneously, when promptly following judgement formula (1) is set up,

AND circuit 308 output brightness irregularities flex point triggering signals; When having any one condition not satisfy in three comparison modules, the even flex point triggering signal of AND circuit 308 output brightness;

In the following formula (1), H () is the pixel count of this image on certain gray scale, and Sum is the number of total picture element of entire image, C ₁, C ₂And C ₃All be constant, C ₁Represent maximum average M _MaxWith minimum mean M _MinThe amplitude that differs, general C ₁Value between 120～200; C ₂Represent maximum average M _MaxWith minimum mean M _MinNear tonal range, general C ₂Value between 5～30; C ₃For at maximum average M _MaxWith minimum mean M _MinNear point accounts for the ratio of full figure, general C ₃Value between 0.3～0.5;

One contrast adjustment factor input circuit 5, output contrast adjustment coefficient k;

One flex point computing circuit 4, its input connects the output of even testing circuit 3 of brightness and statistical circuit 2, is used for calculating corner position; The input of this flex point computing circuit 4 also connects the output of contrast adjustment coefficient input circuit 5, receives the contrast adjustment coefficient k of its output,

This flex point computing circuit 4 comprises brightness irregularities flex point computing module 401 and the even flex point computing module 402 of brightness;

Described brightness irregularities flex point computing module 401 (as shown in Figure 5) is made up of adder 401a, 401c and subtracter 401b, 401d, and concrete connected mode is as follows: the minimum mean M of statistical circuit 2 outputs _MinBe input to adder 401a with constant, adder 401a is output as the initial value Yin of first flex point ₁The maximum average M of statistical circuit 2 outputs _MaxBe input to subtracter 401b with constant, subtracter 401b is output as the initial value Yin of second flex point ₂The output of adder 401a and constant are input among another adder 401c, and adder 401c is output as the value Yout after first flex point stretches ₁The output of subtracter 401b and constant are input among another subtracter 401d, and subtracter 401c is output as the value Yout after the two or two flex point stretches ₂

The even flex point computing module 402 of described brightness (as shown in Figure 6) is made up of adder 402b, 402h, 402j, 402m, subtracter 402a, 402c, 402d, 402e, 402i and multiplier 402f, 402g, 402k, 402l, concrete connected mode is as follows: the brightness average M and a constant of statistical circuit 2 outputs are input among the subtracter 402a, a brightness average M and a constant are input among the adder 402b, obtain the initial value Yin of two flex points ₁And Yin ₂These two values are input among the subtracter 402c; A brightness average M and a constant are input among the subtracter 402d, its output and constant are input among another subtracter 402e again, the output k of the output of this subtracter and contrast adjustment coefficient input circuit is input among the multiplier 402f jointly, the output of this multiplier and subtracter 402c are input among the multiplier 402g jointly, the output of this multiplier and the initial value Yin of first flex point ₁, 402a output be input among the adder 402h value Yout of first flex point after obtaining stretching jointly ₁A brightness average M and a constant are input among the subtracter 402i, its output and a numerical value are input among the adder 402j again, the output k of the output of this adder and contrast adjustment coefficient input circuit is input among the multiplier 402k jointly, the subtracter 402c that the output of this multiplier and two flex point initial values are subtracted each other is input among the multiplier 402l initial value Yin of the output of this multiplier and second flex point jointly ₂, 402b output be input among the adder 402m value Yout of second flex point after obtaining stretching jointly ₂

When flex point computing circuit 4 received brightness irregularities flex point triggering signal, brightness irregularities flex point computing module 401 was worked, and the result is exported as the result of flex point computing circuit 4: choose 2 flex point A (Yin ₁, Yout ₁) and B (Yin ₂, Yout ₂), wherein

Yin ₁＝M _min+C ₄

Yin ₂＝M _max-C ₅

Yout ₁＝Yin ₁+C ₆

Yout ₂＝Yin ₂-C ₇

(2)

Described formula (2) is illustrated in [Min, Yin ₁], [Yin ₂, Max] carry out gray scale in these two zones and stretch; C ₄, C ₅, C ₆And C ₇All be constant, C ₄Expression flex point A and minimum mean M _MinBetween distance; C ₅Expression flex point B and maximum average M _MaxBetween distance; C ₆The stretch range of expression flex point A; C ₇The stretch range of expression flex point B;

When flex point computing circuit 4 receives the even flex point triggering signal of brightness, even flex point computing module 402 work of brightness, and with the result output of result as flex point computing circuit 4: choose flex point A (Yin ₁, Yout ₁) and B (Yin ₂, Yout ₂), wherein, Yin ₁, Yin ₂For needs carry out 2 flex points that brightness stretches, they on the both sides of average, provide by following formula respectively:

Yin ₁＝M-a ₁

Yin ₂＝M+a ₂

(3)

In the formula (3), a ₁, a ₂Be the distance that needs stretching, be variable, choosing a ₁, a ₂Value the time, need guarantee the Yin that calculates ₁, Yin ₂Within the scope of [Min, Max];

Yout ₁, Yout ₂Be the flex point of the stretch zones of output image correspondence, it on the both sides of image brightness average M, provides by following formula respectively:

Yout ₁＝Yin ₁+k×(-C ₈×a ₁+(H/2+d-M))×(Yin ₂-Yin ₁)

Yout ₂＝Yin ₂+k×(C ₈×a ₂+(H/2-M))×(Yin ₂-Yin ₁)

(4)

In the formula (4), k is the contrast adjustment coefficient, and k is big more, and then contrast is big more; K is more little, and then contrast is more little, and is approaching more with former figure; H is the brightness space maximum permissible value, as at YcbCr space, then H=235; As at HSV space, then H=255; D is a default little positive number, is calculating Yout ₁Process in, add a positive number d, be that suitable heightens because human eye is insensitive to the dark place, can make the image visibility of dark place high; Constant C ₈The flex point of choosing the final output of decision be slope be 1 straight line above or below; Formula (4) is subjected to (Yin ₂-Yin ₁) influence, promptly as (Yin ₂-Yin ₁) when bigger, the contrast adjustment degree is big, as (Yin ₂-Yin ₁) when smaller, the contrast adjustment degree is unsuitable excessive;

One brightness mapping circuit 6, its input connects the output of brightness input circuit 1, statistical circuit 2 and flex point computing circuit 4, specifically is to say to be exactly output f (i, j) the output Min of statistical circuit 2 that the input of circuit 6 has circuit 1, Max, the output Yin of flex point computing circuit 4 ₂, Yout ₁, Yout ₂Figure shines upon to original brightness, is dynamically improved contrast final brightness output f afterwards _Out(i, j);

Described brightness mapping circuit comprises comparator 601, a class mapping block 602, two class mapping blocks 603 and three class mapping blocks 604;

Described comparator 601 for brightness f (i j) screens, when Min≤f (i, j)＜Yin ₁The time, export class mapping triggering signal; Work as Yin ₁≤ f (i, j)＜Yin ₂The time, export two classes mapping triggering signal; Work as Yin ₂≤ f (i, j)≤during Max, export three classes mapping triggering signal;

The input of a described class mapping block 602 (as shown in Figure 7) connects the output of comparator 601, this module comprises some multipliers, divider, adder and subtracter, and its concrete connected mode is as follows: the value Yout of first flex point after the output of flex point computing circuit 4 stretches ₁Be input to a subtracter 602a with the output brightness minimum M in of statistical circuit 2, (i j) is input among the multiplier 602b the current figure image point of the output f of its output and brightness input circuit 1, the value Yout of first flex point after the output of flex point computing circuit 4 stretches ₁Initial value Yin with first flex point ₁Be input to a subtracter 602c, the output brightness minimum M in of the output of this subtracter and statistical circuit 2 is input among the multiplier 602d, and the output of this multiplier and the output of 602b are input among the adder 602e jointly; The initial value Yin of first flex point of output of flex point computing circuit 4 ₁Be input to jointly among the subtracter 602f with the output brightness minimum M in of statistical circuit 2, the output of this subtracter and adder 602e is input among the divider 602g, obtains being output as the image f after contrast strengthens _Out(i, j).This module is carried out mapping transformation to luminance graph after receiving class mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{({\mathrm{Yout}}_1-\mathrm{Min})f(i,j)+\mathrm{Min}({\mathrm{Yin}}_1-{\mathrm{Yout}}_1)}{{\mathrm{Yin}}_1-\mathrm{Min}};$

The input of described two class mapping blocks 603 (as shown in Figure 8) connects the output of comparator 601.This module comprises some multipliers, divider, adder and subtracter, and its concrete connected mode is as follows: the value Yout of first flex point after the output of flex point computing circuit 4 stretches ₁With stretch after the value Yout of the two or two flex point ₂Be input to a subtracter 603a, (i j) is input among the multiplier 603b the current figure image point of the output f of its output and brightness input circuit 1; The value Yout of first flex point after the output of flex point computing circuit 4 stretches ₁Initial value Yin with second flex point ₂Be input to a multiplier 603c, the value Yout of second flex point after the output of flex point computing circuit 4 stretches ₂Initial value Yin with first flex point ₁Be input among the multiplier 603d, the output of the output of this multiplier and multiplier 603c is input among the subtracter 603e, and the output of the output of this subtracter and multiplier 603b is input among the adder 603f jointly; The initial value Yin of first flex point of output of flex point computing circuit 4 ₁Initial value Yin with second flex point ₂Be input to jointly among the subtracter 603g, the output of the output of this subtracter and adder 603f is input among the divider 603h, obtains being output as the image f after contrast strengthens _Out(i, j).This module is carried out mapping transformation to luminance graph after receiving three classes mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{({\mathrm{Yout}}_2-{\mathrm{Yout}}_1)f(i,j)+{\mathrm{<figure-callout\; id="2"\; label="Yin"\; filenames="Y20052004573900171.png,Y20052004573900192.png"\; state="\{\{state\}\}">Yin</figure-callout>}}_2{\mathrm{Yout}}_1-{\mathrm{<figure-callout\; id="1"\; label="Yin"\; filenames="Y20052004573900171.png,Y20052004573900211.png"\; state="\{\{state\}\}">Yin</figure-callout>}}_1{\mathrm{<figure-callout\; id="2"\; label="Yout"\; filenames="Y20052004573900171.png,Y20052004573900192.png"\; state="\{\{state\}\}">Yout</figure-callout>}}_2}{{\mathrm{Yin}}_2-{\mathrm{<figure-callout\; id="1"\; label="Yin"\; filenames="Y20052004573900171.png,Y20052004573900211.png"\; state="\{\{state\}\}">Yin</figure-callout>}}_1};$

The input of described three class mapping blocks 604 (as shown in Figure 9) connects the output of comparator 601, comprise some multipliers, divider, adder and subtracter, its concrete connected mode is as follows: the value Yout of second flex point after the output of flex point computing circuit 4 stretches ₂Be input to a subtracter 604a with the output brightness maximum Max of statistical circuit 2, (i j) is input among the multiplier 604b the current figure image point of the output f of its output and brightness input circuit 1, the value Yout of second flex point after the output of flex point computing circuit 4 stretches ₂Initial value Yin with second flex point ₂Be input to a subtracter 604c, the output brightness maximum Max of the output of this subtracter and statistical circuit 2 is input among the multiplier 604d, and the output of this multiplier and the output of 604b are input among the adder 604e jointly; The initial value Yin of the output brightness maximum Max of statistical circuit 2 and second flex point of output of flex point computing circuit 4 ₂Be input to jointly among the subtracter 604f, the output of this subtracter and adder 604e is input among the divider 604g, obtains being output as the image f after contrast strengthens _Out(i, j), this module is carried out mapping transformation to luminance graph after receiving three classes mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{(\mathrm{Max}-{\mathrm{Yout}}_2)\&times;f(i,j)+\mathrm{Max}({\mathrm{Yout}}_2-{\mathrm{Yin}}_2)}{\mathrm{Max}-{\mathrm{<figure-callout\; id="2"\; label="Yin"\; filenames="Y20052004573900171.png,Y20052004573900192.png"\; state="\{\{state\}\}">Yin</figure-callout>}}_2};$

One brightness output module 7, its input connects the output of brightness mapping circuit 6, exports after the luminance transformation after being used for contrast strengthened is returned the original form of vision signal.

The brightness value that described brightness input circuit calculates can be the Y in the YUV model, or the V in the HSV model, or the I in the HIS model, perhaps the brightness of being derived by other rational brightness-formula.

The device of the dynamic raising video image effect of vision that the utility model provides, select piecewise linearity expansion commonly used for use, stretch selectively between certain section gray area, thereby improve picture quality, promptly no matter image is in bright field or details in a play not acted out on stage, but told through dialogues, all takes the piecewise function of three line segments, and the selection of two flex points on the piecewise function changes along with the conversion of brightness average, the variation of curve smoothing can be made, unexpected flicker can be in the scene that brightness gradually changes, do not occurred.

Claims (3)

1. a device that dynamically improves video image effect of vision is characterized in that, comprises:

One brightness input circuit (1), this circuit reads in entire image, and video image is calculated luminance graph, obtain representing monochrome information function f at the pixel of the capable j row of image i (i, j);

One statistics circuit (2), its input connects the output of brightness input circuit (1); This statistical circuit (2) comprises successively and to connect by circuit:

One image brightness mean value computation device, it is made up of brightness accumulator (201), number of pixels accumulator (208) and divider (202), calculates the brightness average M of entire image;

One maximum brightness detector (203) calculates brightness maximum Max;

One minimum brightness detector (204) calculates brightness minimum M in;

One adder (205) is used for statistic histogram, and this adder also connects a SRAM memory (206), is used to store the histogram array data;

One block statistics module, it comprises N * N image brightness mean value computation device that connects successively, maximum average detector (207m) and minimum mean detector (207n), each brightness mean value computation device is all by brightness accumulator (207a, 207b, 207c, 207d), number accumulator (207e, 207f, 207g, 207h) and divider (207i, 207j, 207k 207l) forms; This block statistics module is divided into N * N piece with image, calculates every brightness average respectively by N * N image brightness mean value computation device, and exports maximum average detector (207m) and minimum mean detector (207n) to, obtains maximum average M _MaxWith minimum mean M _Min

The even testing circuit of one brightness (3), the output of its input connection statistics circuit (2) judges in conjunction with histogram whether image belongs to the uneven situation of Luminance Distribution;

The even testing circuit of this brightness comprises three comparison modules and an AND circuit (308), and the output of described comparison module connects the input of AND circuit (308);

When the condition of three comparison modules satisfies simultaneously, when promptly following judgement formula (1) is set up,

The even testing circuit of brightness (3) output brightness irregularities flex point triggering signal; When the condition of any one comparator in three comparators is not being met, the even flex point triggering signal of the even testing circuit of brightness (3) output brightness;

In the following formula (1), H () is the pixel count of this image on certain gray scale, and Sum is the number of total picture element of entire image, C ₁, C ₂And C ₃All be constant, C ₁Represent maximum average M _MaxWith minimum mean M _MinThe amplitude that differs; C ₂Represent maximum average M _MaxWith minimum mean M _MinNear tonal range; C ₃For at maximum average M _MaxWith minimum mean M _MinNear point accounts for the ratio of full figure;

One contrast adjustment factor input circuit (5), output contrast adjustment coefficient k;

One flex point computing circuit (4), its input connects the output of even testing circuit of brightness (3) and statistical circuit (2), is used for calculating corner position; The input of this flex point computing circuit (4) also connects the output of contrast adjustment coefficient input circuit (5), receives the contrast adjustment coefficient k of its output;

This flex point computing circuit (4) comprises brightness irregularities flex point computing module (401) and the even flex point computing module of brightness (402);

When flex point computing circuit (4) received brightness irregularities flex point triggering signal, brightness irregularities flex point computing module (401) was worked, and the result is exported as the result of flex point computing circuit (4): choose 2 flex point A (Yin ₁, Yout ₁) and B (Yin ₂, Yout ₂), wherein

Yin ₁＝M _min+C ₄

Yin ₂＝M _max-C ₅ (2)

Yout ₁＝Yin ₁+C ₆

Yout ₂＝Yin ₂-C ₇

In the described formula (2), C ₄, C ₅, C ₆And C ₇All be constant, C ₄Expression flex point A and minimum mean M _MinBetween distance; C ₅Expression flex point B and maximum average M _MaxBetween distance; C ₆The stretch range of expression flex point A; C ₇The stretch range of expression flex point B;

When flex point computing circuit (4) receives the even flex point triggering signal of brightness, the even flex point computing module of brightness (402) work, and with the result output of result as flex point computing circuit (4): choose flex point A (Yin ₁, Yout ₁) and B (Yin ₂, Yout ₂), wherein, Yin ₁, Yin ₂For needs carry out 2 flex points that brightness stretches, they on the both sides of average, provide by following formula respectively:

Yin ₁＝M-a ₁ (3)

Yin ₂＝M+a ₂

In the formula (3), a ₁, a ₂Be the distance that needs stretching, be variable, choosing a ₁, a ₂Value the time, need guarantee the Yin that calculates ₁, Yin ₂Within the scope of [Min, Max];

Yout ₁, Yout ₂Be the flex point of the stretch zones of output image correspondence, it on the both sides of image brightness average M, provides by following formula respectively:

Yout ₁＝Yin ₁+k×(-C ₈×a ₁+(H/2+d-M))×(Yin ₂-Yin ₁) (4)

Yout ₂＝Yin ₂+k×(C ₈×a ₂+(H/2-M))×(Yin ₂-Yin ₁)

In the formula (4), k is the contrast adjustment coefficient; H is the brightness space maximum permissible value; D is the little positive number of presetting; C ₈It is the constant of presetting;

One brightness mapping circuit (6), its input connects the output of brightness input circuit (1), statistical circuit (2) and flex point computing circuit (4), and figure shines upon to original brightness, is dynamically improved contrast final brightness output f afterwards _Out(i, j);

Described brightness mapping circuit comprises comparator (601), a class mapping block (602), two class mapping blocks (603) and three class mapping blocks (604);

Described comparator (601) for brightness f (i j) screens, when Min≤f (i, j)＜Yin ₁The time, export class mapping triggering signal; Work as Yin ₁≤ f (i, j)＜Yin ₂The time, export two classes mapping triggering signal; Work as Yin ₂≤ f (i, j)≤during Max, export three classes mapping triggering signal;

The input of a described class mapping block (602) connects the output of comparator (601), and it carries out mapping transformation to luminance graph after receiving class mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{({\mathrm{Yout}}_1-\mathrm{Min})f(I,J)+\mathrm{Min}({\mathrm{Yin}}_1-{\mathrm{Yout}}_1)}{{\mathrm{Yin}}_1-\mathrm{Min}};$

The input of described two class mapping blocks (603) connects the output of comparator (601), and it carries out mapping transformation to luminance graph after receiving two classes mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{({\mathrm{Yout}}_2-{\mathrm{Yout}}_1)f(i,j)+{\mathrm{Yin}}_2{\mathrm{Yout}}_1-{\mathrm{Yin}}_1{\mathrm{Yout}}_2}{{\mathrm{Yin}}_2-{\mathrm{Yin}}_1};$

The input of described three class mapping blocks (604) connects the output of comparator (601), and it carries out mapping transformation to luminance graph after receiving three classes mapping triggering signal, obtain the image f after contrast strengthens _Out(i, j):

$f_{\mathrm{out}}(i,j)=\frac{(\mathrm{Max}-{\mathrm{Yout}}_2)\&times;f(i,j)+\mathrm{Max}({\mathrm{Yout}}_2-{\mathrm{Yin}}_2)}{\mathrm{Max}-{\mathrm{Yin}}_2};$

One brightness output module (7), its input connects the output of brightness mapping circuit (6), exports after the luminance transformation after being used for contrast strengthened is returned the original form of vision signal.

2. the device of dynamic raising video image effect of vision as claimed in claim 1, it is characterized in that, the brightness value that described brightness input circuit (1) calculates can be the Y in the YUV model, or the V in the HSV model, or the I in the HIS model, the perhaps brightness of deriving by other rational brightness-formula.

3. the device of dynamic raising video image effect of vision as claimed in claim 1 is characterized in that, the even testing circuit of described brightness (3) is provided with C ₁Value between 120～200; C is set ₂Value between 5～30; C is set ₃Value between 0.3～0.5.

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